1 //===-- DAGCombiner.cpp - Implement a DAG node combiner -------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by Nate Begeman and is distributed under the
6 // University of Illinois Open Source 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 // FIXME: Missing folds
14 // sdiv, udiv, srem, urem (X, const) where X is an integer can be expanded into
15 // a sequence of multiplies, shifts, and adds. This should be controlled by
16 // some kind of hint from the target that int div is expensive.
17 // various folds of mulh[s,u] by constants such as -1, powers of 2, etc.
19 // FIXME: select C, pow2, pow2 -> something smart
20 // FIXME: trunc(select X, Y, Z) -> select X, trunc(Y), trunc(Z)
21 // FIXME: Dead stores -> nuke
22 // FIXME: shr X, (and Y,31) -> shr X, Y (TRICKY!)
23 // FIXME: mul (x, const) -> shifts + adds
24 // FIXME: undef values
25 // FIXME: divide by zero is currently left unfolded. do we want to turn this
27 // FIXME: select ne (select cc, 1, 0), 0, true, false -> select cc, true, false
29 //===----------------------------------------------------------------------===//
31 #define DEBUG_TYPE "dagcombine"
32 #include "llvm/ADT/Statistic.h"
33 #include "llvm/Analysis/AliasAnalysis.h"
34 #include "llvm/CodeGen/SelectionDAG.h"
35 #include "llvm/Support/Debug.h"
36 #include "llvm/Support/MathExtras.h"
37 #include "llvm/Target/TargetLowering.h"
38 #include "llvm/Support/Compiler.h"
39 #include "llvm/Support/CommandLine.h"
47 static Statistic<> NodesCombined ("dagcombiner",
48 "Number of dag nodes combined");
51 CombinerAA("combiner-alias-analysis", cl::Hidden,
52 cl::desc("Turn on alias analysis during testing"));
55 CombinerGlobalAA("combiner-global-alias-analysis", cl::Hidden,
56 cl::desc("Include global information in alias analysis"));
58 //------------------------------ DAGCombiner ---------------------------------//
60 class VISIBILITY_HIDDEN DAGCombiner {
65 // Worklist of all of the nodes that need to be simplified.
66 std::vector<SDNode*> WorkList;
68 // AA - Used for DAG load/store alias analysis.
71 /// AddUsersToWorkList - When an instruction is simplified, add all users of
72 /// the instruction to the work lists because they might get more simplified
75 void AddUsersToWorkList(SDNode *N) {
76 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end();
81 /// removeFromWorkList - remove all instances of N from the worklist.
83 void removeFromWorkList(SDNode *N) {
84 WorkList.erase(std::remove(WorkList.begin(), WorkList.end(), N),
89 /// AddToWorkList - Add to the work list making sure it's instance is at the
90 /// the back (next to be processed.)
91 void AddToWorkList(SDNode *N) {
92 removeFromWorkList(N);
93 WorkList.push_back(N);
96 SDOperand CombineTo(SDNode *N, const SDOperand *To, unsigned NumTo,
98 assert(N->getNumValues() == NumTo && "Broken CombineTo call!");
100 DEBUG(std::cerr << "\nReplacing.1 "; N->dump();
101 std::cerr << "\nWith: "; To[0].Val->dump(&DAG);
102 std::cerr << " and " << NumTo-1 << " other values\n");
103 std::vector<SDNode*> NowDead;
104 DAG.ReplaceAllUsesWith(N, To, &NowDead);
107 // Push the new nodes and any users onto the worklist
108 for (unsigned i = 0, e = NumTo; i != e; ++i) {
109 AddToWorkList(To[i].Val);
110 AddUsersToWorkList(To[i].Val);
114 // Nodes can be reintroduced into the worklist. Make sure we do not
115 // process a node that has been replaced.
116 removeFromWorkList(N);
117 for (unsigned i = 0, e = NowDead.size(); i != e; ++i)
118 removeFromWorkList(NowDead[i]);
120 // Finally, since the node is now dead, remove it from the graph.
122 return SDOperand(N, 0);
125 SDOperand CombineTo(SDNode *N, SDOperand Res, bool AddTo = true) {
126 return CombineTo(N, &Res, 1, AddTo);
129 SDOperand CombineTo(SDNode *N, SDOperand Res0, SDOperand Res1,
131 SDOperand To[] = { Res0, Res1 };
132 return CombineTo(N, To, 2, AddTo);
136 /// SimplifyDemandedBits - Check the specified integer node value to see if
137 /// it can be simplified or if things it uses can be simplified by bit
138 /// propagation. If so, return true.
139 bool SimplifyDemandedBits(SDOperand Op) {
140 TargetLowering::TargetLoweringOpt TLO(DAG);
141 uint64_t KnownZero, KnownOne;
142 uint64_t Demanded = MVT::getIntVTBitMask(Op.getValueType());
143 if (!TLI.SimplifyDemandedBits(Op, Demanded, KnownZero, KnownOne, TLO))
147 AddToWorkList(Op.Val);
149 // Replace the old value with the new one.
151 DEBUG(std::cerr << "\nReplacing.2 "; TLO.Old.Val->dump();
152 std::cerr << "\nWith: "; TLO.New.Val->dump(&DAG);
155 std::vector<SDNode*> NowDead;
156 DAG.ReplaceAllUsesOfValueWith(TLO.Old, TLO.New, NowDead);
158 // Push the new node and any (possibly new) users onto the worklist.
159 AddToWorkList(TLO.New.Val);
160 AddUsersToWorkList(TLO.New.Val);
162 // Nodes can end up on the worklist more than once. Make sure we do
163 // not process a node that has been replaced.
164 for (unsigned i = 0, e = NowDead.size(); i != e; ++i)
165 removeFromWorkList(NowDead[i]);
167 // Finally, if the node is now dead, remove it from the graph. The node
168 // may not be dead if the replacement process recursively simplified to
169 // something else needing this node.
170 if (TLO.Old.Val->use_empty()) {
171 removeFromWorkList(TLO.Old.Val);
172 DAG.DeleteNode(TLO.Old.Val);
177 /// visit - call the node-specific routine that knows how to fold each
178 /// particular type of node.
179 SDOperand visit(SDNode *N);
181 // Visitation implementation - Implement dag node combining for different
182 // node types. The semantics are as follows:
184 // SDOperand.Val == 0 - No change was made
185 // SDOperand.Val == N - N was replaced, is dead, and is already handled.
186 // otherwise - N should be replaced by the returned Operand.
188 SDOperand visitTokenFactor(SDNode *N);
189 SDOperand visitADD(SDNode *N);
190 SDOperand visitSUB(SDNode *N);
191 SDOperand visitMUL(SDNode *N);
192 SDOperand visitSDIV(SDNode *N);
193 SDOperand visitUDIV(SDNode *N);
194 SDOperand visitSREM(SDNode *N);
195 SDOperand visitUREM(SDNode *N);
196 SDOperand visitMULHU(SDNode *N);
197 SDOperand visitMULHS(SDNode *N);
198 SDOperand visitAND(SDNode *N);
199 SDOperand visitOR(SDNode *N);
200 SDOperand visitXOR(SDNode *N);
201 SDOperand visitVBinOp(SDNode *N, ISD::NodeType IntOp, ISD::NodeType FPOp);
202 SDOperand visitSHL(SDNode *N);
203 SDOperand visitSRA(SDNode *N);
204 SDOperand visitSRL(SDNode *N);
205 SDOperand visitCTLZ(SDNode *N);
206 SDOperand visitCTTZ(SDNode *N);
207 SDOperand visitCTPOP(SDNode *N);
208 SDOperand visitSELECT(SDNode *N);
209 SDOperand visitSELECT_CC(SDNode *N);
210 SDOperand visitSETCC(SDNode *N);
211 SDOperand visitSIGN_EXTEND(SDNode *N);
212 SDOperand visitZERO_EXTEND(SDNode *N);
213 SDOperand visitANY_EXTEND(SDNode *N);
214 SDOperand visitSIGN_EXTEND_INREG(SDNode *N);
215 SDOperand visitTRUNCATE(SDNode *N);
216 SDOperand visitBIT_CONVERT(SDNode *N);
217 SDOperand visitVBIT_CONVERT(SDNode *N);
218 SDOperand visitFADD(SDNode *N);
219 SDOperand visitFSUB(SDNode *N);
220 SDOperand visitFMUL(SDNode *N);
221 SDOperand visitFDIV(SDNode *N);
222 SDOperand visitFREM(SDNode *N);
223 SDOperand visitFCOPYSIGN(SDNode *N);
224 SDOperand visitSINT_TO_FP(SDNode *N);
225 SDOperand visitUINT_TO_FP(SDNode *N);
226 SDOperand visitFP_TO_SINT(SDNode *N);
227 SDOperand visitFP_TO_UINT(SDNode *N);
228 SDOperand visitFP_ROUND(SDNode *N);
229 SDOperand visitFP_ROUND_INREG(SDNode *N);
230 SDOperand visitFP_EXTEND(SDNode *N);
231 SDOperand visitFNEG(SDNode *N);
232 SDOperand visitFABS(SDNode *N);
233 SDOperand visitBRCOND(SDNode *N);
234 SDOperand visitBR_CC(SDNode *N);
235 SDOperand visitLOAD(SDNode *N);
236 SDOperand visitSTORE(SDNode *N);
237 SDOperand visitINSERT_VECTOR_ELT(SDNode *N);
238 SDOperand visitVINSERT_VECTOR_ELT(SDNode *N);
239 SDOperand visitVBUILD_VECTOR(SDNode *N);
240 SDOperand visitVECTOR_SHUFFLE(SDNode *N);
241 SDOperand visitVVECTOR_SHUFFLE(SDNode *N);
243 SDOperand XformToShuffleWithZero(SDNode *N);
244 SDOperand ReassociateOps(unsigned Opc, SDOperand LHS, SDOperand RHS);
246 bool SimplifySelectOps(SDNode *SELECT, SDOperand LHS, SDOperand RHS);
247 SDOperand SimplifyBinOpWithSameOpcodeHands(SDNode *N);
248 SDOperand SimplifySelect(SDOperand N0, SDOperand N1, SDOperand N2);
249 SDOperand SimplifySelectCC(SDOperand N0, SDOperand N1, SDOperand N2,
250 SDOperand N3, ISD::CondCode CC);
251 SDOperand SimplifySetCC(MVT::ValueType VT, SDOperand N0, SDOperand N1,
252 ISD::CondCode Cond, bool foldBooleans = true);
253 SDOperand ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(SDNode *, MVT::ValueType);
254 SDOperand BuildSDIV(SDNode *N);
255 SDOperand BuildUDIV(SDNode *N);
256 SDNode *MatchRotate(SDOperand LHS, SDOperand RHS);
258 /// GatherAllAliases - Walk up chain skipping non-aliasing memory nodes,
259 /// looking for aliasing nodes and adding them to the Aliases vector.
260 void GatherAllAliases(SDNode *N, SDOperand OriginalChain,
261 SmallVector<SDOperand, 8> &Aliases);
263 /// isAlias - Return true if there is any possibility that the two addresses
265 bool isAlias(SDOperand Ptr1, int64_t Size1,
266 const Value *SrcValue1, int SrcValueOffset1,
267 SDOperand Ptr2, int64_t Size2,
268 const Value *SrcValue2, int SrcValueOffset1);
270 /// FindAliasInfo - Extracts the relevant alias information from the memory
271 /// node. Returns true if the operand was a load.
272 bool FindAliasInfo(SDNode *N,
273 SDOperand &Ptr, int64_t &Size,
274 const Value *&SrcValue, int &SrcValueOffset);
276 /// FindBetterChain - Walk up chain skipping non-aliasing memory nodes,
277 /// looking for a better chain (aliasing node.)
278 SDOperand FindBetterChain(SDNode *N, SDOperand Chain);
281 DAGCombiner(SelectionDAG &D, AliasAnalysis &A)
283 TLI(D.getTargetLoweringInfo()),
284 AfterLegalize(false),
287 /// Run - runs the dag combiner on all nodes in the work list
288 void Run(bool RunningAfterLegalize);
292 //===----------------------------------------------------------------------===//
293 // TargetLowering::DAGCombinerInfo implementation
294 //===----------------------------------------------------------------------===//
296 void TargetLowering::DAGCombinerInfo::AddToWorklist(SDNode *N) {
297 ((DAGCombiner*)DC)->AddToWorkList(N);
300 SDOperand TargetLowering::DAGCombinerInfo::
301 CombineTo(SDNode *N, const std::vector<SDOperand> &To) {
302 return ((DAGCombiner*)DC)->CombineTo(N, &To[0], To.size());
305 SDOperand TargetLowering::DAGCombinerInfo::
306 CombineTo(SDNode *N, SDOperand Res) {
307 return ((DAGCombiner*)DC)->CombineTo(N, Res);
311 SDOperand TargetLowering::DAGCombinerInfo::
312 CombineTo(SDNode *N, SDOperand Res0, SDOperand Res1) {
313 return ((DAGCombiner*)DC)->CombineTo(N, Res0, Res1);
319 //===----------------------------------------------------------------------===//
322 // isSetCCEquivalent - Return true if this node is a setcc, or is a select_cc
323 // that selects between the values 1 and 0, making it equivalent to a setcc.
324 // Also, set the incoming LHS, RHS, and CC references to the appropriate
325 // nodes based on the type of node we are checking. This simplifies life a
326 // bit for the callers.
327 static bool isSetCCEquivalent(SDOperand N, SDOperand &LHS, SDOperand &RHS,
329 if (N.getOpcode() == ISD::SETCC) {
330 LHS = N.getOperand(0);
331 RHS = N.getOperand(1);
332 CC = N.getOperand(2);
335 if (N.getOpcode() == ISD::SELECT_CC &&
336 N.getOperand(2).getOpcode() == ISD::Constant &&
337 N.getOperand(3).getOpcode() == ISD::Constant &&
338 cast<ConstantSDNode>(N.getOperand(2))->getValue() == 1 &&
339 cast<ConstantSDNode>(N.getOperand(3))->isNullValue()) {
340 LHS = N.getOperand(0);
341 RHS = N.getOperand(1);
342 CC = N.getOperand(4);
348 // isOneUseSetCC - Return true if this is a SetCC-equivalent operation with only
349 // one use. If this is true, it allows the users to invert the operation for
350 // free when it is profitable to do so.
351 static bool isOneUseSetCC(SDOperand N) {
352 SDOperand N0, N1, N2;
353 if (isSetCCEquivalent(N, N0, N1, N2) && N.Val->hasOneUse())
358 SDOperand DAGCombiner::ReassociateOps(unsigned Opc, SDOperand N0, SDOperand N1){
359 MVT::ValueType VT = N0.getValueType();
360 // reassoc. (op (op x, c1), y) -> (op (op x, y), c1) iff x+c1 has one use
361 // reassoc. (op (op x, c1), c2) -> (op x, (op c1, c2))
362 if (N0.getOpcode() == Opc && isa<ConstantSDNode>(N0.getOperand(1))) {
363 if (isa<ConstantSDNode>(N1)) {
364 SDOperand OpNode = DAG.getNode(Opc, VT, N0.getOperand(1), N1);
365 AddToWorkList(OpNode.Val);
366 return DAG.getNode(Opc, VT, OpNode, N0.getOperand(0));
367 } else if (N0.hasOneUse()) {
368 SDOperand OpNode = DAG.getNode(Opc, VT, N0.getOperand(0), N1);
369 AddToWorkList(OpNode.Val);
370 return DAG.getNode(Opc, VT, OpNode, N0.getOperand(1));
373 // reassoc. (op y, (op x, c1)) -> (op (op x, y), c1) iff x+c1 has one use
374 // reassoc. (op c2, (op x, c1)) -> (op x, (op c1, c2))
375 if (N1.getOpcode() == Opc && isa<ConstantSDNode>(N1.getOperand(1))) {
376 if (isa<ConstantSDNode>(N0)) {
377 SDOperand OpNode = DAG.getNode(Opc, VT, N1.getOperand(1), N0);
378 AddToWorkList(OpNode.Val);
379 return DAG.getNode(Opc, VT, OpNode, N1.getOperand(0));
380 } else if (N1.hasOneUse()) {
381 SDOperand OpNode = DAG.getNode(Opc, VT, N1.getOperand(0), N0);
382 AddToWorkList(OpNode.Val);
383 return DAG.getNode(Opc, VT, OpNode, N1.getOperand(1));
389 void DAGCombiner::Run(bool RunningAfterLegalize) {
390 // set the instance variable, so that the various visit routines may use it.
391 AfterLegalize = RunningAfterLegalize;
393 // Add all the dag nodes to the worklist.
394 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(),
395 E = DAG.allnodes_end(); I != E; ++I)
396 WorkList.push_back(I);
398 // Create a dummy node (which is not added to allnodes), that adds a reference
399 // to the root node, preventing it from being deleted, and tracking any
400 // changes of the root.
401 HandleSDNode Dummy(DAG.getRoot());
403 // The root of the dag may dangle to deleted nodes until the dag combiner is
404 // done. Set it to null to avoid confusion.
405 DAG.setRoot(SDOperand());
407 /// DagCombineInfo - Expose the DAG combiner to the target combiner impls.
408 TargetLowering::DAGCombinerInfo
409 DagCombineInfo(DAG, !RunningAfterLegalize, this);
411 // while the worklist isn't empty, inspect the node on the end of it and
412 // try and combine it.
413 while (!WorkList.empty()) {
414 SDNode *N = WorkList.back();
417 // If N has no uses, it is dead. Make sure to revisit all N's operands once
418 // N is deleted from the DAG, since they too may now be dead or may have a
419 // reduced number of uses, allowing other xforms.
420 if (N->use_empty() && N != &Dummy) {
421 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
422 AddToWorkList(N->getOperand(i).Val);
428 SDOperand RV = visit(N);
430 // If nothing happened, try a target-specific DAG combine.
432 assert(N->getOpcode() != ISD::DELETED_NODE &&
433 "Node was deleted but visit returned NULL!");
434 if (N->getOpcode() >= ISD::BUILTIN_OP_END ||
435 TLI.hasTargetDAGCombine((ISD::NodeType)N->getOpcode()))
436 RV = TLI.PerformDAGCombine(N, DagCombineInfo);
441 // If we get back the same node we passed in, rather than a new node or
442 // zero, we know that the node must have defined multiple values and
443 // CombineTo was used. Since CombineTo takes care of the worklist
444 // mechanics for us, we have no work to do in this case.
446 assert(N->getOpcode() != ISD::DELETED_NODE &&
447 RV.Val->getOpcode() != ISD::DELETED_NODE &&
448 "Node was deleted but visit returned new node!");
450 DEBUG(std::cerr << "\nReplacing.3 "; N->dump();
451 std::cerr << "\nWith: "; RV.Val->dump(&DAG);
453 std::vector<SDNode*> NowDead;
454 if (N->getNumValues() == RV.Val->getNumValues())
455 DAG.ReplaceAllUsesWith(N, RV.Val, &NowDead);
457 assert(N->getValueType(0) == RV.getValueType() && "Type mismatch");
459 DAG.ReplaceAllUsesWith(N, &OpV, &NowDead);
462 // Push the new node and any users onto the worklist
463 AddToWorkList(RV.Val);
464 AddUsersToWorkList(RV.Val);
466 // Nodes can be reintroduced into the worklist. Make sure we do not
467 // process a node that has been replaced.
468 removeFromWorkList(N);
469 for (unsigned i = 0, e = NowDead.size(); i != e; ++i)
470 removeFromWorkList(NowDead[i]);
472 // Finally, since the node is now dead, remove it from the graph.
478 // If the root changed (e.g. it was a dead load, update the root).
479 DAG.setRoot(Dummy.getValue());
482 SDOperand DAGCombiner::visit(SDNode *N) {
483 switch(N->getOpcode()) {
485 case ISD::TokenFactor: return visitTokenFactor(N);
486 case ISD::ADD: return visitADD(N);
487 case ISD::SUB: return visitSUB(N);
488 case ISD::MUL: return visitMUL(N);
489 case ISD::SDIV: return visitSDIV(N);
490 case ISD::UDIV: return visitUDIV(N);
491 case ISD::SREM: return visitSREM(N);
492 case ISD::UREM: return visitUREM(N);
493 case ISD::MULHU: return visitMULHU(N);
494 case ISD::MULHS: return visitMULHS(N);
495 case ISD::AND: return visitAND(N);
496 case ISD::OR: return visitOR(N);
497 case ISD::XOR: return visitXOR(N);
498 case ISD::SHL: return visitSHL(N);
499 case ISD::SRA: return visitSRA(N);
500 case ISD::SRL: return visitSRL(N);
501 case ISD::CTLZ: return visitCTLZ(N);
502 case ISD::CTTZ: return visitCTTZ(N);
503 case ISD::CTPOP: return visitCTPOP(N);
504 case ISD::SELECT: return visitSELECT(N);
505 case ISD::SELECT_CC: return visitSELECT_CC(N);
506 case ISD::SETCC: return visitSETCC(N);
507 case ISD::SIGN_EXTEND: return visitSIGN_EXTEND(N);
508 case ISD::ZERO_EXTEND: return visitZERO_EXTEND(N);
509 case ISD::ANY_EXTEND: return visitANY_EXTEND(N);
510 case ISD::SIGN_EXTEND_INREG: return visitSIGN_EXTEND_INREG(N);
511 case ISD::TRUNCATE: return visitTRUNCATE(N);
512 case ISD::BIT_CONVERT: return visitBIT_CONVERT(N);
513 case ISD::VBIT_CONVERT: return visitVBIT_CONVERT(N);
514 case ISD::FADD: return visitFADD(N);
515 case ISD::FSUB: return visitFSUB(N);
516 case ISD::FMUL: return visitFMUL(N);
517 case ISD::FDIV: return visitFDIV(N);
518 case ISD::FREM: return visitFREM(N);
519 case ISD::FCOPYSIGN: return visitFCOPYSIGN(N);
520 case ISD::SINT_TO_FP: return visitSINT_TO_FP(N);
521 case ISD::UINT_TO_FP: return visitUINT_TO_FP(N);
522 case ISD::FP_TO_SINT: return visitFP_TO_SINT(N);
523 case ISD::FP_TO_UINT: return visitFP_TO_UINT(N);
524 case ISD::FP_ROUND: return visitFP_ROUND(N);
525 case ISD::FP_ROUND_INREG: return visitFP_ROUND_INREG(N);
526 case ISD::FP_EXTEND: return visitFP_EXTEND(N);
527 case ISD::FNEG: return visitFNEG(N);
528 case ISD::FABS: return visitFABS(N);
529 case ISD::BRCOND: return visitBRCOND(N);
530 case ISD::BR_CC: return visitBR_CC(N);
531 case ISD::LOAD: return visitLOAD(N);
532 case ISD::STORE: return visitSTORE(N);
533 case ISD::INSERT_VECTOR_ELT: return visitINSERT_VECTOR_ELT(N);
534 case ISD::VINSERT_VECTOR_ELT: return visitVINSERT_VECTOR_ELT(N);
535 case ISD::VBUILD_VECTOR: return visitVBUILD_VECTOR(N);
536 case ISD::VECTOR_SHUFFLE: return visitVECTOR_SHUFFLE(N);
537 case ISD::VVECTOR_SHUFFLE: return visitVVECTOR_SHUFFLE(N);
538 case ISD::VADD: return visitVBinOp(N, ISD::ADD , ISD::FADD);
539 case ISD::VSUB: return visitVBinOp(N, ISD::SUB , ISD::FSUB);
540 case ISD::VMUL: return visitVBinOp(N, ISD::MUL , ISD::FMUL);
541 case ISD::VSDIV: return visitVBinOp(N, ISD::SDIV, ISD::FDIV);
542 case ISD::VUDIV: return visitVBinOp(N, ISD::UDIV, ISD::UDIV);
543 case ISD::VAND: return visitVBinOp(N, ISD::AND , ISD::AND);
544 case ISD::VOR: return visitVBinOp(N, ISD::OR , ISD::OR);
545 case ISD::VXOR: return visitVBinOp(N, ISD::XOR , ISD::XOR);
550 /// getInputChainForNode - Given a node, return its input chain if it has one,
551 /// otherwise return a null sd operand.
