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: make truncate see through SIGN_EXTEND and AND
26 // FIXME: divide by zero is currently left unfolded. do we want to turn this
28 // FIXME: select ne (select cc, 1, 0), 0, true, false -> select cc, true, false
30 //===----------------------------------------------------------------------===//
32 #define DEBUG_TYPE "dagcombine"
33 #include "llvm/ADT/Statistic.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/Visibility.h"
45 Statistic<> NodesCombined ("dagcombiner", "Number of dag nodes combined");
47 class VISIBILITY_HIDDEN DAGCombiner {
52 // Worklist of all of the nodes that need to be simplified.
53 std::vector<SDNode*> WorkList;
55 /// AddUsersToWorkList - When an instruction is simplified, add all users of
56 /// the instruction to the work lists because they might get more simplified
59 void AddUsersToWorkList(SDNode *N) {
60 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end();
62 WorkList.push_back(*UI);
65 /// removeFromWorkList - remove all instances of N from the worklist.
67 void removeFromWorkList(SDNode *N) {
68 WorkList.erase(std::remove(WorkList.begin(), WorkList.end(), N),
73 void AddToWorkList(SDNode *N) {
74 WorkList.push_back(N);
77 SDOperand CombineTo(SDNode *N, const std::vector<SDOperand> &To) {
79 DEBUG(std::cerr << "\nReplacing "; N->dump();
80 std::cerr << "\nWith: "; To[0].Val->dump(&DAG);
81 std::cerr << " and " << To.size()-1 << " other values\n");
82 std::vector<SDNode*> NowDead;
83 DAG.ReplaceAllUsesWith(N, To, &NowDead);
85 // Push the new nodes and any users onto the worklist
86 for (unsigned i = 0, e = To.size(); i != e; ++i) {
87 WorkList.push_back(To[i].Val);
88 AddUsersToWorkList(To[i].Val);
91 // Nodes can end up on the worklist more than once. Make sure we do
92 // not process a node that has been replaced.
93 removeFromWorkList(N);
94 for (unsigned i = 0, e = NowDead.size(); i != e; ++i)
95 removeFromWorkList(NowDead[i]);
97 // Finally, since the node is now dead, remove it from the graph.
99 return SDOperand(N, 0);
102 SDOperand CombineTo(SDNode *N, SDOperand Res) {
103 std::vector<SDOperand> To;
105 return CombineTo(N, To);
108 SDOperand CombineTo(SDNode *N, SDOperand Res0, SDOperand Res1) {
109 std::vector<SDOperand> To;
112 return CombineTo(N, To);
116 /// SimplifyDemandedBits - Check the specified integer node value to see if
117 /// it can be simplified or if things it uses can be simplified by bit
118 /// propagation. If so, return true.
119 bool SimplifyDemandedBits(SDOperand Op) {
120 TargetLowering::TargetLoweringOpt TLO(DAG);
121 uint64_t KnownZero, KnownOne;
122 uint64_t Demanded = MVT::getIntVTBitMask(Op.getValueType());
123 if (!TLI.SimplifyDemandedBits(Op, Demanded, KnownZero, KnownOne, TLO))
127 WorkList.push_back(Op.Val);
129 // Replace the old value with the new one.
131 DEBUG(std::cerr << "\nReplacing "; TLO.Old.Val->dump();
132 std::cerr << "\nWith: "; TLO.New.Val->dump(&DAG));
134 std::vector<SDNode*> NowDead;
135 DAG.ReplaceAllUsesOfValueWith(TLO.Old, TLO.New, NowDead);
137 // Push the new node and any (possibly new) users onto the worklist.
138 WorkList.push_back(TLO.New.Val);
139 AddUsersToWorkList(TLO.New.Val);
141 // Nodes can end up on the worklist more than once. Make sure we do
142 // not process a node that has been replaced.
143 for (unsigned i = 0, e = NowDead.size(); i != e; ++i)
144 removeFromWorkList(NowDead[i]);
146 // Finally, if the node is now dead, remove it from the graph. The node
147 // may not be dead if the replacement process recursively simplified to
148 // something else needing this node.
149 if (TLO.Old.Val->use_empty()) {
150 removeFromWorkList(TLO.Old.Val);
151 DAG.DeleteNode(TLO.Old.Val);
156 /// visit - call the node-specific routine that knows how to fold each
157 /// particular type of node.
158 SDOperand visit(SDNode *N);
160 // Visitation implementation - Implement dag node combining for different
161 // node types. The semantics are as follows:
163 // SDOperand.Val == 0 - No change was made
164 // SDOperand.Val == N - N was replaced, is dead, and is already handled.
165 // otherwise - N should be replaced by the returned Operand.
167 SDOperand visitTokenFactor(SDNode *N);
168 SDOperand visitADD(SDNode *N);
169 SDOperand visitSUB(SDNode *N);
170 SDOperand visitMUL(SDNode *N);
171 SDOperand visitSDIV(SDNode *N);
172 SDOperand visitUDIV(SDNode *N);
173 SDOperand visitSREM(SDNode *N);
174 SDOperand visitUREM(SDNode *N);
175 SDOperand visitMULHU(SDNode *N);
176 SDOperand visitMULHS(SDNode *N);
177 SDOperand visitAND(SDNode *N);
178 SDOperand visitOR(SDNode *N);
179 SDOperand visitXOR(SDNode *N);
180 SDOperand visitVBinOp(SDNode *N, ISD::NodeType IntOp, ISD::NodeType FPOp);
181 SDOperand visitSHL(SDNode *N);
182 SDOperand visitSRA(SDNode *N);
183 SDOperand visitSRL(SDNode *N);
184 SDOperand visitCTLZ(SDNode *N);
185 SDOperand visitCTTZ(SDNode *N);
186 SDOperand visitCTPOP(SDNode *N);
187 SDOperand visitSELECT(SDNode *N);
188 SDOperand visitSELECT_CC(SDNode *N);
189 SDOperand visitSETCC(SDNode *N);
190 SDOperand visitSIGN_EXTEND(SDNode *N);
191 SDOperand visitZERO_EXTEND(SDNode *N);
192 SDOperand visitANY_EXTEND(SDNode *N);
193 SDOperand visitSIGN_EXTEND_INREG(SDNode *N);
194 SDOperand visitTRUNCATE(SDNode *N);
195 SDOperand visitBIT_CONVERT(SDNode *N);
196 SDOperand visitVBIT_CONVERT(SDNode *N);
197 SDOperand visitFADD(SDNode *N);
198 SDOperand visitFSUB(SDNode *N);
199 SDOperand visitFMUL(SDNode *N);
200 SDOperand visitFDIV(SDNode *N);
201 SDOperand visitFREM(SDNode *N);
202 SDOperand visitFCOPYSIGN(SDNode *N);
203 SDOperand visitSINT_TO_FP(SDNode *N);
204 SDOperand visitUINT_TO_FP(SDNode *N);
205 SDOperand visitFP_TO_SINT(SDNode *N);
206 SDOperand visitFP_TO_UINT(SDNode *N);
207 SDOperand visitFP_ROUND(SDNode *N);
208 SDOperand visitFP_ROUND_INREG(SDNode *N);
209 SDOperand visitFP_EXTEND(SDNode *N);
210 SDOperand visitFNEG(SDNode *N);
211 SDOperand visitFABS(SDNode *N);
212 SDOperand visitBRCOND(SDNode *N);
213 SDOperand visitBR_CC(SDNode *N);
214 SDOperand visitLOAD(SDNode *N);
215 SDOperand visitXEXTLOAD(SDNode *N);
216 SDOperand visitSTORE(SDNode *N);
217 SDOperand visitINSERT_VECTOR_ELT(SDNode *N);
218 SDOperand visitVINSERT_VECTOR_ELT(SDNode *N);
219 SDOperand visitVBUILD_VECTOR(SDNode *N);
220 SDOperand visitVECTOR_SHUFFLE(SDNode *N);
221 SDOperand visitVVECTOR_SHUFFLE(SDNode *N);
223 SDOperand XformToShuffleWithZero(SDNode *N);
224 SDOperand ReassociateOps(unsigned Opc, SDOperand LHS, SDOperand RHS);
226 bool SimplifySelectOps(SDNode *SELECT, SDOperand LHS, SDOperand RHS);
227 SDOperand SimplifyBinOpWithSameOpcodeHands(SDNode *N);
228 SDOperand SimplifySelect(SDOperand N0, SDOperand N1, SDOperand N2);
229 SDOperand SimplifySelectCC(SDOperand N0, SDOperand N1, SDOperand N2,
230 SDOperand N3, ISD::CondCode CC);
231 SDOperand SimplifySetCC(MVT::ValueType VT, SDOperand N0, SDOperand N1,
232 ISD::CondCode Cond, bool foldBooleans = true);
233 SDOperand ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(SDNode *, MVT::ValueType);
234 SDOperand BuildSDIV(SDNode *N);
235 SDOperand BuildUDIV(SDNode *N);
237 DAGCombiner(SelectionDAG &D)
238 : DAG(D), TLI(D.getTargetLoweringInfo()), AfterLegalize(false) {}
240 /// Run - runs the dag combiner on all nodes in the work list
241 void Run(bool RunningAfterLegalize);
245 //===----------------------------------------------------------------------===//
246 // TargetLowering::DAGCombinerInfo implementation
247 //===----------------------------------------------------------------------===//
249 void TargetLowering::DAGCombinerInfo::AddToWorklist(SDNode *N) {
250 ((DAGCombiner*)DC)->AddToWorkList(N);
253 SDOperand TargetLowering::DAGCombinerInfo::
254 CombineTo(SDNode *N, const std::vector<SDOperand> &To) {
255 return ((DAGCombiner*)DC)->CombineTo(N, To);
258 SDOperand TargetLowering::DAGCombinerInfo::
259 CombineTo(SDNode *N, SDOperand Res) {
260 return ((DAGCombiner*)DC)->CombineTo(N, Res);
264 SDOperand TargetLowering::DAGCombinerInfo::
265 CombineTo(SDNode *N, SDOperand Res0, SDOperand Res1) {
266 return ((DAGCombiner*)DC)->CombineTo(N, Res0, Res1);
272 //===----------------------------------------------------------------------===//
275 // isSetCCEquivalent - Return true if this node is a setcc, or is a select_cc
276 // that selects between the values 1 and 0, making it equivalent to a setcc.
277 // Also, set the incoming LHS, RHS, and CC references to the appropriate
278 // nodes based on the type of node we are checking. This simplifies life a
279 // bit for the callers.
280 static bool isSetCCEquivalent(SDOperand N, SDOperand &LHS, SDOperand &RHS,
282 if (N.getOpcode() == ISD::SETCC) {
283 LHS = N.getOperand(0);
284 RHS = N.getOperand(1);
285 CC = N.getOperand(2);
288 if (N.getOpcode() == ISD::SELECT_CC &&
289 N.getOperand(2).getOpcode() == ISD::Constant &&
290 N.getOperand(3).getOpcode() == ISD::Constant &&
291 cast<ConstantSDNode>(N.getOperand(2))->getValue() == 1 &&
292 cast<ConstantSDNode>(N.getOperand(3))->isNullValue()) {
293 LHS = N.getOperand(0);
294 RHS = N.getOperand(1);
295 CC = N.getOperand(4);
301 // isOneUseSetCC - Return true if this is a SetCC-equivalent operation with only
302 // one use. If this is true, it allows the users to invert the operation for
303 // free when it is profitable to do so.
304 static bool isOneUseSetCC(SDOperand N) {
305 SDOperand N0, N1, N2;
306 if (isSetCCEquivalent(N, N0, N1, N2) && N.Val->hasOneUse())
311 // FIXME: This should probably go in the ISD class rather than being duplicated
313 static bool isCommutativeBinOp(unsigned Opcode) {
319 case ISD::XOR: return true;
320 default: return false; // FIXME: Need commutative info for user ops!
324 SDOperand DAGCombiner::ReassociateOps(unsigned Opc, SDOperand N0, SDOperand N1){
325 MVT::ValueType VT = N0.getValueType();
326 // reassoc. (op (op x, c1), y) -> (op (op x, y), c1) iff x+c1 has one use
327 // reassoc. (op (op x, c1), c2) -> (op x, (op c1, c2))
328 if (N0.getOpcode() == Opc && isa<ConstantSDNode>(N0.getOperand(1))) {
329 if (isa<ConstantSDNode>(N1)) {
330 SDOperand OpNode = DAG.getNode(Opc, VT, N0.getOperand(1), N1);
331 AddToWorkList(OpNode.Val);
332 return DAG.getNode(Opc, VT, OpNode, N0.getOperand(0));
333 } else if (N0.hasOneUse()) {
334 SDOperand OpNode = DAG.getNode(Opc, VT, N0.getOperand(0), N1);
335 AddToWorkList(OpNode.Val);
336 return DAG.getNode(Opc, VT, OpNode, N0.getOperand(1));
339 // reassoc. (op y, (op x, c1)) -> (op (op x, y), c1) iff x+c1 has one use
340 // reassoc. (op c2, (op x, c1)) -> (op x, (op c1, c2))
341 if (N1.getOpcode() == Opc && isa<ConstantSDNode>(N1.getOperand(1))) {
342 if (isa<ConstantSDNode>(N0)) {
343 SDOperand OpNode = DAG.getNode(Opc, VT, N1.getOperand(1), N0);
344 AddToWorkList(OpNode.Val);
345 return DAG.getNode(Opc, VT, OpNode, N1.getOperand(0));
346 } else if (N1.hasOneUse()) {
347 SDOperand OpNode = DAG.getNode(Opc, VT, N1.getOperand(0), N0);
348 AddToWorkList(OpNode.Val);
349 return DAG.getNode(Opc, VT, OpNode, N1.getOperand(1));
355 void DAGCombiner::Run(bool RunningAfterLegalize) {
356 // set the instance variable, so that the various visit routines may use it.
357 AfterLegalize = RunningAfterLegalize;
359 // Add all the dag nodes to the worklist.
360 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(),
361 E = DAG.allnodes_end(); I != E; ++I)
362 WorkList.push_back(I);
364 // Create a dummy node (which is not added to allnodes), that adds a reference
365 // to the root node, preventing it from being deleted, and tracking any
366 // changes of the root.
367 HandleSDNode Dummy(DAG.getRoot());
370 /// DagCombineInfo - Expose the DAG combiner to the target combiner impls.
371 TargetLowering::DAGCombinerInfo
372 DagCombineInfo(DAG, !RunningAfterLegalize, this);
374 // while the worklist isn't empty, inspect the node on the end of it and
375 // try and combine it.
376 while (!WorkList.empty()) {
377 SDNode *N = WorkList.back();
380 // If N has no uses, it is dead. Make sure to revisit all N's operands once
381 // N is deleted from the DAG, since they too may now be dead or may have a
382 // reduced number of uses, allowing other xforms.
383 if (N->use_empty() && N != &Dummy) {
384 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
385 WorkList.push_back(N->getOperand(i).Val);
387 removeFromWorkList(N);
392 SDOperand RV = visit(N);
394 // If nothing happened, try a target-specific DAG combine.
396 assert(N->getOpcode() != ISD::DELETED_NODE &&
397 "Node was deleted but visit returned NULL!");
398 if (N->getOpcode() >= ISD::BUILTIN_OP_END ||
399 TLI.hasTargetDAGCombine((ISD::NodeType)N->getOpcode()))
400 RV = TLI.PerformDAGCombine(N, DagCombineInfo);
405 // If we get back the same node we passed in, rather than a new node or
406 // zero, we know that the node must have defined multiple values and
407 // CombineTo was used. Since CombineTo takes care of the worklist
408 // mechanics for us, we have no work to do in this case.
410 assert(N->getOpcode() != ISD::DELETED_NODE &&
411 RV.Val->getOpcode() != ISD::DELETED_NODE &&
412 "Node was deleted but visit returned new node!");
414 DEBUG(std::cerr << "\nReplacing "; N->dump();
415 std::cerr << "\nWith: "; RV.Val->dump(&DAG);
417 std::vector<SDNode*> NowDead;
418 DAG.ReplaceAllUsesWith(N, std::vector<SDOperand>(1, RV), &NowDead);
420 // Push the new node and any users onto the worklist
421 WorkList.push_back(RV.Val);
422 AddUsersToWorkList(RV.Val);
424 // Nodes can end up on the worklist more than once. Make sure we do
425 // not process a node that has been replaced.
426 removeFromWorkList(N);
427 for (unsigned i = 0, e = NowDead.size(); i != e; ++i)
428 removeFromWorkList(NowDead[i]);
430 // Finally, since the node is now dead, remove it from the graph.
436 // If the root changed (e.g. it was a dead load, update the root).
437 DAG.setRoot(Dummy.getValue());
440 SDOperand DAGCombiner::visit(SDNode *N) {
441 switch(N->getOpcode()) {
443 case ISD::TokenFactor: return visitTokenFactor(N);
444 case ISD::ADD: return visitADD(N);
445 case ISD::SUB: return visitSUB(N);
446 case ISD::MUL: return visitMUL(N);
447 case ISD::SDIV: return visitSDIV(N);
448 case ISD::UDIV: return visitUDIV(N);
449 case ISD::SREM: return visitSREM(N);
450 case ISD::UREM: return visitUREM(N);
451 case ISD::MULHU: return visitMULHU(N);
452 case ISD::MULHS: return visitMULHS(N);
453 case ISD::AND: return visitAND(N);
454 case ISD::OR: return visitOR(N);
455 case ISD::XOR: return visitXOR(N);
456 case ISD::SHL: return visitSHL(N);
457 case ISD::SRA: return visitSRA(N);
458 case ISD::SRL: return visitSRL(N);
459 case ISD::CTLZ: return visitCTLZ(N);
460 case ISD::CTTZ: return visitCTTZ(N);
461 case ISD::CTPOP: return visitCTPOP(N);
462 case ISD::SELECT: return visitSELECT(N);
463 case ISD::SELECT_CC: return visitSELECT_CC(N);
464 case ISD::SETCC: return visitSETCC(N);
465 case ISD::SIGN_EXTEND: return visitSIGN_EXTEND(N);
466 case ISD::ZERO_EXTEND: return visitZERO_EXTEND(N);
467 case ISD::ANY_EXTEND: return visitANY_EXTEND(N);
468 case ISD::SIGN_EXTEND_INREG: return visitSIGN_EXTEND_INREG(N);
469 case ISD::TRUNCATE: return visitTRUNCATE(N);
470 case ISD::BIT_CONVERT: return visitBIT_CONVERT(N);
471 case ISD::VBIT_CONVERT: return visitVBIT_CONVERT(N);
472 case ISD::FADD: return visitFADD(N);
473 case ISD::FSUB: return visitFSUB(N);
474 case ISD::FMUL: return visitFMUL(N);
475 case ISD::FDIV: return visitFDIV(N);
476 case ISD::FREM: return visitFREM(N);
477 case ISD::FCOPYSIGN: return visitFCOPYSIGN(N);
478 case ISD::SINT_TO_FP: return visitSINT_TO_FP(N);
479 case ISD::UINT_TO_FP: return visitUINT_TO_FP(N);
480 case ISD::FP_TO_SINT: return visitFP_TO_SINT(N);
481 case ISD::FP_TO_UINT: return visitFP_TO_UINT(N);
482 case ISD::FP_ROUND: return visitFP_ROUND(N);
483 case ISD::FP_ROUND_INREG: return visitFP_ROUND_INREG(N);
484 case ISD::FP_EXTEND: return visitFP_EXTEND(N);
485 case ISD::FNEG: return visitFNEG(N);
486 case ISD::FABS: return visitFABS(N);
487 case ISD::BRCOND: return visitBRCOND(N);
488 case ISD::BR_CC: return visitBR_CC(N);
489 case ISD::LOAD: return visitLOAD(N);
492 case ISD::ZEXTLOAD: return visitXEXTLOAD(N);
493 case ISD::STORE: return visitSTORE(N);
494 case ISD::INSERT_VECTOR_ELT: return visitINSERT_VECTOR_ELT(N);
495 case ISD::VINSERT_VECTOR_ELT: return visitVINSERT_VECTOR_ELT(N);
496 case ISD::VBUILD_VECTOR: return visitVBUILD_VECTOR(N);
497 case ISD::VECTOR_SHUFFLE: return visitVECTOR_SHUFFLE(N);
498 case ISD::VVECTOR_SHUFFLE: return visitVVECTOR_SHUFFLE(N);
499 case ISD::VADD: return visitVBinOp(N, ISD::ADD , ISD::FADD);
500 case ISD::VSUB: return visitVBinOp(N, ISD::SUB , ISD::FSUB);
501 case ISD::VMUL: return visitVBinOp(N, ISD::MUL , ISD::FMUL);
502 case ISD::VSDIV: return visitVBinOp(N, ISD::SDIV, ISD::FDIV);
503 case ISD::VUDIV: return visitVBinOp(N, ISD::UDIV, ISD::UDIV);
504 case ISD::VAND: return visitVBinOp(N, ISD::AND , ISD::AND);
505 case ISD::VOR: return visitVBinOp(N, ISD::OR , ISD::OR);
506 case ISD::VXOR: return visitVBinOp(N, ISD::XOR , ISD::XOR);
511 SDOperand DAGCombiner::visitTokenFactor(SDNode *N) {
512 std::vector<SDOperand> Ops;
513 bool Changed = false;
515 // If the token factor has two operands and one is the entry token, replace
516 // the token factor with the other operand.
