1 //===-- DAGCombiner.cpp - Implement a DAG node combiner -------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This pass combines dag nodes to form fewer, simpler DAG nodes. It can be run
11 // both before and after the DAG is legalized.
13 // This pass is not a substitute for the LLVM IR instcombine pass. This pass is
14 // primarily intended to handle simplification opportunities that are implicit
15 // in the LLVM IR and exposed by the various codegen lowering phases.
17 //===----------------------------------------------------------------------===//
19 #define DEBUG_TYPE "dagcombine"
20 #include "llvm/CodeGen/SelectionDAG.h"
21 #include "llvm/DerivedTypes.h"
22 #include "llvm/LLVMContext.h"
23 #include "llvm/CodeGen/MachineFunction.h"
24 #include "llvm/CodeGen/MachineFrameInfo.h"
25 #include "llvm/CodeGen/PseudoSourceValue.h"
26 #include "llvm/Analysis/AliasAnalysis.h"
27 #include "llvm/Target/TargetData.h"
28 #include "llvm/Target/TargetLowering.h"
29 #include "llvm/Target/TargetMachine.h"
30 #include "llvm/Target/TargetOptions.h"
31 #include "llvm/ADT/SmallPtrSet.h"
32 #include "llvm/ADT/Statistic.h"
33 #include "llvm/Support/CommandLine.h"
34 #include "llvm/Support/Debug.h"
35 #include "llvm/Support/ErrorHandling.h"
36 #include "llvm/Support/MathExtras.h"
37 #include "llvm/Support/raw_ostream.h"
41 STATISTIC(NodesCombined , "Number of dag nodes combined");
42 STATISTIC(PreIndexedNodes , "Number of pre-indexed nodes created");
43 STATISTIC(PostIndexedNodes, "Number of post-indexed nodes created");
44 STATISTIC(OpsNarrowed , "Number of load/op/store narrowed");
48 CombinerAA("combiner-alias-analysis", cl::Hidden,
49 cl::desc("Turn on alias analysis during testing"));
52 CombinerGlobalAA("combiner-global-alias-analysis", cl::Hidden,
53 cl::desc("Include global information in alias analysis"));
55 //------------------------------ DAGCombiner ---------------------------------//
59 const TargetLowering &TLI;
61 CodeGenOpt::Level OptLevel;
65 // Worklist of all of the nodes that need to be simplified.
66 std::vector<SDNode*> WorkList;
68 // AA - Used for DAG load/store alias analysis.
71 /// AddUsersToWorkList - When an instruction is simplified, add all users of
72 /// the instruction to the work lists because they might get more simplified
75 void AddUsersToWorkList(SDNode *N) {
76 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end();
81 /// visit - call the node-specific routine that knows how to fold each
82 /// particular type of node.
83 SDValue visit(SDNode *N);
86 /// AddToWorkList - Add to the work list making sure it's instance is at the
87 /// the back (next to be processed.)
88 void AddToWorkList(SDNode *N) {
89 removeFromWorkList(N);
90 WorkList.push_back(N);
93 /// removeFromWorkList - remove all instances of N from the worklist.
95 void removeFromWorkList(SDNode *N) {
96 WorkList.erase(std::remove(WorkList.begin(), WorkList.end(), N),
100 SDValue CombineTo(SDNode *N, const SDValue *To, unsigned NumTo,
103 SDValue CombineTo(SDNode *N, SDValue Res, bool AddTo = true) {
104 return CombineTo(N, &Res, 1, AddTo);
107 SDValue CombineTo(SDNode *N, SDValue Res0, SDValue Res1,
109 SDValue To[] = { Res0, Res1 };
110 return CombineTo(N, To, 2, AddTo);
113 void CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO);
117 /// SimplifyDemandedBits - Check the specified integer node value to see if
118 /// it can be simplified or if things it uses can be simplified by bit
119 /// propagation. If so, return true.
120 bool SimplifyDemandedBits(SDValue Op) {
121 unsigned BitWidth = Op.getValueType().getScalarType().getSizeInBits();
122 APInt Demanded = APInt::getAllOnesValue(BitWidth);
123 return SimplifyDemandedBits(Op, Demanded);
126 bool SimplifyDemandedBits(SDValue Op, const APInt &Demanded);
128 bool CombineToPreIndexedLoadStore(SDNode *N);
129 bool CombineToPostIndexedLoadStore(SDNode *N);
131 void ReplaceLoadWithPromotedLoad(SDNode *Load, SDNode *ExtLoad);
132 SDValue PromoteOperand(SDValue Op, EVT PVT, bool &Replace);
133 SDValue SExtPromoteOperand(SDValue Op, EVT PVT);
134 SDValue ZExtPromoteOperand(SDValue Op, EVT PVT);
135 SDValue PromoteIntBinOp(SDValue Op);
136 SDValue PromoteIntShiftOp(SDValue Op);
137 SDValue PromoteExtend(SDValue Op);
138 bool PromoteLoad(SDValue Op);
140 /// combine - call the node-specific routine that knows how to fold each
141 /// particular type of node. If that doesn't do anything, try the
142 /// target-specific DAG combines.
143 SDValue combine(SDNode *N);
145 // Visitation implementation - Implement dag node combining for different
146 // node types. The semantics are as follows:
148 // SDValue.getNode() == 0 - No change was made
149 // SDValue.getNode() == N - N was replaced, is dead and has been handled.
150 // otherwise - N should be replaced by the returned Operand.
152 SDValue visitTokenFactor(SDNode *N);
153 SDValue visitMERGE_VALUES(SDNode *N);
154 SDValue visitADD(SDNode *N);
155 SDValue visitSUB(SDNode *N);
156 SDValue visitADDC(SDNode *N);
157 SDValue visitADDE(SDNode *N);
158 SDValue visitMUL(SDNode *N);
159 SDValue visitSDIV(SDNode *N);
160 SDValue visitUDIV(SDNode *N);
161 SDValue visitSREM(SDNode *N);
162 SDValue visitUREM(SDNode *N);
163 SDValue visitMULHU(SDNode *N);
164 SDValue visitMULHS(SDNode *N);
165 SDValue visitSMUL_LOHI(SDNode *N);
166 SDValue visitUMUL_LOHI(SDNode *N);
167 SDValue visitSDIVREM(SDNode *N);
168 SDValue visitUDIVREM(SDNode *N);
169 SDValue visitAND(SDNode *N);
170 SDValue visitOR(SDNode *N);
171 SDValue visitXOR(SDNode *N);
172 SDValue SimplifyVBinOp(SDNode *N);
173 SDValue visitSHL(SDNode *N);
174 SDValue visitSRA(SDNode *N);
175 SDValue visitSRL(SDNode *N);
176 SDValue visitCTLZ(SDNode *N);
177 SDValue visitCTTZ(SDNode *N);
178 SDValue visitCTPOP(SDNode *N);
179 SDValue visitSELECT(SDNode *N);
180 SDValue visitSELECT_CC(SDNode *N);
181 SDValue visitSETCC(SDNode *N);
182 SDValue visitSIGN_EXTEND(SDNode *N);
183 SDValue visitZERO_EXTEND(SDNode *N);
184 SDValue visitANY_EXTEND(SDNode *N);
185 SDValue visitSIGN_EXTEND_INREG(SDNode *N);
186 SDValue visitTRUNCATE(SDNode *N);
187 SDValue visitBITCAST(SDNode *N);
188 SDValue visitBUILD_PAIR(SDNode *N);
189 SDValue visitFADD(SDNode *N);
190 SDValue visitFSUB(SDNode *N);
191 SDValue visitFMUL(SDNode *N);
192 SDValue visitFDIV(SDNode *N);
193 SDValue visitFREM(SDNode *N);
194 SDValue visitFCOPYSIGN(SDNode *N);
195 SDValue visitSINT_TO_FP(SDNode *N);
196 SDValue visitUINT_TO_FP(SDNode *N);
197 SDValue visitFP_TO_SINT(SDNode *N);
198 SDValue visitFP_TO_UINT(SDNode *N);
199 SDValue visitFP_ROUND(SDNode *N);
200 SDValue visitFP_ROUND_INREG(SDNode *N);
201 SDValue visitFP_EXTEND(SDNode *N);
202 SDValue visitFNEG(SDNode *N);
203 SDValue visitFABS(SDNode *N);
204 SDValue visitBRCOND(SDNode *N);
205 SDValue visitBR_CC(SDNode *N);
206 SDValue visitLOAD(SDNode *N);
207 SDValue visitSTORE(SDNode *N);
208 SDValue visitINSERT_VECTOR_ELT(SDNode *N);
209 SDValue visitEXTRACT_VECTOR_ELT(SDNode *N);
210 SDValue visitBUILD_VECTOR(SDNode *N);
211 SDValue visitCONCAT_VECTORS(SDNode *N);
212 SDValue visitVECTOR_SHUFFLE(SDNode *N);
213 SDValue visitMEMBARRIER(SDNode *N);
215 SDValue XformToShuffleWithZero(SDNode *N);
216 SDValue ReassociateOps(unsigned Opc, DebugLoc DL, SDValue LHS, SDValue RHS);
218 SDValue visitShiftByConstant(SDNode *N, unsigned Amt);
220 bool SimplifySelectOps(SDNode *SELECT, SDValue LHS, SDValue RHS);
221 SDValue SimplifyBinOpWithSameOpcodeHands(SDNode *N);
222 SDValue SimplifySelect(DebugLoc DL, SDValue N0, SDValue N1, SDValue N2);
223 SDValue SimplifySelectCC(DebugLoc DL, SDValue N0, SDValue N1, SDValue N2,
224 SDValue N3, ISD::CondCode CC,
225 bool NotExtCompare = false);
226 SDValue SimplifySetCC(EVT VT, SDValue N0, SDValue N1, ISD::CondCode Cond,
227 DebugLoc DL, bool foldBooleans = true);
228 SDValue SimplifyNodeWithTwoResults(SDNode *N, unsigned LoOp,
230 SDValue CombineConsecutiveLoads(SDNode *N, EVT VT);
231 SDValue ConstantFoldBITCASTofBUILD_VECTOR(SDNode *, EVT);
232 SDValue BuildSDIV(SDNode *N);
233 SDValue BuildUDIV(SDNode *N);
234 SDNode *MatchRotate(SDValue LHS, SDValue RHS, DebugLoc DL);
235 SDValue ReduceLoadWidth(SDNode *N);
236 SDValue ReduceLoadOpStoreWidth(SDNode *N);
238 SDValue GetDemandedBits(SDValue V, const APInt &Mask);
240 /// GatherAllAliases - Walk up chain skipping non-aliasing memory nodes,
241 /// looking for aliasing nodes and adding them to the Aliases vector.
242 void GatherAllAliases(SDNode *N, SDValue OriginalChain,
243 SmallVector<SDValue, 8> &Aliases);
245 /// isAlias - Return true if there is any possibility that the two addresses
247 bool isAlias(SDValue Ptr1, int64_t Size1,
248 const Value *SrcValue1, int SrcValueOffset1,
249 unsigned SrcValueAlign1,
250 const MDNode *TBAAInfo1,
251 SDValue Ptr2, int64_t Size2,
252 const Value *SrcValue2, int SrcValueOffset2,
253 unsigned SrcValueAlign2,
254 const MDNode *TBAAInfo2) const;
256 /// FindAliasInfo - Extracts the relevant alias information from the memory
257 /// node. Returns true if the operand was a load.
258 bool FindAliasInfo(SDNode *N,
259 SDValue &Ptr, int64_t &Size,
260 const Value *&SrcValue, int &SrcValueOffset,
261 unsigned &SrcValueAlignment,
262 const MDNode *&TBAAInfo) const;
264 /// FindBetterChain - Walk up chain skipping non-aliasing memory nodes,
265 /// looking for a better chain (aliasing node.)
266 SDValue FindBetterChain(SDNode *N, SDValue Chain);
269 DAGCombiner(SelectionDAG &D, AliasAnalysis &A, CodeGenOpt::Level OL)
270 : DAG(D), TLI(D.getTargetLoweringInfo()), Level(Unrestricted),
271 OptLevel(OL), LegalOperations(false), LegalTypes(false), AA(A) {}
273 /// Run - runs the dag combiner on all nodes in the work list
274 void Run(CombineLevel AtLevel);
276 SelectionDAG &getDAG() const { return DAG; }
278 /// getShiftAmountTy - Returns a type large enough to hold any valid
279 /// shift amount - before type legalization these can be huge.
280 EVT getShiftAmountTy() {
281 return LegalTypes ? TLI.getShiftAmountTy() : TLI.getPointerTy();
284 /// isTypeLegal - This method returns true if we are running before type
285 /// legalization or if the specified VT is legal.
286 bool isTypeLegal(const EVT &VT) {
287 if (!LegalTypes) return true;
288 return TLI.isTypeLegal(VT);
295 /// WorkListRemover - This class is a DAGUpdateListener that removes any deleted
296 /// nodes from the worklist.
297 class WorkListRemover : public SelectionDAG::DAGUpdateListener {
300 explicit WorkListRemover(DAGCombiner &dc) : DC(dc) {}
302 virtual void NodeDeleted(SDNode *N, SDNode *E) {
303 DC.removeFromWorkList(N);
306 virtual void NodeUpdated(SDNode *N) {
312 //===----------------------------------------------------------------------===//
313 // TargetLowering::DAGCombinerInfo implementation
314 //===----------------------------------------------------------------------===//
316 void TargetLowering::DAGCombinerInfo::AddToWorklist(SDNode *N) {
317 ((DAGCombiner*)DC)->AddToWorkList(N);
320 SDValue TargetLowering::DAGCombinerInfo::
321 CombineTo(SDNode *N, const std::vector<SDValue> &To, bool AddTo) {
322 return ((DAGCombiner*)DC)->CombineTo(N, &To[0], To.size(), AddTo);
325 SDValue TargetLowering::DAGCombinerInfo::
326 CombineTo(SDNode *N, SDValue Res, bool AddTo) {
327 return ((DAGCombiner*)DC)->CombineTo(N, Res, AddTo);
331 SDValue TargetLowering::DAGCombinerInfo::
332 CombineTo(SDNode *N, SDValue Res0, SDValue Res1, bool AddTo) {
333 return ((DAGCombiner*)DC)->CombineTo(N, Res0, Res1, AddTo);
336 void TargetLowering::DAGCombinerInfo::
337 CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO) {
338 return ((DAGCombiner*)DC)->CommitTargetLoweringOpt(TLO);
341 //===----------------------------------------------------------------------===//
343 //===----------------------------------------------------------------------===//
345 /// isNegatibleForFree - Return 1 if we can compute the negated form of the
346 /// specified expression for the same cost as the expression itself, or 2 if we
347 /// can compute the negated form more cheaply than the expression itself.
348 static char isNegatibleForFree(SDValue Op, bool LegalOperations,
349 unsigned Depth = 0) {
350 // No compile time optimizations on this type.
351 if (Op.getValueType() == MVT::ppcf128)
354 // fneg is removable even if it has multiple uses.
355 if (Op.getOpcode() == ISD::FNEG) return 2;
357 // Don't allow anything with multiple uses.
358 if (!Op.hasOneUse()) return 0;
360 // Don't recurse exponentially.
361 if (Depth > 6) return 0;
363 switch (Op.getOpcode()) {
364 default: return false;
365 case ISD::ConstantFP:
366 // Don't invert constant FP values after legalize. The negated constant
367 // isn't necessarily legal.
368 return LegalOperations ? 0 : 1;
370 // FIXME: determine better conditions for this xform.
371 if (!UnsafeFPMath) return 0;
373 // fold (fsub (fadd A, B)) -> (fsub (fneg A), B)
374 if (char V = isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1))
376 // fold (fneg (fadd A, B)) -> (fsub (fneg B), A)
377 return isNegatibleForFree(Op.getOperand(1), LegalOperations, Depth+1);
379 // We can't turn -(A-B) into B-A when we honor signed zeros.
380 if (!UnsafeFPMath) return 0;
382 // fold (fneg (fsub A, B)) -> (fsub B, A)
387 if (HonorSignDependentRoundingFPMath()) return 0;
389 // fold (fneg (fmul X, Y)) -> (fmul (fneg X), Y) or (fmul X, (fneg Y))
390 if (char V = isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1))
393 return isNegatibleForFree(Op.getOperand(1), LegalOperations, Depth+1);
398 return isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1);
402 /// GetNegatedExpression - If isNegatibleForFree returns true, this function
403 /// returns the newly negated expression.
404 static SDValue GetNegatedExpression(SDValue Op, SelectionDAG &DAG,
405 bool LegalOperations, unsigned Depth = 0) {
406 // fneg is removable even if it has multiple uses.
407 if (Op.getOpcode() == ISD::FNEG) return Op.getOperand(0);
409 // Don't allow anything with multiple uses.
410 assert(Op.hasOneUse() && "Unknown reuse!");
412 assert(Depth <= 6 && "GetNegatedExpression doesn't match isNegatibleForFree");
413 switch (Op.getOpcode()) {
414 default: llvm_unreachable("Unknown code");
415 case ISD::ConstantFP: {
416 APFloat V = cast<ConstantFPSDNode>(Op)->getValueAPF();
418 return DAG.getConstantFP(V, Op.getValueType());
421 // FIXME: determine better conditions for this xform.
422 assert(UnsafeFPMath);
424 // fold (fneg (fadd A, B)) -> (fsub (fneg A), B)
425 if (isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1))
426 return DAG.getNode(ISD::FSUB, Op.getDebugLoc(), Op.getValueType(),
427 GetNegatedExpression(Op.getOperand(0), DAG,
428 LegalOperations, Depth+1),
430 // fold (fneg (fadd A, B)) -> (fsub (fneg B), A)
431 return DAG.getNode(ISD::FSUB, Op.getDebugLoc(), Op.getValueType(),
432 GetNegatedExpression(Op.getOperand(1), DAG,
433 LegalOperations, Depth+1),
436 // We can't turn -(A-B) into B-A when we honor signed zeros.
437 assert(UnsafeFPMath);
439 // fold (fneg (fsub 0, B)) -> B
440 if (ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(Op.getOperand(0)))
441 if (N0CFP->getValueAPF().isZero())
442 return Op.getOperand(1);
444 // fold (fneg (fsub A, B)) -> (fsub B, A)
445 return DAG.getNode(ISD::FSUB, Op.getDebugLoc(), Op.getValueType(),
446 Op.getOperand(1), Op.getOperand(0));
450 assert(!HonorSignDependentRoundingFPMath());
452 // fold (fneg (fmul X, Y)) -> (fmul (fneg X), Y)
453 if (isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1))
454 return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), Op.getValueType(),
455 GetNegatedExpression(Op.getOperand(0), DAG,
456 LegalOperations, Depth+1),
459 // fold (fneg (fmul X, Y)) -> (fmul X, (fneg Y))
460 return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), Op.getValueType(),
462 GetNegatedExpression(Op.getOperand(1), DAG,
463 LegalOperations, Depth+1));
467 return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), Op.getValueType(),
468 GetNegatedExpression(Op.getOperand(0), DAG,
469 LegalOperations, Depth+1));
471 return DAG.getNode(ISD::FP_ROUND, Op.getDebugLoc(), Op.getValueType(),
472 GetNegatedExpression(Op.getOperand(0), DAG,
473 LegalOperations, Depth+1),
479 // isSetCCEquivalent - Return true if this node is a setcc, or is a select_cc
480 // that selects between the values 1 and 0, making it equivalent to a setcc.
481 // Also, set the incoming LHS, RHS, and CC references to the appropriate
482 // nodes based on the type of node we are checking. This simplifies life a
483 // bit for the callers.
484 static bool isSetCCEquivalent(SDValue N, SDValue &LHS, SDValue &RHS,
486 if (N.getOpcode() == ISD::SETCC) {
487 LHS = N.getOperand(0);
488 RHS = N.getOperand(1);
489 CC = N.getOperand(2);
492 if (N.getOpcode() == ISD::SELECT_CC &&
493 N.getOperand(2).getOpcode() == ISD::Constant &&
494 N.getOperand(3).getOpcode() == ISD::Constant &&
495 cast<ConstantSDNode>(N.getOperand(2))->getAPIntValue() == 1 &&
496 cast<ConstantSDNode>(N.getOperand(3))->isNullValue()) {
497 LHS = N.getOperand(0);
498 RHS = N.getOperand(1);
499 CC = N.getOperand(4);
505 // isOneUseSetCC - Return true if this is a SetCC-equivalent operation with only
506 // one use. If this is true, it allows the users to invert the operation for
507 // free when it is profitable to do so.
508 static bool isOneUseSetCC(SDValue N) {
510 if (isSetCCEquivalent(N, N0, N1, N2) && N.getNode()->hasOneUse())
515 SDValue DAGCombiner::ReassociateOps(unsigned Opc, DebugLoc DL,
516 SDValue N0, SDValue N1) {
517 EVT VT = N0.getValueType();
518 if (N0.getOpcode() == Opc && isa<ConstantSDNode>(N0.getOperand(1))) {
519 if (isa<ConstantSDNode>(N1)) {
520 // reassoc. (op (op x, c1), c2) -> (op x, (op c1, c2))
522 DAG.FoldConstantArithmetic(Opc, VT,
523 cast<ConstantSDNode>(N0.getOperand(1)),
524 cast<ConstantSDNode>(N1));
525 return DAG.getNode(Opc, DL, VT, N0.getOperand(0), OpNode);
526 } else if (N0.hasOneUse()) {
527 // reassoc. (op (op x, c1), y) -> (op (op x, y), c1) iff x+c1 has one use
528 SDValue OpNode = DAG.getNode(Opc, N0.getDebugLoc(), VT,
529 N0.getOperand(0), N1);
530 AddToWorkList(OpNode.getNode());
531 return DAG.getNode(Opc, DL, VT, OpNode, N0.getOperand(1));
535 if (N1.getOpcode() == Opc && isa<ConstantSDNode>(N1.getOperand(1))) {
536 if (isa<ConstantSDNode>(N0)) {
537 // reassoc. (op c2, (op x, c1)) -> (op x, (op c1, c2))
539 DAG.FoldConstantArithmetic(Opc, VT,
540 cast<ConstantSDNode>(N1.getOperand(1)),
541 cast<ConstantSDNode>(N0));
542 return DAG.getNode(Opc, DL, VT, N1.getOperand(0), OpNode);
543 } else if (N1.hasOneUse()) {
544 // reassoc. (op y, (op x, c1)) -> (op (op x, y), c1) iff x+c1 has one use
545 SDValue OpNode = DAG.getNode(Opc, N0.getDebugLoc(), VT,
546 N1.getOperand(0), N0);
547 AddToWorkList(OpNode.getNode());
548 return DAG.getNode(Opc, DL, VT, OpNode, N1.getOperand(1));
555 SDValue DAGCombiner::CombineTo(SDNode *N, const SDValue *To, unsigned NumTo,
557 assert(N->getNumValues() == NumTo && "Broken CombineTo call!");
559 DEBUG(dbgs() << "\nReplacing.1 ";
561 dbgs() << "\nWith: ";
562 To[0].getNode()->dump(&DAG);
563 dbgs() << " and " << NumTo-1 << " other values\n";
564 for (unsigned i = 0, e = NumTo; i != e; ++i)
565 assert((!To[i].getNode() ||
566 N->getValueType(i) == To[i].getValueType()) &&
567 "Cannot combine value to value of different type!"));
568 WorkListRemover DeadNodes(*this);
569 DAG.ReplaceAllUsesWith(N, To, &DeadNodes);
572 // Push the new nodes and any users onto the worklist
573 for (unsigned i = 0, e = NumTo; i != e; ++i) {
574 if (To[i].getNode()) {
575 AddToWorkList(To[i].getNode());
576 AddUsersToWorkList(To[i].getNode());
581 // Finally, if the node is now dead, remove it from the graph. The node
582 // may not be dead if the replacement process recursively simplified to
583 // something else needing this node.
584 if (N->use_empty()) {
585 // Nodes can be reintroduced into the worklist. Make sure we do not
586 // process a node that has been replaced.
587 removeFromWorkList(N);
589 // Finally, since the node is now dead, remove it from the graph.
592 return SDValue(N, 0);
596 CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO) {
597 // Replace all uses. If any nodes become isomorphic to other nodes and
598 // are deleted, make sure to remove them from our worklist.
599 WorkListRemover DeadNodes(*this);
600 DAG.ReplaceAllUsesOfValueWith(TLO.Old, TLO.New, &DeadNodes);
602 // Push the new node and any (possibly new) users onto the worklist.
603 AddToWorkList(TLO.New.getNode());
604 AddUsersToWorkList(TLO.New.getNode());
606 // Finally, if the node is now dead, remove it from the graph. The node
607 // may not be dead if the replacement process recursively simplified to
608 // something else needing this node.
609 if (TLO.Old.getNode()->use_empty()) {
610 removeFromWorkList(TLO.Old.getNode());
612 // If the operands of this node are only used by the node, they will now
613 // be dead. Make sure to visit them first to delete dead nodes early.
614 for (unsigned i = 0, e = TLO.Old.getNode()->getNumOperands(); i != e; ++i)
615 if (TLO.Old.getNode()->getOperand(i).getNode()->hasOneUse())
616 AddToWorkList(TLO.Old.getNode()->getOperand(i).getNode());
618 DAG.DeleteNode(TLO.Old.getNode());
622 /// SimplifyDemandedBits - Check the specified integer node value to see if
623 /// it can be simplified or if things it uses can be simplified by bit
624 /// propagation. If so, return true.
625 bool DAGCombiner::SimplifyDemandedBits(SDValue Op, const APInt &Demanded) {
626 TargetLowering::TargetLoweringOpt TLO(DAG, LegalTypes, LegalOperations);
627 APInt KnownZero, KnownOne;
628 if (!TLI.SimplifyDemandedBits(Op, Demanded, KnownZero, KnownOne, TLO))
632 AddToWorkList(Op.getNode());
634 // Replace the old value with the new one.
636 DEBUG(dbgs() << "\nReplacing.2 ";
637 TLO.Old.getNode()->dump(&DAG);
638 dbgs() << "\nWith: ";
639 TLO.New.getNode()->dump(&DAG);
642 CommitTargetLoweringOpt(TLO);
646 void DAGCombiner::ReplaceLoadWithPromotedLoad(SDNode *Load, SDNode *ExtLoad) {
647 DebugLoc dl = Load->getDebugLoc();
648 EVT VT = Load->getValueType(0);
649 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, dl, VT, SDValue(ExtLoad, 0));
651 DEBUG(dbgs() << "\nReplacing.9 ";
653 dbgs() << "\nWith: ";
654 Trunc.getNode()->dump(&DAG);
656 WorkListRemover DeadNodes(*this);
657 DAG.ReplaceAllUsesOfValueWith(SDValue(Load, 0), Trunc, &DeadNodes);
658 DAG.ReplaceAllUsesOfValueWith(SDValue(Load, 1), SDValue(ExtLoad, 1),
660 removeFromWorkList(Load);
661 DAG.DeleteNode(Load);
662 AddToWorkList(Trunc.getNode());
665 SDValue DAGCombiner::PromoteOperand(SDValue Op, EVT PVT, bool &Replace) {
667 DebugLoc dl = Op.getDebugLoc();
668 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(Op)) {
669 EVT MemVT = LD->getMemoryVT();
670 ISD::LoadExtType ExtType = ISD::isNON_EXTLoad(LD)
671 ? (TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT) ? ISD::ZEXTLOAD
673 : LD->getExtensionType();
675 return DAG.getExtLoad(ExtType, PVT, dl,
676 LD->getChain(), LD->getBasePtr(),
677 LD->getPointerInfo(),
678 MemVT, LD->isVolatile(),
679 LD->isNonTemporal(), LD->getAlignment());
682 unsigned Opc = Op.getOpcode();
685 case ISD::AssertSext:
686 return DAG.getNode(ISD::AssertSext, dl, PVT,
687 SExtPromoteOperand(Op.getOperand(0), PVT),
689 case ISD::AssertZext:
690 return DAG.getNode(ISD::AssertZext, dl, PVT,
691 ZExtPromoteOperand(Op.getOperand(0), PVT),
693 case ISD::Constant: {
695 Op.getValueType().isByteSized() ? ISD::SIGN_EXTEND : ISD::ZERO_EXTEND;
696 return DAG.getNode(ExtOpc, dl, PVT, Op);
700 if (!TLI.isOperationLegal(ISD::ANY_EXTEND, PVT))
702 return DAG.getNode(ISD::ANY_EXTEND, dl, PVT, Op);
705 SDValue DAGCombiner::SExtPromoteOperand(SDValue Op, EVT PVT) {
706 if (!TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, PVT))
708 EVT OldVT = Op.getValueType();
709 DebugLoc dl = Op.getDebugLoc();
710 bool Replace = false;
711 SDValue NewOp = PromoteOperand(Op, PVT, Replace);
712 if (NewOp.getNode() == 0)
714 AddToWorkList(NewOp.getNode());
717 ReplaceLoadWithPromotedLoad(Op.getNode(), NewOp.getNode());
718 return DAG.getNode(ISD::SIGN_EXTEND_INREG, dl, NewOp.getValueType(), NewOp,
719 DAG.getValueType(OldVT));
722 SDValue DAGCombiner::ZExtPromoteOperand(SDValue Op, EVT PVT) {
723 EVT OldVT = Op.getValueType();
724 DebugLoc dl = Op.getDebugLoc();
725 bool Replace = false;
726 SDValue NewOp = PromoteOperand(Op, PVT, Replace);
727 if (NewOp.getNode() == 0)
729 AddToWorkList(NewOp.getNode());
732 ReplaceLoadWithPromotedLoad(Op.getNode(), NewOp.getNode());
733 return DAG.getZeroExtendInReg(NewOp, dl, OldVT);
736 /// PromoteIntBinOp - Promote the specified integer binary operation if the
737 /// target indicates it is beneficial. e.g. On x86, it's usually better to
738 /// promote i16 operations to i32 since i16 instructions are longer.
739 SDValue DAGCombiner::PromoteIntBinOp(SDValue Op) {
740 if (!LegalOperations)
743 EVT VT = Op.getValueType();
744 if (VT.isVector() || !VT.isInteger())
747 // If operation type is 'undesirable', e.g. i16 on x86, consider
749 unsigned Opc = Op.getOpcode();
750 if (TLI.isTypeDesirableForOp(Opc, VT))
754 // Consult target whether it is a good idea to promote this operation and
755 // what's the right type to promote it to.
756 if (TLI.IsDesirableToPromoteOp(Op, PVT)) {
757 assert(PVT != VT && "Don't know what type to promote to!");
759 bool Replace0 = false;
760 SDValue N0 = Op.getOperand(0);
761 SDValue NN0 = PromoteOperand(N0, PVT, Replace0);
762 if (NN0.getNode() == 0)
765 bool Replace1 = false;
766 SDValue N1 = Op.getOperand(1);
771 NN1 = PromoteOperand(N1, PVT, Replace1);
772 if (NN1.getNode() == 0)
776 AddToWorkList(NN0.getNode());
778 AddToWorkList(NN1.getNode());
781 ReplaceLoadWithPromotedLoad(N0.getNode(), NN0.getNode());
783 ReplaceLoadWithPromotedLoad(N1.getNode(), NN1.getNode());
785 DEBUG(dbgs() << "\nPromoting ";
786 Op.getNode()->dump(&DAG));
787 DebugLoc dl = Op.getDebugLoc();
788 return DAG.getNode(ISD::TRUNCATE, dl, VT,
789 DAG.getNode(Opc, dl, PVT, NN0, NN1));
794 /// PromoteIntShiftOp - Promote the specified integer shift operation if the
795 /// target indicates it is beneficial. e.g. On x86, it's usually better to
796 /// promote i16 operations to i32 since i16 instructions are longer.
797 SDValue DAGCombiner::PromoteIntShiftOp(SDValue Op) {
798 if (!LegalOperations)
801 EVT VT = Op.getValueType();
802 if (VT.isVector() || !VT.isInteger())
805 // If operation type is 'undesirable', e.g. i16 on x86, consider
807 unsigned Opc = Op.getOpcode();
808 if (TLI.isTypeDesirableForOp(Opc, VT))
812 // Consult target whether it is a good idea to promote this operation and
813 // what's the right type to promote it to.
814 if (TLI.IsDesirableToPromoteOp(Op, PVT)) {
815 assert(PVT != VT && "Don't know what type to promote to!");
817 bool Replace = false;
818 SDValue N0 = Op.getOperand(0);
820 N0 = SExtPromoteOperand(Op.getOperand(0), PVT);
821 else if (Opc == ISD::SRL)
822 N0 = ZExtPromoteOperand(Op.getOperand(0), PVT);
824 N0 = PromoteOperand(N0, PVT, Replace);
825 if (N0.getNode() == 0)
828 AddToWorkList(N0.getNode());
830 ReplaceLoadWithPromotedLoad(Op.getOperand(0).getNode(), N0.getNode());
832 DEBUG(dbgs() << "\nPromoting ";
833 Op.getNode()->dump(&DAG));
834 DebugLoc dl = Op.getDebugLoc();
835 return DAG.getNode(ISD::TRUNCATE, dl, VT,
836 DAG.getNode(Opc, dl, PVT, N0, Op.getOperand(1)));
841 SDValue DAGCombiner::PromoteExtend(SDValue Op) {
842 if (!LegalOperations)
845 EVT VT = Op.getValueType();
846 if (VT.isVector() || !VT.isInteger())
849 // If operation type is 'undesirable', e.g. i16 on x86, consider
851 unsigned Opc = Op.getOpcode();
852 if (TLI.isTypeDesirableForOp(Opc, VT))
856 // Consult target whether it is a good idea to promote this operation and
857 // what's the right type to promote it to.
858 if (TLI.IsDesirableToPromoteOp(Op, PVT)) {
859 assert(PVT != VT && "Don't know what type to promote to!");
860 // fold (aext (aext x)) -> (aext x)
861 // fold (aext (zext x)) -> (zext x)
862 // fold (aext (sext x)) -> (sext x)
863 DEBUG(dbgs() << "\nPromoting ";
864 Op.getNode()->dump(&DAG));
865 return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), VT, Op.getOperand(0));
870 bool DAGCombiner::PromoteLoad(SDValue Op) {
871 if (!LegalOperations)
874 EVT VT = Op.getValueType();
875 if (VT.isVector() || !VT.isInteger())
878 // If operation type is 'undesirable', e.g. i16 on x86, consider
880 unsigned Opc = Op.getOpcode();
881 if (TLI.isTypeDesirableForOp(Opc, VT))
885 // Consult target whether it is a good idea to promote this operation and
886 // what's the right type to promote it to.
887 if (TLI.IsDesirableToPromoteOp(Op, PVT)) {
888 assert(PVT != VT && "Don't know what type to promote to!");
890 DebugLoc dl = Op.getDebugLoc();
891 SDNode *N = Op.getNode();
892 LoadSDNode *LD = cast<LoadSDNode>(N);
893 EVT MemVT = LD->getMemoryVT();
894 ISD::LoadExtType ExtType = ISD::isNON_EXTLoad(LD)
895 ? (TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT) ? ISD::ZEXTLOAD
897 : LD->getExtensionType();
898 SDValue NewLD = DAG.getExtLoad(ExtType, PVT, dl,
899 LD->getChain(), LD->getBasePtr(),
900 LD->getPointerInfo(),
901 MemVT, LD->isVolatile(),
902 LD->isNonTemporal(), LD->getAlignment());
903 SDValue Result = DAG.getNode(ISD::TRUNCATE, dl, VT, NewLD);
905 DEBUG(dbgs() << "\nPromoting ";
908 Result.getNode()->dump(&DAG);
910 WorkListRemover DeadNodes(*this);
911 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result, &DeadNodes);
912 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), NewLD.getValue(1), &DeadNodes);
913 removeFromWorkList(N);
915 AddToWorkList(Result.getNode());
922 //===----------------------------------------------------------------------===//
923 // Main DAG Combiner implementation
924 //===----------------------------------------------------------------------===//
926 void DAGCombiner::Run(CombineLevel AtLevel) {
927 // set the instance variables, so that the various visit routines may use it.
929 LegalOperations = Level >= NoIllegalOperations;
930 LegalTypes = Level >= NoIllegalTypes;
932 // Add all the dag nodes to the worklist.
933 WorkList.reserve(DAG.allnodes_size());
934 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(),
935 E = DAG.allnodes_end(); I != E; ++I)
936 WorkList.push_back(I);
938 // Create a dummy node (which is not added to allnodes), that adds a reference
939 // to the root node, preventing it from being deleted, and tracking any
940 // changes of the root.
941 HandleSDNode Dummy(DAG.getRoot());
943 // The root of the dag may dangle to deleted nodes until the dag combiner is
944 // done. Set it to null to avoid confusion.
945 DAG.setRoot(SDValue());
947 // while the worklist isn't empty, inspect the node on the end of it and
948 // try and combine it.
949 while (!WorkList.empty()) {
950 SDNode *N = WorkList.back();
953 // If N has no uses, it is dead. Make sure to revisit all N's operands once
954 // N is deleted from the DAG, since they too may now be dead or may have a
955 // reduced number of uses, allowing other xforms.
956 if (N->use_empty() && N != &Dummy) {
957 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
958 AddToWorkList(N->getOperand(i).getNode());
964 SDValue RV = combine(N);
966 if (RV.getNode() == 0)
971 // If we get back the same node we passed in, rather than a new node or
972 // zero, we know that the node must have defined multiple values and
973 // CombineTo was used. Since CombineTo takes care of the worklist
974 // mechanics for us, we have no work to do in this case.
975 if (RV.getNode() == N)
978 assert(N->getOpcode() != ISD::DELETED_NODE &&
979 RV.getNode()->getOpcode() != ISD::DELETED_NODE &&
980 "Node was deleted but visit returned new node!");
982 DEBUG(dbgs() << "\nReplacing.3 ";
984 dbgs() << "\nWith: ";
985 RV.getNode()->dump(&DAG);
987 WorkListRemover DeadNodes(*this);
988 if (N->getNumValues() == RV.getNode()->getNumValues())
989 DAG.ReplaceAllUsesWith(N, RV.getNode(), &DeadNodes);
991 assert(N->getValueType(0) == RV.getValueType() &&
992 N->getNumValues() == 1 && "Type mismatch");
994 DAG.ReplaceAllUsesWith(N, &OpV, &DeadNodes);
997 // Push the new node and any users onto the worklist
998 AddToWorkList(RV.getNode());
999 AddUsersToWorkList(RV.getNode());
1001 // Add any uses of the old node to the worklist in case this node is the
1002 // last one that uses them. They may become dead after this node is
1004 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
1005 AddToWorkList(N->getOperand(i).getNode());
1007 // Finally, if the node is now dead, remove it from the graph. The node
1008 // may not be dead if the replacement process recursively simplified to
1009 // something else needing this node.
1010 if (N->use_empty()) {
1011 // Nodes can be reintroduced into the worklist. Make sure we do not
1012 // process a node that has been replaced.
1013 removeFromWorkList(N);
1015 // Finally, since the node is now dead, remove it from the graph.
1020 // If the root changed (e.g. it was a dead load, update the root).