552 static SDOperand getInputChainForNode(SDNode *N) {
553 if (unsigned NumOps = N->getNumOperands()) {
554 if (N->getOperand(0).getValueType() == MVT::Other)
555 return N->getOperand(0);
556 else if (N->getOperand(NumOps-1).getValueType() == MVT::Other)
557 return N->getOperand(NumOps-1);
558 for (unsigned i = 1; i < NumOps-1; ++i)
559 if (N->getOperand(i).getValueType() == MVT::Other)
560 return N->getOperand(i);
562 return SDOperand(0, 0);
565 SDOperand DAGCombiner::visitTokenFactor(SDNode *N) {
566 // If N has two operands, where one has an input chain equal to the other,
567 // the 'other' chain is redundant.
568 if (N->getNumOperands() == 2) {
569 if (getInputChainForNode(N->getOperand(0).Val) == N->getOperand(1))
570 return N->getOperand(0);
571 if (getInputChainForNode(N->getOperand(1).Val) == N->getOperand(0))
572 return N->getOperand(1);
576 SmallVector<SDNode *, 8> TFs; // List of token factors to visit.
577 SmallVector<SDOperand, 8> Ops; // Ops for replacing token factor.
578 bool Changed = false; // If we should replace this token factor.
580 // Start out with this token factor.
583 // Iterate through token factors. The TFs grows when new token factors are
585 for (unsigned i = 0; i < TFs.size(); ++i) {
588 // Check each of the operands.
589 for (unsigned i = 0, ie = TF->getNumOperands(); i != ie; ++i) {
590 SDOperand Op = TF->getOperand(i);
592 switch (Op.getOpcode()) {
593 case ISD::EntryToken:
594 // Entry tokens don't need to be added to the list. They are
599 case ISD::TokenFactor:
600 if ((CombinerAA || Op.hasOneUse()) &&
601 std::find(TFs.begin(), TFs.end(), Op.Val) == TFs.end()) {
602 // Queue up for processing.
603 TFs.push_back(Op.Val);
604 // Clean up in case the token factor is removed.
605 AddToWorkList(Op.Val);
612 // Only add if not there prior.
613 if (std::find(Ops.begin(), Ops.end(), Op) == Ops.end())
622 // If we've change things around then replace token factor.
624 if (Ops.size() == 0) {
625 // The entry token is the only possible outcome.
626 Result = DAG.getEntryNode();
628 // New and improved token factor.
629 Result = DAG.getNode(ISD::TokenFactor, MVT::Other, &Ops[0], Ops.size());
632 // Don't add users to work list.
633 return CombineTo(N, Result, false);
639 SDOperand DAGCombiner::visitADD(SDNode *N) {
640 SDOperand N0 = N->getOperand(0);
641 SDOperand N1 = N->getOperand(1);
642 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
643 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
644 MVT::ValueType VT = N0.getValueType();
646 // fold (add c1, c2) -> c1+c2
648 return DAG.getNode(ISD::ADD, VT, N0, N1);
649 // canonicalize constant to RHS
651 return DAG.getNode(ISD::ADD, VT, N1, N0);
652 // fold (add x, 0) -> x
653 if (N1C && N1C->isNullValue())
655 // fold ((c1-A)+c2) -> (c1+c2)-A
656 if (N1C && N0.getOpcode() == ISD::SUB)
657 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getOperand(0)))
658 return DAG.getNode(ISD::SUB, VT,
659 DAG.getConstant(N1C->getValue()+N0C->getValue(), VT),
662 SDOperand RADD = ReassociateOps(ISD::ADD, N0, N1);
665 // fold ((0-A) + B) -> B-A
666 if (N0.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N0.getOperand(0)) &&
667 cast<ConstantSDNode>(N0.getOperand(0))->isNullValue())
668 return DAG.getNode(ISD::SUB, VT, N1, N0.getOperand(1));
669 // fold (A + (0-B)) -> A-B
670 if (N1.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N1.getOperand(0)) &&
671 cast<ConstantSDNode>(N1.getOperand(0))->isNullValue())
672 return DAG.getNode(ISD::SUB, VT, N0, N1.getOperand(1));
673 // fold (A+(B-A)) -> B
674 if (N1.getOpcode() == ISD::SUB && N0 == N1.getOperand(1))
675 return N1.getOperand(0);
677 if (!MVT::isVector(VT) && SimplifyDemandedBits(SDOperand(N, 0)))
678 return SDOperand(N, 0);
680 // fold (a+b) -> (a|b) iff a and b share no bits.
681 if (MVT::isInteger(VT) && !MVT::isVector(VT)) {
682 uint64_t LHSZero, LHSOne;
683 uint64_t RHSZero, RHSOne;
684 uint64_t Mask = MVT::getIntVTBitMask(VT);
685 TLI.ComputeMaskedBits(N0, Mask, LHSZero, LHSOne);
687 TLI.ComputeMaskedBits(N1, Mask, RHSZero, RHSOne);
689 // If all possibly-set bits on the LHS are clear on the RHS, return an OR.
690 // If all possibly-set bits on the RHS are clear on the LHS, return an OR.
691 if ((RHSZero & (~LHSZero & Mask)) == (~LHSZero & Mask) ||
692 (LHSZero & (~RHSZero & Mask)) == (~RHSZero & Mask))
693 return DAG.getNode(ISD::OR, VT, N0, N1);
700 SDOperand DAGCombiner::visitSUB(SDNode *N) {
701 SDOperand N0 = N->getOperand(0);
702 SDOperand N1 = N->getOperand(1);
703 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val);
704 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
705 MVT::ValueType VT = N0.getValueType();
707 // fold (sub x, x) -> 0
709 return DAG.getConstant(0, N->getValueType(0));
710 // fold (sub c1, c2) -> c1-c2
712 return DAG.getNode(ISD::SUB, VT, N0, N1);
713 // fold (sub x, c) -> (add x, -c)
715 return DAG.getNode(ISD::ADD, VT, N0, DAG.getConstant(-N1C->getValue(), VT));
717 if (N0.getOpcode() == ISD::ADD && N0.getOperand(0) == N1)
718 return N0.getOperand(1);
720 if (N0.getOpcode() == ISD::ADD && N0.getOperand(1) == N1)
721 return N0.getOperand(0);
725 SDOperand DAGCombiner::visitMUL(SDNode *N) {
726 SDOperand N0 = N->getOperand(0);
727 SDOperand N1 = N->getOperand(1);
728 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
729 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
730 MVT::ValueType VT = N0.getValueType();
732 // fold (mul c1, c2) -> c1*c2
734 return DAG.getNode(ISD::MUL, VT, N0, N1);
735 // canonicalize constant to RHS
737 return DAG.getNode(ISD::MUL, VT, N1, N0);
738 // fold (mul x, 0) -> 0
739 if (N1C && N1C->isNullValue())
741 // fold (mul x, -1) -> 0-x
742 if (N1C && N1C->isAllOnesValue())
743 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), N0);
744 // fold (mul x, (1 << c)) -> x << c
745 if (N1C && isPowerOf2_64(N1C->getValue()))
746 return DAG.getNode(ISD::SHL, VT, N0,
747 DAG.getConstant(Log2_64(N1C->getValue()),
748 TLI.getShiftAmountTy()));
749 // fold (mul x, -(1 << c)) -> -(x << c) or (-x) << c
750 if (N1C && isPowerOf2_64(-N1C->getSignExtended())) {
751 // FIXME: If the input is something that is easily negated (e.g. a
752 // single-use add), we should put the negate there.
753 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT),
754 DAG.getNode(ISD::SHL, VT, N0,
755 DAG.getConstant(Log2_64(-N1C->getSignExtended()),
756 TLI.getShiftAmountTy())));
759 // (mul (shl X, c1), c2) -> (mul X, c2 << c1)
760 if (N1C && N0.getOpcode() == ISD::SHL &&
761 isa<ConstantSDNode>(N0.getOperand(1))) {
762 SDOperand C3 = DAG.getNode(ISD::SHL, VT, N1, N0.getOperand(1));
763 AddToWorkList(C3.Val);
764 return DAG.getNode(ISD::MUL, VT, N0.getOperand(0), C3);
767 // Change (mul (shl X, C), Y) -> (shl (mul X, Y), C) when the shift has one
770 SDOperand Sh(0,0), Y(0,0);
771 // Check for both (mul (shl X, C), Y) and (mul Y, (shl X, C)).
772 if (N0.getOpcode() == ISD::SHL && isa<ConstantSDNode>(N0.getOperand(1)) &&
773 N0.Val->hasOneUse()) {
775 } else if (N1.getOpcode() == ISD::SHL &&
776 isa<ConstantSDNode>(N1.getOperand(1)) && N1.Val->hasOneUse()) {
780 SDOperand Mul = DAG.getNode(ISD::MUL, VT, Sh.getOperand(0), Y);
781 return DAG.getNode(ISD::SHL, VT, Mul, Sh.getOperand(1));
784 // fold (mul (add x, c1), c2) -> (add (mul x, c2), c1*c2)
785 if (N1C && N0.getOpcode() == ISD::ADD && N0.Val->hasOneUse() &&
786 isa<ConstantSDNode>(N0.getOperand(1))) {
787 return DAG.getNode(ISD::ADD, VT,
788 DAG.getNode(ISD::MUL, VT, N0.getOperand(0), N1),
789 DAG.getNode(ISD::MUL, VT, N0.getOperand(1), N1));
793 SDOperand RMUL = ReassociateOps(ISD::MUL, N0, N1);
799 SDOperand DAGCombiner::visitSDIV(SDNode *N) {
800 SDOperand N0 = N->getOperand(0);
801 SDOperand N1 = N->getOperand(1);
802 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val);
803 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
804 MVT::ValueType VT = N->getValueType(0);
806 // fold (sdiv c1, c2) -> c1/c2
807 if (N0C && N1C && !N1C->isNullValue())
808 return DAG.getNode(ISD::SDIV, VT, N0, N1);
809 // fold (sdiv X, 1) -> X
810 if (N1C && N1C->getSignExtended() == 1LL)
812 // fold (sdiv X, -1) -> 0-X
813 if (N1C && N1C->isAllOnesValue())
814 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), N0);
815 // If we know the sign bits of both operands are zero, strength reduce to a
816 // udiv instead. Handles (X&15) /s 4 -> X&15 >> 2
817 uint64_t SignBit = 1ULL << (MVT::getSizeInBits(VT)-1);
818 if (TLI.MaskedValueIsZero(N1, SignBit) &&
819 TLI.MaskedValueIsZero(N0, SignBit))
820 return DAG.getNode(ISD::UDIV, N1.getValueType(), N0, N1);
821 // fold (sdiv X, pow2) -> simple ops after legalize
822 if (N1C && N1C->getValue() && !TLI.isIntDivCheap() &&
823 (isPowerOf2_64(N1C->getSignExtended()) ||
824 isPowerOf2_64(-N1C->getSignExtended()))) {
825 // If dividing by powers of two is cheap, then don't perform the following
827 if (TLI.isPow2DivCheap())
829 int64_t pow2 = N1C->getSignExtended();
830 int64_t abs2 = pow2 > 0 ? pow2 : -pow2;
831 unsigned lg2 = Log2_64(abs2);
832 // Splat the sign bit into the register
833 SDOperand SGN = DAG.getNode(ISD::SRA, VT, N0,
834 DAG.getConstant(MVT::getSizeInBits(VT)-1,
835 TLI.getShiftAmountTy()));
836 AddToWorkList(SGN.Val);
837 // Add (N0 < 0) ? abs2 - 1 : 0;
838 SDOperand SRL = DAG.getNode(ISD::SRL, VT, SGN,
839 DAG.getConstant(MVT::getSizeInBits(VT)-lg2,
840 TLI.getShiftAmountTy()));
841 SDOperand ADD = DAG.getNode(ISD::ADD, VT, N0, SRL);
842 AddToWorkList(SRL.Val);
843 AddToWorkList(ADD.Val); // Divide by pow2
844 SDOperand SRA = DAG.getNode(ISD::SRA, VT, ADD,
845 DAG.getConstant(lg2, TLI.getShiftAmountTy()));
846 // If we're dividing by a positive value, we're done. Otherwise, we must
847 // negate the result.
850 AddToWorkList(SRA.Val);
851 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), SRA);
853 // if integer divide is expensive and we satisfy the requirements, emit an
854 // alternate sequence.
855 if (N1C && (N1C->getSignExtended() < -1 || N1C->getSignExtended() > 1) &&
856 !TLI.isIntDivCheap()) {
857 SDOperand Op = BuildSDIV(N);
858 if (Op.Val) return Op;
863 SDOperand DAGCombiner::visitUDIV(SDNode *N) {
864 SDOperand N0 = N->getOperand(0);
865 SDOperand N1 = N->getOperand(1);
866 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val);
867 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
868 MVT::ValueType VT = N->getValueType(0);
870 // fold (udiv c1, c2) -> c1/c2
871 if (N0C && N1C && !N1C->isNullValue())
872 return DAG.getNode(ISD::UDIV, VT, N0, N1);
873 // fold (udiv x, (1 << c)) -> x >>u c
874 if (N1C && isPowerOf2_64(N1C->getValue()))
875 return DAG.getNode(ISD::SRL, VT, N0,
876 DAG.getConstant(Log2_64(N1C->getValue()),
877 TLI.getShiftAmountTy()));
878 // fold (udiv x, (shl c, y)) -> x >>u (log2(c)+y) iff c is power of 2
879 if (N1.getOpcode() == ISD::SHL) {
880 if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) {
881 if (isPowerOf2_64(SHC->getValue())) {
882 MVT::ValueType ADDVT = N1.getOperand(1).getValueType();
883 SDOperand Add = DAG.getNode(ISD::ADD, ADDVT, N1.getOperand(1),
884 DAG.getConstant(Log2_64(SHC->getValue()),
886 AddToWorkList(Add.Val);
887 return DAG.getNode(ISD::SRL, VT, N0, Add);
891 // fold (udiv x, c) -> alternate
892 if (N1C && N1C->getValue() && !TLI.isIntDivCheap()) {
893 SDOperand Op = BuildUDIV(N);
894 if (Op.Val) return Op;
899 SDOperand DAGCombiner::visitSREM(SDNode *N) {
900 SDOperand N0 = N->getOperand(0);
901 SDOperand N1 = N->getOperand(1);
902 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
903 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
904 MVT::ValueType VT = N->getValueType(0);
906 // fold (srem c1, c2) -> c1%c2
907 if (N0C && N1C && !N1C->isNullValue())
908 return DAG.getNode(ISD::SREM, VT, N0, N1);
909 // If we know the sign bits of both operands are zero, strength reduce to a
910 // urem instead. Handles (X & 0x0FFFFFFF) %s 16 -> X&15
911 uint64_t SignBit = 1ULL << (MVT::getSizeInBits(VT)-1);
912 if (TLI.MaskedValueIsZero(N1, SignBit) &&
913 TLI.MaskedValueIsZero(N0, SignBit))
914 return DAG.getNode(ISD::UREM, VT, N0, N1);
916 // Unconditionally lower X%C -> X-X/C*C. This allows the X/C logic to hack on
917 // the remainder operation.
918 if (N1C && !N1C->isNullValue()) {
919 SDOperand Div = DAG.getNode(ISD::SDIV, VT, N0, N1);
920 SDOperand Mul = DAG.getNode(ISD::MUL, VT, Div, N1);
921 SDOperand Sub = DAG.getNode(ISD::SUB, VT, N0, Mul);
922 AddToWorkList(Div.Val);
923 AddToWorkList(Mul.Val);
930 SDOperand DAGCombiner::visitUREM(SDNode *N) {
931 SDOperand N0 = N->getOperand(0);
932 SDOperand N1 = N->getOperand(1);
933 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
934 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
935 MVT::ValueType VT = N->getValueType(0);
937 // fold (urem c1, c2) -> c1%c2
938 if (N0C && N1C && !N1C->isNullValue())
939 return DAG.getNode(ISD::UREM, VT, N0, N1);
940 // fold (urem x, pow2) -> (and x, pow2-1)
941 if (N1C && !N1C->isNullValue() && isPowerOf2_64(N1C->getValue()))
942 return DAG.getNode(ISD::AND, VT, N0, DAG.getConstant(N1C->getValue()-1,VT));
943 // fold (urem x, (shl pow2, y)) -> (and x, (add (shl pow2, y), -1))
944 if (N1.getOpcode() == ISD::SHL) {
945 if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) {
946 if (isPowerOf2_64(SHC->getValue())) {
947 SDOperand Add = DAG.getNode(ISD::ADD, VT, N1,DAG.getConstant(~0ULL,VT));
948 AddToWorkList(Add.Val);
949 return DAG.getNode(ISD::AND, VT, N0, Add);
954 // Unconditionally lower X%C -> X-X/C*C. This allows the X/C logic to hack on
955 // the remainder operation.
956 if (N1C && !N1C->isNullValue()) {
957 SDOperand Div = DAG.getNode(ISD::UDIV, VT, N0, N1);
958 SDOperand Mul = DAG.getNode(ISD::MUL, VT, Div, N1);
959 SDOperand Sub = DAG.getNode(ISD::SUB, VT, N0, Mul);
960 AddToWorkList(Div.Val);
961 AddToWorkList(Mul.Val);
968 SDOperand DAGCombiner::visitMULHS(SDNode *N) {
969 SDOperand N0 = N->getOperand(0);
970 SDOperand N1 = N->getOperand(1);
971 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
973 // fold (mulhs x, 0) -> 0
974 if (N1C && N1C->isNullValue())
976 // fold (mulhs x, 1) -> (sra x, size(x)-1)
977 if (N1C && N1C->getValue() == 1)
978 return DAG.getNode(ISD::SRA, N0.getValueType(), N0,
979 DAG.getConstant(MVT::getSizeInBits(N0.getValueType())-1,
980 TLI.getShiftAmountTy()));
984 SDOperand DAGCombiner::visitMULHU(SDNode *N) {
985 SDOperand N0 = N->getOperand(0);
986 SDOperand N1 = N->getOperand(1);
987 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
989 // fold (mulhu x, 0) -> 0
990 if (N1C && N1C->isNullValue())
992 // fold (mulhu x, 1) -> 0
993 if (N1C && N1C->getValue() == 1)
994 return DAG.getConstant(0, N0.getValueType());
998 /// SimplifyBinOpWithSameOpcodeHands - If this is a binary operator with
999 /// two operands of the same opcode, try to simplify it.
1000 SDOperand DAGCombiner::SimplifyBinOpWithSameOpcodeHands(SDNode *N) {
1001 SDOperand N0 = N->getOperand(0), N1 = N->getOperand(1);
1002 MVT::ValueType VT = N0.getValueType();
1003 assert(N0.getOpcode() == N1.getOpcode() && "Bad input!");
1005 // For each of OP in AND/OR/XOR:
1006 // fold (OP (zext x), (zext y)) -> (zext (OP x, y))
1007 // fold (OP (sext x), (sext y)) -> (sext (OP x, y))
1008 // fold (OP (aext x), (aext y)) -> (aext (OP x, y))
1009 // fold (OP (trunc x), (trunc y)) -> (trunc (OP x, y))
1010 if ((N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND||
1011 N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::TRUNCATE) &&
1012 N0.getOperand(0).getValueType() == N1.getOperand(0).getValueType()) {
1013 SDOperand ORNode = DAG.getNode(N->getOpcode(),
1014 N0.getOperand(0).getValueType(),
1015 N0.getOperand(0), N1.getOperand(0));
1016 AddToWorkList(ORNode.Val);
1017 return DAG.getNode(N0.getOpcode(), VT, ORNode);
1020 // For each of OP in SHL/SRL/SRA/AND...
1021 // fold (and (OP x, z), (OP y, z)) -> (OP (and x, y), z)
1022 // fold (or (OP x, z), (OP y, z)) -> (OP (or x, y), z)
1023 // fold (xor (OP x, z), (OP y, z)) -> (OP (xor x, y), z)
1024 if ((N0.getOpcode() == ISD::SHL || N0.getOpcode() == ISD::SRL ||
1025 N0.getOpcode() == ISD::SRA || N0.getOpcode() == ISD::AND) &&
1026 N0.getOperand(1) == N1.getOperand(1)) {
1027 SDOperand ORNode = DAG.getNode(N->getOpcode(),
1028 N0.getOperand(0).getValueType(),
1029 N0.getOperand(0), N1.getOperand(0));
1030 AddToWorkList(ORNode.Val);
1031 return DAG.getNode(N0.getOpcode(), VT, ORNode, N0.getOperand(1));
1037 SDOperand DAGCombiner::visitAND(SDNode *N) {
1038 SDOperand N0 = N->getOperand(0);
1039 SDOperand N1 = N->getOperand(1);
1040 SDOperand LL, LR, RL, RR, CC0, CC1;
1041 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1042 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1043 MVT::ValueType VT = N1.getValueType();
1045 // fold (and c1, c2) -> c1&c2
1047 return DAG.getNode(ISD::AND, VT, N0, N1);
1048 // canonicalize constant to RHS
1050 return DAG.getNode(ISD::AND, VT, N1, N0);
1051 // fold (and x, -1) -> x
1052 if (N1C && N1C->isAllOnesValue())
1054 // if (and x, c) is known to be zero, return 0
1055 if (N1C && TLI.MaskedValueIsZero(SDOperand(N, 0), MVT::getIntVTBitMask(VT)))
1056 return DAG.getConstant(0, VT);
1058 SDOperand RAND = ReassociateOps(ISD::AND, N0, N1);
1061 // fold (and (or x, 0xFFFF), 0xFF) -> 0xFF
1062 if (N1C && N0.getOpcode() == ISD::OR)
1063 if (ConstantSDNode *ORI = dyn_cast<ConstantSDNode>(N0.getOperand(1)))
1064 if ((ORI->getValue() & N1C->getValue()) == N1C->getValue())
1066 // fold (and (any_ext V), c) -> (zero_ext V) if 'and' only clears top bits.