517 if (N->getNumOperands() == 2) {
518 if (N->getOperand(0).getOpcode() == ISD::EntryToken ||
519 N->getOperand(0) == N->getOperand(1))
520 return N->getOperand(1);
521 if (N->getOperand(1).getOpcode() == ISD::EntryToken)
522 return N->getOperand(0);
525 // fold (tokenfactor (tokenfactor)) -> tokenfactor
526 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
527 SDOperand Op = N->getOperand(i);
528 if (Op.getOpcode() == ISD::TokenFactor && Op.hasOneUse()) {
529 AddToWorkList(Op.Val); // Remove dead node.
531 for (unsigned j = 0, e = Op.getNumOperands(); j != e; ++j)
532 Ops.push_back(Op.getOperand(j));
533 } else if (i == 0 || N->getOperand(i) != N->getOperand(i-1)) {
536 // Deleted an operand that was the same as the last one.
541 return DAG.getNode(ISD::TokenFactor, MVT::Other, Ops);
545 SDOperand DAGCombiner::visitADD(SDNode *N) {
546 SDOperand N0 = N->getOperand(0);
547 SDOperand N1 = N->getOperand(1);
548 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
549 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
550 MVT::ValueType VT = N0.getValueType();
552 // fold (add c1, c2) -> c1+c2
554 return DAG.getNode(ISD::ADD, VT, N0, N1);
555 // canonicalize constant to RHS
557 return DAG.getNode(ISD::ADD, VT, N1, N0);
558 // fold (add x, 0) -> x
559 if (N1C && N1C->isNullValue())
561 // fold ((c1-A)+c2) -> (c1+c2)-A
562 if (N1C && N0.getOpcode() == ISD::SUB)
563 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getOperand(0)))
564 return DAG.getNode(ISD::SUB, VT,
565 DAG.getConstant(N1C->getValue()+N0C->getValue(), VT),
568 SDOperand RADD = ReassociateOps(ISD::ADD, N0, N1);
571 // fold ((0-A) + B) -> B-A
572 if (N0.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N0.getOperand(0)) &&
573 cast<ConstantSDNode>(N0.getOperand(0))->isNullValue())
574 return DAG.getNode(ISD::SUB, VT, N1, N0.getOperand(1));
575 // fold (A + (0-B)) -> A-B
576 if (N1.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N1.getOperand(0)) &&
577 cast<ConstantSDNode>(N1.getOperand(0))->isNullValue())
578 return DAG.getNode(ISD::SUB, VT, N0, N1.getOperand(1));
579 // fold (A+(B-A)) -> B
580 if (N1.getOpcode() == ISD::SUB && N0 == N1.getOperand(1))
581 return N1.getOperand(0);
583 if (!MVT::isVector(VT) && SimplifyDemandedBits(SDOperand(N, 0)))
584 return SDOperand(N, 0);
586 // fold (a+b) -> (a|b) iff a and b share no bits.
587 if (MVT::isInteger(VT) && !MVT::isVector(VT)) {
588 uint64_t LHSZero, LHSOne;
589 uint64_t RHSZero, RHSOne;
590 uint64_t Mask = MVT::getIntVTBitMask(VT);
591 TLI.ComputeMaskedBits(N0, Mask, LHSZero, LHSOne);
593 TLI.ComputeMaskedBits(N1, Mask, RHSZero, RHSOne);
595 // If all possibly-set bits on the LHS are clear on the RHS, return an OR.
596 // If all possibly-set bits on the RHS are clear on the LHS, return an OR.
597 if ((RHSZero & (~LHSZero & Mask)) == (~LHSZero & Mask) ||
598 (LHSZero & (~RHSZero & Mask)) == (~RHSZero & Mask))
599 return DAG.getNode(ISD::OR, VT, N0, N1);
606 SDOperand DAGCombiner::visitSUB(SDNode *N) {
607 SDOperand N0 = N->getOperand(0);
608 SDOperand N1 = N->getOperand(1);
609 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val);
610 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
611 MVT::ValueType VT = N0.getValueType();
613 // fold (sub x, x) -> 0
615 return DAG.getConstant(0, N->getValueType(0));
616 // fold (sub c1, c2) -> c1-c2
618 return DAG.getNode(ISD::SUB, VT, N0, N1);
619 // fold (sub x, c) -> (add x, -c)
621 return DAG.getNode(ISD::ADD, VT, N0, DAG.getConstant(-N1C->getValue(), VT));
623 if (N0.getOpcode() == ISD::ADD && N0.getOperand(0) == N1)
624 return N0.getOperand(1);
626 if (N0.getOpcode() == ISD::ADD && N0.getOperand(1) == N1)
627 return N0.getOperand(0);
631 SDOperand DAGCombiner::visitMUL(SDNode *N) {
632 SDOperand N0 = N->getOperand(0);
633 SDOperand N1 = N->getOperand(1);
634 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
635 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
636 MVT::ValueType VT = N0.getValueType();
638 // fold (mul c1, c2) -> c1*c2
640 return DAG.getNode(ISD::MUL, VT, N0, N1);
641 // canonicalize constant to RHS
643 return DAG.getNode(ISD::MUL, VT, N1, N0);
644 // fold (mul x, 0) -> 0
645 if (N1C && N1C->isNullValue())
647 // fold (mul x, -1) -> 0-x
648 if (N1C && N1C->isAllOnesValue())
649 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), N0);
650 // fold (mul x, (1 << c)) -> x << c
651 if (N1C && isPowerOf2_64(N1C->getValue()))
652 return DAG.getNode(ISD::SHL, VT, N0,
653 DAG.getConstant(Log2_64(N1C->getValue()),
654 TLI.getShiftAmountTy()));
655 // fold (mul x, -(1 << c)) -> -(x << c) or (-x) << c
656 if (N1C && isPowerOf2_64(-N1C->getSignExtended())) {
657 // FIXME: If the input is something that is easily negated (e.g. a
658 // single-use add), we should put the negate there.
659 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT),
660 DAG.getNode(ISD::SHL, VT, N0,
661 DAG.getConstant(Log2_64(-N1C->getSignExtended()),
662 TLI.getShiftAmountTy())));
665 // (mul (shl X, c1), c2) -> (mul X, c2 << c1)
666 if (N1C && N0.getOpcode() == ISD::SHL &&
667 isa<ConstantSDNode>(N0.getOperand(1))) {
668 SDOperand C3 = DAG.getNode(ISD::SHL, VT, N1, N0.getOperand(1));
669 AddToWorkList(C3.Val);
670 return DAG.getNode(ISD::MUL, VT, N0.getOperand(0), C3);
673 // Change (mul (shl X, C), Y) -> (shl (mul X, Y), C) when the shift has one
676 SDOperand Sh(0,0), Y(0,0);
677 // Check for both (mul (shl X, C), Y) and (mul Y, (shl X, C)).
678 if (N0.getOpcode() == ISD::SHL && isa<ConstantSDNode>(N0.getOperand(1)) &&
679 N0.Val->hasOneUse()) {
681 } else if (N1.getOpcode() == ISD::SHL &&
682 isa<ConstantSDNode>(N1.getOperand(1)) && N1.Val->hasOneUse()) {
686 SDOperand Mul = DAG.getNode(ISD::MUL, VT, Sh.getOperand(0), Y);
687 return DAG.getNode(ISD::SHL, VT, Mul, Sh.getOperand(1));
690 // fold (mul (add x, c1), c2) -> (add (mul x, c2), c1*c2)
691 if (N1C && N0.getOpcode() == ISD::ADD && N0.Val->hasOneUse() &&
692 isa<ConstantSDNode>(N0.getOperand(1))) {
693 return DAG.getNode(ISD::ADD, VT,
694 DAG.getNode(ISD::MUL, VT, N0.getOperand(0), N1),
695 DAG.getNode(ISD::MUL, VT, N0.getOperand(1), N1));
699 SDOperand RMUL = ReassociateOps(ISD::MUL, N0, N1);
705 SDOperand DAGCombiner::visitSDIV(SDNode *N) {
706 SDOperand N0 = N->getOperand(0);
707 SDOperand N1 = N->getOperand(1);
708 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val);
709 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
710 MVT::ValueType VT = N->getValueType(0);
712 // fold (sdiv c1, c2) -> c1/c2
713 if (N0C && N1C && !N1C->isNullValue())
714 return DAG.getNode(ISD::SDIV, VT, N0, N1);
715 // fold (sdiv X, 1) -> X
716 if (N1C && N1C->getSignExtended() == 1LL)
718 // fold (sdiv X, -1) -> 0-X
719 if (N1C && N1C->isAllOnesValue())
720 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), N0);
721 // If we know the sign bits of both operands are zero, strength reduce to a
722 // udiv instead. Handles (X&15) /s 4 -> X&15 >> 2
723 uint64_t SignBit = 1ULL << (MVT::getSizeInBits(VT)-1);
724 if (TLI.MaskedValueIsZero(N1, SignBit) &&
725 TLI.MaskedValueIsZero(N0, SignBit))
726 return DAG.getNode(ISD::UDIV, N1.getValueType(), N0, N1);
727 // fold (sdiv X, pow2) -> simple ops after legalize
728 if (N1C && N1C->getValue() && !TLI.isIntDivCheap() &&
729 (isPowerOf2_64(N1C->getSignExtended()) ||
730 isPowerOf2_64(-N1C->getSignExtended()))) {
731 // If dividing by powers of two is cheap, then don't perform the following
733 if (TLI.isPow2DivCheap())
735 int64_t pow2 = N1C->getSignExtended();
736 int64_t abs2 = pow2 > 0 ? pow2 : -pow2;
737 unsigned lg2 = Log2_64(abs2);
738 // Splat the sign bit into the register
739 SDOperand SGN = DAG.getNode(ISD::SRA, VT, N0,
740 DAG.getConstant(MVT::getSizeInBits(VT)-1,
741 TLI.getShiftAmountTy()));
742 AddToWorkList(SGN.Val);
743 // Add (N0 < 0) ? abs2 - 1 : 0;
744 SDOperand SRL = DAG.getNode(ISD::SRL, VT, SGN,
745 DAG.getConstant(MVT::getSizeInBits(VT)-lg2,
746 TLI.getShiftAmountTy()));
747 SDOperand ADD = DAG.getNode(ISD::ADD, VT, N0, SRL);
748 AddToWorkList(SRL.Val);
749 AddToWorkList(ADD.Val); // Divide by pow2
750 SDOperand SRA = DAG.getNode(ISD::SRA, VT, ADD,
751 DAG.getConstant(lg2, TLI.getShiftAmountTy()));
752 // If we're dividing by a positive value, we're done. Otherwise, we must
753 // negate the result.
756 AddToWorkList(SRA.Val);
757 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), SRA);
759 // if integer divide is expensive and we satisfy the requirements, emit an
760 // alternate sequence.
761 if (N1C && (N1C->getSignExtended() < -1 || N1C->getSignExtended() > 1) &&
762 !TLI.isIntDivCheap()) {
763 SDOperand Op = BuildSDIV(N);
764 if (Op.Val) return Op;
769 SDOperand DAGCombiner::visitUDIV(SDNode *N) {
770 SDOperand N0 = N->getOperand(0);
771 SDOperand N1 = N->getOperand(1);
772 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val);
773 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
774 MVT::ValueType VT = N->getValueType(0);
776 // fold (udiv c1, c2) -> c1/c2
777 if (N0C && N1C && !N1C->isNullValue())
778 return DAG.getNode(ISD::UDIV, VT, N0, N1);
779 // fold (udiv x, (1 << c)) -> x >>u c
780 if (N1C && isPowerOf2_64(N1C->getValue()))
781 return DAG.getNode(ISD::SRL, VT, N0,
782 DAG.getConstant(Log2_64(N1C->getValue()),
783 TLI.getShiftAmountTy()));
784 // fold (udiv x, (shl c, y)) -> x >>u (log2(c)+y) iff c is power of 2
785 if (N1.getOpcode() == ISD::SHL) {
786 if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) {
787 if (isPowerOf2_64(SHC->getValue())) {
788 MVT::ValueType ADDVT = N1.getOperand(1).getValueType();
789 SDOperand Add = DAG.getNode(ISD::ADD, ADDVT, N1.getOperand(1),
790 DAG.getConstant(Log2_64(SHC->getValue()),
792 AddToWorkList(Add.Val);
793 return DAG.getNode(ISD::SRL, VT, N0, Add);
797 // fold (udiv x, c) -> alternate
798 if (N1C && N1C->getValue() && !TLI.isIntDivCheap()) {
799 SDOperand Op = BuildUDIV(N);
800 if (Op.Val) return Op;
805 SDOperand DAGCombiner::visitSREM(SDNode *N) {
806 SDOperand N0 = N->getOperand(0);
807 SDOperand N1 = N->getOperand(1);
808 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
809 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
810 MVT::ValueType VT = N->getValueType(0);
812 // fold (srem c1, c2) -> c1%c2
813 if (N0C && N1C && !N1C->isNullValue())
814 return DAG.getNode(ISD::SREM, VT, N0, N1);
815 // If we know the sign bits of both operands are zero, strength reduce to a
816 // urem instead. Handles (X & 0x0FFFFFFF) %s 16 -> X&15
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::UREM, VT, N0, N1);
824 SDOperand DAGCombiner::visitUREM(SDNode *N) {
825 SDOperand N0 = N->getOperand(0);
826 SDOperand N1 = N->getOperand(1);
827 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
828 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
829 MVT::ValueType VT = N->getValueType(0);
831 // fold (urem c1, c2) -> c1%c2
832 if (N0C && N1C && !N1C->isNullValue())
833 return DAG.getNode(ISD::UREM, VT, N0, N1);
834 // fold (urem x, pow2) -> (and x, pow2-1)
835 if (N1C && !N1C->isNullValue() && isPowerOf2_64(N1C->getValue()))
836 return DAG.getNode(ISD::AND, VT, N0, DAG.getConstant(N1C->getValue()-1,VT));
837 // fold (urem x, (shl pow2, y)) -> (and x, (add (shl pow2, y), -1))
838 if (N1.getOpcode() == ISD::SHL) {
839 if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) {
840 if (isPowerOf2_64(SHC->getValue())) {
841 SDOperand Add = DAG.getNode(ISD::ADD, VT, N1,DAG.getConstant(~0ULL,VT));
842 AddToWorkList(Add.Val);
843 return DAG.getNode(ISD::AND, VT, N0, Add);
850 SDOperand DAGCombiner::visitMULHS(SDNode *N) {
851 SDOperand N0 = N->getOperand(0);
852 SDOperand N1 = N->getOperand(1);
853 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
855 // fold (mulhs x, 0) -> 0
856 if (N1C && N1C->isNullValue())
858 // fold (mulhs x, 1) -> (sra x, size(x)-1)
859 if (N1C && N1C->getValue() == 1)
860 return DAG.getNode(ISD::SRA, N0.getValueType(), N0,
861 DAG.getConstant(MVT::getSizeInBits(N0.getValueType())-1,
862 TLI.getShiftAmountTy()));
866 SDOperand DAGCombiner::visitMULHU(SDNode *N) {
867 SDOperand N0 = N->getOperand(0);
868 SDOperand N1 = N->getOperand(1);
869 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
871 // fold (mulhu x, 0) -> 0
872 if (N1C && N1C->isNullValue())
874 // fold (mulhu x, 1) -> 0
875 if (N1C && N1C->getValue() == 1)
876 return DAG.getConstant(0, N0.getValueType());
880 /// SimplifyBinOpWithSameOpcodeHands - If this is a binary operator with
881 /// two operands of the same opcode, try to simplify it.
882 SDOperand DAGCombiner::SimplifyBinOpWithSameOpcodeHands(SDNode *N) {
883 SDOperand N0 = N->getOperand(0), N1 = N->getOperand(1);
884 MVT::ValueType VT = N0.getValueType();
885 assert(N0.getOpcode() == N1.getOpcode() && "Bad input!");
887 // For each of OP in AND/OR/XOR:
888 // fold (OP (zext x), (zext y)) -> (zext (OP x, y))
889 // fold (OP (sext x), (sext y)) -> (sext (OP x, y))
890 // fold (OP (aext x), (aext y)) -> (aext (OP x, y))
891 // fold (OP (trunc x), (trunc y)) -> (trunc (OP x, y))
892 if ((N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND||
893 N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::TRUNCATE) &&
894 N0.getOperand(0).getValueType() == N1.getOperand(0).getValueType()) {
895 SDOperand ORNode = DAG.getNode(N->getOpcode(),
896 N0.getOperand(0).getValueType(),
897 N0.getOperand(0), N1.getOperand(0));
898 AddToWorkList(ORNode.Val);
899 return DAG.getNode(N0.getOpcode(), VT, ORNode);
902 // For each of OP in SHL/SRL/SRA/AND...
