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 //===----------------------------------------------------------------------===//
15 #define DEBUG_TYPE "dagcombine"
16 #include "llvm/CodeGen/SelectionDAG.h"
17 #include "llvm/CodeGen/MachineFunction.h"
18 #include "llvm/CodeGen/MachineFrameInfo.h"
19 #include "llvm/Analysis/AliasAnalysis.h"
20 #include "llvm/Target/TargetData.h"
21 #include "llvm/Target/TargetFrameInfo.h"
22 #include "llvm/Target/TargetLowering.h"
23 #include "llvm/Target/TargetMachine.h"
24 #include "llvm/Target/TargetOptions.h"
25 #include "llvm/ADT/SmallPtrSet.h"
26 #include "llvm/ADT/Statistic.h"
27 #include "llvm/Support/Compiler.h"
28 #include "llvm/Support/CommandLine.h"
29 #include "llvm/Support/Debug.h"
30 #include "llvm/Support/MathExtras.h"
35 STATISTIC(NodesCombined , "Number of dag nodes combined");
36 STATISTIC(PreIndexedNodes , "Number of pre-indexed nodes created");
37 STATISTIC(PostIndexedNodes, "Number of post-indexed nodes created");
41 CombinerAA("combiner-alias-analysis", cl::Hidden,
42 cl::desc("Turn on alias analysis during testing"));
45 CombinerGlobalAA("combiner-global-alias-analysis", cl::Hidden,
46 cl::desc("Include global information in alias analysis"));
48 //------------------------------ DAGCombiner ---------------------------------//
50 class VISIBILITY_HIDDEN DAGCombiner {
52 const TargetLowering &TLI;
58 // Worklist of all of the nodes that need to be simplified.
59 std::vector<SDNode*> WorkList;
61 // AA - Used for DAG load/store alias analysis.
64 /// AddUsersToWorkList - When an instruction is simplified, add all users of
65 /// the instruction to the work lists because they might get more simplified
68 void AddUsersToWorkList(SDNode *N) {
69 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end();
74 /// visit - call the node-specific routine that knows how to fold each
75 /// particular type of node.
76 SDValue visit(SDNode *N);
79 /// AddToWorkList - Add to the work list making sure it's instance is at the
80 /// the back (next to be processed.)
81 void AddToWorkList(SDNode *N) {
82 removeFromWorkList(N);
83 WorkList.push_back(N);
86 /// removeFromWorkList - remove all instances of N from the worklist.
88 void removeFromWorkList(SDNode *N) {
89 WorkList.erase(std::remove(WorkList.begin(), WorkList.end(), N),
93 SDValue CombineTo(SDNode *N, const SDValue *To, unsigned NumTo,
96 SDValue CombineTo(SDNode *N, SDValue Res, bool AddTo = true) {
97 return CombineTo(N, &Res, 1, AddTo);
100 SDValue CombineTo(SDNode *N, SDValue Res0, SDValue Res1,
102 SDValue To[] = { Res0, Res1 };
103 return CombineTo(N, To, 2, AddTo);
106 void CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO);
110 /// SimplifyDemandedBits - Check the specified integer node value to see if
111 /// it can be simplified or if things it uses can be simplified by bit
112 /// propagation. If so, return true.
113 bool SimplifyDemandedBits(SDValue Op) {
114 APInt Demanded = APInt::getAllOnesValue(Op.getValueSizeInBits());
115 return SimplifyDemandedBits(Op, Demanded);
118 bool SimplifyDemandedBits(SDValue Op, const APInt &Demanded);
120 bool CombineToPreIndexedLoadStore(SDNode *N);
121 bool CombineToPostIndexedLoadStore(SDNode *N);
124 /// combine - call the node-specific routine that knows how to fold each
125 /// particular type of node. If that doesn't do anything, try the
126 /// target-specific DAG combines.
127 SDValue combine(SDNode *N);
129 // Visitation implementation - Implement dag node combining for different
130 // node types. The semantics are as follows:
132 // SDValue.getNode() == 0 - No change was made
133 // SDValue.getNode() == N - N was replaced, is dead and has been handled.
134 // otherwise - N should be replaced by the returned Operand.
136 SDValue visitTokenFactor(SDNode *N);
137 SDValue visitMERGE_VALUES(SDNode *N);
138 SDValue visitADD(SDNode *N);
139 SDValue visitSUB(SDNode *N);
140 SDValue visitADDC(SDNode *N);
141 SDValue visitADDE(SDNode *N);
142 SDValue visitMUL(SDNode *N);
143 SDValue visitSDIV(SDNode *N);
144 SDValue visitUDIV(SDNode *N);
145 SDValue visitSREM(SDNode *N);
146 SDValue visitUREM(SDNode *N);
147 SDValue visitMULHU(SDNode *N);
148 SDValue visitMULHS(SDNode *N);
149 SDValue visitSMUL_LOHI(SDNode *N);
150 SDValue visitUMUL_LOHI(SDNode *N);
151 SDValue visitSDIVREM(SDNode *N);
152 SDValue visitUDIVREM(SDNode *N);
153 SDValue visitAND(SDNode *N);
154 SDValue visitOR(SDNode *N);
155 SDValue visitXOR(SDNode *N);
156 SDValue SimplifyVBinOp(SDNode *N);
157 SDValue visitSHL(SDNode *N);
158 SDValue visitSRA(SDNode *N);
159 SDValue visitSRL(SDNode *N);
160 SDValue visitCTLZ(SDNode *N);
161 SDValue visitCTTZ(SDNode *N);
162 SDValue visitCTPOP(SDNode *N);
163 SDValue visitSELECT(SDNode *N);
164 SDValue visitSELECT_CC(SDNode *N);
165 SDValue visitSETCC(SDNode *N);
166 SDValue visitSIGN_EXTEND(SDNode *N);
167 SDValue visitZERO_EXTEND(SDNode *N);
168 SDValue visitANY_EXTEND(SDNode *N);
169 SDValue visitSIGN_EXTEND_INREG(SDNode *N);
170 SDValue visitTRUNCATE(SDNode *N);
171 SDValue visitBIT_CONVERT(SDNode *N);
172 SDValue visitBUILD_PAIR(SDNode *N);
173 SDValue visitFADD(SDNode *N);
174 SDValue visitFSUB(SDNode *N);
175 SDValue visitFMUL(SDNode *N);
176 SDValue visitFDIV(SDNode *N);
177 SDValue visitFREM(SDNode *N);
178 SDValue visitFCOPYSIGN(SDNode *N);
179 SDValue visitSINT_TO_FP(SDNode *N);
180 SDValue visitUINT_TO_FP(SDNode *N);
181 SDValue visitFP_TO_SINT(SDNode *N);
182 SDValue visitFP_TO_UINT(SDNode *N);
183 SDValue visitFP_ROUND(SDNode *N);
184 SDValue visitFP_ROUND_INREG(SDNode *N);
185 SDValue visitFP_EXTEND(SDNode *N);
186 SDValue visitFNEG(SDNode *N);
187 SDValue visitFABS(SDNode *N);
188 SDValue visitBRCOND(SDNode *N);
189 SDValue visitBR_CC(SDNode *N);
190 SDValue visitLOAD(SDNode *N);
191 SDValue visitSTORE(SDNode *N);
192 SDValue visitINSERT_VECTOR_ELT(SDNode *N);
193 SDValue visitEXTRACT_VECTOR_ELT(SDNode *N);
194 SDValue visitBUILD_VECTOR(SDNode *N);
195 SDValue visitCONCAT_VECTORS(SDNode *N);
196 SDValue visitVECTOR_SHUFFLE(SDNode *N);
198 SDValue XformToShuffleWithZero(SDNode *N);
199 SDValue ReassociateOps(unsigned Opc, DebugLoc DL, SDValue LHS, SDValue RHS);
201 SDValue visitShiftByConstant(SDNode *N, unsigned Amt);
203 bool SimplifySelectOps(SDNode *SELECT, SDValue LHS, SDValue RHS);
204 SDValue SimplifyBinOpWithSameOpcodeHands(SDNode *N);
205 SDValue SimplifySelect(SDValue N0, SDValue N1, SDValue N2);
206 SDValue SimplifySelectCC(SDValue N0, SDValue N1, SDValue N2,
207 SDValue N3, ISD::CondCode CC,
208 bool NotExtCompare = false);
209 SDValue SimplifySetCC(MVT VT, SDValue N0, SDValue N1, ISD::CondCode Cond,
210 bool foldBooleans = true);
211 SDValue SimplifyNodeWithTwoResults(SDNode *N, unsigned LoOp,
213 SDValue CombineConsecutiveLoads(SDNode *N, MVT VT);
214 SDValue ConstantFoldBIT_CONVERTofBUILD_VECTOR(SDNode *, MVT);
215 SDValue BuildSDIV(SDNode *N);
216 SDValue BuildUDIV(SDNode *N);
217 SDNode *MatchRotate(SDValue LHS, SDValue RHS);
218 SDValue ReduceLoadWidth(SDNode *N);
220 SDValue GetDemandedBits(SDValue V, const APInt &Mask);
222 /// GatherAllAliases - Walk up chain skipping non-aliasing memory nodes,
223 /// looking for aliasing nodes and adding them to the Aliases vector.
224 void GatherAllAliases(SDNode *N, SDValue OriginalChain,
225 SmallVector<SDValue, 8> &Aliases);
227 /// isAlias - Return true if there is any possibility that the two addresses
229 bool isAlias(SDValue Ptr1, int64_t Size1,
230 const Value *SrcValue1, int SrcValueOffset1,
231 SDValue Ptr2, int64_t Size2,
232 const Value *SrcValue2, int SrcValueOffset2);
234 /// FindAliasInfo - Extracts the relevant alias information from the memory
235 /// node. Returns true if the operand was a load.
236 bool FindAliasInfo(SDNode *N,
237 SDValue &Ptr, int64_t &Size,
238 const Value *&SrcValue, int &SrcValueOffset);
240 /// FindBetterChain - Walk up chain skipping non-aliasing memory nodes,
241 /// looking for a better chain (aliasing node.)
242 SDValue FindBetterChain(SDNode *N, SDValue Chain);
245 DAGCombiner(SelectionDAG &D, AliasAnalysis &A, bool fast)
247 TLI(D.getTargetLoweringInfo()),
249 LegalOperations(false),
254 /// Run - runs the dag combiner on all nodes in the work list
255 void Run(CombineLevel AtLevel);
261 /// WorkListRemover - This class is a DAGUpdateListener that removes any deleted
262 /// nodes from the worklist.
263 class VISIBILITY_HIDDEN WorkListRemover :
264 public SelectionDAG::DAGUpdateListener {
267 explicit WorkListRemover(DAGCombiner &dc) : DC(dc) {}
269 virtual void NodeDeleted(SDNode *N, SDNode *E) {
270 DC.removeFromWorkList(N);
273 virtual void NodeUpdated(SDNode *N) {
279 //===----------------------------------------------------------------------===//
280 // TargetLowering::DAGCombinerInfo implementation
281 //===----------------------------------------------------------------------===//
283 void TargetLowering::DAGCombinerInfo::AddToWorklist(SDNode *N) {
284 ((DAGCombiner*)DC)->AddToWorkList(N);
287 SDValue TargetLowering::DAGCombinerInfo::
288 CombineTo(SDNode *N, const std::vector<SDValue> &To) {
289 return ((DAGCombiner*)DC)->CombineTo(N, &To[0], To.size());
292 SDValue TargetLowering::DAGCombinerInfo::
293 CombineTo(SDNode *N, SDValue Res) {
294 return ((DAGCombiner*)DC)->CombineTo(N, Res);
298 SDValue TargetLowering::DAGCombinerInfo::
299 CombineTo(SDNode *N, SDValue Res0, SDValue Res1) {
300 return ((DAGCombiner*)DC)->CombineTo(N, Res0, Res1);
303 void TargetLowering::DAGCombinerInfo::
304 CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO) {
305 return ((DAGCombiner*)DC)->CommitTargetLoweringOpt(TLO);
308 //===----------------------------------------------------------------------===//
310 //===----------------------------------------------------------------------===//
312 /// isNegatibleForFree - Return 1 if we can compute the negated form of the
313 /// specified expression for the same cost as the expression itself, or 2 if we
314 /// can compute the negated form more cheaply than the expression itself.
315 static char isNegatibleForFree(SDValue Op, bool LegalOperations,
316 unsigned Depth = 0) {
317 // No compile time optimizations on this type.
318 if (Op.getValueType() == MVT::ppcf128)
321 // fneg is removable even if it has multiple uses.
322 if (Op.getOpcode() == ISD::FNEG) return 2;
324 // Don't allow anything with multiple uses.
325 if (!Op.hasOneUse()) return 0;
327 // Don't recurse exponentially.
328 if (Depth > 6) return 0;
330 switch (Op.getOpcode()) {
331 default: return false;
332 case ISD::ConstantFP:
333 // Don't invert constant FP values after legalize. The negated constant
334 // isn't necessarily legal.
335 return LegalOperations ? 0 : 1;
337 // FIXME: determine better conditions for this xform.
338 if (!UnsafeFPMath) return 0;
341 if (char V = isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1))
344 return isNegatibleForFree(Op.getOperand(1), LegalOperations, Depth+1);
346 // We can't turn -(A-B) into B-A when we honor signed zeros.
347 if (!UnsafeFPMath) return 0;
354 if (HonorSignDependentRoundingFPMath()) return 0;
356 // -(X*Y) -> (-X * Y) or (X*-Y)
357 if (char V = isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1))
360 return isNegatibleForFree(Op.getOperand(1), LegalOperations, Depth+1);
365 return isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1);
369 /// GetNegatedExpression - If isNegatibleForFree returns true, this function
370 /// returns the newly negated expression.
371 static SDValue GetNegatedExpression(SDValue Op, SelectionDAG &DAG,
372 bool LegalOperations, unsigned Depth = 0) {
373 // fneg is removable even if it has multiple uses.
374 if (Op.getOpcode() == ISD::FNEG) return Op.getOperand(0);
376 // Don't allow anything with multiple uses.
377 assert(Op.hasOneUse() && "Unknown reuse!");
379 assert(Depth <= 6 && "GetNegatedExpression doesn't match isNegatibleForFree");
380 switch (Op.getOpcode()) {
381 default: assert(0 && "Unknown code");
382 case ISD::ConstantFP: {
383 APFloat V = cast<ConstantFPSDNode>(Op)->getValueAPF();
385 return DAG.getConstantFP(V, Op.getValueType());
388 // FIXME: determine better conditions for this xform.
389 assert(UnsafeFPMath);
392 if (isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1))
393 return DAG.getNode(ISD::FSUB, Op.getDebugLoc(), Op.getValueType(),
394 GetNegatedExpression(Op.getOperand(0), DAG,
395 LegalOperations, Depth+1),
398 return DAG.getNode(ISD::FSUB, Op.getDebugLoc(), Op.getValueType(),
399 GetNegatedExpression(Op.getOperand(1), DAG,
400 LegalOperations, Depth+1),
403 // We can't turn -(A-B) into B-A when we honor signed zeros.
404 assert(UnsafeFPMath);
407 if (ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(Op.getOperand(0)))
408 if (N0CFP->getValueAPF().isZero())
409 return Op.getOperand(1);
412 return DAG.getNode(ISD::FSUB, Op.getDebugLoc(), Op.getValueType(),
413 Op.getOperand(1), Op.getOperand(0));
417 assert(!HonorSignDependentRoundingFPMath());
420 if (isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1))
421 return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), Op.getValueType(),
422 GetNegatedExpression(Op.getOperand(0), DAG,
423 LegalOperations, Depth+1),
427 return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), Op.getValueType(),
429 GetNegatedExpression(Op.getOperand(1), DAG,
430 LegalOperations, Depth+1));
434 return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), Op.getValueType(),
435 GetNegatedExpression(Op.getOperand(0), DAG,
436 LegalOperations, Depth+1));
438 return DAG.getNode(ISD::FP_ROUND, Op.getDebugLoc(), Op.getValueType(),
439 GetNegatedExpression(Op.getOperand(0), DAG,
440 LegalOperations, Depth+1),
446 // isSetCCEquivalent - Return true if this node is a setcc, or is a select_cc
447 // that selects between the values 1 and 0, making it equivalent to a setcc.
448 // Also, set the incoming LHS, RHS, and CC references to the appropriate
449 // nodes based on the type of node we are checking. This simplifies life a
450 // bit for the callers.
451 static bool isSetCCEquivalent(SDValue N, SDValue &LHS, SDValue &RHS,
453 if (N.getOpcode() == ISD::SETCC) {
454 LHS = N.getOperand(0);
455 RHS = N.getOperand(1);
456 CC = N.getOperand(2);
459 if (N.getOpcode() == ISD::SELECT_CC &&
460 N.getOperand(2).getOpcode() == ISD::Constant &&
461 N.getOperand(3).getOpcode() == ISD::Constant &&
462 cast<ConstantSDNode>(N.getOperand(2))->getAPIntValue() == 1 &&
463 cast<ConstantSDNode>(N.getOperand(3))->isNullValue()) {
464 LHS = N.getOperand(0);
465 RHS = N.getOperand(1);
466 CC = N.getOperand(4);
472 // isOneUseSetCC - Return true if this is a SetCC-equivalent operation with only
473 // one use. If this is true, it allows the users to invert the operation for
474 // free when it is profitable to do so.
475 static bool isOneUseSetCC(SDValue N) {
477 if (isSetCCEquivalent(N, N0, N1, N2) && N.getNode()->hasOneUse())
482 SDValue DAGCombiner::ReassociateOps(unsigned Opc, DebugLoc DL,
483 SDValue N0, SDValue N1) {
484 MVT VT = N0.getValueType();
485 if (N0.getOpcode() == Opc && isa<ConstantSDNode>(N0.getOperand(1))) {
486 if (isa<ConstantSDNode>(N1)) {
487 // reassoc. (op (op x, c1), c2) -> (op x, (op c1, c2))
488 SDValue OpNode = DAG.getNode(Opc, N0.getDebugLoc(), VT,
489 N0.getOperand(1), N1);
490 AddToWorkList(OpNode.getNode());
491 return DAG.getNode(Opc, DL, VT, OpNode, N0.getOperand(0));
492 } else if (N0.hasOneUse()) {
493 // reassoc. (op (op x, c1), y) -> (op (op x, y), c1) iff x+c1 has one use
494 SDValue OpNode = DAG.getNode(Opc, N0.getDebugLoc(), VT,
495 N0.getOperand(0), N1);
496 AddToWorkList(OpNode.getNode());
497 return DAG.getNode(Opc, DL, VT, OpNode, N0.getOperand(1));
501 if (N1.getOpcode() == Opc && isa<ConstantSDNode>(N1.getOperand(1))) {
502 if (isa<ConstantSDNode>(N0)) {
503 // reassoc. (op c2, (op x, c1)) -> (op x, (op c1, c2))
504 SDValue OpNode = DAG.getNode(Opc, N1.getDebugLoc(), VT,
505 N1.getOperand(1), N0);
506 AddToWorkList(OpNode.getNode());
507 return DAG.getNode(Opc, DL, VT, OpNode, N1.getOperand(0));
508 } else if (N1.hasOneUse()) {
509 // reassoc. (op y, (op x, c1)) -> (op (op x, y), c1) iff x+c1 has one use
510 SDValue OpNode = DAG.getNode(Opc, N1.getDebugLoc(), VT,
511 N1.getOperand(0), N0);
512 AddToWorkList(OpNode.getNode());
513 return DAG.getNode(Opc, DL, VT, OpNode, N1.getOperand(1));
520 SDValue DAGCombiner::CombineTo(SDNode *N, const SDValue *To, unsigned NumTo,
522 assert(N->getNumValues() == NumTo && "Broken CombineTo call!");
524 DOUT << "\nReplacing.1 "; DEBUG(N->dump(&DAG));
525 DOUT << "\nWith: "; DEBUG(To[0].getNode()->dump(&DAG));
526 DOUT << " and " << NumTo-1 << " other values\n";
527 DEBUG(for (unsigned i = 0, e = NumTo; i != e; ++i)
528 assert(N->getValueType(i) == To[i].getValueType() &&
529 "Cannot combine value to value of different type!"));
530 WorkListRemover DeadNodes(*this);
531 DAG.ReplaceAllUsesWith(N, To, &DeadNodes);
534 // Push the new nodes and any users onto the worklist
535 for (unsigned i = 0, e = NumTo; i != e; ++i) {
536 AddToWorkList(To[i].getNode());
537 AddUsersToWorkList(To[i].getNode());
541 // Finally, if the node is now dead, remove it from the graph. The node
542 // may not be dead if the replacement process recursively simplified to
543 // something else needing this node.
544 if (N->use_empty()) {
545 // Nodes can be reintroduced into the worklist. Make sure we do not
546 // process a node that has been replaced.
547 removeFromWorkList(N);
549 // Finally, since the node is now dead, remove it from the graph.
552 return SDValue(N, 0);
556 DAGCombiner::CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &
558 // Replace all uses. If any nodes become isomorphic to other nodes and
559 // are deleted, make sure to remove them from our worklist.
560 WorkListRemover DeadNodes(*this);
561 DAG.ReplaceAllUsesOfValueWith(TLO.Old, TLO.New, &DeadNodes);
563 // Push the new node and any (possibly new) users onto the worklist.
564 AddToWorkList(TLO.New.getNode());
565 AddUsersToWorkList(TLO.New.getNode());
567 // Finally, if the node is now dead, remove it from the graph. The node
568 // may not be dead if the replacement process recursively simplified to
569 // something else needing this node.
570 if (TLO.Old.getNode()->use_empty()) {
571 removeFromWorkList(TLO.Old.getNode());
573 // If the operands of this node are only used by the node, they will now
574 // be dead. Make sure to visit them first to delete dead nodes early.
575 for (unsigned i = 0, e = TLO.Old.getNode()->getNumOperands(); i != e; ++i)
576 if (TLO.Old.getNode()->getOperand(i).getNode()->hasOneUse())
577 AddToWorkList(TLO.Old.getNode()->getOperand(i).getNode());
579 DAG.DeleteNode(TLO.Old.getNode());
583 /// SimplifyDemandedBits - Check the specified integer node value to see if
584 /// it can be simplified or if things it uses can be simplified by bit
585 /// propagation. If so, return true.
586 bool DAGCombiner::SimplifyDemandedBits(SDValue Op, const APInt &Demanded) {
587 TargetLowering::TargetLoweringOpt TLO(DAG);
588 APInt KnownZero, KnownOne;
589 if (!TLI.SimplifyDemandedBits(Op, Demanded, KnownZero, KnownOne, TLO))
593 AddToWorkList(Op.getNode());
595 // Replace the old value with the new one.
597 DOUT << "\nReplacing.2 "; DEBUG(TLO.Old.getNode()->dump(&DAG));
598 DOUT << "\nWith: "; DEBUG(TLO.New.getNode()->dump(&DAG));
601 CommitTargetLoweringOpt(TLO);
605 //===----------------------------------------------------------------------===//
606 // Main DAG Combiner implementation
607 //===----------------------------------------------------------------------===//
609 void DAGCombiner::Run(CombineLevel AtLevel) {
610 // set the instance variables, so that the various visit routines may use it.
612 LegalOperations = Level >= NoIllegalOperations;
613 LegalTypes = Level >= NoIllegalTypes;
615 // Add all the dag nodes to the worklist.
616 WorkList.reserve(DAG.allnodes_size());
617 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(),
618 E = DAG.allnodes_end(); I != E; ++I)
619 WorkList.push_back(I);
621 // Create a dummy node (which is not added to allnodes), that adds a reference
622 // to the root node, preventing it from being deleted, and tracking any
623 // changes of the root.
624 HandleSDNode Dummy(DAG.getRoot());
626 // The root of the dag may dangle to deleted nodes until the dag combiner is
627 // done. Set it to null to avoid confusion.
628 DAG.setRoot(SDValue());
630 // while the worklist isn't empty, inspect the node on the end of it and
631 // try and combine it.
632 while (!WorkList.empty()) {
633 SDNode *N = WorkList.back();
636 // If N has no uses, it is dead. Make sure to revisit all N's operands once
637 // N is deleted from the DAG, since they too may now be dead or may have a
638 // reduced number of uses, allowing other xforms.
639 if (N->use_empty() && N != &Dummy) {
640 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
641 AddToWorkList(N->getOperand(i).getNode());
647 SDValue RV = combine(N);
649 if (RV.getNode() == 0)
654 // If we get back the same node we passed in, rather than a new node or
655 // zero, we know that the node must have defined multiple values and
656 // CombineTo was used. Since CombineTo takes care of the worklist
657 // mechanics for us, we have no work to do in this case.
658 if (RV.getNode() == N)
661 assert(N->getOpcode() != ISD::DELETED_NODE &&
662 RV.getNode()->getOpcode() != ISD::DELETED_NODE &&
663 "Node was deleted but visit returned new node!");
665 DOUT << "\nReplacing.3 "; DEBUG(N->dump(&DAG));
666 DOUT << "\nWith: "; DEBUG(RV.getNode()->dump(&DAG));
668 WorkListRemover DeadNodes(*this);
669 if (N->getNumValues() == RV.getNode()->getNumValues())
670 DAG.ReplaceAllUsesWith(N, RV.getNode(), &DeadNodes);
672 assert(N->getValueType(0) == RV.getValueType() &&
673 N->getNumValues() == 1 && "Type mismatch");
675 DAG.ReplaceAllUsesWith(N, &OpV, &DeadNodes);
678 // Push the new node and any users onto the worklist
679 AddToWorkList(RV.getNode());
680 AddUsersToWorkList(RV.getNode());
682 // Add any uses of the old node to the worklist in case this node is the
683 // last one that uses them. They may become dead after this node is
685 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
686 AddToWorkList(N->getOperand(i).getNode());
688 // Finally, if the node is now dead, remove it from the graph. The node
689 // may not be dead if the replacement process recursively simplified to
690 // something else needing this node.
691 if (N->use_empty()) {
692 // Nodes can be reintroduced into the worklist. Make sure we do not
693 // process a node that has been replaced.
694 removeFromWorkList(N);
696 // Finally, since the node is now dead, remove it from the graph.
701 // If the root changed (e.g. it was a dead load, update the root).
702 DAG.setRoot(Dummy.getValue());
705 SDValue DAGCombiner::visit(SDNode *N) {
706 switch(N->getOpcode()) {
708 case ISD::TokenFactor: return visitTokenFactor(N);
709 case ISD::MERGE_VALUES: return visitMERGE_VALUES(N);
710 case ISD::ADD: return visitADD(N);
711 case ISD::SUB: return visitSUB(N);
712 case ISD::ADDC: return visitADDC(N);
713 case ISD::ADDE: return visitADDE(N);
714 case ISD::MUL: return visitMUL(N);
715 case ISD::SDIV: return visitSDIV(N);
716 case ISD::UDIV: return visitUDIV(N);
717 case ISD::SREM: return visitSREM(N);
718 case ISD::UREM: return visitUREM(N);
719 case ISD::MULHU: return visitMULHU(N);
720 case ISD::MULHS: return visitMULHS(N);
721 case ISD::SMUL_LOHI: return visitSMUL_LOHI(N);
722 case ISD::UMUL_LOHI: return visitUMUL_LOHI(N);
723 case ISD::SDIVREM: return visitSDIVREM(N);
724 case ISD::UDIVREM: return visitUDIVREM(N);
725 case ISD::AND: return visitAND(N);
726 case ISD::OR: return visitOR(N);
727 case ISD::XOR: return visitXOR(N);
728 case ISD::SHL: return visitSHL(N);
729 case ISD::SRA: return visitSRA(N);
730 case ISD::SRL: return visitSRL(N);
731 case ISD::CTLZ: return visitCTLZ(N);
732 case ISD::CTTZ: return visitCTTZ(N);
733 case ISD::CTPOP: return visitCTPOP(N);
734 case ISD::SELECT: return visitSELECT(N);
735 case ISD::SELECT_CC: return visitSELECT_CC(N);
736 case ISD::SETCC: return visitSETCC(N);
737 case ISD::SIGN_EXTEND: return visitSIGN_EXTEND(N);
738 case ISD::ZERO_EXTEND: return visitZERO_EXTEND(N);
739 case ISD::ANY_EXTEND: return visitANY_EXTEND(N);
740 case ISD::SIGN_EXTEND_INREG: return visitSIGN_EXTEND_INREG(N);
741 case ISD::TRUNCATE: return visitTRUNCATE(N);
742 case ISD::BIT_CONVERT: return visitBIT_CONVERT(N);
743 case ISD::BUILD_PAIR: return visitBUILD_PAIR(N);
744 case ISD::FADD: return visitFADD(N);
745 case ISD::FSUB: return visitFSUB(N);
746 case ISD::FMUL: return visitFMUL(N);
747 case ISD::FDIV: return visitFDIV(N);
748 case ISD::FREM: return visitFREM(N);
749 case ISD::FCOPYSIGN: return visitFCOPYSIGN(N);
750 case ISD::SINT_TO_FP: return visitSINT_TO_FP(N);
751 case ISD::UINT_TO_FP: return visitUINT_TO_FP(N);
752 case ISD::FP_TO_SINT: return visitFP_TO_SINT(N);
753 case ISD::FP_TO_UINT: return visitFP_TO_UINT(N);
754 case ISD::FP_ROUND: return visitFP_ROUND(N);
755 case ISD::FP_ROUND_INREG: return visitFP_ROUND_INREG(N);
756 case ISD::FP_EXTEND: return visitFP_EXTEND(N);
757 case ISD::FNEG: return visitFNEG(N);
758 case ISD::FABS: return visitFABS(N);
759 case ISD::BRCOND: return visitBRCOND(N);
760 case ISD::BR_CC: return visitBR_CC(N);
761 case ISD::LOAD: return visitLOAD(N);
762 case ISD::STORE: return visitSTORE(N);
763 case ISD::INSERT_VECTOR_ELT: return visitINSERT_VECTOR_ELT(N);
764 case ISD::EXTRACT_VECTOR_ELT: return visitEXTRACT_VECTOR_ELT(N);
765 case ISD::BUILD_VECTOR: return visitBUILD_VECTOR(N);
766 case ISD::CONCAT_VECTORS: return visitCONCAT_VECTORS(N);
767 case ISD::VECTOR_SHUFFLE: return visitVECTOR_SHUFFLE(N);
772 SDValue DAGCombiner::combine(SDNode *N) {
773 SDValue RV = visit(N);
775 // If nothing happened, try a target-specific DAG combine.
776 if (RV.getNode() == 0) {
777 assert(N->getOpcode() != ISD::DELETED_NODE &&
778 "Node was deleted but visit returned NULL!");
780 if (N->getOpcode() >= ISD::BUILTIN_OP_END ||
781 TLI.hasTargetDAGCombine((ISD::NodeType)N->getOpcode())) {
783 // Expose the DAG combiner to the target combiner impls.
784 TargetLowering::DAGCombinerInfo
785 DagCombineInfo(DAG, Level == Unrestricted, false, this);
787 RV = TLI.PerformDAGCombine(N, DagCombineInfo);
791 // If N is a commutative binary node, try commuting it to enable more
793 if (RV.getNode() == 0 &&
794 SelectionDAG::isCommutativeBinOp(N->getOpcode()) &&
795 N->getNumValues() == 1) {
796 SDValue N0 = N->getOperand(0);
797 SDValue N1 = N->getOperand(1);
799 // Constant operands are canonicalized to RHS.
800 if (isa<ConstantSDNode>(N0) || !isa<ConstantSDNode>(N1)) {
801 SDValue Ops[] = { N1, N0 };
802 SDNode *CSENode = DAG.getNodeIfExists(N->getOpcode(), N->getVTList(),
805 return SDValue(CSENode, 0);
812 /// getInputChainForNode - Given a node, return its input chain if it has one,
813 /// otherwise return a null sd operand.