1067 if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) {
1068 unsigned InMask = MVT::getIntVTBitMask(N0.getOperand(0).getValueType());
1069 if (TLI.MaskedValueIsZero(N0.getOperand(0),
1070 ~N1C->getValue() & InMask)) {
1071 SDOperand Zext = DAG.getNode(ISD::ZERO_EXTEND, N0.getValueType(),
1074 // Replace uses of the AND with uses of the Zero extend node.
1077 // We actually want to replace all uses of the any_extend with the
1078 // zero_extend, to avoid duplicating things. This will later cause this
1079 // AND to be folded.
1080 CombineTo(N0.Val, Zext);
1081 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1084 // fold (and (setcc x), (setcc y)) -> (setcc (and x, y))
1085 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){
1086 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get();
1087 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get();
1089 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 &&
1090 MVT::isInteger(LL.getValueType())) {
1091 // fold (X == 0) & (Y == 0) -> (X|Y == 0)
1092 if (cast<ConstantSDNode>(LR)->getValue() == 0 && Op1 == ISD::SETEQ) {
1093 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL);
1094 AddToWorkList(ORNode.Val);
1095 return DAG.getSetCC(VT, ORNode, LR, Op1);
1097 // fold (X == -1) & (Y == -1) -> (X&Y == -1)
1098 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETEQ) {
1099 SDOperand ANDNode = DAG.getNode(ISD::AND, LR.getValueType(), LL, RL);
1100 AddToWorkList(ANDNode.Val);
1101 return DAG.getSetCC(VT, ANDNode, LR, Op1);
1103 // fold (X > -1) & (Y > -1) -> (X|Y > -1)
1104 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETGT) {
1105 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL);
1106 AddToWorkList(ORNode.Val);
1107 return DAG.getSetCC(VT, ORNode, LR, Op1);
1110 // canonicalize equivalent to ll == rl
1111 if (LL == RR && LR == RL) {
1112 Op1 = ISD::getSetCCSwappedOperands(Op1);
1115 if (LL == RL && LR == RR) {
1116 bool isInteger = MVT::isInteger(LL.getValueType());
1117 ISD::CondCode Result = ISD::getSetCCAndOperation(Op0, Op1, isInteger);
1118 if (Result != ISD::SETCC_INVALID)
1119 return DAG.getSetCC(N0.getValueType(), LL, LR, Result);
1123 // Simplify: and (op x...), (op y...) -> (op (and x, y))
1124 if (N0.getOpcode() == N1.getOpcode()) {
1125 SDOperand Tmp = SimplifyBinOpWithSameOpcodeHands(N);
1126 if (Tmp.Val) return Tmp;
1129 // fold (and (sign_extend_inreg x, i16 to i32), 1) -> (and x, 1)
1130 // fold (and (sra)) -> (and (srl)) when possible.
1131 if (!MVT::isVector(VT) &&
1132 SimplifyDemandedBits(SDOperand(N, 0)))
1133 return SDOperand(N, 0);
1134 // fold (zext_inreg (extload x)) -> (zextload x)
1135 if (ISD::isEXTLoad(N0.Val)) {
1136 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
1137 MVT::ValueType EVT = LN0->getLoadedVT();
1138 // If we zero all the possible extended bits, then we can turn this into
1139 // a zextload if we are running before legalize or the operation is legal.
1140 if (TLI.MaskedValueIsZero(N1, ~0ULL << MVT::getSizeInBits(EVT)) &&
1141 (!AfterLegalize || TLI.isLoadXLegal(ISD::ZEXTLOAD, EVT))) {
1142 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, LN0->getChain(),
1143 LN0->getBasePtr(), LN0->getSrcValue(),
1144 LN0->getSrcValueOffset(), EVT);
1146 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1));
1147 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1150 // fold (zext_inreg (sextload x)) -> (zextload x) iff load has one use
1151 if (ISD::isSEXTLoad(N0.Val) && N0.hasOneUse()) {
1152 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
1153 MVT::ValueType EVT = LN0->getLoadedVT();
1154 // If we zero all the possible extended bits, then we can turn this into
1155 // a zextload if we are running before legalize or the operation is legal.
1156 if (TLI.MaskedValueIsZero(N1, ~0ULL << MVT::getSizeInBits(EVT)) &&
1157 (!AfterLegalize || TLI.isLoadXLegal(ISD::ZEXTLOAD, EVT))) {
1158 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, LN0->getChain(),
1159 LN0->getBasePtr(), LN0->getSrcValue(),
1160 LN0->getSrcValueOffset(), EVT);
1162 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1));
1163 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1167 // fold (and (load x), 255) -> (zextload x, i8)
1168 // fold (and (extload x, i16), 255) -> (zextload x, i8)
1169 if (N1C && N0.getOpcode() == ISD::LOAD) {
1170 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
1171 if (LN0->getExtensionType() != ISD::SEXTLOAD &&
1173 MVT::ValueType EVT, LoadedVT;
1174 if (N1C->getValue() == 255)
1176 else if (N1C->getValue() == 65535)
1178 else if (N1C->getValue() == ~0U)
1183 LoadedVT = LN0->getLoadedVT();
1184 if (EVT != MVT::Other && LoadedVT > EVT &&
1185 (!AfterLegalize || TLI.isLoadXLegal(ISD::ZEXTLOAD, EVT))) {
1186 MVT::ValueType PtrType = N0.getOperand(1).getValueType();
1187 // For big endian targets, we need to add an offset to the pointer to
1188 // load the correct bytes. For little endian systems, we merely need to
1189 // read fewer bytes from the same pointer.
1191 (MVT::getSizeInBits(LoadedVT) - MVT::getSizeInBits(EVT)) / 8;
1192 SDOperand NewPtr = LN0->getBasePtr();
1193 if (!TLI.isLittleEndian())
1194 NewPtr = DAG.getNode(ISD::ADD, PtrType, NewPtr,
1195 DAG.getConstant(PtrOff, PtrType));
1196 AddToWorkList(NewPtr.Val);
1198 DAG.getExtLoad(ISD::ZEXTLOAD, VT, LN0->getChain(), NewPtr,
1199 LN0->getSrcValue(), LN0->getSrcValueOffset(), EVT);
1201 CombineTo(N0.Val, Load, Load.getValue(1));
1202 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1210 SDOperand DAGCombiner::visitOR(SDNode *N) {
1211 SDOperand N0 = N->getOperand(0);
1212 SDOperand N1 = N->getOperand(1);
1213 SDOperand LL, LR, RL, RR, CC0, CC1;
1214 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1215 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1216 MVT::ValueType VT = N1.getValueType();
1217 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
1219 // fold (or c1, c2) -> c1|c2
1221 return DAG.getNode(ISD::OR, VT, N0, N1);
1222 // canonicalize constant to RHS
1224 return DAG.getNode(ISD::OR, VT, N1, N0);
1225 // fold (or x, 0) -> x
1226 if (N1C && N1C->isNullValue())
1228 // fold (or x, -1) -> -1
1229 if (N1C && N1C->isAllOnesValue())
1231 // fold (or x, c) -> c iff (x & ~c) == 0
1233 TLI.MaskedValueIsZero(N0,~N1C->getValue() & (~0ULL>>(64-OpSizeInBits))))
1236 SDOperand ROR = ReassociateOps(ISD::OR, N0, N1);
1239 // Canonicalize (or (and X, c1), c2) -> (and (or X, c2), c1|c2)
1240 if (N1C && N0.getOpcode() == ISD::AND && N0.Val->hasOneUse() &&
1241 isa<ConstantSDNode>(N0.getOperand(1))) {
1242 ConstantSDNode *C1 = cast<ConstantSDNode>(N0.getOperand(1));
1243 return DAG.getNode(ISD::AND, VT, DAG.getNode(ISD::OR, VT, N0.getOperand(0),
1245 DAG.getConstant(N1C->getValue() | C1->getValue(), VT));
1247 // fold (or (setcc x), (setcc y)) -> (setcc (or x, y))
1248 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){
1249 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get();
1250 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get();
1252 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 &&
1253 MVT::isInteger(LL.getValueType())) {
1254 // fold (X != 0) | (Y != 0) -> (X|Y != 0)
1255 // fold (X < 0) | (Y < 0) -> (X|Y < 0)
1256 if (cast<ConstantSDNode>(LR)->getValue() == 0 &&
1257 (Op1 == ISD::SETNE || Op1 == ISD::SETLT)) {
1258 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL);
1259 AddToWorkList(ORNode.Val);
1260 return DAG.getSetCC(VT, ORNode, LR, Op1);
1262 // fold (X != -1) | (Y != -1) -> (X&Y != -1)
1263 // fold (X > -1) | (Y > -1) -> (X&Y > -1)
1264 if (cast<ConstantSDNode>(LR)->isAllOnesValue() &&
1265 (Op1 == ISD::SETNE || Op1 == ISD::SETGT)) {
1266 SDOperand ANDNode = DAG.getNode(ISD::AND, LR.getValueType(), LL, RL);
1267 AddToWorkList(ANDNode.Val);
1268 return DAG.getSetCC(VT, ANDNode, LR, Op1);
1271 // canonicalize equivalent to ll == rl
1272 if (LL == RR && LR == RL) {
1273 Op1 = ISD::getSetCCSwappedOperands(Op1);
1276 if (LL == RL && LR == RR) {
1277 bool isInteger = MVT::isInteger(LL.getValueType());
1278 ISD::CondCode Result = ISD::getSetCCOrOperation(Op0, Op1, isInteger);
1279 if (Result != ISD::SETCC_INVALID)
1280 return DAG.getSetCC(N0.getValueType(), LL, LR, Result);
1284 // Simplify: or (op x...), (op y...) -> (op (or x, y))
1285 if (N0.getOpcode() == N1.getOpcode()) {
1286 SDOperand Tmp = SimplifyBinOpWithSameOpcodeHands(N);
1287 if (Tmp.Val) return Tmp;
1290 // (X & C1) | (Y & C2) -> (X|Y) & C3 if possible.
1291 if (N0.getOpcode() == ISD::AND &&
1292 N1.getOpcode() == ISD::AND &&
1293 N0.getOperand(1).getOpcode() == ISD::Constant &&
1294 N1.getOperand(1).getOpcode() == ISD::Constant &&
1295 // Don't increase # computations.
1296 (N0.Val->hasOneUse() || N1.Val->hasOneUse())) {
1297 // We can only do this xform if we know that bits from X that are set in C2
1298 // but not in C1 are already zero. Likewise for Y.
1299 uint64_t LHSMask = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
1300 uint64_t RHSMask = cast<ConstantSDNode>(N1.getOperand(1))->getValue();
1302 if (TLI.MaskedValueIsZero(N0.getOperand(0), RHSMask&~LHSMask) &&
1303 TLI.MaskedValueIsZero(N1.getOperand(0), LHSMask&~RHSMask)) {
1304 SDOperand X =DAG.getNode(ISD::OR, VT, N0.getOperand(0), N1.getOperand(0));
1305 return DAG.getNode(ISD::AND, VT, X, DAG.getConstant(LHSMask|RHSMask, VT));
1310 // See if this is some rotate idiom.
1311 if (SDNode *Rot = MatchRotate(N0, N1))
1312 return SDOperand(Rot, 0);
1318 /// MatchRotateHalf - Match "(X shl/srl V1) & V2" where V2 may not be present.
1319 static bool MatchRotateHalf(SDOperand Op, SDOperand &Shift, SDOperand &Mask) {
1320 if (Op.getOpcode() == ISD::AND) {
1321 if (isa<ConstantSDNode>(Op.getOperand(1))) {
1322 Mask = Op.getOperand(1);
1323 Op = Op.getOperand(0);
1329 if (Op.getOpcode() == ISD::SRL || Op.getOpcode() == ISD::SHL) {
1337 // MatchRotate - Handle an 'or' of two operands. If this is one of the many
1338 // idioms for rotate, and if the target supports rotation instructions, generate
1340 SDNode *DAGCombiner::MatchRotate(SDOperand LHS, SDOperand RHS) {
1341 // Must be a legal type. Expanded an promoted things won't work with rotates.
1342 MVT::ValueType VT = LHS.getValueType();
1343 if (!TLI.isTypeLegal(VT)) return 0;
1345 // The target must have at least one rotate flavor.
1346 bool HasROTL = TLI.isOperationLegal(ISD::ROTL, VT);
1347 bool HasROTR = TLI.isOperationLegal(ISD::ROTR, VT);
1348 if (!HasROTL && !HasROTR) return 0;
1350 // Match "(X shl/srl V1) & V2" where V2 may not be present.
1351 SDOperand LHSShift; // The shift.
1352 SDOperand LHSMask; // AND value if any.
1353 if (!MatchRotateHalf(LHS, LHSShift, LHSMask))
1354 return 0; // Not part of a rotate.
1356 SDOperand RHSShift; // The shift.
1357 SDOperand RHSMask; // AND value if any.
1358 if (!MatchRotateHalf(RHS, RHSShift, RHSMask))
1359 return 0; // Not part of a rotate.
1361 if (LHSShift.getOperand(0) != RHSShift.getOperand(0))
1362 return 0; // Not shifting the same value.
1364 if (LHSShift.getOpcode() == RHSShift.getOpcode())
1365 return 0; // Shifts must disagree.
1367 // Canonicalize shl to left side in a shl/srl pair.
1368 if (RHSShift.getOpcode() == ISD::SHL) {
1369 std::swap(LHS, RHS);
1370 std::swap(LHSShift, RHSShift);
1371 std::swap(LHSMask , RHSMask );
1374 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
1376 // fold (or (shl x, C1), (srl x, C2)) -> (rotl x, C1)
1377 // fold (or (shl x, C1), (srl x, C2)) -> (rotr x, C2)
1378 if (LHSShift.getOperand(1).getOpcode() == ISD::Constant &&
1379 RHSShift.getOperand(1).getOpcode() == ISD::Constant) {
1380 uint64_t LShVal = cast<ConstantSDNode>(LHSShift.getOperand(1))->getValue();
1381 uint64_t RShVal = cast<ConstantSDNode>(RHSShift.getOperand(1))->getValue();
1382 if ((LShVal + RShVal) != OpSizeInBits)
1387 Rot = DAG.getNode(ISD::ROTL, VT, LHSShift.getOperand(0),
1388 LHSShift.getOperand(1));
1390 Rot = DAG.getNode(ISD::ROTR, VT, LHSShift.getOperand(0),
1391 RHSShift.getOperand(1));
1393 // If there is an AND of either shifted operand, apply it to the result.
1394 if (LHSMask.Val || RHSMask.Val) {
1395 uint64_t Mask = MVT::getIntVTBitMask(VT);
1398 uint64_t RHSBits = (1ULL << LShVal)-1;
1399 Mask &= cast<ConstantSDNode>(LHSMask)->getValue() | RHSBits;
1402 uint64_t LHSBits = ~((1ULL << (OpSizeInBits-RShVal))-1);
1403 Mask &= cast<ConstantSDNode>(RHSMask)->getValue() | LHSBits;
1406 Rot = DAG.getNode(ISD::AND, VT, Rot, DAG.getConstant(Mask, VT));
1412 // If there is a mask here, and we have a variable shift, we can't be sure
1413 // that we're masking out the right stuff.
1414 if (LHSMask.Val || RHSMask.Val)
1417 // fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotl x, y)
1418 // fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotr x, (sub 32, y))
1419 if (RHSShift.getOperand(1).getOpcode() == ISD::SUB &&
1420 LHSShift.getOperand(1) == RHSShift.getOperand(1).getOperand(1)) {
1421 if (ConstantSDNode *SUBC =
1422 dyn_cast<ConstantSDNode>(RHSShift.getOperand(1).getOperand(0))) {
1423 if (SUBC->getValue() == OpSizeInBits)
1425 return DAG.getNode(ISD::ROTL, VT, LHSShift.getOperand(0),
1426 LHSShift.getOperand(1)).Val;
1428 return DAG.getNode(ISD::ROTR, VT, LHSShift.getOperand(0),
1429 LHSShift.getOperand(1)).Val;
1433 // fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotr x, y)
1434 // fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotl x, (sub 32, y))
1435 if (LHSShift.getOperand(1).getOpcode() == ISD::SUB &&
1436 RHSShift.getOperand(1) == LHSShift.getOperand(1).getOperand(1)) {
1437 if (ConstantSDNode *SUBC =
1438 dyn_cast<ConstantSDNode>(LHSShift.getOperand(1).getOperand(0))) {
1439 if (SUBC->getValue() == OpSizeInBits)
1441 return DAG.getNode(ISD::ROTL, VT, LHSShift.getOperand(0),
1442 LHSShift.getOperand(1)).Val;
1444 return DAG.getNode(ISD::ROTR, VT, LHSShift.getOperand(0),
1445 RHSShift.getOperand(1)).Val;
1453 SDOperand DAGCombiner::visitXOR(SDNode *N) {
1454 SDOperand N0 = N->getOperand(0);
1455 SDOperand N1 = N->getOperand(1);
1456 SDOperand LHS, RHS, CC;
1457 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1458 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1459 MVT::ValueType VT = N0.getValueType();
1461 // fold (xor c1, c2) -> c1^c2
1463 return DAG.getNode(ISD::XOR, VT, N0, N1);
1464 // canonicalize constant to RHS
1466 return DAG.getNode(ISD::XOR, VT, N1, N0);
1467 // fold (xor x, 0) -> x
1468 if (N1C && N1C->isNullValue())
1471 SDOperand RXOR = ReassociateOps(ISD::XOR, N0, N1);
1474 // fold !(x cc y) -> (x !cc y)
1475 if (N1C && N1C->getValue() == 1 && isSetCCEquivalent(N0, LHS, RHS, CC)) {
1476 bool isInt = MVT::isInteger(LHS.getValueType());
1477 ISD::CondCode NotCC = ISD::getSetCCInverse(cast<CondCodeSDNode>(CC)->get(),
1479 if (N0.getOpcode() == ISD::SETCC)
1480 return DAG.getSetCC(VT, LHS, RHS, NotCC);
1481 if (N0.getOpcode() == ISD::SELECT_CC)
1482 return DAG.getSelectCC(LHS, RHS, N0.getOperand(2),N0.getOperand(3),NotCC);
1483 assert(0 && "Unhandled SetCC Equivalent!");
1486 // fold !(x or y) -> (!x and !y) iff x or y are setcc
1487 if (N1C && N1C->getValue() == 1 &&
1488 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) {
1489 SDOperand LHS = N0.getOperand(0), RHS = N0.getOperand(1);
1490 if (isOneUseSetCC(RHS) || isOneUseSetCC(LHS)) {
1491 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND;
1492 LHS = DAG.getNode(ISD::XOR, VT, LHS, N1); // RHS = ~LHS
1493 RHS = DAG.getNode(ISD::XOR, VT, RHS, N1); // RHS = ~RHS
1494 AddToWorkList(LHS.Val); AddToWorkList(RHS.Val);
1495 return DAG.getNode(NewOpcode, VT, LHS, RHS);
1498 // fold !(x or y) -> (!x and !y) iff x or y are constants
1499 if (N1C && N1C->isAllOnesValue() &&
1500 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) {
1501 SDOperand LHS = N0.getOperand(0), RHS = N0.getOperand(1);
1502 if (isa<ConstantSDNode>(RHS) || isa<ConstantSDNode>(LHS)) {
1503 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND;
1504 LHS = DAG.getNode(ISD::XOR, VT, LHS, N1); // RHS = ~LHS
1505 RHS = DAG.getNode(ISD::XOR, VT, RHS, N1); // RHS = ~RHS
1506 AddToWorkList(LHS.Val); AddToWorkList(RHS.Val);
1507 return DAG.getNode(NewOpcode, VT, LHS, RHS);
1510 // fold (xor (xor x, c1), c2) -> (xor x, c1^c2)
1511 if (N1C && N0.getOpcode() == ISD::XOR) {
1512 ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0));
1513 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
1515 return DAG.getNode(ISD::XOR, VT, N0.getOperand(1),
1516 DAG.getConstant(N1C->getValue()^N00C->getValue(), VT));
1518 return DAG.getNode(ISD::XOR, VT, N0.getOperand(0),
1519 DAG.getConstant(N1C->getValue()^N01C->getValue(), VT));
1521 // fold (xor x, x) -> 0
1523 if (!MVT::isVector(VT)) {
1524 return DAG.getConstant(0, VT);
1525 } else if (!AfterLegalize || TLI.isOperationLegal(ISD::BUILD_VECTOR, VT)) {
1526 // Produce a vector of zeros.
1527 SDOperand El = DAG.getConstant(0, MVT::getVectorBaseType(VT));
1528 std::vector<SDOperand> Ops(MVT::getVectorNumElements(VT), El);
1529 return DAG.getNode(ISD::BUILD_VECTOR, VT, &Ops[0], Ops.size());
1533 // Simplify: xor (op x...), (op y...) -> (op (xor x, y))
1534 if (N0.getOpcode() == N1.getOpcode()) {
1535 SDOperand Tmp = SimplifyBinOpWithSameOpcodeHands(N);
1536 if (Tmp.Val) return Tmp;
1539 // Simplify the expression using non-local knowledge.