903 // fold (and (OP x, z), (OP y, z)) -> (OP (and x, y), z)
904 // fold (or (OP x, z), (OP y, z)) -> (OP (or x, y), z)
905 // fold (xor (OP x, z), (OP y, z)) -> (OP (xor x, y), z)
906 if ((N0.getOpcode() == ISD::SHL || N0.getOpcode() == ISD::SRL ||
907 N0.getOpcode() == ISD::SRA || N0.getOpcode() == ISD::AND) &&
908 N0.getOperand(1) == N1.getOperand(1)) {
909 SDOperand ORNode = DAG.getNode(N->getOpcode(),
910 N0.getOperand(0).getValueType(),
911 N0.getOperand(0), N1.getOperand(0));
912 AddToWorkList(ORNode.Val);
913 return DAG.getNode(N0.getOpcode(), VT, ORNode, N0.getOperand(1));
919 SDOperand DAGCombiner::visitAND(SDNode *N) {
920 SDOperand N0 = N->getOperand(0);
921 SDOperand N1 = N->getOperand(1);
922 SDOperand LL, LR, RL, RR, CC0, CC1;
923 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
924 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
925 MVT::ValueType VT = N1.getValueType();
926 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
928 // fold (and c1, c2) -> c1&c2
930 return DAG.getNode(ISD::AND, VT, N0, N1);
931 // canonicalize constant to RHS
933 return DAG.getNode(ISD::AND, VT, N1, N0);
934 // fold (and x, -1) -> x
935 if (N1C && N1C->isAllOnesValue())
937 // if (and x, c) is known to be zero, return 0
938 if (N1C && TLI.MaskedValueIsZero(SDOperand(N, 0), MVT::getIntVTBitMask(VT)))
939 return DAG.getConstant(0, VT);
941 SDOperand RAND = ReassociateOps(ISD::AND, N0, N1);
944 // fold (and (or x, 0xFFFF), 0xFF) -> 0xFF
945 if (N1C && N0.getOpcode() == ISD::OR)
946 if (ConstantSDNode *ORI = dyn_cast<ConstantSDNode>(N0.getOperand(1)))
947 if ((ORI->getValue() & N1C->getValue()) == N1C->getValue())
949 // fold (and (any_ext V), c) -> (zero_ext V) if 'and' only clears top bits.
950 if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) {
951 unsigned InMask = MVT::getIntVTBitMask(N0.getOperand(0).getValueType());
952 if (TLI.MaskedValueIsZero(N0.getOperand(0),
953 ~N1C->getValue() & InMask)) {
954 SDOperand Zext = DAG.getNode(ISD::ZERO_EXTEND, N0.getValueType(),
957 // Replace uses of the AND with uses of the Zero extend node.
960 // We actually want to replace all uses of the any_extend with the
961 // zero_extend, to avoid duplicating things. This will later cause this
963 CombineTo(N0.Val, Zext);
964 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
967 // fold (and (setcc x), (setcc y)) -> (setcc (and x, y))
968 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){
969 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get();
970 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get();
972 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 &&
973 MVT::isInteger(LL.getValueType())) {
974 // fold (X == 0) & (Y == 0) -> (X|Y == 0)
975 if (cast<ConstantSDNode>(LR)->getValue() == 0 && Op1 == ISD::SETEQ) {
976 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL);
977 AddToWorkList(ORNode.Val);
978 return DAG.getSetCC(VT, ORNode, LR, Op1);
980 // fold (X == -1) & (Y == -1) -> (X&Y == -1)
981 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETEQ) {
982 SDOperand ANDNode = DAG.getNode(ISD::AND, LR.getValueType(), LL, RL);
983 AddToWorkList(ANDNode.Val);
984 return DAG.getSetCC(VT, ANDNode, LR, Op1);
986 // fold (X > -1) & (Y > -1) -> (X|Y > -1)
987 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETGT) {
988 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL);
989 AddToWorkList(ORNode.Val);
990 return DAG.getSetCC(VT, ORNode, LR, Op1);
993 // canonicalize equivalent to ll == rl
994 if (LL == RR && LR == RL) {
995 Op1 = ISD::getSetCCSwappedOperands(Op1);
998 if (LL == RL && LR == RR) {
999 bool isInteger = MVT::isInteger(LL.getValueType());
1000 ISD::CondCode Result = ISD::getSetCCAndOperation(Op0, Op1, isInteger);
1001 if (Result != ISD::SETCC_INVALID)
1002 return DAG.getSetCC(N0.getValueType(), LL, LR, Result);
1006 // Simplify: and (op x...), (op y...) -> (op (and x, y))
1007 if (N0.getOpcode() == N1.getOpcode()) {
1008 SDOperand Tmp = SimplifyBinOpWithSameOpcodeHands(N);
1009 if (Tmp.Val) return Tmp;
1012 // fold (and (sign_extend_inreg x, i16 to i32), 1) -> (and x, 1)
1013 // fold (and (sra)) -> (and (srl)) when possible.
1014 if (!MVT::isVector(VT) &&
1015 SimplifyDemandedBits(SDOperand(N, 0)))
1016 return SDOperand(N, 0);
1017 // fold (zext_inreg (extload x)) -> (zextload x)
1018 if (N0.getOpcode() == ISD::EXTLOAD) {
1019 MVT::ValueType EVT = cast<VTSDNode>(N0.getOperand(3))->getVT();
1020 // If we zero all the possible extended bits, then we can turn this into
1021 // a zextload if we are running before legalize or the operation is legal.
1022 if (TLI.MaskedValueIsZero(N1, ~0ULL << MVT::getSizeInBits(EVT)) &&
1023 (!AfterLegalize || TLI.isOperationLegal(ISD::ZEXTLOAD, EVT))) {
1024 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getOperand(0),
1025 N0.getOperand(1), N0.getOperand(2),
1028 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1));
1029 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1032 // fold (zext_inreg (sextload x)) -> (zextload x) iff load has one use
1033 if (N0.getOpcode() == ISD::SEXTLOAD && N0.hasOneUse()) {
1034 MVT::ValueType EVT = cast<VTSDNode>(N0.getOperand(3))->getVT();
1035 // If we zero all the possible extended bits, then we can turn this into
1036 // a zextload if we are running before legalize or the operation is legal.
1037 if (TLI.MaskedValueIsZero(N1, ~0ULL << MVT::getSizeInBits(EVT)) &&
1038 (!AfterLegalize || TLI.isOperationLegal(ISD::ZEXTLOAD, EVT))) {
1039 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getOperand(0),
1040 N0.getOperand(1), N0.getOperand(2),
1043 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1));
1044 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1048 // fold (and (load x), 255) -> (zextload x, i8)
1049 // fold (and (extload x, i16), 255) -> (zextload x, i8)
1051 (N0.getOpcode() == ISD::LOAD || N0.getOpcode() == ISD::EXTLOAD ||
1052 N0.getOpcode() == ISD::ZEXTLOAD) &&
1054 MVT::ValueType EVT, LoadedVT;
1055 if (N1C->getValue() == 255)
1057 else if (N1C->getValue() == 65535)
1059 else if (N1C->getValue() == ~0U)
1064 LoadedVT = N0.getOpcode() == ISD::LOAD ? VT :
1065 cast<VTSDNode>(N0.getOperand(3))->getVT();
1066 if (EVT != MVT::Other && LoadedVT > EVT &&
1067 (!AfterLegalize || TLI.isOperationLegal(ISD::ZEXTLOAD, EVT))) {
1068 MVT::ValueType PtrType = N0.getOperand(1).getValueType();
1069 // For big endian targets, we need to add an offset to the pointer to load
1070 // the correct bytes. For little endian systems, we merely need to read
1071 // fewer bytes from the same pointer.
1073 (MVT::getSizeInBits(LoadedVT) - MVT::getSizeInBits(EVT)) / 8;
1074 SDOperand NewPtr = N0.getOperand(1);
1075 if (!TLI.isLittleEndian())
1076 NewPtr = DAG.getNode(ISD::ADD, PtrType, NewPtr,
1077 DAG.getConstant(PtrOff, PtrType));
1078 AddToWorkList(NewPtr.Val);
1080 DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getOperand(0), NewPtr,
1081 N0.getOperand(2), EVT);
1083 CombineTo(N0.Val, Load, Load.getValue(1));
1084 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1091 SDOperand DAGCombiner::visitOR(SDNode *N) {
1092 SDOperand N0 = N->getOperand(0);
1093 SDOperand N1 = N->getOperand(1);
1094 SDOperand LL, LR, RL, RR, CC0, CC1;
1095 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1096 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1097 MVT::ValueType VT = N1.getValueType();
1098 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
1100 // fold (or c1, c2) -> c1|c2
1102 return DAG.getNode(ISD::OR, VT, N0, N1);
1103 // canonicalize constant to RHS
1105 return DAG.getNode(ISD::OR, VT, N1, N0);
1106 // fold (or x, 0) -> x
1107 if (N1C && N1C->isNullValue())
1109 // fold (or x, -1) -> -1
1110 if (N1C && N1C->isAllOnesValue())
1112 // fold (or x, c) -> c iff (x & ~c) == 0
1114 TLI.MaskedValueIsZero(N0,~N1C->getValue() & (~0ULL>>(64-OpSizeInBits))))
1117 SDOperand ROR = ReassociateOps(ISD::OR, N0, N1);
1120 // Canonicalize (or (and X, c1), c2) -> (and (or X, c2), c1|c2)
1121 if (N1C && N0.getOpcode() == ISD::AND && N0.Val->hasOneUse() &&
1122 isa<ConstantSDNode>(N0.getOperand(1))) {
1123 ConstantSDNode *C1 = cast<ConstantSDNode>(N0.getOperand(1));
1124 return DAG.getNode(ISD::AND, VT, DAG.getNode(ISD::OR, VT, N0.getOperand(0),
1126 DAG.getConstant(N1C->getValue() | C1->getValue(), VT));
1128 // fold (or (setcc x), (setcc y)) -> (setcc (or x, y))
1129 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){
1130 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get();
1131 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get();
1133 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 &&
1134 MVT::isInteger(LL.getValueType())) {
1135 // fold (X != 0) | (Y != 0) -> (X|Y != 0)
1136 // fold (X < 0) | (Y < 0) -> (X|Y < 0)
1137 if (cast<ConstantSDNode>(LR)->getValue() == 0 &&
1138 (Op1 == ISD::SETNE || Op1 == ISD::SETLT)) {
1139 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL);
1140 AddToWorkList(ORNode.Val);
1141 return DAG.getSetCC(VT, ORNode, LR, Op1);
1143 // fold (X != -1) | (Y != -1) -> (X&Y != -1)
1144 // fold (X > -1) | (Y > -1) -> (X&Y > -1)
1145 if (cast<ConstantSDNode>(LR)->isAllOnesValue() &&
1146 (Op1 == ISD::SETNE || Op1 == ISD::SETGT)) {
1147 SDOperand ANDNode = DAG.getNode(ISD::AND, LR.getValueType(), LL, RL);
1148 AddToWorkList(ANDNode.Val);
1149 return DAG.getSetCC(VT, ANDNode, LR, Op1);
1152 // canonicalize equivalent to ll == rl
1153 if (LL == RR && LR == RL) {
1154 Op1 = ISD::getSetCCSwappedOperands(Op1);
1157 if (LL == RL && LR == RR) {
1158 bool isInteger = MVT::isInteger(LL.getValueType());
1159 ISD::CondCode Result = ISD::getSetCCOrOperation(Op0, Op1, isInteger);
1160 if (Result != ISD::SETCC_INVALID)
1161 return DAG.getSetCC(N0.getValueType(), LL, LR, Result);
1165 // Simplify: or (op x...), (op y...) -> (op (or x, y))
1166 if (N0.getOpcode() == N1.getOpcode()) {
1167 SDOperand Tmp = SimplifyBinOpWithSameOpcodeHands(N);
1168 if (Tmp.Val) return Tmp;
1171 // canonicalize shl to left side in a shl/srl pair, to match rotate
1172 if (N0.getOpcode() == ISD::SRL && N1.getOpcode() == ISD::SHL)
1174 // check for rotl, rotr
1175 if (N0.getOpcode() == ISD::SHL && N1.getOpcode() == ISD::SRL &&
1176 N0.getOperand(0) == N1.getOperand(0) &&
1177 TLI.isOperationLegal(ISD::ROTL, VT) && TLI.isTypeLegal(VT)) {
1178 // fold (or (shl x, C1), (srl x, C2)) -> (rotl x, C1)
1179 if (N0.getOperand(1).getOpcode() == ISD::Constant &&
1180 N1.getOperand(1).getOpcode() == ISD::Constant) {
1181 uint64_t c1val = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
1182 uint64_t c2val = cast<ConstantSDNode>(N1.getOperand(1))->getValue();
1183 if ((c1val + c2val) == OpSizeInBits)
1184 return DAG.getNode(ISD::ROTL, VT, N0.getOperand(0), N0.getOperand(1));
1186 // fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotl x, y)
1187 if (N1.getOperand(1).getOpcode() == ISD::SUB &&
1188 N0.getOperand(1) == N1.getOperand(1).getOperand(1))
1189 if (ConstantSDNode *SUBC =
1190 dyn_cast<ConstantSDNode>(N1.getOperand(1).getOperand(0)))
1191 if (SUBC->getValue() == OpSizeInBits)
1192 return DAG.getNode(ISD::ROTL, VT, N0.getOperand(0), N0.getOperand(1));
1193 // fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotr x, y)
1194 if (N0.getOperand(1).getOpcode() == ISD::SUB &&
1195 N1.getOperand(1) == N0.getOperand(1).getOperand(1))
1196 if (ConstantSDNode *SUBC =
1197 dyn_cast<ConstantSDNode>(N0.getOperand(1).getOperand(0)))
1198 if (SUBC->getValue() == OpSizeInBits) {
1199 if (TLI.isOperationLegal(ISD::ROTR, VT) && TLI.isTypeLegal(VT))
1200 return DAG.getNode(ISD::ROTR, VT, N0.getOperand(0),
1203 return DAG.getNode(ISD::ROTL, VT, N0.getOperand(0),
1210 SDOperand DAGCombiner::visitXOR(SDNode *N) {
1211 SDOperand N0 = N->getOperand(0);
1212 SDOperand N1 = N->getOperand(1);
1213 SDOperand LHS, RHS, CC;
1214 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1215 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1216 MVT::ValueType VT = N0.getValueType();
1218 // fold (xor c1, c2) -> c1^c2
1220 return DAG.getNode(ISD::XOR, VT, N0, N1);
1221 // canonicalize constant to RHS
1223 return DAG.getNode(ISD::XOR, VT, N1, N0);
1224 // fold (xor x, 0) -> x
1225 if (N1C && N1C->isNullValue())
1228 SDOperand RXOR = ReassociateOps(ISD::XOR, N0, N1);
1231 // fold !(x cc y) -> (x !cc y)
1232 if (N1C && N1C->getValue() == 1 && isSetCCEquivalent(N0, LHS, RHS, CC)) {
1233 bool isInt = MVT::isInteger(LHS.getValueType());
1234 ISD::CondCode NotCC = ISD::getSetCCInverse(cast<CondCodeSDNode>(CC)->get(),
1236 if (N0.getOpcode() == ISD::SETCC)
1237 return DAG.getSetCC(VT, LHS, RHS, NotCC);
1238 if (N0.getOpcode() == ISD::SELECT_CC)
1239 return DAG.getSelectCC(LHS, RHS, N0.getOperand(2),N0.getOperand(3),NotCC);
1240 assert(0 && "Unhandled SetCC Equivalent!");
1243 // fold !(x or y) -> (!x and !y) iff x or y are setcc
1244 if (N1C && N1C->getValue() == 1 &&
1245 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) {
1246 SDOperand LHS = N0.getOperand(0), RHS = N0.getOperand(1);
1247 if (isOneUseSetCC(RHS) || isOneUseSetCC(LHS)) {
1248 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND;
1249 LHS = DAG.getNode(ISD::XOR, VT, LHS, N1); // RHS = ~LHS
1250 RHS = DAG.getNode(ISD::XOR, VT, RHS, N1); // RHS = ~RHS
1251 AddToWorkList(LHS.Val); AddToWorkList(RHS.Val);
1252 return DAG.getNode(NewOpcode, VT, LHS, RHS);
1255 // fold !(x or y) -> (!x and !y) iff x or y are constants
1256 if (N1C && N1C->isAllOnesValue() &&
1257 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) {
1258 SDOperand LHS = N0.getOperand(0), RHS = N0.getOperand(1);
1259 if (isa<ConstantSDNode>(RHS) || isa<ConstantSDNode>(LHS)) {
1260 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND;
1261 LHS = DAG.getNode(ISD::XOR, VT, LHS, N1); // RHS = ~LHS
1262 RHS = DAG.getNode(ISD::XOR, VT, RHS, N1); // RHS = ~RHS
1263 AddToWorkList(LHS.Val); AddToWorkList(RHS.Val);
1264 return DAG.getNode(NewOpcode, VT, LHS, RHS);
1267 // fold (xor (xor x, c1), c2) -> (xor x, c1^c2)
1268 if (N1C && N0.getOpcode() == ISD::XOR) {
1269 ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0));
1270 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
1272 return DAG.getNode(ISD::XOR, VT, N0.getOperand(1),
1273 DAG.getConstant(N1C->getValue()^N00C->getValue(), VT));
1275 return DAG.getNode(ISD::XOR, VT, N0.getOperand(0),
1276 DAG.getConstant(N1C->getValue()^N01C->getValue(), VT));
1278 // fold (xor x, x) -> 0
1280 if (!MVT::isVector(VT)) {
1281 return DAG.getConstant(0, VT);
1282 } else if (!AfterLegalize || TLI.isOperationLegal(ISD::BUILD_VECTOR, VT)) {
1283 // Produce a vector of zeros.
1284 SDOperand El = DAG.getConstant(0, MVT::getVectorBaseType(VT));
1285 std::vector<SDOperand> Ops(MVT::getVectorNumElements(VT), El);
1286 return DAG.getNode(ISD::BUILD_VECTOR, VT, Ops);
1290 // Simplify: xor (op x...), (op y...) -> (op (xor x, y))
1291 if (N0.getOpcode() == N1.getOpcode()) {
1292 SDOperand Tmp = SimplifyBinOpWithSameOpcodeHands(N);
1293 if (Tmp.Val) return Tmp;
1296 // Simplify the expression using non-local knowledge.