814 static SDValue getInputChainForNode(SDNode *N) {
815 if (unsigned NumOps = N->getNumOperands()) {
816 if (N->getOperand(0).getValueType() == MVT::Other)
817 return N->getOperand(0);
818 else if (N->getOperand(NumOps-1).getValueType() == MVT::Other)
819 return N->getOperand(NumOps-1);
820 for (unsigned i = 1; i < NumOps-1; ++i)
821 if (N->getOperand(i).getValueType() == MVT::Other)
822 return N->getOperand(i);
827 SDValue DAGCombiner::visitTokenFactor(SDNode *N) {
828 // If N has two operands, where one has an input chain equal to the other,
829 // the 'other' chain is redundant.
830 if (N->getNumOperands() == 2) {
831 if (getInputChainForNode(N->getOperand(0).getNode()) == N->getOperand(1))
832 return N->getOperand(0);
833 if (getInputChainForNode(N->getOperand(1).getNode()) == N->getOperand(0))
834 return N->getOperand(1);
837 SmallVector<SDNode *, 8> TFs; // List of token factors to visit.
838 SmallVector<SDValue, 8> Ops; // Ops for replacing token factor.
839 SmallPtrSet<SDNode*, 16> SeenOps;
840 bool Changed = false; // If we should replace this token factor.
842 // Start out with this token factor.
845 // Iterate through token factors. The TFs grows when new token factors are
847 for (unsigned i = 0; i < TFs.size(); ++i) {
850 // Check each of the operands.
851 for (unsigned i = 0, ie = TF->getNumOperands(); i != ie; ++i) {
852 SDValue Op = TF->getOperand(i);
854 switch (Op.getOpcode()) {
855 case ISD::EntryToken:
856 // Entry tokens don't need to be added to the list. They are
861 case ISD::TokenFactor:
862 if ((CombinerAA || Op.hasOneUse()) &&
863 std::find(TFs.begin(), TFs.end(), Op.getNode()) == TFs.end()) {
864 // Queue up for processing.
865 TFs.push_back(Op.getNode());
866 // Clean up in case the token factor is removed.
867 AddToWorkList(Op.getNode());
874 // Only add if it isn't already in the list.
875 if (SeenOps.insert(Op.getNode()))
886 // If we've change things around then replace token factor.
889 // The entry token is the only possible outcome.
890 Result = DAG.getEntryNode();
892 // New and improved token factor.
893 Result = DAG.getNode(ISD::TokenFactor, N->getDebugLoc(),
894 MVT::Other, &Ops[0], Ops.size());
897 // Don't add users to work list.
898 return CombineTo(N, Result, false);
904 /// MERGE_VALUES can always be eliminated.
905 SDValue DAGCombiner::visitMERGE_VALUES(SDNode *N) {
906 WorkListRemover DeadNodes(*this);
907 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
908 DAG.ReplaceAllUsesOfValueWith(SDValue(N, i), N->getOperand(i),
910 removeFromWorkList(N);
912 return SDValue(N, 0); // Return N so it doesn't get rechecked!
916 SDValue combineShlAddConstant(SDValue N0, SDValue N1, SelectionDAG &DAG) {
917 MVT VT = N0.getValueType();
918 SDValue N00 = N0.getOperand(0);
919 SDValue N01 = N0.getOperand(1);
920 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N01);
921 if (N01C && N00.getOpcode() == ISD::ADD && N00.getNode()->hasOneUse() &&
922 isa<ConstantSDNode>(N00.getOperand(1))) {
923 N0 = DAG.getNode(ISD::ADD, VT,
924 DAG.getNode(ISD::SHL, VT, N00.getOperand(0), N01),
925 DAG.getNode(ISD::SHL, VT, N00.getOperand(1), N01));
926 return DAG.getNode(ISD::ADD, VT, N0, N1);
932 SDValue combineSelectAndUse(SDNode *N, SDValue Slct, SDValue OtherOp,
933 SelectionDAG &DAG, const TargetLowering &TLI,
934 bool LegalOperations) {
935 MVT VT = N->getValueType(0);
936 unsigned Opc = N->getOpcode();
937 bool isSlctCC = Slct.getOpcode() == ISD::SELECT_CC;
938 SDValue LHS = isSlctCC ? Slct.getOperand(2) : Slct.getOperand(1);
939 SDValue RHS = isSlctCC ? Slct.getOperand(3) : Slct.getOperand(2);
940 ISD::CondCode CC = ISD::SETCC_INVALID;
943 CC = cast<CondCodeSDNode>(Slct.getOperand(4))->get();
945 SDValue CCOp = Slct.getOperand(0);
946 if (CCOp.getOpcode() == ISD::SETCC)
947 CC = cast<CondCodeSDNode>(CCOp.getOperand(2))->get();
950 bool DoXform = false;
952 assert ((Opc == ISD::ADD || (Opc == ISD::SUB && Slct == N->getOperand(1))) &&
955 if (LHS.getOpcode() == ISD::Constant &&
956 cast<ConstantSDNode>(LHS)->isNullValue()) {
958 } else if (CC != ISD::SETCC_INVALID &&
959 RHS.getOpcode() == ISD::Constant &&
960 cast<ConstantSDNode>(RHS)->isNullValue()) {
962 SDValue Op0 = Slct.getOperand(0);
963 MVT OpVT = isSlctCC ? Op0.getValueType() :
964 Op0.getOperand(0).getValueType();
965 bool isInt = OpVT.isInteger();
966 CC = ISD::getSetCCInverse(CC, isInt);
968 if (LegalOperations && !TLI.isCondCodeLegal(CC, OpVT))
969 return SDValue(); // Inverse operator isn't legal.
976 SDValue Result = DAG.getNode(Opc, VT, OtherOp, RHS);
978 return DAG.getSelectCC(OtherOp, Result,
979 Slct.getOperand(0), Slct.getOperand(1), CC);
980 SDValue CCOp = Slct.getOperand(0);
982 CCOp = DAG.getSetCC(CCOp.getValueType(), CCOp.getOperand(0),
983 CCOp.getOperand(1), CC);
984 return DAG.getNode(ISD::SELECT, VT, CCOp, OtherOp, Result);
989 SDValue DAGCombiner::visitADD(SDNode *N) {
990 SDValue N0 = N->getOperand(0);
991 SDValue N1 = N->getOperand(1);
992 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
993 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
994 MVT VT = N0.getValueType();
998 SDValue FoldedVOp = SimplifyVBinOp(N);
999 if (FoldedVOp.getNode()) return FoldedVOp;
1002 // fold (add x, undef) -> undef
1003 if (N0.getOpcode() == ISD::UNDEF)
1005 if (N1.getOpcode() == ISD::UNDEF)
1007 // fold (add c1, c2) -> c1+c2
1009 return DAG.FoldConstantArithmetic(ISD::ADD, VT, N0C, N1C);
1010 // canonicalize constant to RHS
1012 return DAG.getNode(ISD::ADD, VT, N1, N0);
1013 // fold (add x, 0) -> x
1014 if (N1C && N1C->isNullValue())
1016 // fold (add Sym, c) -> Sym+c
1017 if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(N0))
1018 if (!LegalOperations && TLI.isOffsetFoldingLegal(GA) && N1C &&
1019 GA->getOpcode() == ISD::GlobalAddress)
1020 return DAG.getGlobalAddress(GA->getGlobal(), VT,
1022 (uint64_t)N1C->getSExtValue());
1023 // fold ((c1-A)+c2) -> (c1+c2)-A
1024 if (N1C && N0.getOpcode() == ISD::SUB)
1025 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getOperand(0)))
1026 return DAG.getNode(ISD::SUB, VT,
1027 DAG.getConstant(N1C->getAPIntValue()+
1028 N0C->getAPIntValue(), VT),
1031 SDValue RADD = ReassociateOps(ISD::ADD, N->getDebugLoc(), N0, N1);
1032 if (RADD.getNode() != 0)
1034 // fold ((0-A) + B) -> B-A
1035 if (N0.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N0.getOperand(0)) &&
1036 cast<ConstantSDNode>(N0.getOperand(0))->isNullValue())
1037 return DAG.getNode(ISD::SUB, VT, N1, N0.getOperand(1));
1038 // fold (A + (0-B)) -> A-B
1039 if (N1.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N1.getOperand(0)) &&
1040 cast<ConstantSDNode>(N1.getOperand(0))->isNullValue())
1041 return DAG.getNode(ISD::SUB, VT, N0, N1.getOperand(1));
1042 // fold (A+(B-A)) -> B
1043 if (N1.getOpcode() == ISD::SUB && N0 == N1.getOperand(1))
1044 return N1.getOperand(0);
1045 // fold ((B-A)+A) -> B
1046 if (N0.getOpcode() == ISD::SUB && N1 == N0.getOperand(1))
1047 return N0.getOperand(0);
1048 // fold (A+(B-(A+C))) to (B-C)
1049 if (N1.getOpcode() == ISD::SUB && N1.getOperand(1).getOpcode() == ISD::ADD &&
1050 N0 == N1.getOperand(1).getOperand(0)) {
1051 return DAG.getNode(ISD::SUB, VT, N1.getOperand(0),
1052 N1.getOperand(1).getOperand(1));
1054 // fold (A+(B-(C+A))) to (B-C)
1055 if (N1.getOpcode() == ISD::SUB && N1.getOperand(1).getOpcode() == ISD::ADD &&
1056 N0 == N1.getOperand(1).getOperand(1)) {
1057 return DAG.getNode(ISD::SUB, VT, N1.getOperand(0),
1058 N1.getOperand(1).getOperand(0));
1060 // fold (A+((B-A)+or-C)) to (B+or-C)
1061 if ((N1.getOpcode() == ISD::SUB || N1.getOpcode() == ISD::ADD) &&
1062 N1.getOperand(0).getOpcode() == ISD::SUB &&
1063 N0 == N1.getOperand(0).getOperand(1)) {
1064 return DAG.getNode(N1.getOpcode(), VT, N1.getOperand(0).getOperand(0),
1068 // fold (A-B)+(C-D) to (A+C)-(B+D) when A or C is constant
1069 if (N0.getOpcode() == ISD::SUB && N1.getOpcode() == ISD::SUB) {
1070 SDValue N00 = N0.getOperand(0);
1071 SDValue N01 = N0.getOperand(1);
1072 SDValue N10 = N1.getOperand(0);
1073 SDValue N11 = N1.getOperand(1);
1074 if (isa<ConstantSDNode>(N00) || isa<ConstantSDNode>(N10)) {
1075 return DAG.getNode(ISD::SUB, VT,
1076 DAG.getNode(ISD::ADD, VT, N00, N10),
1077 DAG.getNode(ISD::ADD, VT, N01, N11));
1081 if (!VT.isVector() && SimplifyDemandedBits(SDValue(N, 0)))
1082 return SDValue(N, 0);
1084 // fold (a+b) -> (a|b) iff a and b share no bits.
1085 if (VT.isInteger() && !VT.isVector()) {
1086 APInt LHSZero, LHSOne;
1087 APInt RHSZero, RHSOne;
1088 APInt Mask = APInt::getAllOnesValue(VT.getSizeInBits());
1089 DAG.ComputeMaskedBits(N0, Mask, LHSZero, LHSOne);
1090 if (LHSZero.getBoolValue()) {
1091 DAG.ComputeMaskedBits(N1, Mask, RHSZero, RHSOne);
1093 // If all possibly-set bits on the LHS are clear on the RHS, return an OR.
1094 // If all possibly-set bits on the RHS are clear on the LHS, return an OR.
1095 if ((RHSZero & (~LHSZero & Mask)) == (~LHSZero & Mask) ||
1096 (LHSZero & (~RHSZero & Mask)) == (~RHSZero & Mask))
1097 return DAG.getNode(ISD::OR, VT, N0, N1);
1101 // fold (add (shl (add x, c1), c2), ) -> (add (add (shl x, c2), c1<<c2), )
1102 if (N0.getOpcode() == ISD::SHL && N0.getNode()->hasOneUse()) {
1103 SDValue Result = combineShlAddConstant(N0, N1, DAG);
1104 if (Result.getNode()) return Result;
1106 if (N1.getOpcode() == ISD::SHL && N1.getNode()->hasOneUse()) {
1107 SDValue Result = combineShlAddConstant(N1, N0, DAG);
1108 if (Result.getNode()) return Result;
1111 // fold (add (select cc, 0, c), x) -> (select cc, x, (add, x, c))
1112 if (N0.getOpcode() == ISD::SELECT && N0.getNode()->hasOneUse()) {
1113 SDValue Result = combineSelectAndUse(N, N0, N1, DAG, TLI, LegalOperations);
1114 if (Result.getNode()) return Result;
1116 if (N1.getOpcode() == ISD::SELECT && N1.getNode()->hasOneUse()) {
1117 SDValue Result = combineSelectAndUse(N, N1, N0, DAG, TLI, LegalOperations);
1118 if (Result.getNode()) return Result;
1124 SDValue DAGCombiner::visitADDC(SDNode *N) {
1125 SDValue N0 = N->getOperand(0);
1126 SDValue N1 = N->getOperand(1);
1127 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1128 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1129 MVT VT = N0.getValueType();
1131 // If the flag result is dead, turn this into an ADD.
1132 if (N->hasNUsesOfValue(0, 1))
1133 return CombineTo(N, DAG.getNode(ISD::ADD, VT, N1, N0),
1134 DAG.getNode(ISD::CARRY_FALSE, MVT::Flag));
1136 // canonicalize constant to RHS.
1138 return DAG.getNode(ISD::ADDC, N->getVTList(), N1, N0);
1140 // fold (addc x, 0) -> x + no carry out
1141 if (N1C && N1C->isNullValue())
1142 return CombineTo(N, N0, DAG.getNode(ISD::CARRY_FALSE, MVT::Flag));
1144 // fold (addc a, b) -> (or a, b), CARRY_FALSE iff a and b share no bits.
1145 APInt LHSZero, LHSOne;
1146 APInt RHSZero, RHSOne;
1147 APInt Mask = APInt::getAllOnesValue(VT.getSizeInBits());
1148 DAG.ComputeMaskedBits(N0, Mask, LHSZero, LHSOne);
1149 if (LHSZero.getBoolValue()) {
1150 DAG.ComputeMaskedBits(N1, Mask, RHSZero, RHSOne);
1152 // If all possibly-set bits on the LHS are clear on the RHS, return an OR.
1153 // If all possibly-set bits on the RHS are clear on the LHS, return an OR.
1154 if ((RHSZero & (~LHSZero & Mask)) == (~LHSZero & Mask) ||
1155 (LHSZero & (~RHSZero & Mask)) == (~RHSZero & Mask))
1156 return CombineTo(N, DAG.getNode(ISD::OR, VT, N0, N1),
1157 DAG.getNode(ISD::CARRY_FALSE, MVT::Flag));
1163 SDValue DAGCombiner::visitADDE(SDNode *N) {
1164 SDValue N0 = N->getOperand(0);
1165 SDValue N1 = N->getOperand(1);
1166 SDValue CarryIn = N->getOperand(2);
1167 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1168 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1169 //MVT VT = N0.getValueType();
1171 // canonicalize constant to RHS
1173 return DAG.getNode(ISD::ADDE, N->getVTList(), N1, N0, CarryIn);
1175 // fold (adde x, y, false) -> (addc x, y)
1176 if (CarryIn.getOpcode() == ISD::CARRY_FALSE)
1177 return DAG.getNode(ISD::ADDC, N->getVTList(), N1, N0);
1184 SDValue DAGCombiner::visitSUB(SDNode *N) {
1185 SDValue N0 = N->getOperand(0);
1186 SDValue N1 = N->getOperand(1);
1187 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getNode());
1188 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode());
1189 MVT VT = N0.getValueType();
1192 if (VT.isVector()) {
1193 SDValue FoldedVOp = SimplifyVBinOp(N);
1194 if (FoldedVOp.getNode()) return FoldedVOp;
1197 // fold (sub x, x) -> 0
1199 return DAG.getConstant(0, N->getValueType(0));
1200 // fold (sub c1, c2) -> c1-c2
1202 return DAG.FoldConstantArithmetic(ISD::SUB, VT, N0C, N1C);
1203 // fold (sub x, c) -> (add x, -c)
1205 return DAG.getNode(ISD::ADD, VT, N0,
1206 DAG.getConstant(-N1C->getAPIntValue(), VT));
1207 // fold (A+B)-A -> B
1208 if (N0.getOpcode() == ISD::ADD && N0.getOperand(0) == N1)
1209 return N0.getOperand(1);
1210 // fold (A+B)-B -> A
1211 if (N0.getOpcode() == ISD::ADD && N0.getOperand(1) == N1)
1212 return N0.getOperand(0);
1213 // fold ((A+(B+or-C))-B) -> A+or-C
1214 if (N0.getOpcode() == ISD::ADD &&
1215 (N0.getOperand(1).getOpcode() == ISD::SUB ||
1216 N0.getOperand(1).getOpcode() == ISD::ADD) &&
1217 N0.getOperand(1).getOperand(0) == N1)
1218 return DAG.getNode(N0.getOperand(1).getOpcode(), VT, N0.getOperand(0),
1219 N0.getOperand(1).getOperand(1));
1220 // fold ((A+(C+B))-B) -> A+C
1221 if (N0.getOpcode() == ISD::ADD &&
1222 N0.getOperand(1).getOpcode() == ISD::ADD &&
1223 N0.getOperand(1).getOperand(1) == N1)
1224 return DAG.getNode(ISD::ADD, VT, N0.getOperand(0),
1225 N0.getOperand(1).getOperand(0));
1226 // fold ((A-(B-C))-C) -> A-B
1227 if (N0.getOpcode() == ISD::SUB &&
1228 N0.getOperand(1).getOpcode() == ISD::SUB &&
1229 N0.getOperand(1).getOperand(1) == N1)
1230 return DAG.getNode(ISD::SUB, VT, N0.getOperand(0),
1231 N0.getOperand(1).getOperand(0));
1232 // fold (sub x, (select cc, 0, c)) -> (select cc, x, (sub, x, c))
1233 if (N1.getOpcode() == ISD::SELECT && N1.getNode()->hasOneUse()) {
1234 SDValue Result = combineSelectAndUse(N, N1, N0, DAG, TLI, LegalOperations);
1235 if (Result.getNode()) return Result;
1237 // If either operand of a sub is undef, the result is undef
1238 if (N0.getOpcode() == ISD::UNDEF)
1240 if (N1.getOpcode() == ISD::UNDEF)
1243 // If the relocation model supports it, consider symbol offsets.
1244 if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(N0))
1245 if (!LegalOperations && TLI.isOffsetFoldingLegal(GA)) {
1246 // fold (sub Sym, c) -> Sym-c
1247 if (N1C && GA->getOpcode() == ISD::GlobalAddress)
1248 return DAG.getGlobalAddress(GA->getGlobal(), VT,
1250 (uint64_t)N1C->getSExtValue());
1251 // fold (sub Sym+c1, Sym+c2) -> c1-c2
1252 if (GlobalAddressSDNode *GB = dyn_cast<GlobalAddressSDNode>(N1))
1253 if (GA->getGlobal() == GB->getGlobal())
1254 return DAG.getConstant((uint64_t)GA->getOffset() - GB->getOffset(),
1261 SDValue DAGCombiner::visitMUL(SDNode *N) {
1262 SDValue N0 = N->getOperand(0);
1263 SDValue N1 = N->getOperand(1);
1264 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1265 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1266 MVT VT = N0.getValueType();
1269 if (VT.isVector()) {
1270 SDValue FoldedVOp = SimplifyVBinOp(N);
1271 if (FoldedVOp.getNode()) return FoldedVOp;
1274 // fold (mul x, undef) -> 0
1275 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF)
1276 return DAG.getConstant(0, VT);
1277 // fold (mul c1, c2) -> c1*c2
1279 return DAG.FoldConstantArithmetic(ISD::MUL, VT, N0C, N1C);
1280 // canonicalize constant to RHS
1282 return DAG.getNode(ISD::MUL, VT, N1, N0);
1283 // fold (mul x, 0) -> 0
1284 if (N1C && N1C->isNullValue())
1286 // fold (mul x, -1) -> 0-x
1287 if (N1C && N1C->isAllOnesValue())
1288 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), N0);
1289 // fold (mul x, (1 << c)) -> x << c
1290 if (N1C && N1C->getAPIntValue().isPowerOf2())
1291 return DAG.getNode(ISD::SHL, VT, N0,
1292 DAG.getConstant(N1C->getAPIntValue().logBase2(),
1293 TLI.getShiftAmountTy()));
1294 // fold (mul x, -(1 << c)) -> -(x << c) or (-x) << c
1295 if (N1C && isPowerOf2_64(-N1C->getSExtValue())) {
1296 // FIXME: If the input is something that is easily negated (e.g. a
1297 // single-use add), we should put the negate there.
1298 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT),
1299 DAG.getNode(ISD::SHL, VT, N0,
1300 DAG.getConstant(Log2_64(-N1C->getSExtValue()),
1301 TLI.getShiftAmountTy())));
1304 // (mul (shl X, c1), c2) -> (mul X, c2 << c1)
1305 if (N1C && N0.getOpcode() == ISD::SHL &&
1306 isa<ConstantSDNode>(N0.getOperand(1))) {
1307 SDValue C3 = DAG.getNode(ISD::SHL, VT, N1, N0.getOperand(1));
1308 AddToWorkList(C3.getNode());
1309 return DAG.getNode(ISD::MUL, VT, N0.getOperand(0), C3);
1312 // Change (mul (shl X, C), Y) -> (shl (mul X, Y), C) when the shift has one
1315 SDValue Sh(0,0), Y(0,0);
1316 // Check for both (mul (shl X, C), Y) and (mul Y, (shl X, C)).
1317 if (N0.getOpcode() == ISD::SHL && isa<ConstantSDNode>(N0.getOperand(1)) &&
1318 N0.getNode()->hasOneUse()) {
1320 } else if (N1.getOpcode() == ISD::SHL &&
1321 isa<ConstantSDNode>(N1.getOperand(1)) &&
1322 N1.getNode()->hasOneUse()) {
1326 SDValue Mul = DAG.getNode(ISD::MUL, VT, Sh.getOperand(0), Y);
1327 return DAG.getNode(ISD::SHL, VT, Mul, Sh.getOperand(1));
1330 // fold (mul (add x, c1), c2) -> (add (mul x, c2), c1*c2)
1331 if (N1C && N0.getOpcode() == ISD::ADD && N0.getNode()->hasOneUse() &&
1332 isa<ConstantSDNode>(N0.getOperand(1))) {
1333 return DAG.getNode(ISD::ADD, VT,
1334 DAG.getNode(ISD::MUL, VT, N0.getOperand(0), N1),
1335 DAG.getNode(ISD::MUL, VT, N0.getOperand(1), N1));
1339 SDValue RMUL = ReassociateOps(ISD::MUL, N->getDebugLoc(), N0, N1);
1340 if (RMUL.getNode() != 0)
1346 SDValue DAGCombiner::visitSDIV(SDNode *N) {
1347 SDValue N0 = N->getOperand(0);
1348 SDValue N1 = N->getOperand(1);
1349 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getNode());
1350 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode());
1351 MVT VT = N->getValueType(0);
1354 if (VT.isVector()) {
1355 SDValue FoldedVOp = SimplifyVBinOp(N);
1356 if (FoldedVOp.getNode()) return FoldedVOp;
1359 // fold (sdiv c1, c2) -> c1/c2
1360 if (N0C && N1C && !N1C->isNullValue())
1361 return DAG.FoldConstantArithmetic(ISD::SDIV, VT, N0C, N1C);
1362 // fold (sdiv X, 1) -> X
1363 if (N1C && N1C->getSExtValue() == 1LL)
1365 // fold (sdiv X, -1) -> 0-X
1366 if (N1C && N1C->isAllOnesValue())
1367 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), N0);
1368 // If we know the sign bits of both operands are zero, strength reduce to a
1369 // udiv instead. Handles (X&15) /s 4 -> X&15 >> 2
1370 if (!VT.isVector()) {
1371 if (DAG.SignBitIsZero(N1) && DAG.SignBitIsZero(N0))
1372 return DAG.getNode(ISD::UDIV, N1.getValueType(), N0, N1);
1374 // fold (sdiv X, pow2) -> simple ops after legalize
1375 if (N1C && !N1C->isNullValue() && !TLI.isIntDivCheap() &&
1376 (isPowerOf2_64(N1C->getSExtValue()) ||
1377 isPowerOf2_64(-N1C->getSExtValue()))) {
1378 // If dividing by powers of two is cheap, then don't perform the following
1380 if (TLI.isPow2DivCheap())
1382 int64_t pow2 = N1C->getSExtValue();
1383 int64_t abs2 = pow2 > 0 ? pow2 : -pow2;
1384 unsigned lg2 = Log2_64(abs2);
1385 // Splat the sign bit into the register
1386 SDValue SGN = DAG.getNode(ISD::SRA, VT, N0,
1387 DAG.getConstant(VT.getSizeInBits()-1,
1388 TLI.getShiftAmountTy()));
1389 AddToWorkList(SGN.getNode());
1390 // Add (N0 < 0) ? abs2 - 1 : 0;
1391 SDValue SRL = DAG.getNode(ISD::SRL, VT, SGN,
1392 DAG.getConstant(VT.getSizeInBits()-lg2,
1393 TLI.getShiftAmountTy()));
1394 SDValue ADD = DAG.getNode(ISD::ADD, VT, N0, SRL);
1395 AddToWorkList(SRL.getNode());
1396 AddToWorkList(ADD.getNode()); // Divide by pow2
1397 SDValue SRA = DAG.getNode(ISD::SRA, VT, ADD,
1398 DAG.getConstant(lg2, TLI.getShiftAmountTy()));
1399 // If we're dividing by a positive value, we're done. Otherwise, we must
1400 // negate the result.
1403 AddToWorkList(SRA.getNode());
1404 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), SRA);
1406 // if integer divide is expensive and we satisfy the requirements, emit an
1407 // alternate sequence.
1408 if (N1C && (N1C->getSExtValue() < -1 || N1C->getSExtValue() > 1) &&
1409 !TLI.isIntDivCheap()) {
1410 SDValue Op = BuildSDIV(N);
1411 if (Op.getNode()) return Op;
1415 if (N0.getOpcode() == ISD::UNDEF)
1416 return DAG.getConstant(0, VT);
1417 // X / undef -> undef
1418 if (N1.getOpcode() == ISD::UNDEF)
1424 SDValue DAGCombiner::visitUDIV(SDNode *N) {
1425 SDValue N0 = N->getOperand(0);
1426 SDValue N1 = N->getOperand(1);
1427 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getNode());
1428 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode());
1429 MVT VT = N->getValueType(0);
1432 if (VT.isVector()) {
1433 SDValue FoldedVOp = SimplifyVBinOp(N);
1434 if (FoldedVOp.getNode()) return FoldedVOp;
1437 // fold (udiv c1, c2) -> c1/c2
1438 if (N0C && N1C && !N1C->isNullValue())
1439 return DAG.FoldConstantArithmetic(ISD::UDIV, VT, N0C, N1C);
1440 // fold (udiv x, (1 << c)) -> x >>u c
1441 if (N1C && N1C->getAPIntValue().isPowerOf2())
1442 return DAG.getNode(ISD::SRL, VT, N0,
1443 DAG.getConstant(N1C->getAPIntValue().logBase2(),
1444 TLI.getShiftAmountTy()));
1445 // fold (udiv x, (shl c, y)) -> x >>u (log2(c)+y) iff c is power of 2
1446 if (N1.getOpcode() == ISD::SHL) {
1447 if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) {
1448 if (SHC->getAPIntValue().isPowerOf2()) {
1449 MVT ADDVT = N1.getOperand(1).getValueType();
1450 SDValue Add = DAG.getNode(ISD::ADD, ADDVT, N1.getOperand(1),
1451 DAG.getConstant(SHC->getAPIntValue()
1454 AddToWorkList(Add.getNode());
1455 return DAG.getNode(ISD::SRL, VT, N0, Add);
1459 // fold (udiv x, c) -> alternate
1460 if (N1C && !N1C->isNullValue() && !TLI.isIntDivCheap()) {
1461 SDValue Op = BuildUDIV(N);
1462 if (Op.getNode()) return Op;
1466 if (N0.getOpcode() == ISD::UNDEF)
1467 return DAG.getConstant(0, VT);
1468 // X / undef -> undef
1469 if (N1.getOpcode() == ISD::UNDEF)
1475 SDValue DAGCombiner::visitSREM(SDNode *N) {
1476 SDValue N0 = N->getOperand(0);
1477 SDValue N1 = N->getOperand(1);
1478 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1479 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1480 MVT VT = N->getValueType(0);
1482 // fold (srem c1, c2) -> c1%c2
1483 if (N0C && N1C && !N1C->isNullValue())
1484 return DAG.FoldConstantArithmetic(ISD::SREM, VT, N0C, N1C);
1485 // If we know the sign bits of both operands are zero, strength reduce to a
1486 // urem instead. Handles (X & 0x0FFFFFFF) %s 16 -> X&15
1487 if (!VT.isVector()) {
1488 if (DAG.SignBitIsZero(N1) && DAG.SignBitIsZero(N0))
1489 return DAG.getNode(ISD::UREM, VT, N0, N1);
1492 // If X/C can be simplified by the division-by-constant logic, lower
1493 // X%C to the equivalent of X-X/C*C.
1494 if (N1C && !N1C->isNullValue()) {
1495 SDValue Div = DAG.getNode(ISD::SDIV, VT, N0, N1);
1496 AddToWorkList(Div.getNode());
1497 SDValue OptimizedDiv = combine(Div.getNode());
1498 if (OptimizedDiv.getNode() && OptimizedDiv.getNode() != Div.getNode()) {
1499 SDValue Mul = DAG.getNode(ISD::MUL, VT, OptimizedDiv, N1);
1500 SDValue Sub = DAG.getNode(ISD::SUB, VT, N0, Mul);
1501 AddToWorkList(Mul.getNode());
1507 if (N0.getOpcode() == ISD::UNDEF)
1508 return DAG.getConstant(0, VT);
1509 // X % undef -> undef
1510 if (N1.getOpcode() == ISD::UNDEF)
1516 SDValue DAGCombiner::visitUREM(SDNode *N) {
1517 SDValue N0 = N->getOperand(0);
1518 SDValue N1 = N->getOperand(1);
1519 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1520 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1521 MVT VT = N->getValueType(0);
1523 // fold (urem c1, c2) -> c1%c2
1524 if (N0C && N1C && !N1C->isNullValue())
1525 return DAG.FoldConstantArithmetic(ISD::UREM, VT, N0C, N1C);
1526 // fold (urem x, pow2) -> (and x, pow2-1)
1527 if (N1C && !N1C->isNullValue() && N1C->getAPIntValue().isPowerOf2())
1528 return DAG.getNode(ISD::AND, VT, N0,
1529 DAG.getConstant(N1C->getAPIntValue()-1,VT));
1530 // fold (urem x, (shl pow2, y)) -> (and x, (add (shl pow2, y), -1))
1531 if (N1.getOpcode() == ISD::SHL) {
1532 if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) {
1533 if (SHC->getAPIntValue().isPowerOf2()) {
1535 DAG.getNode(ISD::ADD, VT, N1,
1536 DAG.getConstant(APInt::getAllOnesValue(VT.getSizeInBits()),
1538 AddToWorkList(Add.getNode());
1539 return DAG.getNode(ISD::AND, VT, N0, Add);
1544 // If X/C can be simplified by the division-by-constant logic, lower
1545 // X%C to the equivalent of X-X/C*C.