1540 if (!MVT::isVector(VT) &&
1541 SimplifyDemandedBits(SDOperand(N, 0)))
1542 return SDOperand(N, 0);
1547 SDOperand DAGCombiner::visitSHL(SDNode *N) {
1548 SDOperand N0 = N->getOperand(0);
1549 SDOperand N1 = N->getOperand(1);
1550 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1551 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1552 MVT::ValueType VT = N0.getValueType();
1553 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
1555 // fold (shl c1, c2) -> c1<<c2
1557 return DAG.getNode(ISD::SHL, VT, N0, N1);
1558 // fold (shl 0, x) -> 0
1559 if (N0C && N0C->isNullValue())
1561 // fold (shl x, c >= size(x)) -> undef
1562 if (N1C && N1C->getValue() >= OpSizeInBits)
1563 return DAG.getNode(ISD::UNDEF, VT);
1564 // fold (shl x, 0) -> x
1565 if (N1C && N1C->isNullValue())
1567 // if (shl x, c) is known to be zero, return 0
1568 if (TLI.MaskedValueIsZero(SDOperand(N, 0), MVT::getIntVTBitMask(VT)))
1569 return DAG.getConstant(0, VT);
1570 if (SimplifyDemandedBits(SDOperand(N, 0)))
1571 return SDOperand(N, 0);
1572 // fold (shl (shl x, c1), c2) -> 0 or (shl x, c1+c2)
1573 if (N1C && N0.getOpcode() == ISD::SHL &&
1574 N0.getOperand(1).getOpcode() == ISD::Constant) {
1575 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
1576 uint64_t c2 = N1C->getValue();
1577 if (c1 + c2 > OpSizeInBits)
1578 return DAG.getConstant(0, VT);
1579 return DAG.getNode(ISD::SHL, VT, N0.getOperand(0),
1580 DAG.getConstant(c1 + c2, N1.getValueType()));
1582 // fold (shl (srl x, c1), c2) -> (shl (and x, -1 << c1), c2-c1) or
1583 // (srl (and x, -1 << c1), c1-c2)
1584 if (N1C && N0.getOpcode() == ISD::SRL &&
1585 N0.getOperand(1).getOpcode() == ISD::Constant) {
1586 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
1587 uint64_t c2 = N1C->getValue();
1588 SDOperand Mask = DAG.getNode(ISD::AND, VT, N0.getOperand(0),
1589 DAG.getConstant(~0ULL << c1, VT));
1591 return DAG.getNode(ISD::SHL, VT, Mask,
1592 DAG.getConstant(c2-c1, N1.getValueType()));
1594 return DAG.getNode(ISD::SRL, VT, Mask,
1595 DAG.getConstant(c1-c2, N1.getValueType()));
1597 // fold (shl (sra x, c1), c1) -> (and x, -1 << c1)
1598 if (N1C && N0.getOpcode() == ISD::SRA && N1 == N0.getOperand(1))
1599 return DAG.getNode(ISD::AND, VT, N0.getOperand(0),
1600 DAG.getConstant(~0ULL << N1C->getValue(), VT));
1601 // fold (shl (add x, c1), c2) -> (add (shl x, c2), c1<<c2)
1602 if (N1C && N0.getOpcode() == ISD::ADD && N0.Val->hasOneUse() &&
1603 isa<ConstantSDNode>(N0.getOperand(1))) {
1604 return DAG.getNode(ISD::ADD, VT,
1605 DAG.getNode(ISD::SHL, VT, N0.getOperand(0), N1),
1606 DAG.getNode(ISD::SHL, VT, N0.getOperand(1), N1));
1611 SDOperand DAGCombiner::visitSRA(SDNode *N) {
1612 SDOperand N0 = N->getOperand(0);
1613 SDOperand N1 = N->getOperand(1);
1614 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1615 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1616 MVT::ValueType VT = N0.getValueType();
1618 // fold (sra c1, c2) -> c1>>c2
1620 return DAG.getNode(ISD::SRA, VT, N0, N1);
1621 // fold (sra 0, x) -> 0
1622 if (N0C && N0C->isNullValue())
1624 // fold (sra -1, x) -> -1
1625 if (N0C && N0C->isAllOnesValue())
1627 // fold (sra x, c >= size(x)) -> undef
1628 if (N1C && N1C->getValue() >= MVT::getSizeInBits(VT))
1629 return DAG.getNode(ISD::UNDEF, VT);
1630 // fold (sra x, 0) -> x
1631 if (N1C && N1C->isNullValue())
1633 // fold (sra (shl x, c1), c1) -> sext_inreg for some c1 and target supports
1635 if (N1C && N0.getOpcode() == ISD::SHL && N1 == N0.getOperand(1)) {
1636 unsigned LowBits = MVT::getSizeInBits(VT) - (unsigned)N1C->getValue();
1639 default: EVT = MVT::Other; break;
1640 case 1: EVT = MVT::i1; break;
1641 case 8: EVT = MVT::i8; break;
1642 case 16: EVT = MVT::i16; break;
1643 case 32: EVT = MVT::i32; break;
1645 if (EVT > MVT::Other && TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, EVT))
1646 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0),
1647 DAG.getValueType(EVT));
1650 // fold (sra (sra x, c1), c2) -> (sra x, c1+c2)
1651 if (N1C && N0.getOpcode() == ISD::SRA) {
1652 if (ConstantSDNode *C1 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
1653 unsigned Sum = N1C->getValue() + C1->getValue();
1654 if (Sum >= MVT::getSizeInBits(VT)) Sum = MVT::getSizeInBits(VT)-1;
1655 return DAG.getNode(ISD::SRA, VT, N0.getOperand(0),
1656 DAG.getConstant(Sum, N1C->getValueType(0)));
1660 // Simplify, based on bits shifted out of the LHS.
1661 if (N1C && SimplifyDemandedBits(SDOperand(N, 0)))
1662 return SDOperand(N, 0);
1665 // If the sign bit is known to be zero, switch this to a SRL.
1666 if (TLI.MaskedValueIsZero(N0, MVT::getIntVTSignBit(VT)))
1667 return DAG.getNode(ISD::SRL, VT, N0, N1);
1671 SDOperand DAGCombiner::visitSRL(SDNode *N) {
1672 SDOperand N0 = N->getOperand(0);
1673 SDOperand N1 = N->getOperand(1);
1674 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1675 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1676 MVT::ValueType VT = N0.getValueType();
1677 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
1679 // fold (srl c1, c2) -> c1 >>u c2
1681 return DAG.getNode(ISD::SRL, VT, N0, N1);
1682 // fold (srl 0, x) -> 0
1683 if (N0C && N0C->isNullValue())
1685 // fold (srl x, c >= size(x)) -> undef
1686 if (N1C && N1C->getValue() >= OpSizeInBits)
1687 return DAG.getNode(ISD::UNDEF, VT);
1688 // fold (srl x, 0) -> x
1689 if (N1C && N1C->isNullValue())
1691 // if (srl x, c) is known to be zero, return 0
1692 if (N1C && TLI.MaskedValueIsZero(SDOperand(N, 0), ~0ULL >> (64-OpSizeInBits)))
1693 return DAG.getConstant(0, VT);
1694 // fold (srl (srl x, c1), c2) -> 0 or (srl x, c1+c2)
1695 if (N1C && N0.getOpcode() == ISD::SRL &&
1696 N0.getOperand(1).getOpcode() == ISD::Constant) {
1697 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
1698 uint64_t c2 = N1C->getValue();
1699 if (c1 + c2 > OpSizeInBits)
1700 return DAG.getConstant(0, VT);
1701 return DAG.getNode(ISD::SRL, VT, N0.getOperand(0),
1702 DAG.getConstant(c1 + c2, N1.getValueType()));
1705 // fold (srl (anyextend x), c) -> (anyextend (srl x, c))
1706 if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) {
1707 // Shifting in all undef bits?
1708 MVT::ValueType SmallVT = N0.getOperand(0).getValueType();
1709 if (N1C->getValue() >= MVT::getSizeInBits(SmallVT))
1710 return DAG.getNode(ISD::UNDEF, VT);
1712 SDOperand SmallShift = DAG.getNode(ISD::SRL, SmallVT, N0.getOperand(0), N1);
1713 AddToWorkList(SmallShift.Val);
1714 return DAG.getNode(ISD::ANY_EXTEND, VT, SmallShift);
1717 // fold (srl (sra X, Y), 31) -> (srl X, 31). This srl only looks at the sign
1718 // bit, which is unmodified by sra.
1719 if (N1C && N1C->getValue()+1 == MVT::getSizeInBits(VT)) {
1720 if (N0.getOpcode() == ISD::SRA)
1721 return DAG.getNode(ISD::SRL, VT, N0.getOperand(0), N1);
1724 // fold (srl (ctlz x), "5") -> x iff x has one bit set (the low bit).
1725 if (N1C && N0.getOpcode() == ISD::CTLZ &&
1726 N1C->getValue() == Log2_32(MVT::getSizeInBits(VT))) {
1727 uint64_t KnownZero, KnownOne, Mask = MVT::getIntVTBitMask(VT);
1728 TLI.ComputeMaskedBits(N0.getOperand(0), Mask, KnownZero, KnownOne);
1730 // If any of the input bits are KnownOne, then the input couldn't be all
1731 // zeros, thus the result of the srl will always be zero.
1732 if (KnownOne) return DAG.getConstant(0, VT);
1734 // If all of the bits input the to ctlz node are known to be zero, then
1735 // the result of the ctlz is "32" and the result of the shift is one.
1736 uint64_t UnknownBits = ~KnownZero & Mask;
1737 if (UnknownBits == 0) return DAG.getConstant(1, VT);
1739 // Otherwise, check to see if there is exactly one bit input to the ctlz.
1740 if ((UnknownBits & (UnknownBits-1)) == 0) {
1741 // Okay, we know that only that the single bit specified by UnknownBits
1742 // could be set on input to the CTLZ node. If this bit is set, the SRL
1743 // will return 0, if it is clear, it returns 1. Change the CTLZ/SRL pair
1744 // to an SRL,XOR pair, which is likely to simplify more.
1745 unsigned ShAmt = CountTrailingZeros_64(UnknownBits);
1746 SDOperand Op = N0.getOperand(0);
1748 Op = DAG.getNode(ISD::SRL, VT, Op,
1749 DAG.getConstant(ShAmt, TLI.getShiftAmountTy()));
1750 AddToWorkList(Op.Val);
1752 return DAG.getNode(ISD::XOR, VT, Op, DAG.getConstant(1, VT));
1759 SDOperand DAGCombiner::visitCTLZ(SDNode *N) {
1760 SDOperand N0 = N->getOperand(0);
1761 MVT::ValueType VT = N->getValueType(0);
1763 // fold (ctlz c1) -> c2
1764 if (isa<ConstantSDNode>(N0))
1765 return DAG.getNode(ISD::CTLZ, VT, N0);
1769 SDOperand DAGCombiner::visitCTTZ(SDNode *N) {
1770 SDOperand N0 = N->getOperand(0);
1771 MVT::ValueType VT = N->getValueType(0);
1773 // fold (cttz c1) -> c2
1774 if (isa<ConstantSDNode>(N0))
1775 return DAG.getNode(ISD::CTTZ, VT, N0);
1779 SDOperand DAGCombiner::visitCTPOP(SDNode *N) {
1780 SDOperand N0 = N->getOperand(0);
1781 MVT::ValueType VT = N->getValueType(0);
1783 // fold (ctpop c1) -> c2
1784 if (isa<ConstantSDNode>(N0))
1785 return DAG.getNode(ISD::CTPOP, VT, N0);
1789 SDOperand DAGCombiner::visitSELECT(SDNode *N) {
1790 SDOperand N0 = N->getOperand(0);
1791 SDOperand N1 = N->getOperand(1);
1792 SDOperand N2 = N->getOperand(2);
1793 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1794 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1795 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2);
1796 MVT::ValueType VT = N->getValueType(0);
1798 // fold select C, X, X -> X
1801 // fold select true, X, Y -> X
1802 if (N0C && !N0C->isNullValue())
1804 // fold select false, X, Y -> Y
1805 if (N0C && N0C->isNullValue())
1807 // fold select C, 1, X -> C | X
1808 if (MVT::i1 == VT && N1C && N1C->getValue() == 1)
1809 return DAG.getNode(ISD::OR, VT, N0, N2);
1810 // fold select C, 0, X -> ~C & X
1811 // FIXME: this should check for C type == X type, not i1?
1812 if (MVT::i1 == VT && N1C && N1C->isNullValue()) {
1813 SDOperand XORNode = DAG.getNode(ISD::XOR, VT, N0, DAG.getConstant(1, VT));
1814 AddToWorkList(XORNode.Val);
1815 return DAG.getNode(ISD::AND, VT, XORNode, N2);
1817 // fold select C, X, 1 -> ~C | X
1818 if (MVT::i1 == VT && N2C && N2C->getValue() == 1) {
1819 SDOperand XORNode = DAG.getNode(ISD::XOR, VT, N0, DAG.getConstant(1, VT));
1820 AddToWorkList(XORNode.Val);
1821 return DAG.getNode(ISD::OR, VT, XORNode, N1);
1823 // fold select C, X, 0 -> C & X
1824 // FIXME: this should check for C type == X type, not i1?
1825 if (MVT::i1 == VT && N2C && N2C->isNullValue())
1826 return DAG.getNode(ISD::AND, VT, N0, N1);
1827 // fold X ? X : Y --> X ? 1 : Y --> X | Y
1828 if (MVT::i1 == VT && N0 == N1)
1829 return DAG.getNode(ISD::OR, VT, N0, N2);
1830 // fold X ? Y : X --> X ? Y : 0 --> X & Y
1831 if (MVT::i1 == VT && N0 == N2)
1832 return DAG.getNode(ISD::AND, VT, N0, N1);
1834 // If we can fold this based on the true/false value, do so.
1835 if (SimplifySelectOps(N, N1, N2))
1836 return SDOperand(N, 0); // Don't revisit N.
1838 // fold selects based on a setcc into other things, such as min/max/abs
1839 if (N0.getOpcode() == ISD::SETCC)
1841 // Check against MVT::Other for SELECT_CC, which is a workaround for targets
1842 // having to say they don't support SELECT_CC on every type the DAG knows
1843 // about, since there is no way to mark an opcode illegal at all value types
1844 if (TLI.isOperationLegal(ISD::SELECT_CC, MVT::Other))
1845 return DAG.getNode(ISD::SELECT_CC, VT, N0.getOperand(0), N0.getOperand(1),
1846 N1, N2, N0.getOperand(2));
1848 return SimplifySelect(N0, N1, N2);
1852 SDOperand DAGCombiner::visitSELECT_CC(SDNode *N) {
1853 SDOperand N0 = N->getOperand(0);
1854 SDOperand N1 = N->getOperand(1);
1855 SDOperand N2 = N->getOperand(2);
1856 SDOperand N3 = N->getOperand(3);
1857 SDOperand N4 = N->getOperand(4);
1858 ISD::CondCode CC = cast<CondCodeSDNode>(N4)->get();
1860 // fold select_cc lhs, rhs, x, x, cc -> x
1864 // Determine if the condition we're dealing with is constant
1865 SDOperand SCC = SimplifySetCC(TLI.getSetCCResultTy(), N0, N1, CC, false);
1866 if (SCC.Val) AddToWorkList(SCC.Val);
1868 if (ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.Val)) {
1869 if (SCCC->getValue())
1870 return N2; // cond always true -> true val
1872 return N3; // cond always false -> false val
1875 // Fold to a simpler select_cc
1876 if (SCC.Val && SCC.getOpcode() == ISD::SETCC)
1877 return DAG.getNode(ISD::SELECT_CC, N2.getValueType(),
1878 SCC.getOperand(0), SCC.getOperand(1), N2, N3,
1881 // If we can fold this based on the true/false value, do so.
1882 if (SimplifySelectOps(N, N2, N3))
1883 return SDOperand(N, 0); // Don't revisit N.
1885 // fold select_cc into other things, such as min/max/abs
1886 return SimplifySelectCC(N0, N1, N2, N3, CC);
1889 SDOperand DAGCombiner::visitSETCC(SDNode *N) {
1890 return SimplifySetCC(N->getValueType(0), N->getOperand(0), N->getOperand(1),
1891 cast<CondCodeSDNode>(N->getOperand(2))->get());
1894 SDOperand DAGCombiner::visitSIGN_EXTEND(SDNode *N) {
1895 SDOperand N0 = N->getOperand(0);
1896 MVT::ValueType VT = N->getValueType(0);
1898 // fold (sext c1) -> c1
1899 if (isa<ConstantSDNode>(N0))
1900 return DAG.getNode(ISD::SIGN_EXTEND, VT, N0);
1902 // fold (sext (sext x)) -> (sext x)
1903 // fold (sext (aext x)) -> (sext x)
1904 if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND)
1905 return DAG.getNode(ISD::SIGN_EXTEND, VT, N0.getOperand(0));
1907 // fold (sext (truncate x)) -> (sextinreg x).
1908 if (N0.getOpcode() == ISD::TRUNCATE &&
1909 (!AfterLegalize || TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG,
1910 N0.getValueType()))) {
1911 SDOperand Op = N0.getOperand(0);
1912 if (Op.getValueType() < VT) {
1913 Op = DAG.getNode(ISD::ANY_EXTEND, VT, Op);
1914 } else if (Op.getValueType() > VT) {
1915 Op = DAG.getNode(ISD::TRUNCATE, VT, Op);
1917 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, Op,
1918 DAG.getValueType(N0.getValueType()));
1921 // fold (sext (load x)) -> (sext (truncate (sextload x)))
1922 if (ISD::isNON_EXTLoad(N0.Val) && N0.hasOneUse() &&
1923 (!AfterLegalize||TLI.isLoadXLegal(ISD::SEXTLOAD, N0.getValueType()))){
1924 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
1925 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, LN0->getChain(),
1926 LN0->getBasePtr(), LN0->getSrcValue(),
1927 LN0->getSrcValueOffset(),
1929 CombineTo(N, ExtLoad);
1930 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
1931 ExtLoad.getValue(1));
1932 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1935 // fold (sext (sextload x)) -> (sext (truncate (sextload x)))
1936 // fold (sext ( extload x)) -> (sext (truncate (sextload x)))
1937 if ((ISD::isSEXTLoad(N0.Val) || ISD::isEXTLoad(N0.Val)) && N0.hasOneUse()) {
1938 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
1939 MVT::ValueType EVT = LN0->getLoadedVT();
1940 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, LN0->getChain(),
1941 LN0->getBasePtr(), LN0->getSrcValue(),
1942 LN0->getSrcValueOffset(), EVT);
1943 CombineTo(N, ExtLoad);
1944 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
1945 ExtLoad.getValue(1));
1946 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1952 SDOperand DAGCombiner::visitZERO_EXTEND(SDNode *N) {
1953 SDOperand N0 = N->getOperand(0);
1954 MVT::ValueType VT = N->getValueType(0);
1956 // fold (zext c1) -> c1
1957 if (isa<ConstantSDNode>(N0))
1958 return DAG.getNode(ISD::ZERO_EXTEND, VT, N0);
1959 // fold (zext (zext x)) -> (zext x)
1960 // fold (zext (aext x)) -> (zext x)
1961 if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND)
1962 return DAG.getNode(ISD::ZERO_EXTEND, VT, N0.getOperand(0));
1964 // fold (zext (truncate x)) -> (and x, mask)
1965 if (N0.getOpcode() == ISD::TRUNCATE &&
1966 (!AfterLegalize || TLI.isOperationLegal(ISD::AND, VT))) {
1967 SDOperand Op = N0.getOperand(0);
1968 if (Op.getValueType() < VT) {
1969 Op = DAG.getNode(ISD::ANY_EXTEND, VT, Op);
1970 } else if (Op.getValueType() > VT) {
1971 Op = DAG.getNode(ISD::TRUNCATE, VT, Op);
1973 return DAG.getZeroExtendInReg(Op, N0.getValueType());
1976 // fold (zext (and (trunc x), cst)) -> (and x, cst).
1977 if (N0.getOpcode() == ISD::AND &&
1978 N0.getOperand(0).getOpcode() == ISD::TRUNCATE &&
1979 N0.getOperand(1).getOpcode() == ISD::Constant) {
1980 SDOperand X = N0.getOperand(0).getOperand(0);
1981 if (X.getValueType() < VT) {
1982 X = DAG.getNode(ISD::ANY_EXTEND, VT, X);
1983 } else if (X.getValueType() > VT) {
1984 X = DAG.getNode(ISD::TRUNCATE, VT, X);
1986 uint64_t Mask = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
1987 return DAG.getNode(ISD::AND, VT, X, DAG.getConstant(Mask, VT));
1990 // fold (zext (load x)) -> (zext (truncate (zextload x)))
1991 if (ISD::isNON_EXTLoad(N0.Val) && N0.hasOneUse() &&
1992 (!AfterLegalize||TLI.isLoadXLegal(ISD::ZEXTLOAD, N0.getValueType()))) {
1993 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
1994 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, LN0->getChain(),
1995 LN0->getBasePtr(), LN0->getSrcValue(),
1996 LN0->getSrcValueOffset(),
1998 CombineTo(N, ExtLoad);
1999 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
2000 ExtLoad.getValue(1));
2001 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
2004 // fold (zext (zextload x)) -> (zext (truncate (zextload x)))
2005 // fold (zext ( extload x)) -> (zext (truncate (zextload x)))
2006 if ((ISD::isZEXTLoad(N0.Val) || ISD::isEXTLoad(N0.Val)) && N0.hasOneUse()) {
2007 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
2008 MVT::ValueType EVT = LN0->getLoadedVT();
2009 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, LN0->getChain(),
2010 LN0->getBasePtr(), LN0->getSrcValue(),
2011 LN0->getSrcValueOffset(), EVT);
2012 CombineTo(N, ExtLoad);
2013 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
2014 ExtLoad.getValue(1));
2015 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
2020 SDOperand DAGCombiner::visitANY_EXTEND(SDNode *N) {
2021 SDOperand N0 = N->getOperand(0);
2022 MVT::ValueType VT = N->getValueType(0);
2024 // fold (aext c1) -> c1
2025 if (isa<ConstantSDNode>(N0))
2026 return DAG.getNode(ISD::ANY_EXTEND, VT, N0);
2027 // fold (aext (aext x)) -> (aext x)
2028 // fold (aext (zext x)) -> (zext x)
2029 // fold (aext (sext x)) -> (sext x)
2030 if (N0.getOpcode() == ISD::ANY_EXTEND ||
2031 N0.getOpcode() == ISD::ZERO_EXTEND ||
2032 N0.getOpcode() == ISD::SIGN_EXTEND)
2033 return DAG.getNode(N0.getOpcode(), VT, N0.getOperand(0));
2035 // fold (aext (truncate x))
2036 if (N0.getOpcode() == ISD::TRUNCATE) {
2037 SDOperand TruncOp = N0.getOperand(0);
2038 if (TruncOp.getValueType() == VT)
2039 return TruncOp; // x iff x size == zext size.
2040 if (TruncOp.getValueType() > VT)
2041 return DAG.getNode(ISD::TRUNCATE, VT, TruncOp);
2042 return DAG.getNode(ISD::ANY_EXTEND, VT, TruncOp);
2045 // fold (aext (and (trunc x), cst)) -> (and x, cst).