1021 DAG.setRoot(Dummy.getValue());
1024 SDValue DAGCombiner::visit(SDNode *N) {
1025 switch (N->getOpcode()) {
1027 case ISD::TokenFactor: return visitTokenFactor(N);
1028 case ISD::MERGE_VALUES: return visitMERGE_VALUES(N);
1029 case ISD::ADD: return visitADD(N);
1030 case ISD::SUB: return visitSUB(N);
1031 case ISD::ADDC: return visitADDC(N);
1032 case ISD::ADDE: return visitADDE(N);
1033 case ISD::MUL: return visitMUL(N);
1034 case ISD::SDIV: return visitSDIV(N);
1035 case ISD::UDIV: return visitUDIV(N);
1036 case ISD::SREM: return visitSREM(N);
1037 case ISD::UREM: return visitUREM(N);
1038 case ISD::MULHU: return visitMULHU(N);
1039 case ISD::MULHS: return visitMULHS(N);
1040 case ISD::SMUL_LOHI: return visitSMUL_LOHI(N);
1041 case ISD::UMUL_LOHI: return visitUMUL_LOHI(N);
1042 case ISD::SDIVREM: return visitSDIVREM(N);
1043 case ISD::UDIVREM: return visitUDIVREM(N);
1044 case ISD::AND: return visitAND(N);
1045 case ISD::OR: return visitOR(N);
1046 case ISD::XOR: return visitXOR(N);
1047 case ISD::SHL: return visitSHL(N);
1048 case ISD::SRA: return visitSRA(N);
1049 case ISD::SRL: return visitSRL(N);
1050 case ISD::CTLZ: return visitCTLZ(N);
1051 case ISD::CTTZ: return visitCTTZ(N);
1052 case ISD::CTPOP: return visitCTPOP(N);
1053 case ISD::SELECT: return visitSELECT(N);
1054 case ISD::SELECT_CC: return visitSELECT_CC(N);
1055 case ISD::SETCC: return visitSETCC(N);
1056 case ISD::SIGN_EXTEND: return visitSIGN_EXTEND(N);
1057 case ISD::ZERO_EXTEND: return visitZERO_EXTEND(N);
1058 case ISD::ANY_EXTEND: return visitANY_EXTEND(N);
1059 case ISD::SIGN_EXTEND_INREG: return visitSIGN_EXTEND_INREG(N);
1060 case ISD::TRUNCATE: return visitTRUNCATE(N);
1061 case ISD::BITCAST: return visitBITCAST(N);
1062 case ISD::BUILD_PAIR: return visitBUILD_PAIR(N);
1063 case ISD::FADD: return visitFADD(N);
1064 case ISD::FSUB: return visitFSUB(N);
1065 case ISD::FMUL: return visitFMUL(N);
1066 case ISD::FDIV: return visitFDIV(N);
1067 case ISD::FREM: return visitFREM(N);
1068 case ISD::FCOPYSIGN: return visitFCOPYSIGN(N);
1069 case ISD::SINT_TO_FP: return visitSINT_TO_FP(N);
1070 case ISD::UINT_TO_FP: return visitUINT_TO_FP(N);
1071 case ISD::FP_TO_SINT: return visitFP_TO_SINT(N);
1072 case ISD::FP_TO_UINT: return visitFP_TO_UINT(N);
1073 case ISD::FP_ROUND: return visitFP_ROUND(N);
1074 case ISD::FP_ROUND_INREG: return visitFP_ROUND_INREG(N);
1075 case ISD::FP_EXTEND: return visitFP_EXTEND(N);
1076 case ISD::FNEG: return visitFNEG(N);
1077 case ISD::FABS: return visitFABS(N);
1078 case ISD::BRCOND: return visitBRCOND(N);
1079 case ISD::BR_CC: return visitBR_CC(N);
1080 case ISD::LOAD: return visitLOAD(N);
1081 case ISD::STORE: return visitSTORE(N);
1082 case ISD::INSERT_VECTOR_ELT: return visitINSERT_VECTOR_ELT(N);
1083 case ISD::EXTRACT_VECTOR_ELT: return visitEXTRACT_VECTOR_ELT(N);
1084 case ISD::BUILD_VECTOR: return visitBUILD_VECTOR(N);
1085 case ISD::CONCAT_VECTORS: return visitCONCAT_VECTORS(N);
1086 case ISD::VECTOR_SHUFFLE: return visitVECTOR_SHUFFLE(N);
1087 case ISD::MEMBARRIER: return visitMEMBARRIER(N);
1092 SDValue DAGCombiner::combine(SDNode *N) {
1093 SDValue RV = visit(N);
1095 // If nothing happened, try a target-specific DAG combine.
1096 if (RV.getNode() == 0) {
1097 assert(N->getOpcode() != ISD::DELETED_NODE &&
1098 "Node was deleted but visit returned NULL!");
1100 if (N->getOpcode() >= ISD::BUILTIN_OP_END ||
1101 TLI.hasTargetDAGCombine((ISD::NodeType)N->getOpcode())) {
1103 // Expose the DAG combiner to the target combiner impls.
1104 TargetLowering::DAGCombinerInfo
1105 DagCombineInfo(DAG, !LegalTypes, !LegalOperations, false, this);
1107 RV = TLI.PerformDAGCombine(N, DagCombineInfo);
1111 // If nothing happened still, try promoting the operation.
1112 if (RV.getNode() == 0) {
1113 switch (N->getOpcode()) {
1121 RV = PromoteIntBinOp(SDValue(N, 0));
1126 RV = PromoteIntShiftOp(SDValue(N, 0));
1128 case ISD::SIGN_EXTEND:
1129 case ISD::ZERO_EXTEND:
1130 case ISD::ANY_EXTEND:
1131 RV = PromoteExtend(SDValue(N, 0));
1134 if (PromoteLoad(SDValue(N, 0)))
1140 // If N is a commutative binary node, try commuting it to enable more
1142 if (RV.getNode() == 0 &&
1143 SelectionDAG::isCommutativeBinOp(N->getOpcode()) &&
1144 N->getNumValues() == 1) {
1145 SDValue N0 = N->getOperand(0);
1146 SDValue N1 = N->getOperand(1);
1148 // Constant operands are canonicalized to RHS.
1149 if (isa<ConstantSDNode>(N0) || !isa<ConstantSDNode>(N1)) {
1150 SDValue Ops[] = { N1, N0 };
1151 SDNode *CSENode = DAG.getNodeIfExists(N->getOpcode(), N->getVTList(),
1154 return SDValue(CSENode, 0);
1161 /// getInputChainForNode - Given a node, return its input chain if it has one,
1162 /// otherwise return a null sd operand.
1163 static SDValue getInputChainForNode(SDNode *N) {
1164 if (unsigned NumOps = N->getNumOperands()) {
1165 if (N->getOperand(0).getValueType() == MVT::Other)
1166 return N->getOperand(0);
1167 else if (N->getOperand(NumOps-1).getValueType() == MVT::Other)
1168 return N->getOperand(NumOps-1);
1169 for (unsigned i = 1; i < NumOps-1; ++i)
1170 if (N->getOperand(i).getValueType() == MVT::Other)
1171 return N->getOperand(i);
1176 SDValue DAGCombiner::visitTokenFactor(SDNode *N) {
1177 // If N has two operands, where one has an input chain equal to the other,
1178 // the 'other' chain is redundant.
1179 if (N->getNumOperands() == 2) {
1180 if (getInputChainForNode(N->getOperand(0).getNode()) == N->getOperand(1))
1181 return N->getOperand(0);
1182 if (getInputChainForNode(N->getOperand(1).getNode()) == N->getOperand(0))
1183 return N->getOperand(1);
1186 SmallVector<SDNode *, 8> TFs; // List of token factors to visit.
1187 SmallVector<SDValue, 8> Ops; // Ops for replacing token factor.
1188 SmallPtrSet<SDNode*, 16> SeenOps;
1189 bool Changed = false; // If we should replace this token factor.
1191 // Start out with this token factor.
1194 // Iterate through token factors. The TFs grows when new token factors are
1196 for (unsigned i = 0; i < TFs.size(); ++i) {
1197 SDNode *TF = TFs[i];
1199 // Check each of the operands.
1200 for (unsigned i = 0, ie = TF->getNumOperands(); i != ie; ++i) {
1201 SDValue Op = TF->getOperand(i);
1203 switch (Op.getOpcode()) {
1204 case ISD::EntryToken:
1205 // Entry tokens don't need to be added to the list. They are
1210 case ISD::TokenFactor:
1211 if (Op.hasOneUse() &&
1212 std::find(TFs.begin(), TFs.end(), Op.getNode()) == TFs.end()) {
1213 // Queue up for processing.
1214 TFs.push_back(Op.getNode());
1215 // Clean up in case the token factor is removed.
1216 AddToWorkList(Op.getNode());
1223 // Only add if it isn't already in the list.
1224 if (SeenOps.insert(Op.getNode()))
1235 // If we've change things around then replace token factor.
1238 // The entry token is the only possible outcome.
1239 Result = DAG.getEntryNode();
1241 // New and improved token factor.
1242 Result = DAG.getNode(ISD::TokenFactor, N->getDebugLoc(),
1243 MVT::Other, &Ops[0], Ops.size());
1246 // Don't add users to work list.
1247 return CombineTo(N, Result, false);
1253 /// MERGE_VALUES can always be eliminated.
1254 SDValue DAGCombiner::visitMERGE_VALUES(SDNode *N) {
1255 WorkListRemover DeadNodes(*this);
1256 // Replacing results may cause a different MERGE_VALUES to suddenly
1257 // be CSE'd with N, and carry its uses with it. Iterate until no
1258 // uses remain, to ensure that the node can be safely deleted.
1260 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
1261 DAG.ReplaceAllUsesOfValueWith(SDValue(N, i), N->getOperand(i),
1263 } while (!N->use_empty());
1264 removeFromWorkList(N);
1266 return SDValue(N, 0); // Return N so it doesn't get rechecked!
1270 SDValue combineShlAddConstant(DebugLoc DL, SDValue N0, SDValue N1,
1271 SelectionDAG &DAG) {
1272 EVT VT = N0.getValueType();
1273 SDValue N00 = N0.getOperand(0);
1274 SDValue N01 = N0.getOperand(1);
1275 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N01);
1277 if (N01C && N00.getOpcode() == ISD::ADD && N00.getNode()->hasOneUse() &&
1278 isa<ConstantSDNode>(N00.getOperand(1))) {
1279 // fold (add (shl (add x, c1), c2), ) -> (add (add (shl x, c2), c1<<c2), )
1280 N0 = DAG.getNode(ISD::ADD, N0.getDebugLoc(), VT,
1281 DAG.getNode(ISD::SHL, N00.getDebugLoc(), VT,
1282 N00.getOperand(0), N01),
1283 DAG.getNode(ISD::SHL, N01.getDebugLoc(), VT,
1284 N00.getOperand(1), N01));
1285 return DAG.getNode(ISD::ADD, DL, VT, N0, N1);
1291 SDValue DAGCombiner::visitADD(SDNode *N) {
1292 SDValue N0 = N->getOperand(0);
1293 SDValue N1 = N->getOperand(1);
1294 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1295 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1296 EVT VT = N0.getValueType();
1299 if (VT.isVector()) {
1300 SDValue FoldedVOp = SimplifyVBinOp(N);
1301 if (FoldedVOp.getNode()) return FoldedVOp;
1304 // fold (add x, undef) -> undef
1305 if (N0.getOpcode() == ISD::UNDEF)
1307 if (N1.getOpcode() == ISD::UNDEF)
1309 // fold (add c1, c2) -> c1+c2
1311 return DAG.FoldConstantArithmetic(ISD::ADD, VT, N0C, N1C);
1312 // canonicalize constant to RHS
1314 return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N1, N0);
1315 // fold (add x, 0) -> x
1316 if (N1C && N1C->isNullValue())
1318 // fold (add Sym, c) -> Sym+c
1319 if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(N0))
1320 if (!LegalOperations && TLI.isOffsetFoldingLegal(GA) && N1C &&
1321 GA->getOpcode() == ISD::GlobalAddress)
1322 return DAG.getGlobalAddress(GA->getGlobal(), N1C->getDebugLoc(), VT,
1324 (uint64_t)N1C->getSExtValue());
1325 // fold ((c1-A)+c2) -> (c1+c2)-A
1326 if (N1C && N0.getOpcode() == ISD::SUB)
1327 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getOperand(0)))
1328 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT,
1329 DAG.getConstant(N1C->getAPIntValue()+
1330 N0C->getAPIntValue(), VT),
1333 SDValue RADD = ReassociateOps(ISD::ADD, N->getDebugLoc(), N0, N1);
1334 if (RADD.getNode() != 0)
1336 // fold ((0-A) + B) -> B-A
1337 if (N0.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N0.getOperand(0)) &&
1338 cast<ConstantSDNode>(N0.getOperand(0))->isNullValue())
1339 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N1, N0.getOperand(1));
1340 // fold (A + (0-B)) -> A-B
1341 if (N1.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N1.getOperand(0)) &&
1342 cast<ConstantSDNode>(N1.getOperand(0))->isNullValue())
1343 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0, N1.getOperand(1));
1344 // fold (A+(B-A)) -> B
1345 if (N1.getOpcode() == ISD::SUB && N0 == N1.getOperand(1))
1346 return N1.getOperand(0);
1347 // fold ((B-A)+A) -> B
1348 if (N0.getOpcode() == ISD::SUB && N1 == N0.getOperand(1))
1349 return N0.getOperand(0);
1350 // fold (A+(B-(A+C))) to (B-C)
1351 if (N1.getOpcode() == ISD::SUB && N1.getOperand(1).getOpcode() == ISD::ADD &&
1352 N0 == N1.getOperand(1).getOperand(0))
1353 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N1.getOperand(0),
1354 N1.getOperand(1).getOperand(1));
1355 // fold (A+(B-(C+A))) to (B-C)
1356 if (N1.getOpcode() == ISD::SUB && N1.getOperand(1).getOpcode() == ISD::ADD &&
1357 N0 == N1.getOperand(1).getOperand(1))
1358 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N1.getOperand(0),
1359 N1.getOperand(1).getOperand(0));
1360 // fold (A+((B-A)+or-C)) to (B+or-C)
1361 if ((N1.getOpcode() == ISD::SUB || N1.getOpcode() == ISD::ADD) &&
1362 N1.getOperand(0).getOpcode() == ISD::SUB &&
1363 N0 == N1.getOperand(0).getOperand(1))
1364 return DAG.getNode(N1.getOpcode(), N->getDebugLoc(), VT,
1365 N1.getOperand(0).getOperand(0), N1.getOperand(1));
1367 // fold (A-B)+(C-D) to (A+C)-(B+D) when A or C is constant
1368 if (N0.getOpcode() == ISD::SUB && N1.getOpcode() == ISD::SUB) {
1369 SDValue N00 = N0.getOperand(0);
1370 SDValue N01 = N0.getOperand(1);
1371 SDValue N10 = N1.getOperand(0);
1372 SDValue N11 = N1.getOperand(1);
1374 if (isa<ConstantSDNode>(N00) || isa<ConstantSDNode>(N10))
1375 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT,
1376 DAG.getNode(ISD::ADD, N0.getDebugLoc(), VT, N00, N10),
1377 DAG.getNode(ISD::ADD, N1.getDebugLoc(), VT, N01, N11));
1380 if (!VT.isVector() && SimplifyDemandedBits(SDValue(N, 0)))
1381 return SDValue(N, 0);
1383 // fold (a+b) -> (a|b) iff a and b share no bits.
1384 if (VT.isInteger() && !VT.isVector()) {
1385 APInt LHSZero, LHSOne;
1386 APInt RHSZero, RHSOne;
1387 APInt Mask = APInt::getAllOnesValue(VT.getScalarType().getSizeInBits());
1388 DAG.ComputeMaskedBits(N0, Mask, LHSZero, LHSOne);
1390 if (LHSZero.getBoolValue()) {
1391 DAG.ComputeMaskedBits(N1, Mask, RHSZero, RHSOne);
1393 // If all possibly-set bits on the LHS are clear on the RHS, return an OR.
1394 // If all possibly-set bits on the RHS are clear on the LHS, return an OR.
1395 if ((RHSZero & (~LHSZero & Mask)) == (~LHSZero & Mask) ||
1396 (LHSZero & (~RHSZero & Mask)) == (~RHSZero & Mask))
1397 return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N0, N1);
1401 // fold (add (shl (add x, c1), c2), ) -> (add (add (shl x, c2), c1<<c2), )
1402 if (N0.getOpcode() == ISD::SHL && N0.getNode()->hasOneUse()) {
1403 SDValue Result = combineShlAddConstant(N->getDebugLoc(), N0, N1, DAG);
1404 if (Result.getNode()) return Result;
1406 if (N1.getOpcode() == ISD::SHL && N1.getNode()->hasOneUse()) {
1407 SDValue Result = combineShlAddConstant(N->getDebugLoc(), N1, N0, DAG);
1408 if (Result.getNode()) return Result;
1411 // fold (add x, shl(0 - y, n)) -> sub(x, shl(y, n))
1412 if (N1.getOpcode() == ISD::SHL &&
1413 N1.getOperand(0).getOpcode() == ISD::SUB)
1414 if (ConstantSDNode *C =
1415 dyn_cast<ConstantSDNode>(N1.getOperand(0).getOperand(0)))
1416 if (C->getAPIntValue() == 0)
1417 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0,
1418 DAG.getNode(ISD::SHL, N->getDebugLoc(), VT,
1419 N1.getOperand(0).getOperand(1),
1421 if (N0.getOpcode() == ISD::SHL &&
1422 N0.getOperand(0).getOpcode() == ISD::SUB)
1423 if (ConstantSDNode *C =
1424 dyn_cast<ConstantSDNode>(N0.getOperand(0).getOperand(0)))
1425 if (C->getAPIntValue() == 0)
1426 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N1,
1427 DAG.getNode(ISD::SHL, N->getDebugLoc(), VT,
1428 N0.getOperand(0).getOperand(1),
1431 if (N1.getOpcode() == ISD::AND) {
1432 SDValue AndOp0 = N1.getOperand(0);
1433 ConstantSDNode *AndOp1 = dyn_cast<ConstantSDNode>(N1->getOperand(1));
1434 unsigned NumSignBits = DAG.ComputeNumSignBits(AndOp0);
1435 unsigned DestBits = VT.getScalarType().getSizeInBits();
1437 // (add z, (and (sbbl x, x), 1)) -> (sub z, (sbbl x, x))
1438 // and similar xforms where the inner op is either ~0 or 0.
1439 if (NumSignBits == DestBits && AndOp1 && AndOp1->isOne()) {
1440 DebugLoc DL = N->getDebugLoc();
1441 return DAG.getNode(ISD::SUB, DL, VT, N->getOperand(0), AndOp0);
1445 // add (sext i1), X -> sub X, (zext i1)
1446 if (N0.getOpcode() == ISD::SIGN_EXTEND &&
1447 N0.getOperand(0).getValueType() == MVT::i1 &&
1448 !TLI.isOperationLegal(ISD::SIGN_EXTEND, MVT::i1)) {
1449 DebugLoc DL = N->getDebugLoc();
1450 SDValue ZExt = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, N0.getOperand(0));
1451 return DAG.getNode(ISD::SUB, DL, VT, N1, ZExt);
1457 SDValue DAGCombiner::visitADDC(SDNode *N) {
1458 SDValue N0 = N->getOperand(0);
1459 SDValue N1 = N->getOperand(1);
1460 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1461 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1462 EVT VT = N0.getValueType();
1464 // If the flag result is dead, turn this into an ADD.
1465 if (N->hasNUsesOfValue(0, 1))
1466 return CombineTo(N, DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N1, N0),
1467 DAG.getNode(ISD::CARRY_FALSE,
1468 N->getDebugLoc(), MVT::Glue));
1470 // canonicalize constant to RHS.
1472 return DAG.getNode(ISD::ADDC, N->getDebugLoc(), N->getVTList(), N1, N0);
1474 // fold (addc x, 0) -> x + no carry out
1475 if (N1C && N1C->isNullValue())
1476 return CombineTo(N, N0, DAG.getNode(ISD::CARRY_FALSE,
1477 N->getDebugLoc(), MVT::Glue));
1479 // fold (addc a, b) -> (or a, b), CARRY_FALSE iff a and b share no bits.
1480 APInt LHSZero, LHSOne;
1481 APInt RHSZero, RHSOne;
1482 APInt Mask = APInt::getAllOnesValue(VT.getScalarType().getSizeInBits());
1483 DAG.ComputeMaskedBits(N0, Mask, LHSZero, LHSOne);
1485 if (LHSZero.getBoolValue()) {
1486 DAG.ComputeMaskedBits(N1, Mask, RHSZero, RHSOne);
1488 // If all possibly-set bits on the LHS are clear on the RHS, return an OR.
1489 // If all possibly-set bits on the RHS are clear on the LHS, return an OR.
1490 if ((RHSZero & (~LHSZero & Mask)) == (~LHSZero & Mask) ||
1491 (LHSZero & (~RHSZero & Mask)) == (~RHSZero & Mask))
1492 return CombineTo(N, DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N0, N1),
1493 DAG.getNode(ISD::CARRY_FALSE,
1494 N->getDebugLoc(), MVT::Glue));
1500 SDValue DAGCombiner::visitADDE(SDNode *N) {
1501 SDValue N0 = N->getOperand(0);
1502 SDValue N1 = N->getOperand(1);
1503 SDValue CarryIn = N->getOperand(2);
1504 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1505 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1507 // canonicalize constant to RHS
1509 return DAG.getNode(ISD::ADDE, N->getDebugLoc(), N->getVTList(),
1512 // fold (adde x, y, false) -> (addc x, y)
1513 if (CarryIn.getOpcode() == ISD::CARRY_FALSE)
1514 return DAG.getNode(ISD::ADDC, N->getDebugLoc(), N->getVTList(), N1, N0);
1519 SDValue DAGCombiner::visitSUB(SDNode *N) {
1520 SDValue N0 = N->getOperand(0);
1521 SDValue N1 = N->getOperand(1);
1522 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getNode());
1523 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode());
1524 EVT VT = N0.getValueType();
1527 if (VT.isVector()) {
1528 SDValue FoldedVOp = SimplifyVBinOp(N);
1529 if (FoldedVOp.getNode()) return FoldedVOp;
1532 // fold (sub x, x) -> 0
1534 return DAG.getConstant(0, N->getValueType(0));
1535 // fold (sub c1, c2) -> c1-c2
1537 return DAG.FoldConstantArithmetic(ISD::SUB, VT, N0C, N1C);
1538 // fold (sub x, c) -> (add x, -c)
1540 return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N0,
1541 DAG.getConstant(-N1C->getAPIntValue(), VT));
1542 // Canonicalize (sub -1, x) -> ~x, i.e. (xor x, -1)
1543 if (N0C && N0C->isAllOnesValue())
1544 return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N1, N0);
1545 // fold (A+B)-A -> B
1546 if (N0.getOpcode() == ISD::ADD && N0.getOperand(0) == N1)
1547 return N0.getOperand(1);
1548 // fold (A+B)-B -> A
1549 if (N0.getOpcode() == ISD::ADD && N0.getOperand(1) == N1)
1550 return N0.getOperand(0);
1551 // fold ((A+(B+or-C))-B) -> A+or-C
1552 if (N0.getOpcode() == ISD::ADD &&
1553 (N0.getOperand(1).getOpcode() == ISD::SUB ||
1554 N0.getOperand(1).getOpcode() == ISD::ADD) &&
1555 N0.getOperand(1).getOperand(0) == N1)
1556 return DAG.getNode(N0.getOperand(1).getOpcode(), N->getDebugLoc(), VT,
1557 N0.getOperand(0), N0.getOperand(1).getOperand(1));
1558 // fold ((A+(C+B))-B) -> A+C
1559 if (N0.getOpcode() == ISD::ADD &&
1560 N0.getOperand(1).getOpcode() == ISD::ADD &&
1561 N0.getOperand(1).getOperand(1) == N1)
1562 return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT,
1563 N0.getOperand(0), N0.getOperand(1).getOperand(0));
1564 // fold ((A-(B-C))-C) -> A-B
1565 if (N0.getOpcode() == ISD::SUB &&
1566 N0.getOperand(1).getOpcode() == ISD::SUB &&
1567 N0.getOperand(1).getOperand(1) == N1)
1568 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT,
1569 N0.getOperand(0), N0.getOperand(1).getOperand(0));
1571 // If either operand of a sub is undef, the result is undef
1572 if (N0.getOpcode() == ISD::UNDEF)
1574 if (N1.getOpcode() == ISD::UNDEF)
1577 // If the relocation model supports it, consider symbol offsets.
1578 if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(N0))
1579 if (!LegalOperations && TLI.isOffsetFoldingLegal(GA)) {
1580 // fold (sub Sym, c) -> Sym-c
1581 if (N1C && GA->getOpcode() == ISD::GlobalAddress)
1582 return DAG.getGlobalAddress(GA->getGlobal(), N1C->getDebugLoc(), VT,
1584 (uint64_t)N1C->getSExtValue());
1585 // fold (sub Sym+c1, Sym+c2) -> c1-c2
1586 if (GlobalAddressSDNode *GB = dyn_cast<GlobalAddressSDNode>(N1))
1587 if (GA->getGlobal() == GB->getGlobal())
1588 return DAG.getConstant((uint64_t)GA->getOffset() - GB->getOffset(),
1595 SDValue DAGCombiner::visitMUL(SDNode *N) {
1596 SDValue N0 = N->getOperand(0);
1597 SDValue N1 = N->getOperand(1);
1598 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1599 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1600 EVT VT = N0.getValueType();
1603 if (VT.isVector()) {
1604 SDValue FoldedVOp = SimplifyVBinOp(N);
1605 if (FoldedVOp.getNode()) return FoldedVOp;
1608 // fold (mul x, undef) -> 0
1609 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF)
1610 return DAG.getConstant(0, VT);
1611 // fold (mul c1, c2) -> c1*c2
1613 return DAG.FoldConstantArithmetic(ISD::MUL, VT, N0C, N1C);
1614 // canonicalize constant to RHS
1616 return DAG.getNode(ISD::MUL, N->getDebugLoc(), VT, N1, N0);
1617 // fold (mul x, 0) -> 0
1618 if (N1C && N1C->isNullValue())
1620 // fold (mul x, -1) -> 0-x
1621 if (N1C && N1C->isAllOnesValue())
1622 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT,
1623 DAG.getConstant(0, VT), N0);
1624 // fold (mul x, (1 << c)) -> x << c
1625 if (N1C && N1C->getAPIntValue().isPowerOf2())
1626 return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0,
1627 DAG.getConstant(N1C->getAPIntValue().logBase2(),
1628 getShiftAmountTy()));
1629 // fold (mul x, -(1 << c)) -> -(x << c) or (-x) << c
1630 if (N1C && (-N1C->getAPIntValue()).isPowerOf2()) {
1631 unsigned Log2Val = (-N1C->getAPIntValue()).logBase2();
1632 // FIXME: If the input is something that is easily negated (e.g. a
1633 // single-use add), we should put the negate there.
1634 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT,
1635 DAG.getConstant(0, VT),
1636 DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0,
1637 DAG.getConstant(Log2Val, getShiftAmountTy())));
1639 // (mul (shl X, c1), c2) -> (mul X, c2 << c1)
1640 if (N1C && N0.getOpcode() == ISD::SHL &&
1641 isa<ConstantSDNode>(N0.getOperand(1))) {
1642 SDValue C3 = DAG.getNode(ISD::SHL, N->getDebugLoc(), VT,
1643 N1, N0.getOperand(1));
1644 AddToWorkList(C3.getNode());
1645 return DAG.getNode(ISD::MUL, N->getDebugLoc(), VT,
1646 N0.getOperand(0), C3);
1649 // Change (mul (shl X, C), Y) -> (shl (mul X, Y), C) when the shift has one
1652 SDValue Sh(0,0), Y(0,0);
1653 // Check for both (mul (shl X, C), Y) and (mul Y, (shl X, C)).
1654 if (N0.getOpcode() == ISD::SHL && isa<ConstantSDNode>(N0.getOperand(1)) &&
1655 N0.getNode()->hasOneUse()) {
1657 } else if (N1.getOpcode() == ISD::SHL &&
1658 isa<ConstantSDNode>(N1.getOperand(1)) &&
1659 N1.getNode()->hasOneUse()) {
1664 SDValue Mul = DAG.getNode(ISD::MUL, N->getDebugLoc(), VT,
1665 Sh.getOperand(0), Y);
1666 return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT,
1667 Mul, Sh.getOperand(1));
1671 // fold (mul (add x, c1), c2) -> (add (mul x, c2), c1*c2)
1672 if (N1C && N0.getOpcode() == ISD::ADD && N0.getNode()->hasOneUse() &&
1673 isa<ConstantSDNode>(N0.getOperand(1)))
1674 return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT,
1675 DAG.getNode(ISD::MUL, N0.getDebugLoc(), VT,
1676 N0.getOperand(0), N1),
1677 DAG.getNode(ISD::MUL, N1.getDebugLoc(), VT,
1678 N0.getOperand(1), N1));
1681 SDValue RMUL = ReassociateOps(ISD::MUL, N->getDebugLoc(), N0, N1);
1682 if (RMUL.getNode() != 0)
1688 SDValue DAGCombiner::visitSDIV(SDNode *N) {
1689 SDValue N0 = N->getOperand(0);
1690 SDValue N1 = N->getOperand(1);
1691 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getNode());
1692 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode());
1693 EVT VT = N->getValueType(0);
1696 if (VT.isVector()) {
1697 SDValue FoldedVOp = SimplifyVBinOp(N);
1698 if (FoldedVOp.getNode()) return FoldedVOp;
1701 // fold (sdiv c1, c2) -> c1/c2
1702 if (N0C && N1C && !N1C->isNullValue())
1703 return DAG.FoldConstantArithmetic(ISD::SDIV, VT, N0C, N1C);
1704 // fold (sdiv X, 1) -> X
1705 if (N1C && N1C->getSExtValue() == 1LL)
1707 // fold (sdiv X, -1) -> 0-X
1708 if (N1C && N1C->isAllOnesValue())
1709 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT,
1710 DAG.getConstant(0, VT), N0);
1711 // If we know the sign bits of both operands are zero, strength reduce to a
1712 // udiv instead. Handles (X&15) /s 4 -> X&15 >> 2
1713 if (!VT.isVector()) {
1714 if (DAG.SignBitIsZero(N1) && DAG.SignBitIsZero(N0))
1715 return DAG.getNode(ISD::UDIV, N->getDebugLoc(), N1.getValueType(),
1718 // fold (sdiv X, pow2) -> simple ops after legalize
1719 if (N1C && !N1C->isNullValue() && !TLI.isIntDivCheap() &&
1720 (isPowerOf2_64(N1C->getSExtValue()) ||
1721 isPowerOf2_64(-N1C->getSExtValue()))) {
1722 // If dividing by powers of two is cheap, then don't perform the following
1724 if (TLI.isPow2DivCheap())
1727 int64_t pow2 = N1C->getSExtValue();
1728 int64_t abs2 = pow2 > 0 ? pow2 : -pow2;
1729 unsigned lg2 = Log2_64(abs2);
1731 // Splat the sign bit into the register
1732 SDValue SGN = DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, N0,
1733 DAG.getConstant(VT.getSizeInBits()-1,
1734 getShiftAmountTy()));
1735 AddToWorkList(SGN.getNode());
1737 // Add (N0 < 0) ? abs2 - 1 : 0;
1738 SDValue SRL = DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, SGN,
1739 DAG.getConstant(VT.getSizeInBits() - lg2,
1740 getShiftAmountTy()));
1741 SDValue ADD = DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N0, SRL);
1742 AddToWorkList(SRL.getNode());
1743 AddToWorkList(ADD.getNode()); // Divide by pow2
1744 SDValue SRA = DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, ADD,
1745 DAG.getConstant(lg2, getShiftAmountTy()));
1747 // If we're dividing by a positive value, we're done. Otherwise, we must
1748 // negate the result.
1752 AddToWorkList(SRA.getNode());
1753 return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT,
1754 DAG.getConstant(0, VT), SRA);
1757 // if integer divide is expensive and we satisfy the requirements, emit an
1758 // alternate sequence.
1759 if (N1C && (N1C->getSExtValue() < -1 || N1C->getSExtValue() > 1) &&
1760 !TLI.isIntDivCheap()) {
1761 SDValue Op = BuildSDIV(N);
1762 if (Op.getNode()) return Op;
1766 if (N0.getOpcode() == ISD::UNDEF)
1767 return DAG.getConstant(0, VT);
1768 // X / undef -> undef
1769 if (N1.getOpcode() == ISD::UNDEF)
1775 SDValue DAGCombiner::visitUDIV(SDNode *N) {
1776 SDValue N0 = N->getOperand(0);
1777 SDValue N1 = N->getOperand(1);
1778 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getNode());
1779 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode());
1780 EVT VT = N->getValueType(0);
1783 if (VT.isVector()) {
1784 SDValue FoldedVOp = SimplifyVBinOp(N);
1785 if (FoldedVOp.getNode()) return FoldedVOp;
1788 // fold (udiv c1, c2) -> c1/c2
1789 if (N0C && N1C && !N1C->isNullValue())
1790 return DAG.FoldConstantArithmetic(ISD::UDIV, VT, N0C, N1C);
1791 // fold (udiv x, (1 << c)) -> x >>u c
1792 if (N1C && N1C->getAPIntValue().isPowerOf2())
1793 return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0,
1794 DAG.getConstant(N1C->getAPIntValue().logBase2(),
1795 getShiftAmountTy()));
1796 // fold (udiv x, (shl c, y)) -> x >>u (log2(c)+y) iff c is power of 2
1797 if (N1.getOpcode() == ISD::SHL) {
1798 if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) {
1799 if (SHC->getAPIntValue().isPowerOf2()) {
1800 EVT ADDVT = N1.getOperand(1).getValueType();
1801 SDValue Add = DAG.getNode(ISD::ADD, N->getDebugLoc(), ADDVT,
1803 DAG.getConstant(SHC->getAPIntValue()
1806 AddToWorkList(Add.getNode());
1807 return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0, Add);
1811 // fold (udiv x, c) -> alternate
1812 if (N1C && !N1C->isNullValue() && !TLI.isIntDivCheap()) {
1813 SDValue Op = BuildUDIV(N);
1814 if (Op.getNode()) return Op;
1818 if (N0.getOpcode() == ISD::UNDEF)
1819 return DAG.getConstant(0, VT);
1820 // X / undef -> undef
1821 if (N1.getOpcode() == ISD::UNDEF)
1827 SDValue DAGCombiner::visitSREM(SDNode *N) {
1828 SDValue N0 = N->getOperand(0);
1829 SDValue N1 = N->getOperand(1);
1830 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1831 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1832 EVT VT = N->getValueType(0);
1834 // fold (srem c1, c2) -> c1%c2
1835 if (N0C && N1C && !N1C->isNullValue())
1836 return DAG.FoldConstantArithmetic(ISD::SREM, VT, N0C, N1C);
1837 // If we know the sign bits of both operands are zero, strength reduce to a
1838 // urem instead. Handles (X & 0x0FFFFFFF) %s 16 -> X&15
1839 if (!VT.isVector()) {
1840 if (DAG.SignBitIsZero(N1) && DAG.SignBitIsZero(N0))
1841 return DAG.getNode(ISD::UREM, N->getDebugLoc(), VT, N0, N1);
1844 // If X/C can be simplified by the division-by-constant logic, lower
1845 // X%C to the equivalent of X-X/C*C.
1846 if (N1C && !N1C->isNullValue()) {
1847 SDValue Div = DAG.getNode(ISD::SDIV, N->getDebugLoc(), VT, N0, N1);
1848 AddToWorkList(Div.getNode());
1849 SDValue OptimizedDiv = combine(Div.getNode());
1850 if (OptimizedDiv.getNode() && OptimizedDiv.getNode() != Div.getNode()) {
1851 SDValue Mul = DAG.getNode(ISD::MUL, N->getDebugLoc(), VT,
1853 SDValue Sub = DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0, Mul);
1854 AddToWorkList(Mul.getNode());
1860 if (N0.getOpcode() == ISD::UNDEF)
1861 return DAG.getConstant(0, VT);
1862 // X % undef -> undef
1863 if (N1.getOpcode() == ISD::UNDEF)
1869 SDValue DAGCombiner::visitUREM(SDNode *N) {
1870 SDValue N0 = N->getOperand(0);
1871 SDValue N1 = N->getOperand(1);
1872 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1873 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1874 EVT VT = N->getValueType(0);
1876 // fold (urem c1, c2) -> c1%c2
1877 if (N0C && N1C && !N1C->isNullValue())
1878 return DAG.FoldConstantArithmetic(ISD::UREM, VT, N0C, N1C);
1879 // fold (urem x, pow2) -> (and x, pow2-1)
1880 if (N1C && !N1C->isNullValue() && N1C->getAPIntValue().isPowerOf2())
1881 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0,
1882 DAG.getConstant(N1C->getAPIntValue()-1,VT));
1883 // fold (urem x, (shl pow2, y)) -> (and x, (add (shl pow2, y), -1))
1884 if (N1.getOpcode() == ISD::SHL) {
1885 if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) {
1886 if (SHC->getAPIntValue().isPowerOf2()) {
1888 DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N1,
1889 DAG.getConstant(APInt::getAllOnesValue(VT.getSizeInBits()),
1891 AddToWorkList(Add.getNode());
1892 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0, Add);
1897 // If X/C can be simplified by the division-by-constant logic, lower
1898 // X%C to the equivalent of X-X/C*C.
1899 if (N1C && !N1C->isNullValue()) {
1900 SDValue Div = DAG.getNode(ISD::UDIV, N->getDebugLoc(), VT, N0, N1);
1901 AddToWorkList(Div.getNode());
1902 SDValue OptimizedDiv = combine(Div.getNode());
1903 if (OptimizedDiv.getNode() && OptimizedDiv.getNode() != Div.getNode()) {
1904 SDValue Mul = DAG.getNode(ISD::MUL, N->getDebugLoc(), VT,
1906 SDValue Sub = DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0, Mul);
1907 AddToWorkList(Mul.getNode());
1913 if (N0.getOpcode() == ISD::UNDEF)
1914 return DAG.getConstant(0, VT);
1915 // X % undef -> undef
1916 if (N1.getOpcode() == ISD::UNDEF)
1922 SDValue DAGCombiner::visitMULHS(SDNode *N) {
1923 SDValue N0 = N->getOperand(0);
1924 SDValue N1 = N->getOperand(1);
1925 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1926 EVT VT = N->getValueType(0);
1927 DebugLoc DL = N->getDebugLoc();
1929 // fold (mulhs x, 0) -> 0
1930 if (N1C && N1C->isNullValue())
1932 // fold (mulhs x, 1) -> (sra x, size(x)-1)
1933 if (N1C && N1C->getAPIntValue() == 1)
1934 return DAG.getNode(ISD::SRA, N->getDebugLoc(), N0.getValueType(), N0,
1935 DAG.getConstant(N0.getValueType().getSizeInBits() - 1,
1936 getShiftAmountTy()));
1937 // fold (mulhs x, undef) -> 0
1938 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF)
1939 return DAG.getConstant(0, VT);
1941 // If the type twice as wide is legal, transform the mulhs to a wider multiply
1943 if (VT.isSimple() && !VT.isVector()) {
1944 MVT Simple = VT.getSimpleVT();
1945 unsigned SimpleSize = Simple.getSizeInBits();
1946 EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), SimpleSize*2);
1947 if (TLI.isOperationLegal(ISD::MUL, NewVT)) {
1948 N0 = DAG.getNode(ISD::SIGN_EXTEND, DL, NewVT, N0);
1949 N1 = DAG.getNode(ISD::SIGN_EXTEND, DL, NewVT, N1);
1950 N1 = DAG.getNode(ISD::MUL, DL, NewVT, N0, N1);
1951 N1 = DAG.getNode(ISD::SRL, DL, NewVT, N1,
1952 DAG.getConstant(SimpleSize, getShiftAmountTy()));
1953 return DAG.getNode(ISD::TRUNCATE, DL, VT, N1);
1960 SDValue DAGCombiner::visitMULHU(SDNode *N) {
1961 SDValue N0 = N->getOperand(0);
1962 SDValue N1 = N->getOperand(1);
1963 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1964 EVT VT = N->getValueType(0);
1965 DebugLoc DL = N->getDebugLoc();
1967 // fold (mulhu x, 0) -> 0
1968 if (N1C && N1C->isNullValue())
1970 // fold (mulhu x, 1) -> 0
1971 if (N1C && N1C->getAPIntValue() == 1)
1972 return DAG.getConstant(0, N0.getValueType());
1973 // fold (mulhu x, undef) -> 0
1974 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF)
1975 return DAG.getConstant(0, VT);
1977 // If the type twice as wide is legal, transform the mulhu to a wider multiply
1979 if (VT.isSimple() && !VT.isVector()) {
1980 MVT Simple = VT.getSimpleVT();
1981 unsigned SimpleSize = Simple.getSizeInBits();
1982 EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), SimpleSize*2);
1983 if (TLI.isOperationLegal(ISD::MUL, NewVT)) {
1984 N0 = DAG.getNode(ISD::ZERO_EXTEND, DL, NewVT, N0);
1985 N1 = DAG.getNode(ISD::ZERO_EXTEND, DL, NewVT, N1);
1986 N1 = DAG.getNode(ISD::MUL, DL, NewVT, N0, N1);
1987 N1 = DAG.getNode(ISD::SRL, DL, NewVT, N1,
1988 DAG.getConstant(SimpleSize, getShiftAmountTy()));
1989 return DAG.getNode(ISD::TRUNCATE, DL, VT, N1);
1996 /// SimplifyNodeWithTwoResults - Perform optimizations common to nodes that
1997 /// compute two values. LoOp and HiOp give the opcodes for the two computations
1998 /// that are being performed. Return true if a simplification was made.