1546 if (N1C && !N1C->isNullValue()) {
1547 SDValue Div = DAG.getNode(ISD::UDIV, VT, N0, N1);
1548 AddToWorkList(Div.getNode());
1549 SDValue OptimizedDiv = combine(Div.getNode());
1550 if (OptimizedDiv.getNode() && OptimizedDiv.getNode() != Div.getNode()) {
1551 SDValue Mul = DAG.getNode(ISD::MUL, VT, OptimizedDiv, N1);
1552 SDValue Sub = DAG.getNode(ISD::SUB, VT, N0, Mul);
1553 AddToWorkList(Mul.getNode());
1559 if (N0.getOpcode() == ISD::UNDEF)
1560 return DAG.getConstant(0, VT);
1561 // X % undef -> undef
1562 if (N1.getOpcode() == ISD::UNDEF)
1568 SDValue DAGCombiner::visitMULHS(SDNode *N) {
1569 SDValue N0 = N->getOperand(0);
1570 SDValue N1 = N->getOperand(1);
1571 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1572 MVT VT = N->getValueType(0);
1574 // fold (mulhs x, 0) -> 0
1575 if (N1C && N1C->isNullValue())
1577 // fold (mulhs x, 1) -> (sra x, size(x)-1)
1578 if (N1C && N1C->getAPIntValue() == 1)
1579 return DAG.getNode(ISD::SRA, N0.getValueType(), N0,
1580 DAG.getConstant(N0.getValueType().getSizeInBits()-1,
1581 TLI.getShiftAmountTy()));
1582 // fold (mulhs x, undef) -> 0
1583 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF)
1584 return DAG.getConstant(0, VT);
1589 SDValue DAGCombiner::visitMULHU(SDNode *N) {
1590 SDValue N0 = N->getOperand(0);
1591 SDValue N1 = N->getOperand(1);
1592 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1593 MVT VT = N->getValueType(0);
1595 // fold (mulhu x, 0) -> 0
1596 if (N1C && N1C->isNullValue())
1598 // fold (mulhu x, 1) -> 0
1599 if (N1C && N1C->getAPIntValue() == 1)
1600 return DAG.getConstant(0, N0.getValueType());
1601 // fold (mulhu x, undef) -> 0
1602 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF)
1603 return DAG.getConstant(0, VT);
1608 /// SimplifyNodeWithTwoResults - Perform optimizations common to nodes that
1609 /// compute two values. LoOp and HiOp give the opcodes for the two computations
1610 /// that are being performed. Return true if a simplification was made.
1612 SDValue DAGCombiner::SimplifyNodeWithTwoResults(SDNode *N, unsigned LoOp,
1614 // If the high half is not needed, just compute the low half.
1615 bool HiExists = N->hasAnyUseOfValue(1);
1617 (!LegalOperations ||
1618 TLI.isOperationLegal(LoOp, N->getValueType(0)))) {
1619 SDValue Res = DAG.getNode(LoOp, N->getValueType(0), N->op_begin(),
1620 N->getNumOperands());
1621 return CombineTo(N, Res, Res);
1624 // If the low half is not needed, just compute the high half.
1625 bool LoExists = N->hasAnyUseOfValue(0);
1627 (!LegalOperations ||
1628 TLI.isOperationLegal(HiOp, N->getValueType(1)))) {
1629 SDValue Res = DAG.getNode(HiOp, N->getValueType(1), N->op_begin(),
1630 N->getNumOperands());
1631 return CombineTo(N, Res, Res);
1634 // If both halves are used, return as it is.
1635 if (LoExists && HiExists)
1638 // If the two computed results can be simplified separately, separate them.
1640 SDValue Lo = DAG.getNode(LoOp, N->getValueType(0),
1641 N->op_begin(), N->getNumOperands());
1642 AddToWorkList(Lo.getNode());
1643 SDValue LoOpt = combine(Lo.getNode());
1644 if (LoOpt.getNode() && LoOpt.getNode() != Lo.getNode() &&
1645 (!LegalOperations ||
1646 TLI.isOperationLegal(LoOpt.getOpcode(), LoOpt.getValueType())))
1647 return CombineTo(N, LoOpt, LoOpt);
1651 SDValue Hi = DAG.getNode(HiOp, N->getValueType(1),
1652 N->op_begin(), N->getNumOperands());
1653 AddToWorkList(Hi.getNode());
1654 SDValue HiOpt = combine(Hi.getNode());
1655 if (HiOpt.getNode() && HiOpt != Hi &&
1656 (!LegalOperations ||
1657 TLI.isOperationLegal(HiOpt.getOpcode(), HiOpt.getValueType())))
1658 return CombineTo(N, HiOpt, HiOpt);
1663 SDValue DAGCombiner::visitSMUL_LOHI(SDNode *N) {
1664 SDValue Res = SimplifyNodeWithTwoResults(N, ISD::MUL, ISD::MULHS);
1665 if (Res.getNode()) return Res;
1670 SDValue DAGCombiner::visitUMUL_LOHI(SDNode *N) {
1671 SDValue Res = SimplifyNodeWithTwoResults(N, ISD::MUL, ISD::MULHU);
1672 if (Res.getNode()) return Res;
1677 SDValue DAGCombiner::visitSDIVREM(SDNode *N) {
1678 SDValue Res = SimplifyNodeWithTwoResults(N, ISD::SDIV, ISD::SREM);
1679 if (Res.getNode()) return Res;
1684 SDValue DAGCombiner::visitUDIVREM(SDNode *N) {
1685 SDValue Res = SimplifyNodeWithTwoResults(N, ISD::UDIV, ISD::UREM);
1686 if (Res.getNode()) return Res;
1691 /// SimplifyBinOpWithSameOpcodeHands - If this is a binary operator with
1692 /// two operands of the same opcode, try to simplify it.
1693 SDValue DAGCombiner::SimplifyBinOpWithSameOpcodeHands(SDNode *N) {
1694 SDValue N0 = N->getOperand(0), N1 = N->getOperand(1);
1695 MVT VT = N0.getValueType();
1696 assert(N0.getOpcode() == N1.getOpcode() && "Bad input!");
1698 // For each of OP in AND/OR/XOR:
1699 // fold (OP (zext x), (zext y)) -> (zext (OP x, y))
1700 // fold (OP (sext x), (sext y)) -> (sext (OP x, y))
1701 // fold (OP (aext x), (aext y)) -> (aext (OP x, y))
1702 // fold (OP (trunc x), (trunc y)) -> (trunc (OP x, y))
1703 if ((N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND||
1704 N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::TRUNCATE) &&
1705 N0.getOperand(0).getValueType() == N1.getOperand(0).getValueType()) {
1706 SDValue ORNode = DAG.getNode(N->getOpcode(),
1707 N0.getOperand(0).getValueType(),
1708 N0.getOperand(0), N1.getOperand(0));
1709 AddToWorkList(ORNode.getNode());
1710 return DAG.getNode(N0.getOpcode(), VT, ORNode);
1713 // For each of OP in SHL/SRL/SRA/AND...
1714 // fold (and (OP x, z), (OP y, z)) -> (OP (and x, y), z)
1715 // fold (or (OP x, z), (OP y, z)) -> (OP (or x, y), z)
1716 // fold (xor (OP x, z), (OP y, z)) -> (OP (xor x, y), z)
1717 if ((N0.getOpcode() == ISD::SHL || N0.getOpcode() == ISD::SRL ||
1718 N0.getOpcode() == ISD::SRA || N0.getOpcode() == ISD::AND) &&
1719 N0.getOperand(1) == N1.getOperand(1)) {
1720 SDValue ORNode = DAG.getNode(N->getOpcode(),
1721 N0.getOperand(0).getValueType(),
1722 N0.getOperand(0), N1.getOperand(0));
1723 AddToWorkList(ORNode.getNode());
1724 return DAG.getNode(N0.getOpcode(), VT, ORNode, N0.getOperand(1));
1730 SDValue DAGCombiner::visitAND(SDNode *N) {
1731 SDValue N0 = N->getOperand(0);
1732 SDValue N1 = N->getOperand(1);
1733 SDValue LL, LR, RL, RR, CC0, CC1;
1734 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1735 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1736 MVT VT = N1.getValueType();
1737 unsigned BitWidth = VT.getSizeInBits();
1740 if (VT.isVector()) {
1741 SDValue FoldedVOp = SimplifyVBinOp(N);
1742 if (FoldedVOp.getNode()) return FoldedVOp;
1745 // fold (and x, undef) -> 0
1746 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF)
1747 return DAG.getConstant(0, VT);
1748 // fold (and c1, c2) -> c1&c2
1750 return DAG.FoldConstantArithmetic(ISD::AND, VT, N0C, N1C);
1751 // canonicalize constant to RHS
1753 return DAG.getNode(ISD::AND, VT, N1, N0);
1754 // fold (and x, -1) -> x
1755 if (N1C && N1C->isAllOnesValue())
1757 // if (and x, c) is known to be zero, return 0
1758 if (N1C && DAG.MaskedValueIsZero(SDValue(N, 0),
1759 APInt::getAllOnesValue(BitWidth)))
1760 return DAG.getConstant(0, VT);
1762 SDValue RAND = ReassociateOps(ISD::AND, N->getDebugLoc(), N0, N1);
1763 if (RAND.getNode() != 0)
1765 // fold (and (or x, 0xFFFF), 0xFF) -> 0xFF
1766 if (N1C && N0.getOpcode() == ISD::OR)
1767 if (ConstantSDNode *ORI = dyn_cast<ConstantSDNode>(N0.getOperand(1)))
1768 if ((ORI->getAPIntValue() & N1C->getAPIntValue()) == N1C->getAPIntValue())
1770 // fold (and (any_ext V), c) -> (zero_ext V) if 'and' only clears top bits.
1771 if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) {
1772 SDValue N0Op0 = N0.getOperand(0);
1773 APInt Mask = ~N1C->getAPIntValue();
1774 Mask.trunc(N0Op0.getValueSizeInBits());
1775 if (DAG.MaskedValueIsZero(N0Op0, Mask)) {
1776 SDValue Zext = DAG.getNode(ISD::ZERO_EXTEND, N0.getValueType(),
1779 // Replace uses of the AND with uses of the Zero extend node.
1782 // We actually want to replace all uses of the any_extend with the
1783 // zero_extend, to avoid duplicating things. This will later cause this
1784 // AND to be folded.
1785 CombineTo(N0.getNode(), Zext);
1786 return SDValue(N, 0); // Return N so it doesn't get rechecked!
1789 // fold (and (setcc x), (setcc y)) -> (setcc (and x, y))
1790 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){
1791 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get();
1792 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get();
1794 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 &&
1795 LL.getValueType().isInteger()) {
1796 // fold (X == 0) & (Y == 0) -> (X|Y == 0)
1797 if (cast<ConstantSDNode>(LR)->isNullValue() && Op1 == ISD::SETEQ) {
1798 SDValue ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL);
1799 AddToWorkList(ORNode.getNode());
1800 return DAG.getSetCC(VT, ORNode, LR, Op1);
1802 // fold (X == -1) & (Y == -1) -> (X&Y == -1)
1803 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETEQ) {
1804 SDValue ANDNode = DAG.getNode(ISD::AND, LR.getValueType(), LL, RL);
1805 AddToWorkList(ANDNode.getNode());
1806 return DAG.getSetCC(VT, ANDNode, LR, Op1);
1808 // fold (X > -1) & (Y > -1) -> (X|Y > -1)
1809 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETGT) {
1810 SDValue ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL);
1811 AddToWorkList(ORNode.getNode());
1812 return DAG.getSetCC(VT, ORNode, LR, Op1);
1815 // canonicalize equivalent to ll == rl
1816 if (LL == RR && LR == RL) {
1817 Op1 = ISD::getSetCCSwappedOperands(Op1);
1820 if (LL == RL && LR == RR) {
1821 bool isInteger = LL.getValueType().isInteger();
1822 ISD::CondCode Result = ISD::getSetCCAndOperation(Op0, Op1, isInteger);
1823 if (Result != ISD::SETCC_INVALID &&
1824 (!LegalOperations || TLI.isCondCodeLegal(Result, LL.getValueType())))
1825 return DAG.getSetCC(N0.getValueType(), LL, LR, Result);
1829 // Simplify: and (op x...), (op y...) -> (op (and x, y))
1830 if (N0.getOpcode() == N1.getOpcode()) {
1831 SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N);
1832 if (Tmp.getNode()) return Tmp;
1835 // fold (and (sign_extend_inreg x, i16 to i32), 1) -> (and x, 1)
1836 // fold (and (sra)) -> (and (srl)) when possible.
1837 if (!VT.isVector() &&
1838 SimplifyDemandedBits(SDValue(N, 0)))
1839 return SDValue(N, 0);
1840 // fold (zext_inreg (extload x)) -> (zextload x)
1841 if (ISD::isEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode())) {
1842 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
1843 MVT EVT = LN0->getMemoryVT();
1844 // If we zero all the possible extended bits, then we can turn this into
1845 // a zextload if we are running before legalize or the operation is legal.
1846 unsigned BitWidth = N1.getValueSizeInBits();
1847 if (DAG.MaskedValueIsZero(N1, APInt::getHighBitsSet(BitWidth,
1848 BitWidth - EVT.getSizeInBits())) &&
1849 ((!LegalOperations && !LN0->isVolatile()) ||
1850 TLI.isLoadExtLegal(ISD::ZEXTLOAD, EVT))) {
1851 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, LN0->getChain(),
1852 LN0->getBasePtr(), LN0->getSrcValue(),
1853 LN0->getSrcValueOffset(), EVT,
1854 LN0->isVolatile(), LN0->getAlignment());
1856 CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1));
1857 return SDValue(N, 0); // Return N so it doesn't get rechecked!
1860 // fold (zext_inreg (sextload x)) -> (zextload x) iff load has one use
1861 if (ISD::isSEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) &&
1863 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
1864 MVT EVT = LN0->getMemoryVT();
1865 // If we zero all the possible extended bits, then we can turn this into
1866 // a zextload if we are running before legalize or the operation is legal.
1867 unsigned BitWidth = N1.getValueSizeInBits();
1868 if (DAG.MaskedValueIsZero(N1, APInt::getHighBitsSet(BitWidth,
1869 BitWidth - EVT.getSizeInBits())) &&
1870 ((!LegalOperations && !LN0->isVolatile()) ||
1871 TLI.isLoadExtLegal(ISD::ZEXTLOAD, EVT))) {
1872 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, LN0->getChain(),
1873 LN0->getBasePtr(), LN0->getSrcValue(),
1874 LN0->getSrcValueOffset(), EVT,
1875 LN0->isVolatile(), LN0->getAlignment());
1877 CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1));
1878 return SDValue(N, 0); // Return N so it doesn't get rechecked!
1882 // fold (and (load x), 255) -> (zextload x, i8)
1883 // fold (and (extload x, i16), 255) -> (zextload x, i8)
1884 if (N1C && N0.getOpcode() == ISD::LOAD) {
1885 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
1886 if (LN0->getExtensionType() != ISD::SEXTLOAD &&
1887 LN0->isUnindexed() && N0.hasOneUse() &&
1888 // Do not change the width of a volatile load.
1889 !LN0->isVolatile()) {
1890 MVT EVT = MVT::Other;
1891 uint32_t ActiveBits = N1C->getAPIntValue().getActiveBits();
1892 if (ActiveBits > 0 && APIntOps::isMask(ActiveBits, N1C->getAPIntValue()))
1893 EVT = MVT::getIntegerVT(ActiveBits);
1895 MVT LoadedVT = LN0->getMemoryVT();
1896 // Do not generate loads of non-round integer types since these can
1897 // be expensive (and would be wrong if the type is not byte sized).
1898 if (EVT != MVT::Other && LoadedVT.bitsGT(EVT) && EVT.isRound() &&
1899 (!LegalOperations || TLI.isLoadExtLegal(ISD::ZEXTLOAD, EVT))) {
1900 MVT PtrType = N0.getOperand(1).getValueType();
1901 // For big endian targets, we need to add an offset to the pointer to
1902 // load the correct bytes. For little endian systems, we merely need to
1903 // read fewer bytes from the same pointer.
1904 unsigned LVTStoreBytes = LoadedVT.getStoreSizeInBits()/8;
1905 unsigned EVTStoreBytes = EVT.getStoreSizeInBits()/8;
1906 unsigned PtrOff = LVTStoreBytes - EVTStoreBytes;
1907 unsigned Alignment = LN0->getAlignment();
1908 SDValue NewPtr = LN0->getBasePtr();
1909 if (TLI.isBigEndian()) {
1910 NewPtr = DAG.getNode(ISD::ADD, PtrType, NewPtr,
1911 DAG.getConstant(PtrOff, PtrType));
1912 Alignment = MinAlign(Alignment, PtrOff);
1914 AddToWorkList(NewPtr.getNode());
1916 DAG.getExtLoad(ISD::ZEXTLOAD, VT, LN0->getChain(), NewPtr,
1917 LN0->getSrcValue(), LN0->getSrcValueOffset(), EVT,
1918 LN0->isVolatile(), Alignment);
1920 CombineTo(N0.getNode(), Load, Load.getValue(1));
1921 return SDValue(N, 0); // Return N so it doesn't get rechecked!
1929 SDValue DAGCombiner::visitOR(SDNode *N) {
1930 SDValue N0 = N->getOperand(0);
1931 SDValue N1 = N->getOperand(1);
1932 SDValue LL, LR, RL, RR, CC0, CC1;
1933 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1934 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1935 MVT VT = N1.getValueType();
1938 if (VT.isVector()) {
1939 SDValue FoldedVOp = SimplifyVBinOp(N);
1940 if (FoldedVOp.getNode()) return FoldedVOp;
1943 // fold (or x, undef) -> -1
1944 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF)
1945 return DAG.getConstant(~0ULL, VT);
1946 // fold (or c1, c2) -> c1|c2
1948 return DAG.FoldConstantArithmetic(ISD::OR, VT, N0C, N1C);
1949 // canonicalize constant to RHS
1951 return DAG.getNode(ISD::OR, VT, N1, N0);
1952 // fold (or x, 0) -> x
1953 if (N1C && N1C->isNullValue())
1955 // fold (or x, -1) -> -1
1956 if (N1C && N1C->isAllOnesValue())
1958 // fold (or x, c) -> c iff (x & ~c) == 0
1959 if (N1C && DAG.MaskedValueIsZero(N0, ~N1C->getAPIntValue()))
1962 SDValue ROR = ReassociateOps(ISD::OR, N->getDebugLoc(), N0, N1);
1963 if (ROR.getNode() != 0)
1965 // Canonicalize (or (and X, c1), c2) -> (and (or X, c2), c1|c2)
1966 if (N1C && N0.getOpcode() == ISD::AND && N0.getNode()->hasOneUse() &&
1967 isa<ConstantSDNode>(N0.getOperand(1))) {
1968 ConstantSDNode *C1 = cast<ConstantSDNode>(N0.getOperand(1));
1969 return DAG.getNode(ISD::AND, VT, DAG.getNode(ISD::OR, VT, N0.getOperand(0),
1971 DAG.getConstant(N1C->getAPIntValue() |
1972 C1->getAPIntValue(), VT));
1974 // fold (or (setcc x), (setcc y)) -> (setcc (or x, y))
1975 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){
1976 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get();
1977 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get();
1979 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 &&
1980 LL.getValueType().isInteger()) {
1981 // fold (X != 0) | (Y != 0) -> (X|Y != 0)
1982 // fold (X < 0) | (Y < 0) -> (X|Y < 0)
1983 if (cast<ConstantSDNode>(LR)->isNullValue() &&
1984 (Op1 == ISD::SETNE || Op1 == ISD::SETLT)) {
1985 SDValue ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL);
1986 AddToWorkList(ORNode.getNode());
1987 return DAG.getSetCC(VT, ORNode, LR, Op1);
1989 // fold (X != -1) | (Y != -1) -> (X&Y != -1)
1990 // fold (X > -1) | (Y > -1) -> (X&Y > -1)
1991 if (cast<ConstantSDNode>(LR)->isAllOnesValue() &&
1992 (Op1 == ISD::SETNE || Op1 == ISD::SETGT)) {
1993 SDValue ANDNode = DAG.getNode(ISD::AND, LR.getValueType(), LL, RL);
1994 AddToWorkList(ANDNode.getNode());
1995 return DAG.getSetCC(VT, ANDNode, LR, Op1);
1998 // canonicalize equivalent to ll == rl
1999 if (LL == RR && LR == RL) {
2000 Op1 = ISD::getSetCCSwappedOperands(Op1);
2003 if (LL == RL && LR == RR) {
2004 bool isInteger = LL.getValueType().isInteger();
2005 ISD::CondCode Result = ISD::getSetCCOrOperation(Op0, Op1, isInteger);
2006 if (Result != ISD::SETCC_INVALID &&
2007 (!LegalOperations || TLI.isCondCodeLegal(Result, LL.getValueType())))
2008 return DAG.getSetCC(N0.getValueType(), LL, LR, Result);
2012 // Simplify: or (op x...), (op y...) -> (op (or x, y))
2013 if (N0.getOpcode() == N1.getOpcode()) {
2014 SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N);
2015 if (Tmp.getNode()) return Tmp;
2018 // (X & C1) | (Y & C2) -> (X|Y) & C3 if possible.
2019 if (N0.getOpcode() == ISD::AND &&
2020 N1.getOpcode() == ISD::AND &&
2021 N0.getOperand(1).getOpcode() == ISD::Constant &&
2022 N1.getOperand(1).getOpcode() == ISD::Constant &&
2023 // Don't increase # computations.
2024 (N0.getNode()->hasOneUse() || N1.getNode()->hasOneUse())) {
2025 // We can only do this xform if we know that bits from X that are set in C2
2026 // but not in C1 are already zero. Likewise for Y.
2027 const APInt &LHSMask =
2028 cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue();
2029 const APInt &RHSMask =
2030 cast<ConstantSDNode>(N1.getOperand(1))->getAPIntValue();
2032 if (DAG.MaskedValueIsZero(N0.getOperand(0), RHSMask&~LHSMask) &&
2033 DAG.MaskedValueIsZero(N1.getOperand(0), LHSMask&~RHSMask)) {
2034 SDValue X =DAG.getNode(ISD::OR, VT, N0.getOperand(0), N1.getOperand(0));
2035 return DAG.getNode(ISD::AND, VT, X, DAG.getConstant(LHSMask|RHSMask, VT));
2040 // See if this is some rotate idiom.
2041 if (SDNode *Rot = MatchRotate(N0, N1))
2042 return SDValue(Rot, 0);
2048 /// MatchRotateHalf - Match "(X shl/srl V1) & V2" where V2 may not be present.
2049 static bool MatchRotateHalf(SDValue Op, SDValue &Shift, SDValue &Mask) {
2050 if (Op.getOpcode() == ISD::AND) {
2051 if (isa<ConstantSDNode>(Op.getOperand(1))) {
2052 Mask = Op.getOperand(1);
2053 Op = Op.getOperand(0);
2059 if (Op.getOpcode() == ISD::SRL || Op.getOpcode() == ISD::SHL) {
2067 // MatchRotate - Handle an 'or' of two operands. If this is one of the many
2068 // idioms for rotate, and if the target supports rotation instructions, generate
2070 SDNode *DAGCombiner::MatchRotate(SDValue LHS, SDValue RHS) {
2071 // Must be a legal type. Expanded 'n promoted things won't work with rotates.
2072 MVT VT = LHS.getValueType();
2073 if (!TLI.isTypeLegal(VT)) return 0;
2075 // The target must have at least one rotate flavor.
2076 bool HasROTL = TLI.isOperationLegalOrCustom(ISD::ROTL, VT);
2077 bool HasROTR = TLI.isOperationLegalOrCustom(ISD::ROTR, VT);
2078 if (!HasROTL && !HasROTR) return 0;
2080 // Match "(X shl/srl V1) & V2" where V2 may not be present.
2081 SDValue LHSShift; // The shift.
2082 SDValue LHSMask; // AND value if any.
2083 if (!MatchRotateHalf(LHS, LHSShift, LHSMask))
2084 return 0; // Not part of a rotate.
2086 SDValue RHSShift; // The shift.
2087 SDValue RHSMask; // AND value if any.
2088 if (!MatchRotateHalf(RHS, RHSShift, RHSMask))
2089 return 0; // Not part of a rotate.
2091 if (LHSShift.getOperand(0) != RHSShift.getOperand(0))
2092 return 0; // Not shifting the same value.
2094 if (LHSShift.getOpcode() == RHSShift.getOpcode())
2095 return 0; // Shifts must disagree.
2097 // Canonicalize shl to left side in a shl/srl pair.
2098 if (RHSShift.getOpcode() == ISD::SHL) {
2099 std::swap(LHS, RHS);
2100 std::swap(LHSShift, RHSShift);
2101 std::swap(LHSMask , RHSMask );
2104 unsigned OpSizeInBits = VT.getSizeInBits();
2105 SDValue LHSShiftArg = LHSShift.getOperand(0);
2106 SDValue LHSShiftAmt = LHSShift.getOperand(1);
2107 SDValue RHSShiftAmt = RHSShift.getOperand(1);
2109 // fold (or (shl x, C1), (srl x, C2)) -> (rotl x, C1)
2110 // fold (or (shl x, C1), (srl x, C2)) -> (rotr x, C2)
2111 if (LHSShiftAmt.getOpcode() == ISD::Constant &&
2112 RHSShiftAmt.getOpcode() == ISD::Constant) {
2113 uint64_t LShVal = cast<ConstantSDNode>(LHSShiftAmt)->getZExtValue();
2114 uint64_t RShVal = cast<ConstantSDNode>(RHSShiftAmt)->getZExtValue();
2115 if ((LShVal + RShVal) != OpSizeInBits)
2120 Rot = DAG.getNode(ISD::ROTL, VT, LHSShiftArg, LHSShiftAmt);
2122 Rot = DAG.getNode(ISD::ROTR, VT, LHSShiftArg, RHSShiftAmt);
2124 // If there is an AND of either shifted operand, apply it to the result.
2125 if (LHSMask.getNode() || RHSMask.getNode()) {
2126 APInt Mask = APInt::getAllOnesValue(OpSizeInBits);
2128 if (LHSMask.getNode()) {
2129 APInt RHSBits = APInt::getLowBitsSet(OpSizeInBits, LShVal);
2130 Mask &= cast<ConstantSDNode>(LHSMask)->getAPIntValue() | RHSBits;
2132 if (RHSMask.getNode()) {
2133 APInt LHSBits = APInt::getHighBitsSet(OpSizeInBits, RShVal);
2134 Mask &= cast<ConstantSDNode>(RHSMask)->getAPIntValue() | LHSBits;
2137 Rot = DAG.getNode(ISD::AND, VT, Rot, DAG.getConstant(Mask, VT));
2140 return Rot.getNode();
2143 // If there is a mask here, and we have a variable shift, we can't be sure
2144 // that we're masking out the right stuff.
2145 if (LHSMask.getNode() || RHSMask.getNode())
2148 // fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotl x, y)
2149 // fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotr x, (sub 32, y))
2150 if (RHSShiftAmt.getOpcode() == ISD::SUB &&
2151 LHSShiftAmt == RHSShiftAmt.getOperand(1)) {
2152 if (ConstantSDNode *SUBC =
2153 dyn_cast<ConstantSDNode>(RHSShiftAmt.getOperand(0))) {
2154 if (SUBC->getAPIntValue() == OpSizeInBits) {
2156 return DAG.getNode(ISD::ROTL, VT, LHSShiftArg, LHSShiftAmt).getNode();
2158 return DAG.getNode(ISD::ROTR, VT, LHSShiftArg, RHSShiftAmt).getNode();
2163 // fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotr x, y)
2164 // fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotl x, (sub 32, y))
2165 if (LHSShiftAmt.getOpcode() == ISD::SUB &&
2166 RHSShiftAmt == LHSShiftAmt.getOperand(1)) {
2167 if (ConstantSDNode *SUBC =
2168 dyn_cast<ConstantSDNode>(LHSShiftAmt.getOperand(0))) {
2169 if (SUBC->getAPIntValue() == OpSizeInBits) {
2171 return DAG.getNode(ISD::ROTR, VT, LHSShiftArg, RHSShiftAmt).getNode();
2173 return DAG.getNode(ISD::ROTL, VT, LHSShiftArg, LHSShiftAmt).getNode();
2178 // Look for sign/zext/any-extended or truncate cases:
2179 if ((LHSShiftAmt.getOpcode() == ISD::SIGN_EXTEND
2180 || LHSShiftAmt.getOpcode() == ISD::ZERO_EXTEND
2181 || LHSShiftAmt.getOpcode() == ISD::ANY_EXTEND
2182 || LHSShiftAmt.getOpcode() == ISD::TRUNCATE) &&
2183 (RHSShiftAmt.getOpcode() == ISD::SIGN_EXTEND
2184 || RHSShiftAmt.getOpcode() == ISD::ZERO_EXTEND
2185 || RHSShiftAmt.getOpcode() == ISD::ANY_EXTEND
2186 || RHSShiftAmt.getOpcode() == ISD::TRUNCATE)) {
2187 SDValue LExtOp0 = LHSShiftAmt.getOperand(0);
2188 SDValue RExtOp0 = RHSShiftAmt.getOperand(0);
2189 if (RExtOp0.getOpcode() == ISD::SUB &&
2190 RExtOp0.getOperand(1) == LExtOp0) {
2191 // fold (or (shl x, (*ext y)), (srl x, (*ext (sub 32, y)))) ->
2193 // fold (or (shl x, (*ext y)), (srl x, (*ext (sub 32, y)))) ->
2194 // (rotr x, (sub 32, y))
2195 if (ConstantSDNode *SUBC =
2196 dyn_cast<ConstantSDNode>(RExtOp0.getOperand(0))) {
2197 if (SUBC->getAPIntValue() == OpSizeInBits) {
2198 return DAG.getNode(HasROTL ? ISD::ROTL : ISD::ROTR, VT, LHSShiftArg,
2199 HasROTL ? LHSShiftAmt : RHSShiftAmt).getNode();
2202 } else if (LExtOp0.getOpcode() == ISD::SUB &&
2203 RExtOp0 == LExtOp0.getOperand(1)) {
2204 // fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext y))) ->
2206 // fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext y))) ->
2207 // (rotl x, (sub 32, y))
2208 if (ConstantSDNode *SUBC =
2209 dyn_cast<ConstantSDNode>(LExtOp0.getOperand(0))) {
2210 if (SUBC->getAPIntValue() == OpSizeInBits) {
2211 return DAG.getNode(HasROTR ? ISD::ROTR : ISD::ROTL, VT, LHSShiftArg,
2212 HasROTR ? RHSShiftAmt : LHSShiftAmt).getNode();
2222 SDValue DAGCombiner::visitXOR(SDNode *N) {
2223 SDValue N0 = N->getOperand(0);
2224 SDValue N1 = N->getOperand(1);
2225 SDValue LHS, RHS, CC;
2226 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
2227 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
2228 MVT VT = N0.getValueType();
2231 if (VT.isVector()) {
2232 SDValue FoldedVOp = SimplifyVBinOp(N);
2233 if (FoldedVOp.getNode()) return FoldedVOp;
2236 // fold (xor undef, undef) -> 0. This is a common idiom (misuse).