2046 if (N0.getOpcode() == ISD::AND &&
2047 N0.getOperand(0).getOpcode() == ISD::TRUNCATE &&
2048 N0.getOperand(1).getOpcode() == ISD::Constant) {
2049 SDOperand X = N0.getOperand(0).getOperand(0);
2050 if (X.getValueType() < VT) {
2051 X = DAG.getNode(ISD::ANY_EXTEND, VT, X);
2052 } else if (X.getValueType() > VT) {
2053 X = DAG.getNode(ISD::TRUNCATE, VT, X);
2055 uint64_t Mask = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
2056 return DAG.getNode(ISD::AND, VT, X, DAG.getConstant(Mask, VT));
2059 // fold (aext (load x)) -> (aext (truncate (extload x)))
2060 if (ISD::isNON_EXTLoad(N0.Val) && N0.hasOneUse() &&
2061 (!AfterLegalize||TLI.isLoadXLegal(ISD::EXTLOAD, N0.getValueType()))) {
2062 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
2063 SDOperand ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, VT, LN0->getChain(),
2064 LN0->getBasePtr(), LN0->getSrcValue(),
2065 LN0->getSrcValueOffset(),
2067 CombineTo(N, ExtLoad);
2068 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
2069 ExtLoad.getValue(1));
2070 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
2073 // fold (aext (zextload x)) -> (aext (truncate (zextload x)))
2074 // fold (aext (sextload x)) -> (aext (truncate (sextload x)))
2075 // fold (aext ( extload x)) -> (aext (truncate (extload x)))
2076 if (N0.getOpcode() == ISD::LOAD && !ISD::isNON_EXTLoad(N0.Val) &&
2078 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
2079 MVT::ValueType EVT = LN0->getLoadedVT();
2080 SDOperand ExtLoad = DAG.getExtLoad(LN0->getExtensionType(), VT,
2081 LN0->getChain(), LN0->getBasePtr(),
2083 LN0->getSrcValueOffset(), EVT);
2084 CombineTo(N, ExtLoad);
2085 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
2086 ExtLoad.getValue(1));
2087 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
2093 SDOperand DAGCombiner::visitSIGN_EXTEND_INREG(SDNode *N) {
2094 SDOperand N0 = N->getOperand(0);
2095 SDOperand N1 = N->getOperand(1);
2096 MVT::ValueType VT = N->getValueType(0);
2097 MVT::ValueType EVT = cast<VTSDNode>(N1)->getVT();
2098 unsigned EVTBits = MVT::getSizeInBits(EVT);
2100 // fold (sext_in_reg c1) -> c1
2101 if (isa<ConstantSDNode>(N0) || N0.getOpcode() == ISD::UNDEF)
2102 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0, N1);
2104 // If the input is already sign extended, just drop the extension.
2105 if (TLI.ComputeNumSignBits(N0) >= MVT::getSizeInBits(VT)-EVTBits+1)
2108 // fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt2
2109 if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
2110 EVT < cast<VTSDNode>(N0.getOperand(1))->getVT()) {
2111 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0), N1);
2114 // fold (sext_in_reg x) -> (zext_in_reg x) if the sign bit is zero
2115 if (TLI.MaskedValueIsZero(N0, 1ULL << (EVTBits-1)))
2116 return DAG.getZeroExtendInReg(N0, EVT);
2118 // fold (sext_in_reg (srl X, 24), i8) -> sra X, 24
2119 // fold (sext_in_reg (srl X, 23), i8) -> sra X, 23 iff possible.
2120 // We already fold "(sext_in_reg (srl X, 25), i8) -> srl X, 25" above.
2121 if (N0.getOpcode() == ISD::SRL) {
2122 if (ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(N0.getOperand(1)))
2123 if (ShAmt->getValue()+EVTBits <= MVT::getSizeInBits(VT)) {
2124 // We can turn this into an SRA iff the input to the SRL is already sign
2126 unsigned InSignBits = TLI.ComputeNumSignBits(N0.getOperand(0));
2127 if (MVT::getSizeInBits(VT)-(ShAmt->getValue()+EVTBits) < InSignBits)
2128 return DAG.getNode(ISD::SRA, VT, N0.getOperand(0), N0.getOperand(1));
2132 // fold (sext_inreg (extload x)) -> (sextload x)
2133 if (ISD::isEXTLoad(N0.Val) &&
2134 EVT == cast<LoadSDNode>(N0)->getLoadedVT() &&
2135 (!AfterLegalize || TLI.isLoadXLegal(ISD::SEXTLOAD, EVT))) {
2136 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
2137 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, LN0->getChain(),
2138 LN0->getBasePtr(), LN0->getSrcValue(),
2139 LN0->getSrcValueOffset(), EVT);
2140 CombineTo(N, ExtLoad);
2141 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1));
2142 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
2144 // fold (sext_inreg (zextload x)) -> (sextload x) iff load has one use
2145 if (ISD::isZEXTLoad(N0.Val) && N0.hasOneUse() &&
2146 EVT == cast<LoadSDNode>(N0)->getLoadedVT() &&
2147 (!AfterLegalize || TLI.isLoadXLegal(ISD::SEXTLOAD, EVT))) {
2148 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
2149 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, LN0->getChain(),
2150 LN0->getBasePtr(), LN0->getSrcValue(),
2151 LN0->getSrcValueOffset(), EVT);
2152 CombineTo(N, ExtLoad);
2153 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1));
2154 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
2159 SDOperand DAGCombiner::visitTRUNCATE(SDNode *N) {
2160 SDOperand N0 = N->getOperand(0);
2161 MVT::ValueType VT = N->getValueType(0);
2164 if (N0.getValueType() == N->getValueType(0))
2166 // fold (truncate c1) -> c1
2167 if (isa<ConstantSDNode>(N0))
2168 return DAG.getNode(ISD::TRUNCATE, VT, N0);
2169 // fold (truncate (truncate x)) -> (truncate x)
2170 if (N0.getOpcode() == ISD::TRUNCATE)
2171 return DAG.getNode(ISD::TRUNCATE, VT, N0.getOperand(0));
2172 // fold (truncate (ext x)) -> (ext x) or (truncate x) or x
2173 if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::SIGN_EXTEND||
2174 N0.getOpcode() == ISD::ANY_EXTEND) {
2175 if (N0.getValueType() < VT)
2176 // if the source is smaller than the dest, we still need an extend
2177 return DAG.getNode(N0.getOpcode(), VT, N0.getOperand(0));
2178 else if (N0.getValueType() > VT)
2179 // if the source is larger than the dest, than we just need the truncate
2180 return DAG.getNode(ISD::TRUNCATE, VT, N0.getOperand(0));
2182 // if the source and dest are the same type, we can drop both the extend
2184 return N0.getOperand(0);
2186 // fold (truncate (load x)) -> (smaller load x)
2187 if (ISD::isNON_EXTLoad(N0.Val) && N0.hasOneUse()) {
2188 assert(MVT::getSizeInBits(N0.getValueType()) > MVT::getSizeInBits(VT) &&
2189 "Cannot truncate to larger type!");
2190 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
2191 MVT::ValueType PtrType = N0.getOperand(1).getValueType();
2192 // For big endian targets, we need to add an offset to the pointer to load
2193 // the correct bytes. For little endian systems, we merely need to read
2194 // fewer bytes from the same pointer.
2196 (MVT::getSizeInBits(N0.getValueType()) - MVT::getSizeInBits(VT)) / 8;
2197 SDOperand NewPtr = TLI.isLittleEndian() ? LN0->getBasePtr() :
2198 DAG.getNode(ISD::ADD, PtrType, LN0->getBasePtr(),
2199 DAG.getConstant(PtrOff, PtrType));
2200 AddToWorkList(NewPtr.Val);
2201 SDOperand Load = DAG.getLoad(VT, LN0->getChain(), NewPtr,
2202 LN0->getSrcValue(), LN0->getSrcValueOffset());
2204 CombineTo(N0.Val, Load, Load.getValue(1));
2205 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
2210 SDOperand DAGCombiner::visitBIT_CONVERT(SDNode *N) {
2211 SDOperand N0 = N->getOperand(0);
2212 MVT::ValueType VT = N->getValueType(0);
2214 // If the input is a constant, let getNode() fold it.
2215 if (isa<ConstantSDNode>(N0) || isa<ConstantFPSDNode>(N0)) {
2216 SDOperand Res = DAG.getNode(ISD::BIT_CONVERT, VT, N0);
2217 if (Res.Val != N) return Res;
2220 if (N0.getOpcode() == ISD::BIT_CONVERT) // conv(conv(x,t1),t2) -> conv(x,t2)
2221 return DAG.getNode(ISD::BIT_CONVERT, VT, N0.getOperand(0));
2223 // fold (conv (load x)) -> (load (conv*)x)
2224 // FIXME: These xforms need to know that the resultant load doesn't need a
2225 // higher alignment than the original!
2226 if (0 && ISD::isNON_EXTLoad(N0.Val) && N0.hasOneUse()) {
2227 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
2228 SDOperand Load = DAG.getLoad(VT, LN0->getChain(), LN0->getBasePtr(),
2229 LN0->getSrcValue(), LN0->getSrcValueOffset());
2231 CombineTo(N0.Val, DAG.getNode(ISD::BIT_CONVERT, N0.getValueType(), Load),
2239 SDOperand DAGCombiner::visitVBIT_CONVERT(SDNode *N) {
2240 SDOperand N0 = N->getOperand(0);
2241 MVT::ValueType VT = N->getValueType(0);
2243 // If the input is a VBUILD_VECTOR with all constant elements, fold this now.
2244 // First check to see if this is all constant.
2245 if (N0.getOpcode() == ISD::VBUILD_VECTOR && N0.Val->hasOneUse() &&
2246 VT == MVT::Vector) {
2247 bool isSimple = true;
2248 for (unsigned i = 0, e = N0.getNumOperands()-2; i != e; ++i)
2249 if (N0.getOperand(i).getOpcode() != ISD::UNDEF &&
2250 N0.getOperand(i).getOpcode() != ISD::Constant &&
2251 N0.getOperand(i).getOpcode() != ISD::ConstantFP) {
2256 MVT::ValueType DestEltVT = cast<VTSDNode>(N->getOperand(2))->getVT();
2257 if (isSimple && !MVT::isVector(DestEltVT)) {
2258 return ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(N0.Val, DestEltVT);
2265 /// ConstantFoldVBIT_CONVERTofVBUILD_VECTOR - We know that BV is a vbuild_vector
2266 /// node with Constant, ConstantFP or Undef operands. DstEltVT indicates the
2267 /// destination element value type.
2268 SDOperand DAGCombiner::
2269 ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(SDNode *BV, MVT::ValueType DstEltVT) {
2270 MVT::ValueType SrcEltVT = BV->getOperand(0).getValueType();
2272 // If this is already the right type, we're done.
2273 if (SrcEltVT == DstEltVT) return SDOperand(BV, 0);
2275 unsigned SrcBitSize = MVT::getSizeInBits(SrcEltVT);
2276 unsigned DstBitSize = MVT::getSizeInBits(DstEltVT);
2278 // If this is a conversion of N elements of one type to N elements of another
2279 // type, convert each element. This handles FP<->INT cases.
2280 if (SrcBitSize == DstBitSize) {
2281 SmallVector<SDOperand, 8> Ops;
2282 for (unsigned i = 0, e = BV->getNumOperands()-2; i != e; ++i) {
2283 Ops.push_back(DAG.getNode(ISD::BIT_CONVERT, DstEltVT, BV->getOperand(i)));
2284 AddToWorkList(Ops.back().Val);
2286 Ops.push_back(*(BV->op_end()-2)); // Add num elements.
2287 Ops.push_back(DAG.getValueType(DstEltVT));
2288 return DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, &Ops[0], Ops.size());
2291 // Otherwise, we're growing or shrinking the elements. To avoid having to
2292 // handle annoying details of growing/shrinking FP values, we convert them to
2294 if (MVT::isFloatingPoint(SrcEltVT)) {
2295 // Convert the input float vector to a int vector where the elements are the
2297 assert((SrcEltVT == MVT::f32 || SrcEltVT == MVT::f64) && "Unknown FP VT!");
2298 MVT::ValueType IntVT = SrcEltVT == MVT::f32 ? MVT::i32 : MVT::i64;
2299 BV = ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(BV, IntVT).Val;
2303 // Now we know the input is an integer vector. If the output is a FP type,
2304 // convert to integer first, then to FP of the right size.
2305 if (MVT::isFloatingPoint(DstEltVT)) {
2306 assert((DstEltVT == MVT::f32 || DstEltVT == MVT::f64) && "Unknown FP VT!");
2307 MVT::ValueType TmpVT = DstEltVT == MVT::f32 ? MVT::i32 : MVT::i64;
2308 SDNode *Tmp = ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(BV, TmpVT).Val;
2310 // Next, convert to FP elements of the same size.
2311 return ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(Tmp, DstEltVT);
2314 // Okay, we know the src/dst types are both integers of differing types.
2315 // Handling growing first.
2316 assert(MVT::isInteger(SrcEltVT) && MVT::isInteger(DstEltVT));
2317 if (SrcBitSize < DstBitSize) {
2318 unsigned NumInputsPerOutput = DstBitSize/SrcBitSize;
2320 SmallVector<SDOperand, 8> Ops;
2321 for (unsigned i = 0, e = BV->getNumOperands()-2; i != e;
2322 i += NumInputsPerOutput) {
2323 bool isLE = TLI.isLittleEndian();
2324 uint64_t NewBits = 0;
2325 bool EltIsUndef = true;
2326 for (unsigned j = 0; j != NumInputsPerOutput; ++j) {
2327 // Shift the previously computed bits over.
2328 NewBits <<= SrcBitSize;
2329 SDOperand Op = BV->getOperand(i+ (isLE ? (NumInputsPerOutput-j-1) : j));
2330 if (Op.getOpcode() == ISD::UNDEF) continue;
2333 NewBits |= cast<ConstantSDNode>(Op)->getValue();
2337 Ops.push_back(DAG.getNode(ISD::UNDEF, DstEltVT));
2339 Ops.push_back(DAG.getConstant(NewBits, DstEltVT));
2342 Ops.push_back(DAG.getConstant(Ops.size(), MVT::i32)); // Add num elements.
2343 Ops.push_back(DAG.getValueType(DstEltVT)); // Add element size.
2344 return DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, &Ops[0], Ops.size());
2347 // Finally, this must be the case where we are shrinking elements: each input
2348 // turns into multiple outputs.
2349 unsigned NumOutputsPerInput = SrcBitSize/DstBitSize;
2350 SmallVector<SDOperand, 8> Ops;
2351 for (unsigned i = 0, e = BV->getNumOperands()-2; i != e; ++i) {
2352 if (BV->getOperand(i).getOpcode() == ISD::UNDEF) {
2353 for (unsigned j = 0; j != NumOutputsPerInput; ++j)
2354 Ops.push_back(DAG.getNode(ISD::UNDEF, DstEltVT));
2357 uint64_t OpVal = cast<ConstantSDNode>(BV->getOperand(i))->getValue();
2359 for (unsigned j = 0; j != NumOutputsPerInput; ++j) {
2360 unsigned ThisVal = OpVal & ((1ULL << DstBitSize)-1);
2361 OpVal >>= DstBitSize;
2362 Ops.push_back(DAG.getConstant(ThisVal, DstEltVT));
2365 // For big endian targets, swap the order of the pieces of each element.
2366 if (!TLI.isLittleEndian())
2367 std::reverse(Ops.end()-NumOutputsPerInput, Ops.end());
2369 Ops.push_back(DAG.getConstant(Ops.size(), MVT::i32)); // Add num elements.
2370 Ops.push_back(DAG.getValueType(DstEltVT)); // Add element size.
2371 return DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, &Ops[0], Ops.size());
2376 SDOperand DAGCombiner::visitFADD(SDNode *N) {
2377 SDOperand N0 = N->getOperand(0);
2378 SDOperand N1 = N->getOperand(1);
2379 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2380 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
2381 MVT::ValueType VT = N->getValueType(0);
2383 // fold (fadd c1, c2) -> c1+c2
2385 return DAG.getNode(ISD::FADD, VT, N0, N1);
2386 // canonicalize constant to RHS
2387 if (N0CFP && !N1CFP)
2388 return DAG.getNode(ISD::FADD, VT, N1, N0);
2389 // fold (A + (-B)) -> A-B
2390 if (N1.getOpcode() == ISD::FNEG)
2391 return DAG.getNode(ISD::FSUB, VT, N0, N1.getOperand(0));
2392 // fold ((-A) + B) -> B-A
2393 if (N0.getOpcode() == ISD::FNEG)
2394 return DAG.getNode(ISD::FSUB, VT, N1, N0.getOperand(0));
2398 SDOperand DAGCombiner::visitFSUB(SDNode *N) {
2399 SDOperand N0 = N->getOperand(0);
2400 SDOperand N1 = N->getOperand(1);
2401 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2402 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
2403 MVT::ValueType VT = N->getValueType(0);
2405 // fold (fsub c1, c2) -> c1-c2
2407 return DAG.getNode(ISD::FSUB, VT, N0, N1);
2408 // fold (A-(-B)) -> A+B
2409 if (N1.getOpcode() == ISD::FNEG)
2410 return DAG.getNode(ISD::FADD, VT, N0, N1.getOperand(0));
2414 SDOperand DAGCombiner::visitFMUL(SDNode *N) {
2415 SDOperand N0 = N->getOperand(0);
2416 SDOperand N1 = N->getOperand(1);
2417 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2418 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
2419 MVT::ValueType VT = N->getValueType(0);
2421 // fold (fmul c1, c2) -> c1*c2
2423 return DAG.getNode(ISD::FMUL, VT, N0, N1);
2424 // canonicalize constant to RHS
2425 if (N0CFP && !N1CFP)
2426 return DAG.getNode(ISD::FMUL, VT, N1, N0);
2427 // fold (fmul X, 2.0) -> (fadd X, X)
2428 if (N1CFP && N1CFP->isExactlyValue(+2.0))
2429 return DAG.getNode(ISD::FADD, VT, N0, N0);
2433 SDOperand DAGCombiner::visitFDIV(SDNode *N) {
2434 SDOperand N0 = N->getOperand(0);
2435 SDOperand N1 = N->getOperand(1);
2436 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2437 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
2438 MVT::ValueType VT = N->getValueType(0);
2440 // fold (fdiv c1, c2) -> c1/c2
2442 return DAG.getNode(ISD::FDIV, VT, N0, N1);
2446 SDOperand DAGCombiner::visitFREM(SDNode *N) {
2447 SDOperand N0 = N->getOperand(0);
2448 SDOperand N1 = N->getOperand(1);
2449 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2450 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
2451 MVT::ValueType VT = N->getValueType(0);
2453 // fold (frem c1, c2) -> fmod(c1,c2)
2455 return DAG.getNode(ISD::FREM, VT, N0, N1);
2459 SDOperand DAGCombiner::visitFCOPYSIGN(SDNode *N) {
2460 SDOperand N0 = N->getOperand(0);
2461 SDOperand N1 = N->getOperand(1);
2462 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2463 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
2464 MVT::ValueType VT = N->getValueType(0);
2466 if (N0CFP && N1CFP) // Constant fold
2467 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1);
2470 // copysign(x, c1) -> fabs(x) iff ispos(c1)
2471 // copysign(x, c1) -> fneg(fabs(x)) iff isneg(c1)
2476 u.d = N1CFP->getValue();
2478 return DAG.getNode(ISD::FABS, VT, N0);
2480 return DAG.getNode(ISD::FNEG, VT, DAG.getNode(ISD::FABS, VT, N0));
2483 // copysign(fabs(x), y) -> copysign(x, y)
2484 // copysign(fneg(x), y) -> copysign(x, y)
2485 // copysign(copysign(x,z), y) -> copysign(x, y)
2486 if (N0.getOpcode() == ISD::FABS || N0.getOpcode() == ISD::FNEG ||
2487 N0.getOpcode() == ISD::FCOPYSIGN)
2488 return DAG.getNode(ISD::FCOPYSIGN, VT, N0.getOperand(0), N1);
2490 // copysign(x, abs(y)) -> abs(x)
2491 if (N1.getOpcode() == ISD::FABS)
2492 return DAG.getNode(ISD::FABS, VT, N0);
2494 // copysign(x, copysign(y,z)) -> copysign(x, z)
2495 if (N1.getOpcode() == ISD::FCOPYSIGN)
2496 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1.getOperand(1));
2498 // copysign(x, fp_extend(y)) -> copysign(x, y)
2499 // copysign(x, fp_round(y)) -> copysign(x, y)
2500 if (N1.getOpcode() == ISD::FP_EXTEND || N1.getOpcode() == ISD::FP_ROUND)
2501 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1.getOperand(0));
2508 SDOperand DAGCombiner::visitSINT_TO_FP(SDNode *N) {
2509 SDOperand N0 = N->getOperand(0);
2510 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
2511 MVT::ValueType VT = N->getValueType(0);
2513 // fold (sint_to_fp c1) -> c1fp
2515 return DAG.getNode(ISD::SINT_TO_FP, VT, N0);
2519 SDOperand DAGCombiner::visitUINT_TO_FP(SDNode *N) {
2520 SDOperand N0 = N->getOperand(0);
2521 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
2522 MVT::ValueType VT = N->getValueType(0);
2524 // fold (uint_to_fp c1) -> c1fp
2526 return DAG.getNode(ISD::UINT_TO_FP, VT, N0);
2530 SDOperand DAGCombiner::visitFP_TO_SINT(SDNode *N) {
2531 SDOperand N0 = N->getOperand(0);
2532 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2533 MVT::ValueType VT = N->getValueType(0);
2535 // fold (fp_to_sint c1fp) -> c1
2537 return DAG.getNode(ISD::FP_TO_SINT, VT, N0);
2541 SDOperand DAGCombiner::visitFP_TO_UINT(SDNode *N) {
2542 SDOperand N0 = N->getOperand(0);
2543 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2544 MVT::ValueType VT = N->getValueType(0);
2546 // fold (fp_to_uint c1fp) -> c1
2548 return DAG.getNode(ISD::FP_TO_UINT, VT, N0);
2552 SDOperand DAGCombiner::visitFP_ROUND(SDNode *N) {
2553 SDOperand N0 = N->getOperand(0);
2554 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2555 MVT::ValueType VT = N->getValueType(0);
2557 // fold (fp_round c1fp) -> c1fp
2559 return DAG.getNode(ISD::FP_ROUND, VT, N0);
2561 // fold (fp_round (fp_extend x)) -> x
2562 if (N0.getOpcode() == ISD::FP_EXTEND && VT == N0.getOperand(0).getValueType())
2563 return N0.getOperand(0);
2565 // fold (fp_round (copysign X, Y)) -> (copysign (fp_round X), Y)
2566 if (N0.getOpcode() == ISD::FCOPYSIGN && N0.Val->hasOneUse()) {
2567 SDOperand Tmp = DAG.getNode(ISD::FP_ROUND, VT, N0.getOperand(0));
2568 AddToWorkList(Tmp.Val);
2569 return DAG.getNode(ISD::FCOPYSIGN, VT, Tmp, N0.getOperand(1));
2575 SDOperand DAGCombiner::visitFP_ROUND_INREG(SDNode *N) {
2576 SDOperand N0 = N->getOperand(0);
2577 MVT::ValueType VT = N->getValueType(0);
2578 MVT::ValueType EVT = cast<VTSDNode>(N->getOperand(1))->getVT();
2579 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2581 // fold (fp_round_inreg c1fp) -> c1fp
2583 SDOperand Round = DAG.getConstantFP(N0CFP->getValue(), EVT);
2584 return DAG.getNode(ISD::FP_EXTEND, VT, Round);
2589 SDOperand DAGCombiner::visitFP_EXTEND(SDNode *N) {
2590 SDOperand N0 = N->getOperand(0);
2591 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2592 MVT::ValueType VT = N->getValueType(0);
2594 // fold (fp_extend c1fp) -> c1fp
2596 return DAG.getNode(ISD::FP_EXTEND, VT, N0);
2598 // fold (fpext (load x)) -> (fpext (fpround (extload x)))
2599 if (ISD::isNON_EXTLoad(N0.Val) && N0.hasOneUse() &&
2600 (!AfterLegalize||TLI.isLoadXLegal(ISD::EXTLOAD, N0.getValueType()))) {
2601 LoadSDNode *LN0 = cast<LoadSDNode>(N0);
2602 SDOperand ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, VT, LN0->getChain(),
2603 LN0->getBasePtr(), LN0->getSrcValue(),
2604 LN0->getSrcValueOffset(),
2606 CombineTo(N, ExtLoad);
2607 CombineTo(N0.Val, DAG.getNode(ISD::FP_ROUND, N0.getValueType(), ExtLoad),
2608 ExtLoad.getValue(1));
2609 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
2616 SDOperand DAGCombiner::visitFNEG(SDNode *N) {
2617 SDOperand N0 = N->getOperand(0);
2618 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2619 MVT::ValueType VT = N->getValueType(0);
2621 // fold (fneg c1) -> -c1
2623 return DAG.getNode(ISD::FNEG, VT, N0);
2624 // fold (fneg (sub x, y)) -> (sub y, x)
2625 if (N0.getOpcode() == ISD::SUB)
2626 return DAG.getNode(ISD::SUB, VT, N0.getOperand(1), N0.getOperand(0));
2627 // fold (fneg (fneg x)) -> x
2628 if (N0.getOpcode() == ISD::FNEG)
2629 return N0.getOperand(0);
2633 SDOperand DAGCombiner::visitFABS(SDNode *N) {
2634 SDOperand N0 = N->getOperand(0);
2635 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2636 MVT::ValueType VT = N->getValueType(0);
2638 // fold (fabs c1) -> fabs(c1)
2640 return DAG.getNode(ISD::FABS, VT, N0);
2641 // fold (fabs (fabs x)) -> (fabs x)
2642 if (N0.getOpcode() == ISD::FABS)
2643 return N->getOperand(0);
2644 // fold (fabs (fneg x)) -> (fabs x)
2645 // fold (fabs (fcopysign x, y)) -> (fabs x)
2646 if (N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FCOPYSIGN)
2647 return DAG.getNode(ISD::FABS, VT, N0.getOperand(0));
2652 SDOperand DAGCombiner::visitBRCOND(SDNode *N) {
2653 SDOperand Chain = N->getOperand(0);
2654 SDOperand N1 = N->getOperand(1);
2655 SDOperand N2 = N->getOperand(2);
2656 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
2658 // never taken branch, fold to chain
2659 if (N1C && N1C->isNullValue())
2661 // unconditional branch
2662 if (N1C && N1C->getValue() == 1)
2663 return DAG.getNode(ISD::BR, MVT::Other, Chain, N2);
2664 // fold a brcond with a setcc condition into a BR_CC node if BR_CC is legal
2666 if (N1.getOpcode() == ISD::SETCC &&
2667 TLI.isOperationLegal(ISD::BR_CC, MVT::Other)) {
2668 return DAG.getNode(ISD::BR_CC, MVT::Other, Chain, N1.getOperand(2),
2669 N1.getOperand(0), N1.getOperand(1), N2);
2674 // Operand List for BR_CC: Chain, CondCC, CondLHS, CondRHS, DestBB.
