1 //===- InstructionSimplify.cpp - Fold instruction operands ----------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements routines for folding instructions into simpler forms
11 // that do not require creating new instructions. This does constant folding
12 // ("add i32 1, 1" -> "2") but can also handle non-constant operands, either
13 // returning a constant ("and i32 %x, 0" -> "0") or an already existing value
14 // ("and i32 %x, %x" -> "%x"). All operands are assumed to have already been
15 // simplified: This is usually true and assuming it simplifies the logic (if
16 // they have not been simplified then results are correct but maybe suboptimal).
18 //===----------------------------------------------------------------------===//
20 #define DEBUG_TYPE "instsimplify"
21 #include "llvm/Analysis/InstructionSimplify.h"
22 #include "llvm/ADT/SetVector.h"
23 #include "llvm/ADT/Statistic.h"
24 #include "llvm/Analysis/AliasAnalysis.h"
25 #include "llvm/Analysis/ConstantFolding.h"
26 #include "llvm/Analysis/Dominators.h"
27 #include "llvm/Analysis/ValueTracking.h"
28 #include "llvm/IR/DataLayout.h"
29 #include "llvm/IR/GlobalAlias.h"
30 #include "llvm/IR/Operator.h"
31 #include "llvm/Support/ConstantRange.h"
32 #include "llvm/Support/GetElementPtrTypeIterator.h"
33 #include "llvm/Support/PatternMatch.h"
34 #include "llvm/Support/ValueHandle.h"
36 using namespace llvm::PatternMatch;
38 enum { RecursionLimit = 3 };
40 STATISTIC(NumExpand, "Number of expansions");
41 STATISTIC(NumFactor , "Number of factorizations");
42 STATISTIC(NumReassoc, "Number of reassociations");
46 const TargetLibraryInfo *TLI;
47 const DominatorTree *DT;
49 Query(const DataLayout *td, const TargetLibraryInfo *tli,
50 const DominatorTree *dt) : TD(td), TLI(tli), DT(dt) {}
53 static Value *SimplifyAndInst(Value *, Value *, const Query &, unsigned);
54 static Value *SimplifyBinOp(unsigned, Value *, Value *, const Query &,
56 static Value *SimplifyCmpInst(unsigned, Value *, Value *, const Query &,
58 static Value *SimplifyOrInst(Value *, Value *, const Query &, unsigned);
59 static Value *SimplifyXorInst(Value *, Value *, const Query &, unsigned);
60 static Value *SimplifyTruncInst(Value *, Type *, const Query &, unsigned);
62 /// getFalse - For a boolean type, or a vector of boolean type, return false, or
63 /// a vector with every element false, as appropriate for the type.
64 static Constant *getFalse(Type *Ty) {
65 assert(Ty->getScalarType()->isIntegerTy(1) &&
66 "Expected i1 type or a vector of i1!");
67 return Constant::getNullValue(Ty);
70 /// getTrue - For a boolean type, or a vector of boolean type, return true, or
71 /// a vector with every element true, as appropriate for the type.
72 static Constant *getTrue(Type *Ty) {
73 assert(Ty->getScalarType()->isIntegerTy(1) &&
74 "Expected i1 type or a vector of i1!");
75 return Constant::getAllOnesValue(Ty);
78 /// isSameCompare - Is V equivalent to the comparison "LHS Pred RHS"?
79 static bool isSameCompare(Value *V, CmpInst::Predicate Pred, Value *LHS,
81 CmpInst *Cmp = dyn_cast<CmpInst>(V);
84 CmpInst::Predicate CPred = Cmp->getPredicate();
85 Value *CLHS = Cmp->getOperand(0), *CRHS = Cmp->getOperand(1);
86 if (CPred == Pred && CLHS == LHS && CRHS == RHS)
88 return CPred == CmpInst::getSwappedPredicate(Pred) && CLHS == RHS &&
92 /// ValueDominatesPHI - Does the given value dominate the specified phi node?
93 static bool ValueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
94 Instruction *I = dyn_cast<Instruction>(V);
96 // Arguments and constants dominate all instructions.
99 // If we are processing instructions (and/or basic blocks) that have not been
100 // fully added to a function, the parent nodes may still be null. Simply
101 // return the conservative answer in these cases.
102 if (!I->getParent() || !P->getParent() || !I->getParent()->getParent())
105 // If we have a DominatorTree then do a precise test.