2000 SDValue DAGCombiner::SimplifyNodeWithTwoResults(SDNode *N, unsigned LoOp,
2002 // If the high half is not needed, just compute the low half.
2003 bool HiExists = N->hasAnyUseOfValue(1);
2005 (!LegalOperations ||
2006 TLI.isOperationLegal(LoOp, N->getValueType(0)))) {
2007 SDValue Res = DAG.getNode(LoOp, N->getDebugLoc(), N->getValueType(0),
2008 N->op_begin(), N->getNumOperands());
2009 return CombineTo(N, Res, Res);
2012 // If the low half is not needed, just compute the high half.
2013 bool LoExists = N->hasAnyUseOfValue(0);
2015 (!LegalOperations ||
2016 TLI.isOperationLegal(HiOp, N->getValueType(1)))) {
2017 SDValue Res = DAG.getNode(HiOp, N->getDebugLoc(), N->getValueType(1),
2018 N->op_begin(), N->getNumOperands());
2019 return CombineTo(N, Res, Res);
2022 // If both halves are used, return as it is.
2023 if (LoExists && HiExists)
2026 // If the two computed results can be simplified separately, separate them.
2028 SDValue Lo = DAG.getNode(LoOp, N->getDebugLoc(), N->getValueType(0),
2029 N->op_begin(), N->getNumOperands());
2030 AddToWorkList(Lo.getNode());
2031 SDValue LoOpt = combine(Lo.getNode());
2032 if (LoOpt.getNode() && LoOpt.getNode() != Lo.getNode() &&
2033 (!LegalOperations ||
2034 TLI.isOperationLegal(LoOpt.getOpcode(), LoOpt.getValueType())))
2035 return CombineTo(N, LoOpt, LoOpt);
2039 SDValue Hi = DAG.getNode(HiOp, N->getDebugLoc(), N->getValueType(1),
2040 N->op_begin(), N->getNumOperands());
2041 AddToWorkList(Hi.getNode());
2042 SDValue HiOpt = combine(Hi.getNode());
2043 if (HiOpt.getNode() && HiOpt != Hi &&
2044 (!LegalOperations ||
2045 TLI.isOperationLegal(HiOpt.getOpcode(), HiOpt.getValueType())))
2046 return CombineTo(N, HiOpt, HiOpt);
2052 SDValue DAGCombiner::visitSMUL_LOHI(SDNode *N) {
2053 SDValue Res = SimplifyNodeWithTwoResults(N, ISD::MUL, ISD::MULHS);
2054 if (Res.getNode()) return Res;
2056 EVT VT = N->getValueType(0);
2057 DebugLoc DL = N->getDebugLoc();
2059 // If the type twice as wide is legal, transform the mulhu to a wider multiply
2061 if (VT.isSimple() && !VT.isVector()) {
2062 MVT Simple = VT.getSimpleVT();
2063 unsigned SimpleSize = Simple.getSizeInBits();
2064 EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), SimpleSize*2);
2065 if (TLI.isOperationLegal(ISD::MUL, NewVT)) {
2066 SDValue Lo = DAG.getNode(ISD::SIGN_EXTEND, DL, NewVT, N->getOperand(0));
2067 SDValue Hi = DAG.getNode(ISD::SIGN_EXTEND, DL, NewVT, N->getOperand(1));
2068 Lo = DAG.getNode(ISD::MUL, DL, NewVT, Lo, Hi);
2069 // Compute the high part as N1.
2070 Hi = DAG.getNode(ISD::SRL, DL, NewVT, Lo,
2071 DAG.getConstant(SimpleSize, getShiftAmountTy()));
2072 Hi = DAG.getNode(ISD::TRUNCATE, DL, VT, Hi);
2073 // Compute the low part as N0.
2074 Lo = DAG.getNode(ISD::TRUNCATE, DL, VT, Lo);
2075 return CombineTo(N, Lo, Hi);
2082 SDValue DAGCombiner::visitUMUL_LOHI(SDNode *N) {
2083 SDValue Res = SimplifyNodeWithTwoResults(N, ISD::MUL, ISD::MULHU);
2084 if (Res.getNode()) return Res;
2086 EVT VT = N->getValueType(0);
2087 DebugLoc DL = N->getDebugLoc();
2089 // If the type twice as wide is legal, transform the mulhu to a wider multiply
2091 if (VT.isSimple() && !VT.isVector()) {
2092 MVT Simple = VT.getSimpleVT();
2093 unsigned SimpleSize = Simple.getSizeInBits();
2094 EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), SimpleSize*2);
2095 if (TLI.isOperationLegal(ISD::MUL, NewVT)) {
2096 SDValue Lo = DAG.getNode(ISD::ZERO_EXTEND, DL, NewVT, N->getOperand(0));
2097 SDValue Hi = DAG.getNode(ISD::ZERO_EXTEND, DL, NewVT, N->getOperand(1));
2098 Lo = DAG.getNode(ISD::MUL, DL, NewVT, Lo, Hi);
2099 // Compute the high part as N1.
2100 Hi = DAG.getNode(ISD::SRL, DL, NewVT, Lo,
2101 DAG.getConstant(SimpleSize, getShiftAmountTy()));
2102 Hi = DAG.getNode(ISD::TRUNCATE, DL, VT, Hi);
2103 // Compute the low part as N0.
2104 Lo = DAG.getNode(ISD::TRUNCATE, DL, VT, Lo);
2105 return CombineTo(N, Lo, Hi);
2112 SDValue DAGCombiner::visitSDIVREM(SDNode *N) {
2113 SDValue Res = SimplifyNodeWithTwoResults(N, ISD::SDIV, ISD::SREM);
2114 if (Res.getNode()) return Res;
2119 SDValue DAGCombiner::visitUDIVREM(SDNode *N) {
2120 SDValue Res = SimplifyNodeWithTwoResults(N, ISD::UDIV, ISD::UREM);
2121 if (Res.getNode()) return Res;
2126 /// SimplifyBinOpWithSameOpcodeHands - If this is a binary operator with
2127 /// two operands of the same opcode, try to simplify it.
2128 SDValue DAGCombiner::SimplifyBinOpWithSameOpcodeHands(SDNode *N) {
2129 SDValue N0 = N->getOperand(0), N1 = N->getOperand(1);
2130 EVT VT = N0.getValueType();
2131 assert(N0.getOpcode() == N1.getOpcode() && "Bad input!");
2133 // Bail early if none of these transforms apply.
2134 if (N0.getNode()->getNumOperands() == 0) return SDValue();
2136 // For each of OP in AND/OR/XOR:
2137 // fold (OP (zext x), (zext y)) -> (zext (OP x, y))
2138 // fold (OP (sext x), (sext y)) -> (sext (OP x, y))
2139 // fold (OP (aext x), (aext y)) -> (aext (OP x, y))
2140 // fold (OP (trunc x), (trunc y)) -> (trunc (OP x, y)) (if trunc isn't free)
2142 // do not sink logical op inside of a vector extend, since it may combine
2144 EVT Op0VT = N0.getOperand(0).getValueType();
2145 if ((N0.getOpcode() == ISD::ZERO_EXTEND ||
2146 N0.getOpcode() == ISD::SIGN_EXTEND ||
2147 // Avoid infinite looping with PromoteIntBinOp.
2148 (N0.getOpcode() == ISD::ANY_EXTEND &&
2149 (!LegalTypes || TLI.isTypeDesirableForOp(N->getOpcode(), Op0VT))) ||
2150 (N0.getOpcode() == ISD::TRUNCATE &&
2151 (!TLI.isZExtFree(VT, Op0VT) ||
2152 !TLI.isTruncateFree(Op0VT, VT)) &&
2153 TLI.isTypeLegal(Op0VT))) &&
2155 Op0VT == N1.getOperand(0).getValueType() &&
2156 (!LegalOperations || TLI.isOperationLegal(N->getOpcode(), Op0VT))) {
2157 SDValue ORNode = DAG.getNode(N->getOpcode(), N0.getDebugLoc(),
2158 N0.getOperand(0).getValueType(),
2159 N0.getOperand(0), N1.getOperand(0));
2160 AddToWorkList(ORNode.getNode());
2161 return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT, ORNode);
2164 // For each of OP in SHL/SRL/SRA/AND...
2165 // fold (and (OP x, z), (OP y, z)) -> (OP (and x, y), z)
2166 // fold (or (OP x, z), (OP y, z)) -> (OP (or x, y), z)
2167 // fold (xor (OP x, z), (OP y, z)) -> (OP (xor x, y), z)
2168 if ((N0.getOpcode() == ISD::SHL || N0.getOpcode() == ISD::SRL ||
2169 N0.getOpcode() == ISD::SRA || N0.getOpcode() == ISD::AND) &&
2170 N0.getOperand(1) == N1.getOperand(1)) {
2171 SDValue ORNode = DAG.getNode(N->getOpcode(), N0.getDebugLoc(),
2172 N0.getOperand(0).getValueType(),
2173 N0.getOperand(0), N1.getOperand(0));
2174 AddToWorkList(ORNode.getNode());
2175 return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT,
2176 ORNode, N0.getOperand(1));
2182 SDValue DAGCombiner::visitAND(SDNode *N) {
2183 SDValue N0 = N->getOperand(0);
2184 SDValue N1 = N->getOperand(1);
2185 SDValue LL, LR, RL, RR, CC0, CC1;
2186 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
2187 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
2188 EVT VT = N1.getValueType();
2189 unsigned BitWidth = VT.getScalarType().getSizeInBits();
2192 if (VT.isVector()) {
2193 SDValue FoldedVOp = SimplifyVBinOp(N);
2194 if (FoldedVOp.getNode()) return FoldedVOp;
2197 // fold (and x, undef) -> 0
2198 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF)
2199 return DAG.getConstant(0, VT);
2200 // fold (and c1, c2) -> c1&c2
2202 return DAG.FoldConstantArithmetic(ISD::AND, VT, N0C, N1C);
2203 // canonicalize constant to RHS
2205 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N1, N0);
2206 // fold (and x, -1) -> x
2207 if (N1C && N1C->isAllOnesValue())
2209 // if (and x, c) is known to be zero, return 0
2210 if (N1C && DAG.MaskedValueIsZero(SDValue(N, 0),
2211 APInt::getAllOnesValue(BitWidth)))
2212 return DAG.getConstant(0, VT);
2214 SDValue RAND = ReassociateOps(ISD::AND, N->getDebugLoc(), N0, N1);
2215 if (RAND.getNode() != 0)
2217 // fold (and (or x, C), D) -> D if (C & D) == D
2218 if (N1C && N0.getOpcode() == ISD::OR)
2219 if (ConstantSDNode *ORI = dyn_cast<ConstantSDNode>(N0.getOperand(1)))
2220 if ((ORI->getAPIntValue() & N1C->getAPIntValue()) == N1C->getAPIntValue())
2222 // fold (and (any_ext V), c) -> (zero_ext V) if 'and' only clears top bits.
2223 if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) {
2224 SDValue N0Op0 = N0.getOperand(0);
2225 APInt Mask = ~N1C->getAPIntValue();
2226 Mask = Mask.trunc(N0Op0.getValueSizeInBits());
2227 if (DAG.MaskedValueIsZero(N0Op0, Mask)) {
2228 SDValue Zext = DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(),
2229 N0.getValueType(), N0Op0);
2231 // Replace uses of the AND with uses of the Zero extend node.
2234 // We actually want to replace all uses of the any_extend with the
2235 // zero_extend, to avoid duplicating things. This will later cause this
2236 // AND to be folded.
2237 CombineTo(N0.getNode(), Zext);
2238 return SDValue(N, 0); // Return N so it doesn't get rechecked!
2241 // fold (and (setcc x), (setcc y)) -> (setcc (and x, y))
2242 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){
2243 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get();
2244 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get();
2246 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 &&
2247 LL.getValueType().isInteger()) {
2248 // fold (and (seteq X, 0), (seteq Y, 0)) -> (seteq (or X, Y), 0)
2249 if (cast<ConstantSDNode>(LR)->isNullValue() && Op1 == ISD::SETEQ) {
2250 SDValue ORNode = DAG.getNode(ISD::OR, N0.getDebugLoc(),
2251 LR.getValueType(), LL, RL);
2252 AddToWorkList(ORNode.getNode());
2253 return DAG.getSetCC(N->getDebugLoc(), VT, ORNode, LR, Op1);
2255 // fold (and (seteq X, -1), (seteq Y, -1)) -> (seteq (and X, Y), -1)
2256 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETEQ) {
2257 SDValue ANDNode = DAG.getNode(ISD::AND, N0.getDebugLoc(),
2258 LR.getValueType(), LL, RL);
2259 AddToWorkList(ANDNode.getNode());
2260 return DAG.getSetCC(N->getDebugLoc(), VT, ANDNode, LR, Op1);
2262 // fold (and (setgt X, -1), (setgt Y, -1)) -> (setgt (or X, Y), -1)
2263 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETGT) {
2264 SDValue ORNode = DAG.getNode(ISD::OR, N0.getDebugLoc(),
2265 LR.getValueType(), LL, RL);
2266 AddToWorkList(ORNode.getNode());
2267 return DAG.getSetCC(N->getDebugLoc(), VT, ORNode, LR, Op1);
2270 // canonicalize equivalent to ll == rl
2271 if (LL == RR && LR == RL) {
2272 Op1 = ISD::getSetCCSwappedOperands(Op1);
2275 if (LL == RL && LR == RR) {
2276 bool isInteger = LL.getValueType().isInteger();
2277 ISD::CondCode Result = ISD::getSetCCAndOperation(Op0, Op1, isInteger);
2278 if (Result != ISD::SETCC_INVALID &&
2279 (!LegalOperations || TLI.isCondCodeLegal(Result, LL.getValueType())))
2280 return DAG.getSetCC(N->getDebugLoc(), N0.getValueType(),
2285 // Simplify: (and (op x...), (op y...)) -> (op (and x, y))
2286 if (N0.getOpcode() == N1.getOpcode()) {
2287 SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N);
2288 if (Tmp.getNode()) return Tmp;
2291 // fold (and (sign_extend_inreg x, i16 to i32), 1) -> (and x, 1)
2292 // fold (and (sra)) -> (and (srl)) when possible.
2293 if (!VT.isVector() &&
2294 SimplifyDemandedBits(SDValue(N, 0)))
2295 return SDValue(N, 0);
2297 // fold (zext_inreg (extload x)) -> (zextload x)
2298 if (ISD::isEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode())) {
2299 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
2300 EVT MemVT = LN0->getMemoryVT();
2301 // If we zero all the possible extended bits, then we can turn this into
2302 // a zextload if we are running before legalize or the operation is legal.
2303 unsigned BitWidth = N1.getValueType().getScalarType().getSizeInBits();
2304 if (DAG.MaskedValueIsZero(N1, APInt::getHighBitsSet(BitWidth,
2305 BitWidth - MemVT.getScalarType().getSizeInBits())) &&
2306 ((!LegalOperations && !LN0->isVolatile()) ||
2307 TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT))) {
2308 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getDebugLoc(),
2309 LN0->getChain(), LN0->getBasePtr(),
2310 LN0->getPointerInfo(), MemVT,
2311 LN0->isVolatile(), LN0->isNonTemporal(),
2312 LN0->getAlignment());
2314 CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1));
2315 return SDValue(N, 0); // Return N so it doesn't get rechecked!
2318 // fold (zext_inreg (sextload x)) -> (zextload x) iff load has one use
2319 if (ISD::isSEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) &&
2321 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
2322 EVT MemVT = LN0->getMemoryVT();
2323 // If we zero all the possible extended bits, then we can turn this into
2324 // a zextload if we are running before legalize or the operation is legal.
2325 unsigned BitWidth = N1.getValueType().getScalarType().getSizeInBits();
2326 if (DAG.MaskedValueIsZero(N1, APInt::getHighBitsSet(BitWidth,
2327 BitWidth - MemVT.getScalarType().getSizeInBits())) &&
2328 ((!LegalOperations && !LN0->isVolatile()) ||
2329 TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT))) {
2330 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getDebugLoc(),
2332 LN0->getBasePtr(), LN0->getPointerInfo(),
2334 LN0->isVolatile(), LN0->isNonTemporal(),
2335 LN0->getAlignment());
2337 CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1));
2338 return SDValue(N, 0); // Return N so it doesn't get rechecked!
2342 // fold (and (load x), 255) -> (zextload x, i8)
2343 // fold (and (extload x, i16), 255) -> (zextload x, i8)
2344 // fold (and (any_ext (extload x, i16)), 255) -> (zextload x, i8)
2345 if (N1C && (N0.getOpcode() == ISD::LOAD ||
2346 (N0.getOpcode() == ISD::ANY_EXTEND &&
2347 N0.getOperand(0).getOpcode() == ISD::LOAD))) {
2348 bool HasAnyExt = N0.getOpcode() == ISD::ANY_EXTEND;
2349 LoadSDNode *LN0 = HasAnyExt
2350 ? cast<LoadSDNode>(N0.getOperand(0))
2351 : cast<LoadSDNode>(N0);
2352 if (LN0->getExtensionType() != ISD::SEXTLOAD &&
2353 LN0->isUnindexed() && N0.hasOneUse() && LN0->hasOneUse()) {
2354 uint32_t ActiveBits = N1C->getAPIntValue().getActiveBits();
2355 if (ActiveBits > 0 && APIntOps::isMask(ActiveBits, N1C->getAPIntValue())){
2356 EVT ExtVT = EVT::getIntegerVT(*DAG.getContext(), ActiveBits);
2357 EVT LoadedVT = LN0->getMemoryVT();
2359 if (ExtVT == LoadedVT &&
2360 (!LegalOperations || TLI.isLoadExtLegal(ISD::ZEXTLOAD, ExtVT))) {
2361 EVT LoadResultTy = HasAnyExt ? LN0->getValueType(0) : VT;
2364 DAG.getExtLoad(ISD::ZEXTLOAD, LoadResultTy, LN0->getDebugLoc(),
2365 LN0->getChain(), LN0->getBasePtr(),
2366 LN0->getPointerInfo(),
2367 ExtVT, LN0->isVolatile(), LN0->isNonTemporal(),
2368 LN0->getAlignment());
2370 CombineTo(LN0, NewLoad, NewLoad.getValue(1));
2371 return SDValue(N, 0); // Return N so it doesn't get rechecked!
2374 // Do not change the width of a volatile load.
2375 // Do not generate loads of non-round integer types since these can
2376 // be expensive (and would be wrong if the type is not byte sized).
2377 if (!LN0->isVolatile() && LoadedVT.bitsGT(ExtVT) && ExtVT.isRound() &&
2378 (!LegalOperations || TLI.isLoadExtLegal(ISD::ZEXTLOAD, ExtVT))) {
2379 EVT PtrType = LN0->getOperand(1).getValueType();
2381 unsigned Alignment = LN0->getAlignment();
2382 SDValue NewPtr = LN0->getBasePtr();
2384 // For big endian targets, we need to add an offset to the pointer
2385 // to load the correct bytes. For little endian systems, we merely
2386 // need to read fewer bytes from the same pointer.
2387 if (TLI.isBigEndian()) {
2388 unsigned LVTStoreBytes = LoadedVT.getStoreSize();
2389 unsigned EVTStoreBytes = ExtVT.getStoreSize();
2390 unsigned PtrOff = LVTStoreBytes - EVTStoreBytes;
2391 NewPtr = DAG.getNode(ISD::ADD, LN0->getDebugLoc(), PtrType,
2392 NewPtr, DAG.getConstant(PtrOff, PtrType));
2393 Alignment = MinAlign(Alignment, PtrOff);
2396 AddToWorkList(NewPtr.getNode());
2398 EVT LoadResultTy = HasAnyExt ? LN0->getValueType(0) : VT;
2400 DAG.getExtLoad(ISD::ZEXTLOAD, LoadResultTy, LN0->getDebugLoc(),
2401 LN0->getChain(), NewPtr,
2402 LN0->getPointerInfo(),
2403 ExtVT, LN0->isVolatile(), LN0->isNonTemporal(),
2406 CombineTo(LN0, Load, Load.getValue(1));
2407 return SDValue(N, 0); // Return N so it doesn't get rechecked!
2416 SDValue DAGCombiner::visitOR(SDNode *N) {
2417 SDValue N0 = N->getOperand(0);
2418 SDValue N1 = N->getOperand(1);
2419 SDValue LL, LR, RL, RR, CC0, CC1;
2420 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
2421 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
2422 EVT VT = N1.getValueType();
2425 if (VT.isVector()) {
2426 SDValue FoldedVOp = SimplifyVBinOp(N);
2427 if (FoldedVOp.getNode()) return FoldedVOp;
2430 // fold (or x, undef) -> -1
2431 if (!LegalOperations &&
2432 (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF)) {
2433 EVT EltVT = VT.isVector() ? VT.getVectorElementType() : VT;
2434 return DAG.getConstant(APInt::getAllOnesValue(EltVT.getSizeInBits()), VT);
2436 // fold (or c1, c2) -> c1|c2
2438 return DAG.FoldConstantArithmetic(ISD::OR, VT, N0C, N1C);
2439 // canonicalize constant to RHS
2441 return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N1, N0);
2442 // fold (or x, 0) -> x
2443 if (N1C && N1C->isNullValue())
2445 // fold (or x, -1) -> -1
2446 if (N1C && N1C->isAllOnesValue())
2448 // fold (or x, c) -> c iff (x & ~c) == 0
2449 if (N1C && DAG.MaskedValueIsZero(N0, ~N1C->getAPIntValue()))
2452 SDValue ROR = ReassociateOps(ISD::OR, N->getDebugLoc(), N0, N1);
2453 if (ROR.getNode() != 0)
2455 // Canonicalize (or (and X, c1), c2) -> (and (or X, c2), c1|c2)
2456 // iff (c1 & c2) == 0.
2457 if (N1C && N0.getOpcode() == ISD::AND && N0.getNode()->hasOneUse() &&
2458 isa<ConstantSDNode>(N0.getOperand(1))) {
2459 ConstantSDNode *C1 = cast<ConstantSDNode>(N0.getOperand(1));
2460 if ((C1->getAPIntValue() & N1C->getAPIntValue()) != 0)
2461 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT,
2462 DAG.getNode(ISD::OR, N0.getDebugLoc(), VT,
2463 N0.getOperand(0), N1),
2464 DAG.FoldConstantArithmetic(ISD::OR, VT, N1C, C1));
2466 // fold (or (setcc x), (setcc y)) -> (setcc (or x, y))
2467 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){
2468 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get();
2469 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get();
2471 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 &&
2472 LL.getValueType().isInteger()) {
2473 // fold (or (setne X, 0), (setne Y, 0)) -> (setne (or X, Y), 0)
2474 // fold (or (setlt X, 0), (setlt Y, 0)) -> (setne (or X, Y), 0)
2475 if (cast<ConstantSDNode>(LR)->isNullValue() &&
2476 (Op1 == ISD::SETNE || Op1 == ISD::SETLT)) {
2477 SDValue ORNode = DAG.getNode(ISD::OR, LR.getDebugLoc(),
2478 LR.getValueType(), LL, RL);
2479 AddToWorkList(ORNode.getNode());
2480 return DAG.getSetCC(N->getDebugLoc(), VT, ORNode, LR, Op1);
2482 // fold (or (setne X, -1), (setne Y, -1)) -> (setne (and X, Y), -1)
2483 // fold (or (setgt X, -1), (setgt Y -1)) -> (setgt (and X, Y), -1)
2484 if (cast<ConstantSDNode>(LR)->isAllOnesValue() &&
2485 (Op1 == ISD::SETNE || Op1 == ISD::SETGT)) {
2486 SDValue ANDNode = DAG.getNode(ISD::AND, LR.getDebugLoc(),
2487 LR.getValueType(), LL, RL);
2488 AddToWorkList(ANDNode.getNode());
2489 return DAG.getSetCC(N->getDebugLoc(), VT, ANDNode, LR, Op1);
2492 // canonicalize equivalent to ll == rl
2493 if (LL == RR && LR == RL) {
2494 Op1 = ISD::getSetCCSwappedOperands(Op1);
2497 if (LL == RL && LR == RR) {
2498 bool isInteger = LL.getValueType().isInteger();
2499 ISD::CondCode Result = ISD::getSetCCOrOperation(Op0, Op1, isInteger);
2500 if (Result != ISD::SETCC_INVALID &&
2501 (!LegalOperations || TLI.isCondCodeLegal(Result, LL.getValueType())))
2502 return DAG.getSetCC(N->getDebugLoc(), N0.getValueType(),
2507 // Simplify: (or (op x...), (op y...)) -> (op (or x, y))
2508 if (N0.getOpcode() == N1.getOpcode()) {
2509 SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N);
2510 if (Tmp.getNode()) return Tmp;
2513 // (or (and X, C1), (and Y, C2)) -> (and (or X, Y), C3) if possible.
2514 if (N0.getOpcode() == ISD::AND &&
2515 N1.getOpcode() == ISD::AND &&
2516 N0.getOperand(1).getOpcode() == ISD::Constant &&
2517 N1.getOperand(1).getOpcode() == ISD::Constant &&
2518 // Don't increase # computations.
2519 (N0.getNode()->hasOneUse() || N1.getNode()->hasOneUse())) {
2520 // We can only do this xform if we know that bits from X that are set in C2
2521 // but not in C1 are already zero. Likewise for Y.
2522 const APInt &LHSMask =
2523 cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue();
2524 const APInt &RHSMask =
2525 cast<ConstantSDNode>(N1.getOperand(1))->getAPIntValue();
2527 if (DAG.MaskedValueIsZero(N0.getOperand(0), RHSMask&~LHSMask) &&
2528 DAG.MaskedValueIsZero(N1.getOperand(0), LHSMask&~RHSMask)) {
2529 SDValue X = DAG.getNode(ISD::OR, N0.getDebugLoc(), VT,
2530 N0.getOperand(0), N1.getOperand(0));
2531 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, X,
2532 DAG.getConstant(LHSMask | RHSMask, VT));
2536 // See if this is some rotate idiom.
2537 if (SDNode *Rot = MatchRotate(N0, N1, N->getDebugLoc()))
2538 return SDValue(Rot, 0);
2540 // Simplify the operands using demanded-bits information.
2541 if (!VT.isVector() &&
2542 SimplifyDemandedBits(SDValue(N, 0)))
2543 return SDValue(N, 0);
2548 /// MatchRotateHalf - Match "(X shl/srl V1) & V2" where V2 may not be present.
2549 static bool MatchRotateHalf(SDValue Op, SDValue &Shift, SDValue &Mask) {
2550 if (Op.getOpcode() == ISD::AND) {
2551 if (isa<ConstantSDNode>(Op.getOperand(1))) {
2552 Mask = Op.getOperand(1);
2553 Op = Op.getOperand(0);
2559 if (Op.getOpcode() == ISD::SRL || Op.getOpcode() == ISD::SHL) {
2567 // MatchRotate - Handle an 'or' of two operands. If this is one of the many
2568 // idioms for rotate, and if the target supports rotation instructions, generate
2570 SDNode *DAGCombiner::MatchRotate(SDValue LHS, SDValue RHS, DebugLoc DL) {
2571 // Must be a legal type. Expanded 'n promoted things won't work with rotates.
2572 EVT VT = LHS.getValueType();
2573 if (!TLI.isTypeLegal(VT)) return 0;
2575 // The target must have at least one rotate flavor.
2576 bool HasROTL = TLI.isOperationLegalOrCustom(ISD::ROTL, VT);
2577 bool HasROTR = TLI.isOperationLegalOrCustom(ISD::ROTR, VT);
2578 if (!HasROTL && !HasROTR) return 0;
2580 // Match "(X shl/srl V1) & V2" where V2 may not be present.
2581 SDValue LHSShift; // The shift.
2582 SDValue LHSMask; // AND value if any.
2583 if (!MatchRotateHalf(LHS, LHSShift, LHSMask))
2584 return 0; // Not part of a rotate.
2586 SDValue RHSShift; // The shift.
2587 SDValue RHSMask; // AND value if any.
2588 if (!MatchRotateHalf(RHS, RHSShift, RHSMask))
2589 return 0; // Not part of a rotate.
2591 if (LHSShift.getOperand(0) != RHSShift.getOperand(0))
2592 return 0; // Not shifting the same value.
2594 if (LHSShift.getOpcode() == RHSShift.getOpcode())
2595 return 0; // Shifts must disagree.
2597 // Canonicalize shl to left side in a shl/srl pair.
2598 if (RHSShift.getOpcode() == ISD::SHL) {
2599 std::swap(LHS, RHS);
2600 std::swap(LHSShift, RHSShift);
2601 std::swap(LHSMask , RHSMask );
2604 unsigned OpSizeInBits = VT.getSizeInBits();
2605 SDValue LHSShiftArg = LHSShift.getOperand(0);
2606 SDValue LHSShiftAmt = LHSShift.getOperand(1);
2607 SDValue RHSShiftAmt = RHSShift.getOperand(1);
2609 // fold (or (shl x, C1), (srl x, C2)) -> (rotl x, C1)
2610 // fold (or (shl x, C1), (srl x, C2)) -> (rotr x, C2)
2611 if (LHSShiftAmt.getOpcode() == ISD::Constant &&
2612 RHSShiftAmt.getOpcode() == ISD::Constant) {
2613 uint64_t LShVal = cast<ConstantSDNode>(LHSShiftAmt)->getZExtValue();
2614 uint64_t RShVal = cast<ConstantSDNode>(RHSShiftAmt)->getZExtValue();
2615 if ((LShVal + RShVal) != OpSizeInBits)
2620 Rot = DAG.getNode(ISD::ROTL, DL, VT, LHSShiftArg, LHSShiftAmt);
2622 Rot = DAG.getNode(ISD::ROTR, DL, VT, LHSShiftArg, RHSShiftAmt);
2624 // If there is an AND of either shifted operand, apply it to the result.
2625 if (LHSMask.getNode() || RHSMask.getNode()) {
2626 APInt Mask = APInt::getAllOnesValue(OpSizeInBits);
2628 if (LHSMask.getNode()) {
2629 APInt RHSBits = APInt::getLowBitsSet(OpSizeInBits, LShVal);
2630 Mask &= cast<ConstantSDNode>(LHSMask)->getAPIntValue() | RHSBits;
2632 if (RHSMask.getNode()) {
2633 APInt LHSBits = APInt::getHighBitsSet(OpSizeInBits, RShVal);
2634 Mask &= cast<ConstantSDNode>(RHSMask)->getAPIntValue() | LHSBits;
2637 Rot = DAG.getNode(ISD::AND, DL, VT, Rot, DAG.getConstant(Mask, VT));
2640 return Rot.getNode();
2643 // If there is a mask here, and we have a variable shift, we can't be sure
2644 // that we're masking out the right stuff.
2645 if (LHSMask.getNode() || RHSMask.getNode())
2648 // fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotl x, y)
2649 // fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotr x, (sub 32, y))
2650 if (RHSShiftAmt.getOpcode() == ISD::SUB &&
2651 LHSShiftAmt == RHSShiftAmt.getOperand(1)) {
2652 if (ConstantSDNode *SUBC =
2653 dyn_cast<ConstantSDNode>(RHSShiftAmt.getOperand(0))) {
2654 if (SUBC->getAPIntValue() == OpSizeInBits) {
2656 return DAG.getNode(ISD::ROTL, DL, VT,
2657 LHSShiftArg, LHSShiftAmt).getNode();
2659 return DAG.getNode(ISD::ROTR, DL, VT,
2660 LHSShiftArg, RHSShiftAmt).getNode();
2665 // fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotr x, y)
2666 // fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotl x, (sub 32, y))
2667 if (LHSShiftAmt.getOpcode() == ISD::SUB &&
2668 RHSShiftAmt == LHSShiftAmt.getOperand(1)) {
2669 if (ConstantSDNode *SUBC =
2670 dyn_cast<ConstantSDNode>(LHSShiftAmt.getOperand(0))) {
2671 if (SUBC->getAPIntValue() == OpSizeInBits) {
2673 return DAG.getNode(ISD::ROTR, DL, VT,
2674 LHSShiftArg, RHSShiftAmt).getNode();
2676 return DAG.getNode(ISD::ROTL, DL, VT,
2677 LHSShiftArg, LHSShiftAmt).getNode();
2682 // Look for sign/zext/any-extended or truncate cases:
2683 if ((LHSShiftAmt.getOpcode() == ISD::SIGN_EXTEND
2684 || LHSShiftAmt.getOpcode() == ISD::ZERO_EXTEND
2685 || LHSShiftAmt.getOpcode() == ISD::ANY_EXTEND
2686 || LHSShiftAmt.getOpcode() == ISD::TRUNCATE) &&
2687 (RHSShiftAmt.getOpcode() == ISD::SIGN_EXTEND
2688 || RHSShiftAmt.getOpcode() == ISD::ZERO_EXTEND
2689 || RHSShiftAmt.getOpcode() == ISD::ANY_EXTEND
2690 || RHSShiftAmt.getOpcode() == ISD::TRUNCATE)) {
2691 SDValue LExtOp0 = LHSShiftAmt.getOperand(0);
2692 SDValue RExtOp0 = RHSShiftAmt.getOperand(0);
2693 if (RExtOp0.getOpcode() == ISD::SUB &&
2694 RExtOp0.getOperand(1) == LExtOp0) {
2695 // fold (or (shl x, (*ext y)), (srl x, (*ext (sub 32, y)))) ->
2697 // fold (or (shl x, (*ext y)), (srl x, (*ext (sub 32, y)))) ->
2698 // (rotr x, (sub 32, y))
2699 if (ConstantSDNode *SUBC =
2700 dyn_cast<ConstantSDNode>(RExtOp0.getOperand(0))) {
2701 if (SUBC->getAPIntValue() == OpSizeInBits) {
2702 return DAG.getNode(HasROTL ? ISD::ROTL : ISD::ROTR, DL, VT,
2704 HasROTL ? LHSShiftAmt : RHSShiftAmt).getNode();
2707 } else if (LExtOp0.getOpcode() == ISD::SUB &&
2708 RExtOp0 == LExtOp0.getOperand(1)) {
2709 // fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext y))) ->
2711 // fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext y))) ->
2712 // (rotl x, (sub 32, y))
2713 if (ConstantSDNode *SUBC =
2714 dyn_cast<ConstantSDNode>(LExtOp0.getOperand(0))) {
2715 if (SUBC->getAPIntValue() == OpSizeInBits) {
2716 return DAG.getNode(HasROTR ? ISD::ROTR : ISD::ROTL, DL, VT,
2718 HasROTR ? RHSShiftAmt : LHSShiftAmt).getNode();
2727 SDValue DAGCombiner::visitXOR(SDNode *N) {
2728 SDValue N0 = N->getOperand(0);
2729 SDValue N1 = N->getOperand(1);
2730 SDValue LHS, RHS, CC;
2731 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
2732 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
2733 EVT VT = N0.getValueType();
2736 if (VT.isVector()) {
2737 SDValue FoldedVOp = SimplifyVBinOp(N);
2738 if (FoldedVOp.getNode()) return FoldedVOp;
2741 // fold (xor undef, undef) -> 0. This is a common idiom (misuse).
2742 if (N0.getOpcode() == ISD::UNDEF && N1.getOpcode() == ISD::UNDEF)
2743 return DAG.getConstant(0, VT);
2744 // fold (xor x, undef) -> undef
2745 if (N0.getOpcode() == ISD::UNDEF)
2747 if (N1.getOpcode() == ISD::UNDEF)
2749 // fold (xor c1, c2) -> c1^c2
2751 return DAG.FoldConstantArithmetic(ISD::XOR, VT, N0C, N1C);
2752 // canonicalize constant to RHS
2754 return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N1, N0);
2755 // fold (xor x, 0) -> x
2756 if (N1C && N1C->isNullValue())
2759 SDValue RXOR = ReassociateOps(ISD::XOR, N->getDebugLoc(), N0, N1);
2760 if (RXOR.getNode() != 0)
2763 // fold !(x cc y) -> (x !cc y)
2764 if (N1C && N1C->getAPIntValue() == 1 && isSetCCEquivalent(N0, LHS, RHS, CC)) {
2765 bool isInt = LHS.getValueType().isInteger();
2766 ISD::CondCode NotCC = ISD::getSetCCInverse(cast<CondCodeSDNode>(CC)->get(),
2769 if (!LegalOperations || TLI.isCondCodeLegal(NotCC, LHS.getValueType())) {
2770 switch (N0.getOpcode()) {
2772 llvm_unreachable("Unhandled SetCC Equivalent!");
2774 return DAG.getSetCC(N->getDebugLoc(), VT, LHS, RHS, NotCC);
2775 case ISD::SELECT_CC:
2776 return DAG.getSelectCC(N->getDebugLoc(), LHS, RHS, N0.getOperand(2),
2777 N0.getOperand(3), NotCC);
2782 // fold (not (zext (setcc x, y))) -> (zext (not (setcc x, y)))
2783 if (N1C && N1C->getAPIntValue() == 1 && N0.getOpcode() == ISD::ZERO_EXTEND &&
2784 N0.getNode()->hasOneUse() &&
2785 isSetCCEquivalent(N0.getOperand(0), LHS, RHS, CC)){
2786 SDValue V = N0.getOperand(0);
2787 V = DAG.getNode(ISD::XOR, N0.getDebugLoc(), V.getValueType(), V,
2788 DAG.getConstant(1, V.getValueType()));
2789 AddToWorkList(V.getNode());
2790 return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, V);
2793 // fold (not (or x, y)) -> (and (not x), (not y)) iff x or y are setcc
2794 if (N1C && N1C->getAPIntValue() == 1 && VT == MVT::i1 &&
2795 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) {
2796 SDValue LHS = N0.getOperand(0), RHS = N0.getOperand(1);
2797 if (isOneUseSetCC(RHS) || isOneUseSetCC(LHS)) {
2798 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND;
2799 LHS = DAG.getNode(ISD::XOR, LHS.getDebugLoc(), VT, LHS, N1); // LHS = ~LHS
2800 RHS = DAG.getNode(ISD::XOR, RHS.getDebugLoc(), VT, RHS, N1); // RHS = ~RHS
2801 AddToWorkList(LHS.getNode()); AddToWorkList(RHS.getNode());
2802 return DAG.getNode(NewOpcode, N->getDebugLoc(), VT, LHS, RHS);
2805 // fold (not (or x, y)) -> (and (not x), (not y)) iff x or y are constants
2806 if (N1C && N1C->isAllOnesValue() &&
2807 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) {
2808 SDValue LHS = N0.getOperand(0), RHS = N0.getOperand(1);
2809 if (isa<ConstantSDNode>(RHS) || isa<ConstantSDNode>(LHS)) {
2810 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND;
2811 LHS = DAG.getNode(ISD::XOR, LHS.getDebugLoc(), VT, LHS, N1); // LHS = ~LHS
2812 RHS = DAG.getNode(ISD::XOR, RHS.getDebugLoc(), VT, RHS, N1); // RHS = ~RHS
2813 AddToWorkList(LHS.getNode()); AddToWorkList(RHS.getNode());
2814 return DAG.getNode(NewOpcode, N->getDebugLoc(), VT, LHS, RHS);
2817 // fold (xor (xor x, c1), c2) -> (xor x, (xor c1, c2))
2818 if (N1C && N0.getOpcode() == ISD::XOR) {
2819 ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0));
2820 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
2822 return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N0.getOperand(1),
2823 DAG.getConstant(N1C->getAPIntValue() ^
2824 N00C->getAPIntValue(), VT));
2826 return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N0.getOperand(0),
2827 DAG.getConstant(N1C->getAPIntValue() ^
2828 N01C->getAPIntValue(), VT));
2830 // fold (xor x, x) -> 0
2832 if (!VT.isVector()) {
2833 return DAG.getConstant(0, VT);
2834 } else if (!LegalOperations || TLI.isOperationLegal(ISD::BUILD_VECTOR, VT)){
2835 // Produce a vector of zeros.