1297 if (!MVT::isVector(VT) &&
1298 SimplifyDemandedBits(SDOperand(N, 0)))
1299 return SDOperand(N, 0);
1304 SDOperand DAGCombiner::visitSHL(SDNode *N) {
1305 SDOperand N0 = N->getOperand(0);
1306 SDOperand N1 = N->getOperand(1);
1307 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1308 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1309 MVT::ValueType VT = N0.getValueType();
1310 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
1312 // fold (shl c1, c2) -> c1<<c2
1314 return DAG.getNode(ISD::SHL, VT, N0, N1);
1315 // fold (shl 0, x) -> 0
1316 if (N0C && N0C->isNullValue())
1318 // fold (shl x, c >= size(x)) -> undef
1319 if (N1C && N1C->getValue() >= OpSizeInBits)
1320 return DAG.getNode(ISD::UNDEF, VT);
1321 // fold (shl x, 0) -> x
1322 if (N1C && N1C->isNullValue())
1324 // if (shl x, c) is known to be zero, return 0
1325 if (TLI.MaskedValueIsZero(SDOperand(N, 0), MVT::getIntVTBitMask(VT)))
1326 return DAG.getConstant(0, VT);
1327 if (SimplifyDemandedBits(SDOperand(N, 0)))
1328 return SDOperand(N, 0);
1329 // fold (shl (shl x, c1), c2) -> 0 or (shl x, c1+c2)
1330 if (N1C && N0.getOpcode() == ISD::SHL &&
1331 N0.getOperand(1).getOpcode() == ISD::Constant) {
1332 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
1333 uint64_t c2 = N1C->getValue();
1334 if (c1 + c2 > OpSizeInBits)
1335 return DAG.getConstant(0, VT);
1336 return DAG.getNode(ISD::SHL, VT, N0.getOperand(0),
1337 DAG.getConstant(c1 + c2, N1.getValueType()));
1339 // fold (shl (srl x, c1), c2) -> (shl (and x, -1 << c1), c2-c1) or
1340 // (srl (and x, -1 << c1), c1-c2)
1341 if (N1C && N0.getOpcode() == ISD::SRL &&
1342 N0.getOperand(1).getOpcode() == ISD::Constant) {
1343 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
1344 uint64_t c2 = N1C->getValue();
1345 SDOperand Mask = DAG.getNode(ISD::AND, VT, N0.getOperand(0),
1346 DAG.getConstant(~0ULL << c1, VT));
1348 return DAG.getNode(ISD::SHL, VT, Mask,
1349 DAG.getConstant(c2-c1, N1.getValueType()));
1351 return DAG.getNode(ISD::SRL, VT, Mask,
1352 DAG.getConstant(c1-c2, N1.getValueType()));
1354 // fold (shl (sra x, c1), c1) -> (and x, -1 << c1)
1355 if (N1C && N0.getOpcode() == ISD::SRA && N1 == N0.getOperand(1))
1356 return DAG.getNode(ISD::AND, VT, N0.getOperand(0),
1357 DAG.getConstant(~0ULL << N1C->getValue(), VT));
1358 // fold (shl (add x, c1), c2) -> (add (shl x, c2), c1<<c2)
1359 if (N1C && N0.getOpcode() == ISD::ADD && N0.Val->hasOneUse() &&
1360 isa<ConstantSDNode>(N0.getOperand(1))) {
1361 return DAG.getNode(ISD::ADD, VT,
1362 DAG.getNode(ISD::SHL, VT, N0.getOperand(0), N1),
1363 DAG.getNode(ISD::SHL, VT, N0.getOperand(1), N1));
1368 SDOperand DAGCombiner::visitSRA(SDNode *N) {
1369 SDOperand N0 = N->getOperand(0);
1370 SDOperand N1 = N->getOperand(1);
1371 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1372 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1373 MVT::ValueType VT = N0.getValueType();
1375 // fold (sra c1, c2) -> c1>>c2
1377 return DAG.getNode(ISD::SRA, VT, N0, N1);
1378 // fold (sra 0, x) -> 0
1379 if (N0C && N0C->isNullValue())
1381 // fold (sra -1, x) -> -1
1382 if (N0C && N0C->isAllOnesValue())
1384 // fold (sra x, c >= size(x)) -> undef
1385 if (N1C && N1C->getValue() >= MVT::getSizeInBits(VT))
1386 return DAG.getNode(ISD::UNDEF, VT);
1387 // fold (sra x, 0) -> x
1388 if (N1C && N1C->isNullValue())
1390 // fold (sra (shl x, c1), c1) -> sext_inreg for some c1 and target supports
1392 if (N1C && N0.getOpcode() == ISD::SHL && N1 == N0.getOperand(1)) {
1393 unsigned LowBits = MVT::getSizeInBits(VT) - (unsigned)N1C->getValue();
1396 default: EVT = MVT::Other; break;
1397 case 1: EVT = MVT::i1; break;
1398 case 8: EVT = MVT::i8; break;
1399 case 16: EVT = MVT::i16; break;
1400 case 32: EVT = MVT::i32; break;
1402 if (EVT > MVT::Other && TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, EVT))
1403 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0),
1404 DAG.getValueType(EVT));
1407 // fold (sra (sra x, c1), c2) -> (sra x, c1+c2)
1408 if (N1C && N0.getOpcode() == ISD::SRA) {
1409 if (ConstantSDNode *C1 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
1410 unsigned Sum = N1C->getValue() + C1->getValue();
1411 if (Sum >= MVT::getSizeInBits(VT)) Sum = MVT::getSizeInBits(VT)-1;
1412 return DAG.getNode(ISD::SRA, VT, N0.getOperand(0),
1413 DAG.getConstant(Sum, N1C->getValueType(0)));
1417 // Simplify, based on bits shifted out of the LHS.
1418 if (N1C && SimplifyDemandedBits(SDOperand(N, 0)))
1419 return SDOperand(N, 0);
1422 // If the sign bit is known to be zero, switch this to a SRL.
1423 if (TLI.MaskedValueIsZero(N0, MVT::getIntVTSignBit(VT)))
1424 return DAG.getNode(ISD::SRL, VT, N0, N1);
1428 SDOperand DAGCombiner::visitSRL(SDNode *N) {
1429 SDOperand N0 = N->getOperand(0);
1430 SDOperand N1 = N->getOperand(1);
1431 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1432 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1433 MVT::ValueType VT = N0.getValueType();
1434 unsigned OpSizeInBits = MVT::getSizeInBits(VT);
1436 // fold (srl c1, c2) -> c1 >>u c2
1438 return DAG.getNode(ISD::SRL, VT, N0, N1);
1439 // fold (srl 0, x) -> 0
1440 if (N0C && N0C->isNullValue())
1442 // fold (srl x, c >= size(x)) -> undef
1443 if (N1C && N1C->getValue() >= OpSizeInBits)
1444 return DAG.getNode(ISD::UNDEF, VT);
1445 // fold (srl x, 0) -> x
1446 if (N1C && N1C->isNullValue())
1448 // if (srl x, c) is known to be zero, return 0
1449 if (N1C && TLI.MaskedValueIsZero(SDOperand(N, 0), ~0ULL >> (64-OpSizeInBits)))
1450 return DAG.getConstant(0, VT);
1451 // fold (srl (srl x, c1), c2) -> 0 or (srl x, c1+c2)
1452 if (N1C && N0.getOpcode() == ISD::SRL &&
1453 N0.getOperand(1).getOpcode() == ISD::Constant) {
1454 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
1455 uint64_t c2 = N1C->getValue();
1456 if (c1 + c2 > OpSizeInBits)
1457 return DAG.getConstant(0, VT);
1458 return DAG.getNode(ISD::SRL, VT, N0.getOperand(0),
1459 DAG.getConstant(c1 + c2, N1.getValueType()));
1462 // fold (srl (anyextend x), c) -> (anyextend (srl x, c))
1463 if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) {
1464 // Shifting in all undef bits?
1465 MVT::ValueType SmallVT = N0.getOperand(0).getValueType();
1466 if (N1C->getValue() >= MVT::getSizeInBits(SmallVT))
1467 return DAG.getNode(ISD::UNDEF, VT);
1469 SDOperand SmallShift = DAG.getNode(ISD::SRL, SmallVT, N0.getOperand(0), N1);
1470 AddToWorkList(SmallShift.Val);
1471 return DAG.getNode(ISD::ANY_EXTEND, VT, SmallShift);
1474 // fold (srl (ctlz x), "5") -> x iff x has one bit set (the low bit).
1475 if (N1C && N0.getOpcode() == ISD::CTLZ &&
1476 N1C->getValue() == Log2_32(MVT::getSizeInBits(VT))) {
1477 uint64_t KnownZero, KnownOne, Mask = MVT::getIntVTBitMask(VT);
1478 TLI.ComputeMaskedBits(N0.getOperand(0), Mask, KnownZero, KnownOne);
1480 // If any of the input bits are KnownOne, then the input couldn't be all
1481 // zeros, thus the result of the srl will always be zero.
1482 if (KnownOne) return DAG.getConstant(0, VT);
1484 // If all of the bits input the to ctlz node are known to be zero, then
1485 // the result of the ctlz is "32" and the result of the shift is one.
1486 uint64_t UnknownBits = ~KnownZero & Mask;
1487 if (UnknownBits == 0) return DAG.getConstant(1, VT);
1489 // Otherwise, check to see if there is exactly one bit input to the ctlz.
1490 if ((UnknownBits & (UnknownBits-1)) == 0) {
1491 // Okay, we know that only that the single bit specified by UnknownBits
1492 // could be set on input to the CTLZ node. If this bit is set, the SRL
1493 // will return 0, if it is clear, it returns 1. Change the CTLZ/SRL pair
1494 // to an SRL,XOR pair, which is likely to simplify more.
1495 unsigned ShAmt = CountTrailingZeros_64(UnknownBits);
1496 SDOperand Op = N0.getOperand(0);
1498 Op = DAG.getNode(ISD::SRL, VT, Op,
1499 DAG.getConstant(ShAmt, TLI.getShiftAmountTy()));
1500 AddToWorkList(Op.Val);
1502 return DAG.getNode(ISD::XOR, VT, Op, DAG.getConstant(1, VT));
1509 SDOperand DAGCombiner::visitCTLZ(SDNode *N) {
1510 SDOperand N0 = N->getOperand(0);
1511 MVT::ValueType VT = N->getValueType(0);
1513 // fold (ctlz c1) -> c2
1514 if (isa<ConstantSDNode>(N0))
1515 return DAG.getNode(ISD::CTLZ, VT, N0);
1519 SDOperand DAGCombiner::visitCTTZ(SDNode *N) {
1520 SDOperand N0 = N->getOperand(0);
1521 MVT::ValueType VT = N->getValueType(0);
1523 // fold (cttz c1) -> c2
1524 if (isa<ConstantSDNode>(N0))
1525 return DAG.getNode(ISD::CTTZ, VT, N0);
1529 SDOperand DAGCombiner::visitCTPOP(SDNode *N) {
1530 SDOperand N0 = N->getOperand(0);
1531 MVT::ValueType VT = N->getValueType(0);
1533 // fold (ctpop c1) -> c2
1534 if (isa<ConstantSDNode>(N0))
1535 return DAG.getNode(ISD::CTPOP, VT, N0);
1539 SDOperand DAGCombiner::visitSELECT(SDNode *N) {
1540 SDOperand N0 = N->getOperand(0);
1541 SDOperand N1 = N->getOperand(1);
1542 SDOperand N2 = N->getOperand(2);
1543 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1544 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1545 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2);
1546 MVT::ValueType VT = N->getValueType(0);
1548 // fold select C, X, X -> X
1551 // fold select true, X, Y -> X
1552 if (N0C && !N0C->isNullValue())
1554 // fold select false, X, Y -> Y
1555 if (N0C && N0C->isNullValue())
1557 // fold select C, 1, X -> C | X
1558 if (MVT::i1 == VT && N1C && N1C->getValue() == 1)
1559 return DAG.getNode(ISD::OR, VT, N0, N2);
1560 // fold select C, 0, X -> ~C & X
1561 // FIXME: this should check for C type == X type, not i1?
1562 if (MVT::i1 == VT && N1C && N1C->isNullValue()) {
1563 SDOperand XORNode = DAG.getNode(ISD::XOR, VT, N0, DAG.getConstant(1, VT));
1564 AddToWorkList(XORNode.Val);
1565 return DAG.getNode(ISD::AND, VT, XORNode, N2);
1567 // fold select C, X, 1 -> ~C | X
1568 if (MVT::i1 == VT && N2C && N2C->getValue() == 1) {
1569 SDOperand XORNode = DAG.getNode(ISD::XOR, VT, N0, DAG.getConstant(1, VT));
1570 AddToWorkList(XORNode.Val);
1571 return DAG.getNode(ISD::OR, VT, XORNode, N1);
1573 // fold select C, X, 0 -> C & X
1574 // FIXME: this should check for C type == X type, not i1?
1575 if (MVT::i1 == VT && N2C && N2C->isNullValue())
1576 return DAG.getNode(ISD::AND, VT, N0, N1);
1577 // fold X ? X : Y --> X ? 1 : Y --> X | Y
1578 if (MVT::i1 == VT && N0 == N1)
1579 return DAG.getNode(ISD::OR, VT, N0, N2);
1580 // fold X ? Y : X --> X ? Y : 0 --> X & Y
1581 if (MVT::i1 == VT && N0 == N2)
1582 return DAG.getNode(ISD::AND, VT, N0, N1);
1584 // If we can fold this based on the true/false value, do so.
1585 if (SimplifySelectOps(N, N1, N2))
1586 return SDOperand(N, 0); // Don't revisit N.
1588 // fold selects based on a setcc into other things, such as min/max/abs
1589 if (N0.getOpcode() == ISD::SETCC)
1591 // Check against MVT::Other for SELECT_CC, which is a workaround for targets
1592 // having to say they don't support SELECT_CC on every type the DAG knows
1593 // about, since there is no way to mark an opcode illegal at all value types
1594 if (TLI.isOperationLegal(ISD::SELECT_CC, MVT::Other))
1595 return DAG.getNode(ISD::SELECT_CC, VT, N0.getOperand(0), N0.getOperand(1),
1596 N1, N2, N0.getOperand(2));
1598 return SimplifySelect(N0, N1, N2);
1602 SDOperand DAGCombiner::visitSELECT_CC(SDNode *N) {
1603 SDOperand N0 = N->getOperand(0);
1604 SDOperand N1 = N->getOperand(1);
1605 SDOperand N2 = N->getOperand(2);
1606 SDOperand N3 = N->getOperand(3);
1607 SDOperand N4 = N->getOperand(4);
1608 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
1609 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
1610 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2);
1611 ISD::CondCode CC = cast<CondCodeSDNode>(N4)->get();
1613 // Determine if the condition we're dealing with is constant
1614 SDOperand SCC = SimplifySetCC(TLI.getSetCCResultTy(), N0, N1, CC, false);
1615 //ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.Val);
1617 // fold select_cc lhs, rhs, x, x, cc -> x
1621 // If we can fold this based on the true/false value, do so.
1622 if (SimplifySelectOps(N, N2, N3))
1623 return SDOperand(N, 0); // Don't revisit N.
1625 // fold select_cc into other things, such as min/max/abs
1626 return SimplifySelectCC(N0, N1, N2, N3, CC);
1629 SDOperand DAGCombiner::visitSETCC(SDNode *N) {
1630 return SimplifySetCC(N->getValueType(0), N->getOperand(0), N->getOperand(1),
1631 cast<CondCodeSDNode>(N->getOperand(2))->get());
1634 SDOperand DAGCombiner::visitSIGN_EXTEND(SDNode *N) {
1635 SDOperand N0 = N->getOperand(0);
1636 MVT::ValueType VT = N->getValueType(0);
1638 // fold (sext c1) -> c1
1639 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0))
1640 return DAG.getNode(ISD::SIGN_EXTEND, VT, N0);
1642 // fold (sext (sext x)) -> (sext x)
1643 // fold (sext (aext x)) -> (sext x)
1644 if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND)
1645 return DAG.getNode(ISD::SIGN_EXTEND, VT, N0.getOperand(0));
1647 // fold (sext (truncate x)) -> (sextinreg x) iff x size == sext size.
1648 if (N0.getOpcode() == ISD::TRUNCATE && N0.getOperand(0).getValueType() == VT&&
1650 TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, N0.getValueType())))
1651 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0),
1652 DAG.getValueType(N0.getValueType()));
1654 // fold (sext (load x)) -> (sext (truncate (sextload x)))
1655 if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse() &&
1656 (!AfterLegalize||TLI.isOperationLegal(ISD::SEXTLOAD, N0.getValueType()))){
1657 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0),
1658 N0.getOperand(1), N0.getOperand(2),
1660 CombineTo(N, ExtLoad);
1661 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
1662 ExtLoad.getValue(1));
1663 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1666 // fold (sext (sextload x)) -> (sext (truncate (sextload x)))
1667 // fold (sext ( extload x)) -> (sext (truncate (sextload x)))
1668 if ((N0.getOpcode() == ISD::SEXTLOAD || N0.getOpcode() == ISD::EXTLOAD) &&
1670 MVT::ValueType EVT = cast<VTSDNode>(N0.getOperand(3))->getVT();
1671 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0),
1672 N0.getOperand(1), N0.getOperand(2), EVT);
1673 CombineTo(N, ExtLoad);
1674 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
1675 ExtLoad.getValue(1));
1676 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1682 SDOperand DAGCombiner::visitZERO_EXTEND(SDNode *N) {
1683 SDOperand N0 = N->getOperand(0);
1684 MVT::ValueType VT = N->getValueType(0);
1686 // fold (zext c1) -> c1
1687 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0))
1688 return DAG.getNode(ISD::ZERO_EXTEND, VT, N0);
1689 // fold (zext (zext x)) -> (zext x)
1690 // fold (zext (aext x)) -> (zext x)
1691 if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND)
1692 return DAG.getNode(ISD::ZERO_EXTEND, VT, N0.getOperand(0));
1693 // fold (zext (truncate x)) -> (zextinreg x) iff x size == zext size.
1694 if (N0.getOpcode() == ISD::TRUNCATE && N0.getOperand(0).getValueType() == VT&&
1695 (!AfterLegalize || TLI.isOperationLegal(ISD::AND, N0.getValueType())))
1696 return DAG.getZeroExtendInReg(N0.getOperand(0), N0.getValueType());
1697 // fold (zext (load x)) -> (zext (truncate (zextload x)))
1698 if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse() &&
1699 (!AfterLegalize||TLI.isOperationLegal(ISD::ZEXTLOAD, N0.getValueType()))){
1700 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getOperand(0),
1701 N0.getOperand(1), N0.getOperand(2),
1703 CombineTo(N, ExtLoad);
1704 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
1705 ExtLoad.getValue(1));
1706 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1709 // fold (zext (zextload x)) -> (zext (truncate (zextload x)))
1710 // fold (zext ( extload x)) -> (zext (truncate (zextload x)))
1711 if ((N0.getOpcode() == ISD::ZEXTLOAD || N0.getOpcode() == ISD::EXTLOAD) &&
1713 MVT::ValueType EVT = cast<VTSDNode>(N0.getOperand(3))->getVT();
1714 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getOperand(0),
1715 N0.getOperand(1), N0.getOperand(2), EVT);
1716 CombineTo(N, ExtLoad);
1717 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
1718 ExtLoad.getValue(1));
1719 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1724 SDOperand DAGCombiner::visitANY_EXTEND(SDNode *N) {
1725 SDOperand N0 = N->getOperand(0);
1726 MVT::ValueType VT = N->getValueType(0);
1728 // fold (aext c1) -> c1
1729 if (isa<ConstantSDNode>(N0))
1730 return DAG.getNode(ISD::ANY_EXTEND, VT, N0);
1731 // fold (aext (aext x)) -> (aext x)
1732 // fold (aext (zext x)) -> (zext x)
1733 // fold (aext (sext x)) -> (sext x)
1734 if (N0.getOpcode() == ISD::ANY_EXTEND ||
1735 N0.getOpcode() == ISD::ZERO_EXTEND ||
1736 N0.getOpcode() == ISD::SIGN_EXTEND)
1737 return DAG.getNode(N0.getOpcode(), VT, N0.getOperand(0));
1739 // fold (aext (truncate x)) -> x iff x size == zext size.
1740 if (N0.getOpcode() == ISD::TRUNCATE && N0.getOperand(0).getValueType() == VT)
1741 return N0.getOperand(0);
1742 // fold (aext (load x)) -> (aext (truncate (extload x)))
1743 if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse() &&
1744 (!AfterLegalize||TLI.isOperationLegal(ISD::EXTLOAD, N0.getValueType()))) {
1745 SDOperand ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, VT, N0.getOperand(0),
1746 N0.getOperand(1), N0.getOperand(2),
1748 CombineTo(N, ExtLoad);
1749 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
1750 ExtLoad.getValue(1));
1751 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1754 // fold (aext (zextload x)) -> (aext (truncate (zextload x)))
1755 // fold (aext (sextload x)) -> (aext (truncate (sextload x)))
1756 // fold (aext ( extload x)) -> (aext (truncate (extload x)))
1757 if ((N0.getOpcode() == ISD::ZEXTLOAD || N0.getOpcode() == ISD::EXTLOAD ||
1758 N0.getOpcode() == ISD::SEXTLOAD) &&
1760 MVT::ValueType EVT = cast<VTSDNode>(N0.getOperand(3))->getVT();
1761 SDOperand ExtLoad = DAG.getExtLoad(N0.getOpcode(), VT, N0.getOperand(0),
1762 N0.getOperand(1), N0.getOperand(2), EVT);
1763 CombineTo(N, ExtLoad);
1764 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
1765 ExtLoad.getValue(1));
1766 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1772 SDOperand DAGCombiner::visitSIGN_EXTEND_INREG(SDNode *N) {
1773 SDOperand N0 = N->getOperand(0);
1774 SDOperand N1 = N->getOperand(1);
1775 MVT::ValueType VT = N->getValueType(0);
1776 MVT::ValueType EVT = cast<VTSDNode>(N1)->getVT();
1777 unsigned EVTBits = MVT::getSizeInBits(EVT);
1779 // fold (sext_in_reg c1) -> c1
1780 if (isa<ConstantSDNode>(N0) || N0.getOpcode() == ISD::UNDEF)
1781 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0, N1);
1783 // If the input is already sign extended, just drop the extension.