2676 SDOperand DAGCombiner::visitBR_CC(SDNode *N) {
2677 CondCodeSDNode *CC = cast<CondCodeSDNode>(N->getOperand(1));
2678 SDOperand CondLHS = N->getOperand(2), CondRHS = N->getOperand(3);
2680 // Use SimplifySetCC to simplify SETCC's.
2681 SDOperand Simp = SimplifySetCC(MVT::i1, CondLHS, CondRHS, CC->get(), false);
2682 if (Simp.Val) AddToWorkList(Simp.Val);
2684 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(Simp.Val);
2686 // fold br_cc true, dest -> br dest (unconditional branch)
2687 if (SCCC && SCCC->getValue())
2688 return DAG.getNode(ISD::BR, MVT::Other, N->getOperand(0),
2690 // fold br_cc false, dest -> unconditional fall through
2691 if (SCCC && SCCC->isNullValue())
2692 return N->getOperand(0);
2694 // fold to a simpler setcc
2695 if (Simp.Val && Simp.getOpcode() == ISD::SETCC)
2696 return DAG.getNode(ISD::BR_CC, MVT::Other, N->getOperand(0),
2697 Simp.getOperand(2), Simp.getOperand(0),
2698 Simp.getOperand(1), N->getOperand(4));
2702 SDOperand DAGCombiner::visitLOAD(SDNode *N) {
2703 LoadSDNode *LD = cast<LoadSDNode>(N);
2704 SDOperand Chain = LD->getChain();
2705 SDOperand Ptr = LD->getBasePtr();
2707 // If there are no uses of the loaded value, change uses of the chain value
2708 // into uses of the chain input (i.e. delete the dead load).
2709 if (N->hasNUsesOfValue(0, 0))
2710 return CombineTo(N, DAG.getNode(ISD::UNDEF, N->getValueType(0)), Chain);
2712 // If this load is directly stored, replace the load value with the stored
2714 // TODO: Handle store large -> read small portion.
2715 // TODO: Handle TRUNCSTORE/LOADEXT
2716 if (LD->getExtensionType() == ISD::NON_EXTLOAD) {
2717 if (ISD::isNON_TRUNCStore(Chain.Val)) {
2718 StoreSDNode *PrevST = cast<StoreSDNode>(Chain);
2719 if (PrevST->getBasePtr() == Ptr &&
2720 PrevST->getValue().getValueType() == N->getValueType(0))
2721 return CombineTo(N, Chain.getOperand(1), Chain);
2726 // Walk up chain skipping non-aliasing memory nodes.
2727 SDOperand BetterChain = FindBetterChain(N, Chain);
2729 // If there is a better chain.
2730 if (Chain != BetterChain) {
2733 // Replace the chain to void dependency.
2734 if (LD->getExtensionType() == ISD::NON_EXTLOAD) {
2735 ReplLoad = DAG.getLoad(N->getValueType(0), BetterChain, Ptr,
2736 LD->getSrcValue(), LD->getSrcValueOffset());
2738 ReplLoad = DAG.getExtLoad(LD->getExtensionType(),
2739 LD->getValueType(0),
2740 BetterChain, Ptr, LD->getSrcValue(),
2741 LD->getSrcValueOffset(),
2745 // Create token factor to keep old chain connected.
2746 SDOperand Token = DAG.getNode(ISD::TokenFactor, MVT::Other,
2747 Chain, ReplLoad.getValue(1));
2749 // Replace uses with load result and token factor. Don't add users
2751 return CombineTo(N, ReplLoad.getValue(0), Token, false);
2758 SDOperand DAGCombiner::visitSTORE(SDNode *N) {
2759 StoreSDNode *ST = cast<StoreSDNode>(N);
2760 SDOperand Chain = ST->getChain();
2761 SDOperand Value = ST->getValue();
2762 SDOperand Ptr = ST->getBasePtr();
2764 // If this is a store of a bit convert, store the input value.
2765 // FIXME: This needs to know that the resultant store does not need a
2766 // higher alignment than the original.
2767 if (0 && Value.getOpcode() == ISD::BIT_CONVERT) {
2768 return DAG.getStore(Chain, Value.getOperand(0), Ptr, ST->getSrcValue(),
2769 ST->getSrcValueOffset());
2773 // Walk up chain skipping non-aliasing memory nodes.
2774 SDOperand BetterChain = FindBetterChain(N, Chain);
2776 // If there is a better chain.
2777 if (Chain != BetterChain) {
2778 // Replace the chain to avoid dependency.
2779 SDOperand ReplStore;
2780 if (ST->isTruncatingStore()) {
2781 ReplStore = DAG.getTruncStore(BetterChain, Value, Ptr,
2782 ST->getSrcValue(),ST->getSrcValueOffset(), ST->getStoredVT());
2784 ReplStore = DAG.getStore(BetterChain, Value, Ptr,
2785 ST->getSrcValue(), ST->getSrcValueOffset());
2788 // Create token to keep both nodes around.
2790 DAG.getNode(ISD::TokenFactor, MVT::Other, Chain, ReplStore);
2792 // Don't add users to work list.
2793 return CombineTo(N, Token, false);
2800 SDOperand DAGCombiner::visitINSERT_VECTOR_ELT(SDNode *N) {
2801 SDOperand InVec = N->getOperand(0);
2802 SDOperand InVal = N->getOperand(1);
2803 SDOperand EltNo = N->getOperand(2);
2805 // If the invec is a BUILD_VECTOR and if EltNo is a constant, build a new
2806 // vector with the inserted element.
2807 if (InVec.getOpcode() == ISD::BUILD_VECTOR && isa<ConstantSDNode>(EltNo)) {
2808 unsigned Elt = cast<ConstantSDNode>(EltNo)->getValue();
2809 SmallVector<SDOperand, 8> Ops(InVec.Val->op_begin(), InVec.Val->op_end());
2810 if (Elt < Ops.size())
2812 return DAG.getNode(ISD::BUILD_VECTOR, InVec.getValueType(),
2813 &Ops[0], Ops.size());
2819 SDOperand DAGCombiner::visitVINSERT_VECTOR_ELT(SDNode *N) {
2820 SDOperand InVec = N->getOperand(0);
2821 SDOperand InVal = N->getOperand(1);
2822 SDOperand EltNo = N->getOperand(2);
2823 SDOperand NumElts = N->getOperand(3);
2824 SDOperand EltType = N->getOperand(4);
2826 // If the invec is a VBUILD_VECTOR and if EltNo is a constant, build a new
2827 // vector with the inserted element.
2828 if (InVec.getOpcode() == ISD::VBUILD_VECTOR && isa<ConstantSDNode>(EltNo)) {
2829 unsigned Elt = cast<ConstantSDNode>(EltNo)->getValue();
2830 SmallVector<SDOperand, 8> Ops(InVec.Val->op_begin(), InVec.Val->op_end());
2831 if (Elt < Ops.size()-2)
2833 return DAG.getNode(ISD::VBUILD_VECTOR, InVec.getValueType(),
2834 &Ops[0], Ops.size());
2840 SDOperand DAGCombiner::visitVBUILD_VECTOR(SDNode *N) {
2841 unsigned NumInScalars = N->getNumOperands()-2;
2842 SDOperand NumElts = N->getOperand(NumInScalars);
2843 SDOperand EltType = N->getOperand(NumInScalars+1);
2845 // Check to see if this is a VBUILD_VECTOR of a bunch of VEXTRACT_VECTOR_ELT
2846 // operations. If so, and if the EXTRACT_ELT vector inputs come from at most
2847 // two distinct vectors, turn this into a shuffle node.
2848 SDOperand VecIn1, VecIn2;
2849 for (unsigned i = 0; i != NumInScalars; ++i) {
2850 // Ignore undef inputs.
2851 if (N->getOperand(i).getOpcode() == ISD::UNDEF) continue;
2853 // If this input is something other than a VEXTRACT_VECTOR_ELT with a
2854 // constant index, bail out.
2855 if (N->getOperand(i).getOpcode() != ISD::VEXTRACT_VECTOR_ELT ||
2856 !isa<ConstantSDNode>(N->getOperand(i).getOperand(1))) {
2857 VecIn1 = VecIn2 = SDOperand(0, 0);
2861 // If the input vector type disagrees with the result of the vbuild_vector,
2862 // we can't make a shuffle.
2863 SDOperand ExtractedFromVec = N->getOperand(i).getOperand(0);
2864 if (*(ExtractedFromVec.Val->op_end()-2) != NumElts ||
2865 *(ExtractedFromVec.Val->op_end()-1) != EltType) {
2866 VecIn1 = VecIn2 = SDOperand(0, 0);
2870 // Otherwise, remember this. We allow up to two distinct input vectors.
2871 if (ExtractedFromVec == VecIn1 || ExtractedFromVec == VecIn2)
2874 if (VecIn1.Val == 0) {
2875 VecIn1 = ExtractedFromVec;
2876 } else if (VecIn2.Val == 0) {
2877 VecIn2 = ExtractedFromVec;
2880 VecIn1 = VecIn2 = SDOperand(0, 0);
2885 // If everything is good, we can make a shuffle operation.
2887 SmallVector<SDOperand, 8> BuildVecIndices;
2888 for (unsigned i = 0; i != NumInScalars; ++i) {
2889 if (N->getOperand(i).getOpcode() == ISD::UNDEF) {
2890 BuildVecIndices.push_back(DAG.getNode(ISD::UNDEF, MVT::i32));
2894 SDOperand Extract = N->getOperand(i);
2896 // If extracting from the first vector, just use the index directly.
2897 if (Extract.getOperand(0) == VecIn1) {
2898 BuildVecIndices.push_back(Extract.getOperand(1));
2902 // Otherwise, use InIdx + VecSize
2903 unsigned Idx = cast<ConstantSDNode>(Extract.getOperand(1))->getValue();
2904 BuildVecIndices.push_back(DAG.getConstant(Idx+NumInScalars, MVT::i32));
2907 // Add count and size info.
2908 BuildVecIndices.push_back(NumElts);
2909 BuildVecIndices.push_back(DAG.getValueType(MVT::i32));
2911 // Return the new VVECTOR_SHUFFLE node.
2917 // Use an undef vbuild_vector as input for the second operand.
2918 std::vector<SDOperand> UnOps(NumInScalars,
2919 DAG.getNode(ISD::UNDEF,
2920 cast<VTSDNode>(EltType)->getVT()));
2921 UnOps.push_back(NumElts);
2922 UnOps.push_back(EltType);
2923 Ops[1] = DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector,
2924 &UnOps[0], UnOps.size());
2925 AddToWorkList(Ops[1].Val);
2927 Ops[2] = DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector,
2928 &BuildVecIndices[0], BuildVecIndices.size());
2931 return DAG.getNode(ISD::VVECTOR_SHUFFLE, MVT::Vector, Ops, 5);
2937 SDOperand DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) {
2938 SDOperand ShufMask = N->getOperand(2);
2939 unsigned NumElts = ShufMask.getNumOperands();
2941 // If the shuffle mask is an identity operation on the LHS, return the LHS.
2942 bool isIdentity = true;
2943 for (unsigned i = 0; i != NumElts; ++i) {
2944 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF &&
2945 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() != i) {
2950 if (isIdentity) return N->getOperand(0);
2952 // If the shuffle mask is an identity operation on the RHS, return the RHS.
2954 for (unsigned i = 0; i != NumElts; ++i) {
2955 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF &&
2956 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() != i+NumElts) {
2961 if (isIdentity) return N->getOperand(1);
2963 // Check if the shuffle is a unary shuffle, i.e. one of the vectors is not
2965 bool isUnary = true;
2966 bool isSplat = true;
2968 unsigned BaseIdx = 0;
2969 for (unsigned i = 0; i != NumElts; ++i)
2970 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF) {
2971 unsigned Idx = cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue();
2972 int V = (Idx < NumElts) ? 0 : 1;
2986 SDOperand N0 = N->getOperand(0);
2987 SDOperand N1 = N->getOperand(1);
2988 // Normalize unary shuffle so the RHS is undef.
2989 if (isUnary && VecNum == 1)
2992 // If it is a splat, check if the argument vector is a build_vector with
2993 // all scalar elements the same.
2996 if (V->getOpcode() == ISD::BIT_CONVERT)
2997 V = V->getOperand(0).Val;
2998 if (V->getOpcode() == ISD::BUILD_VECTOR) {
2999 unsigned NumElems = V->getNumOperands()-2;
3000 if (NumElems > BaseIdx) {
3002 bool AllSame = true;
3003 for (unsigned i = 0; i != NumElems; ++i) {
3004 if (V->getOperand(i).getOpcode() != ISD::UNDEF) {
3005 Base = V->getOperand(i);
3009 // Splat of <u, u, u, u>, return <u, u, u, u>
3012 for (unsigned i = 0; i != NumElems; ++i) {
3013 if (V->getOperand(i).getOpcode() != ISD::UNDEF &&
3014 V->getOperand(i) != Base) {
3019 // Splat of <x, x, x, x>, return <x, x, x, x>
3026 // If it is a unary or the LHS and the RHS are the same node, turn the RHS
3028 if (isUnary || N0 == N1) {
3029 if (N0.getOpcode() == ISD::UNDEF)
3030 return DAG.getNode(ISD::UNDEF, N->getValueType(0));
3031 // Check the SHUFFLE mask, mapping any inputs from the 2nd operand into the
3033 SmallVector<SDOperand, 8> MappedOps;
3034 for (unsigned i = 0, e = ShufMask.getNumOperands(); i != e; ++i) {
3035 if (ShufMask.getOperand(i).getOpcode() == ISD::UNDEF ||
3036 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() < NumElts) {
3037 MappedOps.push_back(ShufMask.getOperand(i));
3040 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() - NumElts;
3041 MappedOps.push_back(DAG.getConstant(NewIdx, MVT::i32));
3044 ShufMask = DAG.getNode(ISD::BUILD_VECTOR, ShufMask.getValueType(),
3045 &MappedOps[0], MappedOps.size());
3046 AddToWorkList(ShufMask.Val);
3047 return DAG.getNode(ISD::VECTOR_SHUFFLE, N->getValueType(0),
3049 DAG.getNode(ISD::UNDEF, N->getValueType(0)),
3056 SDOperand DAGCombiner::visitVVECTOR_SHUFFLE(SDNode *N) {
3057 SDOperand ShufMask = N->getOperand(2);
3058 unsigned NumElts = ShufMask.getNumOperands()-2;
3060 // If the shuffle mask is an identity operation on the LHS, return the LHS.
3061 bool isIdentity = true;
3062 for (unsigned i = 0; i != NumElts; ++i) {
3063 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF &&
3064 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() != i) {
3069 if (isIdentity) return N->getOperand(0);
3071 // If the shuffle mask is an identity operation on the RHS, return the RHS.
3073 for (unsigned i = 0; i != NumElts; ++i) {
3074 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF &&
3075 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() != i+NumElts) {
3080 if (isIdentity) return N->getOperand(1);
3082 // Check if the shuffle is a unary shuffle, i.e. one of the vectors is not
3084 bool isUnary = true;
3085 bool isSplat = true;
3087 unsigned BaseIdx = 0;
3088 for (unsigned i = 0; i != NumElts; ++i)
3089 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF) {
3090 unsigned Idx = cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue();
3091 int V = (Idx < NumElts) ? 0 : 1;
3105 SDOperand N0 = N->getOperand(0);
3106 SDOperand N1 = N->getOperand(1);
3107 // Normalize unary shuffle so the RHS is undef.
3108 if (isUnary && VecNum == 1)
3111 // If it is a splat, check if the argument vector is a build_vector with
3112 // all scalar elements the same.
3116 // If this is a vbit convert that changes the element type of the vector but
3117 // not the number of vector elements, look through it. Be careful not to
3118 // look though conversions that change things like v4f32 to v2f64.
3119 if (V->getOpcode() == ISD::VBIT_CONVERT) {
3120 SDOperand ConvInput = V->getOperand(0);
3121 if (ConvInput.getValueType() == MVT::Vector &&
3123 ConvInput.getConstantOperandVal(ConvInput.getNumOperands()-2))
3127 if (V->getOpcode() == ISD::VBUILD_VECTOR) {
3128 unsigned NumElems = V->getNumOperands()-2;
3129 if (NumElems > BaseIdx) {
3131 bool AllSame = true;
3132 for (unsigned i = 0; i != NumElems; ++i) {
3133 if (V->getOperand(i).getOpcode() != ISD::UNDEF) {
3134 Base = V->getOperand(i);
3138 // Splat of <u, u, u, u>, return <u, u, u, u>
3141 for (unsigned i = 0; i != NumElems; ++i) {
3142 if (V->getOperand(i).getOpcode() != ISD::UNDEF &&
3143 V->getOperand(i) != Base) {
3148 // Splat of <x, x, x, x>, return <x, x, x, x>
3155 // If it is a unary or the LHS and the RHS are the same node, turn the RHS
3157 if (isUnary || N0 == N1) {
3158 // Check the SHUFFLE mask, mapping any inputs from the 2nd operand into the
3160 SmallVector<SDOperand, 8> MappedOps;
3161 for (unsigned i = 0; i != NumElts; ++i) {
3162 if (ShufMask.getOperand(i).getOpcode() == ISD::UNDEF ||
3163 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() < NumElts) {
3164 MappedOps.push_back(ShufMask.getOperand(i));
3167 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() - NumElts;
3168 MappedOps.push_back(DAG.getConstant(NewIdx, MVT::i32));
3171 // Add the type/#elts values.
3172 MappedOps.push_back(ShufMask.getOperand(NumElts));
3173 MappedOps.push_back(ShufMask.getOperand(NumElts+1));
3175 ShufMask = DAG.getNode(ISD::VBUILD_VECTOR, ShufMask.getValueType(),
3176 &MappedOps[0], MappedOps.size());
3177 AddToWorkList(ShufMask.Val);
3179 // Build the undef vector.
3180 SDOperand UDVal = DAG.getNode(ISD::UNDEF, MappedOps[0].getValueType());
3181 for (unsigned i = 0; i != NumElts; ++i)
3182 MappedOps[i] = UDVal;
3183 MappedOps[NumElts ] = *(N0.Val->op_end()-2);
3184 MappedOps[NumElts+1] = *(N0.Val->op_end()-1);
3185 UDVal = DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector,
3186 &MappedOps[0], MappedOps.size());
3188 return DAG.getNode(ISD::VVECTOR_SHUFFLE, MVT::Vector,
3189 N0, UDVal, ShufMask,
3190 MappedOps[NumElts], MappedOps[NumElts+1]);
3196 /// XformToShuffleWithZero - Returns a vector_shuffle if it able to transform
3197 /// a VAND to a vector_shuffle with the destination vector and a zero vector.