2237 if (N0.getOpcode() == ISD::UNDEF && N1.getOpcode() == ISD::UNDEF)
2238 return DAG.getConstant(0, VT);
2239 // fold (xor x, undef) -> undef
2240 if (N0.getOpcode() == ISD::UNDEF)
2242 if (N1.getOpcode() == ISD::UNDEF)
2244 // fold (xor c1, c2) -> c1^c2
2246 return DAG.FoldConstantArithmetic(ISD::XOR, VT, N0C, N1C);
2247 // canonicalize constant to RHS
2249 return DAG.getNode(ISD::XOR, VT, N1, N0);
2250 // fold (xor x, 0) -> x
2251 if (N1C && N1C->isNullValue())
2254 SDValue RXOR = ReassociateOps(ISD::XOR, N->getDebugLoc(), N0, N1);
2255 if (RXOR.getNode() != 0)
2258 // fold !(x cc y) -> (x !cc y)
2259 if (N1C && N1C->getAPIntValue() == 1 && isSetCCEquivalent(N0, LHS, RHS, CC)) {
2260 bool isInt = LHS.getValueType().isInteger();
2261 ISD::CondCode NotCC = ISD::getSetCCInverse(cast<CondCodeSDNode>(CC)->get(),
2264 if (!LegalOperations || TLI.isCondCodeLegal(NotCC, LHS.getValueType())) {
2265 switch (N0.getOpcode()) {
2267 assert(0 && "Unhandled SetCC Equivalent!");
2270 return DAG.getSetCC(VT, LHS, RHS, NotCC);
2271 case ISD::SELECT_CC:
2272 return DAG.getSelectCC(LHS, RHS, N0.getOperand(2),
2273 N0.getOperand(3), NotCC);
2278 // fold (not (zext (setcc x, y))) -> (zext (not (setcc x, y)))
2279 if (N1C && N1C->getAPIntValue() == 1 && N0.getOpcode() == ISD::ZERO_EXTEND &&
2280 N0.getNode()->hasOneUse() &&
2281 isSetCCEquivalent(N0.getOperand(0), LHS, RHS, CC)){
2282 SDValue V = N0.getOperand(0);
2283 V = DAG.getNode(ISD::XOR, V.getValueType(), V,
2284 DAG.getConstant(1, V.getValueType()));
2285 AddToWorkList(V.getNode());
2286 return DAG.getNode(ISD::ZERO_EXTEND, VT, V);
2289 // fold !(x or y) -> (!x and !y) iff x or y are setcc
2290 if (N1C && N1C->getAPIntValue() == 1 && VT == MVT::i1 &&
2291 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) {
2292 SDValue LHS = N0.getOperand(0), RHS = N0.getOperand(1);
2293 if (isOneUseSetCC(RHS) || isOneUseSetCC(LHS)) {
2294 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND;
2295 LHS = DAG.getNode(ISD::XOR, VT, LHS, N1); // RHS = ~LHS
2296 RHS = DAG.getNode(ISD::XOR, VT, RHS, N1); // RHS = ~RHS
2297 AddToWorkList(LHS.getNode()); AddToWorkList(RHS.getNode());
2298 return DAG.getNode(NewOpcode, VT, LHS, RHS);
2301 // fold !(x or y) -> (!x and !y) iff x or y are constants
2302 if (N1C && N1C->isAllOnesValue() &&
2303 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) {
2304 SDValue LHS = N0.getOperand(0), RHS = N0.getOperand(1);
2305 if (isa<ConstantSDNode>(RHS) || isa<ConstantSDNode>(LHS)) {
2306 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND;
2307 LHS = DAG.getNode(ISD::XOR, VT, LHS, N1); // RHS = ~LHS
2308 RHS = DAG.getNode(ISD::XOR, VT, RHS, N1); // RHS = ~RHS
2309 AddToWorkList(LHS.getNode()); AddToWorkList(RHS.getNode());
2310 return DAG.getNode(NewOpcode, VT, LHS, RHS);
2313 // fold (xor (xor x, c1), c2) -> (xor x, c1^c2)
2314 if (N1C && N0.getOpcode() == ISD::XOR) {
2315 ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0));
2316 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
2318 return DAG.getNode(ISD::XOR, VT, N0.getOperand(1),
2319 DAG.getConstant(N1C->getAPIntValue()^
2320 N00C->getAPIntValue(), VT));
2322 return DAG.getNode(ISD::XOR, VT, N0.getOperand(0),
2323 DAG.getConstant(N1C->getAPIntValue()^
2324 N01C->getAPIntValue(), VT));
2326 // fold (xor x, x) -> 0
2328 if (!VT.isVector()) {
2329 return DAG.getConstant(0, VT);
2330 } else if (!LegalOperations || TLI.isOperationLegal(ISD::BUILD_VECTOR, VT)){
2331 // Produce a vector of zeros.
2332 SDValue El = DAG.getConstant(0, VT.getVectorElementType());
2333 std::vector<SDValue> Ops(VT.getVectorNumElements(), El);
2334 return DAG.getNode(ISD::BUILD_VECTOR, VT, &Ops[0], Ops.size());
2338 // Simplify: xor (op x...), (op y...) -> (op (xor x, y))
2339 if (N0.getOpcode() == N1.getOpcode()) {
2340 SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N);
2341 if (Tmp.getNode()) return Tmp;
2344 // Simplify the expression using non-local knowledge.
2345 if (!VT.isVector() &&
2346 SimplifyDemandedBits(SDValue(N, 0)))
2347 return SDValue(N, 0);
2352 /// visitShiftByConstant - Handle transforms common to the three shifts, when
2353 /// the shift amount is a constant.
2354 SDValue DAGCombiner::visitShiftByConstant(SDNode *N, unsigned Amt) {
2355 SDNode *LHS = N->getOperand(0).getNode();
2356 if (!LHS->hasOneUse()) return SDValue();
2358 // We want to pull some binops through shifts, so that we have (and (shift))
2359 // instead of (shift (and)), likewise for add, or, xor, etc. This sort of
2360 // thing happens with address calculations, so it's important to canonicalize
2362 bool HighBitSet = false; // Can we transform this if the high bit is set?
2364 switch (LHS->getOpcode()) {
2365 default: return SDValue();
2368 HighBitSet = false; // We can only transform sra if the high bit is clear.
2371 HighBitSet = true; // We can only transform sra if the high bit is set.
2374 if (N->getOpcode() != ISD::SHL)
2375 return SDValue(); // only shl(add) not sr[al](add).
2376 HighBitSet = false; // We can only transform sra if the high bit is clear.
2380 // We require the RHS of the binop to be a constant as well.
2381 ConstantSDNode *BinOpCst = dyn_cast<ConstantSDNode>(LHS->getOperand(1));
2382 if (!BinOpCst) return SDValue();
2385 // FIXME: disable this for unless the input to the binop is a shift by a
2386 // constant. If it is not a shift, it pessimizes some common cases like:
2388 //void foo(int *X, int i) { X[i & 1235] = 1; }
2389 //int bar(int *X, int i) { return X[i & 255]; }
2390 SDNode *BinOpLHSVal = LHS->getOperand(0).getNode();
2391 if ((BinOpLHSVal->getOpcode() != ISD::SHL &&
2392 BinOpLHSVal->getOpcode() != ISD::SRA &&
2393 BinOpLHSVal->getOpcode() != ISD::SRL) ||
2394 !isa<ConstantSDNode>(BinOpLHSVal->getOperand(1)))
2397 MVT VT = N->getValueType(0);
2399 // If this is a signed shift right, and the high bit is modified
2400 // by the logical operation, do not perform the transformation.
2401 // The highBitSet boolean indicates the value of the high bit of
2402 // the constant which would cause it to be modified for this
2404 if (N->getOpcode() == ISD::SRA) {
2405 bool BinOpRHSSignSet = BinOpCst->getAPIntValue().isNegative();
2406 if (BinOpRHSSignSet != HighBitSet)
2410 // Fold the constants, shifting the binop RHS by the shift amount.
2411 SDValue NewRHS = DAG.getNode(N->getOpcode(), N->getValueType(0),
2412 LHS->getOperand(1), N->getOperand(1));
2414 // Create the new shift.
2415 SDValue NewShift = DAG.getNode(N->getOpcode(), VT, LHS->getOperand(0),
2418 // Create the new binop.
2419 return DAG.getNode(LHS->getOpcode(), VT, NewShift, NewRHS);
2423 SDValue DAGCombiner::visitSHL(SDNode *N) {
2424 SDValue N0 = N->getOperand(0);
2425 SDValue N1 = N->getOperand(1);
2426 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
2427 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
2428 MVT VT = N0.getValueType();
2429 unsigned OpSizeInBits = VT.getSizeInBits();
2431 // fold (shl c1, c2) -> c1<<c2
2433 return DAG.FoldConstantArithmetic(ISD::SHL, VT, N0C, N1C);
2434 // fold (shl 0, x) -> 0
2435 if (N0C && N0C->isNullValue())
2437 // fold (shl x, c >= size(x)) -> undef
2438 if (N1C && N1C->getZExtValue() >= OpSizeInBits)
2439 return DAG.getNode(ISD::UNDEF, VT);
2440 // fold (shl x, 0) -> x
2441 if (N1C && N1C->isNullValue())
2443 // if (shl x, c) is known to be zero, return 0
2444 if (DAG.MaskedValueIsZero(SDValue(N, 0),
2445 APInt::getAllOnesValue(VT.getSizeInBits())))
2446 return DAG.getConstant(0, VT);
2447 // fold (shl x, (trunc (and y, c))) -> (shl x, (and (trunc y), c))
2448 // iff (trunc c) == c
2449 if (N1.getOpcode() == ISD::TRUNCATE &&
2450 N1.getOperand(0).getOpcode() == ISD::AND &&
2451 N1.hasOneUse() && N1.getOperand(0).hasOneUse()) {
2452 SDValue N101 = N1.getOperand(0).getOperand(1);
2453 if (ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N101)) {
2454 MVT TruncVT = N1.getValueType();
2455 SDValue N100 = N1.getOperand(0).getOperand(0);
2456 uint64_t TruncC = TruncVT.getIntegerVTBitMask() &
2457 N101C->getZExtValue();
2458 return DAG.getNode(ISD::SHL, VT, N0,
2459 DAG.getNode(ISD::AND, TruncVT,
2460 DAG.getNode(ISD::TRUNCATE, TruncVT, N100),
2461 DAG.getConstant(TruncC, TruncVT)));
2465 if (N1C && SimplifyDemandedBits(SDValue(N, 0)))
2466 return SDValue(N, 0);
2467 // fold (shl (shl x, c1), c2) -> 0 or (shl x, c1+c2)
2468 if (N1C && N0.getOpcode() == ISD::SHL &&
2469 N0.getOperand(1).getOpcode() == ISD::Constant) {
2470 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue();
2471 uint64_t c2 = N1C->getZExtValue();
2472 if (c1 + c2 > OpSizeInBits)
2473 return DAG.getConstant(0, VT);
2474 return DAG.getNode(ISD::SHL, VT, N0.getOperand(0),
2475 DAG.getConstant(c1 + c2, N1.getValueType()));
2477 // fold (shl (srl x, c1), c2) -> (shl (and x, -1 << c1), c2-c1) or
2478 // (srl (and x, -1 << c1), c1-c2)
2479 if (N1C && N0.getOpcode() == ISD::SRL &&
2480 N0.getOperand(1).getOpcode() == ISD::Constant) {
2481 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue();
2482 uint64_t c2 = N1C->getZExtValue();
2483 SDValue Mask = DAG.getNode(ISD::AND, VT, N0.getOperand(0),
2484 DAG.getConstant(~0ULL << c1, VT));
2486 return DAG.getNode(ISD::SHL, VT, Mask,
2487 DAG.getConstant(c2-c1, N1.getValueType()));
2489 return DAG.getNode(ISD::SRL, VT, Mask,
2490 DAG.getConstant(c1-c2, N1.getValueType()));
2492 // fold (shl (sra x, c1), c1) -> (and x, -1 << c1)
2493 if (N1C && N0.getOpcode() == ISD::SRA && N1 == N0.getOperand(1))
2494 return DAG.getNode(ISD::AND, VT, N0.getOperand(0),
2495 DAG.getConstant(~0ULL << N1C->getZExtValue(), VT));
2497 return N1C ? visitShiftByConstant(N, N1C->getZExtValue()) : SDValue();
2500 SDValue DAGCombiner::visitSRA(SDNode *N) {
2501 SDValue N0 = N->getOperand(0);
2502 SDValue N1 = N->getOperand(1);
2503 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
2504 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
2505 MVT VT = N0.getValueType();
2507 // fold (sra c1, c2) -> c1>>c2
2509 return DAG.FoldConstantArithmetic(ISD::SRA, VT, N0C, N1C);
2510 // fold (sra 0, x) -> 0
2511 if (N0C && N0C->isNullValue())
2513 // fold (sra -1, x) -> -1
2514 if (N0C && N0C->isAllOnesValue())
2516 // fold (sra x, c >= size(x)) -> undef
2517 if (N1C && N1C->getZExtValue() >= VT.getSizeInBits())
2518 return DAG.getNode(ISD::UNDEF, VT);
2519 // fold (sra x, 0) -> x
2520 if (N1C && N1C->isNullValue())
2522 // fold (sra (shl x, c1), c1) -> sext_inreg for some c1 and target supports
2524 if (N1C && N0.getOpcode() == ISD::SHL && N1 == N0.getOperand(1)) {
2525 unsigned LowBits = VT.getSizeInBits() - (unsigned)N1C->getZExtValue();
2526 MVT EVT = MVT::getIntegerVT(LowBits);
2527 if ((!LegalOperations || TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, EVT)))
2528 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0),
2529 DAG.getValueType(EVT));
2532 // fold (sra (sra x, c1), c2) -> (sra x, c1+c2)
2533 if (N1C && N0.getOpcode() == ISD::SRA) {
2534 if (ConstantSDNode *C1 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
2535 unsigned Sum = N1C->getZExtValue() + C1->getZExtValue();
2536 if (Sum >= VT.getSizeInBits()) Sum = VT.getSizeInBits()-1;
2537 return DAG.getNode(ISD::SRA, VT, N0.getOperand(0),
2538 DAG.getConstant(Sum, N1C->getValueType(0)));
2542 // fold sra (shl X, m), result_size - n
2543 // -> (sign_extend (trunc (shl X, result_size - n - m))) for
2544 // result_size - n != m.
2545 // If truncate is free for the target sext(shl) is likely to result in better
2547 if (N0.getOpcode() == ISD::SHL) {
2548 // Get the two constanst of the shifts, CN0 = m, CN = n.
2549 const ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
2551 // Determine what the truncate's result bitsize and type would be.
2552 unsigned VTValSize = VT.getSizeInBits();
2554 MVT::getIntegerVT(VTValSize - N1C->getZExtValue());
2555 // Determine the residual right-shift amount.
2556 unsigned ShiftAmt = N1C->getZExtValue() - N01C->getZExtValue();
2558 // If the shift is not a no-op (in which case this should be just a sign
2559 // extend already), the truncated to type is legal, sign_extend is legal
2560 // on that type, and the the truncate to that type is both legal and free,
2561 // perform the transform.
2563 TLI.isOperationLegalOrCustom(ISD::SIGN_EXTEND, TruncVT) &&
2564 TLI.isOperationLegalOrCustom(ISD::TRUNCATE, VT) &&
2565 TLI.isTruncateFree(VT, TruncVT)) {
2567 SDValue Amt = DAG.getConstant(ShiftAmt, TLI.getShiftAmountTy());
2568 SDValue Shift = DAG.getNode(ISD::SRL, VT, N0.getOperand(0), Amt);
2569 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, TruncVT, Shift);
2570 return DAG.getNode(ISD::SIGN_EXTEND, N->getValueType(0), Trunc);
2575 // fold (sra x, (trunc (and y, c))) -> (sra x, (and (trunc y), c))
2576 // iff (trunc c) == c
2577 if (N1.getOpcode() == ISD::TRUNCATE &&
2578 N1.getOperand(0).getOpcode() == ISD::AND &&
2579 N1.hasOneUse() && N1.getOperand(0).hasOneUse()) {
2580 SDValue N101 = N1.getOperand(0).getOperand(1);
2581 if (ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N101)) {
2582 MVT TruncVT = N1.getValueType();
2583 SDValue N100 = N1.getOperand(0).getOperand(0);
2584 uint64_t TruncC = TruncVT.getIntegerVTBitMask() &
2585 N101C->getZExtValue();
2586 return DAG.getNode(ISD::SRA, VT, N0,
2587 DAG.getNode(ISD::AND, TruncVT,
2588 DAG.getNode(ISD::TRUNCATE, TruncVT, N100),
2589 DAG.getConstant(TruncC, TruncVT)));
2593 // Simplify, based on bits shifted out of the LHS.
2594 if (N1C && SimplifyDemandedBits(SDValue(N, 0)))
2595 return SDValue(N, 0);
2598 // If the sign bit is known to be zero, switch this to a SRL.
2599 if (DAG.SignBitIsZero(N0))
2600 return DAG.getNode(ISD::SRL, VT, N0, N1);
2602 return N1C ? visitShiftByConstant(N, N1C->getZExtValue()) : SDValue();
2605 SDValue DAGCombiner::visitSRL(SDNode *N) {
2606 SDValue N0 = N->getOperand(0);
2607 SDValue N1 = N->getOperand(1);
2608 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
2609 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
2610 MVT VT = N0.getValueType();
2611 unsigned OpSizeInBits = VT.getSizeInBits();
2613 // fold (srl c1, c2) -> c1 >>u c2
2615 return DAG.FoldConstantArithmetic(ISD::SRL, VT, N0C, N1C);
2616 // fold (srl 0, x) -> 0
2617 if (N0C && N0C->isNullValue())
2619 // fold (srl x, c >= size(x)) -> undef
2620 if (N1C && N1C->getZExtValue() >= OpSizeInBits)
2621 return DAG.getNode(ISD::UNDEF, VT);
2622 // fold (srl x, 0) -> x
2623 if (N1C && N1C->isNullValue())
2625 // if (srl x, c) is known to be zero, return 0
2626 if (N1C && DAG.MaskedValueIsZero(SDValue(N, 0),
2627 APInt::getAllOnesValue(OpSizeInBits)))
2628 return DAG.getConstant(0, VT);
2630 // fold (srl (srl x, c1), c2) -> 0 or (srl x, c1+c2)
2631 if (N1C && N0.getOpcode() == ISD::SRL &&
2632 N0.getOperand(1).getOpcode() == ISD::Constant) {
2633 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue();
2634 uint64_t c2 = N1C->getZExtValue();
2635 if (c1 + c2 > OpSizeInBits)
2636 return DAG.getConstant(0, VT);
2637 return DAG.getNode(ISD::SRL, VT, N0.getOperand(0),
2638 DAG.getConstant(c1 + c2, N1.getValueType()));
2641 // fold (srl (anyextend x), c) -> (anyextend (srl x, c))
2642 if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) {
2643 // Shifting in all undef bits?
2644 MVT SmallVT = N0.getOperand(0).getValueType();
2645 if (N1C->getZExtValue() >= SmallVT.getSizeInBits())
2646 return DAG.getNode(ISD::UNDEF, VT);
2648 SDValue SmallShift = DAG.getNode(ISD::SRL, SmallVT, N0.getOperand(0), N1);
2649 AddToWorkList(SmallShift.getNode());
2650 return DAG.getNode(ISD::ANY_EXTEND, VT, SmallShift);
2653 // fold (srl (sra X, Y), 31) -> (srl X, 31). This srl only looks at the sign
2654 // bit, which is unmodified by sra.
2655 if (N1C && N1C->getZExtValue()+1 == VT.getSizeInBits()) {
2656 if (N0.getOpcode() == ISD::SRA)
2657 return DAG.getNode(ISD::SRL, VT, N0.getOperand(0), N1);
2660 // fold (srl (ctlz x), "5") -> x iff x has one bit set (the low bit).
2661 if (N1C && N0.getOpcode() == ISD::CTLZ &&
2662 N1C->getAPIntValue() == Log2_32(VT.getSizeInBits())) {
2663 APInt KnownZero, KnownOne;
2664 APInt Mask = APInt::getAllOnesValue(VT.getSizeInBits());
2665 DAG.ComputeMaskedBits(N0.getOperand(0), Mask, KnownZero, KnownOne);
2667 // If any of the input bits are KnownOne, then the input couldn't be all
2668 // zeros, thus the result of the srl will always be zero.
2669 if (KnownOne.getBoolValue()) return DAG.getConstant(0, VT);
2671 // If all of the bits input the to ctlz node are known to be zero, then
2672 // the result of the ctlz is "32" and the result of the shift is one.
2673 APInt UnknownBits = ~KnownZero & Mask;
2674 if (UnknownBits == 0) return DAG.getConstant(1, VT);
2676 // Otherwise, check to see if there is exactly one bit input to the ctlz.
2677 if ((UnknownBits & (UnknownBits-1)) == 0) {
2678 // Okay, we know that only that the single bit specified by UnknownBits
2679 // could be set on input to the CTLZ node. If this bit is set, the SRL
2680 // will return 0, if it is clear, it returns 1. Change the CTLZ/SRL pair
2681 // to an SRL,XOR pair, which is likely to simplify more.
2682 unsigned ShAmt = UnknownBits.countTrailingZeros();
2683 SDValue Op = N0.getOperand(0);
2685 Op = DAG.getNode(ISD::SRL, VT, Op,
2686 DAG.getConstant(ShAmt, TLI.getShiftAmountTy()));
2687 AddToWorkList(Op.getNode());
2689 return DAG.getNode(ISD::XOR, VT, Op, DAG.getConstant(1, VT));
2693 // fold (srl x, (trunc (and y, c))) -> (srl x, (and (trunc y), c))
2694 // iff (trunc c) == c
2695 if (N1.getOpcode() == ISD::TRUNCATE &&
2696 N1.getOperand(0).getOpcode() == ISD::AND &&
2697 N1.hasOneUse() && N1.getOperand(0).hasOneUse()) {
2698 SDValue N101 = N1.getOperand(0).getOperand(1);
2699 if (ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N101)) {
2700 MVT TruncVT = N1.getValueType();
2701 SDValue N100 = N1.getOperand(0).getOperand(0);
2702 uint64_t TruncC = TruncVT.getIntegerVTBitMask() &
2703 N101C->getZExtValue();
2704 return DAG.getNode(ISD::SRL, VT, N0,
2705 DAG.getNode(ISD::AND, TruncVT,
2706 DAG.getNode(ISD::TRUNCATE, TruncVT, N100),
2707 DAG.getConstant(TruncC, TruncVT)));
2711 // fold operands of srl based on knowledge that the low bits are not
2713 if (N1C && SimplifyDemandedBits(SDValue(N, 0)))
2714 return SDValue(N, 0);
2716 return N1C ? visitShiftByConstant(N, N1C->getZExtValue()) : SDValue();
2719 SDValue DAGCombiner::visitCTLZ(SDNode *N) {
2720 SDValue N0 = N->getOperand(0);
2721 MVT VT = N->getValueType(0);
2723 // fold (ctlz c1) -> c2
2724 if (isa<ConstantSDNode>(N0))
2725 return DAG.getNode(ISD::CTLZ, VT, N0);
2729 SDValue DAGCombiner::visitCTTZ(SDNode *N) {
2730 SDValue N0 = N->getOperand(0);
2731 MVT VT = N->getValueType(0);
2733 // fold (cttz c1) -> c2
2734 if (isa<ConstantSDNode>(N0))
2735 return DAG.getNode(ISD::CTTZ, VT, N0);
2739 SDValue DAGCombiner::visitCTPOP(SDNode *N) {
2740 SDValue N0 = N->getOperand(0);
2741 MVT VT = N->getValueType(0);
2743 // fold (ctpop c1) -> c2
2744 if (isa<ConstantSDNode>(N0))
2745 return DAG.getNode(ISD::CTPOP, VT, N0);
2749 SDValue DAGCombiner::visitSELECT(SDNode *N) {
2750 SDValue N0 = N->getOperand(0);
2751 SDValue N1 = N->getOperand(1);
2752 SDValue N2 = N->getOperand(2);
2753 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
2754 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
2755 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2);
2756 MVT VT = N->getValueType(0);
2757 MVT VT0 = N0.getValueType();
2759 // fold select C, X, X -> X
2762 // fold select true, X, Y -> X
2763 if (N0C && !N0C->isNullValue())
2765 // fold select false, X, Y -> Y
2766 if (N0C && N0C->isNullValue())
2768 // fold select C, 1, X -> C | X
2769 if (VT == MVT::i1 && N1C && N1C->getAPIntValue() == 1)
2770 return DAG.getNode(ISD::OR, VT, N0, N2);
2771 // fold select C, 0, 1 -> C ^ 1
2772 if (VT.isInteger() &&
2775 TLI.getBooleanContents() == TargetLowering::ZeroOrOneBooleanContent)) &&
2776 N1C && N2C && N1C->isNullValue() && N2C->getAPIntValue() == 1) {
2777 SDValue XORNode = DAG.getNode(ISD::XOR, VT0, N0, DAG.getConstant(1, VT0));
2780 AddToWorkList(XORNode.getNode());
2782 return DAG.getNode(ISD::ZERO_EXTEND, VT, XORNode);
2783 return DAG.getNode(ISD::TRUNCATE, VT, XORNode);
2785 // fold select C, 0, X -> ~C & X
2786 if (VT == VT0 && VT == MVT::i1 && N1C && N1C->isNullValue()) {
2787 SDValue NOTNode = DAG.getNOT(N0, VT);
2788 AddToWorkList(NOTNode.getNode());
2789 return DAG.getNode(ISD::AND, VT, NOTNode, N2);
2791 // fold select C, X, 1 -> ~C | X
2792 if (VT == VT0 && VT == MVT::i1 && N2C && N2C->getAPIntValue() == 1) {
2793 SDValue NOTNode = DAG.getNOT(N0, VT);
2794 AddToWorkList(NOTNode.getNode());
2795 return DAG.getNode(ISD::OR, VT, NOTNode, N1);
2797 // fold select C, X, 0 -> C & X
2798 if (VT == MVT::i1 && N2C && N2C->isNullValue())
2799 return DAG.getNode(ISD::AND, VT, N0, N1);
2800 // fold X ? X : Y --> X ? 1 : Y --> X | Y
2801 if (VT == MVT::i1 && N0 == N1)
2802 return DAG.getNode(ISD::OR, VT, N0, N2);
2803 // fold X ? Y : X --> X ? Y : 0 --> X & Y
2804 if (VT == MVT::i1 && N0 == N2)
2805 return DAG.getNode(ISD::AND, VT, N0, N1);
2807 // If we can fold this based on the true/false value, do so.
2808 if (SimplifySelectOps(N, N1, N2))
2809 return SDValue(N, 0); // Don't revisit N.
2811 // fold selects based on a setcc into other things, such as min/max/abs
2812 if (N0.getOpcode() == ISD::SETCC) {
2814 // Check against MVT::Other for SELECT_CC, which is a workaround for targets
2815 // having to say they don't support SELECT_CC on every type the DAG knows
2816 // about, since there is no way to mark an opcode illegal at all value types
2817 if (TLI.isOperationLegalOrCustom(ISD::SELECT_CC, MVT::Other))
2818 return DAG.getNode(ISD::SELECT_CC, VT, N0.getOperand(0), N0.getOperand(1),
2819 N1, N2, N0.getOperand(2));
2821 return SimplifySelect(N0, N1, N2);
2826 SDValue DAGCombiner::visitSELECT_CC(SDNode *N) {
2827 SDValue N0 = N->getOperand(0);
2828 SDValue N1 = N->getOperand(1);
2829 SDValue N2 = N->getOperand(2);
2830 SDValue N3 = N->getOperand(3);
2831 SDValue N4 = N->getOperand(4);
2832 ISD::CondCode CC = cast<CondCodeSDNode>(N4)->get();
2834 // fold select_cc lhs, rhs, x, x, cc -> x
2838 // Determine if the condition we're dealing with is constant
2839 SDValue SCC = SimplifySetCC(TLI.getSetCCResultType(N0.getValueType()),
2841 if (SCC.getNode()) AddToWorkList(SCC.getNode());
2843 if (ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.getNode())) {
2844 if (!SCCC->isNullValue())
2845 return N2; // cond always true -> true val
2847 return N3; // cond always false -> false val
2850 // Fold to a simpler select_cc
2851 if (SCC.getNode() && SCC.getOpcode() == ISD::SETCC)
2852 return DAG.getNode(ISD::SELECT_CC, N2.getValueType(),
2853 SCC.getOperand(0), SCC.getOperand(1), N2, N3,
2856 // If we can fold this based on the true/false value, do so.
2857 if (SimplifySelectOps(N, N2, N3))
2858 return SDValue(N, 0); // Don't revisit N.
2860 // fold select_cc into other things, such as min/max/abs
2861 return SimplifySelectCC(N0, N1, N2, N3, CC);
2864 SDValue DAGCombiner::visitSETCC(SDNode *N) {
2865 return SimplifySetCC(N->getValueType(0), N->getOperand(0), N->getOperand(1),
2866 cast<CondCodeSDNode>(N->getOperand(2))->get());
2869 // ExtendUsesToFormExtLoad - Trying to extend uses of a load to enable this:
2870 // "fold ({s|z}ext (load x)) -> ({s|z}ext (truncate ({s|z}extload x)))"
2871 // transformation. Returns true if extension are possible and the above
2872 // mentioned transformation is profitable.
2873 static bool ExtendUsesToFormExtLoad(SDNode *N, SDValue N0,
2875 SmallVector<SDNode*, 4> &ExtendNodes,
2876 const TargetLowering &TLI) {
2877 bool HasCopyToRegUses = false;
2878 bool isTruncFree = TLI.isTruncateFree(N->getValueType(0), N0.getValueType());
2879 for (SDNode::use_iterator UI = N0.getNode()->use_begin(),
2880 UE = N0.getNode()->use_end();
2885 // FIXME: Only extend SETCC N, N and SETCC N, c for now.
2886 if (User->getOpcode() == ISD::SETCC) {
2887 ISD::CondCode CC = cast<CondCodeSDNode>(User->getOperand(2))->get();
2888 if (ExtOpc == ISD::ZERO_EXTEND && ISD::isSignedIntSetCC(CC))
2889 // Sign bits will be lost after a zext.
2892 for (unsigned i = 0; i != 2; ++i) {
2893 SDValue UseOp = User->getOperand(i);
2896 if (!isa<ConstantSDNode>(UseOp))
2901 ExtendNodes.push_back(User);
2903 for (unsigned i = 0, e = User->getNumOperands(); i != e; ++i) {
2904 SDValue UseOp = User->getOperand(i);
2906 // If truncate from extended type to original load type is free
2907 // on this target, then it's ok to extend a CopyToReg.
2908 if (isTruncFree && User->getOpcode() == ISD::CopyToReg)
2909 HasCopyToRegUses = true;
2917 if (HasCopyToRegUses) {
2918 bool BothLiveOut = false;
2919 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end();
2922 for (unsigned i = 0, e = User->getNumOperands(); i != e; ++i) {
2923 SDValue UseOp = User->getOperand(i);
2924 if (UseOp.getNode() == N && UseOp.getResNo() == 0) {
2931 // Both unextended and extended values are live out. There had better be
2932 // good a reason for the transformation.
2933 return ExtendNodes.size();
2938 SDValue DAGCombiner::visitSIGN_EXTEND(SDNode *N) {
2939 SDValue N0 = N->getOperand(0);
2940 MVT VT = N->getValueType(0);
2942 // fold (sext c1) -> c1
2943 if (isa<ConstantSDNode>(N0))
2944 return DAG.getNode(ISD::SIGN_EXTEND, VT, N0);
2946 // fold (sext (sext x)) -> (sext x)
2947 // fold (sext (aext x)) -> (sext x)
2948 if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND)
2949 return DAG.getNode(ISD::SIGN_EXTEND, VT, N0.getOperand(0));
2951 if (N0.getOpcode() == ISD::TRUNCATE) {
2952 // fold (sext (truncate (load x))) -> (sext (smaller load x))
2953 // fold (sext (truncate (srl (load x), c))) -> (sext (smaller load (x+c/n)))
2954 SDValue NarrowLoad = ReduceLoadWidth(N0.getNode());
2955 if (NarrowLoad.getNode()) {
2956 if (NarrowLoad.getNode() != N0.getNode())
2957 CombineTo(N0.getNode(), NarrowLoad);
2958 return DAG.getNode(ISD::SIGN_EXTEND, VT, NarrowLoad);
2961 // See if the value being truncated is already sign extended. If so, just
2962 // eliminate the trunc/sext pair.
2963 SDValue Op = N0.getOperand(0);
2964 unsigned OpBits = Op.getValueType().getSizeInBits();
2965 unsigned MidBits = N0.getValueType().getSizeInBits();
2966 unsigned DestBits = VT.getSizeInBits();
2967 unsigned NumSignBits = DAG.ComputeNumSignBits(Op);
2969 if (OpBits == DestBits) {
2970 // Op is i32, Mid is i8, and Dest is i32. If Op has more than 24 sign
2971 // bits, it is already ready.