1784 if (TLI.ComputeNumSignBits(N0) >= MVT::getSizeInBits(VT)-EVTBits+1)
1787 // fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt2
1788 if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
1789 EVT < cast<VTSDNode>(N0.getOperand(1))->getVT()) {
1790 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0), N1);
1793 // fold (sext_in_reg x) -> (zext_in_reg x) if the sign bit is zero
1794 if (TLI.MaskedValueIsZero(N0, 1ULL << (EVTBits-1)))
1795 return DAG.getZeroExtendInReg(N0, EVT);
1797 // fold (sext_in_reg (srl X, 24), i8) -> sra X, 24
1798 // fold (sext_in_reg (srl X, 23), i8) -> sra X, 23 iff possible.
1799 // We already fold "(sext_in_reg (srl X, 25), i8) -> srl X, 25" above.
1800 if (N0.getOpcode() == ISD::SRL) {
1801 if (ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(N0.getOperand(1)))
1802 if (ShAmt->getValue()+EVTBits <= MVT::getSizeInBits(VT)) {
1803 // We can turn this into an SRA iff the input to the SRL is already sign
1805 unsigned InSignBits = TLI.ComputeNumSignBits(N0.getOperand(0));
1806 if (MVT::getSizeInBits(VT)-(ShAmt->getValue()+EVTBits) < InSignBits)
1807 return DAG.getNode(ISD::SRA, VT, N0.getOperand(0), N0.getOperand(1));
1811 // fold (sext_inreg (extload x)) -> (sextload x)
1812 if (N0.getOpcode() == ISD::EXTLOAD &&
1813 EVT == cast<VTSDNode>(N0.getOperand(3))->getVT() &&
1814 (!AfterLegalize || TLI.isOperationLegal(ISD::SEXTLOAD, EVT))) {
1815 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0),
1816 N0.getOperand(1), N0.getOperand(2),
1818 CombineTo(N, ExtLoad);
1819 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1));
1820 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1822 // fold (sext_inreg (zextload x)) -> (sextload x) iff load has one use
1823 if (N0.getOpcode() == ISD::ZEXTLOAD && N0.hasOneUse() &&
1824 EVT == cast<VTSDNode>(N0.getOperand(3))->getVT() &&
1825 (!AfterLegalize || TLI.isOperationLegal(ISD::SEXTLOAD, EVT))) {
1826 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0),
1827 N0.getOperand(1), N0.getOperand(2),
1829 CombineTo(N, ExtLoad);
1830 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1));
1831 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1836 SDOperand DAGCombiner::visitTRUNCATE(SDNode *N) {
1837 SDOperand N0 = N->getOperand(0);
1838 MVT::ValueType VT = N->getValueType(0);
1841 if (N0.getValueType() == N->getValueType(0))
1843 // fold (truncate c1) -> c1
1844 if (isa<ConstantSDNode>(N0))
1845 return DAG.getNode(ISD::TRUNCATE, VT, N0);
1846 // fold (truncate (truncate x)) -> (truncate x)
1847 if (N0.getOpcode() == ISD::TRUNCATE)
1848 return DAG.getNode(ISD::TRUNCATE, VT, N0.getOperand(0));
1849 // fold (truncate (ext x)) -> (ext x) or (truncate x) or x
1850 if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::SIGN_EXTEND||
1851 N0.getOpcode() == ISD::ANY_EXTEND) {
1852 if (N0.getValueType() < VT)
1853 // if the source is smaller than the dest, we still need an extend
1854 return DAG.getNode(N0.getOpcode(), VT, N0.getOperand(0));
1855 else if (N0.getValueType() > VT)
1856 // if the source is larger than the dest, than we just need the truncate
1857 return DAG.getNode(ISD::TRUNCATE, VT, N0.getOperand(0));
1859 // if the source and dest are the same type, we can drop both the extend
1861 return N0.getOperand(0);
1863 // fold (truncate (load x)) -> (smaller load x)
1864 if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse()) {
1865 assert(MVT::getSizeInBits(N0.getValueType()) > MVT::getSizeInBits(VT) &&
1866 "Cannot truncate to larger type!");
1867 MVT::ValueType PtrType = N0.getOperand(1).getValueType();
1868 // For big endian targets, we need to add an offset to the pointer to load
1869 // the correct bytes. For little endian systems, we merely need to read
1870 // fewer bytes from the same pointer.
1872 (MVT::getSizeInBits(N0.getValueType()) - MVT::getSizeInBits(VT)) / 8;
1873 SDOperand NewPtr = TLI.isLittleEndian() ? N0.getOperand(1) :
1874 DAG.getNode(ISD::ADD, PtrType, N0.getOperand(1),
1875 DAG.getConstant(PtrOff, PtrType));
1876 AddToWorkList(NewPtr.Val);
1877 SDOperand Load = DAG.getLoad(VT, N0.getOperand(0), NewPtr,N0.getOperand(2));
1879 CombineTo(N0.Val, Load, Load.getValue(1));
1880 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
1885 SDOperand DAGCombiner::visitBIT_CONVERT(SDNode *N) {
1886 SDOperand N0 = N->getOperand(0);
1887 MVT::ValueType VT = N->getValueType(0);
1889 // If the input is a constant, let getNode() fold it.
1890 if (isa<ConstantSDNode>(N0) || isa<ConstantFPSDNode>(N0)) {
1891 SDOperand Res = DAG.getNode(ISD::BIT_CONVERT, VT, N0);
1892 if (Res.Val != N) return Res;
1895 if (N0.getOpcode() == ISD::BIT_CONVERT) // conv(conv(x,t1),t2) -> conv(x,t2)
1896 return DAG.getNode(ISD::BIT_CONVERT, VT, N0.getOperand(0));
1898 // fold (conv (load x)) -> (load (conv*)x)
1899 // FIXME: These xforms need to know that the resultant load doesn't need a
1900 // higher alignment than the original!
1901 if (0 && N0.getOpcode() == ISD::LOAD && N0.hasOneUse()) {
1902 SDOperand Load = DAG.getLoad(VT, N0.getOperand(0), N0.getOperand(1),
1905 CombineTo(N0.Val, DAG.getNode(ISD::BIT_CONVERT, N0.getValueType(), Load),
1913 SDOperand DAGCombiner::visitVBIT_CONVERT(SDNode *N) {
1914 SDOperand N0 = N->getOperand(0);
1915 MVT::ValueType VT = N->getValueType(0);
1917 // If the input is a VBUILD_VECTOR with all constant elements, fold this now.
1918 // First check to see if this is all constant.
1919 if (N0.getOpcode() == ISD::VBUILD_VECTOR && N0.Val->hasOneUse() &&
1920 VT == MVT::Vector) {
1921 bool isSimple = true;
1922 for (unsigned i = 0, e = N0.getNumOperands()-2; i != e; ++i)
1923 if (N0.getOperand(i).getOpcode() != ISD::UNDEF &&
1924 N0.getOperand(i).getOpcode() != ISD::Constant &&
1925 N0.getOperand(i).getOpcode() != ISD::ConstantFP) {
1930 MVT::ValueType DestEltVT = cast<VTSDNode>(N->getOperand(2))->getVT();
1931 if (isSimple && !MVT::isVector(DestEltVT)) {
1932 return ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(N0.Val, DestEltVT);
1939 /// ConstantFoldVBIT_CONVERTofVBUILD_VECTOR - We know that BV is a vbuild_vector
1940 /// node with Constant, ConstantFP or Undef operands. DstEltVT indicates the
1941 /// destination element value type.
1942 SDOperand DAGCombiner::
1943 ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(SDNode *BV, MVT::ValueType DstEltVT) {
1944 MVT::ValueType SrcEltVT = BV->getOperand(0).getValueType();
1946 // If this is already the right type, we're done.
1947 if (SrcEltVT == DstEltVT) return SDOperand(BV, 0);
1949 unsigned SrcBitSize = MVT::getSizeInBits(SrcEltVT);
1950 unsigned DstBitSize = MVT::getSizeInBits(DstEltVT);
1952 // If this is a conversion of N elements of one type to N elements of another
1953 // type, convert each element. This handles FP<->INT cases.
1954 if (SrcBitSize == DstBitSize) {
1955 std::vector<SDOperand> Ops;
1956 for (unsigned i = 0, e = BV->getNumOperands()-2; i != e; ++i) {
1957 Ops.push_back(DAG.getNode(ISD::BIT_CONVERT, DstEltVT, BV->getOperand(i)));
1958 AddToWorkList(Ops.back().Val);
1960 Ops.push_back(*(BV->op_end()-2)); // Add num elements.
1961 Ops.push_back(DAG.getValueType(DstEltVT));
1962 return DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, Ops);
1965 // Otherwise, we're growing or shrinking the elements. To avoid having to
1966 // handle annoying details of growing/shrinking FP values, we convert them to
1968 if (MVT::isFloatingPoint(SrcEltVT)) {
1969 // Convert the input float vector to a int vector where the elements are the
1971 assert((SrcEltVT == MVT::f32 || SrcEltVT == MVT::f64) && "Unknown FP VT!");
1972 MVT::ValueType IntVT = SrcEltVT == MVT::f32 ? MVT::i32 : MVT::i64;
1973 BV = ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(BV, IntVT).Val;
1977 // Now we know the input is an integer vector. If the output is a FP type,
1978 // convert to integer first, then to FP of the right size.
1979 if (MVT::isFloatingPoint(DstEltVT)) {
1980 assert((DstEltVT == MVT::f32 || DstEltVT == MVT::f64) && "Unknown FP VT!");
1981 MVT::ValueType TmpVT = DstEltVT == MVT::f32 ? MVT::i32 : MVT::i64;
1982 SDNode *Tmp = ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(BV, TmpVT).Val;
1984 // Next, convert to FP elements of the same size.
1985 return ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(Tmp, DstEltVT);
1988 // Okay, we know the src/dst types are both integers of differing types.
1989 // Handling growing first.
1990 assert(MVT::isInteger(SrcEltVT) && MVT::isInteger(DstEltVT));
1991 if (SrcBitSize < DstBitSize) {
1992 unsigned NumInputsPerOutput = DstBitSize/SrcBitSize;
1994 std::vector<SDOperand> Ops;
1995 for (unsigned i = 0, e = BV->getNumOperands()-2; i != e;
1996 i += NumInputsPerOutput) {
1997 bool isLE = TLI.isLittleEndian();
1998 uint64_t NewBits = 0;
1999 bool EltIsUndef = true;
2000 for (unsigned j = 0; j != NumInputsPerOutput; ++j) {
2001 // Shift the previously computed bits over.
2002 NewBits <<= SrcBitSize;
2003 SDOperand Op = BV->getOperand(i+ (isLE ? (NumInputsPerOutput-j-1) : j));
2004 if (Op.getOpcode() == ISD::UNDEF) continue;
2007 NewBits |= cast<ConstantSDNode>(Op)->getValue();
2011 Ops.push_back(DAG.getNode(ISD::UNDEF, DstEltVT));
2013 Ops.push_back(DAG.getConstant(NewBits, DstEltVT));
2016 Ops.push_back(DAG.getConstant(Ops.size(), MVT::i32)); // Add num elements.
2017 Ops.push_back(DAG.getValueType(DstEltVT)); // Add element size.
2018 return DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, Ops);
2021 // Finally, this must be the case where we are shrinking elements: each input
2022 // turns into multiple outputs.
2023 unsigned NumOutputsPerInput = SrcBitSize/DstBitSize;
2024 std::vector<SDOperand> Ops;
2025 for (unsigned i = 0, e = BV->getNumOperands()-2; i != e; ++i) {
2026 if (BV->getOperand(i).getOpcode() == ISD::UNDEF) {
2027 for (unsigned j = 0; j != NumOutputsPerInput; ++j)
2028 Ops.push_back(DAG.getNode(ISD::UNDEF, DstEltVT));
2031 uint64_t OpVal = cast<ConstantSDNode>(BV->getOperand(i))->getValue();
2033 for (unsigned j = 0; j != NumOutputsPerInput; ++j) {
2034 unsigned ThisVal = OpVal & ((1ULL << DstBitSize)-1);
2035 OpVal >>= DstBitSize;
2036 Ops.push_back(DAG.getConstant(ThisVal, DstEltVT));
2039 // For big endian targets, swap the order of the pieces of each element.
2040 if (!TLI.isLittleEndian())
2041 std::reverse(Ops.end()-NumOutputsPerInput, Ops.end());
2043 Ops.push_back(DAG.getConstant(Ops.size(), MVT::i32)); // Add num elements.
2044 Ops.push_back(DAG.getValueType(DstEltVT)); // Add element size.
2045 return DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, Ops);
2050 SDOperand DAGCombiner::visitFADD(SDNode *N) {
2051 SDOperand N0 = N->getOperand(0);
2052 SDOperand N1 = N->getOperand(1);
2053 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2054 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
2055 MVT::ValueType VT = N->getValueType(0);
2057 // fold (fadd c1, c2) -> c1+c2
2059 return DAG.getNode(ISD::FADD, VT, N0, N1);
2060 // canonicalize constant to RHS
2061 if (N0CFP && !N1CFP)
2062 return DAG.getNode(ISD::FADD, VT, N1, N0);
2063 // fold (A + (-B)) -> A-B
2064 if (N1.getOpcode() == ISD::FNEG)
2065 return DAG.getNode(ISD::FSUB, VT, N0, N1.getOperand(0));
2066 // fold ((-A) + B) -> B-A
2067 if (N0.getOpcode() == ISD::FNEG)
2068 return DAG.getNode(ISD::FSUB, VT, N1, N0.getOperand(0));
2072 SDOperand DAGCombiner::visitFSUB(SDNode *N) {
2073 SDOperand N0 = N->getOperand(0);
2074 SDOperand N1 = N->getOperand(1);
2075 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2076 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
2077 MVT::ValueType VT = N->getValueType(0);
2079 // fold (fsub c1, c2) -> c1-c2
2081 return DAG.getNode(ISD::FSUB, VT, N0, N1);
2082 // fold (A-(-B)) -> A+B
2083 if (N1.getOpcode() == ISD::FNEG)
2084 return DAG.getNode(ISD::FADD, VT, N0, N1.getOperand(0));
2088 SDOperand DAGCombiner::visitFMUL(SDNode *N) {
2089 SDOperand N0 = N->getOperand(0);
2090 SDOperand N1 = N->getOperand(1);
2091 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2092 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
2093 MVT::ValueType VT = N->getValueType(0);
2095 // fold (fmul c1, c2) -> c1*c2
2097 return DAG.getNode(ISD::FMUL, VT, N0, N1);
2098 // canonicalize constant to RHS
2099 if (N0CFP && !N1CFP)
2100 return DAG.getNode(ISD::FMUL, VT, N1, N0);
2101 // fold (fmul X, 2.0) -> (fadd X, X)
2102 if (N1CFP && N1CFP->isExactlyValue(+2.0))
2103 return DAG.getNode(ISD::FADD, VT, N0, N0);
2107 SDOperand DAGCombiner::visitFDIV(SDNode *N) {
2108 SDOperand N0 = N->getOperand(0);
2109 SDOperand N1 = N->getOperand(1);
2110 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2111 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
2112 MVT::ValueType VT = N->getValueType(0);
2114 // fold (fdiv c1, c2) -> c1/c2
2116 return DAG.getNode(ISD::FDIV, VT, N0, N1);
2120 SDOperand DAGCombiner::visitFREM(SDNode *N) {
2121 SDOperand N0 = N->getOperand(0);
2122 SDOperand N1 = N->getOperand(1);
2123 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2124 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
2125 MVT::ValueType VT = N->getValueType(0);
2127 // fold (frem c1, c2) -> fmod(c1,c2)
2129 return DAG.getNode(ISD::FREM, VT, N0, N1);
2133 SDOperand DAGCombiner::visitFCOPYSIGN(SDNode *N) {
2134 SDOperand N0 = N->getOperand(0);
2135 SDOperand N1 = N->getOperand(1);
2136 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2137 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
2138 MVT::ValueType VT = N->getValueType(0);
2140 if (N0CFP && N1CFP) // Constant fold
2141 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1);
2144 // copysign(x, c1) -> fabs(x) iff ispos(c1)
2145 // copysign(x, c1) -> fneg(fabs(x)) iff isneg(c1)
2150 u.d = N1CFP->getValue();
2152 return DAG.getNode(ISD::FABS, VT, N0);
2154 return DAG.getNode(ISD::FNEG, VT, DAG.getNode(ISD::FABS, VT, N0));
2157 // copysign(fabs(x), y) -> copysign(x, y)
2158 // copysign(fneg(x), y) -> copysign(x, y)
2159 // copysign(copysign(x,z), y) -> copysign(x, y)
2160 if (N0.getOpcode() == ISD::FABS || N0.getOpcode() == ISD::FNEG ||
2161 N0.getOpcode() == ISD::FCOPYSIGN)
2162 return DAG.getNode(ISD::FCOPYSIGN, VT, N0.getOperand(0), N1);
2164 // copysign(x, abs(y)) -> abs(x)
2165 if (N1.getOpcode() == ISD::FABS)
2166 return DAG.getNode(ISD::FABS, VT, N0);
2168 // copysign(x, copysign(y,z)) -> copysign(x, z)
2169 if (N1.getOpcode() == ISD::FCOPYSIGN)
2170 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1.getOperand(1));
2172 // copysign(x, fp_extend(y)) -> copysign(x, y)
2173 // copysign(x, fp_round(y)) -> copysign(x, y)
2174 if (N1.getOpcode() == ISD::FP_EXTEND || N1.getOpcode() == ISD::FP_ROUND)
2175 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1.getOperand(0));
2182 SDOperand DAGCombiner::visitSINT_TO_FP(SDNode *N) {
2183 SDOperand N0 = N->getOperand(0);
2184 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
2185 MVT::ValueType VT = N->getValueType(0);
2187 // fold (sint_to_fp c1) -> c1fp
2189 return DAG.getNode(ISD::SINT_TO_FP, VT, N0);
2193 SDOperand DAGCombiner::visitUINT_TO_FP(SDNode *N) {
2194 SDOperand N0 = N->getOperand(0);
2195 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
2196 MVT::ValueType VT = N->getValueType(0);
2198 // fold (uint_to_fp c1) -> c1fp
2200 return DAG.getNode(ISD::UINT_TO_FP, VT, N0);
2204 SDOperand DAGCombiner::visitFP_TO_SINT(SDNode *N) {
2205 SDOperand N0 = N->getOperand(0);
2206 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2207 MVT::ValueType VT = N->getValueType(0);
2209 // fold (fp_to_sint c1fp) -> c1
2211 return DAG.getNode(ISD::FP_TO_SINT, VT, N0);
2215 SDOperand DAGCombiner::visitFP_TO_UINT(SDNode *N) {
2216 SDOperand N0 = N->getOperand(0);
2217 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2218 MVT::ValueType VT = N->getValueType(0);
2220 // fold (fp_to_uint c1fp) -> c1
2222 return DAG.getNode(ISD::FP_TO_UINT, VT, N0);
2226 SDOperand DAGCombiner::visitFP_ROUND(SDNode *N) {
2227 SDOperand N0 = N->getOperand(0);
2228 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2229 MVT::ValueType VT = N->getValueType(0);
2231 // fold (fp_round c1fp) -> c1fp
2233 return DAG.getNode(ISD::FP_ROUND, VT, N0);
2235 // fold (fp_round (fp_extend x)) -> x
2236 if (N0.getOpcode() == ISD::FP_EXTEND && VT == N0.getOperand(0).getValueType())
2237 return N0.getOperand(0);
2239 // fold (fp_round (copysign X, Y)) -> (copysign (fp_round X), Y)
2240 if (N0.getOpcode() == ISD::FCOPYSIGN && N0.Val->hasOneUse()) {
2241 SDOperand Tmp = DAG.getNode(ISD::FP_ROUND, VT, N0.getOperand(0));
2242 AddToWorkList(Tmp.Val);
2243 return DAG.getNode(ISD::FCOPYSIGN, VT, Tmp, N0.getOperand(1));
2249 SDOperand DAGCombiner::visitFP_ROUND_INREG(SDNode *N) {
2250 SDOperand N0 = N->getOperand(0);
2251 MVT::ValueType VT = N->getValueType(0);
2252 MVT::ValueType EVT = cast<VTSDNode>(N->getOperand(1))->getVT();
2253 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2255 // fold (fp_round_inreg c1fp) -> c1fp
2257 SDOperand Round = DAG.getConstantFP(N0CFP->getValue(), EVT);
2258 return DAG.getNode(ISD::FP_EXTEND, VT, Round);
2263 SDOperand DAGCombiner::visitFP_EXTEND(SDNode *N) {
2264 SDOperand N0 = N->getOperand(0);
2265 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2266 MVT::ValueType VT = N->getValueType(0);
2268 // fold (fp_extend c1fp) -> c1fp
2270 return DAG.getNode(ISD::FP_EXTEND, VT, N0);
2272 // fold (fpext (load x)) -> (fpext (fpround (extload x)))
2273 if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse() &&
2274 (!AfterLegalize||TLI.isOperationLegal(ISD::EXTLOAD, N0.getValueType()))) {
2275 SDOperand ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, VT, N0.getOperand(0),
2276 N0.getOperand(1), N0.getOperand(2),
2278 CombineTo(N, ExtLoad);
2279 CombineTo(N0.Val, DAG.getNode(ISD::FP_ROUND, N0.getValueType(), ExtLoad),
2280 ExtLoad.getValue(1));
2281 return SDOperand(N, 0); // Return N so it doesn't get rechecked!