3198 /// e.g. VAND V, <0xffffffff, 0, 0xffffffff, 0>. ==>
3199 /// vector_shuffle V, Zero, <0, 4, 2, 4>
3200 SDOperand DAGCombiner::XformToShuffleWithZero(SDNode *N) {
3201 SDOperand LHS = N->getOperand(0);
3202 SDOperand RHS = N->getOperand(1);
3203 if (N->getOpcode() == ISD::VAND) {
3204 SDOperand DstVecSize = *(LHS.Val->op_end()-2);
3205 SDOperand DstVecEVT = *(LHS.Val->op_end()-1);
3206 if (RHS.getOpcode() == ISD::VBIT_CONVERT)
3207 RHS = RHS.getOperand(0);
3208 if (RHS.getOpcode() == ISD::VBUILD_VECTOR) {
3209 std::vector<SDOperand> IdxOps;
3210 unsigned NumOps = RHS.getNumOperands();
3211 unsigned NumElts = NumOps-2;
3212 MVT::ValueType EVT = cast<VTSDNode>(RHS.getOperand(NumOps-1))->getVT();
3213 for (unsigned i = 0; i != NumElts; ++i) {
3214 SDOperand Elt = RHS.getOperand(i);
3215 if (!isa<ConstantSDNode>(Elt))
3217 else if (cast<ConstantSDNode>(Elt)->isAllOnesValue())
3218 IdxOps.push_back(DAG.getConstant(i, EVT));
3219 else if (cast<ConstantSDNode>(Elt)->isNullValue())
3220 IdxOps.push_back(DAG.getConstant(NumElts, EVT));
3225 // Let's see if the target supports this vector_shuffle.
3226 if (!TLI.isVectorClearMaskLegal(IdxOps, EVT, DAG))
3229 // Return the new VVECTOR_SHUFFLE node.
3230 SDOperand NumEltsNode = DAG.getConstant(NumElts, MVT::i32);
3231 SDOperand EVTNode = DAG.getValueType(EVT);
3232 std::vector<SDOperand> Ops;
3233 LHS = DAG.getNode(ISD::VBIT_CONVERT, MVT::Vector, LHS, NumEltsNode,
3236 AddToWorkList(LHS.Val);
3237 std::vector<SDOperand> ZeroOps(NumElts, DAG.getConstant(0, EVT));
3238 ZeroOps.push_back(NumEltsNode);
3239 ZeroOps.push_back(EVTNode);
3240 Ops.push_back(DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector,
3241 &ZeroOps[0], ZeroOps.size()));
3242 IdxOps.push_back(NumEltsNode);
3243 IdxOps.push_back(EVTNode);
3244 Ops.push_back(DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector,
3245 &IdxOps[0], IdxOps.size()));
3246 Ops.push_back(NumEltsNode);
3247 Ops.push_back(EVTNode);
3248 SDOperand Result = DAG.getNode(ISD::VVECTOR_SHUFFLE, MVT::Vector,
3249 &Ops[0], Ops.size());
3250 if (NumEltsNode != DstVecSize || EVTNode != DstVecEVT) {
3251 Result = DAG.getNode(ISD::VBIT_CONVERT, MVT::Vector, Result,
3252 DstVecSize, DstVecEVT);
3260 /// visitVBinOp - Visit a binary vector operation, like VADD. IntOp indicates
3261 /// the scalar operation of the vop if it is operating on an integer vector
3262 /// (e.g. ADD) and FPOp indicates the FP version (e.g. FADD).
3263 SDOperand DAGCombiner::visitVBinOp(SDNode *N, ISD::NodeType IntOp,
3264 ISD::NodeType FPOp) {
3265 MVT::ValueType EltType = cast<VTSDNode>(*(N->op_end()-1))->getVT();
3266 ISD::NodeType ScalarOp = MVT::isInteger(EltType) ? IntOp : FPOp;
3267 SDOperand LHS = N->getOperand(0);
3268 SDOperand RHS = N->getOperand(1);
3269 SDOperand Shuffle = XformToShuffleWithZero(N);
3270 if (Shuffle.Val) return Shuffle;
3272 // If the LHS and RHS are VBUILD_VECTOR nodes, see if we can constant fold
3274 if (LHS.getOpcode() == ISD::VBUILD_VECTOR &&
3275 RHS.getOpcode() == ISD::VBUILD_VECTOR) {
3276 SmallVector<SDOperand, 8> Ops;
3277 for (unsigned i = 0, e = LHS.getNumOperands()-2; i != e; ++i) {
3278 SDOperand LHSOp = LHS.getOperand(i);
3279 SDOperand RHSOp = RHS.getOperand(i);
3280 // If these two elements can't be folded, bail out.
3281 if ((LHSOp.getOpcode() != ISD::UNDEF &&
3282 LHSOp.getOpcode() != ISD::Constant &&
3283 LHSOp.getOpcode() != ISD::ConstantFP) ||
3284 (RHSOp.getOpcode() != ISD::UNDEF &&
3285 RHSOp.getOpcode() != ISD::Constant &&
3286 RHSOp.getOpcode() != ISD::ConstantFP))
3288 // Can't fold divide by zero.
3289 if (N->getOpcode() == ISD::VSDIV || N->getOpcode() == ISD::VUDIV) {
3290 if ((RHSOp.getOpcode() == ISD::Constant &&
3291 cast<ConstantSDNode>(RHSOp.Val)->isNullValue()) ||
3292 (RHSOp.getOpcode() == ISD::ConstantFP &&
3293 !cast<ConstantFPSDNode>(RHSOp.Val)->getValue()))
3296 Ops.push_back(DAG.getNode(ScalarOp, EltType, LHSOp, RHSOp));
3297 AddToWorkList(Ops.back().Val);
3298 assert((Ops.back().getOpcode() == ISD::UNDEF ||
3299 Ops.back().getOpcode() == ISD::Constant ||
3300 Ops.back().getOpcode() == ISD::ConstantFP) &&
3301 "Scalar binop didn't fold!");
3304 if (Ops.size() == LHS.getNumOperands()-2) {
3305 Ops.push_back(*(LHS.Val->op_end()-2));
3306 Ops.push_back(*(LHS.Val->op_end()-1));
3307 return DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, &Ops[0], Ops.size());
3314 SDOperand DAGCombiner::SimplifySelect(SDOperand N0, SDOperand N1, SDOperand N2){
3315 assert(N0.getOpcode() ==ISD::SETCC && "First argument must be a SetCC node!");
3317 SDOperand SCC = SimplifySelectCC(N0.getOperand(0), N0.getOperand(1), N1, N2,
3318 cast<CondCodeSDNode>(N0.getOperand(2))->get());
3319 // If we got a simplified select_cc node back from SimplifySelectCC, then
3320 // break it down into a new SETCC node, and a new SELECT node, and then return
3321 // the SELECT node, since we were called with a SELECT node.
3323 // Check to see if we got a select_cc back (to turn into setcc/select).
3324 // Otherwise, just return whatever node we got back, like fabs.
3325 if (SCC.getOpcode() == ISD::SELECT_CC) {
3326 SDOperand SETCC = DAG.getNode(ISD::SETCC, N0.getValueType(),
3327 SCC.getOperand(0), SCC.getOperand(1),
3329 AddToWorkList(SETCC.Val);
3330 return DAG.getNode(ISD::SELECT, SCC.getValueType(), SCC.getOperand(2),
3331 SCC.getOperand(3), SETCC);
3338 /// SimplifySelectOps - Given a SELECT or a SELECT_CC node, where LHS and RHS
3339 /// are the two values being selected between, see if we can simplify the
3340 /// select. Callers of this should assume that TheSelect is deleted if this
3341 /// returns true. As such, they should return the appropriate thing (e.g. the
3342 /// node) back to the top-level of the DAG combiner loop to avoid it being
3345 bool DAGCombiner::SimplifySelectOps(SDNode *TheSelect, SDOperand LHS,
3348 // If this is a select from two identical things, try to pull the operation
3349 // through the select.
3350 if (LHS.getOpcode() == RHS.getOpcode() && LHS.hasOneUse() && RHS.hasOneUse()){
3351 // If this is a load and the token chain is identical, replace the select
3352 // of two loads with a load through a select of the address to load from.
3353 // This triggers in things like "select bool X, 10.0, 123.0" after the FP
3354 // constants have been dropped into the constant pool.
3355 if (LHS.getOpcode() == ISD::LOAD &&
3356 // Token chains must be identical.
3357 LHS.getOperand(0) == RHS.getOperand(0)) {
3358 LoadSDNode *LLD = cast<LoadSDNode>(LHS);
3359 LoadSDNode *RLD = cast<LoadSDNode>(RHS);
3361 // If this is an EXTLOAD, the VT's must match.
3362 if (LLD->getLoadedVT() == RLD->getLoadedVT()) {
3363 // FIXME: this conflates two src values, discarding one. This is not
3364 // the right thing to do, but nothing uses srcvalues now. When they do,
3365 // turn SrcValue into a list of locations.
3367 if (TheSelect->getOpcode() == ISD::SELECT)
3368 Addr = DAG.getNode(ISD::SELECT, LLD->getBasePtr().getValueType(),
3369 TheSelect->getOperand(0), LLD->getBasePtr(),
3372 Addr = DAG.getNode(ISD::SELECT_CC, LLD->getBasePtr().getValueType(),
3373 TheSelect->getOperand(0),
3374 TheSelect->getOperand(1),
3375 LLD->getBasePtr(), RLD->getBasePtr(),
3376 TheSelect->getOperand(4));
3379 if (LLD->getExtensionType() == ISD::NON_EXTLOAD)
3380 Load = DAG.getLoad(TheSelect->getValueType(0), LLD->getChain(),
3381 Addr,LLD->getSrcValue(), LLD->getSrcValueOffset());
3383 Load = DAG.getExtLoad(LLD->getExtensionType(),
3384 TheSelect->getValueType(0),
3385 LLD->getChain(), Addr, LLD->getSrcValue(),
3386 LLD->getSrcValueOffset(),
3387 LLD->getLoadedVT());
3389 // Users of the select now use the result of the load.
3390 CombineTo(TheSelect, Load);
3392 // Users of the old loads now use the new load's chain. We know the
3393 // old-load value is dead now.
3394 CombineTo(LHS.Val, Load.getValue(0), Load.getValue(1));
3395 CombineTo(RHS.Val, Load.getValue(0), Load.getValue(1));
3404 SDOperand DAGCombiner::SimplifySelectCC(SDOperand N0, SDOperand N1,
3405 SDOperand N2, SDOperand N3,
3408 MVT::ValueType VT = N2.getValueType();
3409 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
3410 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2.Val);
3411 ConstantSDNode *N3C = dyn_cast<ConstantSDNode>(N3.Val);
3413 // Determine if the condition we're dealing with is constant
3414 SDOperand SCC = SimplifySetCC(TLI.getSetCCResultTy(), N0, N1, CC, false);
3415 if (SCC.Val) AddToWorkList(SCC.Val);
3416 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.Val);
3418 // fold select_cc true, x, y -> x
3419 if (SCCC && SCCC->getValue())
3421 // fold select_cc false, x, y -> y
3422 if (SCCC && SCCC->getValue() == 0)
3425 // Check to see if we can simplify the select into an fabs node
3426 if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N1)) {
3427 // Allow either -0.0 or 0.0
3428 if (CFP->getValue() == 0.0) {
3429 // select (setg[te] X, +/-0.0), X, fneg(X) -> fabs
3430 if ((CC == ISD::SETGE || CC == ISD::SETGT) &&
3431 N0 == N2 && N3.getOpcode() == ISD::FNEG &&
3432 N2 == N3.getOperand(0))
3433 return DAG.getNode(ISD::FABS, VT, N0);
3435 // select (setl[te] X, +/-0.0), fneg(X), X -> fabs
3436 if ((CC == ISD::SETLT || CC == ISD::SETLE) &&
3437 N0 == N3 && N2.getOpcode() == ISD::FNEG &&
3438 N2.getOperand(0) == N3)
3439 return DAG.getNode(ISD::FABS, VT, N3);
3443 // Check to see if we can perform the "gzip trick", transforming
3444 // select_cc setlt X, 0, A, 0 -> and (sra X, size(X)-1), A
3445 if (N1C && N3C && N3C->isNullValue() && CC == ISD::SETLT &&
3446 MVT::isInteger(N0.getValueType()) &&
3447 MVT::isInteger(N2.getValueType()) &&
3448 (N1C->isNullValue() || // (a < 0) ? b : 0
3449 (N1C->getValue() == 1 && N0 == N2))) { // (a < 1) ? a : 0
3450 MVT::ValueType XType = N0.getValueType();
3451 MVT::ValueType AType = N2.getValueType();
3452 if (XType >= AType) {
3453 // and (sra X, size(X)-1, A) -> "and (srl X, C2), A" iff A is a
3454 // single-bit constant.
3455 if (N2C && ((N2C->getValue() & (N2C->getValue()-1)) == 0)) {
3456 unsigned ShCtV = Log2_64(N2C->getValue());
3457 ShCtV = MVT::getSizeInBits(XType)-ShCtV-1;
3458 SDOperand ShCt = DAG.getConstant(ShCtV, TLI.getShiftAmountTy());
3459 SDOperand Shift = DAG.getNode(ISD::SRL, XType, N0, ShCt);
3460 AddToWorkList(Shift.Val);
3461 if (XType > AType) {
3462 Shift = DAG.getNode(ISD::TRUNCATE, AType, Shift);
3463 AddToWorkList(Shift.Val);
3465 return DAG.getNode(ISD::AND, AType, Shift, N2);
3467 SDOperand Shift = DAG.getNode(ISD::SRA, XType, N0,
3468 DAG.getConstant(MVT::getSizeInBits(XType)-1,
3469 TLI.getShiftAmountTy()));
3470 AddToWorkList(Shift.Val);
3471 if (XType > AType) {
3472 Shift = DAG.getNode(ISD::TRUNCATE, AType, Shift);
3473 AddToWorkList(Shift.Val);
3475 return DAG.getNode(ISD::AND, AType, Shift, N2);
3479 // fold select C, 16, 0 -> shl C, 4
3480 if (N2C && N3C && N3C->isNullValue() && isPowerOf2_64(N2C->getValue()) &&
3481 TLI.getSetCCResultContents() == TargetLowering::ZeroOrOneSetCCResult) {
3482 // Get a SetCC of the condition
3483 // FIXME: Should probably make sure that setcc is legal if we ever have a
3484 // target where it isn't.
3485 SDOperand Temp, SCC;
3486 // cast from setcc result type to select result type
3487 if (AfterLegalize) {
3488 SCC = DAG.getSetCC(TLI.getSetCCResultTy(), N0, N1, CC);
3489 Temp = DAG.getZeroExtendInReg(SCC, N2.getValueType());
3491 SCC = DAG.getSetCC(MVT::i1, N0, N1, CC);
3492 Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getValueType(), SCC);
3494 AddToWorkList(SCC.Val);
3495 AddToWorkList(Temp.Val);
3496 // shl setcc result by log2 n2c
3497 return DAG.getNode(ISD::SHL, N2.getValueType(), Temp,
3498 DAG.getConstant(Log2_64(N2C->getValue()),
3499 TLI.getShiftAmountTy()));
3502 // Check to see if this is the equivalent of setcc
3503 // FIXME: Turn all of these into setcc if setcc if setcc is legal
3504 // otherwise, go ahead with the folds.
3505 if (0 && N3C && N3C->isNullValue() && N2C && (N2C->getValue() == 1ULL)) {
3506 MVT::ValueType XType = N0.getValueType();
3507 if (TLI.isOperationLegal(ISD::SETCC, TLI.getSetCCResultTy())) {
3508 SDOperand Res = DAG.getSetCC(TLI.getSetCCResultTy(), N0, N1, CC);
3509 if (Res.getValueType() != VT)
3510 Res = DAG.getNode(ISD::ZERO_EXTEND, VT, Res);
3514 // seteq X, 0 -> srl (ctlz X, log2(size(X)))
3515 if (N1C && N1C->isNullValue() && CC == ISD::SETEQ &&
3516 TLI.isOperationLegal(ISD::CTLZ, XType)) {
3517 SDOperand Ctlz = DAG.getNode(ISD::CTLZ, XType, N0);
3518 return DAG.getNode(ISD::SRL, XType, Ctlz,
3519 DAG.getConstant(Log2_32(MVT::getSizeInBits(XType)),
3520 TLI.getShiftAmountTy()));
3522 // setgt X, 0 -> srl (and (-X, ~X), size(X)-1)
3523 if (N1C && N1C->isNullValue() && CC == ISD::SETGT) {
3524 SDOperand NegN0 = DAG.getNode(ISD::SUB, XType, DAG.getConstant(0, XType),
3526 SDOperand NotN0 = DAG.getNode(ISD::XOR, XType, N0,
3527 DAG.getConstant(~0ULL, XType));
3528 return DAG.getNode(ISD::SRL, XType,
3529 DAG.getNode(ISD::AND, XType, NegN0, NotN0),
3530 DAG.getConstant(MVT::getSizeInBits(XType)-1,
3531 TLI.getShiftAmountTy()));
3533 // setgt X, -1 -> xor (srl (X, size(X)-1), 1)
3534 if (N1C && N1C->isAllOnesValue() && CC == ISD::SETGT) {
3535 SDOperand Sign = DAG.getNode(ISD::SRL, XType, N0,
3536 DAG.getConstant(MVT::getSizeInBits(XType)-1,
3537 TLI.getShiftAmountTy()));
3538 return DAG.getNode(ISD::XOR, XType, Sign, DAG.getConstant(1, XType));
3542 // Check to see if this is an integer abs. select_cc setl[te] X, 0, -X, X ->
3543 // Y = sra (X, size(X)-1); xor (add (X, Y), Y)
3544 if (N1C && N1C->isNullValue() && (CC == ISD::SETLT || CC == ISD::SETLE) &&
3545 N0 == N3 && N2.getOpcode() == ISD::SUB && N0 == N2.getOperand(1)) {
3546 if (ConstantSDNode *SubC = dyn_cast<ConstantSDNode>(N2.getOperand(0))) {
3547 MVT::ValueType XType = N0.getValueType();
3548 if (SubC->isNullValue() && MVT::isInteger(XType)) {
3549 SDOperand Shift = DAG.getNode(ISD::SRA, XType, N0,
3550 DAG.getConstant(MVT::getSizeInBits(XType)-1,
3551 TLI.getShiftAmountTy()));
3552 SDOperand Add = DAG.getNode(ISD::ADD, XType, N0, Shift);
3553 AddToWorkList(Shift.Val);
3554 AddToWorkList(Add.Val);
3555 return DAG.getNode(ISD::XOR, XType, Add, Shift);
3563 SDOperand DAGCombiner::SimplifySetCC(MVT::ValueType VT, SDOperand N0,
3564 SDOperand N1, ISD::CondCode Cond,
3565 bool foldBooleans) {
3566 // These setcc operations always fold.
3570 case ISD::SETFALSE2: return DAG.getConstant(0, VT);
3572 case ISD::SETTRUE2: return DAG.getConstant(1, VT);
3575 if (ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val)) {
3576 uint64_t C1 = N1C->getValue();
3577 if (isa<ConstantSDNode>(N0.Val)) {
3578 return DAG.FoldSetCC(VT, N0, N1, Cond);
3580 // If the LHS is '(srl (ctlz x), 5)', the RHS is 0/1, and this is an
3581 // equality comparison, then we're just comparing whether X itself is
3583 if (N0.getOpcode() == ISD::SRL && (C1 == 0 || C1 == 1) &&
3584 N0.getOperand(0).getOpcode() == ISD::CTLZ &&
3585 N0.getOperand(1).getOpcode() == ISD::Constant) {
3586 unsigned ShAmt = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
3587 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
3588 ShAmt == Log2_32(MVT::getSizeInBits(N0.getValueType()))) {
3589 if ((C1 == 0) == (Cond == ISD::SETEQ)) {
3590 // (srl (ctlz x), 5) == 0 -> X != 0
3591 // (srl (ctlz x), 5) != 1 -> X != 0
3594 // (srl (ctlz x), 5) != 0 -> X == 0
3595 // (srl (ctlz x), 5) == 1 -> X == 0
3598 SDOperand Zero = DAG.getConstant(0, N0.getValueType());
3599 return DAG.getSetCC(VT, N0.getOperand(0).getOperand(0),
3604 // If the LHS is a ZERO_EXTEND, perform the comparison on the input.
3605 if (N0.getOpcode() == ISD::ZERO_EXTEND) {
3606 unsigned InSize = MVT::getSizeInBits(N0.getOperand(0).getValueType());
3608 // If the comparison constant has bits in the upper part, the
3609 // zero-extended value could never match.
3610 if (C1 & (~0ULL << InSize)) {
3611 unsigned VSize = MVT::getSizeInBits(N0.getValueType());
3615 case ISD::SETEQ: return DAG.getConstant(0, VT);
3618 case ISD::SETNE: return DAG.getConstant(1, VT);
3621 // True if the sign bit of C1 is set.
3622 return DAG.getConstant((C1 & (1ULL << VSize)) != 0, VT);
3625 // True if the sign bit of C1 isn't set.
3626 return DAG.getConstant((C1 & (1ULL << VSize)) == 0, VT);
3632 // Otherwise, we can perform the comparison with the low bits.
3640 return DAG.getSetCC(VT, N0.getOperand(0),
3641 DAG.getConstant(C1, N0.getOperand(0).getValueType()),
3644 break; // todo, be more careful with signed comparisons
3646 } else if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
3647 (Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
3648 MVT::ValueType ExtSrcTy = cast<VTSDNode>(N0.getOperand(1))->getVT();
3649 unsigned ExtSrcTyBits = MVT::getSizeInBits(ExtSrcTy);
3650 MVT::ValueType ExtDstTy = N0.getValueType();
3651 unsigned ExtDstTyBits = MVT::getSizeInBits(ExtDstTy);
3653 // If the extended part has any inconsistent bits, it cannot ever
3654 // compare equal. In other words, they have to be all ones or all
3657 (~0ULL >> (64-ExtSrcTyBits)) & (~0ULL << (ExtDstTyBits-1));
3658 if ((C1 & ExtBits) != 0 && (C1 & ExtBits) != ExtBits)
3659 return DAG.getConstant(Cond == ISD::SETNE, VT);
3662 MVT::ValueType Op0Ty = N0.getOperand(0).getValueType();
3663 if (Op0Ty == ExtSrcTy) {
3664 ZextOp = N0.getOperand(0);
3666 int64_t Imm = ~0ULL >> (64-ExtSrcTyBits);
3667 ZextOp = DAG.getNode(ISD::AND, Op0Ty, N0.getOperand(0),
3668 DAG.getConstant(Imm, Op0Ty));
3670 AddToWorkList(ZextOp.Val);
3671 // Otherwise, make this a use of a zext.