2836 SDValue El = DAG.getConstant(0, VT.getVectorElementType());
2837 std::vector<SDValue> Ops(VT.getVectorNumElements(), El);
2838 return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), VT,
2839 &Ops[0], Ops.size());
2843 // Simplify: xor (op x...), (op y...) -> (op (xor x, y))
2844 if (N0.getOpcode() == N1.getOpcode()) {
2845 SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N);
2846 if (Tmp.getNode()) return Tmp;
2849 // Simplify the expression using non-local knowledge.
2850 if (!VT.isVector() &&
2851 SimplifyDemandedBits(SDValue(N, 0)))
2852 return SDValue(N, 0);
2857 /// visitShiftByConstant - Handle transforms common to the three shifts, when
2858 /// the shift amount is a constant.
2859 SDValue DAGCombiner::visitShiftByConstant(SDNode *N, unsigned Amt) {
2860 SDNode *LHS = N->getOperand(0).getNode();
2861 if (!LHS->hasOneUse()) return SDValue();
2863 // We want to pull some binops through shifts, so that we have (and (shift))
2864 // instead of (shift (and)), likewise for add, or, xor, etc. This sort of
2865 // thing happens with address calculations, so it's important to canonicalize
2867 bool HighBitSet = false; // Can we transform this if the high bit is set?
2869 switch (LHS->getOpcode()) {
2870 default: return SDValue();
2873 HighBitSet = false; // We can only transform sra if the high bit is clear.
2876 HighBitSet = true; // We can only transform sra if the high bit is set.
2879 if (N->getOpcode() != ISD::SHL)
2880 return SDValue(); // only shl(add) not sr[al](add).
2881 HighBitSet = false; // We can only transform sra if the high bit is clear.
2885 // We require the RHS of the binop to be a constant as well.
2886 ConstantSDNode *BinOpCst = dyn_cast<ConstantSDNode>(LHS->getOperand(1));
2887 if (!BinOpCst) return SDValue();
2889 // FIXME: disable this unless the input to the binop is a shift by a constant.
2890 // If it is not a shift, it pessimizes some common cases like:
2892 // void foo(int *X, int i) { X[i & 1235] = 1; }
2893 // int bar(int *X, int i) { return X[i & 255]; }
2894 SDNode *BinOpLHSVal = LHS->getOperand(0).getNode();
2895 if ((BinOpLHSVal->getOpcode() != ISD::SHL &&
2896 BinOpLHSVal->getOpcode() != ISD::SRA &&
2897 BinOpLHSVal->getOpcode() != ISD::SRL) ||
2898 !isa<ConstantSDNode>(BinOpLHSVal->getOperand(1)))
2901 EVT VT = N->getValueType(0);
2903 // If this is a signed shift right, and the high bit is modified by the
2904 // logical operation, do not perform the transformation. The highBitSet
2905 // boolean indicates the value of the high bit of the constant which would
2906 // cause it to be modified for this operation.
2907 if (N->getOpcode() == ISD::SRA) {
2908 bool BinOpRHSSignSet = BinOpCst->getAPIntValue().isNegative();
2909 if (BinOpRHSSignSet != HighBitSet)
2913 // Fold the constants, shifting the binop RHS by the shift amount.
2914 SDValue NewRHS = DAG.getNode(N->getOpcode(), LHS->getOperand(1).getDebugLoc(),
2916 LHS->getOperand(1), N->getOperand(1));
2918 // Create the new shift.
2919 SDValue NewShift = DAG.getNode(N->getOpcode(),
2920 LHS->getOperand(0).getDebugLoc(),
2921 VT, LHS->getOperand(0), N->getOperand(1));
2923 // Create the new binop.
2924 return DAG.getNode(LHS->getOpcode(), N->getDebugLoc(), VT, NewShift, NewRHS);
2927 SDValue DAGCombiner::visitSHL(SDNode *N) {
2928 SDValue N0 = N->getOperand(0);
2929 SDValue N1 = N->getOperand(1);
2930 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
2931 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
2932 EVT VT = N0.getValueType();
2933 unsigned OpSizeInBits = VT.getScalarType().getSizeInBits();
2935 // fold (shl c1, c2) -> c1<<c2
2937 return DAG.FoldConstantArithmetic(ISD::SHL, VT, N0C, N1C);
2938 // fold (shl 0, x) -> 0
2939 if (N0C && N0C->isNullValue())
2941 // fold (shl x, c >= size(x)) -> undef
2942 if (N1C && N1C->getZExtValue() >= OpSizeInBits)
2943 return DAG.getUNDEF(VT);
2944 // fold (shl x, 0) -> x
2945 if (N1C && N1C->isNullValue())
2947 // if (shl x, c) is known to be zero, return 0
2948 if (DAG.MaskedValueIsZero(SDValue(N, 0),
2949 APInt::getAllOnesValue(OpSizeInBits)))
2950 return DAG.getConstant(0, VT);
2951 // fold (shl x, (trunc (and y, c))) -> (shl x, (and (trunc y), (trunc c))).
2952 if (N1.getOpcode() == ISD::TRUNCATE &&
2953 N1.getOperand(0).getOpcode() == ISD::AND &&
2954 N1.hasOneUse() && N1.getOperand(0).hasOneUse()) {
2955 SDValue N101 = N1.getOperand(0).getOperand(1);
2956 if (ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N101)) {
2957 EVT TruncVT = N1.getValueType();
2958 SDValue N100 = N1.getOperand(0).getOperand(0);
2959 APInt TruncC = N101C->getAPIntValue();
2960 TruncC = TruncC.trunc(TruncVT.getSizeInBits());
2961 return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0,
2962 DAG.getNode(ISD::AND, N->getDebugLoc(), TruncVT,
2963 DAG.getNode(ISD::TRUNCATE,
2966 DAG.getConstant(TruncC, TruncVT)));
2970 if (N1C && SimplifyDemandedBits(SDValue(N, 0)))
2971 return SDValue(N, 0);
2973 // fold (shl (shl x, c1), c2) -> 0 or (shl x, (add c1, c2))
2974 if (N1C && N0.getOpcode() == ISD::SHL &&
2975 N0.getOperand(1).getOpcode() == ISD::Constant) {
2976 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue();
2977 uint64_t c2 = N1C->getZExtValue();
2978 if (c1 + c2 >= OpSizeInBits)
2979 return DAG.getConstant(0, VT);
2980 return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0.getOperand(0),
2981 DAG.getConstant(c1 + c2, N1.getValueType()));
2984 // fold (shl (ext (shl x, c1)), c2) -> (ext (shl x, (add c1, c2)))
2985 // For this to be valid, the second form must not preserve any of the bits
2986 // that are shifted out by the inner shift in the first form. This means
2987 // the outer shift size must be >= the number of bits added by the ext.
2988 // As a corollary, we don't care what kind of ext it is.
2989 if (N1C && (N0.getOpcode() == ISD::ZERO_EXTEND ||
2990 N0.getOpcode() == ISD::ANY_EXTEND ||
2991 N0.getOpcode() == ISD::SIGN_EXTEND) &&
2992 N0.getOperand(0).getOpcode() == ISD::SHL &&
2993 isa<ConstantSDNode>(N0.getOperand(0)->getOperand(1))) {
2995 cast<ConstantSDNode>(N0.getOperand(0)->getOperand(1))->getZExtValue();
2996 uint64_t c2 = N1C->getZExtValue();
2997 EVT InnerShiftVT = N0.getOperand(0).getValueType();
2998 uint64_t InnerShiftSize = InnerShiftVT.getScalarType().getSizeInBits();
2999 if (c2 >= OpSizeInBits - InnerShiftSize) {
3000 if (c1 + c2 >= OpSizeInBits)
3001 return DAG.getConstant(0, VT);
3002 return DAG.getNode(ISD::SHL, N0->getDebugLoc(), VT,
3003 DAG.getNode(N0.getOpcode(), N0->getDebugLoc(), VT,
3004 N0.getOperand(0)->getOperand(0)),
3005 DAG.getConstant(c1 + c2, N1.getValueType()));
3009 // fold (shl (srl x, c1), c2) -> (shl (and x, (shl -1, c1)), (sub c2, c1)) or
3010 // (srl (and x, (shl -1, c1)), (sub c1, c2))
3011 if (N1C && N0.getOpcode() == ISD::SRL &&
3012 N0.getOperand(1).getOpcode() == ISD::Constant) {
3013 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue();
3014 if (c1 < VT.getSizeInBits()) {
3015 uint64_t c2 = N1C->getZExtValue();
3016 SDValue HiBitsMask =
3017 DAG.getConstant(APInt::getHighBitsSet(VT.getSizeInBits(),
3018 VT.getSizeInBits() - c1),
3020 SDValue Mask = DAG.getNode(ISD::AND, N0.getDebugLoc(), VT,
3024 return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, Mask,
3025 DAG.getConstant(c2-c1, N1.getValueType()));
3027 return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, Mask,
3028 DAG.getConstant(c1-c2, N1.getValueType()));
3031 // fold (shl (sra x, c1), c1) -> (and x, (shl -1, c1))
3032 if (N1C && N0.getOpcode() == ISD::SRA && N1 == N0.getOperand(1)) {
3033 SDValue HiBitsMask =
3034 DAG.getConstant(APInt::getHighBitsSet(VT.getSizeInBits(),
3035 VT.getSizeInBits() -
3036 N1C->getZExtValue()),
3038 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0.getOperand(0),
3043 SDValue NewSHL = visitShiftByConstant(N, N1C->getZExtValue());
3044 if (NewSHL.getNode())
3051 SDValue DAGCombiner::visitSRA(SDNode *N) {
3052 SDValue N0 = N->getOperand(0);
3053 SDValue N1 = N->getOperand(1);
3054 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
3055 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
3056 EVT VT = N0.getValueType();
3057 unsigned OpSizeInBits = VT.getScalarType().getSizeInBits();
3059 // fold (sra c1, c2) -> (sra c1, c2)
3061 return DAG.FoldConstantArithmetic(ISD::SRA, VT, N0C, N1C);
3062 // fold (sra 0, x) -> 0
3063 if (N0C && N0C->isNullValue())
3065 // fold (sra -1, x) -> -1
3066 if (N0C && N0C->isAllOnesValue())
3068 // fold (sra x, (setge c, size(x))) -> undef
3069 if (N1C && N1C->getZExtValue() >= OpSizeInBits)
3070 return DAG.getUNDEF(VT);
3071 // fold (sra x, 0) -> x
3072 if (N1C && N1C->isNullValue())
3074 // fold (sra (shl x, c1), c1) -> sext_inreg for some c1 and target supports
3076 if (N1C && N0.getOpcode() == ISD::SHL && N1 == N0.getOperand(1)) {
3077 unsigned LowBits = OpSizeInBits - (unsigned)N1C->getZExtValue();
3078 EVT ExtVT = EVT::getIntegerVT(*DAG.getContext(), LowBits);
3080 ExtVT = EVT::getVectorVT(*DAG.getContext(),
3081 ExtVT, VT.getVectorNumElements());
3082 if ((!LegalOperations ||
3083 TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, ExtVT)))
3084 return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT,
3085 N0.getOperand(0), DAG.getValueType(ExtVT));
3088 // fold (sra (sra x, c1), c2) -> (sra x, (add c1, c2))
3089 if (N1C && N0.getOpcode() == ISD::SRA) {
3090 if (ConstantSDNode *C1 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
3091 unsigned Sum = N1C->getZExtValue() + C1->getZExtValue();
3092 if (Sum >= OpSizeInBits) Sum = OpSizeInBits-1;
3093 return DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, N0.getOperand(0),
3094 DAG.getConstant(Sum, N1C->getValueType(0)));
3098 // fold (sra (shl X, m), (sub result_size, n))
3099 // -> (sign_extend (trunc (shl X, (sub (sub result_size, n), m)))) for
3100 // result_size - n != m.
3101 // If truncate is free for the target sext(shl) is likely to result in better
3103 if (N0.getOpcode() == ISD::SHL) {
3104 // Get the two constanst of the shifts, CN0 = m, CN = n.
3105 const ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
3107 // Determine what the truncate's result bitsize and type would be.
3109 EVT::getIntegerVT(*DAG.getContext(),
3110 OpSizeInBits - N1C->getZExtValue());
3111 // Determine the residual right-shift amount.
3112 signed ShiftAmt = N1C->getZExtValue() - N01C->getZExtValue();
3114 // If the shift is not a no-op (in which case this should be just a sign
3115 // extend already), the truncated to type is legal, sign_extend is legal
3116 // on that type, and the truncate to that type is both legal and free,
3117 // perform the transform.
3118 if ((ShiftAmt > 0) &&
3119 TLI.isOperationLegalOrCustom(ISD::SIGN_EXTEND, TruncVT) &&
3120 TLI.isOperationLegalOrCustom(ISD::TRUNCATE, VT) &&
3121 TLI.isTruncateFree(VT, TruncVT)) {
3123 SDValue Amt = DAG.getConstant(ShiftAmt, getShiftAmountTy());
3124 SDValue Shift = DAG.getNode(ISD::SRL, N0.getDebugLoc(), VT,
3125 N0.getOperand(0), Amt);
3126 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), TruncVT,
3128 return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(),
3129 N->getValueType(0), Trunc);
3134 // fold (sra x, (trunc (and y, c))) -> (sra x, (and (trunc y), (trunc c))).
3135 if (N1.getOpcode() == ISD::TRUNCATE &&
3136 N1.getOperand(0).getOpcode() == ISD::AND &&
3137 N1.hasOneUse() && N1.getOperand(0).hasOneUse()) {
3138 SDValue N101 = N1.getOperand(0).getOperand(1);
3139 if (ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N101)) {
3140 EVT TruncVT = N1.getValueType();
3141 SDValue N100 = N1.getOperand(0).getOperand(0);
3142 APInt TruncC = N101C->getAPIntValue();
3143 TruncC = TruncC.trunc(TruncVT.getScalarType().getSizeInBits());
3144 return DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, N0,
3145 DAG.getNode(ISD::AND, N->getDebugLoc(),
3147 DAG.getNode(ISD::TRUNCATE,
3150 DAG.getConstant(TruncC, TruncVT)));
3154 // Simplify, based on bits shifted out of the LHS.
3155 if (N1C && SimplifyDemandedBits(SDValue(N, 0)))
3156 return SDValue(N, 0);
3159 // If the sign bit is known to be zero, switch this to a SRL.
3160 if (DAG.SignBitIsZero(N0))
3161 return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0, N1);
3164 SDValue NewSRA = visitShiftByConstant(N, N1C->getZExtValue());
3165 if (NewSRA.getNode())
3172 SDValue DAGCombiner::visitSRL(SDNode *N) {
3173 SDValue N0 = N->getOperand(0);
3174 SDValue N1 = N->getOperand(1);
3175 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
3176 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
3177 EVT VT = N0.getValueType();
3178 unsigned OpSizeInBits = VT.getScalarType().getSizeInBits();
3180 // fold (srl c1, c2) -> c1 >>u c2
3182 return DAG.FoldConstantArithmetic(ISD::SRL, VT, N0C, N1C);
3183 // fold (srl 0, x) -> 0
3184 if (N0C && N0C->isNullValue())
3186 // fold (srl x, c >= size(x)) -> undef
3187 if (N1C && N1C->getZExtValue() >= OpSizeInBits)
3188 return DAG.getUNDEF(VT);
3189 // fold (srl x, 0) -> x
3190 if (N1C && N1C->isNullValue())
3192 // if (srl x, c) is known to be zero, return 0
3193 if (N1C && DAG.MaskedValueIsZero(SDValue(N, 0),
3194 APInt::getAllOnesValue(OpSizeInBits)))
3195 return DAG.getConstant(0, VT);
3197 // fold (srl (srl x, c1), c2) -> 0 or (srl x, (add c1, c2))
3198 if (N1C && N0.getOpcode() == ISD::SRL &&
3199 N0.getOperand(1).getOpcode() == ISD::Constant) {
3200 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue();
3201 uint64_t c2 = N1C->getZExtValue();
3202 if (c1 + c2 >= OpSizeInBits)
3203 return DAG.getConstant(0, VT);
3204 return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0.getOperand(0),
3205 DAG.getConstant(c1 + c2, N1.getValueType()));
3208 // fold (srl (trunc (srl x, c1)), c2) -> 0 or (trunc (srl x, (add c1, c2)))
3209 if (N1C && N0.getOpcode() == ISD::TRUNCATE &&
3210 N0.getOperand(0).getOpcode() == ISD::SRL &&
3211 isa<ConstantSDNode>(N0.getOperand(0)->getOperand(1))) {
3213 cast<ConstantSDNode>(N0.getOperand(0)->getOperand(1))->getZExtValue();
3214 uint64_t c2 = N1C->getZExtValue();
3215 EVT InnerShiftVT = N0.getOperand(0).getValueType();
3216 EVT ShiftCountVT = N0.getOperand(0)->getOperand(1).getValueType();
3217 uint64_t InnerShiftSize = InnerShiftVT.getScalarType().getSizeInBits();
3218 // This is only valid if the OpSizeInBits + c1 = size of inner shift.
3219 if (c1 + OpSizeInBits == InnerShiftSize) {
3220 if (c1 + c2 >= InnerShiftSize)
3221 return DAG.getConstant(0, VT);
3222 return DAG.getNode(ISD::TRUNCATE, N0->getDebugLoc(), VT,
3223 DAG.getNode(ISD::SRL, N0->getDebugLoc(), InnerShiftVT,
3224 N0.getOperand(0)->getOperand(0),
3225 DAG.getConstant(c1 + c2, ShiftCountVT)));
3229 // fold (srl (shl x, c), c) -> (and x, cst2)
3230 if (N1C && N0.getOpcode() == ISD::SHL && N0.getOperand(1) == N1 &&
3231 N0.getValueSizeInBits() <= 64) {
3232 uint64_t ShAmt = N1C->getZExtValue()+64-N0.getValueSizeInBits();
3233 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0.getOperand(0),
3234 DAG.getConstant(~0ULL >> ShAmt, VT));
3238 // fold (srl (anyextend x), c) -> (anyextend (srl x, c))
3239 if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) {
3240 // Shifting in all undef bits?
3241 EVT SmallVT = N0.getOperand(0).getValueType();
3242 if (N1C->getZExtValue() >= SmallVT.getSizeInBits())
3243 return DAG.getUNDEF(VT);
3245 if (!LegalTypes || TLI.isTypeDesirableForOp(ISD::SRL, SmallVT)) {
3246 SDValue SmallShift = DAG.getNode(ISD::SRL, N0.getDebugLoc(), SmallVT,
3247 N0.getOperand(0), N1);
3248 AddToWorkList(SmallShift.getNode());
3249 return DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, SmallShift);
3253 // fold (srl (sra X, Y), 31) -> (srl X, 31). This srl only looks at the sign
3254 // bit, which is unmodified by sra.
3255 if (N1C && N1C->getZExtValue() + 1 == VT.getSizeInBits()) {
3256 if (N0.getOpcode() == ISD::SRA)
3257 return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0.getOperand(0), N1);
3260 // fold (srl (ctlz x), "5") -> x iff x has one bit set (the low bit).
3261 if (N1C && N0.getOpcode() == ISD::CTLZ &&
3262 N1C->getAPIntValue() == Log2_32(VT.getSizeInBits())) {
3263 APInt KnownZero, KnownOne;
3264 APInt Mask = APInt::getAllOnesValue(VT.getScalarType().getSizeInBits());
3265 DAG.ComputeMaskedBits(N0.getOperand(0), Mask, KnownZero, KnownOne);
3267 // If any of the input bits are KnownOne, then the input couldn't be all
3268 // zeros, thus the result of the srl will always be zero.
3269 if (KnownOne.getBoolValue()) return DAG.getConstant(0, VT);
3271 // If all of the bits input the to ctlz node are known to be zero, then
3272 // the result of the ctlz is "32" and the result of the shift is one.
3273 APInt UnknownBits = ~KnownZero & Mask;
3274 if (UnknownBits == 0) return DAG.getConstant(1, VT);
3276 // Otherwise, check to see if there is exactly one bit input to the ctlz.
3277 if ((UnknownBits & (UnknownBits - 1)) == 0) {
3278 // Okay, we know that only that the single bit specified by UnknownBits
3279 // could be set on input to the CTLZ node. If this bit is set, the SRL
3280 // will return 0, if it is clear, it returns 1. Change the CTLZ/SRL pair
3281 // to an SRL/XOR pair, which is likely to simplify more.
3282 unsigned ShAmt = UnknownBits.countTrailingZeros();
3283 SDValue Op = N0.getOperand(0);
3286 Op = DAG.getNode(ISD::SRL, N0.getDebugLoc(), VT, Op,
3287 DAG.getConstant(ShAmt, getShiftAmountTy()));
3288 AddToWorkList(Op.getNode());
3291 return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT,
3292 Op, DAG.getConstant(1, VT));
3296 // fold (srl x, (trunc (and y, c))) -> (srl x, (and (trunc y), (trunc c))).
3297 if (N1.getOpcode() == ISD::TRUNCATE &&
3298 N1.getOperand(0).getOpcode() == ISD::AND &&
3299 N1.hasOneUse() && N1.getOperand(0).hasOneUse()) {
3300 SDValue N101 = N1.getOperand(0).getOperand(1);
3301 if (ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N101)) {
3302 EVT TruncVT = N1.getValueType();
3303 SDValue N100 = N1.getOperand(0).getOperand(0);
3304 APInt TruncC = N101C->getAPIntValue();
3305 TruncC = TruncC.trunc(TruncVT.getSizeInBits());
3306 return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0,
3307 DAG.getNode(ISD::AND, N->getDebugLoc(),
3309 DAG.getNode(ISD::TRUNCATE,
3312 DAG.getConstant(TruncC, TruncVT)));
3316 // fold operands of srl based on knowledge that the low bits are not
3318 if (N1C && SimplifyDemandedBits(SDValue(N, 0)))
3319 return SDValue(N, 0);
3322 SDValue NewSRL = visitShiftByConstant(N, N1C->getZExtValue());
3323 if (NewSRL.getNode())
3327 // Attempt to convert a srl of a load into a narrower zero-extending load.
3328 SDValue NarrowLoad = ReduceLoadWidth(N);
3329 if (NarrowLoad.getNode())
3332 // Here is a common situation. We want to optimize:
3335 // %b = and i32 %a, 2
3336 // %c = srl i32 %b, 1
3337 // brcond i32 %c ...
3343 // %c = setcc eq %b, 0
3346 // However when after the source operand of SRL is optimized into AND, the SRL
3347 // itself may not be optimized further. Look for it and add the BRCOND into
3349 if (N->hasOneUse()) {
3350 SDNode *Use = *N->use_begin();
3351 if (Use->getOpcode() == ISD::BRCOND)
3353 else if (Use->getOpcode() == ISD::TRUNCATE && Use->hasOneUse()) {
3354 // Also look pass the truncate.
3355 Use = *Use->use_begin();
3356 if (Use->getOpcode() == ISD::BRCOND)
3364 SDValue DAGCombiner::visitCTLZ(SDNode *N) {
3365 SDValue N0 = N->getOperand(0);
3366 EVT VT = N->getValueType(0);
3368 // fold (ctlz c1) -> c2
3369 if (isa<ConstantSDNode>(N0))
3370 return DAG.getNode(ISD::CTLZ, N->getDebugLoc(), VT, N0);
3374 SDValue DAGCombiner::visitCTTZ(SDNode *N) {
3375 SDValue N0 = N->getOperand(0);
3376 EVT VT = N->getValueType(0);
3378 // fold (cttz c1) -> c2
3379 if (isa<ConstantSDNode>(N0))
3380 return DAG.getNode(ISD::CTTZ, N->getDebugLoc(), VT, N0);
3384 SDValue DAGCombiner::visitCTPOP(SDNode *N) {
3385 SDValue N0 = N->getOperand(0);
3386 EVT VT = N->getValueType(0);
3388 // fold (ctpop c1) -> c2
3389 if (isa<ConstantSDNode>(N0))
3390 return DAG.getNode(ISD::CTPOP, N->getDebugLoc(), VT, N0);
3394 SDValue DAGCombiner::visitSELECT(SDNode *N) {
3395 SDValue N0 = N->getOperand(0);
3396 SDValue N1 = N->getOperand(1);
3397 SDValue N2 = N->getOperand(2);
3398 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
3399 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
3400 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2);
3401 EVT VT = N->getValueType(0);
3402 EVT VT0 = N0.getValueType();
3404 // fold (select C, X, X) -> X
3407 // fold (select true, X, Y) -> X
3408 if (N0C && !N0C->isNullValue())
3410 // fold (select false, X, Y) -> Y
3411 if (N0C && N0C->isNullValue())
3413 // fold (select C, 1, X) -> (or C, X)
3414 if (VT == MVT::i1 && N1C && N1C->getAPIntValue() == 1)
3415 return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N0, N2);
3416 // fold (select C, 0, 1) -> (xor C, 1)
3417 if (VT.isInteger() &&
3420 TLI.getBooleanContents() == TargetLowering::ZeroOrOneBooleanContent)) &&
3421 N1C && N2C && N1C->isNullValue() && N2C->getAPIntValue() == 1) {
3424 return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT0,
3425 N0, DAG.getConstant(1, VT0));
3426 XORNode = DAG.getNode(ISD::XOR, N0.getDebugLoc(), VT0,
3427 N0, DAG.getConstant(1, VT0));
3428 AddToWorkList(XORNode.getNode());
3430 return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, XORNode);
3431 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, XORNode);
3433 // fold (select C, 0, X) -> (and (not C), X)
3434 if (VT == VT0 && VT == MVT::i1 && N1C && N1C->isNullValue()) {
3435 SDValue NOTNode = DAG.getNOT(N0.getDebugLoc(), N0, VT);
3436 AddToWorkList(NOTNode.getNode());
3437 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, NOTNode, N2);
3439 // fold (select C, X, 1) -> (or (not C), X)
3440 if (VT == VT0 && VT == MVT::i1 && N2C && N2C->getAPIntValue() == 1) {
3441 SDValue NOTNode = DAG.getNOT(N0.getDebugLoc(), N0, VT);
3442 AddToWorkList(NOTNode.getNode());
3443 return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, NOTNode, N1);
3445 // fold (select C, X, 0) -> (and C, X)
3446 if (VT == MVT::i1 && N2C && N2C->isNullValue())
3447 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0, N1);
3448 // fold (select X, X, Y) -> (or X, Y)
3449 // fold (select X, 1, Y) -> (or X, Y)
3450 if (VT == MVT::i1 && (N0 == N1 || (N1C && N1C->getAPIntValue() == 1)))
3451 return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N0, N2);
3452 // fold (select X, Y, X) -> (and X, Y)
3453 // fold (select X, Y, 0) -> (and X, Y)
3454 if (VT == MVT::i1 && (N0 == N2 || (N2C && N2C->getAPIntValue() == 0)))
3455 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0, N1);
3457 // If we can fold this based on the true/false value, do so.
3458 if (SimplifySelectOps(N, N1, N2))
3459 return SDValue(N, 0); // Don't revisit N.
3461 // fold selects based on a setcc into other things, such as min/max/abs
3462 if (N0.getOpcode() == ISD::SETCC) {
3464 // Check against MVT::Other for SELECT_CC, which is a workaround for targets
3465 // having to say they don't support SELECT_CC on every type the DAG knows
3466 // about, since there is no way to mark an opcode illegal at all value types
3467 if (TLI.isOperationLegalOrCustom(ISD::SELECT_CC, MVT::Other) &&
3468 TLI.isOperationLegalOrCustom(ISD::SELECT_CC, VT))
3469 return DAG.getNode(ISD::SELECT_CC, N->getDebugLoc(), VT,
3470 N0.getOperand(0), N0.getOperand(1),
3471 N1, N2, N0.getOperand(2));
3472 return SimplifySelect(N->getDebugLoc(), N0, N1, N2);
3478 SDValue DAGCombiner::visitSELECT_CC(SDNode *N) {
3479 SDValue N0 = N->getOperand(0);
3480 SDValue N1 = N->getOperand(1);
3481 SDValue N2 = N->getOperand(2);
3482 SDValue N3 = N->getOperand(3);
3483 SDValue N4 = N->getOperand(4);
3484 ISD::CondCode CC = cast<CondCodeSDNode>(N4)->get();
3486 // fold select_cc lhs, rhs, x, x, cc -> x
3490 // Determine if the condition we're dealing with is constant
3491 SDValue SCC = SimplifySetCC(TLI.getSetCCResultType(N0.getValueType()),
3492 N0, N1, CC, N->getDebugLoc(), false);
3493 if (SCC.getNode()) AddToWorkList(SCC.getNode());
3495 if (ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.getNode())) {
3496 if (!SCCC->isNullValue())
3497 return N2; // cond always true -> true val
3499 return N3; // cond always false -> false val
3502 // Fold to a simpler select_cc
3503 if (SCC.getNode() && SCC.getOpcode() == ISD::SETCC)
3504 return DAG.getNode(ISD::SELECT_CC, N->getDebugLoc(), N2.getValueType(),
3505 SCC.getOperand(0), SCC.getOperand(1), N2, N3,
3508 // If we can fold this based on the true/false value, do so.
3509 if (SimplifySelectOps(N, N2, N3))
3510 return SDValue(N, 0); // Don't revisit N.
3512 // fold select_cc into other things, such as min/max/abs
3513 return SimplifySelectCC(N->getDebugLoc(), N0, N1, N2, N3, CC);
3516 SDValue DAGCombiner::visitSETCC(SDNode *N) {
3517 return SimplifySetCC(N->getValueType(0), N->getOperand(0), N->getOperand(1),
3518 cast<CondCodeSDNode>(N->getOperand(2))->get(),
3522 // ExtendUsesToFormExtLoad - Trying to extend uses of a load to enable this:
3523 // "fold ({s|z|a}ext (load x)) -> ({s|z|a}ext (truncate ({s|z|a}extload x)))"
3524 // transformation. Returns true if extension are possible and the above
3525 // mentioned transformation is profitable.
3526 static bool ExtendUsesToFormExtLoad(SDNode *N, SDValue N0,
3528 SmallVector<SDNode*, 4> &ExtendNodes,
3529 const TargetLowering &TLI) {
3530 bool HasCopyToRegUses = false;
3531 bool isTruncFree = TLI.isTruncateFree(N->getValueType(0), N0.getValueType());
3532 for (SDNode::use_iterator UI = N0.getNode()->use_begin(),
3533 UE = N0.getNode()->use_end();
3538 if (UI.getUse().getResNo() != N0.getResNo())
3540 // FIXME: Only extend SETCC N, N and SETCC N, c for now.
3541 if (ExtOpc != ISD::ANY_EXTEND && User->getOpcode() == ISD::SETCC) {
3542 ISD::CondCode CC = cast<CondCodeSDNode>(User->getOperand(2))->get();
3543 if (ExtOpc == ISD::ZERO_EXTEND && ISD::isSignedIntSetCC(CC))
3544 // Sign bits will be lost after a zext.
3547 for (unsigned i = 0; i != 2; ++i) {
3548 SDValue UseOp = User->getOperand(i);
3551 if (!isa<ConstantSDNode>(UseOp))
3556 ExtendNodes.push_back(User);
3559 // If truncates aren't free and there are users we can't
3560 // extend, it isn't worthwhile.
3563 // Remember if this value is live-out.
3564 if (User->getOpcode() == ISD::CopyToReg)
3565 HasCopyToRegUses = true;
3568 if (HasCopyToRegUses) {
3569 bool BothLiveOut = false;
3570 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end();
3572 SDUse &Use = UI.getUse();
3573 if (Use.getResNo() == 0 && Use.getUser()->getOpcode() == ISD::CopyToReg) {
3579 // Both unextended and extended values are live out. There had better be
3580 // a good reason for the transformation.
3581 return ExtendNodes.size();
3586 SDValue DAGCombiner::visitSIGN_EXTEND(SDNode *N) {
3587 SDValue N0 = N->getOperand(0);
3588 EVT VT = N->getValueType(0);
3590 // fold (sext c1) -> c1
3591 if (isa<ConstantSDNode>(N0))
3592 return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, N0);
3594 // fold (sext (sext x)) -> (sext x)
3595 // fold (sext (aext x)) -> (sext x)
3596 if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND)
3597 return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT,
3600 if (N0.getOpcode() == ISD::TRUNCATE) {
3601 // fold (sext (truncate (load x))) -> (sext (smaller load x))
3602 // fold (sext (truncate (srl (load x), c))) -> (sext (smaller load (x+c/n)))
3603 SDValue NarrowLoad = ReduceLoadWidth(N0.getNode());
3604 if (NarrowLoad.getNode()) {
3605 SDNode* oye = N0.getNode()->getOperand(0).getNode();
3606 if (NarrowLoad.getNode() != N0.getNode()) {
3607 CombineTo(N0.getNode(), NarrowLoad);
3608 // CombineTo deleted the truncate, if needed, but not what's under it.
3611 return SDValue(N, 0); // Return N so it doesn't get rechecked!
3614 // See if the value being truncated is already sign extended. If so, just
3615 // eliminate the trunc/sext pair.
3616 SDValue Op = N0.getOperand(0);
3617 unsigned OpBits = Op.getValueType().getScalarType().getSizeInBits();
3618 unsigned MidBits = N0.getValueType().getScalarType().getSizeInBits();
3619 unsigned DestBits = VT.getScalarType().getSizeInBits();
3620 unsigned NumSignBits = DAG.ComputeNumSignBits(Op);
3622 if (OpBits == DestBits) {
3623 // Op is i32, Mid is i8, and Dest is i32. If Op has more than 24 sign
3624 // bits, it is already ready.
3625 if (NumSignBits > DestBits-MidBits)
3627 } else if (OpBits < DestBits) {
3628 // Op is i32, Mid is i8, and Dest is i64. If Op has more than 24 sign
3629 // bits, just sext from i32.
3630 if (NumSignBits > OpBits-MidBits)
3631 return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, Op);
3633 // Op is i64, Mid is i8, and Dest is i32. If Op has more than 56 sign
3634 // bits, just truncate to i32.
3635 if (NumSignBits > OpBits-MidBits)
3636 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, Op);
3639 // fold (sext (truncate x)) -> (sextinreg x).
3640 if (!LegalOperations || TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG,
3641 N0.getValueType())) {
3642 if (OpBits < DestBits)
3643 Op = DAG.getNode(ISD::ANY_EXTEND, N0.getDebugLoc(), VT, Op);
3644 else if (OpBits > DestBits)
3645 Op = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), VT, Op);
3646 return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT, Op,
3647 DAG.getValueType(N0.getValueType()));
3651 // fold (sext (load x)) -> (sext (truncate (sextload x)))
3652 if (ISD::isNON_EXTLoad(N0.getNode()) &&
3653 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
3654 TLI.isLoadExtLegal(ISD::SEXTLOAD, N0.getValueType()))) {
3655 bool DoXform = true;
3656 SmallVector<SDNode*, 4> SetCCs;
3657 if (!N0.hasOneUse())
3658 DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::SIGN_EXTEND, SetCCs, TLI);
3660 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
3661 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N->getDebugLoc(),
3663 LN0->getBasePtr(), LN0->getPointerInfo(),
3665 LN0->isVolatile(), LN0->isNonTemporal(),
3666 LN0->getAlignment());
3667 CombineTo(N, ExtLoad);
3668 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(),
3669 N0.getValueType(), ExtLoad);
3670 CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1));
3672 // Extend SetCC uses if necessary.
3673 for (unsigned i = 0, e = SetCCs.size(); i != e; ++i) {
3674 SDNode *SetCC = SetCCs[i];
3675 SmallVector<SDValue, 4> Ops;
3677 for (unsigned j = 0; j != 2; ++j) {
3678 SDValue SOp = SetCC->getOperand(j);
3680 Ops.push_back(ExtLoad);
3682 Ops.push_back(DAG.getNode(ISD::SIGN_EXTEND,
3683 N->getDebugLoc(), VT, SOp));
3686 Ops.push_back(SetCC->getOperand(2));
3687 CombineTo(SetCC, DAG.getNode(ISD::SETCC, N->getDebugLoc(),
3688 SetCC->getValueType(0),
3689 &Ops[0], Ops.size()));
3692 return SDValue(N, 0); // Return N so it doesn't get rechecked!
3696 // fold (sext (sextload x)) -> (sext (truncate (sextload x)))
3697 // fold (sext ( extload x)) -> (sext (truncate (sextload x)))
3698 if ((ISD::isSEXTLoad(N0.getNode()) || ISD::isEXTLoad(N0.getNode())) &&
3699 ISD::isUNINDEXEDLoad(N0.getNode()) && N0.hasOneUse()) {
3700 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
3701 EVT MemVT = LN0->getMemoryVT();
3702 if ((!LegalOperations && !LN0->isVolatile()) ||
3703 TLI.isLoadExtLegal(ISD::SEXTLOAD, MemVT)) {
3704 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N->getDebugLoc(),
3706 LN0->getBasePtr(), LN0->getPointerInfo(),
3708 LN0->isVolatile(), LN0->isNonTemporal(),
3709 LN0->getAlignment());
3710 CombineTo(N, ExtLoad);
3711 CombineTo(N0.getNode(),
3712 DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(),
3713 N0.getValueType(), ExtLoad),
3714 ExtLoad.getValue(1));
3715 return SDValue(N, 0); // Return N so it doesn't get rechecked!
3719 if (N0.getOpcode() == ISD::SETCC) {
3720 // sext(setcc) -> sext_in_reg(vsetcc) for vectors.
3721 // Only do this before legalize for now.
3722 if (VT.isVector() && !LegalOperations) {
3723 EVT N0VT = N0.getOperand(0).getValueType();
3724 // We know that the # elements of the results is the same as the
3725 // # elements of the compare (and the # elements of the compare result
3726 // for that matter). Check to see that they are the same size. If so,
3727 // we know that the element size of the sext'd result matches the
3728 // element size of the compare operands.
3729 if (VT.getSizeInBits() == N0VT.getSizeInBits())
3730 return DAG.getVSetCC(N->getDebugLoc(), VT, N0.getOperand(0),
3732 cast<CondCodeSDNode>(N0.getOperand(2))->get());
3733 // If the desired elements are smaller or larger than the source
3734 // elements we can use a matching integer vector type and then
3735 // truncate/sign extend
3737 EVT MatchingElementType =
3738 EVT::getIntegerVT(*DAG.getContext(),
3739 N0VT.getScalarType().getSizeInBits());
3740 EVT MatchingVectorType =
3741 EVT::getVectorVT(*DAG.getContext(), MatchingElementType,
3742 N0VT.getVectorNumElements());
3744 DAG.getVSetCC(N->getDebugLoc(), MatchingVectorType, N0.getOperand(0),
3746 cast<CondCodeSDNode>(N0.getOperand(2))->get());
3747 return DAG.getSExtOrTrunc(VsetCC, N->getDebugLoc(), VT);
3751 // sext(setcc x, y, cc) -> (select_cc x, y, -1, 0, cc)
3752 unsigned ElementWidth = VT.getScalarType().getSizeInBits();
3754 DAG.getConstant(APInt::getAllOnesValue(ElementWidth), VT);
3756 SimplifySelectCC(N->getDebugLoc(), N0.getOperand(0), N0.getOperand(1),
3757 NegOne, DAG.getConstant(0, VT),
3758 cast<CondCodeSDNode>(N0.getOperand(2))->get(), true);
3759 if (SCC.getNode()) return SCC;
3760 if (!LegalOperations ||
3761 TLI.isOperationLegal(ISD::SETCC, TLI.getSetCCResultType(VT)))
3762 return DAG.getNode(ISD::SELECT, N->getDebugLoc(), VT,
3763 DAG.getSetCC(N->getDebugLoc(),
3764 TLI.getSetCCResultType(VT),
3765 N0.getOperand(0), N0.getOperand(1),
3766 cast<CondCodeSDNode>(N0.getOperand(2))->get()),
3767 NegOne, DAG.getConstant(0, VT));
3770 // fold (sext x) -> (zext x) if the sign bit is known zero.