2288 SDOperand DAGCombiner::visitFNEG(SDNode *N) {
2289 SDOperand N0 = N->getOperand(0);
2290 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2291 MVT::ValueType VT = N->getValueType(0);
2293 // fold (fneg c1) -> -c1
2295 return DAG.getNode(ISD::FNEG, VT, N0);
2296 // fold (fneg (sub x, y)) -> (sub y, x)
2297 if (N0.getOpcode() == ISD::SUB)
2298 return DAG.getNode(ISD::SUB, VT, N0.getOperand(1), N0.getOperand(0));
2299 // fold (fneg (fneg x)) -> x
2300 if (N0.getOpcode() == ISD::FNEG)
2301 return N0.getOperand(0);
2305 SDOperand DAGCombiner::visitFABS(SDNode *N) {
2306 SDOperand N0 = N->getOperand(0);
2307 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
2308 MVT::ValueType VT = N->getValueType(0);
2310 // fold (fabs c1) -> fabs(c1)
2312 return DAG.getNode(ISD::FABS, VT, N0);
2313 // fold (fabs (fabs x)) -> (fabs x)
2314 if (N0.getOpcode() == ISD::FABS)
2315 return N->getOperand(0);
2316 // fold (fabs (fneg x)) -> (fabs x)
2317 // fold (fabs (fcopysign x, y)) -> (fabs x)
2318 if (N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FCOPYSIGN)
2319 return DAG.getNode(ISD::FABS, VT, N0.getOperand(0));
2324 SDOperand DAGCombiner::visitBRCOND(SDNode *N) {
2325 SDOperand Chain = N->getOperand(0);
2326 SDOperand N1 = N->getOperand(1);
2327 SDOperand N2 = N->getOperand(2);
2328 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
2330 // never taken branch, fold to chain
2331 if (N1C && N1C->isNullValue())
2333 // unconditional branch
2334 if (N1C && N1C->getValue() == 1)
2335 return DAG.getNode(ISD::BR, MVT::Other, Chain, N2);
2336 // fold a brcond with a setcc condition into a BR_CC node if BR_CC is legal
2338 if (N1.getOpcode() == ISD::SETCC &&
2339 TLI.isOperationLegal(ISD::BR_CC, MVT::Other)) {
2340 return DAG.getNode(ISD::BR_CC, MVT::Other, Chain, N1.getOperand(2),
2341 N1.getOperand(0), N1.getOperand(1), N2);
2346 // Operand List for BR_CC: Chain, CondCC, CondLHS, CondRHS, DestBB.
2348 SDOperand DAGCombiner::visitBR_CC(SDNode *N) {
2349 CondCodeSDNode *CC = cast<CondCodeSDNode>(N->getOperand(1));
2350 SDOperand CondLHS = N->getOperand(2), CondRHS = N->getOperand(3);
2352 // Use SimplifySetCC to simplify SETCC's.
2353 SDOperand Simp = SimplifySetCC(MVT::i1, CondLHS, CondRHS, CC->get(), false);
2354 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(Simp.Val);
2356 // fold br_cc true, dest -> br dest (unconditional branch)
2357 if (SCCC && SCCC->getValue())
2358 return DAG.getNode(ISD::BR, MVT::Other, N->getOperand(0),
2360 // fold br_cc false, dest -> unconditional fall through
2361 if (SCCC && SCCC->isNullValue())
2362 return N->getOperand(0);
2363 // fold to a simpler setcc
2364 if (Simp.Val && Simp.getOpcode() == ISD::SETCC)
2365 return DAG.getNode(ISD::BR_CC, MVT::Other, N->getOperand(0),
2366 Simp.getOperand(2), Simp.getOperand(0),
2367 Simp.getOperand(1), N->getOperand(4));
2371 SDOperand DAGCombiner::visitLOAD(SDNode *N) {
2372 SDOperand Chain = N->getOperand(0);
2373 SDOperand Ptr = N->getOperand(1);
2374 SDOperand SrcValue = N->getOperand(2);
2376 // If there are no uses of the loaded value, change uses of the chain value
2377 // into uses of the chain input (i.e. delete the dead load).
2378 if (N->hasNUsesOfValue(0, 0))
2379 return CombineTo(N, DAG.getNode(ISD::UNDEF, N->getValueType(0)), Chain);
2381 // If this load is directly stored, replace the load value with the stored
2383 // TODO: Handle store large -> read small portion.
2384 // TODO: Handle TRUNCSTORE/EXTLOAD
2385 if (Chain.getOpcode() == ISD::STORE && Chain.getOperand(2) == Ptr &&
2386 Chain.getOperand(1).getValueType() == N->getValueType(0))
2387 return CombineTo(N, Chain.getOperand(1), Chain);
2392 /// visitXEXTLOAD - Handle EXTLOAD/ZEXTLOAD/SEXTLOAD.
2393 SDOperand DAGCombiner::visitXEXTLOAD(SDNode *N) {
2394 SDOperand Chain = N->getOperand(0);
2395 SDOperand Ptr = N->getOperand(1);
2396 SDOperand SrcValue = N->getOperand(2);
2397 SDOperand EVT = N->getOperand(3);
2399 // If there are no uses of the loaded value, change uses of the chain value
2400 // into uses of the chain input (i.e. delete the dead load).
2401 if (N->hasNUsesOfValue(0, 0))
2402 return CombineTo(N, DAG.getNode(ISD::UNDEF, N->getValueType(0)), Chain);
2407 SDOperand DAGCombiner::visitSTORE(SDNode *N) {
2408 SDOperand Chain = N->getOperand(0);
2409 SDOperand Value = N->getOperand(1);
2410 SDOperand Ptr = N->getOperand(2);
2411 SDOperand SrcValue = N->getOperand(3);
2413 // If this is a store that kills a previous store, remove the previous store.
2414 if (Chain.getOpcode() == ISD::STORE && Chain.getOperand(2) == Ptr &&
2415 Chain.Val->hasOneUse() /* Avoid introducing DAG cycles */ &&
2416 // Make sure that these stores are the same value type:
2417 // FIXME: we really care that the second store is >= size of the first.
2418 Value.getValueType() == Chain.getOperand(1).getValueType()) {
2419 // Create a new store of Value that replaces both stores.
2420 SDNode *PrevStore = Chain.Val;
2421 if (PrevStore->getOperand(1) == Value) // Same value multiply stored.
2423 SDOperand NewStore = DAG.getNode(ISD::STORE, MVT::Other,
2424 PrevStore->getOperand(0), Value, Ptr,
2426 CombineTo(N, NewStore); // Nuke this store.
2427 CombineTo(PrevStore, NewStore); // Nuke the previous store.
2428 return SDOperand(N, 0);
2431 // If this is a store of a bit convert, store the input value.
2432 // FIXME: This needs to know that the resultant store does not need a
2433 // higher alignment than the original.
2434 if (0 && Value.getOpcode() == ISD::BIT_CONVERT)
2435 return DAG.getNode(ISD::STORE, MVT::Other, Chain, Value.getOperand(0),
2441 SDOperand DAGCombiner::visitINSERT_VECTOR_ELT(SDNode *N) {
2442 SDOperand InVec = N->getOperand(0);
2443 SDOperand InVal = N->getOperand(1);
2444 SDOperand EltNo = N->getOperand(2);
2446 // If the invec is a BUILD_VECTOR and if EltNo is a constant, build a new
2447 // vector with the inserted element.
2448 if (InVec.getOpcode() == ISD::BUILD_VECTOR && isa<ConstantSDNode>(EltNo)) {
2449 unsigned Elt = cast<ConstantSDNode>(EltNo)->getValue();
2450 std::vector<SDOperand> Ops(InVec.Val->op_begin(), InVec.Val->op_end());
2451 if (Elt < Ops.size())
2453 return DAG.getNode(ISD::BUILD_VECTOR, InVec.getValueType(), Ops);
2459 SDOperand DAGCombiner::visitVINSERT_VECTOR_ELT(SDNode *N) {
2460 SDOperand InVec = N->getOperand(0);
2461 SDOperand InVal = N->getOperand(1);
2462 SDOperand EltNo = N->getOperand(2);
2463 SDOperand NumElts = N->getOperand(3);
2464 SDOperand EltType = N->getOperand(4);
2466 // If the invec is a VBUILD_VECTOR and if EltNo is a constant, build a new
2467 // vector with the inserted element.
2468 if (InVec.getOpcode() == ISD::VBUILD_VECTOR && isa<ConstantSDNode>(EltNo)) {
2469 unsigned Elt = cast<ConstantSDNode>(EltNo)->getValue();
2470 std::vector<SDOperand> Ops(InVec.Val->op_begin(), InVec.Val->op_end());
2471 if (Elt < Ops.size()-2)
2473 return DAG.getNode(ISD::VBUILD_VECTOR, InVec.getValueType(), Ops);
2479 SDOperand DAGCombiner::visitVBUILD_VECTOR(SDNode *N) {
2480 unsigned NumInScalars = N->getNumOperands()-2;
2481 SDOperand NumElts = N->getOperand(NumInScalars);
2482 SDOperand EltType = N->getOperand(NumInScalars+1);
2484 // Check to see if this is a VBUILD_VECTOR of a bunch of VEXTRACT_VECTOR_ELT
2485 // operations. If so, and if the EXTRACT_ELT vector inputs come from at most
2486 // two distinct vectors, turn this into a shuffle node.
2487 SDOperand VecIn1, VecIn2;
2488 for (unsigned i = 0; i != NumInScalars; ++i) {
2489 // Ignore undef inputs.
2490 if (N->getOperand(i).getOpcode() == ISD::UNDEF) continue;
2492 // If this input is something other than a VEXTRACT_VECTOR_ELT with a
2493 // constant index, bail out.
2494 if (N->getOperand(i).getOpcode() != ISD::VEXTRACT_VECTOR_ELT ||
2495 !isa<ConstantSDNode>(N->getOperand(i).getOperand(1))) {
2496 VecIn1 = VecIn2 = SDOperand(0, 0);
2500 // If the input vector type disagrees with the result of the vbuild_vector,
2501 // we can't make a shuffle.
2502 SDOperand ExtractedFromVec = N->getOperand(i).getOperand(0);
2503 if (*(ExtractedFromVec.Val->op_end()-2) != NumElts ||
2504 *(ExtractedFromVec.Val->op_end()-1) != EltType) {
2505 VecIn1 = VecIn2 = SDOperand(0, 0);
2509 // Otherwise, remember this. We allow up to two distinct input vectors.
2510 if (ExtractedFromVec == VecIn1 || ExtractedFromVec == VecIn2)
2513 if (VecIn1.Val == 0) {
2514 VecIn1 = ExtractedFromVec;
2515 } else if (VecIn2.Val == 0) {
2516 VecIn2 = ExtractedFromVec;
2519 VecIn1 = VecIn2 = SDOperand(0, 0);
2524 // If everything is good, we can make a shuffle operation.
2526 std::vector<SDOperand> BuildVecIndices;
2527 for (unsigned i = 0; i != NumInScalars; ++i) {
2528 if (N->getOperand(i).getOpcode() == ISD::UNDEF) {
2529 BuildVecIndices.push_back(DAG.getNode(ISD::UNDEF, MVT::i32));
2533 SDOperand Extract = N->getOperand(i);
2535 // If extracting from the first vector, just use the index directly.
2536 if (Extract.getOperand(0) == VecIn1) {
2537 BuildVecIndices.push_back(Extract.getOperand(1));
2541 // Otherwise, use InIdx + VecSize
2542 unsigned Idx = cast<ConstantSDNode>(Extract.getOperand(1))->getValue();
2543 BuildVecIndices.push_back(DAG.getConstant(Idx+NumInScalars, MVT::i32));
2546 // Add count and size info.
2547 BuildVecIndices.push_back(NumElts);
2548 BuildVecIndices.push_back(DAG.getValueType(MVT::i32));
2550 // Return the new VVECTOR_SHUFFLE node.
2551 std::vector<SDOperand> Ops;
2552 Ops.push_back(VecIn1);
2554 Ops.push_back(VecIn2);
2556 // Use an undef vbuild_vector as input for the second operand.
2557 std::vector<SDOperand> UnOps(NumInScalars,
2558 DAG.getNode(ISD::UNDEF,
2559 cast<VTSDNode>(EltType)->getVT()));
2560 UnOps.push_back(NumElts);
2561 UnOps.push_back(EltType);
2562 Ops.push_back(DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, UnOps));
2563 AddToWorkList(Ops.back().Val);
2565 Ops.push_back(DAG.getNode(ISD::VBUILD_VECTOR,MVT::Vector, BuildVecIndices));
2566 Ops.push_back(NumElts);
2567 Ops.push_back(EltType);
2568 return DAG.getNode(ISD::VVECTOR_SHUFFLE, MVT::Vector, Ops);
2574 SDOperand DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) {
2575 SDOperand ShufMask = N->getOperand(2);
2576 unsigned NumElts = ShufMask.getNumOperands();
2578 // If the shuffle mask is an identity operation on the LHS, return the LHS.
2579 bool isIdentity = true;
2580 for (unsigned i = 0; i != NumElts; ++i) {
2581 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF &&
2582 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() != i) {
2587 if (isIdentity) return N->getOperand(0);
2589 // If the shuffle mask is an identity operation on the RHS, return the RHS.
2591 for (unsigned i = 0; i != NumElts; ++i) {
2592 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF &&
2593 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() != i+NumElts) {
2598 if (isIdentity) return N->getOperand(1);
2600 // If the LHS and the RHS are the same node, turn the RHS into an undef.
2601 if (N->getOperand(0) == N->getOperand(1)) {
2602 if (N->getOperand(0).getOpcode() == ISD::UNDEF)
2603 return DAG.getNode(ISD::UNDEF, N->getValueType(0));
2604 // Check the SHUFFLE mask, mapping any inputs from the 2nd operand into the
2606 std::vector<SDOperand> MappedOps;
2607 for (unsigned i = 0, e = ShufMask.getNumOperands(); i != e; ++i) {
2608 if (ShufMask.getOperand(i).getOpcode() == ISD::UNDEF ||
2609 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() < NumElts) {
2610 MappedOps.push_back(ShufMask.getOperand(i));
2613 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() - NumElts;
2614 MappedOps.push_back(DAG.getConstant(NewIdx, MVT::i32));
2617 ShufMask = DAG.getNode(ISD::BUILD_VECTOR, ShufMask.getValueType(),
2619 AddToWorkList(ShufMask.Val);
2620 return DAG.getNode(ISD::VECTOR_SHUFFLE, N->getValueType(0),
2622 DAG.getNode(ISD::UNDEF, N->getValueType(0)),
2629 SDOperand DAGCombiner::visitVVECTOR_SHUFFLE(SDNode *N) {
2630 SDOperand ShufMask = N->getOperand(2);
2631 unsigned NumElts = ShufMask.getNumOperands()-2;
2633 // If the shuffle mask is an identity operation on the LHS, return the LHS.
2634 bool isIdentity = true;
2635 for (unsigned i = 0; i != NumElts; ++i) {
2636 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF &&
2637 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() != i) {
2642 if (isIdentity) return N->getOperand(0);
2644 // If the shuffle mask is an identity operation on the RHS, return the RHS.
2646 for (unsigned i = 0; i != NumElts; ++i) {
2647 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF &&
2648 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() != i+NumElts) {
2653 if (isIdentity) return N->getOperand(1);
2655 // If the LHS and the RHS are the same node, turn the RHS into an undef.
2656 if (N->getOperand(0) == N->getOperand(1)) {
2657 // Check the SHUFFLE mask, mapping any inputs from the 2nd operand into the
2659 std::vector<SDOperand> MappedOps;
2660 for (unsigned i = 0; i != NumElts; ++i) {
2661 if (ShufMask.getOperand(i).getOpcode() == ISD::UNDEF ||
2662 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() < NumElts) {
2663 MappedOps.push_back(ShufMask.getOperand(i));
2666 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() - NumElts;
2667 MappedOps.push_back(DAG.getConstant(NewIdx, MVT::i32));
2670 // Add the type/#elts values.
2671 MappedOps.push_back(ShufMask.getOperand(NumElts));
2672 MappedOps.push_back(ShufMask.getOperand(NumElts+1));
2674 ShufMask = DAG.getNode(ISD::VBUILD_VECTOR, ShufMask.getValueType(),
2676 AddToWorkList(ShufMask.Val);
2678 // Build the undef vector.
2679 SDOperand UDVal = DAG.getNode(ISD::UNDEF, MappedOps[0].getValueType());
2680 for (unsigned i = 0; i != NumElts; ++i)
2681 MappedOps[i] = UDVal;
2682 MappedOps[NumElts ] = *(N->getOperand(0).Val->op_end()-2);
2683 MappedOps[NumElts+1] = *(N->getOperand(0).Val->op_end()-1);
2684 UDVal = DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, MappedOps);
2686 return DAG.getNode(ISD::VVECTOR_SHUFFLE, MVT::Vector,
2687 N->getOperand(0), UDVal, ShufMask,
2688 MappedOps[NumElts], MappedOps[NumElts+1]);
2694 /// XformToShuffleWithZero - Returns a vector_shuffle if it able to transform
2695 /// a VAND to a vector_shuffle with the destination vector and a zero vector.