3672 return DAG.getSetCC(VT, ZextOp,
3673 DAG.getConstant(C1 & (~0ULL>>(64-ExtSrcTyBits)),
3676 } else if ((N1C->getValue() == 0 || N1C->getValue() == 1) &&
3677 (Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
3679 // SETCC (SETCC), [0|1], [EQ|NE] -> SETCC
3680 if (N0.getOpcode() == ISD::SETCC) {
3681 bool TrueWhenTrue = (Cond == ISD::SETEQ) ^ (N1C->getValue() != 1);
3685 // Invert the condition.
3686 ISD::CondCode CC = cast<CondCodeSDNode>(N0.getOperand(2))->get();
3687 CC = ISD::getSetCCInverse(CC,
3688 MVT::isInteger(N0.getOperand(0).getValueType()));
3689 return DAG.getSetCC(VT, N0.getOperand(0), N0.getOperand(1), CC);
3692 if ((N0.getOpcode() == ISD::XOR ||
3693 (N0.getOpcode() == ISD::AND &&
3694 N0.getOperand(0).getOpcode() == ISD::XOR &&
3695 N0.getOperand(1) == N0.getOperand(0).getOperand(1))) &&
3696 isa<ConstantSDNode>(N0.getOperand(1)) &&
3697 cast<ConstantSDNode>(N0.getOperand(1))->getValue() == 1) {
3698 // If this is (X^1) == 0/1, swap the RHS and eliminate the xor. We
3699 // can only do this if the top bits are known zero.
3700 if (TLI.MaskedValueIsZero(N0,
3701 MVT::getIntVTBitMask(N0.getValueType())-1)){
3702 // Okay, get the un-inverted input value.
3704 if (N0.getOpcode() == ISD::XOR)
3705 Val = N0.getOperand(0);
3707 assert(N0.getOpcode() == ISD::AND &&
3708 N0.getOperand(0).getOpcode() == ISD::XOR);
3709 // ((X^1)&1)^1 -> X & 1
3710 Val = DAG.getNode(ISD::AND, N0.getValueType(),
3711 N0.getOperand(0).getOperand(0),
3714 return DAG.getSetCC(VT, Val, N1,
3715 Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
3720 uint64_t MinVal, MaxVal;
3721 unsigned OperandBitSize = MVT::getSizeInBits(N1C->getValueType(0));
3722 if (ISD::isSignedIntSetCC(Cond)) {
3723 MinVal = 1ULL << (OperandBitSize-1);
3724 if (OperandBitSize != 1) // Avoid X >> 64, which is undefined.
3725 MaxVal = ~0ULL >> (65-OperandBitSize);
3730 MaxVal = ~0ULL >> (64-OperandBitSize);
3733 // Canonicalize GE/LE comparisons to use GT/LT comparisons.
3734 if (Cond == ISD::SETGE || Cond == ISD::SETUGE) {
3735 if (C1 == MinVal) return DAG.getConstant(1, VT); // X >= MIN --> true
3736 --C1; // X >= C0 --> X > (C0-1)
3737 return DAG.getSetCC(VT, N0, DAG.getConstant(C1, N1.getValueType()),
3738 (Cond == ISD::SETGE) ? ISD::SETGT : ISD::SETUGT);
3741 if (Cond == ISD::SETLE || Cond == ISD::SETULE) {
3742 if (C1 == MaxVal) return DAG.getConstant(1, VT); // X <= MAX --> true
3743 ++C1; // X <= C0 --> X < (C0+1)
3744 return DAG.getSetCC(VT, N0, DAG.getConstant(C1, N1.getValueType()),
3745 (Cond == ISD::SETLE) ? ISD::SETLT : ISD::SETULT);
3748 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MinVal)
3749 return DAG.getConstant(0, VT); // X < MIN --> false
3751 // Canonicalize setgt X, Min --> setne X, Min
3752 if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MinVal)
3753 return DAG.getSetCC(VT, N0, N1, ISD::SETNE);
3754 // Canonicalize setlt X, Max --> setne X, Max
3755 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MaxVal)
3756 return DAG.getSetCC(VT, N0, N1, ISD::SETNE);
3758 // If we have setult X, 1, turn it into seteq X, 0
3759 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MinVal+1)
3760 return DAG.getSetCC(VT, N0, DAG.getConstant(MinVal, N0.getValueType()),
3762 // If we have setugt X, Max-1, turn it into seteq X, Max
3763 else if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MaxVal-1)
3764 return DAG.getSetCC(VT, N0, DAG.getConstant(MaxVal, N0.getValueType()),
3767 // If we have "setcc X, C0", check to see if we can shrink the immediate
3770 // SETUGT X, SINTMAX -> SETLT X, 0
3771 if (Cond == ISD::SETUGT && OperandBitSize != 1 &&
3772 C1 == (~0ULL >> (65-OperandBitSize)))
3773 return DAG.getSetCC(VT, N0, DAG.getConstant(0, N1.getValueType()),
3776 // FIXME: Implement the rest of these.
3778 // Fold bit comparisons when we can.
3779 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
3780 VT == N0.getValueType() && N0.getOpcode() == ISD::AND)
3781 if (ConstantSDNode *AndRHS =
3782 dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
3783 if (Cond == ISD::SETNE && C1 == 0) {// (X & 8) != 0 --> (X & 8) >> 3
3784 // Perform the xform if the AND RHS is a single bit.
3785 if (isPowerOf2_64(AndRHS->getValue())) {
3786 return DAG.getNode(ISD::SRL, VT, N0,
3787 DAG.getConstant(Log2_64(AndRHS->getValue()),
3788 TLI.getShiftAmountTy()));
3790 } else if (Cond == ISD::SETEQ && C1 == AndRHS->getValue()) {
3791 // (X & 8) == 8 --> (X & 8) >> 3
3792 // Perform the xform if C1 is a single bit.
3793 if (isPowerOf2_64(C1)) {
3794 return DAG.getNode(ISD::SRL, VT, N0,
3795 DAG.getConstant(Log2_64(C1),TLI.getShiftAmountTy()));
3800 } else if (isa<ConstantSDNode>(N0.Val)) {
3801 // Ensure that the constant occurs on the RHS.
3802 return DAG.getSetCC(VT, N1, N0, ISD::getSetCCSwappedOperands(Cond));
3805 if (isa<ConstantFPSDNode>(N0.Val)) {
3806 // Constant fold or commute setcc.
3807 SDOperand O = DAG.FoldSetCC(VT, N0, N1, Cond);
3808 if (O.Val) return O;
3812 // We can always fold X == X for integer setcc's.
3813 if (MVT::isInteger(N0.getValueType()))
3814 return DAG.getConstant(ISD::isTrueWhenEqual(Cond), VT);
3815 unsigned UOF = ISD::getUnorderedFlavor(Cond);
3816 if (UOF == 2) // FP operators that are undefined on NaNs.
3817 return DAG.getConstant(ISD::isTrueWhenEqual(Cond), VT);
3818 if (UOF == unsigned(ISD::isTrueWhenEqual(Cond)))
3819 return DAG.getConstant(UOF, VT);
3820 // Otherwise, we can't fold it. However, we can simplify it to SETUO/SETO
3821 // if it is not already.
3822 ISD::CondCode NewCond = UOF == 0 ? ISD::SETO : ISD::SETUO;
3823 if (NewCond != Cond)
3824 return DAG.getSetCC(VT, N0, N1, NewCond);
3827 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
3828 MVT::isInteger(N0.getValueType())) {
3829 if (N0.getOpcode() == ISD::ADD || N0.getOpcode() == ISD::SUB ||
3830 N0.getOpcode() == ISD::XOR) {
3831 // Simplify (X+Y) == (X+Z) --> Y == Z
3832 if (N0.getOpcode() == N1.getOpcode()) {
3833 if (N0.getOperand(0) == N1.getOperand(0))
3834 return DAG.getSetCC(VT, N0.getOperand(1), N1.getOperand(1), Cond);
3835 if (N0.getOperand(1) == N1.getOperand(1))
3836 return DAG.getSetCC(VT, N0.getOperand(0), N1.getOperand(0), Cond);
3837 if (DAG.isCommutativeBinOp(N0.getOpcode())) {
3838 // If X op Y == Y op X, try other combinations.
3839 if (N0.getOperand(0) == N1.getOperand(1))
3840 return DAG.getSetCC(VT, N0.getOperand(1), N1.getOperand(0), Cond);
3841 if (N0.getOperand(1) == N1.getOperand(0))
3842 return DAG.getSetCC(VT, N0.getOperand(0), N1.getOperand(1), Cond);
3846 if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(N1)) {
3847 if (ConstantSDNode *LHSR = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
3848 // Turn (X+C1) == C2 --> X == C2-C1
3849 if (N0.getOpcode() == ISD::ADD && N0.Val->hasOneUse()) {
3850 return DAG.getSetCC(VT, N0.getOperand(0),
3851 DAG.getConstant(RHSC->getValue()-LHSR->getValue(),
3852 N0.getValueType()), Cond);
3855 // Turn (X^C1) == C2 into X == C1^C2 iff X&~C1 = 0.
3856 if (N0.getOpcode() == ISD::XOR)
3857 // If we know that all of the inverted bits are zero, don't bother
3858 // performing the inversion.
3859 if (TLI.MaskedValueIsZero(N0.getOperand(0), ~LHSR->getValue()))
3860 return DAG.getSetCC(VT, N0.getOperand(0),
3861 DAG.getConstant(LHSR->getValue()^RHSC->getValue(),
3862 N0.getValueType()), Cond);
3865 // Turn (C1-X) == C2 --> X == C1-C2
3866 if (ConstantSDNode *SUBC = dyn_cast<ConstantSDNode>(N0.getOperand(0))) {
3867 if (N0.getOpcode() == ISD::SUB && N0.Val->hasOneUse()) {
3868 return DAG.getSetCC(VT, N0.getOperand(1),
3869 DAG.getConstant(SUBC->getValue()-RHSC->getValue(),
3870 N0.getValueType()), Cond);
3875 // Simplify (X+Z) == X --> Z == 0
3876 if (N0.getOperand(0) == N1)
3877 return DAG.getSetCC(VT, N0.getOperand(1),
3878 DAG.getConstant(0, N0.getValueType()), Cond);
3879 if (N0.getOperand(1) == N1) {
3880 if (DAG.isCommutativeBinOp(N0.getOpcode()))
3881 return DAG.getSetCC(VT, N0.getOperand(0),
3882 DAG.getConstant(0, N0.getValueType()), Cond);
3884 assert(N0.getOpcode() == ISD::SUB && "Unexpected operation!");
3885 // (Z-X) == X --> Z == X<<1
3886 SDOperand SH = DAG.getNode(ISD::SHL, N1.getValueType(),
3888 DAG.getConstant(1,TLI.getShiftAmountTy()));
3889 AddToWorkList(SH.Val);
3890 return DAG.getSetCC(VT, N0.getOperand(0), SH, Cond);
3895 if (N1.getOpcode() == ISD::ADD || N1.getOpcode() == ISD::SUB ||
3896 N1.getOpcode() == ISD::XOR) {
3897 // Simplify X == (X+Z) --> Z == 0
3898 if (N1.getOperand(0) == N0) {
3899 return DAG.getSetCC(VT, N1.getOperand(1),
3900 DAG.getConstant(0, N1.getValueType()), Cond);
3901 } else if (N1.getOperand(1) == N0) {
3902 if (DAG.isCommutativeBinOp(N1.getOpcode())) {
3903 return DAG.getSetCC(VT, N1.getOperand(0),
3904 DAG.getConstant(0, N1.getValueType()), Cond);
3906 assert(N1.getOpcode() == ISD::SUB && "Unexpected operation!");
3907 // X == (Z-X) --> X<<1 == Z
3908 SDOperand SH = DAG.getNode(ISD::SHL, N1.getValueType(), N0,
3909 DAG.getConstant(1,TLI.getShiftAmountTy()));
3910 AddToWorkList(SH.Val);
3911 return DAG.getSetCC(VT, SH, N1.getOperand(0), Cond);
3917 // Fold away ALL boolean setcc's.
3919 if (N0.getValueType() == MVT::i1 && foldBooleans) {
3921 default: assert(0 && "Unknown integer setcc!");
3922 case ISD::SETEQ: // X == Y -> (X^Y)^1
3923 Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, N1);
3924 N0 = DAG.getNode(ISD::XOR, MVT::i1, Temp, DAG.getConstant(1, MVT::i1));
3925 AddToWorkList(Temp.Val);
3927 case ISD::SETNE: // X != Y --> (X^Y)
3928 N0 = DAG.getNode(ISD::XOR, MVT::i1, N0, N1);
3930 case ISD::SETGT: // X >s Y --> X == 0 & Y == 1 --> X^1 & Y
3931 case ISD::SETULT: // X <u Y --> X == 0 & Y == 1 --> X^1 & Y
3932 Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, DAG.getConstant(1, MVT::i1));
3933 N0 = DAG.getNode(ISD::AND, MVT::i1, N1, Temp);
3934 AddToWorkList(Temp.Val);
3936 case ISD::SETLT: // X <s Y --> X == 1 & Y == 0 --> Y^1 & X
3937 case ISD::SETUGT: // X >u Y --> X == 1 & Y == 0 --> Y^1 & X
3938 Temp = DAG.getNode(ISD::XOR, MVT::i1, N1, DAG.getConstant(1, MVT::i1));
3939 N0 = DAG.getNode(ISD::AND, MVT::i1, N0, Temp);
3940 AddToWorkList(Temp.Val);
3942 case ISD::SETULE: // X <=u Y --> X == 0 | Y == 1 --> X^1 | Y
3943 case ISD::SETGE: // X >=s Y --> X == 0 | Y == 1 --> X^1 | Y
3944 Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, DAG.getConstant(1, MVT::i1));
3945 N0 = DAG.getNode(ISD::OR, MVT::i1, N1, Temp);
3946 AddToWorkList(Temp.Val);
3948 case ISD::SETUGE: // X >=u Y --> X == 1 | Y == 0 --> Y^1 | X
3949 case ISD::SETLE: // X <=s Y --> X == 1 | Y == 0 --> Y^1 | X
3950 Temp = DAG.getNode(ISD::XOR, MVT::i1, N1, DAG.getConstant(1, MVT::i1));
3951 N0 = DAG.getNode(ISD::OR, MVT::i1, N0, Temp);
3954 if (VT != MVT::i1) {
3955 AddToWorkList(N0.Val);
3956 // FIXME: If running after legalize, we probably can't do this.
3957 N0 = DAG.getNode(ISD::ZERO_EXTEND, VT, N0);
3962 // Could not fold it.
3966 /// BuildSDIVSequence - Given an ISD::SDIV node expressing a divide by constant,
3967 /// return a DAG expression to select that will generate the same value by
3968 /// multiplying by a magic number. See:
3969 /// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
3970 SDOperand DAGCombiner::BuildSDIV(SDNode *N) {
3971 std::vector<SDNode*> Built;
3972 SDOperand S = TLI.BuildSDIV(N, DAG, &Built);
3974 for (std::vector<SDNode*>::iterator ii = Built.begin(), ee = Built.end();
3980 /// BuildUDIVSequence - Given an ISD::UDIV node expressing a divide by constant,
3981 /// return a DAG expression to select that will generate the same value by
3982 /// multiplying by a magic number. See:
3983 /// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
3984 SDOperand DAGCombiner::BuildUDIV(SDNode *N) {
3985 std::vector<SDNode*> Built;
3986 SDOperand S = TLI.BuildUDIV(N, DAG, &Built);
3988 for (std::vector<SDNode*>::iterator ii = Built.begin(), ee = Built.end();
3994 /// FindBaseOffset - Return true if base is known not to alias with anything
3995 /// but itself. Provides base object and offset as results.
3996 static bool FindBaseOffset(SDOperand Ptr, SDOperand &Base, int64_t &Offset) {
3997 // Assume it is a primitive operation.
3998 Base = Ptr; Offset = 0;
4000 // If it's an adding a simple constant then integrate the offset.
4001 if (Base.getOpcode() == ISD::ADD) {
4002 if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Base.getOperand(1))) {
4003 Base = Base.getOperand(0);
4004 Offset += C->getValue();
4008 // If it's any of the following then it can't alias with anything but itself.
4009 return isa<FrameIndexSDNode>(Base) ||
4010 isa<ConstantPoolSDNode>(Base) ||
4011 isa<GlobalAddressSDNode>(Base);
4014 /// isAlias - Return true if there is any possibility that the two addresses
4016 bool DAGCombiner::isAlias(SDOperand Ptr1, int64_t Size1,
4017 const Value *SrcValue1, int SrcValueOffset1,
4018 SDOperand Ptr2, int64_t Size2,
4019 const Value *SrcValue2, int SrcValueOffset2)
4021 // If they are the same then they must be aliases.
4022 if (Ptr1 == Ptr2) return true;
4024 // Gather base node and offset information.
4025 SDOperand Base1, Base2;
4026 int64_t Offset1, Offset2;
4027 bool KnownBase1 = FindBaseOffset(Ptr1, Base1, Offset1);
4028 bool KnownBase2 = FindBaseOffset(Ptr2, Base2, Offset2);
4030 // If they have a same base address then...
4031 if (Base1 == Base2) {
4032 // Check to see if the addresses overlap.
4033 return!((Offset1 + Size1) <= Offset2 || (Offset2 + Size2) <= Offset1);
4036 // If we know both bases then they can't alias.
4037 if (KnownBase1 && KnownBase2) return false;
4039 if (CombinerGlobalAA) {
4040 // Use alias analysis information.
4041 int Overlap1 = Size1 + SrcValueOffset1 + Offset1;
4042 int Overlap2 = Size2 + SrcValueOffset2 + Offset2;
4043 AliasAnalysis::AliasResult AAResult =
4044 AA.alias(SrcValue1, Overlap1, SrcValue2, Overlap2);
4045 if (AAResult == AliasAnalysis::NoAlias)
4049 // Otherwise we have to assume they alias.
4053 /// FindAliasInfo - Extracts the relevant alias information from the memory
4054 /// node. Returns true if the operand was a load.
4055 bool DAGCombiner::FindAliasInfo(SDNode *N,
4056 SDOperand &Ptr, int64_t &Size,
4057 const Value *&SrcValue, int &SrcValueOffset) {
4058 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) {
4059 Ptr = LD->getBasePtr();
4060 Size = MVT::getSizeInBits(LD->getLoadedVT()) >> 3;
4061 SrcValue = LD->getSrcValue();
4062 SrcValueOffset = LD->getSrcValueOffset();
4064 } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) {
4065 Ptr = ST->getBasePtr();
4066 Size = MVT::getSizeInBits(ST->getStoredVT()) >> 3;
4067 SrcValue = ST->getSrcValue();
4068 SrcValueOffset = ST->getSrcValueOffset();
4070 assert(0 && "FindAliasInfo expected a memory operand");
4076 /// GatherAllAliases - Walk up chain skipping non-aliasing memory nodes,
4077 /// looking for aliasing nodes and adding them to the Aliases vector.
4078 void DAGCombiner::GatherAllAliases(SDNode *N, SDOperand OriginalChain,
4079 SmallVector<SDOperand, 8> &Aliases) {
4080 SmallVector<SDOperand, 8> Chains; // List of chains to visit.
4081 std::set<SDNode *> Visited; // Visited node set.
4083 // Get alias information for node.
4086 const Value *SrcValue;
4088 bool IsLoad = FindAliasInfo(N, Ptr, Size, SrcValue, SrcValueOffset);
4091 Chains.push_back(OriginalChain);
4093 // Look at each chain and determine if it is an alias. If so, add it to the
4094 // aliases list. If not, then continue up the chain looking for the next
4096 while (!Chains.empty()) {
4097 SDOperand Chain = Chains.back();
4100 // Don't bother if we've been before.
4101 if (Visited.find(Chain.Val) != Visited.end()) continue;
4102 Visited.insert(Chain.Val);
4104 switch (Chain.getOpcode()) {
4105 case ISD::EntryToken:
4106 // Entry token is ideal chain operand, but handled in FindBetterChain.
4111 // Get alias information for Chain.
4114 const Value *OpSrcValue;
4115 int OpSrcValueOffset;
4116 bool IsOpLoad = FindAliasInfo(Chain.Val, OpPtr, OpSize,
4117 OpSrcValue, OpSrcValueOffset);
4119 // If chain is alias then stop here.
4120 if (!(IsLoad && IsOpLoad) &&
4121 isAlias(Ptr, Size, SrcValue, SrcValueOffset,
4122 OpPtr, OpSize, OpSrcValue, OpSrcValueOffset)) {
4123 Aliases.push_back(Chain);
4125 // Look further up the chain.
4126 Chains.push_back(Chain.getOperand(0));
4127 // Clean up old chain.
4128 AddToWorkList(Chain.Val);
4133 case ISD::TokenFactor:
4134 // We have to check each of the operands of the token factor, so we queue
4135 // then up. Adding the operands to the queue (stack) in reverse order
4136 // maintains the original order and increases the likelihood that getNode
4137 // will find a matching token factor (CSE.)
4138 for (unsigned n = Chain.getNumOperands(); n;)
4139 Chains.push_back(Chain.getOperand(--n));
4140 // Eliminate the token factor if we can.
4141 AddToWorkList(Chain.Val);
4145 // For all other instructions we will just have to take what we can get.
4146 Aliases.push_back(Chain);
4152 /// FindBetterChain - Walk up chain skipping non-aliasing memory nodes, looking
4153 /// for a better chain (aliasing node.)
4154 SDOperand DAGCombiner::FindBetterChain(SDNode *N, SDOperand OldChain) {
4155 SmallVector<SDOperand, 8> Aliases; // Ops for replacing token factor.
4157 // Accumulate all the aliases to this node.
4158 GatherAllAliases(N, OldChain, Aliases);
4160 if (Aliases.size() == 0) {
4161 // If no operands then chain to entry token.
4162 return DAG.getEntryNode();
4163 } else if (Aliases.size() == 1) {
4164 // If a single operand then chain to it. We don't need to revisit it.
4168 // Construct a custom tailored token factor.
4169 SDOperand NewChain = DAG.getNode(ISD::TokenFactor, MVT::Other,
4170 &Aliases[0], Aliases.size());
4172 // Make sure the old chain gets cleaned up.
4173 if (NewChain != OldChain) AddToWorkList(OldChain.Val);
4178 // SelectionDAG::Combine - This is the entry point for the file.
4180 void SelectionDAG::Combine(bool RunningAfterLegalize, AliasAnalysis &AA) {
4181 /// run - This is the main entry point to this class.
4183 DAGCombiner(*this, AA).Run(RunningAfterLegalize);