3771 if ((!LegalOperations || TLI.isOperationLegal(ISD::ZERO_EXTEND, VT)) &&
3772 DAG.SignBitIsZero(N0))
3773 return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, N0);
3778 SDValue DAGCombiner::visitZERO_EXTEND(SDNode *N) {
3779 SDValue N0 = N->getOperand(0);
3780 EVT VT = N->getValueType(0);
3782 // fold (zext c1) -> c1
3783 if (isa<ConstantSDNode>(N0))
3784 return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, N0);
3785 // fold (zext (zext x)) -> (zext x)
3786 // fold (zext (aext x)) -> (zext x)
3787 if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND)
3788 return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT,
3791 // fold (zext (truncate (load x))) -> (zext (smaller load x))
3792 // fold (zext (truncate (srl (load x), c))) -> (zext (small load (x+c/n)))
3793 if (N0.getOpcode() == ISD::TRUNCATE) {
3794 SDValue NarrowLoad = ReduceLoadWidth(N0.getNode());
3795 if (NarrowLoad.getNode()) {
3796 SDNode* oye = N0.getNode()->getOperand(0).getNode();
3797 if (NarrowLoad.getNode() != N0.getNode()) {
3798 CombineTo(N0.getNode(), NarrowLoad);
3799 // CombineTo deleted the truncate, if needed, but not what's under it.
3802 return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, NarrowLoad);
3806 // fold (zext (truncate x)) -> (and x, mask)
3807 if (N0.getOpcode() == ISD::TRUNCATE &&
3808 (!LegalOperations || TLI.isOperationLegal(ISD::AND, VT))) {
3810 // fold (zext (truncate (load x))) -> (zext (smaller load x))
3811 // fold (zext (truncate (srl (load x), c))) -> (zext (smaller load (x+c/n)))
3812 SDValue NarrowLoad = ReduceLoadWidth(N0.getNode());
3813 if (NarrowLoad.getNode()) {
3814 SDNode* oye = N0.getNode()->getOperand(0).getNode();
3815 if (NarrowLoad.getNode() != N0.getNode()) {
3816 CombineTo(N0.getNode(), NarrowLoad);
3817 // CombineTo deleted the truncate, if needed, but not what's under it.
3820 return SDValue(N, 0); // Return N so it doesn't get rechecked!
3823 SDValue Op = N0.getOperand(0);
3824 if (Op.getValueType().bitsLT(VT)) {
3825 Op = DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, Op);
3826 } else if (Op.getValueType().bitsGT(VT)) {
3827 Op = DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, Op);
3829 return DAG.getZeroExtendInReg(Op, N->getDebugLoc(),
3830 N0.getValueType().getScalarType());
3833 // Fold (zext (and (trunc x), cst)) -> (and x, cst),
3834 // if either of the casts is not free.
3835 if (N0.getOpcode() == ISD::AND &&
3836 N0.getOperand(0).getOpcode() == ISD::TRUNCATE &&
3837 N0.getOperand(1).getOpcode() == ISD::Constant &&
3838 (!TLI.isTruncateFree(N0.getOperand(0).getOperand(0).getValueType(),
3839 N0.getValueType()) ||
3840 !TLI.isZExtFree(N0.getValueType(), VT))) {
3841 SDValue X = N0.getOperand(0).getOperand(0);
3842 if (X.getValueType().bitsLT(VT)) {
3843 X = DAG.getNode(ISD::ANY_EXTEND, X.getDebugLoc(), VT, X);
3844 } else if (X.getValueType().bitsGT(VT)) {
3845 X = DAG.getNode(ISD::TRUNCATE, X.getDebugLoc(), VT, X);
3847 APInt Mask = cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue();
3848 Mask = Mask.zext(VT.getSizeInBits());
3849 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT,
3850 X, DAG.getConstant(Mask, VT));
3853 // fold (zext (load x)) -> (zext (truncate (zextload x)))
3854 if (ISD::isNON_EXTLoad(N0.getNode()) &&
3855 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
3856 TLI.isLoadExtLegal(ISD::ZEXTLOAD, N0.getValueType()))) {
3857 bool DoXform = true;
3858 SmallVector<SDNode*, 4> SetCCs;
3859 if (!N0.hasOneUse())
3860 DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::ZERO_EXTEND, SetCCs, TLI);
3862 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
3863 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N->getDebugLoc(),
3865 LN0->getBasePtr(), LN0->getPointerInfo(),
3867 LN0->isVolatile(), LN0->isNonTemporal(),
3868 LN0->getAlignment());
3869 CombineTo(N, ExtLoad);
3870 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(),
3871 N0.getValueType(), ExtLoad);
3872 CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1));
3874 // Extend SetCC uses if necessary.
3875 for (unsigned i = 0, e = SetCCs.size(); i != e; ++i) {
3876 SDNode *SetCC = SetCCs[i];
3877 SmallVector<SDValue, 4> Ops;
3879 for (unsigned j = 0; j != 2; ++j) {
3880 SDValue SOp = SetCC->getOperand(j);
3882 Ops.push_back(ExtLoad);
3884 Ops.push_back(DAG.getNode(ISD::ZERO_EXTEND,
3885 N->getDebugLoc(), VT, SOp));
3888 Ops.push_back(SetCC->getOperand(2));
3889 CombineTo(SetCC, DAG.getNode(ISD::SETCC, N->getDebugLoc(),
3890 SetCC->getValueType(0),
3891 &Ops[0], Ops.size()));
3894 return SDValue(N, 0); // Return N so it doesn't get rechecked!
3898 // fold (zext (zextload x)) -> (zext (truncate (zextload x)))
3899 // fold (zext ( extload x)) -> (zext (truncate (zextload x)))
3900 if ((ISD::isZEXTLoad(N0.getNode()) || ISD::isEXTLoad(N0.getNode())) &&
3901 ISD::isUNINDEXEDLoad(N0.getNode()) && N0.hasOneUse()) {
3902 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
3903 EVT MemVT = LN0->getMemoryVT();
3904 if ((!LegalOperations && !LN0->isVolatile()) ||
3905 TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT)) {
3906 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N->getDebugLoc(),
3908 LN0->getBasePtr(), LN0->getPointerInfo(),
3910 LN0->isVolatile(), LN0->isNonTemporal(),
3911 LN0->getAlignment());
3912 CombineTo(N, ExtLoad);
3913 CombineTo(N0.getNode(),
3914 DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), N0.getValueType(),
3916 ExtLoad.getValue(1));
3917 return SDValue(N, 0); // Return N so it doesn't get rechecked!
3921 if (N0.getOpcode() == ISD::SETCC) {
3922 if (!LegalOperations && VT.isVector()) {
3923 // zext(setcc) -> (and (vsetcc), (1, 1, ...) for vectors.
3924 // Only do this before legalize for now.
3925 EVT N0VT = N0.getOperand(0).getValueType();
3926 EVT EltVT = VT.getVectorElementType();
3927 SmallVector<SDValue,8> OneOps(VT.getVectorNumElements(),
3928 DAG.getConstant(1, EltVT));
3929 if (VT.getSizeInBits() == N0VT.getSizeInBits()) {
3930 // We know that the # elements of the results is the same as the
3931 // # elements of the compare (and the # elements of the compare result
3932 // for that matter). Check to see that they are the same size. If so,
3933 // we know that the element size of the sext'd result matches the
3934 // element size of the compare operands.
3935 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT,
3936 DAG.getVSetCC(N->getDebugLoc(), VT, N0.getOperand(0),
3938 cast<CondCodeSDNode>(N0.getOperand(2))->get()),
3939 DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), VT,
3940 &OneOps[0], OneOps.size()));
3942 // If the desired elements are smaller or larger than the source
3943 // elements we can use a matching integer vector type and then
3944 // truncate/sign extend
3945 EVT MatchingElementType =
3946 EVT::getIntegerVT(*DAG.getContext(),
3947 N0VT.getScalarType().getSizeInBits());
3948 EVT MatchingVectorType =
3949 EVT::getVectorVT(*DAG.getContext(), MatchingElementType,
3950 N0VT.getVectorNumElements());
3952 DAG.getVSetCC(N->getDebugLoc(), MatchingVectorType, N0.getOperand(0),
3954 cast<CondCodeSDNode>(N0.getOperand(2))->get());
3955 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT,
3956 DAG.getSExtOrTrunc(VsetCC, N->getDebugLoc(), VT),
3957 DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), VT,
3958 &OneOps[0], OneOps.size()));
3962 // zext(setcc x,y,cc) -> select_cc x, y, 1, 0, cc
3964 SimplifySelectCC(N->getDebugLoc(), N0.getOperand(0), N0.getOperand(1),
3965 DAG.getConstant(1, VT), DAG.getConstant(0, VT),
3966 cast<CondCodeSDNode>(N0.getOperand(2))->get(), true);
3967 if (SCC.getNode()) return SCC;
3970 // (zext (shl (zext x), cst)) -> (shl (zext x), cst)
3971 if ((N0.getOpcode() == ISD::SHL || N0.getOpcode() == ISD::SRL) &&
3972 isa<ConstantSDNode>(N0.getOperand(1)) &&
3973 N0.getOperand(0).getOpcode() == ISD::ZERO_EXTEND &&
3975 if (N0.getOpcode() == ISD::SHL) {
3976 // If the original shl may be shifting out bits, do not perform this
3978 unsigned ShAmt = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue();
3979 unsigned KnownZeroBits = N0.getOperand(0).getValueType().getSizeInBits() -
3980 N0.getOperand(0).getOperand(0).getValueType().getSizeInBits();
3981 if (ShAmt > KnownZeroBits)
3984 DebugLoc dl = N->getDebugLoc();
3985 return DAG.getNode(N0.getOpcode(), dl, VT,
3986 DAG.getNode(ISD::ZERO_EXTEND, dl, VT, N0.getOperand(0)),
3987 DAG.getNode(ISD::ZERO_EXTEND, dl,
3988 N0.getOperand(1).getValueType(),
3995 SDValue DAGCombiner::visitANY_EXTEND(SDNode *N) {
3996 SDValue N0 = N->getOperand(0);
3997 EVT VT = N->getValueType(0);
3999 // fold (aext c1) -> c1
4000 if (isa<ConstantSDNode>(N0))
4001 return DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, N0);
4002 // fold (aext (aext x)) -> (aext x)
4003 // fold (aext (zext x)) -> (zext x)
4004 // fold (aext (sext x)) -> (sext x)
4005 if (N0.getOpcode() == ISD::ANY_EXTEND ||
4006 N0.getOpcode() == ISD::ZERO_EXTEND ||
4007 N0.getOpcode() == ISD::SIGN_EXTEND)
4008 return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT, N0.getOperand(0));
4010 // fold (aext (truncate (load x))) -> (aext (smaller load x))
4011 // fold (aext (truncate (srl (load x), c))) -> (aext (small load (x+c/n)))
4012 if (N0.getOpcode() == ISD::TRUNCATE) {
4013 SDValue NarrowLoad = ReduceLoadWidth(N0.getNode());
4014 if (NarrowLoad.getNode()) {
4015 SDNode* oye = N0.getNode()->getOperand(0).getNode();
4016 if (NarrowLoad.getNode() != N0.getNode()) {
4017 CombineTo(N0.getNode(), NarrowLoad);
4018 // CombineTo deleted the truncate, if needed, but not what's under it.
4021 return DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, NarrowLoad);
4025 // fold (aext (truncate x))
4026 if (N0.getOpcode() == ISD::TRUNCATE) {
4027 SDValue TruncOp = N0.getOperand(0);
4028 if (TruncOp.getValueType() == VT)
4029 return TruncOp; // x iff x size == zext size.
4030 if (TruncOp.getValueType().bitsGT(VT))
4031 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, TruncOp);
4032 return DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, TruncOp);
4035 // Fold (aext (and (trunc x), cst)) -> (and x, cst)
4036 // if the trunc is not free.
4037 if (N0.getOpcode() == ISD::AND &&
4038 N0.getOperand(0).getOpcode() == ISD::TRUNCATE &&
4039 N0.getOperand(1).getOpcode() == ISD::Constant &&
4040 !TLI.isTruncateFree(N0.getOperand(0).getOperand(0).getValueType(),
4041 N0.getValueType())) {
4042 SDValue X = N0.getOperand(0).getOperand(0);
4043 if (X.getValueType().bitsLT(VT)) {
4044 X = DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, X);
4045 } else if (X.getValueType().bitsGT(VT)) {
4046 X = DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, X);
4048 APInt Mask = cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue();
4049 Mask = Mask.zext(VT.getSizeInBits());
4050 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT,
4051 X, DAG.getConstant(Mask, VT));
4054 // fold (aext (load x)) -> (aext (truncate (extload x)))
4055 if (ISD::isNON_EXTLoad(N0.getNode()) &&
4056 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
4057 TLI.isLoadExtLegal(ISD::EXTLOAD, N0.getValueType()))) {
4058 bool DoXform = true;
4059 SmallVector<SDNode*, 4> SetCCs;
4060 if (!N0.hasOneUse())
4061 DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::ANY_EXTEND, SetCCs, TLI);
4063 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
4064 SDValue ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, VT, N->getDebugLoc(),
4066 LN0->getBasePtr(), LN0->getPointerInfo(),
4068 LN0->isVolatile(), LN0->isNonTemporal(),
4069 LN0->getAlignment());
4070 CombineTo(N, ExtLoad);
4071 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(),
4072 N0.getValueType(), ExtLoad);
4073 CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1));
4075 // Extend SetCC uses if necessary.
4076 for (unsigned i = 0, e = SetCCs.size(); i != e; ++i) {
4077 SDNode *SetCC = SetCCs[i];
4078 SmallVector<SDValue, 4> Ops;
4080 for (unsigned j = 0; j != 2; ++j) {
4081 SDValue SOp = SetCC->getOperand(j);
4083 Ops.push_back(ExtLoad);
4085 Ops.push_back(DAG.getNode(ISD::ANY_EXTEND,
4086 N->getDebugLoc(), VT, SOp));
4089 Ops.push_back(SetCC->getOperand(2));
4090 CombineTo(SetCC, DAG.getNode(ISD::SETCC, N->getDebugLoc(),
4091 SetCC->getValueType(0),
4092 &Ops[0], Ops.size()));
4095 return SDValue(N, 0); // Return N so it doesn't get rechecked!
4099 // fold (aext (zextload x)) -> (aext (truncate (zextload x)))
4100 // fold (aext (sextload x)) -> (aext (truncate (sextload x)))
4101 // fold (aext ( extload x)) -> (aext (truncate (extload x)))
4102 if (N0.getOpcode() == ISD::LOAD &&
4103 !ISD::isNON_EXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) &&
4105 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
4106 EVT MemVT = LN0->getMemoryVT();
4107 SDValue ExtLoad = DAG.getExtLoad(LN0->getExtensionType(), VT,
4109 LN0->getChain(), LN0->getBasePtr(),
4110 LN0->getPointerInfo(), MemVT,
4111 LN0->isVolatile(), LN0->isNonTemporal(),
4112 LN0->getAlignment());
4113 CombineTo(N, ExtLoad);
4114 CombineTo(N0.getNode(),
4115 DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(),
4116 N0.getValueType(), ExtLoad),
4117 ExtLoad.getValue(1));
4118 return SDValue(N, 0); // Return N so it doesn't get rechecked!
4121 if (N0.getOpcode() == ISD::SETCC) {
4122 // aext(setcc) -> sext_in_reg(vsetcc) for vectors.
4123 // Only do this before legalize for now.
4124 if (VT.isVector() && !LegalOperations) {
4125 EVT N0VT = N0.getOperand(0).getValueType();
4126 // We know that the # elements of the results is the same as the
4127 // # elements of the compare (and the # elements of the compare result
4128 // for that matter). Check to see that they are the same size. If so,
4129 // we know that the element size of the sext'd result matches the
4130 // element size of the compare operands.
4131 if (VT.getSizeInBits() == N0VT.getSizeInBits())
4132 return DAG.getVSetCC(N->getDebugLoc(), VT, N0.getOperand(0),
4134 cast<CondCodeSDNode>(N0.getOperand(2))->get());
4135 // If the desired elements are smaller or larger than the source
4136 // elements we can use a matching integer vector type and then
4137 // truncate/sign extend
4139 EVT MatchingElementType =
4140 EVT::getIntegerVT(*DAG.getContext(),
4141 N0VT.getScalarType().getSizeInBits());
4142 EVT MatchingVectorType =
4143 EVT::getVectorVT(*DAG.getContext(), MatchingElementType,
4144 N0VT.getVectorNumElements());
4146 DAG.getVSetCC(N->getDebugLoc(), MatchingVectorType, N0.getOperand(0),
4148 cast<CondCodeSDNode>(N0.getOperand(2))->get());
4149 return DAG.getSExtOrTrunc(VsetCC, N->getDebugLoc(), VT);
4153 // aext(setcc x,y,cc) -> select_cc x, y, 1, 0, cc
4155 SimplifySelectCC(N->getDebugLoc(), N0.getOperand(0), N0.getOperand(1),
4156 DAG.getConstant(1, VT), DAG.getConstant(0, VT),
4157 cast<CondCodeSDNode>(N0.getOperand(2))->get(), true);
4165 /// GetDemandedBits - See if the specified operand can be simplified with the
4166 /// knowledge that only the bits specified by Mask are used. If so, return the
4167 /// simpler operand, otherwise return a null SDValue.
4168 SDValue DAGCombiner::GetDemandedBits(SDValue V, const APInt &Mask) {
4169 switch (V.getOpcode()) {
4173 // If the LHS or RHS don't contribute bits to the or, drop them.
4174 if (DAG.MaskedValueIsZero(V.getOperand(0), Mask))
4175 return V.getOperand(1);
4176 if (DAG.MaskedValueIsZero(V.getOperand(1), Mask))
4177 return V.getOperand(0);
4180 // Only look at single-use SRLs.
4181 if (!V.getNode()->hasOneUse())
4183 if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(V.getOperand(1))) {
4184 // See if we can recursively simplify the LHS.
4185 unsigned Amt = RHSC->getZExtValue();
4187 // Watch out for shift count overflow though.
4188 if (Amt >= Mask.getBitWidth()) break;
4189 APInt NewMask = Mask << Amt;
4190 SDValue SimplifyLHS = GetDemandedBits(V.getOperand(0), NewMask);
4191 if (SimplifyLHS.getNode())
4192 return DAG.getNode(ISD::SRL, V.getDebugLoc(), V.getValueType(),
4193 SimplifyLHS, V.getOperand(1));
4199 /// ReduceLoadWidth - If the result of a wider load is shifted to right of N
4200 /// bits and then truncated to a narrower type and where N is a multiple
4201 /// of number of bits of the narrower type, transform it to a narrower load
4202 /// from address + N / num of bits of new type. If the result is to be
4203 /// extended, also fold the extension to form a extending load.
4204 SDValue DAGCombiner::ReduceLoadWidth(SDNode *N) {
4205 unsigned Opc = N->getOpcode();
4207 ISD::LoadExtType ExtType = ISD::NON_EXTLOAD;
4208 SDValue N0 = N->getOperand(0);
4209 EVT VT = N->getValueType(0);
4212 // This transformation isn't valid for vector loads.
4216 // Special case: SIGN_EXTEND_INREG is basically truncating to ExtVT then
4218 if (Opc == ISD::SIGN_EXTEND_INREG) {
4219 ExtType = ISD::SEXTLOAD;
4220 ExtVT = cast<VTSDNode>(N->getOperand(1))->getVT();
4221 if (LegalOperations && !TLI.isLoadExtLegal(ISD::SEXTLOAD, ExtVT))
4223 } else if (Opc == ISD::SRL) {
4224 // Another special-case: SRL is basically zero-extending a narrower value.
4225 ExtType = ISD::ZEXTLOAD;
4227 ConstantSDNode *N01 = dyn_cast<ConstantSDNode>(N0.getOperand(1));
4228 if (!N01) return SDValue();
4229 ExtVT = EVT::getIntegerVT(*DAG.getContext(),
4230 VT.getSizeInBits() - N01->getZExtValue());
4233 unsigned EVTBits = ExtVT.getSizeInBits();
4235 // Do not generate loads of non-round integer types since these can
4236 // be expensive (and would be wrong if the type is not byte sized).
4237 if (!ExtVT.isRound())
4241 if (N0.getOpcode() == ISD::SRL && N0.hasOneUse()) {
4242 if (ConstantSDNode *N01 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
4243 ShAmt = N01->getZExtValue();
4244 // Is the shift amount a multiple of size of VT?
4245 if ((ShAmt & (EVTBits-1)) == 0) {
4246 N0 = N0.getOperand(0);
4247 // Is the load width a multiple of size of VT?
4248 if ((N0.getValueType().getSizeInBits() & (EVTBits-1)) != 0)
4252 // At this point, we must have a load or else we can't do the transform.
4253 if (!isa<LoadSDNode>(N0)) return SDValue();
4255 // If the shift amount is larger than the input type then we're not
4256 // accessing any of the loaded bytes. If the load was a zextload/extload
4257 // then the result of the shift+trunc is zero/undef (handled elsewhere).
4258 // If the load was a sextload then the result is a splat of the sign bit
4259 // of the extended byte. This is not worth optimizing for.
4260 if (ShAmt >= cast<LoadSDNode>(N0)->getMemoryVT().getSizeInBits())
4265 // If the load is shifted left (and the result isn't shifted back right),
4266 // we can fold the truncate through the shift.
4267 unsigned ShLeftAmt = 0;
4268 if (ShAmt == 0 && N0.getOpcode() == ISD::SHL && N0.hasOneUse() &&
4269 ExtVT == VT && TLI.isNarrowingProfitable(N0.getValueType(), VT)) {
4270 if (ConstantSDNode *N01 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
4271 ShLeftAmt = N01->getZExtValue();
4272 N0 = N0.getOperand(0);
4276 // If we haven't found a load, we can't narrow it. Don't transform one with
4277 // multiple uses, this would require adding a new load.
4278 if (!isa<LoadSDNode>(N0) || !N0.hasOneUse() ||
4279 // Don't change the width of a volatile load.
4280 cast<LoadSDNode>(N0)->isVolatile())
4283 // Verify that we are actually reducing a load width here.
4284 if (cast<LoadSDNode>(N0)->getMemoryVT().getSizeInBits() < EVTBits)
4287 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
4288 EVT PtrType = N0.getOperand(1).getValueType();
4290 // For big endian targets, we need to adjust the offset to the pointer to
4291 // load the correct bytes.
4292 if (TLI.isBigEndian()) {
4293 unsigned LVTStoreBits = LN0->getMemoryVT().getStoreSizeInBits();
4294 unsigned EVTStoreBits = ExtVT.getStoreSizeInBits();
4295 ShAmt = LVTStoreBits - EVTStoreBits - ShAmt;
4298 uint64_t PtrOff = ShAmt / 8;
4299 unsigned NewAlign = MinAlign(LN0->getAlignment(), PtrOff);
4300 SDValue NewPtr = DAG.getNode(ISD::ADD, LN0->getDebugLoc(),
4301 PtrType, LN0->getBasePtr(),
4302 DAG.getConstant(PtrOff, PtrType));
4303 AddToWorkList(NewPtr.getNode());
4306 if (ExtType == ISD::NON_EXTLOAD)
4307 Load = DAG.getLoad(VT, N0.getDebugLoc(), LN0->getChain(), NewPtr,
4308 LN0->getPointerInfo().getWithOffset(PtrOff),
4309 LN0->isVolatile(), LN0->isNonTemporal(), NewAlign);
4311 Load = DAG.getExtLoad(ExtType, VT, N0.getDebugLoc(), LN0->getChain(),NewPtr,
4312 LN0->getPointerInfo().getWithOffset(PtrOff),
4313 ExtVT, LN0->isVolatile(), LN0->isNonTemporal(),
4316 // Replace the old load's chain with the new load's chain.
4317 WorkListRemover DeadNodes(*this);
4318 DAG.ReplaceAllUsesOfValueWith(N0.getValue(1), Load.getValue(1),
4321 // Shift the result left, if we've swallowed a left shift.
4322 SDValue Result = Load;
4323 if (ShLeftAmt != 0) {
4324 EVT ShImmTy = getShiftAmountTy();
4325 if (!isUIntN(ShImmTy.getSizeInBits(), ShLeftAmt))
4327 Result = DAG.getNode(ISD::SHL, N0.getDebugLoc(), VT,
4328 Result, DAG.getConstant(ShLeftAmt, ShImmTy));
4331 // Return the new loaded value.
4335 SDValue DAGCombiner::visitSIGN_EXTEND_INREG(SDNode *N) {
4336 SDValue N0 = N->getOperand(0);
4337 SDValue N1 = N->getOperand(1);
4338 EVT VT = N->getValueType(0);
4339 EVT EVT = cast<VTSDNode>(N1)->getVT();
4340 unsigned VTBits = VT.getScalarType().getSizeInBits();
4341 unsigned EVTBits = EVT.getScalarType().getSizeInBits();
4343 // fold (sext_in_reg c1) -> c1
4344 if (isa<ConstantSDNode>(N0) || N0.getOpcode() == ISD::UNDEF)
4345 return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT, N0, N1);
4347 // If the input is already sign extended, just drop the extension.
4348 if (DAG.ComputeNumSignBits(N0) >= VTBits-EVTBits+1)
4351 // fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt2
4352 if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
4353 EVT.bitsLT(cast<VTSDNode>(N0.getOperand(1))->getVT())) {
4354 return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT,
4355 N0.getOperand(0), N1);
4358 // fold (sext_in_reg (sext x)) -> (sext x)
4359 // fold (sext_in_reg (aext x)) -> (sext x)
4360 // if x is small enough.
4361 if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) {
4362 SDValue N00 = N0.getOperand(0);
4363 if (N00.getValueType().getScalarType().getSizeInBits() <= EVTBits &&
4364 (!LegalOperations || TLI.isOperationLegal(ISD::SIGN_EXTEND, VT)))
4365 return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, N00, N1);
4368 // fold (sext_in_reg x) -> (zext_in_reg x) if the sign bit is known zero.
4369 if (DAG.MaskedValueIsZero(N0, APInt::getBitsSet(VTBits, EVTBits-1, EVTBits)))
4370 return DAG.getZeroExtendInReg(N0, N->getDebugLoc(), EVT);
4372 // fold operands of sext_in_reg based on knowledge that the top bits are not
4374 if (SimplifyDemandedBits(SDValue(N, 0)))
4375 return SDValue(N, 0);
4377 // fold (sext_in_reg (load x)) -> (smaller sextload x)
4378 // fold (sext_in_reg (srl (load x), c)) -> (smaller sextload (x+c/evtbits))
4379 SDValue NarrowLoad = ReduceLoadWidth(N);
4380 if (NarrowLoad.getNode())
4383 // fold (sext_in_reg (srl X, 24), i8) -> (sra X, 24)
4384 // fold (sext_in_reg (srl X, 23), i8) -> (sra X, 23) iff possible.
4385 // We already fold "(sext_in_reg (srl X, 25), i8) -> srl X, 25" above.
4386 if (N0.getOpcode() == ISD::SRL) {
4387 if (ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(N0.getOperand(1)))
4388 if (ShAmt->getZExtValue()+EVTBits <= VTBits) {
4389 // We can turn this into an SRA iff the input to the SRL is already sign
4391 unsigned InSignBits = DAG.ComputeNumSignBits(N0.getOperand(0));
4392 if (VTBits-(ShAmt->getZExtValue()+EVTBits) < InSignBits)
4393 return DAG.getNode(ISD::SRA, N->getDebugLoc(), VT,
4394 N0.getOperand(0), N0.getOperand(1));
4398 // fold (sext_inreg (extload x)) -> (sextload x)
4399 if (ISD::isEXTLoad(N0.getNode()) &&
4400 ISD::isUNINDEXEDLoad(N0.getNode()) &&
4401 EVT == cast<LoadSDNode>(N0)->getMemoryVT() &&
4402 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
4403 TLI.isLoadExtLegal(ISD::SEXTLOAD, EVT))) {
4404 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
4405 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N->getDebugLoc(),
4407 LN0->getBasePtr(), LN0->getPointerInfo(),
4409 LN0->isVolatile(), LN0->isNonTemporal(),
4410 LN0->getAlignment());
4411 CombineTo(N, ExtLoad);
4412 CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1));
4413 return SDValue(N, 0); // Return N so it doesn't get rechecked!
4415 // fold (sext_inreg (zextload x)) -> (sextload x) iff load has one use
4416 if (ISD::isZEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) &&
4418 EVT == cast<LoadSDNode>(N0)->getMemoryVT() &&
4419 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
4420 TLI.isLoadExtLegal(ISD::SEXTLOAD, EVT))) {
4421 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
4422 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N->getDebugLoc(),
4424 LN0->getBasePtr(), LN0->getPointerInfo(),
4426 LN0->isVolatile(), LN0->isNonTemporal(),
4427 LN0->getAlignment());
4428 CombineTo(N, ExtLoad);
4429 CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1));
4430 return SDValue(N, 0); // Return N so it doesn't get rechecked!
4435 SDValue DAGCombiner::visitTRUNCATE(SDNode *N) {
4436 SDValue N0 = N->getOperand(0);
4437 EVT VT = N->getValueType(0);
4440 if (N0.getValueType() == N->getValueType(0))
4442 // fold (truncate c1) -> c1
4443 if (isa<ConstantSDNode>(N0))
4444 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, N0);
4445 // fold (truncate (truncate x)) -> (truncate x)
4446 if (N0.getOpcode() == ISD::TRUNCATE)
4447 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, N0.getOperand(0));
4448 // fold (truncate (ext x)) -> (ext x) or (truncate x) or x
4449 if (N0.getOpcode() == ISD::ZERO_EXTEND ||
4450 N0.getOpcode() == ISD::SIGN_EXTEND ||
4451 N0.getOpcode() == ISD::ANY_EXTEND) {
4452 if (N0.getOperand(0).getValueType().bitsLT(VT))
4453 // if the source is smaller than the dest, we still need an extend
4454 return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT,
4456 else if (N0.getOperand(0).getValueType().bitsGT(VT))
4457 // if the source is larger than the dest, than we just need the truncate
4458 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, N0.getOperand(0));
4460 // if the source and dest are the same type, we can drop both the extend
4461 // and the truncate.
4462 return N0.getOperand(0);
4465 // See if we can simplify the input to this truncate through knowledge that
4466 // only the low bits are being used. For example "trunc (or (shl x, 8), y)"
4469 GetDemandedBits(N0, APInt::getLowBitsSet(N0.getValueSizeInBits(),
4470 VT.getSizeInBits()));
4471 if (Shorter.getNode())
4472 return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, Shorter);
4474 // fold (truncate (load x)) -> (smaller load x)
4475 // fold (truncate (srl (load x), c)) -> (smaller load (x+c/evtbits))
4476 if (!LegalTypes || TLI.isTypeDesirableForOp(N0.getOpcode(), VT)) {
4477 SDValue Reduced = ReduceLoadWidth(N);
4478 if (Reduced.getNode())
4482 // Simplify the operands using demanded-bits information.
4483 if (!VT.isVector() &&
4484 SimplifyDemandedBits(SDValue(N, 0)))
4485 return SDValue(N, 0);
4490 static SDNode *getBuildPairElt(SDNode *N, unsigned i) {
4491 SDValue Elt = N->getOperand(i);
4492 if (Elt.getOpcode() != ISD::MERGE_VALUES)
4493 return Elt.getNode();
4494 return Elt.getOperand(Elt.getResNo()).getNode();
4497 /// CombineConsecutiveLoads - build_pair (load, load) -> load
4498 /// if load locations are consecutive.
4499 SDValue DAGCombiner::CombineConsecutiveLoads(SDNode *N, EVT VT) {
4500 assert(N->getOpcode() == ISD::BUILD_PAIR);
4502 LoadSDNode *LD1 = dyn_cast<LoadSDNode>(getBuildPairElt(N, 0));
4503 LoadSDNode *LD2 = dyn_cast<LoadSDNode>(getBuildPairElt(N, 1));
4504 if (!LD1 || !LD2 || !ISD::isNON_EXTLoad(LD1) || !LD1->hasOneUse() ||
4505 LD1->getPointerInfo().getAddrSpace() !=
4506 LD2->getPointerInfo().getAddrSpace())
4508 EVT LD1VT = LD1->getValueType(0);
4510 if (ISD::isNON_EXTLoad(LD2) &&
4512 // If both are volatile this would reduce the number of volatile loads.
4513 // If one is volatile it might be ok, but play conservative and bail out.
4514 !LD1->isVolatile() &&
4515 !LD2->isVolatile() &&
4516 DAG.isConsecutiveLoad(LD2, LD1, LD1VT.getSizeInBits()/8, 1)) {
4517 unsigned Align = LD1->getAlignment();
4518 unsigned NewAlign = TLI.getTargetData()->
4519 getABITypeAlignment(VT.getTypeForEVT(*DAG.getContext()));
4521 if (NewAlign <= Align &&
4522 (!LegalOperations || TLI.isOperationLegal(ISD::LOAD, VT)))
4523 return DAG.getLoad(VT, N->getDebugLoc(), LD1->getChain(),
4524 LD1->getBasePtr(), LD1->getPointerInfo(),
4525 false, false, Align);
4531 SDValue DAGCombiner::visitBITCAST(SDNode *N) {
4532 SDValue N0 = N->getOperand(0);
4533 EVT VT = N->getValueType(0);
4535 // If the input is a BUILD_VECTOR with all constant elements, fold this now.
4536 // Only do this before legalize, since afterward the target may be depending
4537 // on the bitconvert.
4538 // First check to see if this is all constant.
4540 N0.getOpcode() == ISD::BUILD_VECTOR && N0.getNode()->hasOneUse() &&
4542 bool isSimple = true;
4543 for (unsigned i = 0, e = N0.getNumOperands(); i != e; ++i)
4544 if (N0.getOperand(i).getOpcode() != ISD::UNDEF &&
4545 N0.getOperand(i).getOpcode() != ISD::Constant &&
4546 N0.getOperand(i).getOpcode() != ISD::ConstantFP) {
4551 EVT DestEltVT = N->getValueType(0).getVectorElementType();
4552 assert(!DestEltVT.isVector() &&
4553 "Element type of vector ValueType must not be vector!");
4555 return ConstantFoldBITCASTofBUILD_VECTOR(N0.getNode(), DestEltVT);
4558 // If the input is a constant, let getNode fold it.
4559 if (isa<ConstantSDNode>(N0) || isa<ConstantFPSDNode>(N0)) {
4560 SDValue Res = DAG.getNode(ISD::BITCAST, N->getDebugLoc(), VT, N0);
4561 if (Res.getNode() != N) {
4562 if (!LegalOperations ||
4563 TLI.isOperationLegal(Res.getNode()->getOpcode(), VT))
4566 // Folding it resulted in an illegal node, and it's too late to
4567 // do that. Clean up the old node and forego the transformation.
4568 // Ideally this won't happen very often, because instcombine
4569 // and the earlier dagcombine runs (where illegal nodes are
4570 // permitted) should have folded most of them already.
4571 DAG.DeleteNode(Res.getNode());
4575 // (conv (conv x, t1), t2) -> (conv x, t2)
4576 if (N0.getOpcode() == ISD::BITCAST)
4577 return DAG.getNode(ISD::BITCAST, N->getDebugLoc(), VT,
4580 // fold (conv (load x)) -> (load (conv*)x)
4581 // If the resultant load doesn't need a higher alignment than the original!
4582 if (ISD::isNormalLoad(N0.getNode()) && N0.hasOneUse() &&
4583 // Do not change the width of a volatile load.
4584 !cast<LoadSDNode>(N0)->isVolatile() &&
4585 (!LegalOperations || TLI.isOperationLegal(ISD::LOAD, VT))) {
4586 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
4587 unsigned Align = TLI.getTargetData()->
4588 getABITypeAlignment(VT.getTypeForEVT(*DAG.getContext()));
4589 unsigned OrigAlign = LN0->getAlignment();
4591 if (Align <= OrigAlign) {
4592 SDValue Load = DAG.getLoad(VT, N->getDebugLoc(), LN0->getChain(),
4593 LN0->getBasePtr(), LN0->getPointerInfo(),
4594 LN0->isVolatile(), LN0->isNonTemporal(),
4597 CombineTo(N0.getNode(),
4598 DAG.getNode(ISD::BITCAST, N0.getDebugLoc(),
4599 N0.getValueType(), Load),
4605 // fold (bitconvert (fneg x)) -> (xor (bitconvert x), signbit)
4606 // fold (bitconvert (fabs x)) -> (and (bitconvert x), (not signbit))
4607 // This often reduces constant pool loads.
4608 if ((N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FABS) &&
4609 N0.getNode()->hasOneUse() && VT.isInteger() && !VT.isVector()) {
4610 SDValue NewConv = DAG.getNode(ISD::BITCAST, N0.getDebugLoc(), VT,
4612 AddToWorkList(NewConv.getNode());
4614 APInt SignBit = APInt::getSignBit(VT.getSizeInBits());
4615 if (N0.getOpcode() == ISD::FNEG)
4616 return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT,
4617 NewConv, DAG.getConstant(SignBit, VT));
4618 assert(N0.getOpcode() == ISD::FABS);
4619 return DAG.getNode(ISD::AND, N->getDebugLoc(), VT,
4620 NewConv, DAG.getConstant(~SignBit, VT));
4623 // fold (bitconvert (fcopysign cst, x)) ->
4624 // (or (and (bitconvert x), sign), (and cst, (not sign)))
4625 // Note that we don't handle (copysign x, cst) because this can always be
4626 // folded to an fneg or fabs.
4627 if (N0.getOpcode() == ISD::FCOPYSIGN && N0.getNode()->hasOneUse() &&
4628 isa<ConstantFPSDNode>(N0.getOperand(0)) &&
4629 VT.isInteger() && !VT.isVector()) {
4630 unsigned OrigXWidth = N0.getOperand(1).getValueType().getSizeInBits();
4631 EVT IntXVT = EVT::getIntegerVT(*DAG.getContext(), OrigXWidth);
4632 if (isTypeLegal(IntXVT)) {
4633 SDValue X = DAG.getNode(ISD::BITCAST, N0.getDebugLoc(),
4634 IntXVT, N0.getOperand(1));
4635 AddToWorkList(X.getNode());
4637 // If X has a different width than the result/lhs, sext it or truncate it.
4638 unsigned VTWidth = VT.getSizeInBits();
4639 if (OrigXWidth < VTWidth) {
4640 X = DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, X);
4641 AddToWorkList(X.getNode());
4642 } else if (OrigXWidth > VTWidth) {
4643 // To get the sign bit in the right place, we have to shift it right
4644 // before truncating.
4645 X = DAG.getNode(ISD::SRL, X.getDebugLoc(),
4646 X.getValueType(), X,
4647 DAG.getConstant(OrigXWidth-VTWidth, X.getValueType()));
4648 AddToWorkList(X.getNode());
4649 X = DAG.getNode(ISD::TRUNCATE, X.getDebugLoc(), VT, X);
4650 AddToWorkList(X.getNode());
4653 APInt SignBit = APInt::getSignBit(VT.getSizeInBits());
4654 X = DAG.getNode(ISD::AND, X.getDebugLoc(), VT,
4655 X, DAG.getConstant(SignBit, VT));
4656 AddToWorkList(X.getNode());
4658 SDValue Cst = DAG.getNode(ISD::BITCAST, N0.getDebugLoc(),
4659 VT, N0.getOperand(0));
4660 Cst = DAG.getNode(ISD::AND, Cst.getDebugLoc(), VT,
4661 Cst, DAG.getConstant(~SignBit, VT));
4662 AddToWorkList(Cst.getNode());
4664 return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, X, Cst);
4668 // bitconvert(build_pair(ld, ld)) -> ld iff load locations are consecutive.