107 if (!DT->isReachableFromEntry(P->getParent()))
109 if (!DT->isReachableFromEntry(I->getParent()))
111 return DT->dominates(I, P);
114 // Otherwise, if the instruction is in the entry block, and is not an invoke,
115 // then it obviously dominates all phi nodes.
116 if (I->getParent() == &I->getParent()->getParent()->getEntryBlock() &&
123 /// ExpandBinOp - Simplify "A op (B op' C)" by distributing op over op', turning
124 /// it into "(A op B) op' (A op C)". Here "op" is given by Opcode and "op'" is
125 /// given by OpcodeToExpand, while "A" corresponds to LHS and "B op' C" to RHS.
126 /// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)".
127 /// Returns the simplified value, or null if no simplification was performed.
128 static Value *ExpandBinOp(unsigned Opcode, Value *LHS, Value *RHS,
129 unsigned OpcToExpand, const Query &Q,
130 unsigned MaxRecurse) {
131 Instruction::BinaryOps OpcodeToExpand = (Instruction::BinaryOps)OpcToExpand;
132 // Recursion is always used, so bail out at once if we already hit the limit.
136 // Check whether the expression has the form "(A op' B) op C".
137 if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS))
138 if (Op0->getOpcode() == OpcodeToExpand) {
139 // It does! Try turning it into "(A op C) op' (B op C)".
140 Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS;
141 // Do "A op C" and "B op C" both simplify?
142 if (Value *L = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse))
143 if (Value *R = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
144 // They do! Return "L op' R" if it simplifies or is already available.
145 // If "L op' R" equals "A op' B" then "L op' R" is just the LHS.
146 if ((L == A && R == B) || (Instruction::isCommutative(OpcodeToExpand)
147 && L == B && R == A)) {
151 // Otherwise return "L op' R" if it simplifies.
152 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
159 // Check whether the expression has the form "A op (B op' C)".
160 if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS))
161 if (Op1->getOpcode() == OpcodeToExpand) {
162 // It does! Try turning it into "(A op B) op' (A op C)".
163 Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1);
164 // Do "A op B" and "A op C" both simplify?
165 if (Value *L = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse))
166 if (Value *R = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse)) {
167 // They do! Return "L op' R" if it simplifies or is already available.
168 // If "L op' R" equals "B op' C" then "L op' R" is just the RHS.
169 if ((L == B && R == C) || (Instruction::isCommutative(OpcodeToExpand)
170 && L == C && R == B)) {
174 // Otherwise return "L op' R" if it simplifies.
175 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
185 /// FactorizeBinOp - Simplify "LHS Opcode RHS" by factorizing out a common term
186 /// using the operation OpCodeToExtract. For example, when Opcode is Add and
187 /// OpCodeToExtract is Mul then this tries to turn "(A*B)+(A*C)" into "A*(B+C)".
188 /// Returns the simplified value, or null if no simplification was performed.
189 static Value *FactorizeBinOp(unsigned Opcode, Value *LHS, Value *RHS,
190 unsigned OpcToExtract, const Query &Q,
191 unsigned MaxRecurse) {
192 Instruction::BinaryOps OpcodeToExtract = (Instruction::BinaryOps)OpcToExtract;
193 // Recursion is always used, so bail out at once if we already hit the limit.
197 BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
198 BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
200 if (!Op0 || Op0->getOpcode() != OpcodeToExtract ||
201 !Op1 || Op1->getOpcode() != OpcodeToExtract)
204 // The expression has the form "(A op' B) op (C op' D)".
205 Value *A = Op0->getOperand(0), *B = Op0->getOperand(1);
206 Value *C = Op1->getOperand(0), *D = Op1->getOperand(1);
208 // Use left distributivity, i.e. "X op' (Y op Z) = (X op' Y) op (X op' Z)".
209 // Does the instruction have the form "(A op' B) op (A op' D)" or, in the
210 // commutative case, "(A op' B) op (C op' A)"?
211 if (A == C || (Instruction::isCommutative(OpcodeToExtract) && A == D)) {
212 Value *DD = A == C ? D : C;
213 // Form "A op' (B op DD)" if it simplifies completely.
214 // Does "B op DD" simplify?
215 if (Value *V = SimplifyBinOp(Opcode, B, DD, Q, MaxRecurse)) {
216 // It does! Return "A op' V" if it simplifies or is already available.
217 // If V equals B then "A op' V" is just the LHS. If V equals DD then
218 // "A op' V" is just the RHS.
219 if (V == B || V == DD) {
221 return V == B ? LHS : RHS;
223 // Otherwise return "A op' V" if it simplifies.