2696 /// e.g. VAND V, <0xffffffff, 0, 0xffffffff, 0>. ==>
2697 /// vector_shuffle V, Zero, <0, 4, 2, 4>
2698 SDOperand DAGCombiner::XformToShuffleWithZero(SDNode *N) {
2699 SDOperand LHS = N->getOperand(0);
2700 SDOperand RHS = N->getOperand(1);
2701 if (N->getOpcode() == ISD::VAND) {
2702 SDOperand DstVecSize = *(LHS.Val->op_end()-2);
2703 SDOperand DstVecEVT = *(LHS.Val->op_end()-1);
2704 if (RHS.getOpcode() == ISD::VBIT_CONVERT)
2705 RHS = RHS.getOperand(0);
2706 if (RHS.getOpcode() == ISD::VBUILD_VECTOR) {
2707 std::vector<SDOperand> IdxOps;
2708 unsigned NumOps = RHS.getNumOperands();
2709 unsigned NumElts = NumOps-2;
2710 MVT::ValueType EVT = cast<VTSDNode>(RHS.getOperand(NumOps-1))->getVT();
2711 for (unsigned i = 0; i != NumElts; ++i) {
2712 SDOperand Elt = RHS.getOperand(i);
2713 if (!isa<ConstantSDNode>(Elt))
2715 else if (cast<ConstantSDNode>(Elt)->isAllOnesValue())
2716 IdxOps.push_back(DAG.getConstant(i, EVT));
2717 else if (cast<ConstantSDNode>(Elt)->isNullValue())
2718 IdxOps.push_back(DAG.getConstant(NumElts, EVT));
2723 // Let's see if the target supports this vector_shuffle.
2724 if (!TLI.isVectorClearMaskLegal(IdxOps, EVT, DAG))
2727 // Return the new VVECTOR_SHUFFLE node.
2728 SDOperand NumEltsNode = DAG.getConstant(NumElts, MVT::i32);
2729 SDOperand EVTNode = DAG.getValueType(EVT);
2730 std::vector<SDOperand> Ops;
2731 LHS = DAG.getNode(ISD::VBIT_CONVERT, MVT::Vector, LHS, NumEltsNode, EVTNode);
2733 AddToWorkList(LHS.Val);
2734 std::vector<SDOperand> ZeroOps(NumElts, DAG.getConstant(0, EVT));
2735 ZeroOps.push_back(NumEltsNode);
2736 ZeroOps.push_back(EVTNode);
2737 Ops.push_back(DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, ZeroOps));
2738 IdxOps.push_back(NumEltsNode);
2739 IdxOps.push_back(EVTNode);
2740 Ops.push_back(DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, IdxOps));
2741 Ops.push_back(NumEltsNode);
2742 Ops.push_back(EVTNode);
2743 SDOperand Result = DAG.getNode(ISD::VVECTOR_SHUFFLE, MVT::Vector, Ops);
2744 if (NumEltsNode != DstVecSize || EVTNode != DstVecEVT) {
2745 Result = DAG.getNode(ISD::VBIT_CONVERT, MVT::Vector, Result,
2746 DstVecSize, DstVecEVT);
2754 /// visitVBinOp - Visit a binary vector operation, like VADD. IntOp indicates
2755 /// the scalar operation of the vop if it is operating on an integer vector
2756 /// (e.g. ADD) and FPOp indicates the FP version (e.g. FADD).
2757 SDOperand DAGCombiner::visitVBinOp(SDNode *N, ISD::NodeType IntOp,
2758 ISD::NodeType FPOp) {
2759 MVT::ValueType EltType = cast<VTSDNode>(*(N->op_end()-1))->getVT();
2760 ISD::NodeType ScalarOp = MVT::isInteger(EltType) ? IntOp : FPOp;
2761 SDOperand LHS = N->getOperand(0);
2762 SDOperand RHS = N->getOperand(1);
2763 SDOperand Shuffle = XformToShuffleWithZero(N);
2764 if (Shuffle.Val) return Shuffle;
2766 // If the LHS and RHS are VBUILD_VECTOR nodes, see if we can constant fold
2768 if (LHS.getOpcode() == ISD::VBUILD_VECTOR &&
2769 RHS.getOpcode() == ISD::VBUILD_VECTOR) {
2770 std::vector<SDOperand> Ops;
2771 for (unsigned i = 0, e = LHS.getNumOperands()-2; i != e; ++i) {
2772 SDOperand LHSOp = LHS.getOperand(i);
2773 SDOperand RHSOp = RHS.getOperand(i);
2774 // If these two elements can't be folded, bail out.
2775 if ((LHSOp.getOpcode() != ISD::UNDEF &&
2776 LHSOp.getOpcode() != ISD::Constant &&
2777 LHSOp.getOpcode() != ISD::ConstantFP) ||
2778 (RHSOp.getOpcode() != ISD::UNDEF &&
2779 RHSOp.getOpcode() != ISD::Constant &&
2780 RHSOp.getOpcode() != ISD::ConstantFP))
2782 // Can't fold divide by zero.
2783 if (N->getOpcode() == ISD::VSDIV || N->getOpcode() == ISD::VUDIV) {
2784 if ((RHSOp.getOpcode() == ISD::Constant &&
2785 cast<ConstantSDNode>(RHSOp.Val)->isNullValue()) ||
2786 (RHSOp.getOpcode() == ISD::ConstantFP &&
2787 !cast<ConstantFPSDNode>(RHSOp.Val)->getValue()))
2790 Ops.push_back(DAG.getNode(ScalarOp, EltType, LHSOp, RHSOp));
2791 AddToWorkList(Ops.back().Val);
2792 assert((Ops.back().getOpcode() == ISD::UNDEF ||
2793 Ops.back().getOpcode() == ISD::Constant ||
2794 Ops.back().getOpcode() == ISD::ConstantFP) &&
2795 "Scalar binop didn't fold!");
2798 if (Ops.size() == LHS.getNumOperands()-2) {
2799 Ops.push_back(*(LHS.Val->op_end()-2));
2800 Ops.push_back(*(LHS.Val->op_end()-1));
2801 return DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, Ops);
2808 SDOperand DAGCombiner::SimplifySelect(SDOperand N0, SDOperand N1, SDOperand N2){
2809 assert(N0.getOpcode() ==ISD::SETCC && "First argument must be a SetCC node!");
2811 SDOperand SCC = SimplifySelectCC(N0.getOperand(0), N0.getOperand(1), N1, N2,
2812 cast<CondCodeSDNode>(N0.getOperand(2))->get());
2813 // If we got a simplified select_cc node back from SimplifySelectCC, then
2814 // break it down into a new SETCC node, and a new SELECT node, and then return
2815 // the SELECT node, since we were called with a SELECT node.
2817 // Check to see if we got a select_cc back (to turn into setcc/select).
2818 // Otherwise, just return whatever node we got back, like fabs.
2819 if (SCC.getOpcode() == ISD::SELECT_CC) {
2820 SDOperand SETCC = DAG.getNode(ISD::SETCC, N0.getValueType(),
2821 SCC.getOperand(0), SCC.getOperand(1),
2823 AddToWorkList(SETCC.Val);
2824 return DAG.getNode(ISD::SELECT, SCC.getValueType(), SCC.getOperand(2),
2825 SCC.getOperand(3), SETCC);
2832 /// SimplifySelectOps - Given a SELECT or a SELECT_CC node, where LHS and RHS
2833 /// are the two values being selected between, see if we can simplify the
2834 /// select. Callers of this should assume that TheSelect is deleted if this
2835 /// returns true. As such, they should return the appropriate thing (e.g. the
2836 /// node) back to the top-level of the DAG combiner loop to avoid it being
2839 bool DAGCombiner::SimplifySelectOps(SDNode *TheSelect, SDOperand LHS,
2842 // If this is a select from two identical things, try to pull the operation
2843 // through the select.
2844 if (LHS.getOpcode() == RHS.getOpcode() && LHS.hasOneUse() && RHS.hasOneUse()){
2846 std::cerr << "SELECT: ["; LHS.Val->dump();
2847 std::cerr << "] ["; RHS.Val->dump();
2851 // If this is a load and the token chain is identical, replace the select
2852 // of two loads with a load through a select of the address to load from.
2853 // This triggers in things like "select bool X, 10.0, 123.0" after the FP
2854 // constants have been dropped into the constant pool.
2855 if ((LHS.getOpcode() == ISD::LOAD ||
2856 LHS.getOpcode() == ISD::EXTLOAD ||
2857 LHS.getOpcode() == ISD::ZEXTLOAD ||
2858 LHS.getOpcode() == ISD::SEXTLOAD) &&
2859 // Token chains must be identical.
2860 LHS.getOperand(0) == RHS.getOperand(0) &&
2861 // If this is an EXTLOAD, the VT's must match.
2862 (LHS.getOpcode() == ISD::LOAD ||
2863 LHS.getOperand(3) == RHS.getOperand(3))) {
2864 // FIXME: this conflates two src values, discarding one. This is not
2865 // the right thing to do, but nothing uses srcvalues now. When they do,
2866 // turn SrcValue into a list of locations.
2868 if (TheSelect->getOpcode() == ISD::SELECT)
2869 Addr = DAG.getNode(ISD::SELECT, LHS.getOperand(1).getValueType(),
2870 TheSelect->getOperand(0), LHS.getOperand(1),
2873 Addr = DAG.getNode(ISD::SELECT_CC, LHS.getOperand(1).getValueType(),
2874 TheSelect->getOperand(0),
2875 TheSelect->getOperand(1),
2876 LHS.getOperand(1), RHS.getOperand(1),
2877 TheSelect->getOperand(4));
2880 if (LHS.getOpcode() == ISD::LOAD)
2881 Load = DAG.getLoad(TheSelect->getValueType(0), LHS.getOperand(0),
2882 Addr, LHS.getOperand(2));
2884 Load = DAG.getExtLoad(LHS.getOpcode(), TheSelect->getValueType(0),
2885 LHS.getOperand(0), Addr, LHS.getOperand(2),
2886 cast<VTSDNode>(LHS.getOperand(3))->getVT());
2887 // Users of the select now use the result of the load.
2888 CombineTo(TheSelect, Load);
2890 // Users of the old loads now use the new load's chain. We know the
2891 // old-load value is dead now.
2892 CombineTo(LHS.Val, Load.getValue(0), Load.getValue(1));
2893 CombineTo(RHS.Val, Load.getValue(0), Load.getValue(1));
2901 SDOperand DAGCombiner::SimplifySelectCC(SDOperand N0, SDOperand N1,
2902 SDOperand N2, SDOperand N3,
2905 MVT::ValueType VT = N2.getValueType();
2906 //ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val);
2907 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
2908 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2.Val);
2909 ConstantSDNode *N3C = dyn_cast<ConstantSDNode>(N3.Val);
2911 // Determine if the condition we're dealing with is constant
2912 SDOperand SCC = SimplifySetCC(TLI.getSetCCResultTy(), N0, N1, CC, false);
2913 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.Val);
2915 // fold select_cc true, x, y -> x
2916 if (SCCC && SCCC->getValue())
2918 // fold select_cc false, x, y -> y
2919 if (SCCC && SCCC->getValue() == 0)
2922 // Check to see if we can simplify the select into an fabs node
2923 if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N1)) {
2924 // Allow either -0.0 or 0.0
2925 if (CFP->getValue() == 0.0) {
2926 // select (setg[te] X, +/-0.0), X, fneg(X) -> fabs
2927 if ((CC == ISD::SETGE || CC == ISD::SETGT) &&
2928 N0 == N2 && N3.getOpcode() == ISD::FNEG &&
2929 N2 == N3.getOperand(0))
2930 return DAG.getNode(ISD::FABS, VT, N0);
2932 // select (setl[te] X, +/-0.0), fneg(X), X -> fabs
2933 if ((CC == ISD::SETLT || CC == ISD::SETLE) &&
2934 N0 == N3 && N2.getOpcode() == ISD::FNEG &&
2935 N2.getOperand(0) == N3)
2936 return DAG.getNode(ISD::FABS, VT, N3);
2940 // Check to see if we can perform the "gzip trick", transforming
2941 // select_cc setlt X, 0, A, 0 -> and (sra X, size(X)-1), A
2942 if (N1C && N1C->isNullValue() && N3C && N3C->isNullValue() &&
2943 MVT::isInteger(N0.getValueType()) &&
2944 MVT::isInteger(N2.getValueType()) && CC == ISD::SETLT) {
2945 MVT::ValueType XType = N0.getValueType();
2946 MVT::ValueType AType = N2.getValueType();
2947 if (XType >= AType) {
2948 // and (sra X, size(X)-1, A) -> "and (srl X, C2), A" iff A is a
2949 // single-bit constant.
2950 if (N2C && ((N2C->getValue() & (N2C->getValue()-1)) == 0)) {
2951 unsigned ShCtV = Log2_64(N2C->getValue());
2952 ShCtV = MVT::getSizeInBits(XType)-ShCtV-1;
2953 SDOperand ShCt = DAG.getConstant(ShCtV, TLI.getShiftAmountTy());
2954 SDOperand Shift = DAG.getNode(ISD::SRL, XType, N0, ShCt);
2955 AddToWorkList(Shift.Val);
2956 if (XType > AType) {
2957 Shift = DAG.getNode(ISD::TRUNCATE, AType, Shift);
2958 AddToWorkList(Shift.Val);
2960 return DAG.getNode(ISD::AND, AType, Shift, N2);
2962 SDOperand Shift = DAG.getNode(ISD::SRA, XType, N0,
2963 DAG.getConstant(MVT::getSizeInBits(XType)-1,
2964 TLI.getShiftAmountTy()));
2965 AddToWorkList(Shift.Val);
2966 if (XType > AType) {
2967 Shift = DAG.getNode(ISD::TRUNCATE, AType, Shift);
2968 AddToWorkList(Shift.Val);
2970 return DAG.getNode(ISD::AND, AType, Shift, N2);
2974 // fold select C, 16, 0 -> shl C, 4
2975 if (N2C && N3C && N3C->isNullValue() && isPowerOf2_64(N2C->getValue()) &&
2976 TLI.getSetCCResultContents() == TargetLowering::ZeroOrOneSetCCResult) {
2977 // Get a SetCC of the condition
2978 // FIXME: Should probably make sure that setcc is legal if we ever have a
2979 // target where it isn't.
2980 SDOperand Temp, SCC;
2981 // cast from setcc result type to select result type
2982 if (AfterLegalize) {
2983 SCC = DAG.getSetCC(TLI.getSetCCResultTy(), N0, N1, CC);
2984 Temp = DAG.getZeroExtendInReg(SCC, N2.getValueType());
2986 SCC = DAG.getSetCC(MVT::i1, N0, N1, CC);
2987 Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getValueType(), SCC);
2989 AddToWorkList(SCC.Val);
2990 AddToWorkList(Temp.Val);
2991 // shl setcc result by log2 n2c
2992 return DAG.getNode(ISD::SHL, N2.getValueType(), Temp,
2993 DAG.getConstant(Log2_64(N2C->getValue()),
2994 TLI.getShiftAmountTy()));
2997 // Check to see if this is the equivalent of setcc
2998 // FIXME: Turn all of these into setcc if setcc if setcc is legal
2999 // otherwise, go ahead with the folds.
3000 if (0 && N3C && N3C->isNullValue() && N2C && (N2C->getValue() == 1ULL)) {
3001 MVT::ValueType XType = N0.getValueType();
3002 if (TLI.isOperationLegal(ISD::SETCC, TLI.getSetCCResultTy())) {
3003 SDOperand Res = DAG.getSetCC(TLI.getSetCCResultTy(), N0, N1, CC);
3004 if (Res.getValueType() != VT)
3005 Res = DAG.getNode(ISD::ZERO_EXTEND, VT, Res);
3009 // seteq X, 0 -> srl (ctlz X, log2(size(X)))
3010 if (N1C && N1C->isNullValue() && CC == ISD::SETEQ &&
3011 TLI.isOperationLegal(ISD::CTLZ, XType)) {
3012 SDOperand Ctlz = DAG.getNode(ISD::CTLZ, XType, N0);
3013 return DAG.getNode(ISD::SRL, XType, Ctlz,
3014 DAG.getConstant(Log2_32(MVT::getSizeInBits(XType)),
3015 TLI.getShiftAmountTy()));
3017 // setgt X, 0 -> srl (and (-X, ~X), size(X)-1)
3018 if (N1C && N1C->isNullValue() && CC == ISD::SETGT) {
3019 SDOperand NegN0 = DAG.getNode(ISD::SUB, XType, DAG.getConstant(0, XType),
3021 SDOperand NotN0 = DAG.getNode(ISD::XOR, XType, N0,
3022 DAG.getConstant(~0ULL, XType));
3023 return DAG.getNode(ISD::SRL, XType,
3024 DAG.getNode(ISD::AND, XType, NegN0, NotN0),
3025 DAG.getConstant(MVT::getSizeInBits(XType)-1,
3026 TLI.getShiftAmountTy()));
3028 // setgt X, -1 -> xor (srl (X, size(X)-1), 1)
3029 if (N1C && N1C->isAllOnesValue() && CC == ISD::SETGT) {
3030 SDOperand Sign = DAG.getNode(ISD::SRL, XType, N0,
3031 DAG.getConstant(MVT::getSizeInBits(XType)-1,
3032 TLI.getShiftAmountTy()));
3033 return DAG.getNode(ISD::XOR, XType, Sign, DAG.getConstant(1, XType));
3037 // Check to see if this is an integer abs. select_cc setl[te] X, 0, -X, X ->
3038 // Y = sra (X, size(X)-1); xor (add (X, Y), Y)
3039 if (N1C && N1C->isNullValue() && (CC == ISD::SETLT || CC == ISD::SETLE) &&
3040 N0 == N3 && N2.getOpcode() == ISD::SUB && N0 == N2.getOperand(1)) {
3041 if (ConstantSDNode *SubC = dyn_cast<ConstantSDNode>(N2.getOperand(0))) {
3042 MVT::ValueType XType = N0.getValueType();
3043 if (SubC->isNullValue() && MVT::isInteger(XType)) {
3044 SDOperand Shift = DAG.getNode(ISD::SRA, XType, N0,
3045 DAG.getConstant(MVT::getSizeInBits(XType)-1,
3046 TLI.getShiftAmountTy()));
3047 SDOperand Add = DAG.getNode(ISD::ADD, XType, N0, Shift);
3048 AddToWorkList(Shift.Val);
3049 AddToWorkList(Add.Val);
3050 return DAG.getNode(ISD::XOR, XType, Add, Shift);
3058 SDOperand DAGCombiner::SimplifySetCC(MVT::ValueType VT, SDOperand N0,
3059 SDOperand N1, ISD::CondCode Cond,
3060 bool foldBooleans) {
3061 // These setcc operations always fold.