4669 if (N0.getOpcode() == ISD::BUILD_PAIR) {
4670 SDValue CombineLD = CombineConsecutiveLoads(N0.getNode(), VT);
4671 if (CombineLD.getNode())
4678 SDValue DAGCombiner::visitBUILD_PAIR(SDNode *N) {
4679 EVT VT = N->getValueType(0);
4680 return CombineConsecutiveLoads(N, VT);
4683 /// ConstantFoldBITCASTofBUILD_VECTOR - We know that BV is a build_vector
4684 /// node with Constant, ConstantFP or Undef operands. DstEltVT indicates the
4685 /// destination element value type.
4686 SDValue DAGCombiner::
4687 ConstantFoldBITCASTofBUILD_VECTOR(SDNode *BV, EVT DstEltVT) {
4688 EVT SrcEltVT = BV->getValueType(0).getVectorElementType();
4690 // If this is already the right type, we're done.
4691 if (SrcEltVT == DstEltVT) return SDValue(BV, 0);
4693 unsigned SrcBitSize = SrcEltVT.getSizeInBits();
4694 unsigned DstBitSize = DstEltVT.getSizeInBits();
4696 // If this is a conversion of N elements of one type to N elements of another
4697 // type, convert each element. This handles FP<->INT cases.
4698 if (SrcBitSize == DstBitSize) {
4699 EVT VT = EVT::getVectorVT(*DAG.getContext(), DstEltVT,
4700 BV->getValueType(0).getVectorNumElements());
4702 // Due to the FP element handling below calling this routine recursively,
4703 // we can end up with a scalar-to-vector node here.
4704 if (BV->getOpcode() == ISD::SCALAR_TO_VECTOR)
4705 return DAG.getNode(ISD::SCALAR_TO_VECTOR, BV->getDebugLoc(), VT,
4706 DAG.getNode(ISD::BITCAST, BV->getDebugLoc(),
4707 DstEltVT, BV->getOperand(0)));
4709 SmallVector<SDValue, 8> Ops;
4710 for (unsigned i = 0, e = BV->getNumOperands(); i != e; ++i) {
4711 SDValue Op = BV->getOperand(i);
4712 // If the vector element type is not legal, the BUILD_VECTOR operands
4713 // are promoted and implicitly truncated. Make that explicit here.
4714 if (Op.getValueType() != SrcEltVT)
4715 Op = DAG.getNode(ISD::TRUNCATE, BV->getDebugLoc(), SrcEltVT, Op);
4716 Ops.push_back(DAG.getNode(ISD::BITCAST, BV->getDebugLoc(),
4718 AddToWorkList(Ops.back().getNode());
4720 return DAG.getNode(ISD::BUILD_VECTOR, BV->getDebugLoc(), VT,
4721 &Ops[0], Ops.size());
4724 // Otherwise, we're growing or shrinking the elements. To avoid having to
4725 // handle annoying details of growing/shrinking FP values, we convert them to
4727 if (SrcEltVT.isFloatingPoint()) {
4728 // Convert the input float vector to a int vector where the elements are the
4730 assert((SrcEltVT == MVT::f32 || SrcEltVT == MVT::f64) && "Unknown FP VT!");
4731 EVT IntVT = EVT::getIntegerVT(*DAG.getContext(), SrcEltVT.getSizeInBits());
4732 BV = ConstantFoldBITCASTofBUILD_VECTOR(BV, IntVT).getNode();
4736 // Now we know the input is an integer vector. If the output is a FP type,
4737 // convert to integer first, then to FP of the right size.
4738 if (DstEltVT.isFloatingPoint()) {
4739 assert((DstEltVT == MVT::f32 || DstEltVT == MVT::f64) && "Unknown FP VT!");
4740 EVT TmpVT = EVT::getIntegerVT(*DAG.getContext(), DstEltVT.getSizeInBits());
4741 SDNode *Tmp = ConstantFoldBITCASTofBUILD_VECTOR(BV, TmpVT).getNode();
4743 // Next, convert to FP elements of the same size.
4744 return ConstantFoldBITCASTofBUILD_VECTOR(Tmp, DstEltVT);
4747 // Okay, we know the src/dst types are both integers of differing types.
4748 // Handling growing first.
4749 assert(SrcEltVT.isInteger() && DstEltVT.isInteger());
4750 if (SrcBitSize < DstBitSize) {
4751 unsigned NumInputsPerOutput = DstBitSize/SrcBitSize;
4753 SmallVector<SDValue, 8> Ops;
4754 for (unsigned i = 0, e = BV->getNumOperands(); i != e;
4755 i += NumInputsPerOutput) {
4756 bool isLE = TLI.isLittleEndian();
4757 APInt NewBits = APInt(DstBitSize, 0);
4758 bool EltIsUndef = true;
4759 for (unsigned j = 0; j != NumInputsPerOutput; ++j) {
4760 // Shift the previously computed bits over.
4761 NewBits <<= SrcBitSize;
4762 SDValue Op = BV->getOperand(i+ (isLE ? (NumInputsPerOutput-j-1) : j));
4763 if (Op.getOpcode() == ISD::UNDEF) continue;
4766 NewBits |= cast<ConstantSDNode>(Op)->getAPIntValue().
4767 zextOrTrunc(SrcBitSize).zext(DstBitSize);
4771 Ops.push_back(DAG.getUNDEF(DstEltVT));
4773 Ops.push_back(DAG.getConstant(NewBits, DstEltVT));
4776 EVT VT = EVT::getVectorVT(*DAG.getContext(), DstEltVT, Ops.size());
4777 return DAG.getNode(ISD::BUILD_VECTOR, BV->getDebugLoc(), VT,
4778 &Ops[0], Ops.size());
4781 // Finally, this must be the case where we are shrinking elements: each input
4782 // turns into multiple outputs.
4783 bool isS2V = ISD::isScalarToVector(BV);
4784 unsigned NumOutputsPerInput = SrcBitSize/DstBitSize;
4785 EVT VT = EVT::getVectorVT(*DAG.getContext(), DstEltVT,
4786 NumOutputsPerInput*BV->getNumOperands());
4787 SmallVector<SDValue, 8> Ops;
4789 for (unsigned i = 0, e = BV->getNumOperands(); i != e; ++i) {
4790 if (BV->getOperand(i).getOpcode() == ISD::UNDEF) {
4791 for (unsigned j = 0; j != NumOutputsPerInput; ++j)
4792 Ops.push_back(DAG.getUNDEF(DstEltVT));
4796 APInt OpVal = cast<ConstantSDNode>(BV->getOperand(i))->
4797 getAPIntValue().zextOrTrunc(SrcBitSize);
4799 for (unsigned j = 0; j != NumOutputsPerInput; ++j) {
4800 APInt ThisVal = OpVal.trunc(DstBitSize);
4801 Ops.push_back(DAG.getConstant(ThisVal, DstEltVT));
4802 if (isS2V && i == 0 && j == 0 && ThisVal.zext(SrcBitSize) == OpVal)
4803 // Simply turn this into a SCALAR_TO_VECTOR of the new type.
4804 return DAG.getNode(ISD::SCALAR_TO_VECTOR, BV->getDebugLoc(), VT,
4806 OpVal = OpVal.lshr(DstBitSize);
4809 // For big endian targets, swap the order of the pieces of each element.
4810 if (TLI.isBigEndian())
4811 std::reverse(Ops.end()-NumOutputsPerInput, Ops.end());
4814 return DAG.getNode(ISD::BUILD_VECTOR, BV->getDebugLoc(), VT,
4815 &Ops[0], Ops.size());
4818 SDValue DAGCombiner::visitFADD(SDNode *N) {
4819 SDValue N0 = N->getOperand(0);
4820 SDValue N1 = N->getOperand(1);
4821 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
4822 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
4823 EVT VT = N->getValueType(0);
4826 if (VT.isVector()) {
4827 SDValue FoldedVOp = SimplifyVBinOp(N);
4828 if (FoldedVOp.getNode()) return FoldedVOp;
4831 // fold (fadd c1, c2) -> (fadd c1, c2)
4832 if (N0CFP && N1CFP && VT != MVT::ppcf128)
4833 return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0, N1);
4834 // canonicalize constant to RHS
4835 if (N0CFP && !N1CFP)
4836 return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N1, N0);
4837 // fold (fadd A, 0) -> A
4838 if (UnsafeFPMath && N1CFP && N1CFP->getValueAPF().isZero())
4840 // fold (fadd A, (fneg B)) -> (fsub A, B)
4841 if (isNegatibleForFree(N1, LegalOperations) == 2)
4842 return DAG.getNode(ISD::FSUB, N->getDebugLoc(), VT, N0,
4843 GetNegatedExpression(N1, DAG, LegalOperations));
4844 // fold (fadd (fneg A), B) -> (fsub B, A)
4845 if (isNegatibleForFree(N0, LegalOperations) == 2)
4846 return DAG.getNode(ISD::FSUB, N->getDebugLoc(), VT, N1,
4847 GetNegatedExpression(N0, DAG, LegalOperations));
4849 // If allowed, fold (fadd (fadd x, c1), c2) -> (fadd x, (fadd c1, c2))
4850 if (UnsafeFPMath && N1CFP && N0.getOpcode() == ISD::FADD &&
4851 N0.getNode()->hasOneUse() && isa<ConstantFPSDNode>(N0.getOperand(1)))
4852 return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0.getOperand(0),
4853 DAG.getNode(ISD::FADD, N->getDebugLoc(), VT,
4854 N0.getOperand(1), N1));
4859 SDValue DAGCombiner::visitFSUB(SDNode *N) {
4860 SDValue N0 = N->getOperand(0);
4861 SDValue N1 = N->getOperand(1);
4862 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
4863 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
4864 EVT VT = N->getValueType(0);
4867 if (VT.isVector()) {
4868 SDValue FoldedVOp = SimplifyVBinOp(N);
4869 if (FoldedVOp.getNode()) return FoldedVOp;
4872 // fold (fsub c1, c2) -> c1-c2
4873 if (N0CFP && N1CFP && VT != MVT::ppcf128)
4874 return DAG.getNode(ISD::FSUB, N->getDebugLoc(), VT, N0, N1);
4875 // fold (fsub A, 0) -> A
4876 if (UnsafeFPMath && N1CFP && N1CFP->getValueAPF().isZero())
4878 // fold (fsub 0, B) -> -B
4879 if (UnsafeFPMath && N0CFP && N0CFP->getValueAPF().isZero()) {
4880 if (isNegatibleForFree(N1, LegalOperations))
4881 return GetNegatedExpression(N1, DAG, LegalOperations);
4882 if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT))
4883 return DAG.getNode(ISD::FNEG, N->getDebugLoc(), VT, N1);
4885 // fold (fsub A, (fneg B)) -> (fadd A, B)
4886 if (isNegatibleForFree(N1, LegalOperations))
4887 return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0,
4888 GetNegatedExpression(N1, DAG, LegalOperations));
4893 SDValue DAGCombiner::visitFMUL(SDNode *N) {
4894 SDValue N0 = N->getOperand(0);
4895 SDValue N1 = N->getOperand(1);
4896 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
4897 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
4898 EVT VT = N->getValueType(0);
4901 if (VT.isVector()) {
4902 SDValue FoldedVOp = SimplifyVBinOp(N);
4903 if (FoldedVOp.getNode()) return FoldedVOp;
4906 // fold (fmul c1, c2) -> c1*c2
4907 if (N0CFP && N1CFP && VT != MVT::ppcf128)
4908 return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, N0, N1);
4909 // canonicalize constant to RHS
4910 if (N0CFP && !N1CFP)
4911 return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, N1, N0);
4912 // fold (fmul A, 0) -> 0
4913 if (UnsafeFPMath && N1CFP && N1CFP->getValueAPF().isZero())
4915 // fold (fmul A, 0) -> 0, vector edition.
4916 if (UnsafeFPMath && ISD::isBuildVectorAllZeros(N1.getNode()))
4918 // fold (fmul X, 2.0) -> (fadd X, X)
4919 if (N1CFP && N1CFP->isExactlyValue(+2.0))
4920 return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0, N0);
4921 // fold (fmul X, -1.0) -> (fneg X)
4922 if (N1CFP && N1CFP->isExactlyValue(-1.0))
4923 if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT))
4924 return DAG.getNode(ISD::FNEG, N->getDebugLoc(), VT, N0);
4926 // fold (fmul (fneg X), (fneg Y)) -> (fmul X, Y)
4927 if (char LHSNeg = isNegatibleForFree(N0, LegalOperations)) {
4928 if (char RHSNeg = isNegatibleForFree(N1, LegalOperations)) {
4929 // Both can be negated for free, check to see if at least one is cheaper
4931 if (LHSNeg == 2 || RHSNeg == 2)
4932 return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT,
4933 GetNegatedExpression(N0, DAG, LegalOperations),
4934 GetNegatedExpression(N1, DAG, LegalOperations));
4938 // If allowed, fold (fmul (fmul x, c1), c2) -> (fmul x, (fmul c1, c2))
4939 if (UnsafeFPMath && N1CFP && N0.getOpcode() == ISD::FMUL &&
4940 N0.getNode()->hasOneUse() && isa<ConstantFPSDNode>(N0.getOperand(1)))
4941 return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, N0.getOperand(0),
4942 DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT,
4943 N0.getOperand(1), N1));
4948 SDValue DAGCombiner::visitFDIV(SDNode *N) {
4949 SDValue N0 = N->getOperand(0);
4950 SDValue N1 = N->getOperand(1);
4951 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
4952 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
4953 EVT VT = N->getValueType(0);
4956 if (VT.isVector()) {
4957 SDValue FoldedVOp = SimplifyVBinOp(N);
4958 if (FoldedVOp.getNode()) return FoldedVOp;
4961 // fold (fdiv c1, c2) -> c1/c2
4962 if (N0CFP && N1CFP && VT != MVT::ppcf128)
4963 return DAG.getNode(ISD::FDIV, N->getDebugLoc(), VT, N0, N1);
4966 // (fdiv (fneg X), (fneg Y)) -> (fdiv X, Y)
4967 if (char LHSNeg = isNegatibleForFree(N0, LegalOperations)) {
4968 if (char RHSNeg = isNegatibleForFree(N1, LegalOperations)) {
4969 // Both can be negated for free, check to see if at least one is cheaper
4971 if (LHSNeg == 2 || RHSNeg == 2)
4972 return DAG.getNode(ISD::FDIV, N->getDebugLoc(), VT,
4973 GetNegatedExpression(N0, DAG, LegalOperations),
4974 GetNegatedExpression(N1, DAG, LegalOperations));
4981 SDValue DAGCombiner::visitFREM(SDNode *N) {
4982 SDValue N0 = N->getOperand(0);
4983 SDValue N1 = N->getOperand(1);
4984 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
4985 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
4986 EVT VT = N->getValueType(0);
4988 // fold (frem c1, c2) -> fmod(c1,c2)
4989 if (N0CFP && N1CFP && VT != MVT::ppcf128)
4990 return DAG.getNode(ISD::FREM, N->getDebugLoc(), VT, N0, N1);
4995 SDValue DAGCombiner::visitFCOPYSIGN(SDNode *N) {
4996 SDValue N0 = N->getOperand(0);
4997 SDValue N1 = N->getOperand(1);
4998 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
4999 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
5000 EVT VT = N->getValueType(0);
5002 if (N0CFP && N1CFP && VT != MVT::ppcf128) // Constant fold
5003 return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT, N0, N1);
5006 const APFloat& V = N1CFP->getValueAPF();
5007 // copysign(x, c1) -> fabs(x) iff ispos(c1)
5008 // copysign(x, c1) -> fneg(fabs(x)) iff isneg(c1)
5009 if (!V.isNegative()) {
5010 if (!LegalOperations || TLI.isOperationLegal(ISD::FABS, VT))
5011 return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0);
5013 if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT))
5014 return DAG.getNode(ISD::FNEG, N->getDebugLoc(), VT,
5015 DAG.getNode(ISD::FABS, N0.getDebugLoc(), VT, N0));
5019 // copysign(fabs(x), y) -> copysign(x, y)
5020 // copysign(fneg(x), y) -> copysign(x, y)
5021 // copysign(copysign(x,z), y) -> copysign(x, y)
5022 if (N0.getOpcode() == ISD::FABS || N0.getOpcode() == ISD::FNEG ||
5023 N0.getOpcode() == ISD::FCOPYSIGN)
5024 return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT,
5025 N0.getOperand(0), N1);
5027 // copysign(x, abs(y)) -> abs(x)
5028 if (N1.getOpcode() == ISD::FABS)
5029 return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0);
5031 // copysign(x, copysign(y,z)) -> copysign(x, z)
5032 if (N1.getOpcode() == ISD::FCOPYSIGN)
5033 return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT,
5034 N0, N1.getOperand(1));
5036 // copysign(x, fp_extend(y)) -> copysign(x, y)
5037 // copysign(x, fp_round(y)) -> copysign(x, y)
5038 if (N1.getOpcode() == ISD::FP_EXTEND || N1.getOpcode() == ISD::FP_ROUND)
5039 return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT,
5040 N0, N1.getOperand(0));
5045 SDValue DAGCombiner::visitSINT_TO_FP(SDNode *N) {
5046 SDValue N0 = N->getOperand(0);
5047 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
5048 EVT VT = N->getValueType(0);
5049 EVT OpVT = N0.getValueType();
5051 // fold (sint_to_fp c1) -> c1fp
5052 if (N0C && OpVT != MVT::ppcf128)
5053 return DAG.getNode(ISD::SINT_TO_FP, N->getDebugLoc(), VT, N0);
5055 // If the input is a legal type, and SINT_TO_FP is not legal on this target,
5056 // but UINT_TO_FP is legal on this target, try to convert.
5057 if (!TLI.isOperationLegalOrCustom(ISD::SINT_TO_FP, OpVT) &&
5058 TLI.isOperationLegalOrCustom(ISD::UINT_TO_FP, OpVT)) {
5059 // If the sign bit is known to be zero, we can change this to UINT_TO_FP.
5060 if (DAG.SignBitIsZero(N0))
5061 return DAG.getNode(ISD::UINT_TO_FP, N->getDebugLoc(), VT, N0);
5067 SDValue DAGCombiner::visitUINT_TO_FP(SDNode *N) {
5068 SDValue N0 = N->getOperand(0);
5069 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
5070 EVT VT = N->getValueType(0);
5071 EVT OpVT = N0.getValueType();
5073 // fold (uint_to_fp c1) -> c1fp
5074 if (N0C && OpVT != MVT::ppcf128)
5075 return DAG.getNode(ISD::UINT_TO_FP, N->getDebugLoc(), VT, N0);
5077 // If the input is a legal type, and UINT_TO_FP is not legal on this target,
5078 // but SINT_TO_FP is legal on this target, try to convert.
5079 if (!TLI.isOperationLegalOrCustom(ISD::UINT_TO_FP, OpVT) &&
5080 TLI.isOperationLegalOrCustom(ISD::SINT_TO_FP, OpVT)) {
5081 // If the sign bit is known to be zero, we can change this to SINT_TO_FP.
5082 if (DAG.SignBitIsZero(N0))
5083 return DAG.getNode(ISD::SINT_TO_FP, N->getDebugLoc(), VT, N0);
5089 SDValue DAGCombiner::visitFP_TO_SINT(SDNode *N) {
5090 SDValue N0 = N->getOperand(0);
5091 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
5092 EVT VT = N->getValueType(0);
5094 // fold (fp_to_sint c1fp) -> c1
5096 return DAG.getNode(ISD::FP_TO_SINT, N->getDebugLoc(), VT, N0);
5101 SDValue DAGCombiner::visitFP_TO_UINT(SDNode *N) {
5102 SDValue N0 = N->getOperand(0);
5103 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
5104 EVT VT = N->getValueType(0);
5106 // fold (fp_to_uint c1fp) -> c1
5107 if (N0CFP && VT != MVT::ppcf128)
5108 return DAG.getNode(ISD::FP_TO_UINT, N->getDebugLoc(), VT, N0);
5113 SDValue DAGCombiner::visitFP_ROUND(SDNode *N) {
5114 SDValue N0 = N->getOperand(0);
5115 SDValue N1 = N->getOperand(1);
5116 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
5117 EVT VT = N->getValueType(0);
5119 // fold (fp_round c1fp) -> c1fp
5120 if (N0CFP && N0.getValueType() != MVT::ppcf128)
5121 return DAG.getNode(ISD::FP_ROUND, N->getDebugLoc(), VT, N0, N1);
5123 // fold (fp_round (fp_extend x)) -> x
5124 if (N0.getOpcode() == ISD::FP_EXTEND && VT == N0.getOperand(0).getValueType())
5125 return N0.getOperand(0);
5127 // fold (fp_round (fp_round x)) -> (fp_round x)
5128 if (N0.getOpcode() == ISD::FP_ROUND) {
5129 // This is a value preserving truncation if both round's are.
5130 bool IsTrunc = N->getConstantOperandVal(1) == 1 &&
5131 N0.getNode()->getConstantOperandVal(1) == 1;
5132 return DAG.getNode(ISD::FP_ROUND, N->getDebugLoc(), VT, N0.getOperand(0),
5133 DAG.getIntPtrConstant(IsTrunc));
5136 // fold (fp_round (copysign X, Y)) -> (copysign (fp_round X), Y)
5137 if (N0.getOpcode() == ISD::FCOPYSIGN && N0.getNode()->hasOneUse()) {
5138 SDValue Tmp = DAG.getNode(ISD::FP_ROUND, N0.getDebugLoc(), VT,
5139 N0.getOperand(0), N1);
5140 AddToWorkList(Tmp.getNode());
5141 return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT,
5142 Tmp, N0.getOperand(1));
5148 SDValue DAGCombiner::visitFP_ROUND_INREG(SDNode *N) {
5149 SDValue N0 = N->getOperand(0);
5150 EVT VT = N->getValueType(0);
5151 EVT EVT = cast<VTSDNode>(N->getOperand(1))->getVT();
5152 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
5154 // fold (fp_round_inreg c1fp) -> c1fp
5155 if (N0CFP && isTypeLegal(EVT)) {
5156 SDValue Round = DAG.getConstantFP(*N0CFP->getConstantFPValue(), EVT);
5157 return DAG.getNode(ISD::FP_EXTEND, N->getDebugLoc(), VT, Round);
5163 SDValue DAGCombiner::visitFP_EXTEND(SDNode *N) {
5164 SDValue N0 = N->getOperand(0);
5165 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
5166 EVT VT = N->getValueType(0);
5168 // If this is fp_round(fpextend), don't fold it, allow ourselves to be folded.
5169 if (N->hasOneUse() &&
5170 N->use_begin()->getOpcode() == ISD::FP_ROUND)
5173 // fold (fp_extend c1fp) -> c1fp
5174 if (N0CFP && VT != MVT::ppcf128)
5175 return DAG.getNode(ISD::FP_EXTEND, N->getDebugLoc(), VT, N0);
5177 // Turn fp_extend(fp_round(X, 1)) -> x since the fp_round doesn't affect the
5179 if (N0.getOpcode() == ISD::FP_ROUND
5180 && N0.getNode()->getConstantOperandVal(1) == 1) {
5181 SDValue In = N0.getOperand(0);
5182 if (In.getValueType() == VT) return In;
5183 if (VT.bitsLT(In.getValueType()))
5184 return DAG.getNode(ISD::FP_ROUND, N->getDebugLoc(), VT,
5185 In, N0.getOperand(1));
5186 return DAG.getNode(ISD::FP_EXTEND, N->getDebugLoc(), VT, In);
5189 // fold (fpext (load x)) -> (fpext (fptrunc (extload x)))
5190 if (ISD::isNON_EXTLoad(N0.getNode()) && N0.hasOneUse() &&
5191 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
5192 TLI.isLoadExtLegal(ISD::EXTLOAD, N0.getValueType()))) {
5193 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
5194 SDValue ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, VT, N->getDebugLoc(),
5196 LN0->getBasePtr(), LN0->getPointerInfo(),
5198 LN0->isVolatile(), LN0->isNonTemporal(),
5199 LN0->getAlignment());
5200 CombineTo(N, ExtLoad);
5201 CombineTo(N0.getNode(),
5202 DAG.getNode(ISD::FP_ROUND, N0.getDebugLoc(),
5203 N0.getValueType(), ExtLoad, DAG.getIntPtrConstant(1)),
5204 ExtLoad.getValue(1));
5205 return SDValue(N, 0); // Return N so it doesn't get rechecked!
5211 SDValue DAGCombiner::visitFNEG(SDNode *N) {
5212 SDValue N0 = N->getOperand(0);
5213 EVT VT = N->getValueType(0);
5215 if (isNegatibleForFree(N0, LegalOperations))
5216 return GetNegatedExpression(N0, DAG, LegalOperations);
5218 // Transform fneg(bitconvert(x)) -> bitconvert(x^sign) to avoid loading
5219 // constant pool values.
5220 if (N0.getOpcode() == ISD::BITCAST &&
5222 N0.getNode()->hasOneUse() &&
5223 N0.getOperand(0).getValueType().isInteger()) {
5224 SDValue Int = N0.getOperand(0);
5225 EVT IntVT = Int.getValueType();
5226 if (IntVT.isInteger() && !IntVT.isVector()) {
5227 Int = DAG.getNode(ISD::XOR, N0.getDebugLoc(), IntVT, Int,
5228 DAG.getConstant(APInt::getSignBit(IntVT.getSizeInBits()), IntVT));
5229 AddToWorkList(Int.getNode());
5230 return DAG.getNode(ISD::BITCAST, N->getDebugLoc(),
5238 SDValue DAGCombiner::visitFABS(SDNode *N) {
5239 SDValue N0 = N->getOperand(0);
5240 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
5241 EVT VT = N->getValueType(0);
5243 // fold (fabs c1) -> fabs(c1)
5244 if (N0CFP && VT != MVT::ppcf128)
5245 return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0);
5246 // fold (fabs (fabs x)) -> (fabs x)
5247 if (N0.getOpcode() == ISD::FABS)
5248 return N->getOperand(0);
5249 // fold (fabs (fneg x)) -> (fabs x)
5250 // fold (fabs (fcopysign x, y)) -> (fabs x)
5251 if (N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FCOPYSIGN)
5252 return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0.getOperand(0));
5254 // Transform fabs(bitconvert(x)) -> bitconvert(x&~sign) to avoid loading
5255 // constant pool values.
5256 if (N0.getOpcode() == ISD::BITCAST && N0.getNode()->hasOneUse() &&
5257 N0.getOperand(0).getValueType().isInteger() &&
5258 !N0.getOperand(0).getValueType().isVector()) {
5259 SDValue Int = N0.getOperand(0);
5260 EVT IntVT = Int.getValueType();
5261 if (IntVT.isInteger() && !IntVT.isVector()) {
5262 Int = DAG.getNode(ISD::AND, N0.getDebugLoc(), IntVT, Int,
5263 DAG.getConstant(~APInt::getSignBit(IntVT.getSizeInBits()), IntVT));
5264 AddToWorkList(Int.getNode());
5265 return DAG.getNode(ISD::BITCAST, N->getDebugLoc(),
5266 N->getValueType(0), Int);
5273 SDValue DAGCombiner::visitBRCOND(SDNode *N) {
5274 SDValue Chain = N->getOperand(0);
5275 SDValue N1 = N->getOperand(1);
5276 SDValue N2 = N->getOperand(2);
5278 // If N is a constant we could fold this into a fallthrough or unconditional
5279 // branch. However that doesn't happen very often in normal code, because
5280 // Instcombine/SimplifyCFG should have handled the available opportunities.
5281 // If we did this folding here, it would be necessary to update the
5282 // MachineBasicBlock CFG, which is awkward.
5284 // fold a brcond with a setcc condition into a BR_CC node if BR_CC is legal
5286 if (N1.getOpcode() == ISD::SETCC &&
5287 TLI.isOperationLegalOrCustom(ISD::BR_CC, MVT::Other)) {
5288 return DAG.getNode(ISD::BR_CC, N->getDebugLoc(), MVT::Other,
5289 Chain, N1.getOperand(2),
5290 N1.getOperand(0), N1.getOperand(1), N2);
5293 if ((N1.hasOneUse() && N1.getOpcode() == ISD::SRL) ||
5294 ((N1.getOpcode() == ISD::TRUNCATE && N1.hasOneUse()) &&
5295 (N1.getOperand(0).hasOneUse() &&
5296 N1.getOperand(0).getOpcode() == ISD::SRL))) {
5298 if (N1.getOpcode() == ISD::TRUNCATE) {
5299 // Look pass the truncate.
5300 Trunc = N1.getNode();
5301 N1 = N1.getOperand(0);
5304 // Match this pattern so that we can generate simpler code:
5307 // %b = and i32 %a, 2
5308 // %c = srl i32 %b, 1
5309 // brcond i32 %c ...
5314 // %b = and i32 %a, 2
5315 // %c = setcc eq %b, 0
5318 // This applies only when the AND constant value has one bit set and the
5319 // SRL constant is equal to the log2 of the AND constant. The back-end is
5320 // smart enough to convert the result into a TEST/JMP sequence.
5321 SDValue Op0 = N1.getOperand(0);
5322 SDValue Op1 = N1.getOperand(1);
5324 if (Op0.getOpcode() == ISD::AND &&
5325 Op1.getOpcode() == ISD::Constant) {
5326 SDValue AndOp1 = Op0.getOperand(1);
5328 if (AndOp1.getOpcode() == ISD::Constant) {
5329 const APInt &AndConst = cast<ConstantSDNode>(AndOp1)->getAPIntValue();
5331 if (AndConst.isPowerOf2() &&
5332 cast<ConstantSDNode>(Op1)->getAPIntValue()==AndConst.logBase2()) {
5334 DAG.getSetCC(N->getDebugLoc(),
5335 TLI.getSetCCResultType(Op0.getValueType()),
5336 Op0, DAG.getConstant(0, Op0.getValueType()),
5339 SDValue NewBRCond = DAG.getNode(ISD::BRCOND, N->getDebugLoc(),
5340 MVT::Other, Chain, SetCC, N2);
5341 // Don't add the new BRCond into the worklist or else SimplifySelectCC
5342 // will convert it back to (X & C1) >> C2.
5343 CombineTo(N, NewBRCond, false);
5344 // Truncate is dead.
5346 removeFromWorkList(Trunc);
5347 DAG.DeleteNode(Trunc);
5349 // Replace the uses of SRL with SETCC
5350 WorkListRemover DeadNodes(*this);
5351 DAG.ReplaceAllUsesOfValueWith(N1, SetCC, &DeadNodes);
5352 removeFromWorkList(N1.getNode());
5353 DAG.DeleteNode(N1.getNode());
5354 return SDValue(N, 0); // Return N so it doesn't get rechecked!
5360 // Restore N1 if the above transformation doesn't match.
5361 N1 = N->getOperand(1);
5364 // Transform br(xor(x, y)) -> br(x != y)
5365 // Transform br(xor(xor(x,y), 1)) -> br (x == y)
5366 if (N1.hasOneUse() && N1.getOpcode() == ISD::XOR) {
5367 SDNode *TheXor = N1.getNode();
5368 SDValue Op0 = TheXor->getOperand(0);
5369 SDValue Op1 = TheXor->getOperand(1);
5370 if (Op0.getOpcode() == Op1.getOpcode()) {
5371 // Avoid missing important xor optimizations.
5372 SDValue Tmp = visitXOR(TheXor);
5373 if (Tmp.getNode() && Tmp.getNode() != TheXor) {
5374 DEBUG(dbgs() << "\nReplacing.8 ";
5376 dbgs() << "\nWith: ";
5377 Tmp.getNode()->dump(&DAG);
5379 WorkListRemover DeadNodes(*this);
5380 DAG.ReplaceAllUsesOfValueWith(N1, Tmp, &DeadNodes);
5381 removeFromWorkList(TheXor);
5382 DAG.DeleteNode(TheXor);
5383 return DAG.getNode(ISD::BRCOND, N->getDebugLoc(),
5384 MVT::Other, Chain, Tmp, N2);
5388 if (Op0.getOpcode() != ISD::SETCC && Op1.getOpcode() != ISD::SETCC) {
5390 if (ConstantSDNode *RHSCI = dyn_cast<ConstantSDNode>(Op0))
5391 if (RHSCI->getAPIntValue() == 1 && Op0.hasOneUse() &&
5392 Op0.getOpcode() == ISD::XOR) {
5393 TheXor = Op0.getNode();
5397 EVT SetCCVT = N1.getValueType();
5399 SetCCVT = TLI.getSetCCResultType(SetCCVT);
5400 SDValue SetCC = DAG.getSetCC(TheXor->getDebugLoc(),
5403 Equal ? ISD::SETEQ : ISD::SETNE);
5404 // Replace the uses of XOR with SETCC
5405 WorkListRemover DeadNodes(*this);
5406 DAG.ReplaceAllUsesOfValueWith(N1, SetCC, &DeadNodes);
5407 removeFromWorkList(N1.getNode());
5408 DAG.DeleteNode(N1.getNode());
5409 return DAG.getNode(ISD::BRCOND, N->getDebugLoc(),
5410 MVT::Other, Chain, SetCC, N2);
5417 // Operand List for BR_CC: Chain, CondCC, CondLHS, CondRHS, DestBB.
5419 SDValue DAGCombiner::visitBR_CC(SDNode *N) {
5420 CondCodeSDNode *CC = cast<CondCodeSDNode>(N->getOperand(1));
5421 SDValue CondLHS = N->getOperand(2), CondRHS = N->getOperand(3);
5423 // If N is a constant we could fold this into a fallthrough or unconditional
5424 // branch. However that doesn't happen very often in normal code, because
5425 // Instcombine/SimplifyCFG should have handled the available opportunities.
5426 // If we did this folding here, it would be necessary to update the
5427 // MachineBasicBlock CFG, which is awkward.
5429 // Use SimplifySetCC to simplify SETCC's.
5430 SDValue Simp = SimplifySetCC(TLI.getSetCCResultType(CondLHS.getValueType()),
5431 CondLHS, CondRHS, CC->get(), N->getDebugLoc(),
5433 if (Simp.getNode()) AddToWorkList(Simp.getNode());
5435 // fold to a simpler setcc
5436 if (Simp.getNode() && Simp.getOpcode() == ISD::SETCC)
5437 return DAG.getNode(ISD::BR_CC, N->getDebugLoc(), MVT::Other,
5438 N->getOperand(0), Simp.getOperand(2),
5439 Simp.getOperand(0), Simp.getOperand(1),
5445 /// CombineToPreIndexedLoadStore - Try turning a load / store into a
5446 /// pre-indexed load / store when the base pointer is an add or subtract
5447 /// and it has other uses besides the load / store. After the
5448 /// transformation, the new indexed load / store has effectively folded
5449 /// the add / subtract in and all of its other uses are redirected to the
5450 /// new load / store.
5451 bool DAGCombiner::CombineToPreIndexedLoadStore(SDNode *N) {
5452 if (!LegalOperations)
5458 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) {
5459 if (LD->isIndexed())
5461 VT = LD->getMemoryVT();
5462 if (!TLI.isIndexedLoadLegal(ISD::PRE_INC, VT) &&
5463 !TLI.isIndexedLoadLegal(ISD::PRE_DEC, VT))
5465 Ptr = LD->getBasePtr();
5466 } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) {
5467 if (ST->isIndexed())
5469 VT = ST->getMemoryVT();
5470 if (!TLI.isIndexedStoreLegal(ISD::PRE_INC, VT) &&
5471 !TLI.isIndexedStoreLegal(ISD::PRE_DEC, VT))
5473 Ptr = ST->getBasePtr();
5479 // If the pointer is not an add/sub, or if it doesn't have multiple uses, bail
5480 // out. There is no reason to make this a preinc/predec.
5481 if ((Ptr.getOpcode() != ISD::ADD && Ptr.getOpcode() != ISD::SUB) ||
5482 Ptr.getNode()->hasOneUse())
5485 // Ask the target to do addressing mode selection.
5488 ISD::MemIndexedMode AM = ISD::UNINDEXED;
5489 if (!TLI.getPreIndexedAddressParts(N, BasePtr, Offset, AM, DAG))
5491 // Don't create a indexed load / store with zero offset.
5492 if (isa<ConstantSDNode>(Offset) &&
5493 cast<ConstantSDNode>(Offset)->isNullValue())
5496 // Try turning it into a pre-indexed load / store except when:
5497 // 1) The new base ptr is a frame index.
5498 // 2) If N is a store and the new base ptr is either the same as or is a
5499 // predecessor of the value being stored.
5500 // 3) Another use of old base ptr is a predecessor of N. If ptr is folded
5501 // that would create a cycle.
5502 // 4) All uses are load / store ops that use it as old base ptr.
5504 // Check #1. Preinc'ing a frame index would require copying the stack pointer
5505 // (plus the implicit offset) to a register to preinc anyway.
5506 if (isa<FrameIndexSDNode>(BasePtr) || isa<RegisterSDNode>(BasePtr))
5511 SDValue Val = cast<StoreSDNode>(N)->getValue();
5512 if (Val == BasePtr || BasePtr.getNode()->isPredecessorOf(Val.getNode()))
5516 // Now check for #3 and #4.
5517 bool RealUse = false;
5518 for (SDNode::use_iterator I = Ptr.getNode()->use_begin(),
5519 E = Ptr.getNode()->use_end(); I != E; ++I) {
5523 if (Use->isPredecessorOf(N))
5526 if (!((Use->getOpcode() == ISD::LOAD &&
5527 cast<LoadSDNode>(Use)->getBasePtr() == Ptr) ||
5528 (Use->getOpcode() == ISD::STORE &&
5529 cast<StoreSDNode>(Use)->getBasePtr() == Ptr)))
5538 Result = DAG.getIndexedLoad(SDValue(N,0), N->getDebugLoc(),
5539 BasePtr, Offset, AM);
5541 Result = DAG.getIndexedStore(SDValue(N,0), N->getDebugLoc(),
5542 BasePtr, Offset, AM);
5545 DEBUG(dbgs() << "\nReplacing.4 ";
5547 dbgs() << "\nWith: ";
5548 Result.getNode()->dump(&DAG);
5550 WorkListRemover DeadNodes(*this);
5552 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(0),
5554 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Result.getValue(2),
5557 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(1),
5561 // Finally, since the node is now dead, remove it from the graph.
5564 // Replace the uses of Ptr with uses of the updated base value.
5565 DAG.ReplaceAllUsesOfValueWith(Ptr, Result.getValue(isLoad ? 1 : 0),
5567 removeFromWorkList(Ptr.getNode());
5568 DAG.DeleteNode(Ptr.getNode());
5573 /// CombineToPostIndexedLoadStore - Try to combine a load / store with a
5574 /// add / sub of the base pointer node into a post-indexed load / store.
5575 /// The transformation folded the add / subtract into the new indexed
5576 /// load / store effectively and all of its uses are redirected to the
5577 /// new load / store.
5578 bool DAGCombiner::CombineToPostIndexedLoadStore(SDNode *N) {
5579 if (!LegalOperations)
5585 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) {
5586 if (LD->isIndexed())
5588 VT = LD->getMemoryVT();
5589 if (!TLI.isIndexedLoadLegal(ISD::POST_INC, VT) &&
5590 !TLI.isIndexedLoadLegal(ISD::POST_DEC, VT))
5592 Ptr = LD->getBasePtr();
5593 } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) {
5594 if (ST->isIndexed())
5596 VT = ST->getMemoryVT();
5597 if (!TLI.isIndexedStoreLegal(ISD::POST_INC, VT) &&
5598 !TLI.isIndexedStoreLegal(ISD::POST_DEC, VT))
5600 Ptr = ST->getBasePtr();
5606 if (Ptr.getNode()->hasOneUse())
5609 for (SDNode::use_iterator I = Ptr.getNode()->use_begin(),
5610 E = Ptr.getNode()->use_end(); I != E; ++I) {
5613 (Op->getOpcode() != ISD::ADD && Op->getOpcode() != ISD::SUB))
5618 ISD::MemIndexedMode AM = ISD::UNINDEXED;
5619 if (TLI.getPostIndexedAddressParts(N, Op, BasePtr, Offset, AM, DAG)) {
5620 // Don't create a indexed load / store with zero offset.