2972 if (NumSignBits > DestBits-MidBits)
2974 } else if (OpBits < DestBits) {
2975 // Op is i32, Mid is i8, and Dest is i64. If Op has more than 24 sign
2976 // bits, just sext from i32.
2977 if (NumSignBits > OpBits-MidBits)
2978 return DAG.getNode(ISD::SIGN_EXTEND, VT, Op);
2980 // Op is i64, Mid is i8, and Dest is i32. If Op has more than 56 sign
2981 // bits, just truncate to i32.
2982 if (NumSignBits > OpBits-MidBits)
2983 return DAG.getNode(ISD::TRUNCATE, VT, Op);
2986 // fold (sext (truncate x)) -> (sextinreg x).
2987 if (!LegalOperations || TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG,
2988 N0.getValueType())) {
2989 if (Op.getValueType().bitsLT(VT))
2990 Op = DAG.getNode(ISD::ANY_EXTEND, VT, Op);
2991 else if (Op.getValueType().bitsGT(VT))
2992 Op = DAG.getNode(ISD::TRUNCATE, VT, Op);
2993 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, Op,
2994 DAG.getValueType(N0.getValueType()));
2998 // fold (sext (load x)) -> (sext (truncate (sextload x)))
2999 if (ISD::isNON_EXTLoad(N0.getNode()) &&
3000 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
3001 TLI.isLoadExtLegal(ISD::SEXTLOAD, N0.getValueType()))) {
3002 bool DoXform = true;
3003 SmallVector<SDNode*, 4> SetCCs;
3004 if (!N0.hasOneUse())
3005 DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::SIGN_EXTEND, SetCCs, TLI);
3007 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
3008 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, LN0->getChain(),
3009 LN0->getBasePtr(), LN0->getSrcValue(),
3010 LN0->getSrcValueOffset(),
3012 LN0->isVolatile(), LN0->getAlignment());
3013 CombineTo(N, ExtLoad);
3014 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad);
3015 CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1));
3016 // Extend SetCC uses if necessary.
3017 for (unsigned i = 0, e = SetCCs.size(); i != e; ++i) {
3018 SDNode *SetCC = SetCCs[i];
3019 SmallVector<SDValue, 4> Ops;
3020 for (unsigned j = 0; j != 2; ++j) {
3021 SDValue SOp = SetCC->getOperand(j);
3023 Ops.push_back(ExtLoad);
3025 Ops.push_back(DAG.getNode(ISD::SIGN_EXTEND, VT, SOp));
3027 Ops.push_back(SetCC->getOperand(2));
3028 CombineTo(SetCC, DAG.getNode(ISD::SETCC, SetCC->getValueType(0),
3029 &Ops[0], Ops.size()));
3031 return SDValue(N, 0); // Return N so it doesn't get rechecked!
3035 // fold (sext (sextload x)) -> (sext (truncate (sextload x)))
3036 // fold (sext ( extload x)) -> (sext (truncate (sextload x)))
3037 if ((ISD::isSEXTLoad(N0.getNode()) || ISD::isEXTLoad(N0.getNode())) &&
3038 ISD::isUNINDEXEDLoad(N0.getNode()) && N0.hasOneUse()) {
3039 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
3040 MVT EVT = LN0->getMemoryVT();
3041 if ((!LegalOperations && !LN0->isVolatile()) ||
3042 TLI.isLoadExtLegal(ISD::SEXTLOAD, EVT)) {
3043 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, LN0->getChain(),
3044 LN0->getBasePtr(), LN0->getSrcValue(),
3045 LN0->getSrcValueOffset(), EVT,
3046 LN0->isVolatile(), LN0->getAlignment());
3047 CombineTo(N, ExtLoad);
3048 CombineTo(N0.getNode(),
3049 DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
3050 ExtLoad.getValue(1));
3051 return SDValue(N, 0); // Return N so it doesn't get rechecked!
3055 // sext(setcc x,y,cc) -> select_cc x, y, -1, 0, cc
3056 if (N0.getOpcode() == ISD::SETCC) {
3058 SimplifySelectCC(N0.getOperand(0), N0.getOperand(1),
3059 DAG.getConstant(~0ULL, VT), DAG.getConstant(0, VT),
3060 cast<CondCodeSDNode>(N0.getOperand(2))->get(), true);
3061 if (SCC.getNode()) return SCC;
3064 // fold (sext x) -> (zext x) if the sign bit is known zero.
3065 if ((!LegalOperations || TLI.isOperationLegal(ISD::ZERO_EXTEND, VT)) &&
3066 DAG.SignBitIsZero(N0))
3067 return DAG.getNode(ISD::ZERO_EXTEND, VT, N0);
3072 SDValue DAGCombiner::visitZERO_EXTEND(SDNode *N) {
3073 SDValue N0 = N->getOperand(0);
3074 MVT VT = N->getValueType(0);
3076 // fold (zext c1) -> c1
3077 if (isa<ConstantSDNode>(N0))
3078 return DAG.getNode(ISD::ZERO_EXTEND, VT, N0);
3079 // fold (zext (zext x)) -> (zext x)
3080 // fold (zext (aext x)) -> (zext x)
3081 if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND)
3082 return DAG.getNode(ISD::ZERO_EXTEND, VT, N0.getOperand(0));
3084 // fold (zext (truncate (load x))) -> (zext (smaller load x))
3085 // fold (zext (truncate (srl (load x), c))) -> (zext (small load (x+c/n)))
3086 if (N0.getOpcode() == ISD::TRUNCATE) {
3087 SDValue NarrowLoad = ReduceLoadWidth(N0.getNode());
3088 if (NarrowLoad.getNode()) {
3089 if (NarrowLoad.getNode() != N0.getNode())
3090 CombineTo(N0.getNode(), NarrowLoad);
3091 return DAG.getNode(ISD::ZERO_EXTEND, VT, NarrowLoad);
3095 // fold (zext (truncate x)) -> (and x, mask)
3096 if (N0.getOpcode() == ISD::TRUNCATE &&
3097 (!LegalOperations || TLI.isOperationLegal(ISD::AND, VT))) {
3098 SDValue Op = N0.getOperand(0);
3099 if (Op.getValueType().bitsLT(VT)) {
3100 Op = DAG.getNode(ISD::ANY_EXTEND, VT, Op);
3101 } else if (Op.getValueType().bitsGT(VT)) {
3102 Op = DAG.getNode(ISD::TRUNCATE, VT, Op);
3104 return DAG.getZeroExtendInReg(Op, N0.getValueType());
3107 // fold (zext (and (trunc x), cst)) -> (and x, cst).
3108 if (N0.getOpcode() == ISD::AND &&
3109 N0.getOperand(0).getOpcode() == ISD::TRUNCATE &&
3110 N0.getOperand(1).getOpcode() == ISD::Constant) {
3111 SDValue X = N0.getOperand(0).getOperand(0);
3112 if (X.getValueType().bitsLT(VT)) {
3113 X = DAG.getNode(ISD::ANY_EXTEND, VT, X);
3114 } else if (X.getValueType().bitsGT(VT)) {
3115 X = DAG.getNode(ISD::TRUNCATE, VT, X);
3117 APInt Mask = cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue();
3118 Mask.zext(VT.getSizeInBits());
3119 return DAG.getNode(ISD::AND, VT, X, DAG.getConstant(Mask, VT));
3122 // fold (zext (load x)) -> (zext (truncate (zextload x)))
3123 if (ISD::isNON_EXTLoad(N0.getNode()) &&
3124 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
3125 TLI.isLoadExtLegal(ISD::ZEXTLOAD, N0.getValueType()))) {
3126 bool DoXform = true;
3127 SmallVector<SDNode*, 4> SetCCs;
3128 if (!N0.hasOneUse())
3129 DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::ZERO_EXTEND, SetCCs, TLI);
3131 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
3132 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, LN0->getChain(),
3133 LN0->getBasePtr(), LN0->getSrcValue(),
3134 LN0->getSrcValueOffset(),
3136 LN0->isVolatile(), LN0->getAlignment());
3137 CombineTo(N, ExtLoad);
3138 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad);
3139 CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1));
3140 // Extend SetCC uses if necessary.
3141 for (unsigned i = 0, e = SetCCs.size(); i != e; ++i) {
3142 SDNode *SetCC = SetCCs[i];
3143 SmallVector<SDValue, 4> Ops;
3144 for (unsigned j = 0; j != 2; ++j) {
3145 SDValue SOp = SetCC->getOperand(j);
3147 Ops.push_back(ExtLoad);
3149 Ops.push_back(DAG.getNode(ISD::ZERO_EXTEND, VT, SOp));
3151 Ops.push_back(SetCC->getOperand(2));
3152 CombineTo(SetCC, DAG.getNode(ISD::SETCC, SetCC->getValueType(0),
3153 &Ops[0], Ops.size()));
3155 return SDValue(N, 0); // Return N so it doesn't get rechecked!
3159 // fold (zext (zextload x)) -> (zext (truncate (zextload x)))
3160 // fold (zext ( extload x)) -> (zext (truncate (zextload x)))
3161 if ((ISD::isZEXTLoad(N0.getNode()) || ISD::isEXTLoad(N0.getNode())) &&
3162 ISD::isUNINDEXEDLoad(N0.getNode()) && N0.hasOneUse()) {
3163 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
3164 MVT EVT = LN0->getMemoryVT();
3165 if ((!LegalOperations && !LN0->isVolatile()) ||
3166 TLI.isLoadExtLegal(ISD::ZEXTLOAD, EVT)) {
3167 SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, LN0->getChain(),
3168 LN0->getBasePtr(), LN0->getSrcValue(),
3169 LN0->getSrcValueOffset(), EVT,
3170 LN0->isVolatile(), LN0->getAlignment());
3171 CombineTo(N, ExtLoad);
3172 CombineTo(N0.getNode(),
3173 DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
3174 ExtLoad.getValue(1));
3175 return SDValue(N, 0); // Return N so it doesn't get rechecked!
3179 // zext(setcc x,y,cc) -> select_cc x, y, 1, 0, cc
3180 if (N0.getOpcode() == ISD::SETCC) {
3182 SimplifySelectCC(N0.getOperand(0), N0.getOperand(1),
3183 DAG.getConstant(1, VT), DAG.getConstant(0, VT),
3184 cast<CondCodeSDNode>(N0.getOperand(2))->get(), true);
3185 if (SCC.getNode()) return SCC;
3191 SDValue DAGCombiner::visitANY_EXTEND(SDNode *N) {
3192 SDValue N0 = N->getOperand(0);
3193 MVT VT = N->getValueType(0);
3195 // fold (aext c1) -> c1
3196 if (isa<ConstantSDNode>(N0))
3197 return DAG.getNode(ISD::ANY_EXTEND, VT, N0);
3198 // fold (aext (aext x)) -> (aext x)
3199 // fold (aext (zext x)) -> (zext x)
3200 // fold (aext (sext x)) -> (sext x)
3201 if (N0.getOpcode() == ISD::ANY_EXTEND ||
3202 N0.getOpcode() == ISD::ZERO_EXTEND ||
3203 N0.getOpcode() == ISD::SIGN_EXTEND)
3204 return DAG.getNode(N0.getOpcode(), VT, N0.getOperand(0));
3206 // fold (aext (truncate (load x))) -> (aext (smaller load x))
3207 // fold (aext (truncate (srl (load x), c))) -> (aext (small load (x+c/n)))
3208 if (N0.getOpcode() == ISD::TRUNCATE) {
3209 SDValue NarrowLoad = ReduceLoadWidth(N0.getNode());
3210 if (NarrowLoad.getNode()) {
3211 if (NarrowLoad.getNode() != N0.getNode())
3212 CombineTo(N0.getNode(), NarrowLoad);
3213 return DAG.getNode(ISD::ANY_EXTEND, VT, NarrowLoad);
3217 // fold (aext (truncate x))
3218 if (N0.getOpcode() == ISD::TRUNCATE) {
3219 SDValue TruncOp = N0.getOperand(0);
3220 if (TruncOp.getValueType() == VT)
3221 return TruncOp; // x iff x size == zext size.
3222 if (TruncOp.getValueType().bitsGT(VT))
3223 return DAG.getNode(ISD::TRUNCATE, VT, TruncOp);
3224 return DAG.getNode(ISD::ANY_EXTEND, VT, TruncOp);
3227 // fold (aext (and (trunc x), cst)) -> (and x, cst).
3228 if (N0.getOpcode() == ISD::AND &&
3229 N0.getOperand(0).getOpcode() == ISD::TRUNCATE &&
3230 N0.getOperand(1).getOpcode() == ISD::Constant) {
3231 SDValue X = N0.getOperand(0).getOperand(0);
3232 if (X.getValueType().bitsLT(VT)) {
3233 X = DAG.getNode(ISD::ANY_EXTEND, VT, X);
3234 } else if (X.getValueType().bitsGT(VT)) {
3235 X = DAG.getNode(ISD::TRUNCATE, VT, X);
3237 APInt Mask = cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue();
3238 Mask.zext(VT.getSizeInBits());
3239 return DAG.getNode(ISD::AND, VT, X, DAG.getConstant(Mask, VT));
3242 // fold (aext (load x)) -> (aext (truncate (extload x)))
3243 if (ISD::isNON_EXTLoad(N0.getNode()) && N0.hasOneUse() &&
3244 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
3245 TLI.isLoadExtLegal(ISD::EXTLOAD, N0.getValueType()))) {
3246 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
3247 SDValue ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, VT, LN0->getChain(),
3248 LN0->getBasePtr(), LN0->getSrcValue(),
3249 LN0->getSrcValueOffset(),
3251 LN0->isVolatile(), LN0->getAlignment());
3252 CombineTo(N, ExtLoad);
3253 // Redirect any chain users to the new load.
3254 DAG.ReplaceAllUsesOfValueWith(SDValue(LN0, 1),
3255 SDValue(ExtLoad.getNode(), 1));
3256 // If any node needs the original loaded value, recompute it.
3257 if (!LN0->use_empty())
3258 CombineTo(LN0, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
3259 ExtLoad.getValue(1));
3260 return SDValue(N, 0); // Return N so it doesn't get rechecked!
3263 // fold (aext (zextload x)) -> (aext (truncate (zextload x)))
3264 // fold (aext (sextload x)) -> (aext (truncate (sextload x)))
3265 // fold (aext ( extload x)) -> (aext (truncate (extload x)))
3266 if (N0.getOpcode() == ISD::LOAD &&
3267 !ISD::isNON_EXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) &&
3269 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
3270 MVT EVT = LN0->getMemoryVT();
3271 SDValue ExtLoad = DAG.getExtLoad(LN0->getExtensionType(), VT,
3272 LN0->getChain(), LN0->getBasePtr(),
3274 LN0->getSrcValueOffset(), EVT,
3275 LN0->isVolatile(), LN0->getAlignment());
3276 CombineTo(N, ExtLoad);
3277 CombineTo(N0.getNode(),
3278 DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
3279 ExtLoad.getValue(1));
3280 return SDValue(N, 0); // Return N so it doesn't get rechecked!
3283 // aext(setcc x,y,cc) -> select_cc x, y, 1, 0, cc
3284 if (N0.getOpcode() == ISD::SETCC) {
3286 SimplifySelectCC(N0.getOperand(0), N0.getOperand(1),
3287 DAG.getConstant(1, VT), DAG.getConstant(0, VT),
3288 cast<CondCodeSDNode>(N0.getOperand(2))->get(), true);
3296 /// GetDemandedBits - See if the specified operand can be simplified with the
3297 /// knowledge that only the bits specified by Mask are used. If so, return the
3298 /// simpler operand, otherwise return a null SDValue.
3299 SDValue DAGCombiner::GetDemandedBits(SDValue V, const APInt &Mask) {
3300 switch (V.getOpcode()) {
3304 // If the LHS or RHS don't contribute bits to the or, drop them.
3305 if (DAG.MaskedValueIsZero(V.getOperand(0), Mask))
3306 return V.getOperand(1);
3307 if (DAG.MaskedValueIsZero(V.getOperand(1), Mask))
3308 return V.getOperand(0);
3311 // Only look at single-use SRLs.
3312 if (!V.getNode()->hasOneUse())
3314 if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(V.getOperand(1))) {
3315 // See if we can recursively simplify the LHS.
3316 unsigned Amt = RHSC->getZExtValue();
3317 // Watch out for shift count overflow though.
3318 if (Amt >= Mask.getBitWidth()) break;
3319 APInt NewMask = Mask << Amt;
3320 SDValue SimplifyLHS = GetDemandedBits(V.getOperand(0), NewMask);
3321 if (SimplifyLHS.getNode()) {
3322 return DAG.getNode(ISD::SRL, V.getValueType(),
3323 SimplifyLHS, V.getOperand(1));
3330 /// ReduceLoadWidth - If the result of a wider load is shifted to right of N
3331 /// bits and then truncated to a narrower type and where N is a multiple
3332 /// of number of bits of the narrower type, transform it to a narrower load
3333 /// from address + N / num of bits of new type. If the result is to be
3334 /// extended, also fold the extension to form a extending load.
3335 SDValue DAGCombiner::ReduceLoadWidth(SDNode *N) {
3336 unsigned Opc = N->getOpcode();
3337 ISD::LoadExtType ExtType = ISD::NON_EXTLOAD;
3338 SDValue N0 = N->getOperand(0);
3339 MVT VT = N->getValueType(0);
3342 // This transformation isn't valid for vector loads.
3346 // Special case: SIGN_EXTEND_INREG is basically truncating to EVT then
3348 if (Opc == ISD::SIGN_EXTEND_INREG) {
3349 ExtType = ISD::SEXTLOAD;
3350 EVT = cast<VTSDNode>(N->getOperand(1))->getVT();
3351 if (LegalOperations && !TLI.isLoadExtLegal(ISD::SEXTLOAD, EVT))
3355 unsigned EVTBits = EVT.getSizeInBits();
3357 if (N0.getOpcode() == ISD::SRL && N0.hasOneUse()) {
3358 if (ConstantSDNode *N01 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
3359 ShAmt = N01->getZExtValue();
3360 // Is the shift amount a multiple of size of VT?
3361 if ((ShAmt & (EVTBits-1)) == 0) {
3362 N0 = N0.getOperand(0);
3363 if (N0.getValueType().getSizeInBits() <= EVTBits)
3369 // Do not generate loads of non-round integer types since these can
3370 // be expensive (and would be wrong if the type is not byte sized).
3371 if (isa<LoadSDNode>(N0) && N0.hasOneUse() && EVT.isRound() &&
3372 cast<LoadSDNode>(N0)->getMemoryVT().getSizeInBits() > EVTBits &&
3373 // Do not change the width of a volatile load.
3374 !cast<LoadSDNode>(N0)->isVolatile()) {
3375 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
3376 MVT PtrType = N0.getOperand(1).getValueType();
3377 // For big endian targets, we need to adjust the offset to the pointer to
3378 // load the correct bytes.
3379 if (TLI.isBigEndian()) {
3380 unsigned LVTStoreBits = LN0->getMemoryVT().getStoreSizeInBits();
3381 unsigned EVTStoreBits = EVT.getStoreSizeInBits();
3382 ShAmt = LVTStoreBits - EVTStoreBits - ShAmt;
3384 uint64_t PtrOff = ShAmt / 8;
3385 unsigned NewAlign = MinAlign(LN0->getAlignment(), PtrOff);
3386 SDValue NewPtr = DAG.getNode(ISD::ADD, PtrType, LN0->getBasePtr(),
3387 DAG.getConstant(PtrOff, PtrType));
3388 AddToWorkList(NewPtr.getNode());
3389 SDValue Load = (ExtType == ISD::NON_EXTLOAD)
3390 ? DAG.getLoad(VT, LN0->getChain(), NewPtr,
3391 LN0->getSrcValue(), LN0->getSrcValueOffset() + PtrOff,
3392 LN0->isVolatile(), NewAlign)
3393 : DAG.getExtLoad(ExtType, VT, LN0->getChain(), NewPtr,
3394 LN0->getSrcValue(), LN0->getSrcValueOffset() + PtrOff,
3395 EVT, LN0->isVolatile(), NewAlign);
3396 // Replace the old load's chain with the new load's chain.
3397 WorkListRemover DeadNodes(*this);
3398 DAG.ReplaceAllUsesOfValueWith(N0.getValue(1), Load.getValue(1),
3400 // Return the new loaded value.
3408 SDValue DAGCombiner::visitSIGN_EXTEND_INREG(SDNode *N) {
3409 SDValue N0 = N->getOperand(0);
3410 SDValue N1 = N->getOperand(1);
3411 MVT VT = N->getValueType(0);
3412 MVT EVT = cast<VTSDNode>(N1)->getVT();
3413 unsigned VTBits = VT.getSizeInBits();
3414 unsigned EVTBits = EVT.getSizeInBits();
3416 // fold (sext_in_reg c1) -> c1
3417 if (isa<ConstantSDNode>(N0) || N0.getOpcode() == ISD::UNDEF)
3418 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0, N1);
3420 // If the input is already sign extended, just drop the extension.
3421 if (DAG.ComputeNumSignBits(N0) >= VT.getSizeInBits()-EVTBits+1)
3424 // fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt2
3425 if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
3426 EVT.bitsLT(cast<VTSDNode>(N0.getOperand(1))->getVT())) {
3427 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0), N1);
3430 // fold (sext_in_reg (sext x)) -> (sext x)
3431 // fold (sext_in_reg (aext x)) -> (sext x)
3432 // if x is small enough.
3433 if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) {
3434 SDValue N00 = N0.getOperand(0);
3435 if (N00.getValueType().getSizeInBits() < EVTBits)
3436 return DAG.getNode(ISD::SIGN_EXTEND, VT, N00, N1);
3439 // fold (sext_in_reg x) -> (zext_in_reg x) if the sign bit is known zero.
3440 if (DAG.MaskedValueIsZero(N0, APInt::getBitsSet(VTBits, EVTBits-1, EVTBits)))
3441 return DAG.getZeroExtendInReg(N0, EVT);
3443 // fold operands of sext_in_reg based on knowledge that the top bits are not
3445 if (SimplifyDemandedBits(SDValue(N, 0)))
3446 return SDValue(N, 0);
3448 // fold (sext_in_reg (load x)) -> (smaller sextload x)
3449 // fold (sext_in_reg (srl (load x), c)) -> (smaller sextload (x+c/evtbits))
3450 SDValue NarrowLoad = ReduceLoadWidth(N);
3451 if (NarrowLoad.getNode())
3454 // fold (sext_in_reg (srl X, 24), i8) -> sra X, 24
3455 // fold (sext_in_reg (srl X, 23), i8) -> sra X, 23 iff possible.
3456 // We already fold "(sext_in_reg (srl X, 25), i8) -> srl X, 25" above.
3457 if (N0.getOpcode() == ISD::SRL) {
3458 if (ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(N0.getOperand(1)))
3459 if (ShAmt->getZExtValue()+EVTBits <= VT.getSizeInBits()) {
3460 // We can turn this into an SRA iff the input to the SRL is already sign
3462 unsigned InSignBits = DAG.ComputeNumSignBits(N0.getOperand(0));
3463 if (VT.getSizeInBits()-(ShAmt->getZExtValue()+EVTBits) < InSignBits)
3464 return DAG.getNode(ISD::SRA, VT, N0.getOperand(0), N0.getOperand(1));
3468 // fold (sext_inreg (extload x)) -> (sextload x)
3469 if (ISD::isEXTLoad(N0.getNode()) &&
3470 ISD::isUNINDEXEDLoad(N0.getNode()) &&
3471 EVT == cast<LoadSDNode>(N0)->getMemoryVT() &&
3472 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
3473 TLI.isLoadExtLegal(ISD::SEXTLOAD, EVT))) {
3474 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
3475 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, LN0->getChain(),
3476 LN0->getBasePtr(), LN0->getSrcValue(),
3477 LN0->getSrcValueOffset(), EVT,
3478 LN0->isVolatile(), LN0->getAlignment());
3479 CombineTo(N, ExtLoad);
3480 CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1));
3481 return SDValue(N, 0); // Return N so it doesn't get rechecked!
3483 // fold (sext_inreg (zextload x)) -> (sextload x) iff load has one use
3484 if (ISD::isZEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) &&
3486 EVT == cast<LoadSDNode>(N0)->getMemoryVT() &&
3487 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
3488 TLI.isLoadExtLegal(ISD::SEXTLOAD, EVT))) {
3489 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
3490 SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, LN0->getChain(),
3491 LN0->getBasePtr(), LN0->getSrcValue(),
3492 LN0->getSrcValueOffset(), EVT,
3493 LN0->isVolatile(), LN0->getAlignment());
3494 CombineTo(N, ExtLoad);
3495 CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1));
3496 return SDValue(N, 0); // Return N so it doesn't get rechecked!
3501 SDValue DAGCombiner::visitTRUNCATE(SDNode *N) {
3502 SDValue N0 = N->getOperand(0);
3503 MVT VT = N->getValueType(0);
3506 if (N0.getValueType() == N->getValueType(0))
3508 // fold (truncate c1) -> c1
3509 if (isa<ConstantSDNode>(N0))
3510 return DAG.getNode(ISD::TRUNCATE, VT, N0);
3511 // fold (truncate (truncate x)) -> (truncate x)
3512 if (N0.getOpcode() == ISD::TRUNCATE)
3513 return DAG.getNode(ISD::TRUNCATE, VT, N0.getOperand(0));
3514 // fold (truncate (ext x)) -> (ext x) or (truncate x) or x
3515 if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::SIGN_EXTEND||
3516 N0.getOpcode() == ISD::ANY_EXTEND) {
3517 if (N0.getOperand(0).getValueType().bitsLT(VT))
3518 // if the source is smaller than the dest, we still need an extend
3519 return DAG.getNode(N0.getOpcode(), VT, N0.getOperand(0));
3520 else if (N0.getOperand(0).getValueType().bitsGT(VT))
3521 // if the source is larger than the dest, than we just need the truncate
3522 return DAG.getNode(ISD::TRUNCATE, VT, N0.getOperand(0));
3524 // if the source and dest are the same type, we can drop both the extend
3526 return N0.getOperand(0);
3529 // See if we can simplify the input to this truncate through knowledge that
3530 // only the low bits are being used. For example "trunc (or (shl x, 8), y)"
3533 GetDemandedBits(N0, APInt::getLowBitsSet(N0.getValueSizeInBits(),
3534 VT.getSizeInBits()));
3535 if (Shorter.getNode())
3536 return DAG.getNode(ISD::TRUNCATE, VT, Shorter);
3538 // fold (truncate (load x)) -> (smaller load x)
3539 // fold (truncate (srl (load x), c)) -> (smaller load (x+c/evtbits))
3540 return ReduceLoadWidth(N);
3543 static SDNode *getBuildPairElt(SDNode *N, unsigned i) {
3544 SDValue Elt = N->getOperand(i);
3545 if (Elt.getOpcode() != ISD::MERGE_VALUES)
3546 return Elt.getNode();
3547 return Elt.getOperand(Elt.getResNo()).getNode();
3550 /// CombineConsecutiveLoads - build_pair (load, load) -> load
3551 /// if load locations are consecutive.
3552 SDValue DAGCombiner::CombineConsecutiveLoads(SDNode *N, MVT VT) {
3553 assert(N->getOpcode() == ISD::BUILD_PAIR);
3555 SDNode *LD1 = getBuildPairElt(N, 0);
3556 if (!ISD::isNON_EXTLoad(LD1) || !LD1->hasOneUse())
3558 MVT LD1VT = LD1->getValueType(0);
3559 SDNode *LD2 = getBuildPairElt(N, 1);
3560 const MachineFrameInfo *MFI = DAG.getMachineFunction().getFrameInfo();
3561 if (ISD::isNON_EXTLoad(LD2) &&
3563 // If both are volatile this would reduce the number of volatile loads.
3564 // If one is volatile it might be ok, but play conservative and bail out.
3565 !cast<LoadSDNode>(LD1)->isVolatile() &&
3566 !cast<LoadSDNode>(LD2)->isVolatile() &&
3567 TLI.isConsecutiveLoad(LD2, LD1, LD1VT.getSizeInBits()/8, 1, MFI)) {
3568 LoadSDNode *LD = cast<LoadSDNode>(LD1);
3569 unsigned Align = LD->getAlignment();
3570 unsigned NewAlign = TLI.getTargetData()->
3571 getABITypeAlignment(VT.getTypeForMVT());
3572 if (NewAlign <= Align &&
3573 (!LegalOperations || TLI.isOperationLegal(ISD::LOAD, VT)))
3574 return DAG.getLoad(VT, LD->getChain(), LD->getBasePtr(),
3575 LD->getSrcValue(), LD->getSrcValueOffset(),
3581 SDValue DAGCombiner::visitBIT_CONVERT(SDNode *N) {
3582 SDValue N0 = N->getOperand(0);
3583 MVT VT = N->getValueType(0);
3585 // If the input is a BUILD_VECTOR with all constant elements, fold this now.
3586 // Only do this before legalize, since afterward the target may be depending
3587 // on the bitconvert.
3588 // First check to see if this is all constant.
3590 N0.getOpcode() == ISD::BUILD_VECTOR && N0.getNode()->hasOneUse() &&
3592 bool isSimple = true;
3593 for (unsigned i = 0, e = N0.getNumOperands(); i != e; ++i)
3594 if (N0.getOperand(i).getOpcode() != ISD::UNDEF &&
3595 N0.getOperand(i).getOpcode() != ISD::Constant &&
3596 N0.getOperand(i).getOpcode() != ISD::ConstantFP) {
3601 MVT DestEltVT = N->getValueType(0).getVectorElementType();
3602 assert(!DestEltVT.isVector() &&
3603 "Element type of vector ValueType must not be vector!");
3605 return ConstantFoldBIT_CONVERTofBUILD_VECTOR(N0.getNode(), DestEltVT);
3609 // If the input is a constant, let getNode fold it.
3610 if (isa<ConstantSDNode>(N0) || isa<ConstantFPSDNode>(N0)) {
3611 SDValue Res = DAG.getNode(ISD::BIT_CONVERT, VT, N0);
3612 if (Res.getNode() != N) return Res;
3615 if (N0.getOpcode() == ISD::BIT_CONVERT) // conv(conv(x,t1),t2) -> conv(x,t2)
3616 return DAG.getNode(ISD::BIT_CONVERT, VT, N0.getOperand(0));
3618 // fold (conv (load x)) -> (load (conv*)x)
3619 // If the resultant load doesn't need a higher alignment than the original!
3620 if (ISD::isNormalLoad(N0.getNode()) && N0.hasOneUse() &&
3621 // Do not change the width of a volatile load.
3622 !cast<LoadSDNode>(N0)->isVolatile() &&
3623 (!LegalOperations || TLI.isOperationLegal(ISD::LOAD, VT))) {
3624 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
3625 unsigned Align = TLI.getTargetData()->
3626 getABITypeAlignment(VT.getTypeForMVT());
3627 unsigned OrigAlign = LN0->getAlignment();
3628 if (Align <= OrigAlign) {
3629 SDValue Load = DAG.getLoad(VT, LN0->getChain(), LN0->getBasePtr(),
3630 LN0->getSrcValue(), LN0->getSrcValueOffset(),
3631 LN0->isVolatile(), OrigAlign);
3633 CombineTo(N0.getNode(),
3634 DAG.getNode(ISD::BIT_CONVERT, N0.getValueType(), Load),
3640 // Fold bitconvert(fneg(x)) -> xor(bitconvert(x), signbit)
3641 // Fold bitconvert(fabs(x)) -> and(bitconvert(x), ~signbit)
3642 // This often reduces constant pool loads.