224 if (Value *W = SimplifyBinOp(OpcodeToExtract, A, V, Q, MaxRecurse)) {
231 // Use right distributivity, i.e. "(X op Y) op' Z = (X op' Z) op (Y op' Z)".
232 // Does the instruction have the form "(A op' B) op (C op' B)" or, in the
233 // commutative case, "(A op' B) op (B op' D)"?
234 if (B == D || (Instruction::isCommutative(OpcodeToExtract) && B == C)) {
235 Value *CC = B == D ? C : D;
236 // Form "(A op CC) op' B" if it simplifies completely..
237 // Does "A op CC" simplify?
238 if (Value *V = SimplifyBinOp(Opcode, A, CC, Q, MaxRecurse)) {
239 // It does! Return "V op' B" if it simplifies or is already available.
240 // If V equals A then "V op' B" is just the LHS. If V equals CC then
241 // "V op' B" is just the RHS.
242 if (V == A || V == CC) {
244 return V == A ? LHS : RHS;
246 // Otherwise return "V op' B" if it simplifies.
247 if (Value *W = SimplifyBinOp(OpcodeToExtract, V, B, Q, MaxRecurse)) {
257 /// SimplifyAssociativeBinOp - Generic simplifications for associative binary
258 /// operations. Returns the simpler value, or null if none was found.
259 static Value *SimplifyAssociativeBinOp(unsigned Opc, Value *LHS, Value *RHS,
260 const Query &Q, unsigned MaxRecurse) {
261 Instruction::BinaryOps Opcode = (Instruction::BinaryOps)Opc;
262 assert(Instruction::isAssociative(Opcode) && "Not an associative operation!");
264 // Recursion is always used, so bail out at once if we already hit the limit.
268 BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
269 BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
271 // Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely.
272 if (Op0 && Op0->getOpcode() == Opcode) {
273 Value *A = Op0->getOperand(0);
274 Value *B = Op0->getOperand(1);
277 // Does "B op C" simplify?
278 if (Value *V = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
279 // It does! Return "A op V" if it simplifies or is already available.
280 // If V equals B then "A op V" is just the LHS.
281 if (V == B) return LHS;
282 // Otherwise return "A op V" if it simplifies.
283 if (Value *W = SimplifyBinOp(Opcode, A, V, Q, MaxRecurse)) {
290 // Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely.
291 if (Op1 && Op1->getOpcode() == Opcode) {
293 Value *B = Op1->getOperand(0);
294 Value *C = Op1->getOperand(1);
296 // Does "A op B" simplify?
297 if (Value *V = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse)) {
298 // It does! Return "V op C" if it simplifies or is already available.
299 // If V equals B then "V op C" is just the RHS.
300 if (V == B) return RHS;
301 // Otherwise return "V op C" if it simplifies.
302 if (Value *W = SimplifyBinOp(Opcode, V, C, Q, MaxRecurse)) {
309 // The remaining transforms require commutativity as well as associativity.
310 if (!Instruction::isCommutative(Opcode))
313 // Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely.
314 if (Op0 && Op0->getOpcode() == Opcode) {
315 Value *A = Op0->getOperand(0);
316 Value *B = Op0->getOperand(1);
319 // Does "C op A" simplify?
320 if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
321 // It does! Return "V op B" if it simplifies or is already available.
322 // If V equals A then "V op B" is just the LHS.
323 if (V == A) return LHS;
324 // Otherwise return "V op B" if it simplifies.
325 if (Value *W = SimplifyBinOp(Opcode, V, B, Q, MaxRecurse)) {
332 // Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely.
333 if (Op1 && Op1->getOpcode() == Opcode) {
335 Value *B = Op1->getOperand(0);
336 Value *C = Op1->getOperand(1);
338 // Does "C op A" simplify?
339 if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
340 // It does! Return "B op V" if it simplifies or is already available.
341 // If V equals C then "B op V" is just the RHS.
342 if (V == C) return RHS;
343 // Otherwise return "B op V" if it simplifies.
344 if (Value *W = SimplifyBinOp(Opcode, B, V, Q, MaxRecurse)) {
354 /// ThreadBinOpOverSelect - In the case of a binary operation with a select
355 /// instruction as an operand, try to simplify the binop by seeing whether
356 /// evaluating it on both branches of the select results in the same value.
357 /// Returns the common value if so, otherwise returns null.