5621 if (isa<ConstantSDNode>(Offset) &&
5622 cast<ConstantSDNode>(Offset)->isNullValue())
5625 // Try turning it into a post-indexed load / store except when
5626 // 1) All uses are load / store ops that use it as base ptr.
5627 // 2) Op must be independent of N, i.e. Op is neither a predecessor
5628 // nor a successor of N. Otherwise, if Op is folded that would
5631 if (isa<FrameIndexSDNode>(BasePtr) || isa<RegisterSDNode>(BasePtr))
5635 bool TryNext = false;
5636 for (SDNode::use_iterator II = BasePtr.getNode()->use_begin(),
5637 EE = BasePtr.getNode()->use_end(); II != EE; ++II) {
5639 if (Use == Ptr.getNode())
5642 // If all the uses are load / store addresses, then don't do the
5644 if (Use->getOpcode() == ISD::ADD || Use->getOpcode() == ISD::SUB){
5645 bool RealUse = false;
5646 for (SDNode::use_iterator III = Use->use_begin(),
5647 EEE = Use->use_end(); III != EEE; ++III) {
5648 SDNode *UseUse = *III;
5649 if (!((UseUse->getOpcode() == ISD::LOAD &&
5650 cast<LoadSDNode>(UseUse)->getBasePtr().getNode() == Use) ||
5651 (UseUse->getOpcode() == ISD::STORE &&
5652 cast<StoreSDNode>(UseUse)->getBasePtr().getNode() == Use)))
5667 if (!Op->isPredecessorOf(N) && !N->isPredecessorOf(Op)) {
5668 SDValue Result = isLoad
5669 ? DAG.getIndexedLoad(SDValue(N,0), N->getDebugLoc(),
5670 BasePtr, Offset, AM)
5671 : DAG.getIndexedStore(SDValue(N,0), N->getDebugLoc(),
5672 BasePtr, Offset, AM);
5675 DEBUG(dbgs() << "\nReplacing.5 ";
5677 dbgs() << "\nWith: ";
5678 Result.getNode()->dump(&DAG);
5680 WorkListRemover DeadNodes(*this);
5682 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(0),
5684 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Result.getValue(2),
5687 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(1),
5691 // Finally, since the node is now dead, remove it from the graph.
5694 // Replace the uses of Use with uses of the updated base value.
5695 DAG.ReplaceAllUsesOfValueWith(SDValue(Op, 0),
5696 Result.getValue(isLoad ? 1 : 0),
5698 removeFromWorkList(Op);
5708 SDValue DAGCombiner::visitLOAD(SDNode *N) {
5709 LoadSDNode *LD = cast<LoadSDNode>(N);
5710 SDValue Chain = LD->getChain();
5711 SDValue Ptr = LD->getBasePtr();
5713 // If load is not volatile and there are no uses of the loaded value (and
5714 // the updated indexed value in case of indexed loads), change uses of the
5715 // chain value into uses of the chain input (i.e. delete the dead load).
5716 if (!LD->isVolatile()) {
5717 if (N->getValueType(1) == MVT::Other) {
5719 if (N->hasNUsesOfValue(0, 0)) {
5720 // It's not safe to use the two value CombineTo variant here. e.g.
5721 // v1, chain2 = load chain1, loc
5722 // v2, chain3 = load chain2, loc
5724 // Now we replace use of chain2 with chain1. This makes the second load
5725 // isomorphic to the one we are deleting, and thus makes this load live.
5726 DEBUG(dbgs() << "\nReplacing.6 ";
5728 dbgs() << "\nWith chain: ";
5729 Chain.getNode()->dump(&DAG);
5731 WorkListRemover DeadNodes(*this);
5732 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Chain, &DeadNodes);
5734 if (N->use_empty()) {
5735 removeFromWorkList(N);
5739 return SDValue(N, 0); // Return N so it doesn't get rechecked!
5743 assert(N->getValueType(2) == MVT::Other && "Malformed indexed loads?");
5744 if (N->hasNUsesOfValue(0, 0) && N->hasNUsesOfValue(0, 1)) {
5745 SDValue Undef = DAG.getUNDEF(N->getValueType(0));
5746 DEBUG(dbgs() << "\nReplacing.7 ";
5748 dbgs() << "\nWith: ";
5749 Undef.getNode()->dump(&DAG);
5750 dbgs() << " and 2 other values\n");
5751 WorkListRemover DeadNodes(*this);
5752 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Undef, &DeadNodes);
5753 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1),
5754 DAG.getUNDEF(N->getValueType(1)),
5756 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 2), Chain, &DeadNodes);
5757 removeFromWorkList(N);
5759 return SDValue(N, 0); // Return N so it doesn't get rechecked!
5764 // If this load is directly stored, replace the load value with the stored
5766 // TODO: Handle store large -> read small portion.
5767 // TODO: Handle TRUNCSTORE/LOADEXT
5768 if (LD->getExtensionType() == ISD::NON_EXTLOAD &&
5769 !LD->isVolatile()) {
5770 if (ISD::isNON_TRUNCStore(Chain.getNode())) {
5771 StoreSDNode *PrevST = cast<StoreSDNode>(Chain);
5772 if (PrevST->getBasePtr() == Ptr &&
5773 PrevST->getValue().getValueType() == N->getValueType(0))
5774 return CombineTo(N, Chain.getOperand(1), Chain);
5778 // Try to infer better alignment information than the load already has.
5779 if (OptLevel != CodeGenOpt::None && LD->isUnindexed()) {
5780 if (unsigned Align = DAG.InferPtrAlignment(Ptr)) {
5781 if (Align > LD->getAlignment())
5782 return DAG.getExtLoad(LD->getExtensionType(), LD->getValueType(0),
5784 Chain, Ptr, LD->getPointerInfo(),
5786 LD->isVolatile(), LD->isNonTemporal(), Align);
5791 // Walk up chain skipping non-aliasing memory nodes.
5792 SDValue BetterChain = FindBetterChain(N, Chain);
5794 // If there is a better chain.
5795 if (Chain != BetterChain) {
5798 // Replace the chain to void dependency.
5799 if (LD->getExtensionType() == ISD::NON_EXTLOAD) {
5800 ReplLoad = DAG.getLoad(N->getValueType(0), LD->getDebugLoc(),
5801 BetterChain, Ptr, LD->getPointerInfo(),
5802 LD->isVolatile(), LD->isNonTemporal(),
5803 LD->getAlignment());
5805 ReplLoad = DAG.getExtLoad(LD->getExtensionType(), LD->getValueType(0),
5807 BetterChain, Ptr, LD->getPointerInfo(),
5810 LD->isNonTemporal(),
5811 LD->getAlignment());
5814 // Create token factor to keep old chain connected.
5815 SDValue Token = DAG.getNode(ISD::TokenFactor, N->getDebugLoc(),
5816 MVT::Other, Chain, ReplLoad.getValue(1));
5818 // Make sure the new and old chains are cleaned up.
5819 AddToWorkList(Token.getNode());
5821 // Replace uses with load result and token factor. Don't add users
5823 return CombineTo(N, ReplLoad.getValue(0), Token, false);
5827 // Try transforming N to an indexed load.
5828 if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N))
5829 return SDValue(N, 0);
5834 /// CheckForMaskedLoad - Check to see if V is (and load (ptr), imm), where the
5835 /// load is having specific bytes cleared out. If so, return the byte size
5836 /// being masked out and the shift amount.
5837 static std::pair<unsigned, unsigned>
5838 CheckForMaskedLoad(SDValue V, SDValue Ptr, SDValue Chain) {
5839 std::pair<unsigned, unsigned> Result(0, 0);
5841 // Check for the structure we're looking for.
5842 if (V->getOpcode() != ISD::AND ||
5843 !isa<ConstantSDNode>(V->getOperand(1)) ||
5844 !ISD::isNormalLoad(V->getOperand(0).getNode()))
5847 // Check the chain and pointer.
5848 LoadSDNode *LD = cast<LoadSDNode>(V->getOperand(0));
5849 if (LD->getBasePtr() != Ptr) return Result; // Not from same pointer.
5851 // The store should be chained directly to the load or be an operand of a
5853 if (LD == Chain.getNode())
5855 else if (Chain->getOpcode() != ISD::TokenFactor)
5856 return Result; // Fail.
5859 for (unsigned i = 0, e = Chain->getNumOperands(); i != e; ++i)
5860 if (Chain->getOperand(i).getNode() == LD) {
5864 if (!isOk) return Result;
5867 // This only handles simple types.
5868 if (V.getValueType() != MVT::i16 &&
5869 V.getValueType() != MVT::i32 &&
5870 V.getValueType() != MVT::i64)
5873 // Check the constant mask. Invert it so that the bits being masked out are
5874 // 0 and the bits being kept are 1. Use getSExtValue so that leading bits
5875 // follow the sign bit for uniformity.
5876 uint64_t NotMask = ~cast<ConstantSDNode>(V->getOperand(1))->getSExtValue();
5877 unsigned NotMaskLZ = CountLeadingZeros_64(NotMask);
5878 if (NotMaskLZ & 7) return Result; // Must be multiple of a byte.
5879 unsigned NotMaskTZ = CountTrailingZeros_64(NotMask);
5880 if (NotMaskTZ & 7) return Result; // Must be multiple of a byte.
5881 if (NotMaskLZ == 64) return Result; // All zero mask.
5883 // See if we have a continuous run of bits. If so, we have 0*1+0*
5884 if (CountTrailingOnes_64(NotMask >> NotMaskTZ)+NotMaskTZ+NotMaskLZ != 64)
5887 // Adjust NotMaskLZ down to be from the actual size of the int instead of i64.
5888 if (V.getValueType() != MVT::i64 && NotMaskLZ)
5889 NotMaskLZ -= 64-V.getValueSizeInBits();
5891 unsigned MaskedBytes = (V.getValueSizeInBits()-NotMaskLZ-NotMaskTZ)/8;
5892 switch (MaskedBytes) {
5896 default: return Result; // All one mask, or 5-byte mask.
5899 // Verify that the first bit starts at a multiple of mask so that the access
5900 // is aligned the same as the access width.
5901 if (NotMaskTZ && NotMaskTZ/8 % MaskedBytes) return Result;
5903 Result.first = MaskedBytes;
5904 Result.second = NotMaskTZ/8;
5909 /// ShrinkLoadReplaceStoreWithStore - Check to see if IVal is something that
5910 /// provides a value as specified by MaskInfo. If so, replace the specified
5911 /// store with a narrower store of truncated IVal.
5913 ShrinkLoadReplaceStoreWithStore(const std::pair<unsigned, unsigned> &MaskInfo,
5914 SDValue IVal, StoreSDNode *St,
5916 unsigned NumBytes = MaskInfo.first;
5917 unsigned ByteShift = MaskInfo.second;
5918 SelectionDAG &DAG = DC->getDAG();
5920 // Check to see if IVal is all zeros in the part being masked in by the 'or'
5921 // that uses this. If not, this is not a replacement.
5922 APInt Mask = ~APInt::getBitsSet(IVal.getValueSizeInBits(),
5923 ByteShift*8, (ByteShift+NumBytes)*8);
5924 if (!DAG.MaskedValueIsZero(IVal, Mask)) return 0;
5926 // Check that it is legal on the target to do this. It is legal if the new
5927 // VT we're shrinking to (i8/i16/i32) is legal or we're still before type
5929 MVT VT = MVT::getIntegerVT(NumBytes*8);
5930 if (!DC->isTypeLegal(VT))
5933 // Okay, we can do this! Replace the 'St' store with a store of IVal that is
5934 // shifted by ByteShift and truncated down to NumBytes.
5936 IVal = DAG.getNode(ISD::SRL, IVal->getDebugLoc(), IVal.getValueType(), IVal,
5937 DAG.getConstant(ByteShift*8, DC->getShiftAmountTy()));
5939 // Figure out the offset for the store and the alignment of the access.
5941 unsigned NewAlign = St->getAlignment();
5943 if (DAG.getTargetLoweringInfo().isLittleEndian())
5944 StOffset = ByteShift;
5946 StOffset = IVal.getValueType().getStoreSize() - ByteShift - NumBytes;
5948 SDValue Ptr = St->getBasePtr();
5950 Ptr = DAG.getNode(ISD::ADD, IVal->getDebugLoc(), Ptr.getValueType(),
5951 Ptr, DAG.getConstant(StOffset, Ptr.getValueType()));
5952 NewAlign = MinAlign(NewAlign, StOffset);
5955 // Truncate down to the new size.
5956 IVal = DAG.getNode(ISD::TRUNCATE, IVal->getDebugLoc(), VT, IVal);
5959 return DAG.getStore(St->getChain(), St->getDebugLoc(), IVal, Ptr,
5960 St->getPointerInfo().getWithOffset(StOffset),
5961 false, false, NewAlign).getNode();
5965 /// ReduceLoadOpStoreWidth - Look for sequence of load / op / store where op is
5966 /// one of 'or', 'xor', and 'and' of immediates. If 'op' is only touching some
5967 /// of the loaded bits, try narrowing the load and store if it would end up
5968 /// being a win for performance or code size.
5969 SDValue DAGCombiner::ReduceLoadOpStoreWidth(SDNode *N) {
5970 StoreSDNode *ST = cast<StoreSDNode>(N);
5971 if (ST->isVolatile())
5974 SDValue Chain = ST->getChain();
5975 SDValue Value = ST->getValue();
5976 SDValue Ptr = ST->getBasePtr();
5977 EVT VT = Value.getValueType();
5979 if (ST->isTruncatingStore() || VT.isVector() || !Value.hasOneUse())
5982 unsigned Opc = Value.getOpcode();
5984 // If this is "store (or X, Y), P" and X is "(and (load P), cst)", where cst
5985 // is a byte mask indicating a consecutive number of bytes, check to see if
5986 // Y is known to provide just those bytes. If so, we try to replace the
5987 // load + replace + store sequence with a single (narrower) store, which makes
5989 if (Opc == ISD::OR) {
5990 std::pair<unsigned, unsigned> MaskedLoad;
5991 MaskedLoad = CheckForMaskedLoad(Value.getOperand(0), Ptr, Chain);
5992 if (MaskedLoad.first)
5993 if (SDNode *NewST = ShrinkLoadReplaceStoreWithStore(MaskedLoad,
5994 Value.getOperand(1), ST,this))
5995 return SDValue(NewST, 0);
5997 // Or is commutative, so try swapping X and Y.
5998 MaskedLoad = CheckForMaskedLoad(Value.getOperand(1), Ptr, Chain);
5999 if (MaskedLoad.first)
6000 if (SDNode *NewST = ShrinkLoadReplaceStoreWithStore(MaskedLoad,
6001 Value.getOperand(0), ST,this))
6002 return SDValue(NewST, 0);
6005 if ((Opc != ISD::OR && Opc != ISD::XOR && Opc != ISD::AND) ||
6006 Value.getOperand(1).getOpcode() != ISD::Constant)
6009 SDValue N0 = Value.getOperand(0);
6010 if (ISD::isNormalLoad(N0.getNode()) && N0.hasOneUse() &&
6011 Chain == SDValue(N0.getNode(), 1)) {
6012 LoadSDNode *LD = cast<LoadSDNode>(N0);
6013 if (LD->getBasePtr() != Ptr ||
6014 LD->getPointerInfo().getAddrSpace() !=
6015 ST->getPointerInfo().getAddrSpace())
6018 // Find the type to narrow it the load / op / store to.
6019 SDValue N1 = Value.getOperand(1);
6020 unsigned BitWidth = N1.getValueSizeInBits();
6021 APInt Imm = cast<ConstantSDNode>(N1)->getAPIntValue();
6022 if (Opc == ISD::AND)
6023 Imm ^= APInt::getAllOnesValue(BitWidth);
6024 if (Imm == 0 || Imm.isAllOnesValue())
6026 unsigned ShAmt = Imm.countTrailingZeros();
6027 unsigned MSB = BitWidth - Imm.countLeadingZeros() - 1;
6028 unsigned NewBW = NextPowerOf2(MSB - ShAmt);
6029 EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), NewBW);
6030 while (NewBW < BitWidth &&
6031 !(TLI.isOperationLegalOrCustom(Opc, NewVT) &&
6032 TLI.isNarrowingProfitable(VT, NewVT))) {
6033 NewBW = NextPowerOf2(NewBW);
6034 NewVT = EVT::getIntegerVT(*DAG.getContext(), NewBW);
6036 if (NewBW >= BitWidth)
6039 // If the lsb changed does not start at the type bitwidth boundary,
6040 // start at the previous one.
6042 ShAmt = (((ShAmt + NewBW - 1) / NewBW) * NewBW) - NewBW;
6043 APInt Mask = APInt::getBitsSet(BitWidth, ShAmt, ShAmt + NewBW);
6044 if ((Imm & Mask) == Imm) {
6045 APInt NewImm = (Imm & Mask).lshr(ShAmt).trunc(NewBW);
6046 if (Opc == ISD::AND)
6047 NewImm ^= APInt::getAllOnesValue(NewBW);
6048 uint64_t PtrOff = ShAmt / 8;
6049 // For big endian targets, we need to adjust the offset to the pointer to
6050 // load the correct bytes.
6051 if (TLI.isBigEndian())
6052 PtrOff = (BitWidth + 7 - NewBW) / 8 - PtrOff;
6054 unsigned NewAlign = MinAlign(LD->getAlignment(), PtrOff);
6055 const Type *NewVTTy = NewVT.getTypeForEVT(*DAG.getContext());
6056 if (NewAlign < TLI.getTargetData()->getABITypeAlignment(NewVTTy))
6059 SDValue NewPtr = DAG.getNode(ISD::ADD, LD->getDebugLoc(),
6060 Ptr.getValueType(), Ptr,
6061 DAG.getConstant(PtrOff, Ptr.getValueType()));
6062 SDValue NewLD = DAG.getLoad(NewVT, N0.getDebugLoc(),
6063 LD->getChain(), NewPtr,
6064 LD->getPointerInfo().getWithOffset(PtrOff),
6065 LD->isVolatile(), LD->isNonTemporal(),
6067 SDValue NewVal = DAG.getNode(Opc, Value.getDebugLoc(), NewVT, NewLD,
6068 DAG.getConstant(NewImm, NewVT));
6069 SDValue NewST = DAG.getStore(Chain, N->getDebugLoc(),
6071 ST->getPointerInfo().getWithOffset(PtrOff),
6072 false, false, NewAlign);
6074 AddToWorkList(NewPtr.getNode());
6075 AddToWorkList(NewLD.getNode());
6076 AddToWorkList(NewVal.getNode());
6077 WorkListRemover DeadNodes(*this);
6078 DAG.ReplaceAllUsesOfValueWith(N0.getValue(1), NewLD.getValue(1),
6088 SDValue DAGCombiner::visitSTORE(SDNode *N) {
6089 StoreSDNode *ST = cast<StoreSDNode>(N);
6090 SDValue Chain = ST->getChain();
6091 SDValue Value = ST->getValue();
6092 SDValue Ptr = ST->getBasePtr();
6094 // If this is a store of a bit convert, store the input value if the
6095 // resultant store does not need a higher alignment than the original.
6096 if (Value.getOpcode() == ISD::BITCAST && !ST->isTruncatingStore() &&
6097 ST->isUnindexed()) {
6098 unsigned OrigAlign = ST->getAlignment();
6099 EVT SVT = Value.getOperand(0).getValueType();
6100 unsigned Align = TLI.getTargetData()->
6101 getABITypeAlignment(SVT.getTypeForEVT(*DAG.getContext()));
6102 if (Align <= OrigAlign &&
6103 ((!LegalOperations && !ST->isVolatile()) ||
6104 TLI.isOperationLegalOrCustom(ISD::STORE, SVT)))
6105 return DAG.getStore(Chain, N->getDebugLoc(), Value.getOperand(0),
6106 Ptr, ST->getPointerInfo(), ST->isVolatile(),
6107 ST->isNonTemporal(), OrigAlign);
6110 // Turn 'store float 1.0, Ptr' -> 'store int 0x12345678, Ptr'
6111 if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(Value)) {
6112 // NOTE: If the original store is volatile, this transform must not increase
6113 // the number of stores. For example, on x86-32 an f64 can be stored in one
6114 // processor operation but an i64 (which is not legal) requires two. So the
6115 // transform should not be done in this case.
6116 if (Value.getOpcode() != ISD::TargetConstantFP) {
6118 switch (CFP->getValueType(0).getSimpleVT().SimpleTy) {
6119 default: llvm_unreachable("Unknown FP type");
6120 case MVT::f80: // We don't do this for these yet.
6125 if ((isTypeLegal(MVT::i32) && !LegalOperations && !ST->isVolatile()) ||
6126 TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i32)) {
6127 Tmp = DAG.getConstant((uint32_t)CFP->getValueAPF().
6128 bitcastToAPInt().getZExtValue(), MVT::i32);
6129 return DAG.getStore(Chain, N->getDebugLoc(), Tmp,
6130 Ptr, ST->getPointerInfo(), ST->isVolatile(),
6131 ST->isNonTemporal(), ST->getAlignment());
6135 if ((TLI.isTypeLegal(MVT::i64) && !LegalOperations &&
6136 !ST->isVolatile()) ||
6137 TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i64)) {
6138 Tmp = DAG.getConstant(CFP->getValueAPF().bitcastToAPInt().
6139 getZExtValue(), MVT::i64);
6140 return DAG.getStore(Chain, N->getDebugLoc(), Tmp,
6141 Ptr, ST->getPointerInfo(), ST->isVolatile(),
6142 ST->isNonTemporal(), ST->getAlignment());
6143 } else if (!ST->isVolatile() &&
6144 TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i32)) {
6145 // Many FP stores are not made apparent until after legalize, e.g. for
6146 // argument passing. Since this is so common, custom legalize the
6147 // 64-bit integer store into two 32-bit stores.
6148 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
6149 SDValue Lo = DAG.getConstant(Val & 0xFFFFFFFF, MVT::i32);
6150 SDValue Hi = DAG.getConstant(Val >> 32, MVT::i32);
6151 if (TLI.isBigEndian()) std::swap(Lo, Hi);
6153 unsigned Alignment = ST->getAlignment();
6154 bool isVolatile = ST->isVolatile();
6155 bool isNonTemporal = ST->isNonTemporal();
6157 SDValue St0 = DAG.getStore(Chain, ST->getDebugLoc(), Lo,
6158 Ptr, ST->getPointerInfo(),
6159 isVolatile, isNonTemporal,
6160 ST->getAlignment());
6161 Ptr = DAG.getNode(ISD::ADD, N->getDebugLoc(), Ptr.getValueType(), Ptr,
6162 DAG.getConstant(4, Ptr.getValueType()));
6163 Alignment = MinAlign(Alignment, 4U);
6164 SDValue St1 = DAG.getStore(Chain, ST->getDebugLoc(), Hi,
6165 Ptr, ST->getPointerInfo().getWithOffset(4),
6166 isVolatile, isNonTemporal,
6168 return DAG.getNode(ISD::TokenFactor, N->getDebugLoc(), MVT::Other,
6177 // Try to infer better alignment information than the store already has.
6178 if (OptLevel != CodeGenOpt::None && ST->isUnindexed()) {
6179 if (unsigned Align = DAG.InferPtrAlignment(Ptr)) {
6180 if (Align > ST->getAlignment())
6181 return DAG.getTruncStore(Chain, N->getDebugLoc(), Value,
6182 Ptr, ST->getPointerInfo(), ST->getMemoryVT(),
6183 ST->isVolatile(), ST->isNonTemporal(), Align);
6188 // Walk up chain skipping non-aliasing memory nodes.
6189 SDValue BetterChain = FindBetterChain(N, Chain);
6191 // If there is a better chain.
6192 if (Chain != BetterChain) {
6195 // Replace the chain to avoid dependency.
6196 if (ST->isTruncatingStore()) {
6197 ReplStore = DAG.getTruncStore(BetterChain, N->getDebugLoc(), Value, Ptr,
6198 ST->getPointerInfo(),
6199 ST->getMemoryVT(), ST->isVolatile(),
6200 ST->isNonTemporal(), ST->getAlignment());
6202 ReplStore = DAG.getStore(BetterChain, N->getDebugLoc(), Value, Ptr,
6203 ST->getPointerInfo(),
6204 ST->isVolatile(), ST->isNonTemporal(),
6205 ST->getAlignment());
6208 // Create token to keep both nodes around.
6209 SDValue Token = DAG.getNode(ISD::TokenFactor, N->getDebugLoc(),
6210 MVT::Other, Chain, ReplStore);
6212 // Make sure the new and old chains are cleaned up.
6213 AddToWorkList(Token.getNode());
6215 // Don't add users to work list.
6216 return CombineTo(N, Token, false);
6220 // Try transforming N to an indexed store.
6221 if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N))
6222 return SDValue(N, 0);
6224 // FIXME: is there such a thing as a truncating indexed store?
6225 if (ST->isTruncatingStore() && ST->isUnindexed() &&
6226 Value.getValueType().isInteger()) {
6227 // See if we can simplify the input to this truncstore with knowledge that
6228 // only the low bits are being used. For example:
6229 // "truncstore (or (shl x, 8), y), i8" -> "truncstore y, i8"
6231 GetDemandedBits(Value,
6232 APInt::getLowBitsSet(Value.getValueSizeInBits(),
6233 ST->getMemoryVT().getSizeInBits()));
6234 AddToWorkList(Value.getNode());
6235 if (Shorter.getNode())
6236 return DAG.getTruncStore(Chain, N->getDebugLoc(), Shorter,
6237 Ptr, ST->getPointerInfo(), ST->getMemoryVT(),
6238 ST->isVolatile(), ST->isNonTemporal(),
6239 ST->getAlignment());
6241 // Otherwise, see if we can simplify the operation with
6242 // SimplifyDemandedBits, which only works if the value has a single use.
6243 if (SimplifyDemandedBits(Value,
6244 APInt::getLowBitsSet(
6245 Value.getValueType().getScalarType().getSizeInBits(),
6246 ST->getMemoryVT().getScalarType().getSizeInBits())))
6247 return SDValue(N, 0);
6250 // If this is a load followed by a store to the same location, then the store
6252 if (LoadSDNode *Ld = dyn_cast<LoadSDNode>(Value)) {
6253 if (Ld->getBasePtr() == Ptr && ST->getMemoryVT() == Ld->getMemoryVT() &&
6254 ST->isUnindexed() && !ST->isVolatile() &&
6255 // There can't be any side effects between the load and store, such as
6257 Chain.reachesChainWithoutSideEffects(SDValue(Ld, 1))) {
6258 // The store is dead, remove it.
6263 // If this is an FP_ROUND or TRUNC followed by a store, fold this into a
6264 // truncating store. We can do this even if this is already a truncstore.
6265 if ((Value.getOpcode() == ISD::FP_ROUND || Value.getOpcode() == ISD::TRUNCATE)
6266 && Value.getNode()->hasOneUse() && ST->isUnindexed() &&
6267 TLI.isTruncStoreLegal(Value.getOperand(0).getValueType(),
6268 ST->getMemoryVT())) {
6269 return DAG.getTruncStore(Chain, N->getDebugLoc(), Value.getOperand(0),
6270 Ptr, ST->getPointerInfo(), ST->getMemoryVT(),
6271 ST->isVolatile(), ST->isNonTemporal(),
6272 ST->getAlignment());
6275 return ReduceLoadOpStoreWidth(N);
6278 SDValue DAGCombiner::visitINSERT_VECTOR_ELT(SDNode *N) {
6279 SDValue InVec = N->getOperand(0);
6280 SDValue InVal = N->getOperand(1);
6281 SDValue EltNo = N->getOperand(2);
6283 // If the inserted element is an UNDEF, just use the input vector.
6284 if (InVal.getOpcode() == ISD::UNDEF)
6287 // If the invec is a BUILD_VECTOR and if EltNo is a constant, build a new
6288 // vector with the inserted element.
6289 if (InVec.getOpcode() == ISD::BUILD_VECTOR && isa<ConstantSDNode>(EltNo)) {
6290 unsigned Elt = cast<ConstantSDNode>(EltNo)->getZExtValue();
6291 SmallVector<SDValue, 8> Ops(InVec.getNode()->op_begin(),
6292 InVec.getNode()->op_end());
6293 if (Elt < Ops.size())
6295 return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(),
6296 InVec.getValueType(), &Ops[0], Ops.size());
6298 // If the invec is an UNDEF and if EltNo is a constant, create a new
6299 // BUILD_VECTOR with undef elements and the inserted element.
6300 if (!LegalOperations && InVec.getOpcode() == ISD::UNDEF &&
6301 isa<ConstantSDNode>(EltNo)) {
6302 EVT VT = InVec.getValueType();
6303 EVT EltVT = VT.getVectorElementType();
6304 unsigned NElts = VT.getVectorNumElements();
6305 SmallVector<SDValue, 8> Ops(NElts, DAG.getUNDEF(EltVT));
6307 unsigned Elt = cast<ConstantSDNode>(EltNo)->getZExtValue();
6308 if (Elt < Ops.size())
6310 return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(),
6311 InVec.getValueType(), &Ops[0], Ops.size());
6316 SDValue DAGCombiner::visitEXTRACT_VECTOR_ELT(SDNode *N) {
6317 // (vextract (scalar_to_vector val, 0) -> val
6318 SDValue InVec = N->getOperand(0);
6320 if (InVec.getOpcode() == ISD::SCALAR_TO_VECTOR) {
6321 // Check if the result type doesn't match the inserted element type. A
6322 // SCALAR_TO_VECTOR may truncate the inserted element and the
6323 // EXTRACT_VECTOR_ELT may widen the extracted vector.
6324 SDValue InOp = InVec.getOperand(0);
6325 EVT NVT = N->getValueType(0);
6326 if (InOp.getValueType() != NVT) {
6327 assert(InOp.getValueType().isInteger() && NVT.isInteger());
6328 return DAG.getSExtOrTrunc(InOp, InVec.getDebugLoc(), NVT);
6333 // Perform only after legalization to ensure build_vector / vector_shuffle
6334 // optimizations have already been done.
6335 if (!LegalOperations) return SDValue();
6337 // (vextract (v4f32 load $addr), c) -> (f32 load $addr+c*size)
6338 // (vextract (v4f32 s2v (f32 load $addr)), c) -> (f32 load $addr+c*size)
6339 // (vextract (v4f32 shuffle (load $addr), <1,u,u,u>), 0) -> (f32 load $addr)
6340 SDValue EltNo = N->getOperand(1);
6342 if (isa<ConstantSDNode>(EltNo)) {
6343 int Elt = cast<ConstantSDNode>(EltNo)->getZExtValue();
6344 bool NewLoad = false;
6345 bool BCNumEltsChanged = false;
6346 EVT VT = InVec.getValueType();
6347 EVT ExtVT = VT.getVectorElementType();
6350 if (InVec.getOpcode() == ISD::BITCAST) {
6351 EVT BCVT = InVec.getOperand(0).getValueType();
6352 if (!BCVT.isVector() || ExtVT.bitsGT(BCVT.getVectorElementType()))
6354 if (VT.getVectorNumElements() != BCVT.getVectorNumElements())
6355 BCNumEltsChanged = true;
6356 InVec = InVec.getOperand(0);
6357 ExtVT = BCVT.getVectorElementType();
6361 LoadSDNode *LN0 = NULL;
6362 const ShuffleVectorSDNode *SVN = NULL;
6363 if (ISD::isNormalLoad(InVec.getNode())) {
6364 LN0 = cast<LoadSDNode>(InVec);
6365 } else if (InVec.getOpcode() == ISD::SCALAR_TO_VECTOR &&
6366 InVec.getOperand(0).getValueType() == ExtVT &&
6367 ISD::isNormalLoad(InVec.getOperand(0).getNode())) {
6368 LN0 = cast<LoadSDNode>(InVec.getOperand(0));
6369 } else if ((SVN = dyn_cast<ShuffleVectorSDNode>(InVec))) {
6370 // (vextract (vector_shuffle (load $addr), v2, <1, u, u, u>), 1)
6372 // (load $addr+1*size)
6374 // If the bit convert changed the number of elements, it is unsafe
6375 // to examine the mask.
6376 if (BCNumEltsChanged)
6379 // Select the input vector, guarding against out of range extract vector.
6380 unsigned NumElems = VT.getVectorNumElements();
6381 int Idx = (Elt > (int)NumElems) ? -1 : SVN->getMaskElt(Elt);
6382 InVec = (Idx < (int)NumElems) ? InVec.getOperand(0) : InVec.getOperand(1);
6384 if (InVec.getOpcode() == ISD::BITCAST)
6385 InVec = InVec.getOperand(0);
6386 if (ISD::isNormalLoad(InVec.getNode())) {
6387 LN0 = cast<LoadSDNode>(InVec);
6388 Elt = (Idx < (int)NumElems) ? Idx : Idx - (int)NumElems;
6392 if (!LN0 || !LN0->hasOneUse() || LN0->isVolatile())
6395 // If Idx was -1 above, Elt is going to be -1, so just return undef.
6397 return DAG.getUNDEF(LN0->getBasePtr().getValueType());
6399 unsigned Align = LN0->getAlignment();
6401 // Check the resultant load doesn't need a higher alignment than the
6405 ->getABITypeAlignment(LVT.getTypeForEVT(*DAG.getContext()));
6407 if (NewAlign > Align || !TLI.isOperationLegalOrCustom(ISD::LOAD, LVT))
6413 SDValue NewPtr = LN0->getBasePtr();
6414 unsigned PtrOff = 0;
6417 PtrOff = LVT.getSizeInBits() * Elt / 8;
6418 EVT PtrType = NewPtr.getValueType();
6419 if (TLI.isBigEndian())
6420 PtrOff = VT.getSizeInBits() / 8 - PtrOff;
6421 NewPtr = DAG.getNode(ISD::ADD, N->getDebugLoc(), PtrType, NewPtr,
6422 DAG.getConstant(PtrOff, PtrType));
6425 return DAG.getLoad(LVT, N->getDebugLoc(), LN0->getChain(), NewPtr,
6426 LN0->getPointerInfo().getWithOffset(PtrOff),
6427 LN0->isVolatile(), LN0->isNonTemporal(), Align);
6433 SDValue DAGCombiner::visitBUILD_VECTOR(SDNode *N) {
6434 unsigned NumInScalars = N->getNumOperands();
6435 EVT VT = N->getValueType(0);
6437 // Check to see if this is a BUILD_VECTOR of a bunch of EXTRACT_VECTOR_ELT
6438 // operations. If so, and if the EXTRACT_VECTOR_ELT vector inputs come from
6439 // at most two distinct vectors, turn this into a shuffle node.
6440 SDValue VecIn1, VecIn2;
6441 for (unsigned i = 0; i != NumInScalars; ++i) {
6442 // Ignore undef inputs.
6443 if (N->getOperand(i).getOpcode() == ISD::UNDEF) continue;
6445 // If this input is something other than a EXTRACT_VECTOR_ELT with a
6446 // constant index, bail out.
6447 if (N->getOperand(i).getOpcode() != ISD::EXTRACT_VECTOR_ELT ||
6448 !isa<ConstantSDNode>(N->getOperand(i).getOperand(1))) {
6449 VecIn1 = VecIn2 = SDValue(0, 0);
6453 // If the input vector type disagrees with the result of the build_vector,
6454 // we can't make a shuffle.
6455 SDValue ExtractedFromVec = N->getOperand(i).getOperand(0);
6456 if (ExtractedFromVec.getValueType() != VT) {
6457 VecIn1 = VecIn2 = SDValue(0, 0);
6461 // Otherwise, remember this. We allow up to two distinct input vectors.
6462 if (ExtractedFromVec == VecIn1 || ExtractedFromVec == VecIn2)
6465 if (VecIn1.getNode() == 0) {
6466 VecIn1 = ExtractedFromVec;
6467 } else if (VecIn2.getNode() == 0) {
6468 VecIn2 = ExtractedFromVec;
6471 VecIn1 = VecIn2 = SDValue(0, 0);
6476 // If everything is good, we can make a shuffle operation.
6477 if (VecIn1.getNode()) {
6478 SmallVector<int, 8> Mask;
6479 for (unsigned i = 0; i != NumInScalars; ++i) {
6480 if (N->getOperand(i).getOpcode() == ISD::UNDEF) {
6485 // If extracting from the first vector, just use the index directly.
6486 SDValue Extract = N->getOperand(i);
6487 SDValue ExtVal = Extract.getOperand(1);
6488 if (Extract.getOperand(0) == VecIn1) {
6489 unsigned ExtIndex = cast<ConstantSDNode>(ExtVal)->getZExtValue();
6490 if (ExtIndex > VT.getVectorNumElements())
6493 Mask.push_back(ExtIndex);
6497 // Otherwise, use InIdx + VecSize
6498 unsigned Idx = cast<ConstantSDNode>(ExtVal)->getZExtValue();
6499 Mask.push_back(Idx+NumInScalars);
6502 // Add count and size info.
6503 if (!isTypeLegal(VT))
6506 // Return the new VECTOR_SHUFFLE node.
6509 Ops[1] = VecIn2.getNode() ? VecIn2 : DAG.getUNDEF(VT);
6510 return DAG.getVectorShuffle(VT, N->getDebugLoc(), Ops[0], Ops[1], &Mask[0]);
6516 SDValue DAGCombiner::visitCONCAT_VECTORS(SDNode *N) {
6517 // TODO: Check to see if this is a CONCAT_VECTORS of a bunch of
6518 // EXTRACT_SUBVECTOR operations. If so, and if the EXTRACT_SUBVECTOR vector
6519 // inputs come from at most two distinct vectors, turn this into a shuffle
6522 // If we only have one input vector, we don't need to do any concatenation.
6523 if (N->getNumOperands() == 1)
6524 return N->getOperand(0);
6529 SDValue DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) {
6530 EVT VT = N->getValueType(0);
6531 unsigned NumElts = VT.getVectorNumElements();
6533 SDValue N0 = N->getOperand(0);
6535 assert(N0.getValueType().getVectorNumElements() == NumElts &&
6536 "Vector shuffle must be normalized in DAG");
6538 // FIXME: implement canonicalizations from DAG.getVectorShuffle()
6540 // If it is a splat, check if the argument vector is another splat or a
6541 // build_vector with all scalar elements the same.
6542 ShuffleVectorSDNode *SVN = cast<ShuffleVectorSDNode>(N);
6543 if (SVN->isSplat() && SVN->getSplatIndex() < (int)NumElts) {
6544 SDNode *V = N0.getNode();
6546 // If this is a bit convert that changes the element type of the vector but
6547 // not the number of vector elements, look through it. Be careful not to
6548 // look though conversions that change things like v4f32 to v2f64.