3065 case ISD::SETFALSE2: return DAG.getConstant(0, VT);
3067 case ISD::SETTRUE2: return DAG.getConstant(1, VT);
3070 if (ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val)) {
3071 uint64_t C1 = N1C->getValue();
3072 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val)) {
3073 uint64_t C0 = N0C->getValue();
3075 // Sign extend the operands if required
3076 if (ISD::isSignedIntSetCC(Cond)) {
3077 C0 = N0C->getSignExtended();
3078 C1 = N1C->getSignExtended();
3082 default: assert(0 && "Unknown integer setcc!");
3083 case ISD::SETEQ: return DAG.getConstant(C0 == C1, VT);
3084 case ISD::SETNE: return DAG.getConstant(C0 != C1, VT);
3085 case ISD::SETULT: return DAG.getConstant(C0 < C1, VT);
3086 case ISD::SETUGT: return DAG.getConstant(C0 > C1, VT);
3087 case ISD::SETULE: return DAG.getConstant(C0 <= C1, VT);
3088 case ISD::SETUGE: return DAG.getConstant(C0 >= C1, VT);
3089 case ISD::SETLT: return DAG.getConstant((int64_t)C0 < (int64_t)C1, VT);
3090 case ISD::SETGT: return DAG.getConstant((int64_t)C0 > (int64_t)C1, VT);
3091 case ISD::SETLE: return DAG.getConstant((int64_t)C0 <= (int64_t)C1, VT);
3092 case ISD::SETGE: return DAG.getConstant((int64_t)C0 >= (int64_t)C1, VT);
3095 // If the LHS is a ZERO_EXTEND, perform the comparison on the input.
3096 if (N0.getOpcode() == ISD::ZERO_EXTEND) {
3097 unsigned InSize = MVT::getSizeInBits(N0.getOperand(0).getValueType());
3099 // If the comparison constant has bits in the upper part, the
3100 // zero-extended value could never match.
3101 if (C1 & (~0ULL << InSize)) {
3102 unsigned VSize = MVT::getSizeInBits(N0.getValueType());
3106 case ISD::SETEQ: return DAG.getConstant(0, VT);
3109 case ISD::SETNE: return DAG.getConstant(1, VT);
3112 // True if the sign bit of C1 is set.
3113 return DAG.getConstant((C1 & (1ULL << VSize)) != 0, VT);
3116 // True if the sign bit of C1 isn't set.
3117 return DAG.getConstant((C1 & (1ULL << VSize)) == 0, VT);
3123 // Otherwise, we can perform the comparison with the low bits.
3131 return DAG.getSetCC(VT, N0.getOperand(0),
3132 DAG.getConstant(C1, N0.getOperand(0).getValueType()),
3135 break; // todo, be more careful with signed comparisons
3137 } else if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
3138 (Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
3139 MVT::ValueType ExtSrcTy = cast<VTSDNode>(N0.getOperand(1))->getVT();
3140 unsigned ExtSrcTyBits = MVT::getSizeInBits(ExtSrcTy);
3141 MVT::ValueType ExtDstTy = N0.getValueType();
3142 unsigned ExtDstTyBits = MVT::getSizeInBits(ExtDstTy);
3144 // If the extended part has any inconsistent bits, it cannot ever
3145 // compare equal. In other words, they have to be all ones or all
3148 (~0ULL >> (64-ExtSrcTyBits)) & (~0ULL << (ExtDstTyBits-1));
3149 if ((C1 & ExtBits) != 0 && (C1 & ExtBits) != ExtBits)
3150 return DAG.getConstant(Cond == ISD::SETNE, VT);
3153 MVT::ValueType Op0Ty = N0.getOperand(0).getValueType();
3154 if (Op0Ty == ExtSrcTy) {
3155 ZextOp = N0.getOperand(0);
3157 int64_t Imm = ~0ULL >> (64-ExtSrcTyBits);
3158 ZextOp = DAG.getNode(ISD::AND, Op0Ty, N0.getOperand(0),
3159 DAG.getConstant(Imm, Op0Ty));
3161 AddToWorkList(ZextOp.Val);
3162 // Otherwise, make this a use of a zext.
3163 return DAG.getSetCC(VT, ZextOp,
3164 DAG.getConstant(C1 & (~0ULL>>(64-ExtSrcTyBits)),
3167 } else if ((N1C->getValue() == 0 || N1C->getValue() == 1) &&
3168 (Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
3169 (N0.getOpcode() == ISD::XOR ||
3170 (N0.getOpcode() == ISD::AND &&
3171 N0.getOperand(0).getOpcode() == ISD::XOR &&
3172 N0.getOperand(1) == N0.getOperand(0).getOperand(1))) &&
3173 isa<ConstantSDNode>(N0.getOperand(1)) &&
3174 cast<ConstantSDNode>(N0.getOperand(1))->getValue() == 1) {
3175 // If this is (X^1) == 0/1, swap the RHS and eliminate the xor. We can
3176 // only do this if the top bits are known zero.
3177 if (TLI.MaskedValueIsZero(N1,
3178 MVT::getIntVTBitMask(N0.getValueType())-1)) {
3179 // Okay, get the un-inverted input value.
3181 if (N0.getOpcode() == ISD::XOR)
3182 Val = N0.getOperand(0);
3184 assert(N0.getOpcode() == ISD::AND &&
3185 N0.getOperand(0).getOpcode() == ISD::XOR);
3186 // ((X^1)&1)^1 -> X & 1
3187 Val = DAG.getNode(ISD::AND, N0.getValueType(),
3188 N0.getOperand(0).getOperand(0), N0.getOperand(1));
3190 return DAG.getSetCC(VT, Val, N1,
3191 Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
3195 uint64_t MinVal, MaxVal;
3196 unsigned OperandBitSize = MVT::getSizeInBits(N1C->getValueType(0));
3197 if (ISD::isSignedIntSetCC(Cond)) {
3198 MinVal = 1ULL << (OperandBitSize-1);
3199 if (OperandBitSize != 1) // Avoid X >> 64, which is undefined.
3200 MaxVal = ~0ULL >> (65-OperandBitSize);
3205 MaxVal = ~0ULL >> (64-OperandBitSize);
3208 // Canonicalize GE/LE comparisons to use GT/LT comparisons.
3209 if (Cond == ISD::SETGE || Cond == ISD::SETUGE) {
3210 if (C1 == MinVal) return DAG.getConstant(1, VT); // X >= MIN --> true
3211 --C1; // X >= C0 --> X > (C0-1)
3212 return DAG.getSetCC(VT, N0, DAG.getConstant(C1, N1.getValueType()),
3213 (Cond == ISD::SETGE) ? ISD::SETGT : ISD::SETUGT);
3216 if (Cond == ISD::SETLE || Cond == ISD::SETULE) {
3217 if (C1 == MaxVal) return DAG.getConstant(1, VT); // X <= MAX --> true
3218 ++C1; // X <= C0 --> X < (C0+1)
3219 return DAG.getSetCC(VT, N0, DAG.getConstant(C1, N1.getValueType()),
3220 (Cond == ISD::SETLE) ? ISD::SETLT : ISD::SETULT);
3223 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MinVal)
3224 return DAG.getConstant(0, VT); // X < MIN --> false
3226 // Canonicalize setgt X, Min --> setne X, Min
3227 if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MinVal)
3228 return DAG.getSetCC(VT, N0, N1, ISD::SETNE);
3229 // Canonicalize setlt X, Max --> setne X, Max
3230 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MaxVal)
3231 return DAG.getSetCC(VT, N0, N1, ISD::SETNE);
3233 // If we have setult X, 1, turn it into seteq X, 0
3234 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MinVal+1)
3235 return DAG.getSetCC(VT, N0, DAG.getConstant(MinVal, N0.getValueType()),
3237 // If we have setugt X, Max-1, turn it into seteq X, Max
3238 else if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MaxVal-1)
3239 return DAG.getSetCC(VT, N0, DAG.getConstant(MaxVal, N0.getValueType()),
3242 // If we have "setcc X, C0", check to see if we can shrink the immediate
3245 // SETUGT X, SINTMAX -> SETLT X, 0
3246 if (Cond == ISD::SETUGT && OperandBitSize != 1 &&
3247 C1 == (~0ULL >> (65-OperandBitSize)))
3248 return DAG.getSetCC(VT, N0, DAG.getConstant(0, N1.getValueType()),
3251 // FIXME: Implement the rest of these.
3253 // Fold bit comparisons when we can.
3254 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
3255 VT == N0.getValueType() && N0.getOpcode() == ISD::AND)
3256 if (ConstantSDNode *AndRHS =
3257 dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
3258 if (Cond == ISD::SETNE && C1 == 0) {// (X & 8) != 0 --> (X & 8) >> 3
3259 // Perform the xform if the AND RHS is a single bit.
3260 if ((AndRHS->getValue() & (AndRHS->getValue()-1)) == 0) {
3261 return DAG.getNode(ISD::SRL, VT, N0,
3262 DAG.getConstant(Log2_64(AndRHS->getValue()),
3263 TLI.getShiftAmountTy()));
3265 } else if (Cond == ISD::SETEQ && C1 == AndRHS->getValue()) {
3266 // (X & 8) == 8 --> (X & 8) >> 3
3267 // Perform the xform if C1 is a single bit.
3268 if ((C1 & (C1-1)) == 0) {
3269 return DAG.getNode(ISD::SRL, VT, N0,
3270 DAG.getConstant(Log2_64(C1),TLI.getShiftAmountTy()));
3275 } else if (isa<ConstantSDNode>(N0.Val)) {
3276 // Ensure that the constant occurs on the RHS.
3277 return DAG.getSetCC(VT, N1, N0, ISD::getSetCCSwappedOperands(Cond));
3280 if (ConstantFPSDNode *N0C = dyn_cast<ConstantFPSDNode>(N0.Val))
3281 if (ConstantFPSDNode *N1C = dyn_cast<ConstantFPSDNode>(N1.Val)) {
3282 double C0 = N0C->getValue(), C1 = N1C->getValue();
3285 default: break; // FIXME: Implement the rest of these!
3286 case ISD::SETEQ: return DAG.getConstant(C0 == C1, VT);
3287 case ISD::SETNE: return DAG.getConstant(C0 != C1, VT);
3288 case ISD::SETLT: return DAG.getConstant(C0 < C1, VT);
3289 case ISD::SETGT: return DAG.getConstant(C0 > C1, VT);
3290 case ISD::SETLE: return DAG.getConstant(C0 <= C1, VT);
3291 case ISD::SETGE: return DAG.getConstant(C0 >= C1, VT);
3294 // Ensure that the constant occurs on the RHS.
3295 return DAG.getSetCC(VT, N1, N0, ISD::getSetCCSwappedOperands(Cond));
3299 // We can always fold X == Y for integer setcc's.
3300 if (MVT::isInteger(N0.getValueType()))
3301 return DAG.getConstant(ISD::isTrueWhenEqual(Cond), VT);
3302 unsigned UOF = ISD::getUnorderedFlavor(Cond);
3303 if (UOF == 2) // FP operators that are undefined on NaNs.
3304 return DAG.getConstant(ISD::isTrueWhenEqual(Cond), VT);
3305 if (UOF == unsigned(ISD::isTrueWhenEqual(Cond)))
3306 return DAG.getConstant(UOF, VT);
3307 // Otherwise, we can't fold it. However, we can simplify it to SETUO/SETO
3308 // if it is not already.
3309 ISD::CondCode NewCond = UOF == 0 ? ISD::SETO : ISD::SETUO;
3310 if (NewCond != Cond)
3311 return DAG.getSetCC(VT, N0, N1, NewCond);
3314 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
3315 MVT::isInteger(N0.getValueType())) {
3316 if (N0.getOpcode() == ISD::ADD || N0.getOpcode() == ISD::SUB ||
3317 N0.getOpcode() == ISD::XOR) {
3318 // Simplify (X+Y) == (X+Z) --> Y == Z
3319 if (N0.getOpcode() == N1.getOpcode()) {
3320 if (N0.getOperand(0) == N1.getOperand(0))
3321 return DAG.getSetCC(VT, N0.getOperand(1), N1.getOperand(1), Cond);
3322 if (N0.getOperand(1) == N1.getOperand(1))
3323 return DAG.getSetCC(VT, N0.getOperand(0), N1.getOperand(0), Cond);
3324 if (isCommutativeBinOp(N0.getOpcode())) {
3325 // If X op Y == Y op X, try other combinations.
3326 if (N0.getOperand(0) == N1.getOperand(1))
3327 return DAG.getSetCC(VT, N0.getOperand(1), N1.getOperand(0), Cond);
3328 if (N0.getOperand(1) == N1.getOperand(0))
3329 return DAG.getSetCC(VT, N0.getOperand(0), N1.getOperand(1), Cond);
3333 if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(N1)) {
3334 if (ConstantSDNode *LHSR = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
3335 // Turn (X+C1) == C2 --> X == C2-C1
3336 if (N0.getOpcode() == ISD::ADD && N0.Val->hasOneUse()) {
3337 return DAG.getSetCC(VT, N0.getOperand(0),
3338 DAG.getConstant(RHSC->getValue()-LHSR->getValue(),
3339 N0.getValueType()), Cond);
3342 // Turn (X^C1) == C2 into X == C1^C2 iff X&~C1 = 0.
3343 if (N0.getOpcode() == ISD::XOR)
3344 // If we know that all of the inverted bits are zero, don't bother
3345 // performing the inversion.
3346 if (TLI.MaskedValueIsZero(N0.getOperand(0), ~LHSR->getValue()))
3347 return DAG.getSetCC(VT, N0.getOperand(0),
3348 DAG.getConstant(LHSR->getValue()^RHSC->getValue(),
3349 N0.getValueType()), Cond);
3352 // Turn (C1-X) == C2 --> X == C1-C2
3353 if (ConstantSDNode *SUBC = dyn_cast<ConstantSDNode>(N0.getOperand(0))) {
3354 if (N0.getOpcode() == ISD::SUB && N0.Val->hasOneUse()) {
3355 return DAG.getSetCC(VT, N0.getOperand(1),
3356 DAG.getConstant(SUBC->getValue()-RHSC->getValue(),
3357 N0.getValueType()), Cond);
3362 // Simplify (X+Z) == X --> Z == 0
3363 if (N0.getOperand(0) == N1)
3364 return DAG.getSetCC(VT, N0.getOperand(1),
3365 DAG.getConstant(0, N0.getValueType()), Cond);
3366 if (N0.getOperand(1) == N1) {
3367 if (isCommutativeBinOp(N0.getOpcode()))
3368 return DAG.getSetCC(VT, N0.getOperand(0),
3369 DAG.getConstant(0, N0.getValueType()), Cond);
3371 assert(N0.getOpcode() == ISD::SUB && "Unexpected operation!");
3372 // (Z-X) == X --> Z == X<<1
3373 SDOperand SH = DAG.getNode(ISD::SHL, N1.getValueType(),
3375 DAG.getConstant(1,TLI.getShiftAmountTy()));
3376 AddToWorkList(SH.Val);
3377 return DAG.getSetCC(VT, N0.getOperand(0), SH, Cond);
3382 if (N1.getOpcode() == ISD::ADD || N1.getOpcode() == ISD::SUB ||
3383 N1.getOpcode() == ISD::XOR) {
3384 // Simplify X == (X+Z) --> Z == 0
3385 if (N1.getOperand(0) == N0) {
3386 return DAG.getSetCC(VT, N1.getOperand(1),
3387 DAG.getConstant(0, N1.getValueType()), Cond);
3388 } else if (N1.getOperand(1) == N0) {
3389 if (isCommutativeBinOp(N1.getOpcode())) {
3390 return DAG.getSetCC(VT, N1.getOperand(0),
3391 DAG.getConstant(0, N1.getValueType()), Cond);
3393 assert(N1.getOpcode() == ISD::SUB && "Unexpected operation!");
3394 // X == (Z-X) --> X<<1 == Z
3395 SDOperand SH = DAG.getNode(ISD::SHL, N1.getValueType(), N0,
3396 DAG.getConstant(1,TLI.getShiftAmountTy()));
3397 AddToWorkList(SH.Val);
3398 return DAG.getSetCC(VT, SH, N1.getOperand(0), Cond);
3404 // Fold away ALL boolean setcc's.
3406 if (N0.getValueType() == MVT::i1 && foldBooleans) {
3408 default: assert(0 && "Unknown integer setcc!");
3409 case ISD::SETEQ: // X == Y -> (X^Y)^1
3410 Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, N1);
3411 N0 = DAG.getNode(ISD::XOR, MVT::i1, Temp, DAG.getConstant(1, MVT::i1));
3412 AddToWorkList(Temp.Val);
3414 case ISD::SETNE: // X != Y --> (X^Y)
3415 N0 = DAG.getNode(ISD::XOR, MVT::i1, N0, N1);
3417 case ISD::SETGT: // X >s Y --> X == 0 & Y == 1 --> X^1 & Y
3418 case ISD::SETULT: // X <u Y --> X == 0 & Y == 1 --> X^1 & Y
3419 Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, DAG.getConstant(1, MVT::i1));
3420 N0 = DAG.getNode(ISD::AND, MVT::i1, N1, Temp);
3421 AddToWorkList(Temp.Val);
3423 case ISD::SETLT: // X <s Y --> X == 1 & Y == 0 --> Y^1 & X
3424 case ISD::SETUGT: // X >u Y --> X == 1 & Y == 0 --> Y^1 & X
3425 Temp = DAG.getNode(ISD::XOR, MVT::i1, N1, DAG.getConstant(1, MVT::i1));
3426 N0 = DAG.getNode(ISD::AND, MVT::i1, N0, Temp);
3427 AddToWorkList(Temp.Val);
3429 case ISD::SETULE: // X <=u Y --> X == 0 | Y == 1 --> X^1 | Y
3430 case ISD::SETGE: // X >=s Y --> X == 0 | Y == 1 --> X^1 | Y
3431 Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, DAG.getConstant(1, MVT::i1));
3432 N0 = DAG.getNode(ISD::OR, MVT::i1, N1, Temp);
3433 AddToWorkList(Temp.Val);
3435 case ISD::SETUGE: // X >=u Y --> X == 1 | Y == 0 --> Y^1 | X
3436 case ISD::SETLE: // X <=s Y --> X == 1 | Y == 0 --> Y^1 | X
3437 Temp = DAG.getNode(ISD::XOR, MVT::i1, N1, DAG.getConstant(1, MVT::i1));
3438 N0 = DAG.getNode(ISD::OR, MVT::i1, N0, Temp);
3441 if (VT != MVT::i1) {
3442 AddToWorkList(N0.Val);
3443 // FIXME: If running after legalize, we probably can't do this.
3444 N0 = DAG.getNode(ISD::ZERO_EXTEND, VT, N0);
3449 // Could not fold it.
3453 /// BuildSDIVSequence - Given an ISD::SDIV node expressing a divide by constant,
3454 /// return a DAG expression to select that will generate the same value by
3455 /// multiplying by a magic number. See:
3456 /// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
3457 SDOperand DAGCombiner::BuildSDIV(SDNode *N) {
3458 std::vector<SDNode*> Built;
3459 SDOperand S = TLI.BuildSDIV(N, DAG, &Built);
3461 for (std::vector<SDNode*>::iterator ii = Built.begin(), ee = Built.end();
3467 /// BuildUDIVSequence - Given an ISD::UDIV node expressing a divide by constant,
3468 /// return a DAG expression to select that will generate the same value by
3469 /// multiplying by a magic number. See:
3470 /// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
3471 SDOperand DAGCombiner::BuildUDIV(SDNode *N) {
3472 std::vector<SDNode*> Built;
3473 SDOperand S = TLI.BuildUDIV(N, DAG, &Built);
3475 for (std::vector<SDNode*>::iterator ii = Built.begin(), ee = Built.end();
3481 // SelectionDAG::Combine - This is the entry point for the file.
3483 void SelectionDAG::Combine(bool RunningAfterLegalize) {
3484 /// run - This is the main entry point to this class.
3486 DAGCombiner(*this).Run(RunningAfterLegalize);