3643 if ((N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FABS) &&
3644 N0.getNode()->hasOneUse() && VT.isInteger() && !VT.isVector()) {
3645 SDValue NewConv = DAG.getNode(ISD::BIT_CONVERT, VT, N0.getOperand(0));
3646 AddToWorkList(NewConv.getNode());
3648 APInt SignBit = APInt::getSignBit(VT.getSizeInBits());
3649 if (N0.getOpcode() == ISD::FNEG)
3650 return DAG.getNode(ISD::XOR, VT, NewConv, DAG.getConstant(SignBit, VT));
3651 assert(N0.getOpcode() == ISD::FABS);
3652 return DAG.getNode(ISD::AND, VT, NewConv, DAG.getConstant(~SignBit, VT));
3655 // Fold bitconvert(fcopysign(cst, x)) -> bitconvert(x)&sign | cst&~sign'
3656 // Note that we don't handle copysign(x,cst) because this can always be folded
3657 // to an fneg or fabs.
3658 if (N0.getOpcode() == ISD::FCOPYSIGN && N0.getNode()->hasOneUse() &&
3659 isa<ConstantFPSDNode>(N0.getOperand(0)) &&
3660 VT.isInteger() && !VT.isVector()) {
3661 unsigned OrigXWidth = N0.getOperand(1).getValueType().getSizeInBits();
3662 MVT IntXVT = MVT::getIntegerVT(OrigXWidth);
3663 if (TLI.isTypeLegal(IntXVT) || !LegalTypes) {
3664 SDValue X = DAG.getNode(ISD::BIT_CONVERT, IntXVT, N0.getOperand(1));
3665 AddToWorkList(X.getNode());
3667 // If X has a different width than the result/lhs, sext it or truncate it.
3668 unsigned VTWidth = VT.getSizeInBits();
3669 if (OrigXWidth < VTWidth) {
3670 X = DAG.getNode(ISD::SIGN_EXTEND, VT, X);
3671 AddToWorkList(X.getNode());
3672 } else if (OrigXWidth > VTWidth) {
3673 // To get the sign bit in the right place, we have to shift it right
3674 // before truncating.
3675 X = DAG.getNode(ISD::SRL, X.getValueType(), X,
3676 DAG.getConstant(OrigXWidth-VTWidth, X.getValueType()));
3677 AddToWorkList(X.getNode());
3678 X = DAG.getNode(ISD::TRUNCATE, VT, X);
3679 AddToWorkList(X.getNode());
3682 APInt SignBit = APInt::getSignBit(VT.getSizeInBits());
3683 X = DAG.getNode(ISD::AND, VT, X, DAG.getConstant(SignBit, VT));
3684 AddToWorkList(X.getNode());
3686 SDValue Cst = DAG.getNode(ISD::BIT_CONVERT, VT, N0.getOperand(0));
3687 Cst = DAG.getNode(ISD::AND, VT, Cst, DAG.getConstant(~SignBit, VT));
3688 AddToWorkList(Cst.getNode());
3690 return DAG.getNode(ISD::OR, VT, X, Cst);
3694 // bitconvert(build_pair(ld, ld)) -> ld iff load locations are consecutive.
3695 if (N0.getOpcode() == ISD::BUILD_PAIR) {
3696 SDValue CombineLD = CombineConsecutiveLoads(N0.getNode(), VT);
3697 if (CombineLD.getNode())
3704 SDValue DAGCombiner::visitBUILD_PAIR(SDNode *N) {
3705 MVT VT = N->getValueType(0);
3706 return CombineConsecutiveLoads(N, VT);
3709 /// ConstantFoldBIT_CONVERTofBUILD_VECTOR - We know that BV is a build_vector
3710 /// node with Constant, ConstantFP or Undef operands. DstEltVT indicates the
3711 /// destination element value type.
3712 SDValue DAGCombiner::
3713 ConstantFoldBIT_CONVERTofBUILD_VECTOR(SDNode *BV, MVT DstEltVT) {
3714 MVT SrcEltVT = BV->getOperand(0).getValueType();
3716 // If this is already the right type, we're done.
3717 if (SrcEltVT == DstEltVT) return SDValue(BV, 0);
3719 unsigned SrcBitSize = SrcEltVT.getSizeInBits();
3720 unsigned DstBitSize = DstEltVT.getSizeInBits();
3722 // If this is a conversion of N elements of one type to N elements of another
3723 // type, convert each element. This handles FP<->INT cases.
3724 if (SrcBitSize == DstBitSize) {
3725 SmallVector<SDValue, 8> Ops;
3726 for (unsigned i = 0, e = BV->getNumOperands(); i != e; ++i) {
3727 Ops.push_back(DAG.getNode(ISD::BIT_CONVERT, DstEltVT, BV->getOperand(i)));
3728 AddToWorkList(Ops.back().getNode());
3730 MVT VT = MVT::getVectorVT(DstEltVT,
3731 BV->getValueType(0).getVectorNumElements());
3732 return DAG.getNode(ISD::BUILD_VECTOR, VT, &Ops[0], Ops.size());
3735 // Otherwise, we're growing or shrinking the elements. To avoid having to
3736 // handle annoying details of growing/shrinking FP values, we convert them to
3738 if (SrcEltVT.isFloatingPoint()) {
3739 // Convert the input float vector to a int vector where the elements are the
3741 assert((SrcEltVT == MVT::f32 || SrcEltVT == MVT::f64) && "Unknown FP VT!");
3742 MVT IntVT = MVT::getIntegerVT(SrcEltVT.getSizeInBits());
3743 BV = ConstantFoldBIT_CONVERTofBUILD_VECTOR(BV, IntVT).getNode();
3747 // Now we know the input is an integer vector. If the output is a FP type,
3748 // convert to integer first, then to FP of the right size.
3749 if (DstEltVT.isFloatingPoint()) {
3750 assert((DstEltVT == MVT::f32 || DstEltVT == MVT::f64) && "Unknown FP VT!");
3751 MVT TmpVT = MVT::getIntegerVT(DstEltVT.getSizeInBits());
3752 SDNode *Tmp = ConstantFoldBIT_CONVERTofBUILD_VECTOR(BV, TmpVT).getNode();
3754 // Next, convert to FP elements of the same size.
3755 return ConstantFoldBIT_CONVERTofBUILD_VECTOR(Tmp, DstEltVT);
3758 // Okay, we know the src/dst types are both integers of differing types.
3759 // Handling growing first.
3760 assert(SrcEltVT.isInteger() && DstEltVT.isInteger());
3761 if (SrcBitSize < DstBitSize) {
3762 unsigned NumInputsPerOutput = DstBitSize/SrcBitSize;
3764 SmallVector<SDValue, 8> Ops;
3765 for (unsigned i = 0, e = BV->getNumOperands(); i != e;
3766 i += NumInputsPerOutput) {
3767 bool isLE = TLI.isLittleEndian();
3768 APInt NewBits = APInt(DstBitSize, 0);
3769 bool EltIsUndef = true;
3770 for (unsigned j = 0; j != NumInputsPerOutput; ++j) {
3771 // Shift the previously computed bits over.
3772 NewBits <<= SrcBitSize;
3773 SDValue Op = BV->getOperand(i+ (isLE ? (NumInputsPerOutput-j-1) : j));
3774 if (Op.getOpcode() == ISD::UNDEF) continue;
3778 APInt(cast<ConstantSDNode>(Op)->getAPIntValue()).zext(DstBitSize);
3782 Ops.push_back(DAG.getNode(ISD::UNDEF, DstEltVT));
3784 Ops.push_back(DAG.getConstant(NewBits, DstEltVT));
3787 MVT VT = MVT::getVectorVT(DstEltVT, Ops.size());
3788 return DAG.getNode(ISD::BUILD_VECTOR, VT, &Ops[0], Ops.size());
3791 // Finally, this must be the case where we are shrinking elements: each input
3792 // turns into multiple outputs.
3793 bool isS2V = ISD::isScalarToVector(BV);
3794 unsigned NumOutputsPerInput = SrcBitSize/DstBitSize;
3795 MVT VT = MVT::getVectorVT(DstEltVT, NumOutputsPerInput*BV->getNumOperands());
3796 SmallVector<SDValue, 8> Ops;
3797 for (unsigned i = 0, e = BV->getNumOperands(); i != e; ++i) {
3798 if (BV->getOperand(i).getOpcode() == ISD::UNDEF) {
3799 for (unsigned j = 0; j != NumOutputsPerInput; ++j)
3800 Ops.push_back(DAG.getNode(ISD::UNDEF, DstEltVT));
3803 APInt OpVal = cast<ConstantSDNode>(BV->getOperand(i))->getAPIntValue();
3804 for (unsigned j = 0; j != NumOutputsPerInput; ++j) {
3805 APInt ThisVal = APInt(OpVal).trunc(DstBitSize);
3806 Ops.push_back(DAG.getConstant(ThisVal, DstEltVT));
3807 if (isS2V && i == 0 && j == 0 && APInt(ThisVal).zext(SrcBitSize) == OpVal)
3808 // Simply turn this into a SCALAR_TO_VECTOR of the new type.
3809 return DAG.getNode(ISD::SCALAR_TO_VECTOR, VT, Ops[0]);
3810 OpVal = OpVal.lshr(DstBitSize);
3813 // For big endian targets, swap the order of the pieces of each element.
3814 if (TLI.isBigEndian())
3815 std::reverse(Ops.end()-NumOutputsPerInput, Ops.end());
3817 return DAG.getNode(ISD::BUILD_VECTOR, VT, &Ops[0], Ops.size());
3822 SDValue DAGCombiner::visitFADD(SDNode *N) {
3823 SDValue N0 = N->getOperand(0);
3824 SDValue N1 = N->getOperand(1);
3825 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
3826 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
3827 MVT VT = N->getValueType(0);
3830 if (VT.isVector()) {
3831 SDValue FoldedVOp = SimplifyVBinOp(N);
3832 if (FoldedVOp.getNode()) return FoldedVOp;
3835 // fold (fadd c1, c2) -> c1+c2
3836 if (N0CFP && N1CFP && VT != MVT::ppcf128)
3837 return DAG.getNode(ISD::FADD, VT, N0, N1);
3838 // canonicalize constant to RHS
3839 if (N0CFP && !N1CFP)
3840 return DAG.getNode(ISD::FADD, VT, N1, N0);
3841 // fold (A + 0) -> A
3842 if (UnsafeFPMath && N1CFP && N1CFP->getValueAPF().isZero())
3844 // fold (A + (-B)) -> A-B
3845 if (isNegatibleForFree(N1, LegalOperations) == 2)
3846 return DAG.getNode(ISD::FSUB, VT, N0,
3847 GetNegatedExpression(N1, DAG, LegalOperations));
3848 // fold ((-A) + B) -> B-A
3849 if (isNegatibleForFree(N0, LegalOperations) == 2)
3850 return DAG.getNode(ISD::FSUB, VT, N1,
3851 GetNegatedExpression(N0, DAG, LegalOperations));
3853 // If allowed, fold (fadd (fadd x, c1), c2) -> (fadd x, (fadd c1, c2))
3854 if (UnsafeFPMath && N1CFP && N0.getOpcode() == ISD::FADD &&
3855 N0.getNode()->hasOneUse() && isa<ConstantFPSDNode>(N0.getOperand(1)))
3856 return DAG.getNode(ISD::FADD, VT, N0.getOperand(0),
3857 DAG.getNode(ISD::FADD, VT, N0.getOperand(1), N1));
3862 SDValue DAGCombiner::visitFSUB(SDNode *N) {
3863 SDValue N0 = N->getOperand(0);
3864 SDValue N1 = N->getOperand(1);
3865 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
3866 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
3867 MVT VT = N->getValueType(0);
3870 if (VT.isVector()) {
3871 SDValue FoldedVOp = SimplifyVBinOp(N);
3872 if (FoldedVOp.getNode()) return FoldedVOp;
3875 // fold (fsub c1, c2) -> c1-c2
3876 if (N0CFP && N1CFP && VT != MVT::ppcf128)
3877 return DAG.getNode(ISD::FSUB, VT, N0, N1);
3879 if (UnsafeFPMath && N1CFP && N1CFP->getValueAPF().isZero())
3882 if (UnsafeFPMath && N0CFP && N0CFP->getValueAPF().isZero()) {
3883 if (isNegatibleForFree(N1, LegalOperations))
3884 return GetNegatedExpression(N1, DAG, LegalOperations);
3885 if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT))
3886 return DAG.getNode(ISD::FNEG, VT, N1);
3888 // fold (A-(-B)) -> A+B
3889 if (isNegatibleForFree(N1, LegalOperations))
3890 return DAG.getNode(ISD::FADD, VT, N0,
3891 GetNegatedExpression(N1, DAG, LegalOperations));
3896 SDValue DAGCombiner::visitFMUL(SDNode *N) {
3897 SDValue N0 = N->getOperand(0);
3898 SDValue N1 = N->getOperand(1);
3899 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
3900 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
3901 MVT VT = N->getValueType(0);
3904 if (VT.isVector()) {
3905 SDValue FoldedVOp = SimplifyVBinOp(N);
3906 if (FoldedVOp.getNode()) return FoldedVOp;
3909 // fold (fmul c1, c2) -> c1*c2
3910 if (N0CFP && N1CFP && VT != MVT::ppcf128)
3911 return DAG.getNode(ISD::FMUL, VT, N0, N1);
3912 // canonicalize constant to RHS
3913 if (N0CFP && !N1CFP)
3914 return DAG.getNode(ISD::FMUL, VT, N1, N0);
3915 // fold (A * 0) -> 0
3916 if (UnsafeFPMath && N1CFP && N1CFP->getValueAPF().isZero())
3918 // fold (fmul X, 2.0) -> (fadd X, X)
3919 if (N1CFP && N1CFP->isExactlyValue(+2.0))
3920 return DAG.getNode(ISD::FADD, VT, N0, N0);
3921 // fold (fmul X, -1.0) -> (fneg X)
3922 if (N1CFP && N1CFP->isExactlyValue(-1.0))
3923 if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT))
3924 return DAG.getNode(ISD::FNEG, VT, N0);
3927 if (char LHSNeg = isNegatibleForFree(N0, LegalOperations)) {
3928 if (char RHSNeg = isNegatibleForFree(N1, LegalOperations)) {
3929 // Both can be negated for free, check to see if at least one is cheaper
3931 if (LHSNeg == 2 || RHSNeg == 2)
3932 return DAG.getNode(ISD::FMUL, VT,
3933 GetNegatedExpression(N0, DAG, LegalOperations),
3934 GetNegatedExpression(N1, DAG, LegalOperations));
3938 // If allowed, fold (fmul (fmul x, c1), c2) -> (fmul x, (fmul c1, c2))
3939 if (UnsafeFPMath && N1CFP && N0.getOpcode() == ISD::FMUL &&
3940 N0.getNode()->hasOneUse() && isa<ConstantFPSDNode>(N0.getOperand(1)))
3941 return DAG.getNode(ISD::FMUL, VT, N0.getOperand(0),
3942 DAG.getNode(ISD::FMUL, VT, N0.getOperand(1), N1));
3947 SDValue DAGCombiner::visitFDIV(SDNode *N) {
3948 SDValue N0 = N->getOperand(0);
3949 SDValue N1 = N->getOperand(1);
3950 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
3951 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
3952 MVT VT = N->getValueType(0);
3955 if (VT.isVector()) {
3956 SDValue FoldedVOp = SimplifyVBinOp(N);
3957 if (FoldedVOp.getNode()) return FoldedVOp;
3960 // fold (fdiv c1, c2) -> c1/c2
3961 if (N0CFP && N1CFP && VT != MVT::ppcf128)
3962 return DAG.getNode(ISD::FDIV, VT, N0, N1);
3966 if (char LHSNeg = isNegatibleForFree(N0, LegalOperations)) {
3967 if (char RHSNeg = isNegatibleForFree(N1, LegalOperations)) {
3968 // Both can be negated for free, check to see if at least one is cheaper
3970 if (LHSNeg == 2 || RHSNeg == 2)
3971 return DAG.getNode(ISD::FDIV, VT,
3972 GetNegatedExpression(N0, DAG, LegalOperations),
3973 GetNegatedExpression(N1, DAG, LegalOperations));
3980 SDValue DAGCombiner::visitFREM(SDNode *N) {
3981 SDValue N0 = N->getOperand(0);
3982 SDValue N1 = N->getOperand(1);
3983 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
3984 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
3985 MVT VT = N->getValueType(0);
3987 // fold (frem c1, c2) -> fmod(c1,c2)
3988 if (N0CFP && N1CFP && VT != MVT::ppcf128)
3989 return DAG.getNode(ISD::FREM, VT, N0, N1);
3994 SDValue DAGCombiner::visitFCOPYSIGN(SDNode *N) {
3995 SDValue N0 = N->getOperand(0);
3996 SDValue N1 = N->getOperand(1);
3997 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
3998 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
3999 MVT VT = N->getValueType(0);
4001 if (N0CFP && N1CFP && VT != MVT::ppcf128) // Constant fold
4002 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1);
4005 const APFloat& V = N1CFP->getValueAPF();
4006 // copysign(x, c1) -> fabs(x) iff ispos(c1)
4007 // copysign(x, c1) -> fneg(fabs(x)) iff isneg(c1)
4008 if (!V.isNegative()) {
4009 if (!LegalOperations || TLI.isOperationLegal(ISD::FABS, VT))
4010 return DAG.getNode(ISD::FABS, VT, N0);
4012 if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT))
4013 return DAG.getNode(ISD::FNEG, VT, DAG.getNode(ISD::FABS, VT, N0));
4017 // copysign(fabs(x), y) -> copysign(x, y)
4018 // copysign(fneg(x), y) -> copysign(x, y)
4019 // copysign(copysign(x,z), y) -> copysign(x, y)
4020 if (N0.getOpcode() == ISD::FABS || N0.getOpcode() == ISD::FNEG ||
4021 N0.getOpcode() == ISD::FCOPYSIGN)
4022 return DAG.getNode(ISD::FCOPYSIGN, VT, N0.getOperand(0), N1);
4024 // copysign(x, abs(y)) -> abs(x)
4025 if (N1.getOpcode() == ISD::FABS)
4026 return DAG.getNode(ISD::FABS, VT, N0);
4028 // copysign(x, copysign(y,z)) -> copysign(x, z)
4029 if (N1.getOpcode() == ISD::FCOPYSIGN)
4030 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1.getOperand(1));
4032 // copysign(x, fp_extend(y)) -> copysign(x, y)
4033 // copysign(x, fp_round(y)) -> copysign(x, y)
4034 if (N1.getOpcode() == ISD::FP_EXTEND || N1.getOpcode() == ISD::FP_ROUND)
4035 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1.getOperand(0));
4042 SDValue DAGCombiner::visitSINT_TO_FP(SDNode *N) {
4043 SDValue N0 = N->getOperand(0);
4044 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
4045 MVT VT = N->getValueType(0);
4046 MVT OpVT = N0.getValueType();
4048 // fold (sint_to_fp c1) -> c1fp
4049 if (N0C && OpVT != MVT::ppcf128)
4050 return DAG.getNode(ISD::SINT_TO_FP, VT, N0);
4052 // If the input is a legal type, and SINT_TO_FP is not legal on this target,
4053 // but UINT_TO_FP is legal on this target, try to convert.
4054 if (!TLI.isOperationLegalOrCustom(ISD::SINT_TO_FP, OpVT) &&
4055 TLI.isOperationLegalOrCustom(ISD::UINT_TO_FP, OpVT)) {
4056 // If the sign bit is known to be zero, we can change this to UINT_TO_FP.
4057 if (DAG.SignBitIsZero(N0))
4058 return DAG.getNode(ISD::UINT_TO_FP, VT, N0);
4065 SDValue DAGCombiner::visitUINT_TO_FP(SDNode *N) {
4066 SDValue N0 = N->getOperand(0);
4067 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
4068 MVT VT = N->getValueType(0);
4069 MVT OpVT = N0.getValueType();
4071 // fold (uint_to_fp c1) -> c1fp
4072 if (N0C && OpVT != MVT::ppcf128)
4073 return DAG.getNode(ISD::UINT_TO_FP, VT, N0);
4075 // If the input is a legal type, and UINT_TO_FP is not legal on this target,
4076 // but SINT_TO_FP is legal on this target, try to convert.
4077 if (!TLI.isOperationLegalOrCustom(ISD::UINT_TO_FP, OpVT) &&
4078 TLI.isOperationLegalOrCustom(ISD::SINT_TO_FP, OpVT)) {
4079 // If the sign bit is known to be zero, we can change this to SINT_TO_FP.
4080 if (DAG.SignBitIsZero(N0))
4081 return DAG.getNode(ISD::SINT_TO_FP, VT, N0);
4087 SDValue DAGCombiner::visitFP_TO_SINT(SDNode *N) {
4088 SDValue N0 = N->getOperand(0);
4089 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
4090 MVT VT = N->getValueType(0);
4092 // fold (fp_to_sint c1fp) -> c1
4094 return DAG.getNode(ISD::FP_TO_SINT, VT, N0);
4098 SDValue DAGCombiner::visitFP_TO_UINT(SDNode *N) {
4099 SDValue N0 = N->getOperand(0);
4100 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
4101 MVT VT = N->getValueType(0);
4103 // fold (fp_to_uint c1fp) -> c1
4104 if (N0CFP && VT != MVT::ppcf128)
4105 return DAG.getNode(ISD::FP_TO_UINT, VT, N0);
4109 SDValue DAGCombiner::visitFP_ROUND(SDNode *N) {
4110 SDValue N0 = N->getOperand(0);
4111 SDValue N1 = N->getOperand(1);
4112 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
4113 MVT VT = N->getValueType(0);
4115 // fold (fp_round c1fp) -> c1fp
4116 if (N0CFP && N0.getValueType() != MVT::ppcf128)
4117 return DAG.getNode(ISD::FP_ROUND, VT, N0, N1);
4119 // fold (fp_round (fp_extend x)) -> x
4120 if (N0.getOpcode() == ISD::FP_EXTEND && VT == N0.getOperand(0).getValueType())
4121 return N0.getOperand(0);
4123 // fold (fp_round (fp_round x)) -> (fp_round x)
4124 if (N0.getOpcode() == ISD::FP_ROUND) {
4125 // This is a value preserving truncation if both round's are.
4126 bool IsTrunc = N->getConstantOperandVal(1) == 1 &&
4127 N0.getNode()->getConstantOperandVal(1) == 1;
4128 return DAG.getNode(ISD::FP_ROUND, VT, N0.getOperand(0),
4129 DAG.getIntPtrConstant(IsTrunc));
4132 // fold (fp_round (copysign X, Y)) -> (copysign (fp_round X), Y)
4133 if (N0.getOpcode() == ISD::FCOPYSIGN && N0.getNode()->hasOneUse()) {
4134 SDValue Tmp = DAG.getNode(ISD::FP_ROUND, VT, N0.getOperand(0), N1);
4135 AddToWorkList(Tmp.getNode());
4136 return DAG.getNode(ISD::FCOPYSIGN, VT, Tmp, N0.getOperand(1));
4142 SDValue DAGCombiner::visitFP_ROUND_INREG(SDNode *N) {
4143 SDValue N0 = N->getOperand(0);
4144 MVT VT = N->getValueType(0);
4145 MVT EVT = cast<VTSDNode>(N->getOperand(1))->getVT();
4146 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
4148 // fold (fp_round_inreg c1fp) -> c1fp
4149 if (N0CFP && (TLI.isTypeLegal(EVT) || !LegalTypes)) {
4150 SDValue Round = DAG.getConstantFP(*N0CFP->getConstantFPValue(), EVT);
4151 return DAG.getNode(ISD::FP_EXTEND, VT, Round);
4156 SDValue DAGCombiner::visitFP_EXTEND(SDNode *N) {
4157 SDValue N0 = N->getOperand(0);
4158 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
4159 MVT VT = N->getValueType(0);
4161 // If this is fp_round(fpextend), don't fold it, allow ourselves to be folded.
4162 if (N->hasOneUse() &&
4163 N->use_begin()->getOpcode() == ISD::FP_ROUND)
4166 // fold (fp_extend c1fp) -> c1fp
4167 if (N0CFP && VT != MVT::ppcf128)
4168 return DAG.getNode(ISD::FP_EXTEND, VT, N0);
4170 // Turn fp_extend(fp_round(X, 1)) -> x since the fp_round doesn't affect the
4172 if (N0.getOpcode() == ISD::FP_ROUND
4173 && N0.getNode()->getConstantOperandVal(1) == 1) {
4174 SDValue In = N0.getOperand(0);
4175 if (In.getValueType() == VT) return In;
4176 if (VT.bitsLT(In.getValueType()))
4177 return DAG.getNode(ISD::FP_ROUND, VT, In, N0.getOperand(1));
4178 return DAG.getNode(ISD::FP_EXTEND, VT, In);
4181 // fold (fpext (load x)) -> (fpext (fptrunc (extload x)))
4182 if (ISD::isNON_EXTLoad(N0.getNode()) && N0.hasOneUse() &&
4183 ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
4184 TLI.isLoadExtLegal(ISD::EXTLOAD, N0.getValueType()))) {
4185 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
4186 SDValue ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, VT, LN0->getChain(),
4187 LN0->getBasePtr(), LN0->getSrcValue(),
4188 LN0->getSrcValueOffset(),
4190 LN0->isVolatile(), LN0->getAlignment());
4191 CombineTo(N, ExtLoad);
4192 CombineTo(N0.getNode(), DAG.getNode(ISD::FP_ROUND, N0.getValueType(),
4193 ExtLoad, DAG.getIntPtrConstant(1)),
4194 ExtLoad.getValue(1));
4195 return SDValue(N, 0); // Return N so it doesn't get rechecked!
4201 SDValue DAGCombiner::visitFNEG(SDNode *N) {
4202 SDValue N0 = N->getOperand(0);
4204 if (isNegatibleForFree(N0, LegalOperations))
4205 return GetNegatedExpression(N0, DAG, LegalOperations);
4207 // Transform fneg(bitconvert(x)) -> bitconvert(x^sign) to avoid loading
4208 // constant pool values.
4209 if (N0.getOpcode() == ISD::BIT_CONVERT && N0.getNode()->hasOneUse() &&
4210 N0.getOperand(0).getValueType().isInteger() &&
4211 !N0.getOperand(0).getValueType().isVector()) {
4212 SDValue Int = N0.getOperand(0);
4213 MVT IntVT = Int.getValueType();
4214 if (IntVT.isInteger() && !IntVT.isVector()) {
4215 Int = DAG.getNode(ISD::XOR, IntVT, Int,
4216 DAG.getConstant(IntVT.getIntegerVTSignBit(), IntVT));
4217 AddToWorkList(Int.getNode());
4218 return DAG.getNode(ISD::BIT_CONVERT, N->getValueType(0), Int);
4225 SDValue DAGCombiner::visitFABS(SDNode *N) {
4226 SDValue N0 = N->getOperand(0);
4227 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
4228 MVT VT = N->getValueType(0);
4230 // fold (fabs c1) -> fabs(c1)
4231 if (N0CFP && VT != MVT::ppcf128)
4232 return DAG.getNode(ISD::FABS, VT, N0);
4233 // fold (fabs (fabs x)) -> (fabs x)
4234 if (N0.getOpcode() == ISD::FABS)
4235 return N->getOperand(0);
4236 // fold (fabs (fneg x)) -> (fabs x)
4237 // fold (fabs (fcopysign x, y)) -> (fabs x)
4238 if (N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FCOPYSIGN)
4239 return DAG.getNode(ISD::FABS, VT, N0.getOperand(0));
4241 // Transform fabs(bitconvert(x)) -> bitconvert(x&~sign) to avoid loading
4242 // constant pool values.
4243 if (N0.getOpcode() == ISD::BIT_CONVERT && N0.getNode()->hasOneUse() &&
4244 N0.getOperand(0).getValueType().isInteger() &&
4245 !N0.getOperand(0).getValueType().isVector()) {
4246 SDValue Int = N0.getOperand(0);
4247 MVT IntVT = Int.getValueType();
4248 if (IntVT.isInteger() && !IntVT.isVector()) {
4249 Int = DAG.getNode(ISD::AND, IntVT, Int,
4250 DAG.getConstant(~IntVT.getIntegerVTSignBit(), IntVT));
4251 AddToWorkList(Int.getNode());
4252 return DAG.getNode(ISD::BIT_CONVERT, N->getValueType(0), Int);
4259 SDValue DAGCombiner::visitBRCOND(SDNode *N) {
4260 SDValue Chain = N->getOperand(0);
4261 SDValue N1 = N->getOperand(1);
4262 SDValue N2 = N->getOperand(2);
4263 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
4265 // never taken branch, fold to chain
4266 if (N1C && N1C->isNullValue())
4268 // unconditional branch
4269 if (N1C && N1C->getAPIntValue() == 1)
4270 return DAG.getNode(ISD::BR, MVT::Other, Chain, N2);
4271 // fold a brcond with a setcc condition into a BR_CC node if BR_CC is legal
4273 if (N1.getOpcode() == ISD::SETCC &&
4274 TLI.isOperationLegalOrCustom(ISD::BR_CC, MVT::Other)) {
4275 return DAG.getNode(ISD::BR_CC, MVT::Other, Chain, N1.getOperand(2),
4276 N1.getOperand(0), N1.getOperand(1), N2);
4281 // Operand List for BR_CC: Chain, CondCC, CondLHS, CondRHS, DestBB.
4283 SDValue DAGCombiner::visitBR_CC(SDNode *N) {
4284 CondCodeSDNode *CC = cast<CondCodeSDNode>(N->getOperand(1));
4285 SDValue CondLHS = N->getOperand(2), CondRHS = N->getOperand(3);
4287 // Use SimplifySetCC to simplify SETCC's.
4288 SDValue Simp = SimplifySetCC(TLI.getSetCCResultType(CondLHS.getValueType()),
4289 CondLHS, CondRHS, CC->get(), false);
4290 if (Simp.getNode()) AddToWorkList(Simp.getNode());
4292 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(Simp.getNode());
4294 // fold br_cc true, dest -> br dest (unconditional branch)
4295 if (SCCC && !SCCC->isNullValue())
4296 return DAG.getNode(ISD::BR, MVT::Other, N->getOperand(0),
4298 // fold br_cc false, dest -> unconditional fall through
4299 if (SCCC && SCCC->isNullValue())
4300 return N->getOperand(0);
4302 // fold to a simpler setcc
4303 if (Simp.getNode() && Simp.getOpcode() == ISD::SETCC)
4304 return DAG.getNode(ISD::BR_CC, MVT::Other, N->getOperand(0),
4305 Simp.getOperand(2), Simp.getOperand(0),
4306 Simp.getOperand(1), N->getOperand(4));
4311 /// CombineToPreIndexedLoadStore - Try turning a load / store into a
4312 /// pre-indexed load / store when the base pointer is an add or subtract
4313 /// and it has other uses besides the load / store. After the
4314 /// transformation, the new indexed load / store has effectively folded
4315 /// the add / subtract in and all of its other uses are redirected to the
4316 /// new load / store.
4317 bool DAGCombiner::CombineToPreIndexedLoadStore(SDNode *N) {
4318 if (!LegalOperations)
4324 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) {
4325 if (LD->isIndexed())
4327 VT = LD->getMemoryVT();
4328 if (!TLI.isIndexedLoadLegal(ISD::PRE_INC, VT) &&
4329 !TLI.isIndexedLoadLegal(ISD::PRE_DEC, VT))
4331 Ptr = LD->getBasePtr();
4332 } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) {
4333 if (ST->isIndexed())
4335 VT = ST->getMemoryVT();
4336 if (!TLI.isIndexedStoreLegal(ISD::PRE_INC, VT) &&
4337 !TLI.isIndexedStoreLegal(ISD::PRE_DEC, VT))
4339 Ptr = ST->getBasePtr();
4344 // If the pointer is not an add/sub, or if it doesn't have multiple uses, bail
4345 // out. There is no reason to make this a preinc/predec.
4346 if ((Ptr.getOpcode() != ISD::ADD && Ptr.getOpcode() != ISD::SUB) ||
4347 Ptr.getNode()->hasOneUse())
4350 // Ask the target to do addressing mode selection.