6549 if (V->getOpcode() == ISD::BITCAST) {
6550 SDValue ConvInput = V->getOperand(0);
6551 if (ConvInput.getValueType().isVector() &&
6552 ConvInput.getValueType().getVectorNumElements() == NumElts)
6553 V = ConvInput.getNode();
6556 if (V->getOpcode() == ISD::BUILD_VECTOR) {
6557 assert(V->getNumOperands() == NumElts &&
6558 "BUILD_VECTOR has wrong number of operands");
6560 bool AllSame = true;
6561 for (unsigned i = 0; i != NumElts; ++i) {
6562 if (V->getOperand(i).getOpcode() != ISD::UNDEF) {
6563 Base = V->getOperand(i);
6567 // Splat of <u, u, u, u>, return <u, u, u, u>
6568 if (!Base.getNode())
6570 for (unsigned i = 0; i != NumElts; ++i) {
6571 if (V->getOperand(i) != Base) {
6576 // Splat of <x, x, x, x>, return <x, x, x, x>
6584 SDValue DAGCombiner::visitMEMBARRIER(SDNode* N) {
6585 if (!TLI.getShouldFoldAtomicFences())
6588 SDValue atomic = N->getOperand(0);
6589 switch (atomic.getOpcode()) {
6590 case ISD::ATOMIC_CMP_SWAP:
6591 case ISD::ATOMIC_SWAP:
6592 case ISD::ATOMIC_LOAD_ADD:
6593 case ISD::ATOMIC_LOAD_SUB:
6594 case ISD::ATOMIC_LOAD_AND:
6595 case ISD::ATOMIC_LOAD_OR:
6596 case ISD::ATOMIC_LOAD_XOR:
6597 case ISD::ATOMIC_LOAD_NAND:
6598 case ISD::ATOMIC_LOAD_MIN:
6599 case ISD::ATOMIC_LOAD_MAX:
6600 case ISD::ATOMIC_LOAD_UMIN:
6601 case ISD::ATOMIC_LOAD_UMAX:
6607 SDValue fence = atomic.getOperand(0);
6608 if (fence.getOpcode() != ISD::MEMBARRIER)
6611 switch (atomic.getOpcode()) {
6612 case ISD::ATOMIC_CMP_SWAP:
6613 return SDValue(DAG.UpdateNodeOperands(atomic.getNode(),
6614 fence.getOperand(0),
6615 atomic.getOperand(1), atomic.getOperand(2),
6616 atomic.getOperand(3)), atomic.getResNo());
6617 case ISD::ATOMIC_SWAP:
6618 case ISD::ATOMIC_LOAD_ADD:
6619 case ISD::ATOMIC_LOAD_SUB:
6620 case ISD::ATOMIC_LOAD_AND:
6621 case ISD::ATOMIC_LOAD_OR:
6622 case ISD::ATOMIC_LOAD_XOR:
6623 case ISD::ATOMIC_LOAD_NAND:
6624 case ISD::ATOMIC_LOAD_MIN:
6625 case ISD::ATOMIC_LOAD_MAX:
6626 case ISD::ATOMIC_LOAD_UMIN:
6627 case ISD::ATOMIC_LOAD_UMAX:
6628 return SDValue(DAG.UpdateNodeOperands(atomic.getNode(),
6629 fence.getOperand(0),
6630 atomic.getOperand(1), atomic.getOperand(2)),
6637 /// XformToShuffleWithZero - Returns a vector_shuffle if it able to transform
6638 /// an AND to a vector_shuffle with the destination vector and a zero vector.
6639 /// e.g. AND V, <0xffffffff, 0, 0xffffffff, 0>. ==>
6640 /// vector_shuffle V, Zero, <0, 4, 2, 4>
6641 SDValue DAGCombiner::XformToShuffleWithZero(SDNode *N) {
6642 EVT VT = N->getValueType(0);
6643 DebugLoc dl = N->getDebugLoc();
6644 SDValue LHS = N->getOperand(0);
6645 SDValue RHS = N->getOperand(1);
6646 if (N->getOpcode() == ISD::AND) {
6647 if (RHS.getOpcode() == ISD::BITCAST)
6648 RHS = RHS.getOperand(0);
6649 if (RHS.getOpcode() == ISD::BUILD_VECTOR) {
6650 SmallVector<int, 8> Indices;
6651 unsigned NumElts = RHS.getNumOperands();
6652 for (unsigned i = 0; i != NumElts; ++i) {
6653 SDValue Elt = RHS.getOperand(i);
6654 if (!isa<ConstantSDNode>(Elt))
6656 else if (cast<ConstantSDNode>(Elt)->isAllOnesValue())
6657 Indices.push_back(i);
6658 else if (cast<ConstantSDNode>(Elt)->isNullValue())
6659 Indices.push_back(NumElts);
6664 // Let's see if the target supports this vector_shuffle.
6665 EVT RVT = RHS.getValueType();
6666 if (!TLI.isVectorClearMaskLegal(Indices, RVT))
6669 // Return the new VECTOR_SHUFFLE node.
6670 EVT EltVT = RVT.getVectorElementType();
6671 SmallVector<SDValue,8> ZeroOps(RVT.getVectorNumElements(),
6672 DAG.getConstant(0, EltVT));
6673 SDValue Zero = DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(),
6674 RVT, &ZeroOps[0], ZeroOps.size());
6675 LHS = DAG.getNode(ISD::BITCAST, dl, RVT, LHS);
6676 SDValue Shuf = DAG.getVectorShuffle(RVT, dl, LHS, Zero, &Indices[0]);
6677 return DAG.getNode(ISD::BITCAST, dl, VT, Shuf);
6684 /// SimplifyVBinOp - Visit a binary vector operation, like ADD.
6685 SDValue DAGCombiner::SimplifyVBinOp(SDNode *N) {
6686 // After legalize, the target may be depending on adds and other
6687 // binary ops to provide legal ways to construct constants or other
6688 // things. Simplifying them may result in a loss of legality.
6689 if (LegalOperations) return SDValue();
6691 assert(N->getValueType(0).isVector() &&
6692 "SimplifyVBinOp only works on vectors!");
6694 SDValue LHS = N->getOperand(0);
6695 SDValue RHS = N->getOperand(1);
6696 SDValue Shuffle = XformToShuffleWithZero(N);
6697 if (Shuffle.getNode()) return Shuffle;
6699 // If the LHS and RHS are BUILD_VECTOR nodes, see if we can constant fold
6701 if (LHS.getOpcode() == ISD::BUILD_VECTOR &&
6702 RHS.getOpcode() == ISD::BUILD_VECTOR) {
6703 SmallVector<SDValue, 8> Ops;
6704 for (unsigned i = 0, e = LHS.getNumOperands(); i != e; ++i) {
6705 SDValue LHSOp = LHS.getOperand(i);
6706 SDValue RHSOp = RHS.getOperand(i);
6707 // If these two elements can't be folded, bail out.
6708 if ((LHSOp.getOpcode() != ISD::UNDEF &&
6709 LHSOp.getOpcode() != ISD::Constant &&
6710 LHSOp.getOpcode() != ISD::ConstantFP) ||
6711 (RHSOp.getOpcode() != ISD::UNDEF &&
6712 RHSOp.getOpcode() != ISD::Constant &&
6713 RHSOp.getOpcode() != ISD::ConstantFP))
6716 // Can't fold divide by zero.
6717 if (N->getOpcode() == ISD::SDIV || N->getOpcode() == ISD::UDIV ||
6718 N->getOpcode() == ISD::FDIV) {
6719 if ((RHSOp.getOpcode() == ISD::Constant &&
6720 cast<ConstantSDNode>(RHSOp.getNode())->isNullValue()) ||
6721 (RHSOp.getOpcode() == ISD::ConstantFP &&
6722 cast<ConstantFPSDNode>(RHSOp.getNode())->getValueAPF().isZero()))
6726 EVT VT = LHSOp.getValueType();
6727 assert(RHSOp.getValueType() == VT &&
6728 "SimplifyVBinOp with different BUILD_VECTOR element types");
6729 SDValue FoldOp = DAG.getNode(N->getOpcode(), LHS.getDebugLoc(), VT,
6731 if (FoldOp.getOpcode() != ISD::UNDEF &&
6732 FoldOp.getOpcode() != ISD::Constant &&
6733 FoldOp.getOpcode() != ISD::ConstantFP)
6735 Ops.push_back(FoldOp);
6736 AddToWorkList(FoldOp.getNode());
6739 if (Ops.size() == LHS.getNumOperands())
6740 return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(),
6741 LHS.getValueType(), &Ops[0], Ops.size());
6747 SDValue DAGCombiner::SimplifySelect(DebugLoc DL, SDValue N0,
6748 SDValue N1, SDValue N2){
6749 assert(N0.getOpcode() ==ISD::SETCC && "First argument must be a SetCC node!");
6751 SDValue SCC = SimplifySelectCC(DL, N0.getOperand(0), N0.getOperand(1), N1, N2,
6752 cast<CondCodeSDNode>(N0.getOperand(2))->get());
6754 // If we got a simplified select_cc node back from SimplifySelectCC, then
6755 // break it down into a new SETCC node, and a new SELECT node, and then return
6756 // the SELECT node, since we were called with a SELECT node.
6757 if (SCC.getNode()) {
6758 // Check to see if we got a select_cc back (to turn into setcc/select).
6759 // Otherwise, just return whatever node we got back, like fabs.
6760 if (SCC.getOpcode() == ISD::SELECT_CC) {
6761 SDValue SETCC = DAG.getNode(ISD::SETCC, N0.getDebugLoc(),
6763 SCC.getOperand(0), SCC.getOperand(1),
6765 AddToWorkList(SETCC.getNode());
6766 return DAG.getNode(ISD::SELECT, SCC.getDebugLoc(), SCC.getValueType(),
6767 SCC.getOperand(2), SCC.getOperand(3), SETCC);
6775 /// SimplifySelectOps - Given a SELECT or a SELECT_CC node, where LHS and RHS
6776 /// are the two values being selected between, see if we can simplify the
6777 /// select. Callers of this should assume that TheSelect is deleted if this
6778 /// returns true. As such, they should return the appropriate thing (e.g. the
6779 /// node) back to the top-level of the DAG combiner loop to avoid it being
6781 bool DAGCombiner::SimplifySelectOps(SDNode *TheSelect, SDValue LHS,
6784 // If this is a select from two identical things, try to pull the operation
6785 // through the select.
6786 if (LHS.getOpcode() != RHS.getOpcode() ||
6787 !LHS.hasOneUse() || !RHS.hasOneUse())
6790 // If this is a load and the token chain is identical, replace the select
6791 // of two loads with a load through a select of the address to load from.
6792 // This triggers in things like "select bool X, 10.0, 123.0" after the FP
6793 // constants have been dropped into the constant pool.
6794 if (LHS.getOpcode() == ISD::LOAD) {
6795 LoadSDNode *LLD = cast<LoadSDNode>(LHS);
6796 LoadSDNode *RLD = cast<LoadSDNode>(RHS);
6798 // Token chains must be identical.
6799 if (LHS.getOperand(0) != RHS.getOperand(0) ||
6800 // Do not let this transformation reduce the number of volatile loads.
6801 LLD->isVolatile() || RLD->isVolatile() ||
6802 // If this is an EXTLOAD, the VT's must match.
6803 LLD->getMemoryVT() != RLD->getMemoryVT() ||
6804 // If this is an EXTLOAD, the kind of extension must match.
6805 (LLD->getExtensionType() != RLD->getExtensionType() &&
6806 // The only exception is if one of the extensions is anyext.
6807 LLD->getExtensionType() != ISD::EXTLOAD &&
6808 RLD->getExtensionType() != ISD::EXTLOAD) ||
6809 // FIXME: this discards src value information. This is
6810 // over-conservative. It would be beneficial to be able to remember
6811 // both potential memory locations. Since we are discarding
6812 // src value info, don't do the transformation if the memory
6813 // locations are not in the default address space.
6814 LLD->getPointerInfo().getAddrSpace() != 0 ||
6815 RLD->getPointerInfo().getAddrSpace() != 0)
6818 // Check that the select condition doesn't reach either load. If so,
6819 // folding this will induce a cycle into the DAG. If not, this is safe to
6820 // xform, so create a select of the addresses.
6822 if (TheSelect->getOpcode() == ISD::SELECT) {
6823 SDNode *CondNode = TheSelect->getOperand(0).getNode();
6824 if ((LLD->hasAnyUseOfValue(1) && LLD->isPredecessorOf(CondNode)) ||
6825 (RLD->hasAnyUseOfValue(1) && RLD->isPredecessorOf(CondNode)))
6827 Addr = DAG.getNode(ISD::SELECT, TheSelect->getDebugLoc(),
6828 LLD->getBasePtr().getValueType(),
6829 TheSelect->getOperand(0), LLD->getBasePtr(),
6831 } else { // Otherwise SELECT_CC
6832 SDNode *CondLHS = TheSelect->getOperand(0).getNode();
6833 SDNode *CondRHS = TheSelect->getOperand(1).getNode();
6835 if ((LLD->hasAnyUseOfValue(1) &&
6836 (LLD->isPredecessorOf(CondLHS) || LLD->isPredecessorOf(CondRHS))) ||
6837 (LLD->hasAnyUseOfValue(1) &&
6838 (LLD->isPredecessorOf(CondLHS) || LLD->isPredecessorOf(CondRHS))))
6841 Addr = DAG.getNode(ISD::SELECT_CC, TheSelect->getDebugLoc(),
6842 LLD->getBasePtr().getValueType(),
6843 TheSelect->getOperand(0),
6844 TheSelect->getOperand(1),
6845 LLD->getBasePtr(), RLD->getBasePtr(),
6846 TheSelect->getOperand(4));
6850 if (LLD->getExtensionType() == ISD::NON_EXTLOAD) {
6851 Load = DAG.getLoad(TheSelect->getValueType(0),
6852 TheSelect->getDebugLoc(),
6853 // FIXME: Discards pointer info.
6854 LLD->getChain(), Addr, MachinePointerInfo(),
6855 LLD->isVolatile(), LLD->isNonTemporal(),
6856 LLD->getAlignment());
6858 Load = DAG.getExtLoad(LLD->getExtensionType() == ISD::EXTLOAD ?
6859 RLD->getExtensionType() : LLD->getExtensionType(),
6860 TheSelect->getValueType(0),
6861 TheSelect->getDebugLoc(),
6862 // FIXME: Discards pointer info.
6863 LLD->getChain(), Addr, MachinePointerInfo(),
6864 LLD->getMemoryVT(), LLD->isVolatile(),
6865 LLD->isNonTemporal(), LLD->getAlignment());
6868 // Users of the select now use the result of the load.
6869 CombineTo(TheSelect, Load);
6871 // Users of the old loads now use the new load's chain. We know the
6872 // old-load value is dead now.
6873 CombineTo(LHS.getNode(), Load.getValue(0), Load.getValue(1));
6874 CombineTo(RHS.getNode(), Load.getValue(0), Load.getValue(1));
6881 /// SimplifySelectCC - Simplify an expression of the form (N0 cond N1) ? N2 : N3
6882 /// where 'cond' is the comparison specified by CC.
6883 SDValue DAGCombiner::SimplifySelectCC(DebugLoc DL, SDValue N0, SDValue N1,
6884 SDValue N2, SDValue N3,
6885 ISD::CondCode CC, bool NotExtCompare) {
6886 // (x ? y : y) -> y.
6887 if (N2 == N3) return N2;
6889 EVT VT = N2.getValueType();
6890 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode());
6891 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2.getNode());
6892 ConstantSDNode *N3C = dyn_cast<ConstantSDNode>(N3.getNode());
6894 // Determine if the condition we're dealing with is constant
6895 SDValue SCC = SimplifySetCC(TLI.getSetCCResultType(N0.getValueType()),
6896 N0, N1, CC, DL, false);
6897 if (SCC.getNode()) AddToWorkList(SCC.getNode());
6898 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.getNode());
6900 // fold select_cc true, x, y -> x
6901 if (SCCC && !SCCC->isNullValue())
6903 // fold select_cc false, x, y -> y
6904 if (SCCC && SCCC->isNullValue())
6907 // Check to see if we can simplify the select into an fabs node
6908 if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N1)) {
6909 // Allow either -0.0 or 0.0
6910 if (CFP->getValueAPF().isZero()) {
6911 // select (setg[te] X, +/-0.0), X, fneg(X) -> fabs
6912 if ((CC == ISD::SETGE || CC == ISD::SETGT) &&
6913 N0 == N2 && N3.getOpcode() == ISD::FNEG &&
6914 N2 == N3.getOperand(0))
6915 return DAG.getNode(ISD::FABS, DL, VT, N0);
6917 // select (setl[te] X, +/-0.0), fneg(X), X -> fabs
6918 if ((CC == ISD::SETLT || CC == ISD::SETLE) &&
6919 N0 == N3 && N2.getOpcode() == ISD::FNEG &&
6920 N2.getOperand(0) == N3)
6921 return DAG.getNode(ISD::FABS, DL, VT, N3);
6925 // Turn "(a cond b) ? 1.0f : 2.0f" into "load (tmp + ((a cond b) ? 0 : 4)"
6926 // where "tmp" is a constant pool entry containing an array with 1.0 and 2.0
6927 // in it. This is a win when the constant is not otherwise available because
6928 // it replaces two constant pool loads with one. We only do this if the FP
6929 // type is known to be legal, because if it isn't, then we are before legalize
6930 // types an we want the other legalization to happen first (e.g. to avoid
6931 // messing with soft float) and if the ConstantFP is not legal, because if
6932 // it is legal, we may not need to store the FP constant in a constant pool.
6933 if (ConstantFPSDNode *TV = dyn_cast<ConstantFPSDNode>(N2))
6934 if (ConstantFPSDNode *FV = dyn_cast<ConstantFPSDNode>(N3)) {
6935 if (TLI.isTypeLegal(N2.getValueType()) &&
6936 (TLI.getOperationAction(ISD::ConstantFP, N2.getValueType()) !=
6937 TargetLowering::Legal) &&
6938 // If both constants have multiple uses, then we won't need to do an
6939 // extra load, they are likely around in registers for other users.
6940 (TV->hasOneUse() || FV->hasOneUse())) {
6941 Constant *Elts[] = {
6942 const_cast<ConstantFP*>(FV->getConstantFPValue()),
6943 const_cast<ConstantFP*>(TV->getConstantFPValue())
6945 const Type *FPTy = Elts[0]->getType();
6946 const TargetData &TD = *TLI.getTargetData();
6948 // Create a ConstantArray of the two constants.
6949 Constant *CA = ConstantArray::get(ArrayType::get(FPTy, 2), Elts, 2);
6950 SDValue CPIdx = DAG.getConstantPool(CA, TLI.getPointerTy(),
6951 TD.getPrefTypeAlignment(FPTy));
6952 unsigned Alignment = cast<ConstantPoolSDNode>(CPIdx)->getAlignment();
6954 // Get the offsets to the 0 and 1 element of the array so that we can
6955 // select between them.
6956 SDValue Zero = DAG.getIntPtrConstant(0);
6957 unsigned EltSize = (unsigned)TD.getTypeAllocSize(Elts[0]->getType());
6958 SDValue One = DAG.getIntPtrConstant(EltSize);
6960 SDValue Cond = DAG.getSetCC(DL,
6961 TLI.getSetCCResultType(N0.getValueType()),
6963 SDValue CstOffset = DAG.getNode(ISD::SELECT, DL, Zero.getValueType(),
6965 CPIdx = DAG.getNode(ISD::ADD, DL, TLI.getPointerTy(), CPIdx,
6967 return DAG.getLoad(TV->getValueType(0), DL, DAG.getEntryNode(), CPIdx,
6968 MachinePointerInfo::getConstantPool(), false,
6974 // Check to see if we can perform the "gzip trick", transforming
6975 // (select_cc setlt X, 0, A, 0) -> (and (sra X, (sub size(X), 1), A)
6976 if (N1C && N3C && N3C->isNullValue() && CC == ISD::SETLT &&
6977 N0.getValueType().isInteger() &&
6978 N2.getValueType().isInteger() &&
6979 (N1C->isNullValue() || // (a < 0) ? b : 0
6980 (N1C->getAPIntValue() == 1 && N0 == N2))) { // (a < 1) ? a : 0
6981 EVT XType = N0.getValueType();
6982 EVT AType = N2.getValueType();
6983 if (XType.bitsGE(AType)) {
6984 // and (sra X, size(X)-1, A) -> "and (srl X, C2), A" iff A is a
6985 // single-bit constant.
6986 if (N2C && ((N2C->getAPIntValue() & (N2C->getAPIntValue()-1)) == 0)) {
6987 unsigned ShCtV = N2C->getAPIntValue().logBase2();
6988 ShCtV = XType.getSizeInBits()-ShCtV-1;
6989 SDValue ShCt = DAG.getConstant(ShCtV, getShiftAmountTy());
6990 SDValue Shift = DAG.getNode(ISD::SRL, N0.getDebugLoc(),
6992 AddToWorkList(Shift.getNode());
6994 if (XType.bitsGT(AType)) {
6995 Shift = DAG.getNode(ISD::TRUNCATE, DL, AType, Shift);
6996 AddToWorkList(Shift.getNode());
6999 return DAG.getNode(ISD::AND, DL, AType, Shift, N2);
7002 SDValue Shift = DAG.getNode(ISD::SRA, N0.getDebugLoc(),
7004 DAG.getConstant(XType.getSizeInBits()-1,
7005 getShiftAmountTy()));
7006 AddToWorkList(Shift.getNode());
7008 if (XType.bitsGT(AType)) {
7009 Shift = DAG.getNode(ISD::TRUNCATE, DL, AType, Shift);
7010 AddToWorkList(Shift.getNode());
7013 return DAG.getNode(ISD::AND, DL, AType, Shift, N2);
7017 // fold (select_cc seteq (and x, y), 0, 0, A) -> (and (shr (shl x)) A)
7018 // where y is has a single bit set.
7019 // A plaintext description would be, we can turn the SELECT_CC into an AND
7020 // when the condition can be materialized as an all-ones register. Any
7021 // single bit-test can be materialized as an all-ones register with
7022 // shift-left and shift-right-arith.
7023 if (CC == ISD::SETEQ && N0->getOpcode() == ISD::AND &&
7024 N0->getValueType(0) == VT &&
7025 N1C && N1C->isNullValue() &&
7026 N2C && N2C->isNullValue()) {
7027 SDValue AndLHS = N0->getOperand(0);
7028 ConstantSDNode *ConstAndRHS = dyn_cast<ConstantSDNode>(N0->getOperand(1));
7029 if (ConstAndRHS && ConstAndRHS->getAPIntValue().countPopulation() == 1) {
7030 // Shift the tested bit over the sign bit.
7031 APInt AndMask = ConstAndRHS->getAPIntValue();
7033 DAG.getConstant(AndMask.countLeadingZeros(), getShiftAmountTy());
7034 SDValue Shl = DAG.getNode(ISD::SHL, N0.getDebugLoc(), VT, AndLHS, ShlAmt);
7036 // Now arithmetic right shift it all the way over, so the result is either
7037 // all-ones, or zero.
7039 DAG.getConstant(AndMask.getBitWidth()-1, getShiftAmountTy());
7040 SDValue Shr = DAG.getNode(ISD::SRA, N0.getDebugLoc(), VT, Shl, ShrAmt);
7042 return DAG.getNode(ISD::AND, DL, VT, Shr, N3);
7046 // fold select C, 16, 0 -> shl C, 4
7047 if (N2C && N3C && N3C->isNullValue() && N2C->getAPIntValue().isPowerOf2() &&
7048 TLI.getBooleanContents() == TargetLowering::ZeroOrOneBooleanContent) {
7050 // If the caller doesn't want us to simplify this into a zext of a compare,
7052 if (NotExtCompare && N2C->getAPIntValue() == 1)
7055 // Get a SetCC of the condition
7056 // FIXME: Should probably make sure that setcc is legal if we ever have a
7057 // target where it isn't.
7059 // cast from setcc result type to select result type
7061 SCC = DAG.getSetCC(DL, TLI.getSetCCResultType(N0.getValueType()),
7063 if (N2.getValueType().bitsLT(SCC.getValueType()))
7064 Temp = DAG.getZeroExtendInReg(SCC, N2.getDebugLoc(), N2.getValueType());
7066 Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getDebugLoc(),
7067 N2.getValueType(), SCC);
7069 SCC = DAG.getSetCC(N0.getDebugLoc(), MVT::i1, N0, N1, CC);
7070 Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getDebugLoc(),
7071 N2.getValueType(), SCC);
7074 AddToWorkList(SCC.getNode());
7075 AddToWorkList(Temp.getNode());
7077 if (N2C->getAPIntValue() == 1)
7080 // shl setcc result by log2 n2c
7081 return DAG.getNode(ISD::SHL, DL, N2.getValueType(), Temp,
7082 DAG.getConstant(N2C->getAPIntValue().logBase2(),
7083 getShiftAmountTy()));
7086 // Check to see if this is the equivalent of setcc
7087 // FIXME: Turn all of these into setcc if setcc if setcc is legal
7088 // otherwise, go ahead with the folds.
7089 if (0 && N3C && N3C->isNullValue() && N2C && (N2C->getAPIntValue() == 1ULL)) {
7090 EVT XType = N0.getValueType();
7091 if (!LegalOperations ||
7092 TLI.isOperationLegal(ISD::SETCC, TLI.getSetCCResultType(XType))) {
7093 SDValue Res = DAG.getSetCC(DL, TLI.getSetCCResultType(XType), N0, N1, CC);
7094 if (Res.getValueType() != VT)
7095 Res = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, Res);
7099 // fold (seteq X, 0) -> (srl (ctlz X, log2(size(X))))
7100 if (N1C && N1C->isNullValue() && CC == ISD::SETEQ &&
7101 (!LegalOperations ||
7102 TLI.isOperationLegal(ISD::CTLZ, XType))) {
7103 SDValue Ctlz = DAG.getNode(ISD::CTLZ, N0.getDebugLoc(), XType, N0);
7104 return DAG.getNode(ISD::SRL, DL, XType, Ctlz,
7105 DAG.getConstant(Log2_32(XType.getSizeInBits()),
7106 getShiftAmountTy()));
7108 // fold (setgt X, 0) -> (srl (and (-X, ~X), size(X)-1))
7109 if (N1C && N1C->isNullValue() && CC == ISD::SETGT) {
7110 SDValue NegN0 = DAG.getNode(ISD::SUB, N0.getDebugLoc(),
7111 XType, DAG.getConstant(0, XType), N0);
7112 SDValue NotN0 = DAG.getNOT(N0.getDebugLoc(), N0, XType);
7113 return DAG.getNode(ISD::SRL, DL, XType,
7114 DAG.getNode(ISD::AND, DL, XType, NegN0, NotN0),
7115 DAG.getConstant(XType.getSizeInBits()-1,
7116 getShiftAmountTy()));
7118 // fold (setgt X, -1) -> (xor (srl (X, size(X)-1), 1))
7119 if (N1C && N1C->isAllOnesValue() && CC == ISD::SETGT) {
7120 SDValue Sign = DAG.getNode(ISD::SRL, N0.getDebugLoc(), XType, N0,
7121 DAG.getConstant(XType.getSizeInBits()-1,
7122 getShiftAmountTy()));
7123 return DAG.getNode(ISD::XOR, DL, XType, Sign, DAG.getConstant(1, XType));
7127 // Check to see if this is an integer abs.
7128 // select_cc setg[te] X, 0, X, -X ->
7129 // select_cc setgt X, -1, X, -X ->
7130 // select_cc setl[te] X, 0, -X, X ->
7131 // select_cc setlt X, 1, -X, X ->
7132 // Y = sra (X, size(X)-1); xor (add (X, Y), Y)
7134 ConstantSDNode *SubC = NULL;
7135 if (((N1C->isNullValue() && (CC == ISD::SETGT || CC == ISD::SETGE)) ||
7136 (N1C->isAllOnesValue() && CC == ISD::SETGT)) &&
7137 N0 == N2 && N3.getOpcode() == ISD::SUB && N0 == N3.getOperand(1))
7138 SubC = dyn_cast<ConstantSDNode>(N3.getOperand(0));
7139 else if (((N1C->isNullValue() && (CC == ISD::SETLT || CC == ISD::SETLE)) ||
7140 (N1C->isOne() && CC == ISD::SETLT)) &&
7141 N0 == N3 && N2.getOpcode() == ISD::SUB && N0 == N2.getOperand(1))
7142 SubC = dyn_cast<ConstantSDNode>(N2.getOperand(0));
7144 EVT XType = N0.getValueType();
7145 if (SubC && SubC->isNullValue() && XType.isInteger()) {
7146 SDValue Shift = DAG.getNode(ISD::SRA, N0.getDebugLoc(), XType,
7148 DAG.getConstant(XType.getSizeInBits()-1,
7149 getShiftAmountTy()));
7150 SDValue Add = DAG.getNode(ISD::ADD, N0.getDebugLoc(),
7152 AddToWorkList(Shift.getNode());
7153 AddToWorkList(Add.getNode());
7154 return DAG.getNode(ISD::XOR, DL, XType, Add, Shift);
7161 /// SimplifySetCC - This is a stub for TargetLowering::SimplifySetCC.
7162 SDValue DAGCombiner::SimplifySetCC(EVT VT, SDValue N0,
7163 SDValue N1, ISD::CondCode Cond,
7164 DebugLoc DL, bool foldBooleans) {
7165 TargetLowering::DAGCombinerInfo
7166 DagCombineInfo(DAG, !LegalTypes, !LegalOperations, false, this);
7167 return TLI.SimplifySetCC(VT, N0, N1, Cond, foldBooleans, DagCombineInfo, DL);
7170 /// BuildSDIVSequence - Given an ISD::SDIV node expressing a divide by constant,
7171 /// return a DAG expression to select that will generate the same value by
7172 /// multiplying by a magic number. See:
7173 /// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
7174 SDValue DAGCombiner::BuildSDIV(SDNode *N) {
7175 std::vector<SDNode*> Built;
7176 SDValue S = TLI.BuildSDIV(N, DAG, &Built);
7178 for (std::vector<SDNode*>::iterator ii = Built.begin(), ee = Built.end();
7184 /// BuildUDIVSequence - Given an ISD::UDIV node expressing a divide by constant,
7185 /// return a DAG expression to select that will generate the same value by
7186 /// multiplying by a magic number. See:
7187 /// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
7188 SDValue DAGCombiner::BuildUDIV(SDNode *N) {
7189 std::vector<SDNode*> Built;
7190 SDValue S = TLI.BuildUDIV(N, DAG, &Built);
7192 for (std::vector<SDNode*>::iterator ii = Built.begin(), ee = Built.end();
7198 /// FindBaseOffset - Return true if base is a frame index, which is known not
7199 // to alias with anything but itself. Provides base object and offset as
7201 static bool FindBaseOffset(SDValue Ptr, SDValue &Base, int64_t &Offset,
7202 const GlobalValue *&GV, void *&CV) {
7203 // Assume it is a primitive operation.
7204 Base = Ptr; Offset = 0; GV = 0; CV = 0;
7206 // If it's an adding a simple constant then integrate the offset.
7207 if (Base.getOpcode() == ISD::ADD) {
7208 if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Base.getOperand(1))) {
7209 Base = Base.getOperand(0);
7210 Offset += C->getZExtValue();
7214 // Return the underlying GlobalValue, and update the Offset. Return false
7215 // for GlobalAddressSDNode since the same GlobalAddress may be represented
7216 // by multiple nodes with different offsets.
7217 if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Base)) {
7218 GV = G->getGlobal();
7219 Offset += G->getOffset();
7223 // Return the underlying Constant value, and update the Offset. Return false
7224 // for ConstantSDNodes since the same constant pool entry may be represented
7225 // by multiple nodes with different offsets.
7226 if (ConstantPoolSDNode *C = dyn_cast<ConstantPoolSDNode>(Base)) {
7227 CV = C->isMachineConstantPoolEntry() ? (void *)C->getMachineCPVal()
7228 : (void *)C->getConstVal();
7229 Offset += C->getOffset();
7232 // If it's any of the following then it can't alias with anything but itself.
7233 return isa<FrameIndexSDNode>(Base);
7236 /// isAlias - Return true if there is any possibility that the two addresses
7238 bool DAGCombiner::isAlias(SDValue Ptr1, int64_t Size1,
7239 const Value *SrcValue1, int SrcValueOffset1,
7240 unsigned SrcValueAlign1,
7241 const MDNode *TBAAInfo1,
7242 SDValue Ptr2, int64_t Size2,
7243 const Value *SrcValue2, int SrcValueOffset2,
7244 unsigned SrcValueAlign2,
7245 const MDNode *TBAAInfo2) const {
7246 // If they are the same then they must be aliases.
7247 if (Ptr1 == Ptr2) return true;
7249 // Gather base node and offset information.
7250 SDValue Base1, Base2;
7251 int64_t Offset1, Offset2;
7252 const GlobalValue *GV1, *GV2;
7254 bool isFrameIndex1 = FindBaseOffset(Ptr1, Base1, Offset1, GV1, CV1);
7255 bool isFrameIndex2 = FindBaseOffset(Ptr2, Base2, Offset2, GV2, CV2);
7257 // If they have a same base address then check to see if they overlap.
7258 if (Base1 == Base2 || (GV1 && (GV1 == GV2)) || (CV1 && (CV1 == CV2)))
7259 return !((Offset1 + Size1) <= Offset2 || (Offset2 + Size2) <= Offset1);
7261 // It is possible for different frame indices to alias each other, mostly
7262 // when tail call optimization reuses return address slots for arguments.
7263 // To catch this case, look up the actual index of frame indices to compute
7264 // the real alias relationship.
7265 if (isFrameIndex1 && isFrameIndex2) {
7266 MachineFrameInfo *MFI = DAG.getMachineFunction().getFrameInfo();
7267 Offset1 += MFI->getObjectOffset(cast<FrameIndexSDNode>(Base1)->getIndex());
7268 Offset2 += MFI->getObjectOffset(cast<FrameIndexSDNode>(Base2)->getIndex());
7269 return !((Offset1 + Size1) <= Offset2 || (Offset2 + Size2) <= Offset1);
7272 // Otherwise, if we know what the bases are, and they aren't identical, then
7273 // we know they cannot alias.
7274 if ((isFrameIndex1 || CV1 || GV1) && (isFrameIndex2 || CV2 || GV2))
7277 // If we know required SrcValue1 and SrcValue2 have relatively large alignment
7278 // compared to the size and offset of the access, we may be able to prove they
7279 // do not alias. This check is conservative for now to catch cases created by
7280 // splitting vector types.
7281 if ((SrcValueAlign1 == SrcValueAlign2) &&
7282 (SrcValueOffset1 != SrcValueOffset2) &&
7283 (Size1 == Size2) && (SrcValueAlign1 > Size1)) {
7284 int64_t OffAlign1 = SrcValueOffset1 % SrcValueAlign1;
7285 int64_t OffAlign2 = SrcValueOffset2 % SrcValueAlign1;
7287 // There is no overlap between these relatively aligned accesses of similar
7288 // size, return no alias.
7289 if ((OffAlign1 + Size1) <= OffAlign2 || (OffAlign2 + Size2) <= OffAlign1)
7293 if (CombinerGlobalAA) {
7294 // Use alias analysis information.
7295 int64_t MinOffset = std::min(SrcValueOffset1, SrcValueOffset2);
7296 int64_t Overlap1 = Size1 + SrcValueOffset1 - MinOffset;
7297 int64_t Overlap2 = Size2 + SrcValueOffset2 - MinOffset;
7298 AliasAnalysis::AliasResult AAResult =
7299 AA.alias(AliasAnalysis::Location(SrcValue1, Overlap1, TBAAInfo1),
7300 AliasAnalysis::Location(SrcValue2, Overlap2, TBAAInfo2));
7301 if (AAResult == AliasAnalysis::NoAlias)
7305 // Otherwise we have to assume they alias.
7309 /// FindAliasInfo - Extracts the relevant alias information from the memory
7310 /// node. Returns true if the operand was a load.
7311 bool DAGCombiner::FindAliasInfo(SDNode *N,
7312 SDValue &Ptr, int64_t &Size,
7313 const Value *&SrcValue,
7314 int &SrcValueOffset,
7315 unsigned &SrcValueAlign,
7316 const MDNode *&TBAAInfo) const {
7317 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) {
7318 Ptr = LD->getBasePtr();
7319 Size = LD->getMemoryVT().getSizeInBits() >> 3;
7320 SrcValue = LD->getSrcValue();
7321 SrcValueOffset = LD->getSrcValueOffset();
7322 SrcValueAlign = LD->getOriginalAlignment();
7323 TBAAInfo = LD->getTBAAInfo();
7325 } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) {
7326 Ptr = ST->getBasePtr();
7327 Size = ST->getMemoryVT().getSizeInBits() >> 3;
7328 SrcValue = ST->getSrcValue();
7329 SrcValueOffset = ST->getSrcValueOffset();
7330 SrcValueAlign = ST->getOriginalAlignment();
7331 TBAAInfo = ST->getTBAAInfo();
7333 llvm_unreachable("FindAliasInfo expected a memory operand");
7339 /// GatherAllAliases - Walk up chain skipping non-aliasing memory nodes,
7340 /// looking for aliasing nodes and adding them to the Aliases vector.
7341 void DAGCombiner::GatherAllAliases(SDNode *N, SDValue OriginalChain,
7342 SmallVector<SDValue, 8> &Aliases) {
7343 SmallVector<SDValue, 8> Chains; // List of chains to visit.
7344 SmallPtrSet<SDNode *, 16> Visited; // Visited node set.
7346 // Get alias information for node.
7349 const Value *SrcValue;
7351 unsigned SrcValueAlign;
7352 const MDNode *SrcTBAAInfo;
7353 bool IsLoad = FindAliasInfo(N, Ptr, Size, SrcValue, SrcValueOffset,
7354 SrcValueAlign, SrcTBAAInfo);
7357 Chains.push_back(OriginalChain);
7360 // Look at each chain and determine if it is an alias. If so, add it to the
7361 // aliases list. If not, then continue up the chain looking for the next
7363 while (!Chains.empty()) {
7364 SDValue Chain = Chains.back();
7367 // For TokenFactor nodes, look at each operand and only continue up the
7368 // chain until we find two aliases. If we've seen two aliases, assume we'll
7369 // find more and revert to original chain since the xform is unlikely to be
7372 // FIXME: The depth check could be made to return the last non-aliasing
7373 // chain we found before we hit a tokenfactor rather than the original
7375 if (Depth > 6 || Aliases.size() == 2) {
7377 Aliases.push_back(OriginalChain);
7381 // Don't bother if we've been before.
7382 if (!Visited.insert(Chain.getNode()))
7385 switch (Chain.getOpcode()) {
7386 case ISD::EntryToken:
7387 // Entry token is ideal chain operand, but handled in FindBetterChain.
7392 // Get alias information for Chain.
7395 const Value *OpSrcValue;
7396 int OpSrcValueOffset;
7397 unsigned OpSrcValueAlign;
7398 const MDNode *OpSrcTBAAInfo;
7399 bool IsOpLoad = FindAliasInfo(Chain.getNode(), OpPtr, OpSize,
7400 OpSrcValue, OpSrcValueOffset,
7404 // If chain is alias then stop here.
7405 if (!(IsLoad && IsOpLoad) &&
7406 isAlias(Ptr, Size, SrcValue, SrcValueOffset, SrcValueAlign,
7408 OpPtr, OpSize, OpSrcValue, OpSrcValueOffset,
7409 OpSrcValueAlign, OpSrcTBAAInfo)) {
7410 Aliases.push_back(Chain);
7412 // Look further up the chain.
7413 Chains.push_back(Chain.getOperand(0));
7419 case ISD::TokenFactor:
7420 // We have to check each of the operands of the token factor for "small"
7421 // token factors, so we queue them up. Adding the operands to the queue
7422 // (stack) in reverse order maintains the original order and increases the
7423 // likelihood that getNode will find a matching token factor (CSE.)
7424 if (Chain.getNumOperands() > 16) {
7425 Aliases.push_back(Chain);
7428 for (unsigned n = Chain.getNumOperands(); n;)
7429 Chains.push_back(Chain.getOperand(--n));
7434 // For all other instructions we will just have to take what we can get.
7435 Aliases.push_back(Chain);
7441 /// FindBetterChain - Walk up chain skipping non-aliasing memory nodes, looking
7442 /// for a better chain (aliasing node.)
7443 SDValue DAGCombiner::FindBetterChain(SDNode *N, SDValue OldChain) {
7444 SmallVector<SDValue, 8> Aliases; // Ops for replacing token factor.
7446 // Accumulate all the aliases to this node.
7447 GatherAllAliases(N, OldChain, Aliases);
7449 if (Aliases.size() == 0) {
7450 // If no operands then chain to entry token.
7451 return DAG.getEntryNode();
7452 } else if (Aliases.size() == 1) {
7453 // If a single operand then chain to it. We don't need to revisit it.
7457 // Construct a custom tailored token factor.
7458 return DAG.getNode(ISD::TokenFactor, N->getDebugLoc(), MVT::Other,
7459 &Aliases[0], Aliases.size());
7462 // SelectionDAG::Combine - This is the entry point for the file.
7464 void SelectionDAG::Combine(CombineLevel Level, AliasAnalysis &AA,
7465 CodeGenOpt::Level OptLevel) {
7466 /// run - This is the main entry point to this class.
7468 DAGCombiner(*this, AA, OptLevel).Run(Level);