4353 ISD::MemIndexedMode AM = ISD::UNINDEXED;
4354 if (!TLI.getPreIndexedAddressParts(N, BasePtr, Offset, AM, DAG))
4356 // Don't create a indexed load / store with zero offset.
4357 if (isa<ConstantSDNode>(Offset) &&
4358 cast<ConstantSDNode>(Offset)->isNullValue())
4361 // Try turning it into a pre-indexed load / store except when:
4362 // 1) The new base ptr is a frame index.
4363 // 2) If N is a store and the new base ptr is either the same as or is a
4364 // predecessor of the value being stored.
4365 // 3) Another use of old base ptr is a predecessor of N. If ptr is folded
4366 // that would create a cycle.
4367 // 4) All uses are load / store ops that use it as old base ptr.
4369 // Check #1. Preinc'ing a frame index would require copying the stack pointer
4370 // (plus the implicit offset) to a register to preinc anyway.
4371 if (isa<FrameIndexSDNode>(BasePtr))
4376 SDValue Val = cast<StoreSDNode>(N)->getValue();
4377 if (Val == BasePtr || BasePtr.getNode()->isPredecessorOf(Val.getNode()))
4381 // Now check for #3 and #4.
4382 bool RealUse = false;
4383 for (SDNode::use_iterator I = Ptr.getNode()->use_begin(),
4384 E = Ptr.getNode()->use_end(); I != E; ++I) {
4388 if (Use->isPredecessorOf(N))
4391 if (!((Use->getOpcode() == ISD::LOAD &&
4392 cast<LoadSDNode>(Use)->getBasePtr() == Ptr) ||
4393 (Use->getOpcode() == ISD::STORE &&
4394 cast<StoreSDNode>(Use)->getBasePtr() == Ptr)))
4402 Result = DAG.getIndexedLoad(SDValue(N,0), BasePtr, Offset, AM);
4404 Result = DAG.getIndexedStore(SDValue(N,0), BasePtr, Offset, AM);
4407 DOUT << "\nReplacing.4 "; DEBUG(N->dump(&DAG));
4408 DOUT << "\nWith: "; DEBUG(Result.getNode()->dump(&DAG));
4410 WorkListRemover DeadNodes(*this);
4412 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(0),
4414 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Result.getValue(2),
4417 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(1),
4421 // Finally, since the node is now dead, remove it from the graph.
4424 // Replace the uses of Ptr with uses of the updated base value.
4425 DAG.ReplaceAllUsesOfValueWith(Ptr, Result.getValue(isLoad ? 1 : 0),
4427 removeFromWorkList(Ptr.getNode());
4428 DAG.DeleteNode(Ptr.getNode());
4433 /// CombineToPostIndexedLoadStore - Try to combine a load / store with a
4434 /// add / sub of the base pointer node into a post-indexed load / store.
4435 /// The transformation folded the add / subtract into the new indexed
4436 /// load / store effectively and all of its uses are redirected to the
4437 /// new load / store.
4438 bool DAGCombiner::CombineToPostIndexedLoadStore(SDNode *N) {
4439 if (!LegalOperations)
4445 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) {
4446 if (LD->isIndexed())
4448 VT = LD->getMemoryVT();
4449 if (!TLI.isIndexedLoadLegal(ISD::POST_INC, VT) &&
4450 !TLI.isIndexedLoadLegal(ISD::POST_DEC, VT))
4452 Ptr = LD->getBasePtr();
4453 } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) {
4454 if (ST->isIndexed())
4456 VT = ST->getMemoryVT();
4457 if (!TLI.isIndexedStoreLegal(ISD::POST_INC, VT) &&
4458 !TLI.isIndexedStoreLegal(ISD::POST_DEC, VT))
4460 Ptr = ST->getBasePtr();
4465 if (Ptr.getNode()->hasOneUse())
4468 for (SDNode::use_iterator I = Ptr.getNode()->use_begin(),
4469 E = Ptr.getNode()->use_end(); I != E; ++I) {
4472 (Op->getOpcode() != ISD::ADD && Op->getOpcode() != ISD::SUB))
4477 ISD::MemIndexedMode AM = ISD::UNINDEXED;
4478 if (TLI.getPostIndexedAddressParts(N, Op, BasePtr, Offset, AM, DAG)) {
4480 std::swap(BasePtr, Offset);
4483 // Don't create a indexed load / store with zero offset.
4484 if (isa<ConstantSDNode>(Offset) &&
4485 cast<ConstantSDNode>(Offset)->isNullValue())
4488 // Try turning it into a post-indexed load / store except when
4489 // 1) All uses are load / store ops that use it as base ptr.
4490 // 2) Op must be independent of N, i.e. Op is neither a predecessor
4491 // nor a successor of N. Otherwise, if Op is folded that would
4495 bool TryNext = false;
4496 for (SDNode::use_iterator II = BasePtr.getNode()->use_begin(),
4497 EE = BasePtr.getNode()->use_end(); II != EE; ++II) {
4499 if (Use == Ptr.getNode())
4502 // If all the uses are load / store addresses, then don't do the
4504 if (Use->getOpcode() == ISD::ADD || Use->getOpcode() == ISD::SUB){
4505 bool RealUse = false;
4506 for (SDNode::use_iterator III = Use->use_begin(),
4507 EEE = Use->use_end(); III != EEE; ++III) {
4508 SDNode *UseUse = *III;
4509 if (!((UseUse->getOpcode() == ISD::LOAD &&
4510 cast<LoadSDNode>(UseUse)->getBasePtr().getNode() == Use) ||
4511 (UseUse->getOpcode() == ISD::STORE &&
4512 cast<StoreSDNode>(UseUse)->getBasePtr().getNode() == Use)))
4526 if (!Op->isPredecessorOf(N) && !N->isPredecessorOf(Op)) {
4527 SDValue Result = isLoad
4528 ? DAG.getIndexedLoad(SDValue(N,0), BasePtr, Offset, AM)
4529 : DAG.getIndexedStore(SDValue(N,0), BasePtr, Offset, AM);
4532 DOUT << "\nReplacing.5 "; DEBUG(N->dump(&DAG));
4533 DOUT << "\nWith: "; DEBUG(Result.getNode()->dump(&DAG));
4535 WorkListRemover DeadNodes(*this);
4537 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(0),
4539 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Result.getValue(2),
4542 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(1),
4546 // Finally, since the node is now dead, remove it from the graph.
4549 // Replace the uses of Use with uses of the updated base value.
4550 DAG.ReplaceAllUsesOfValueWith(SDValue(Op, 0),
4551 Result.getValue(isLoad ? 1 : 0),
4553 removeFromWorkList(Op);
4562 /// InferAlignment - If we can infer some alignment information from this
4563 /// pointer, return it.
4564 static unsigned InferAlignment(SDValue Ptr, SelectionDAG &DAG) {
4565 // If this is a direct reference to a stack slot, use information about the
4566 // stack slot's alignment.
4567 int FrameIdx = 1 << 31;
4568 int64_t FrameOffset = 0;
4569 if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(Ptr)) {
4570 FrameIdx = FI->getIndex();
4571 } else if (Ptr.getOpcode() == ISD::ADD &&
4572 isa<ConstantSDNode>(Ptr.getOperand(1)) &&
4573 isa<FrameIndexSDNode>(Ptr.getOperand(0))) {
4574 FrameIdx = cast<FrameIndexSDNode>(Ptr.getOperand(0))->getIndex();
4575 FrameOffset = Ptr.getConstantOperandVal(1);
4578 if (FrameIdx != (1 << 31)) {
4579 // FIXME: Handle FI+CST.
4580 const MachineFrameInfo &MFI = *DAG.getMachineFunction().getFrameInfo();
4581 if (MFI.isFixedObjectIndex(FrameIdx)) {
4582 int64_t ObjectOffset = MFI.getObjectOffset(FrameIdx) + FrameOffset;
4584 // The alignment of the frame index can be determined from its offset from
4585 // the incoming frame position. If the frame object is at offset 32 and
4586 // the stack is guaranteed to be 16-byte aligned, then we know that the
4587 // object is 16-byte aligned.
4588 unsigned StackAlign = DAG.getTarget().getFrameInfo()->getStackAlignment();
4589 unsigned Align = MinAlign(ObjectOffset, StackAlign);
4591 // Finally, the frame object itself may have a known alignment. Factor
4592 // the alignment + offset into a new alignment. For example, if we know
4593 // the FI is 8 byte aligned, but the pointer is 4 off, we really have a
4594 // 4-byte alignment of the resultant pointer. Likewise align 4 + 4-byte
4595 // offset = 4-byte alignment, align 4 + 1-byte offset = align 1, etc.
4596 unsigned FIInfoAlign = MinAlign(MFI.getObjectAlignment(FrameIdx),
4598 return std::max(Align, FIInfoAlign);
4605 SDValue DAGCombiner::visitLOAD(SDNode *N) {
4606 LoadSDNode *LD = cast<LoadSDNode>(N);
4607 SDValue Chain = LD->getChain();
4608 SDValue Ptr = LD->getBasePtr();
4610 // Try to infer better alignment information than the load already has.
4611 if (!Fast && LD->isUnindexed()) {
4612 if (unsigned Align = InferAlignment(Ptr, DAG)) {
4613 if (Align > LD->getAlignment())
4614 return DAG.getExtLoad(LD->getExtensionType(), LD->getValueType(0),
4615 Chain, Ptr, LD->getSrcValue(),
4616 LD->getSrcValueOffset(), LD->getMemoryVT(),
4617 LD->isVolatile(), Align);
4622 // If load is not volatile and there are no uses of the loaded value (and
4623 // the updated indexed value in case of indexed loads), change uses of the
4624 // chain value into uses of the chain input (i.e. delete the dead load).
4625 if (!LD->isVolatile()) {
4626 if (N->getValueType(1) == MVT::Other) {
4628 if (N->hasNUsesOfValue(0, 0)) {
4629 // It's not safe to use the two value CombineTo variant here. e.g.
4630 // v1, chain2 = load chain1, loc
4631 // v2, chain3 = load chain2, loc
4633 // Now we replace use of chain2 with chain1. This makes the second load
4634 // isomorphic to the one we are deleting, and thus makes this load live.
4635 DOUT << "\nReplacing.6 "; DEBUG(N->dump(&DAG));
4636 DOUT << "\nWith chain: "; DEBUG(Chain.getNode()->dump(&DAG));
4638 WorkListRemover DeadNodes(*this);
4639 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Chain, &DeadNodes);
4640 if (N->use_empty()) {
4641 removeFromWorkList(N);
4644 return SDValue(N, 0); // Return N so it doesn't get rechecked!
4648 assert(N->getValueType(2) == MVT::Other && "Malformed indexed loads?");
4649 if (N->hasNUsesOfValue(0, 0) && N->hasNUsesOfValue(0, 1)) {
4650 SDValue Undef = DAG.getNode(ISD::UNDEF, N->getValueType(0));
4651 DOUT << "\nReplacing.6 "; DEBUG(N->dump(&DAG));
4652 DOUT << "\nWith: "; DEBUG(Undef.getNode()->dump(&DAG));
4653 DOUT << " and 2 other values\n";
4654 WorkListRemover DeadNodes(*this);
4655 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Undef, &DeadNodes);
4656 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1),
4657 DAG.getNode(ISD::UNDEF, N->getValueType(1)),
4659 DAG.ReplaceAllUsesOfValueWith(SDValue(N, 2), Chain, &DeadNodes);
4660 removeFromWorkList(N);
4662 return SDValue(N, 0); // Return N so it doesn't get rechecked!
4667 // If this load is directly stored, replace the load value with the stored
4669 // TODO: Handle store large -> read small portion.
4670 // TODO: Handle TRUNCSTORE/LOADEXT
4671 if (LD->getExtensionType() == ISD::NON_EXTLOAD &&
4672 !LD->isVolatile()) {
4673 if (ISD::isNON_TRUNCStore(Chain.getNode())) {
4674 StoreSDNode *PrevST = cast<StoreSDNode>(Chain);
4675 if (PrevST->getBasePtr() == Ptr &&
4676 PrevST->getValue().getValueType() == N->getValueType(0))
4677 return CombineTo(N, Chain.getOperand(1), Chain);
4682 // Walk up chain skipping non-aliasing memory nodes.
4683 SDValue BetterChain = FindBetterChain(N, Chain);
4685 // If there is a better chain.
4686 if (Chain != BetterChain) {
4689 // Replace the chain to void dependency.
4690 if (LD->getExtensionType() == ISD::NON_EXTLOAD) {
4691 ReplLoad = DAG.getLoad(N->getValueType(0), BetterChain, Ptr,
4692 LD->getSrcValue(), LD->getSrcValueOffset(),
4693 LD->isVolatile(), LD->getAlignment());
4695 ReplLoad = DAG.getExtLoad(LD->getExtensionType(),
4696 LD->getValueType(0),
4697 BetterChain, Ptr, LD->getSrcValue(),
4698 LD->getSrcValueOffset(),
4701 LD->getAlignment());
4704 // Create token factor to keep old chain connected.
4705 SDValue Token = DAG.getNode(ISD::TokenFactor, MVT::Other,
4706 Chain, ReplLoad.getValue(1));
4708 // Replace uses with load result and token factor. Don't add users
4710 return CombineTo(N, ReplLoad.getValue(0), Token, false);
4714 // Try transforming N to an indexed load.
4715 if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N))
4716 return SDValue(N, 0);
4722 SDValue DAGCombiner::visitSTORE(SDNode *N) {
4723 StoreSDNode *ST = cast<StoreSDNode>(N);
4724 SDValue Chain = ST->getChain();
4725 SDValue Value = ST->getValue();
4726 SDValue Ptr = ST->getBasePtr();
4728 // Try to infer better alignment information than the store already has.
4729 if (!Fast && ST->isUnindexed()) {
4730 if (unsigned Align = InferAlignment(Ptr, DAG)) {
4731 if (Align > ST->getAlignment())
4732 return DAG.getTruncStore(Chain, Value, Ptr, ST->getSrcValue(),
4733 ST->getSrcValueOffset(), ST->getMemoryVT(),
4734 ST->isVolatile(), Align);
4738 // If this is a store of a bit convert, store the input value if the
4739 // resultant store does not need a higher alignment than the original.
4740 if (Value.getOpcode() == ISD::BIT_CONVERT && !ST->isTruncatingStore() &&
4741 ST->isUnindexed()) {
4742 unsigned Align = ST->getAlignment();
4743 MVT SVT = Value.getOperand(0).getValueType();
4744 unsigned OrigAlign = TLI.getTargetData()->
4745 getABITypeAlignment(SVT.getTypeForMVT());
4746 if (Align <= OrigAlign &&
4747 ((!LegalOperations && !ST->isVolatile()) ||
4748 TLI.isOperationLegalOrCustom(ISD::STORE, SVT)))
4749 return DAG.getStore(Chain, Value.getOperand(0), Ptr, ST->getSrcValue(),
4750 ST->getSrcValueOffset(), ST->isVolatile(), OrigAlign);
4753 // Turn 'store float 1.0, Ptr' -> 'store int 0x12345678, Ptr'
4754 if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(Value)) {
4755 // NOTE: If the original store is volatile, this transform must not increase
4756 // the number of stores. For example, on x86-32 an f64 can be stored in one
4757 // processor operation but an i64 (which is not legal) requires two. So the
4758 // transform should not be done in this case.
4759 if (Value.getOpcode() != ISD::TargetConstantFP) {
4761 switch (CFP->getValueType(0).getSimpleVT()) {
4762 default: assert(0 && "Unknown FP type");
4763 case MVT::f80: // We don't do this for these yet.
4768 if (((TLI.isTypeLegal(MVT::i32) || !LegalTypes) && !LegalOperations &&
4769 !ST->isVolatile()) ||
4770 TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i32)) {
4771 Tmp = DAG.getConstant((uint32_t)CFP->getValueAPF().
4772 bitcastToAPInt().getZExtValue(), MVT::i32);
4773 return DAG.getStore(Chain, Tmp, Ptr, ST->getSrcValue(),
4774 ST->getSrcValueOffset(), ST->isVolatile(),
4775 ST->getAlignment());
4779 if (((TLI.isTypeLegal(MVT::i64) || !LegalTypes) && !LegalOperations &&
4780 !ST->isVolatile()) ||
4781 TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i64)) {
4782 Tmp = DAG.getConstant(CFP->getValueAPF().bitcastToAPInt().
4783 getZExtValue(), MVT::i64);
4784 return DAG.getStore(Chain, Tmp, Ptr, ST->getSrcValue(),
4785 ST->getSrcValueOffset(), ST->isVolatile(),
4786 ST->getAlignment());
4787 } else if (!ST->isVolatile() &&
4788 TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i32)) {
4789 // Many FP stores are not made apparent until after legalize, e.g. for
4790 // argument passing. Since this is so common, custom legalize the
4791 // 64-bit integer store into two 32-bit stores.
4792 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
4793 SDValue Lo = DAG.getConstant(Val & 0xFFFFFFFF, MVT::i32);
4794 SDValue Hi = DAG.getConstant(Val >> 32, MVT::i32);
4795 if (TLI.isBigEndian()) std::swap(Lo, Hi);
4797 int SVOffset = ST->getSrcValueOffset();
4798 unsigned Alignment = ST->getAlignment();
4799 bool isVolatile = ST->isVolatile();
4801 SDValue St0 = DAG.getStore(Chain, Lo, Ptr, ST->getSrcValue(),
4802 ST->getSrcValueOffset(),
4803 isVolatile, ST->getAlignment());
4804 Ptr = DAG.getNode(ISD::ADD, Ptr.getValueType(), Ptr,
4805 DAG.getConstant(4, Ptr.getValueType()));
4807 Alignment = MinAlign(Alignment, 4U);
4808 SDValue St1 = DAG.getStore(Chain, Hi, Ptr, ST->getSrcValue(),
4809 SVOffset, isVolatile, Alignment);
4810 return DAG.getNode(ISD::TokenFactor, MVT::Other, St0, St1);
4818 // Walk up chain skipping non-aliasing memory nodes.
4819 SDValue BetterChain = FindBetterChain(N, Chain);
4821 // If there is a better chain.
4822 if (Chain != BetterChain) {
4823 // Replace the chain to avoid dependency.
4825 if (ST->isTruncatingStore()) {
4826 ReplStore = DAG.getTruncStore(BetterChain, Value, Ptr,
4827 ST->getSrcValue(),ST->getSrcValueOffset(),
4829 ST->isVolatile(), ST->getAlignment());
4831 ReplStore = DAG.getStore(BetterChain, Value, Ptr,
4832 ST->getSrcValue(), ST->getSrcValueOffset(),
4833 ST->isVolatile(), ST->getAlignment());
4836 // Create token to keep both nodes around.
4838 DAG.getNode(ISD::TokenFactor, MVT::Other, Chain, ReplStore);
4840 // Don't add users to work list.
4841 return CombineTo(N, Token, false);
4845 // Try transforming N to an indexed store.
4846 if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N))
4847 return SDValue(N, 0);
4849 // FIXME: is there such a thing as a truncating indexed store?
4850 if (ST->isTruncatingStore() && ST->isUnindexed() &&
4851 Value.getValueType().isInteger()) {
4852 // See if we can simplify the input to this truncstore with knowledge that
4853 // only the low bits are being used. For example:
4854 // "truncstore (or (shl x, 8), y), i8" -> "truncstore y, i8"
4856 GetDemandedBits(Value,
4857 APInt::getLowBitsSet(Value.getValueSizeInBits(),
4858 ST->getMemoryVT().getSizeInBits()));
4859 AddToWorkList(Value.getNode());
4860 if (Shorter.getNode())
4861 return DAG.getTruncStore(Chain, Shorter, Ptr, ST->getSrcValue(),
4862 ST->getSrcValueOffset(), ST->getMemoryVT(),
4863 ST->isVolatile(), ST->getAlignment());
4865 // Otherwise, see if we can simplify the operation with
4866 // SimplifyDemandedBits, which only works if the value has a single use.
4867 if (SimplifyDemandedBits(Value,
4868 APInt::getLowBitsSet(
4869 Value.getValueSizeInBits(),
4870 ST->getMemoryVT().getSizeInBits())))
4871 return SDValue(N, 0);
4874 // If this is a load followed by a store to the same location, then the store
4876 if (LoadSDNode *Ld = dyn_cast<LoadSDNode>(Value)) {
4877 if (Ld->getBasePtr() == Ptr && ST->getMemoryVT() == Ld->getMemoryVT() &&
4878 ST->isUnindexed() && !ST->isVolatile() &&
4879 // There can't be any side effects between the load and store, such as
4881 Chain.reachesChainWithoutSideEffects(SDValue(Ld, 1))) {
4882 // The store is dead, remove it.
4887 // If this is an FP_ROUND or TRUNC followed by a store, fold this into a
4888 // truncating store. We can do this even if this is already a truncstore.
4889 if ((Value.getOpcode() == ISD::FP_ROUND || Value.getOpcode() == ISD::TRUNCATE)
4890 && Value.getNode()->hasOneUse() && ST->isUnindexed() &&
4891 TLI.isTruncStoreLegal(Value.getOperand(0).getValueType(),
4892 ST->getMemoryVT())) {
4893 return DAG.getTruncStore(Chain, Value.getOperand(0), Ptr, ST->getSrcValue(),
4894 ST->getSrcValueOffset(), ST->getMemoryVT(),
4895 ST->isVolatile(), ST->getAlignment());
4901 SDValue DAGCombiner::visitINSERT_VECTOR_ELT(SDNode *N) {
4902 SDValue InVec = N->getOperand(0);
4903 SDValue InVal = N->getOperand(1);
4904 SDValue EltNo = N->getOperand(2);
4906 // If the invec is a BUILD_VECTOR and if EltNo is a constant, build a new
4907 // vector with the inserted element.
4908 if (InVec.getOpcode() == ISD::BUILD_VECTOR && isa<ConstantSDNode>(EltNo)) {
4909 unsigned Elt = cast<ConstantSDNode>(EltNo)->getZExtValue();
4910 SmallVector<SDValue, 8> Ops(InVec.getNode()->op_begin(),
4911 InVec.getNode()->op_end());
4912 if (Elt < Ops.size())
4914 return DAG.getNode(ISD::BUILD_VECTOR, InVec.getValueType(),
4915 &Ops[0], Ops.size());
4921 SDValue DAGCombiner::visitEXTRACT_VECTOR_ELT(SDNode *N) {
4922 // (vextract (scalar_to_vector val, 0) -> val
4923 SDValue InVec = N->getOperand(0);
4925 if (InVec.getOpcode() == ISD::SCALAR_TO_VECTOR)
4926 return InVec.getOperand(0);
4928 // Perform only after legalization to ensure build_vector / vector_shuffle
4929 // optimizations have already been done.
4930 if (!LegalOperations) return SDValue();
4932 // (vextract (v4f32 load $addr), c) -> (f32 load $addr+c*size)
4933 // (vextract (v4f32 s2v (f32 load $addr)), c) -> (f32 load $addr+c*size)
4934 // (vextract (v4f32 shuffle (load $addr), <1,u,u,u>), 0) -> (f32 load $addr)
4935 SDValue EltNo = N->getOperand(1);
4937 if (isa<ConstantSDNode>(EltNo)) {
4938 unsigned Elt = cast<ConstantSDNode>(EltNo)->getZExtValue();
4939 bool NewLoad = false;
4940 bool BCNumEltsChanged = false;
4941 MVT VT = InVec.getValueType();
4942 MVT EVT = VT.getVectorElementType();
4944 if (InVec.getOpcode() == ISD::BIT_CONVERT) {
4945 MVT BCVT = InVec.getOperand(0).getValueType();
4946 if (!BCVT.isVector() || EVT.bitsGT(BCVT.getVectorElementType()))
4948 if (VT.getVectorNumElements() != BCVT.getVectorNumElements())
4949 BCNumEltsChanged = true;
4950 InVec = InVec.getOperand(0);
4951 EVT = BCVT.getVectorElementType();
4955 LoadSDNode *LN0 = NULL;
4956 if (ISD::isNormalLoad(InVec.getNode()))
4957 LN0 = cast<LoadSDNode>(InVec);
4958 else if (InVec.getOpcode() == ISD::SCALAR_TO_VECTOR &&
4959 InVec.getOperand(0).getValueType() == EVT &&
4960 ISD::isNormalLoad(InVec.getOperand(0).getNode())) {
4961 LN0 = cast<LoadSDNode>(InVec.getOperand(0));
4962 } else if (InVec.getOpcode() == ISD::VECTOR_SHUFFLE) {
4963 // (vextract (vector_shuffle (load $addr), v2, <1, u, u, u>), 1)
4965 // (load $addr+1*size)
4967 // If the bit convert changed the number of elements, it is unsafe
4968 // to examine the mask.
4969 if (BCNumEltsChanged)
4971 unsigned Idx = cast<ConstantSDNode>(InVec.getOperand(2).
4972 getOperand(Elt))->getZExtValue();
4973 unsigned NumElems = InVec.getOperand(2).getNumOperands();
4974 InVec = (Idx < NumElems) ? InVec.getOperand(0) : InVec.getOperand(1);
4975 if (InVec.getOpcode() == ISD::BIT_CONVERT)
4976 InVec = InVec.getOperand(0);
4977 if (ISD::isNormalLoad(InVec.getNode())) {
4978 LN0 = cast<LoadSDNode>(InVec);
4979 Elt = (Idx < NumElems) ? Idx : Idx - NumElems;
4982 if (!LN0 || !LN0->hasOneUse() || LN0->isVolatile())
4985 unsigned Align = LN0->getAlignment();
4987 // Check the resultant load doesn't need a higher alignment than the
4989 unsigned NewAlign = TLI.getTargetData()->
4990 getABITypeAlignment(LVT.getTypeForMVT());
4991 if (NewAlign > Align || !TLI.isOperationLegalOrCustom(ISD::LOAD, LVT))
4996 SDValue NewPtr = LN0->getBasePtr();
4998 unsigned PtrOff = LVT.getSizeInBits() * Elt / 8;
4999 MVT PtrType = NewPtr.getValueType();
5000 if (TLI.isBigEndian())
5001 PtrOff = VT.getSizeInBits() / 8 - PtrOff;
5002 NewPtr = DAG.getNode(ISD::ADD, PtrType, NewPtr,
5003 DAG.getConstant(PtrOff, PtrType));
5005 return DAG.getLoad(LVT, LN0->getChain(), NewPtr,
5006 LN0->getSrcValue(), LN0->getSrcValueOffset(),
5007 LN0->isVolatile(), Align);
5013 SDValue DAGCombiner::visitBUILD_VECTOR(SDNode *N) {
5014 unsigned NumInScalars = N->getNumOperands();
5015 MVT VT = N->getValueType(0);
5016 unsigned NumElts = VT.getVectorNumElements();
5017 MVT EltType = VT.getVectorElementType();
5019 // Check to see if this is a BUILD_VECTOR of a bunch of EXTRACT_VECTOR_ELT
5020 // operations. If so, and if the EXTRACT_VECTOR_ELT vector inputs come from
5021 // at most two distinct vectors, turn this into a shuffle node.
5022 SDValue VecIn1, VecIn2;
5023 for (unsigned i = 0; i != NumInScalars; ++i) {
5024 // Ignore undef inputs.
5025 if (N->getOperand(i).getOpcode() == ISD::UNDEF) continue;
5027 // If this input is something other than a EXTRACT_VECTOR_ELT with a
5028 // constant index, bail out.
5029 if (N->getOperand(i).getOpcode() != ISD::EXTRACT_VECTOR_ELT ||
5030 !isa<ConstantSDNode>(N->getOperand(i).getOperand(1))) {
5031 VecIn1 = VecIn2 = SDValue(0, 0);
5035 // If the input vector type disagrees with the result of the build_vector,
5036 // we can't make a shuffle.
5037 SDValue ExtractedFromVec = N->getOperand(i).getOperand(0);
5038 if (ExtractedFromVec.getValueType() != VT) {
5039 VecIn1 = VecIn2 = SDValue(0, 0);
5043 // Otherwise, remember this. We allow up to two distinct input vectors.
5044 if (ExtractedFromVec == VecIn1 || ExtractedFromVec == VecIn2)
5047 if (VecIn1.getNode() == 0) {
5048 VecIn1 = ExtractedFromVec;
5049 } else if (VecIn2.getNode() == 0) {
5050 VecIn2 = ExtractedFromVec;
5053 VecIn1 = VecIn2 = SDValue(0, 0);
5058 // If everything is good, we can make a shuffle operation.
5059 if (VecIn1.getNode()) {
5060 SmallVector<SDValue, 8> BuildVecIndices;
5061 for (unsigned i = 0; i != NumInScalars; ++i) {
5062 if (N->getOperand(i).getOpcode() == ISD::UNDEF) {
5063 BuildVecIndices.push_back(DAG.getNode(ISD::UNDEF, TLI.getPointerTy()));
5067 SDValue Extract = N->getOperand(i);
5069 // If extracting from the first vector, just use the index directly.
5070 if (Extract.getOperand(0) == VecIn1) {
5071 BuildVecIndices.push_back(Extract.getOperand(1));
5075 // Otherwise, use InIdx + VecSize
5077 cast<ConstantSDNode>(Extract.getOperand(1))->getZExtValue();
5078 BuildVecIndices.push_back(DAG.getIntPtrConstant(Idx+NumInScalars));
5081 // Add count and size info.
5082 MVT BuildVecVT = MVT::getVectorVT(TLI.getPointerTy(), NumElts);
5083 if (!TLI.isTypeLegal(BuildVecVT) && LegalTypes)
5086 // Return the new VECTOR_SHUFFLE node.
5089 if (VecIn2.getNode()) {
5092 // Use an undef build_vector as input for the second operand.
5093 std::vector<SDValue> UnOps(NumInScalars,
5094 DAG.getNode(ISD::UNDEF,
5096 Ops[1] = DAG.getNode(ISD::BUILD_VECTOR, VT,
5097 &UnOps[0], UnOps.size());
5098 AddToWorkList(Ops[1].getNode());
5100 Ops[2] = DAG.getNode(ISD::BUILD_VECTOR, BuildVecVT,
5101 &BuildVecIndices[0], BuildVecIndices.size());
5102 return DAG.getNode(ISD::VECTOR_SHUFFLE, VT, Ops, 3);
5108 SDValue DAGCombiner::visitCONCAT_VECTORS(SDNode *N) {
5109 // TODO: Check to see if this is a CONCAT_VECTORS of a bunch of
5110 // EXTRACT_SUBVECTOR operations. If so, and if the EXTRACT_SUBVECTOR vector
5111 // inputs come from at most two distinct vectors, turn this into a shuffle
5114 // If we only have one input vector, we don't need to do any concatenation.
5115 if (N->getNumOperands() == 1) {
5116 return N->getOperand(0);
5122 SDValue DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) {
5123 SDValue ShufMask = N->getOperand(2);
5124 unsigned NumElts = ShufMask.getNumOperands();
5126 SDValue N0 = N->getOperand(0);
5127 SDValue N1 = N->getOperand(1);
5129 assert(N0.getValueType().getVectorNumElements() == NumElts &&
5130 "Vector shuffle must be normalized in DAG");
5132 // If the shuffle mask is an identity operation on the LHS, return the LHS.
5133 bool isIdentity = true;
5134 for (unsigned i = 0; i != NumElts; ++i) {
5135 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF &&
5136 cast<ConstantSDNode>(ShufMask.getOperand(i))->getZExtValue() != i) {
5141 if (isIdentity) return N->getOperand(0);
5143 // If the shuffle mask is an identity operation on the RHS, return the RHS.
5145 for (unsigned i = 0; i != NumElts; ++i) {
5146 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF &&
5147 cast<ConstantSDNode>(ShufMask.getOperand(i))->getZExtValue() !=
5153 if (isIdentity) return N->getOperand(1);
5155 // Check if the shuffle is a unary shuffle, i.e. one of the vectors is not
5157 bool isUnary = true;
5158 bool isSplat = true;
5160 unsigned BaseIdx = 0;
5161 for (unsigned i = 0; i != NumElts; ++i)
5162 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF) {
5163 unsigned Idx=cast<ConstantSDNode>(ShufMask.getOperand(i))->getZExtValue();
5164 int V = (Idx < NumElts) ? 0 : 1;
5178 // Normalize unary shuffle so the RHS is undef.
5179 if (isUnary && VecNum == 1)
5182 // If it is a splat, check if the argument vector is a build_vector with
5183 // all scalar elements the same.
5185 SDNode *V = N0.getNode();
5187 // If this is a bit convert that changes the element type of the vector but
5188 // not the number of vector elements, look through it. Be careful not to
5189 // look though conversions that change things like v4f32 to v2f64.
5190 if (V->getOpcode() == ISD::BIT_CONVERT) {
5191 SDValue ConvInput = V->getOperand(0);
5192 if (ConvInput.getValueType().isVector() &&
5193 ConvInput.getValueType().getVectorNumElements() == NumElts)
5194 V = ConvInput.getNode();
5197 if (V->getOpcode() == ISD::BUILD_VECTOR) {
5198 unsigned NumElems = V->getNumOperands();
5199 if (NumElems > BaseIdx) {
5201 bool AllSame = true;
5202 for (unsigned i = 0; i != NumElems; ++i) {
5203 if (V->getOperand(i).getOpcode() != ISD::UNDEF) {
5204 Base = V->getOperand(i);
5208 // Splat of <u, u, u, u>, return <u, u, u, u>
5209 if (!Base.getNode())
5211 for (unsigned i = 0; i != NumElems; ++i) {
5212 if (V->getOperand(i) != Base) {
5217 // Splat of <x, x, x, x>, return <x, x, x, x>
5224 // If it is a unary or the LHS and the RHS are the same node, turn the RHS
5226 if (isUnary || N0 == N1) {
5227 // Check the SHUFFLE mask, mapping any inputs from the 2nd operand into the
5229 SmallVector<SDValue, 8> MappedOps;
5230 for (unsigned i = 0; i != NumElts; ++i) {
5231 if (ShufMask.getOperand(i).getOpcode() == ISD::UNDEF ||
5232 cast<ConstantSDNode>(ShufMask.getOperand(i))->getZExtValue() <
5234 MappedOps.push_back(ShufMask.getOperand(i));
5237 cast<ConstantSDNode>(ShufMask.getOperand(i))->getZExtValue() -
5239 MappedOps.push_back(DAG.getConstant(NewIdx,
5240 ShufMask.getOperand(i).getValueType()));
5243 ShufMask = DAG.getNode(ISD::BUILD_VECTOR, ShufMask.getValueType(),
5244 &MappedOps[0], MappedOps.size());
5245 AddToWorkList(ShufMask.getNode());
5246 return DAG.getNode(ISD::VECTOR_SHUFFLE, N->getValueType(0),
5248 DAG.getNode(ISD::UNDEF, N->getValueType(0)),
5255 /// XformToShuffleWithZero - Returns a vector_shuffle if it able to transform
5256 /// an AND to a vector_shuffle with the destination vector and a zero vector.
5257 /// e.g. AND V, <0xffffffff, 0, 0xffffffff, 0>. ==>
5258 /// vector_shuffle V, Zero, <0, 4, 2, 4>
5259 SDValue DAGCombiner::XformToShuffleWithZero(SDNode *N) {
5260 SDValue LHS = N->getOperand(0);
5261 SDValue RHS = N->getOperand(1);
5262 if (N->getOpcode() == ISD::AND) {
5263 if (RHS.getOpcode() == ISD::BIT_CONVERT)
5264 RHS = RHS.getOperand(0);
5265 if (RHS.getOpcode() == ISD::BUILD_VECTOR) {
5266 std::vector<SDValue> IdxOps;
5267 unsigned NumOps = RHS.getNumOperands();
5268 unsigned NumElts = NumOps;
5269 for (unsigned i = 0; i != NumElts; ++i) {
5270 SDValue Elt = RHS.getOperand(i);
5271 if (!isa<ConstantSDNode>(Elt))
5273 else if (cast<ConstantSDNode>(Elt)->isAllOnesValue())
5274 IdxOps.push_back(DAG.getIntPtrConstant(i));
5275 else if (cast<ConstantSDNode>(Elt)->isNullValue())
5276 IdxOps.push_back(DAG.getIntPtrConstant(NumElts));
5281 // Let's see if the target supports this vector_shuffle.
5282 if (!TLI.isVectorClearMaskLegal(IdxOps, TLI.getPointerTy(), DAG))
5285 // Return the new VECTOR_SHUFFLE node.
5286 MVT EVT = RHS.getValueType().getVectorElementType();
5287 MVT VT = MVT::getVectorVT(EVT, NumElts);
5288 MVT MaskVT = MVT::getVectorVT(TLI.getPointerTy(), NumElts);
5289 std::vector<SDValue> Ops;
5290 LHS = DAG.getNode(ISD::BIT_CONVERT, VT, LHS);
5292 AddToWorkList(LHS.getNode());
5293 std::vector<SDValue> ZeroOps(NumElts, DAG.getConstant(0, EVT));
5294 Ops.push_back(DAG.getNode(ISD::BUILD_VECTOR, VT,
5295 &ZeroOps[0], ZeroOps.size()));
5296 Ops.push_back(DAG.getNode(ISD::BUILD_VECTOR, MaskVT,
5297 &IdxOps[0], IdxOps.size()));
5298 SDValue Result = DAG.getNode(ISD::VECTOR_SHUFFLE, VT,
5299 &Ops[0], Ops.size());
5300 if (VT != N->getValueType(0))
5301 Result = DAG.getNode(ISD::BIT_CONVERT, N->getValueType(0), Result);
5308 /// SimplifyVBinOp - Visit a binary vector operation, like ADD.
5309 SDValue DAGCombiner::SimplifyVBinOp(SDNode *N) {
5310 // After legalize, the target may be depending on adds and other
5311 // binary ops to provide legal ways to construct constants or other
5312 // things. Simplifying them may result in a loss of legality.
5313 if (LegalOperations) return SDValue();
5315 MVT VT = N->getValueType(0);
5316 assert(VT.isVector() && "SimplifyVBinOp only works on vectors!");
5318 MVT EltType = VT.getVectorElementType();
5319 SDValue LHS = N->getOperand(0);
5320 SDValue RHS = N->getOperand(1);
5321 SDValue Shuffle = XformToShuffleWithZero(N);
5322 if (Shuffle.getNode()) return Shuffle;
5324 // If the LHS and RHS are BUILD_VECTOR nodes, see if we can constant fold
5326 if (LHS.getOpcode() == ISD::BUILD_VECTOR &&
5327 RHS.getOpcode() == ISD::BUILD_VECTOR) {
5328 SmallVector<SDValue, 8> Ops;
5329 for (unsigned i = 0, e = LHS.getNumOperands(); i != e; ++i) {
5330 SDValue LHSOp = LHS.getOperand(i);
5331 SDValue RHSOp = RHS.getOperand(i);
5332 // If these two elements can't be folded, bail out.
5333 if ((LHSOp.getOpcode() != ISD::UNDEF &&
5334 LHSOp.getOpcode() != ISD::Constant &&
5335 LHSOp.getOpcode() != ISD::ConstantFP) ||
5336 (RHSOp.getOpcode() != ISD::UNDEF &&
5337 RHSOp.getOpcode() != ISD::Constant &&
5338 RHSOp.getOpcode() != ISD::ConstantFP))
5340 // Can't fold divide by zero.
5341 if (N->getOpcode() == ISD::SDIV || N->getOpcode() == ISD::UDIV ||
5342 N->getOpcode() == ISD::FDIV) {
5343 if ((RHSOp.getOpcode() == ISD::Constant &&
5344 cast<ConstantSDNode>(RHSOp.getNode())->isNullValue()) ||
5345 (RHSOp.getOpcode() == ISD::ConstantFP &&
5346 cast<ConstantFPSDNode>(RHSOp.getNode())->getValueAPF().isZero()))
5349 Ops.push_back(DAG.getNode(N->getOpcode(), EltType, LHSOp, RHSOp));
5350 AddToWorkList(Ops.back().getNode());
5351 assert((Ops.back().getOpcode() == ISD::UNDEF ||
5352 Ops.back().getOpcode() == ISD::Constant ||
5353 Ops.back().getOpcode() == ISD::ConstantFP) &&
5354 "Scalar binop didn't fold!");
5357 if (Ops.size() == LHS.getNumOperands()) {
5358 MVT VT = LHS.getValueType();
5359 return DAG.getNode(ISD::BUILD_VECTOR, VT, &Ops[0], Ops.size());
5366 SDValue DAGCombiner::SimplifySelect(SDValue N0, SDValue N1, SDValue N2){
5367 assert(N0.getOpcode() ==ISD::SETCC && "First argument must be a SetCC node!");
5369 SDValue SCC = SimplifySelectCC(N0.getOperand(0), N0.getOperand(1), N1, N2,
5370 cast<CondCodeSDNode>(N0.getOperand(2))->get());
5371 // If we got a simplified select_cc node back from SimplifySelectCC, then
5372 // break it down into a new SETCC node, and a new SELECT node, and then return
5373 // the SELECT node, since we were called with a SELECT node.
5374 if (SCC.getNode()) {
5375 // Check to see if we got a select_cc back (to turn into setcc/select).
5376 // Otherwise, just return whatever node we got back, like fabs.
5377 if (SCC.getOpcode() == ISD::SELECT_CC) {
5378 SDValue SETCC = DAG.getNode(ISD::SETCC, N0.getValueType(),
5379 SCC.getOperand(0), SCC.getOperand(1),
5381 AddToWorkList(SETCC.getNode());
5382 return DAG.getNode(ISD::SELECT, SCC.getValueType(), SCC.getOperand(2),
5383 SCC.getOperand(3), SETCC);
5390 /// SimplifySelectOps - Given a SELECT or a SELECT_CC node, where LHS and RHS
5391 /// are the two values being selected between, see if we can simplify the
5392 /// select. Callers of this should assume that TheSelect is deleted if this
5393 /// returns true. As such, they should return the appropriate thing (e.g. the
5394 /// node) back to the top-level of the DAG combiner loop to avoid it being
5397 bool DAGCombiner::SimplifySelectOps(SDNode *TheSelect, SDValue LHS,
5400 // If this is a select from two identical things, try to pull the operation
5401 // through the select.
5402 if (LHS.getOpcode() == RHS.getOpcode() && LHS.hasOneUse() && RHS.hasOneUse()){
5403 // If this is a load and the token chain is identical, replace the select
5404 // of two loads with a load through a select of the address to load from.
5405 // This triggers in things like "select bool X, 10.0, 123.0" after the FP
5406 // constants have been dropped into the constant pool.
5407 if (LHS.getOpcode() == ISD::LOAD &&
5408 // Do not let this transformation reduce the number of volatile loads.
5409 !cast<LoadSDNode>(LHS)->isVolatile() &&
5410 !cast<LoadSDNode>(RHS)->isVolatile() &&
5411 // Token chains must be identical.
5412 LHS.getOperand(0) == RHS.getOperand(0)) {
5413 LoadSDNode *LLD = cast<LoadSDNode>(LHS);
5414 LoadSDNode *RLD = cast<LoadSDNode>(RHS);
5416 // If this is an EXTLOAD, the VT's must match.
5417 if (LLD->getMemoryVT() == RLD->getMemoryVT()) {
5418 // FIXME: this conflates two src values, discarding one. This is not
5419 // the right thing to do, but nothing uses srcvalues now. When they do,
5420 // turn SrcValue into a list of locations.
5422 if (TheSelect->getOpcode() == ISD::SELECT) {
5423 // Check that the condition doesn't reach either load. If so, folding
5424 // this will induce a cycle into the DAG.
5425 if (!LLD->isPredecessorOf(TheSelect->getOperand(0).getNode()) &&
5426 !RLD->isPredecessorOf(TheSelect->getOperand(0).getNode())) {
5427 Addr = DAG.getNode(ISD::SELECT, LLD->getBasePtr().getValueType(),
5428 TheSelect->getOperand(0), LLD->getBasePtr(),
5432 // Check that the condition doesn't reach either load. If so, folding
5433 // this will induce a cycle into the DAG.
5434 if (!LLD->isPredecessorOf(TheSelect->getOperand(0).getNode()) &&
5435 !RLD->isPredecessorOf(TheSelect->getOperand(0).getNode()) &&
5436 !LLD->isPredecessorOf(TheSelect->getOperand(1).getNode()) &&
5437 !RLD->isPredecessorOf(TheSelect->getOperand(1).getNode())) {
5438 Addr = DAG.getNode(ISD::SELECT_CC, LLD->getBasePtr().getValueType(),
5439 TheSelect->getOperand(0),
5440 TheSelect->getOperand(1),
5441 LLD->getBasePtr(), RLD->getBasePtr(),
5442 TheSelect->getOperand(4));
5446 if (Addr.getNode()) {
5448 if (LLD->getExtensionType() == ISD::NON_EXTLOAD)
5449 Load = DAG.getLoad(TheSelect->getValueType(0), LLD->getChain(),
5450 Addr,LLD->getSrcValue(),
5451 LLD->getSrcValueOffset(),
5453 LLD->getAlignment());
5455 Load = DAG.getExtLoad(LLD->getExtensionType(),
5456 TheSelect->getValueType(0),
5457 LLD->getChain(), Addr, LLD->getSrcValue(),
5458 LLD->getSrcValueOffset(),
5461 LLD->getAlignment());
5463 // Users of the select now use the result of the load.
5464 CombineTo(TheSelect, Load);
5466 // Users of the old loads now use the new load's chain. We know the
5467 // old-load value is dead now.
5468 CombineTo(LHS.getNode(), Load.getValue(0), Load.getValue(1));
5469 CombineTo(RHS.getNode(), Load.getValue(0), Load.getValue(1));
5479 SDValue DAGCombiner::SimplifySelectCC(SDValue N0, SDValue N1,
5480 SDValue N2, SDValue N3,
5481 ISD::CondCode CC, bool NotExtCompare) {
5483 MVT VT = N2.getValueType();
5484 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode());
5485 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2.getNode());
5486 ConstantSDNode *N3C = dyn_cast<ConstantSDNode>(N3.getNode());
5488 // Determine if the condition we're dealing with is constant
5489 SDValue SCC = SimplifySetCC(TLI.getSetCCResultType(N0.getValueType()),
5491 if (SCC.getNode()) AddToWorkList(SCC.getNode());
5492 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.getNode());
5494 // fold select_cc true, x, y -> x
5495 if (SCCC && !SCCC->isNullValue())
5497 // fold select_cc false, x, y -> y
5498 if (SCCC && SCCC->isNullValue())
5501 // Check to see if we can simplify the select into an fabs node
5502 if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N1)) {
5503 // Allow either -0.0 or 0.0
5504 if (CFP->getValueAPF().isZero()) {
5505 // select (setg[te] X, +/-0.0), X, fneg(X) -> fabs
5506 if ((CC == ISD::SETGE || CC == ISD::SETGT) &&
5507 N0 == N2 && N3.getOpcode() == ISD::FNEG &&
5508 N2 == N3.getOperand(0))
5509 return DAG.getNode(ISD::FABS, VT, N0);
5511 // select (setl[te] X, +/-0.0), fneg(X), X -> fabs
5512 if ((CC == ISD::SETLT || CC == ISD::SETLE) &&
5513 N0 == N3 && N2.getOpcode() == ISD::FNEG &&
5514 N2.getOperand(0) == N3)
5515 return DAG.getNode(ISD::FABS, VT, N3);
5519 // Check to see if we can perform the "gzip trick", transforming
5520 // select_cc setlt X, 0, A, 0 -> and (sra X, size(X)-1), A
5521 if (N1C && N3C && N3C->isNullValue() && CC == ISD::SETLT &&
5522 N0.getValueType().isInteger() &&
5523 N2.getValueType().isInteger() &&
5524 (N1C->isNullValue() || // (a < 0) ? b : 0
5525 (N1C->getAPIntValue() == 1 && N0 == N2))) { // (a < 1) ? a : 0
5526 MVT XType = N0.getValueType();
5527 MVT AType = N2.getValueType();
5528 if (XType.bitsGE(AType)) {
5529 // and (sra X, size(X)-1, A) -> "and (srl X, C2), A" iff A is a
5530 // single-bit constant.
5531 if (N2C && ((N2C->getAPIntValue() & (N2C->getAPIntValue()-1)) == 0)) {
5532 unsigned ShCtV = N2C->getAPIntValue().logBase2();
5533 ShCtV = XType.getSizeInBits()-ShCtV-1;
5534 SDValue ShCt = DAG.getConstant(ShCtV, TLI.getShiftAmountTy());
5535 SDValue Shift = DAG.getNode(ISD::SRL, XType, N0, ShCt);
5536 AddToWorkList(Shift.getNode());
5537 if (XType.bitsGT(AType)) {
5538 Shift = DAG.getNode(ISD::TRUNCATE, AType, Shift);
5539 AddToWorkList(Shift.getNode());
5541 return DAG.getNode(ISD::AND, AType, Shift, N2);
5543 SDValue Shift = DAG.getNode(ISD::SRA, XType, N0,
5544 DAG.getConstant(XType.getSizeInBits()-1,
5545 TLI.getShiftAmountTy()));
5546 AddToWorkList(Shift.getNode());
5547 if (XType.bitsGT(AType)) {
5548 Shift = DAG.getNode(ISD::TRUNCATE, AType, Shift);
5549 AddToWorkList(Shift.getNode());
5551 return DAG.getNode(ISD::AND, AType, Shift, N2);
5555 // fold select C, 16, 0 -> shl C, 4
5556 if (N2C && N3C && N3C->isNullValue() && N2C->getAPIntValue().isPowerOf2() &&
5557 TLI.getBooleanContents() == TargetLowering::ZeroOrOneBooleanContent) {
5559 // If the caller doesn't want us to simplify this into a zext of a compare,
5561 if (NotExtCompare && N2C->getAPIntValue() == 1)
5564 // Get a SetCC of the condition
5565 // FIXME: Should probably make sure that setcc is legal if we ever have a
5566 // target where it isn't.
5568 // cast from setcc result type to select result type
5570 SCC = DAG.getSetCC(TLI.getSetCCResultType(N0.getValueType()),
5572 if (N2.getValueType().bitsLT(SCC.getValueType()))
5573 Temp = DAG.getZeroExtendInReg(SCC, N2.getValueType());
5575 Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getValueType(), SCC);
5577 SCC = DAG.getSetCC(MVT::i1, N0, N1, CC);
5578 Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getValueType(), SCC);
5580 AddToWorkList(SCC.getNode());
5581 AddToWorkList(Temp.getNode());
5583 if (N2C->getAPIntValue() == 1)
5585 // shl setcc result by log2 n2c
5586 return DAG.getNode(ISD::SHL, N2.getValueType(), Temp,
5587 DAG.getConstant(N2C->getAPIntValue().logBase2(),
5588 TLI.getShiftAmountTy()));
5591 // Check to see if this is the equivalent of setcc
5592 // FIXME: Turn all of these into setcc if setcc if setcc is legal
5593 // otherwise, go ahead with the folds.
5594 if (0 && N3C && N3C->isNullValue() && N2C && (N2C->getAPIntValue() == 1ULL)) {
5595 MVT XType = N0.getValueType();
5596 if (!LegalOperations ||
5597 TLI.isOperationLegal(ISD::SETCC, TLI.getSetCCResultType(XType))) {
5598 SDValue Res = DAG.getSetCC(TLI.getSetCCResultType(XType), N0, N1, CC);
5599 if (Res.getValueType() != VT)
5600 Res = DAG.getNode(ISD::ZERO_EXTEND, VT, Res);
5604 // seteq X, 0 -> srl (ctlz X, log2(size(X)))
5605 if (N1C && N1C->isNullValue() && CC == ISD::SETEQ &&
5606 (!LegalOperations ||
5607 TLI.isOperationLegal(ISD::CTLZ, XType))) {
5608 SDValue Ctlz = DAG.getNode(ISD::CTLZ, XType, N0);
5609 return DAG.getNode(ISD::SRL, XType, Ctlz,
5610 DAG.getConstant(Log2_32(XType.getSizeInBits()),
5611 TLI.getShiftAmountTy()));
5613 // setgt X, 0 -> srl (and (-X, ~X), size(X)-1)
5614 if (N1C && N1C->isNullValue() && CC == ISD::SETGT) {
5615 SDValue NegN0 = DAG.getNode(ISD::SUB, XType, DAG.getConstant(0, XType),
5617 SDValue NotN0 = DAG.getNOT(N0, XType);
5618 return DAG.getNode(ISD::SRL, XType,
5619 DAG.getNode(ISD::AND, XType, NegN0, NotN0),
5620 DAG.getConstant(XType.getSizeInBits()-1,
5621 TLI.getShiftAmountTy()));
5623 // setgt X, -1 -> xor (srl (X, size(X)-1), 1)
5624 if (N1C && N1C->isAllOnesValue() && CC == ISD::SETGT) {
5625 SDValue Sign = DAG.getNode(ISD::SRL, XType, N0,
5626 DAG.getConstant(XType.getSizeInBits()-1,
5627 TLI.getShiftAmountTy()));
5628 return DAG.getNode(ISD::XOR, XType, Sign, DAG.getConstant(1, XType));
5632 // Check to see if this is an integer abs. select_cc setl[te] X, 0, -X, X ->
5633 // Y = sra (X, size(X)-1); xor (add (X, Y), Y)
5634 if (N1C && N1C->isNullValue() && (CC == ISD::SETLT || CC == ISD::SETLE) &&
5635 N0 == N3 && N2.getOpcode() == ISD::SUB && N0 == N2.getOperand(1) &&
5636 N2.getOperand(0) == N1 && N0.getValueType().isInteger()) {
5637 MVT XType = N0.getValueType();
5638 SDValue Shift = DAG.getNode(ISD::SRA, XType, N0,
5639 DAG.getConstant(XType.getSizeInBits()-1,
5640 TLI.getShiftAmountTy()));
5641 SDValue Add = DAG.getNode(ISD::ADD, XType, N0, Shift);
5642 AddToWorkList(Shift.getNode());
5643 AddToWorkList(Add.getNode());
5644 return DAG.getNode(ISD::XOR, XType, Add, Shift);
5646 // Check to see if this is an integer abs. select_cc setgt X, -1, X, -X ->
5647 // Y = sra (X, size(X)-1); xor (add (X, Y), Y)
5648 if (N1C && N1C->isAllOnesValue() && CC == ISD::SETGT &&
5649 N0 == N2 && N3.getOpcode() == ISD::SUB && N0 == N3.getOperand(1)) {
5650 if (ConstantSDNode *SubC = dyn_cast<ConstantSDNode>(N3.getOperand(0))) {
5651 MVT XType = N0.getValueType();
5652 if (SubC->isNullValue() && XType.isInteger()) {
5653 SDValue Shift = DAG.getNode(ISD::SRA, XType, N0,
5654 DAG.getConstant(XType.getSizeInBits()-1,
5655 TLI.getShiftAmountTy()));
5656 SDValue Add = DAG.getNode(ISD::ADD, XType, N0, Shift);
5657 AddToWorkList(Shift.getNode());
5658 AddToWorkList(Add.getNode());
5659 return DAG.getNode(ISD::XOR, XType, Add, Shift);
5667 /// SimplifySetCC - This is a stub for TargetLowering::SimplifySetCC.
5668 SDValue DAGCombiner::SimplifySetCC(MVT VT, SDValue N0,
5669 SDValue N1, ISD::CondCode Cond,
5670 bool foldBooleans) {
5671 TargetLowering::DAGCombinerInfo
5672 DagCombineInfo(DAG, Level == Unrestricted, false, this);
5673 return TLI.SimplifySetCC(VT, N0, N1, Cond, foldBooleans, DagCombineInfo);
5676 /// BuildSDIVSequence - Given an ISD::SDIV node expressing a divide by constant,
5677 /// return a DAG expression to select that will generate the same value by
5678 /// multiplying by a magic number. See:
5679 /// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
5680 SDValue DAGCombiner::BuildSDIV(SDNode *N) {
5681 std::vector<SDNode*> Built;
5682 SDValue S = TLI.BuildSDIV(N, DAG, &Built);
5684 for (std::vector<SDNode*>::iterator ii = Built.begin(), ee = Built.end();
5690 /// BuildUDIVSequence - Given an ISD::UDIV node expressing a divide by constant,
5691 /// return a DAG expression to select that will generate the same value by
5692 /// multiplying by a magic number. See:
5693 /// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
5694 SDValue DAGCombiner::BuildUDIV(SDNode *N) {
5695 std::vector<SDNode*> Built;
5696 SDValue S = TLI.BuildUDIV(N, DAG, &Built);
5698 for (std::vector<SDNode*>::iterator ii = Built.begin(), ee = Built.end();
5704 /// FindBaseOffset - Return true if base is known not to alias with anything
5705 /// but itself. Provides base object and offset as results.
5706 static bool FindBaseOffset(SDValue Ptr, SDValue &Base, int64_t &Offset) {
5707 // Assume it is a primitive operation.
5708 Base = Ptr; Offset = 0;
5710 // If it's an adding a simple constant then integrate the offset.
5711 if (Base.getOpcode() == ISD::ADD) {
5712 if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Base.getOperand(1))) {
5713 Base = Base.getOperand(0);
5714 Offset += C->getZExtValue();
5718 // If it's any of the following then it can't alias with anything but itself.
5719 return isa<FrameIndexSDNode>(Base) ||
5720 isa<ConstantPoolSDNode>(Base) ||
5721 isa<GlobalAddressSDNode>(Base);
5724 /// isAlias - Return true if there is any possibility that the two addresses
5726 bool DAGCombiner::isAlias(SDValue Ptr1, int64_t Size1,
5727 const Value *SrcValue1, int SrcValueOffset1,
5728 SDValue Ptr2, int64_t Size2,
5729 const Value *SrcValue2, int SrcValueOffset2)
5731 // If they are the same then they must be aliases.
5732 if (Ptr1 == Ptr2) return true;
5734 // Gather base node and offset information.
5735 SDValue Base1, Base2;
5736 int64_t Offset1, Offset2;
5737 bool KnownBase1 = FindBaseOffset(Ptr1, Base1, Offset1);
5738 bool KnownBase2 = FindBaseOffset(Ptr2, Base2, Offset2);
5740 // If they have a same base address then...
5741 if (Base1 == Base2) {
5742 // Check to see if the addresses overlap.
5743 return!((Offset1 + Size1) <= Offset2 || (Offset2 + Size2) <= Offset1);
5746 // If we know both bases then they can't alias.
5747 if (KnownBase1 && KnownBase2) return false;
5749 if (CombinerGlobalAA) {
5750 // Use alias analysis information.
5751 int64_t MinOffset = std::min(SrcValueOffset1, SrcValueOffset2);
5752 int64_t Overlap1 = Size1 + SrcValueOffset1 - MinOffset;
5753 int64_t Overlap2 = Size2 + SrcValueOffset2 - MinOffset;
5754 AliasAnalysis::AliasResult AAResult =
5755 AA.alias(SrcValue1, Overlap1, SrcValue2, Overlap2);
5756 if (AAResult == AliasAnalysis::NoAlias)
5760 // Otherwise we have to assume they alias.
5764 /// FindAliasInfo - Extracts the relevant alias information from the memory
5765 /// node. Returns true if the operand was a load.
5766 bool DAGCombiner::FindAliasInfo(SDNode *N,
5767 SDValue &Ptr, int64_t &Size,
5768 const Value *&SrcValue, int &SrcValueOffset) {
5769 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) {
5770 Ptr = LD->getBasePtr();
5771 Size = LD->getMemoryVT().getSizeInBits() >> 3;
5772 SrcValue = LD->getSrcValue();
5773 SrcValueOffset = LD->getSrcValueOffset();
5775 } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) {
5776 Ptr = ST->getBasePtr();
5777 Size = ST->getMemoryVT().getSizeInBits() >> 3;
5778 SrcValue = ST->getSrcValue();
5779 SrcValueOffset = ST->getSrcValueOffset();
5781 assert(0 && "FindAliasInfo expected a memory operand");
5787 /// GatherAllAliases - Walk up chain skipping non-aliasing memory nodes,
5788 /// looking for aliasing nodes and adding them to the Aliases vector.
5789 void DAGCombiner::GatherAllAliases(SDNode *N, SDValue OriginalChain,
5790 SmallVector<SDValue, 8> &Aliases) {
5791 SmallVector<SDValue, 8> Chains; // List of chains to visit.
5792 std::set<SDNode *> Visited; // Visited node set.
5794 // Get alias information for node.
5797 const Value *SrcValue;
5799 bool IsLoad = FindAliasInfo(N, Ptr, Size, SrcValue, SrcValueOffset);
5802 Chains.push_back(OriginalChain);
5804 // Look at each chain and determine if it is an alias. If so, add it to the
5805 // aliases list. If not, then continue up the chain looking for the next
5807 while (!Chains.empty()) {
5808 SDValue Chain = Chains.back();
5811 // Don't bother if we've been before.
5812 if (Visited.find(Chain.getNode()) != Visited.end()) continue;
5813 Visited.insert(Chain.getNode());
5815 switch (Chain.getOpcode()) {
5816 case ISD::EntryToken:
5817 // Entry token is ideal chain operand, but handled in FindBetterChain.
5822 // Get alias information for Chain.
5825 const Value *OpSrcValue;
5826 int OpSrcValueOffset;
5827 bool IsOpLoad = FindAliasInfo(Chain.getNode(), OpPtr, OpSize,
5828 OpSrcValue, OpSrcValueOffset);
5830 // If chain is alias then stop here.
5831 if (!(IsLoad && IsOpLoad) &&
5832 isAlias(Ptr, Size, SrcValue, SrcValueOffset,
5833 OpPtr, OpSize, OpSrcValue, OpSrcValueOffset)) {
5834 Aliases.push_back(Chain);
5836 // Look further up the chain.
5837 Chains.push_back(Chain.getOperand(0));
5838 // Clean up old chain.
5839 AddToWorkList(Chain.getNode());
5844 case ISD::TokenFactor:
5845 // We have to check each of the operands of the token factor, so we queue
5846 // then up. Adding the operands to the queue (stack) in reverse order
5847 // maintains the original order and increases the likelihood that getNode
5848 // will find a matching token factor (CSE.)
5849 for (unsigned n = Chain.getNumOperands(); n;)
5850 Chains.push_back(Chain.getOperand(--n));
5851 // Eliminate the token factor if we can.
5852 AddToWorkList(Chain.getNode());
5856 // For all other instructions we will just have to take what we can get.
5857 Aliases.push_back(Chain);
5863 /// FindBetterChain - Walk up chain skipping non-aliasing memory nodes, looking
5864 /// for a better chain (aliasing node.)
5865 SDValue DAGCombiner::FindBetterChain(SDNode *N, SDValue OldChain) {
5866 SmallVector<SDValue, 8> Aliases; // Ops for replacing token factor.
5868 // Accumulate all the aliases to this node.
5869 GatherAllAliases(N, OldChain, Aliases);
5871 if (Aliases.size() == 0) {
5872 // If no operands then chain to entry token.
5873 return DAG.getEntryNode();
5874 } else if (Aliases.size() == 1) {
5875 // If a single operand then chain to it. We don't need to revisit it.
5879 // Construct a custom tailored token factor.
5880 SDValue NewChain = DAG.getNode(ISD::TokenFactor, MVT::Other,
5881 &Aliases[0], Aliases.size());
5883 // Make sure the old chain gets cleaned up.
5884 if (NewChain != OldChain) AddToWorkList(OldChain.getNode());
5889 // SelectionDAG::Combine - This is the entry point for the file.
5891 void SelectionDAG::Combine(CombineLevel Level, AliasAnalysis &AA, bool Fast) {
5892 /// run - This is the main entry point to this class.
5894 DAGCombiner(*this, AA, Fast).Run(Level);