358 static Value *ThreadBinOpOverSelect(unsigned Opcode, Value *LHS, Value *RHS,
359 const Query &Q, unsigned MaxRecurse) {
360 // Recursion is always used, so bail out at once if we already hit the limit.
365 if (isa<SelectInst>(LHS)) {
366 SI = cast<SelectInst>(LHS);
368 assert(isa<SelectInst>(RHS) && "No select instruction operand!");
369 SI = cast<SelectInst>(RHS);
372 // Evaluate the BinOp on the true and false branches of the select.
376 TV = SimplifyBinOp(Opcode, SI->getTrueValue(), RHS, Q, MaxRecurse);
377 FV = SimplifyBinOp(Opcode, SI->getFalseValue(), RHS, Q, MaxRecurse);
379 TV = SimplifyBinOp(Opcode, LHS, SI->getTrueValue(), Q, MaxRecurse);
380 FV = SimplifyBinOp(Opcode, LHS, SI->getFalseValue(), Q, MaxRecurse);
383 // If they simplified to the same value, then return the common value.
384 // If they both failed to simplify then return null.
388 // If one branch simplified to undef, return the other one.
389 if (TV && isa<UndefValue>(TV))
391 if (FV && isa<UndefValue>(FV))
394 // If applying the operation did not change the true and false select values,
395 // then the result of the binop is the select itself.
396 if (TV == SI->getTrueValue() && FV == SI->getFalseValue())
399 // If one branch simplified and the other did not, and the simplified
400 // value is equal to the unsimplified one, return the simplified value.
401 // For example, select (cond, X, X & Z) & Z -> X & Z.
402 if ((FV && !TV) || (TV && !FV)) {
403 // Check that the simplified value has the form "X op Y" where "op" is the
404 // same as the original operation.
405 Instruction *Simplified = dyn_cast<Instruction>(FV ? FV : TV);
406 if (Simplified && Simplified->getOpcode() == Opcode) {
407 // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS".
408 // We already know that "op" is the same as for the simplified value. See
409 // if the operands match too. If so, return the simplified value.
410 Value *UnsimplifiedBranch = FV ? SI->getTrueValue() : SI->getFalseValue();
411 Value *UnsimplifiedLHS = SI == LHS ? UnsimplifiedBranch : LHS;
412 Value *UnsimplifiedRHS = SI == LHS ? RHS : UnsimplifiedBranch;
413 if (Simplified->getOperand(0) == UnsimplifiedLHS &&
414 Simplified->getOperand(1) == UnsimplifiedRHS)
416 if (Simplified->isCommutative() &&
417 Simplified->getOperand(1) == UnsimplifiedLHS &&
418 Simplified->getOperand(0) == UnsimplifiedRHS)
426 /// ThreadCmpOverSelect - In the case of a comparison with a select instruction,
427 /// try to simplify the comparison by seeing whether both branches of the select
428 /// result in the same value. Returns the common value if so, otherwise returns
430 static Value *ThreadCmpOverSelect(CmpInst::Predicate Pred, Value *LHS,
431 Value *RHS, const Query &Q,
432 unsigned MaxRecurse) {
433 // Recursion is always used, so bail out at once if we already hit the limit.
437 // Make sure the select is on the LHS.
438 if (!isa<SelectInst>(LHS)) {
440 Pred = CmpInst::getSwappedPredicate(Pred);
442 assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!");
443 SelectInst *SI = cast<SelectInst>(LHS);
444 Value *Cond = SI->getCondition();
445 Value *TV = SI->getTrueValue();
446 Value *FV = SI->getFalseValue();
448 // Now that we have "cmp select(Cond, TV, FV), RHS", analyse it.
449 // Does "cmp TV, RHS" simplify?
450 Value *TCmp = SimplifyCmpInst(Pred, TV, RHS, Q, MaxRecurse);
452 // It not only simplified, it simplified to the select condition. Replace
454 TCmp = getTrue(Cond->getType());
456 // It didn't simplify. However if "cmp TV, RHS" is equal to the select
457 // condition then we can replace it with 'true'. Otherwise give up.
458 if (!isSameCompare(Cond, Pred, TV, RHS))
460 TCmp = getTrue(Cond->getType());
463 // Does "cmp FV, RHS" simplify?
464 Value *FCmp = SimplifyCmpInst(Pred, FV, RHS, Q, MaxRecurse);
466 // It not only simplified, it simplified to the select condition. Replace
468 FCmp = getFalse(Cond->getType());
470 // It didn't simplify. However if "cmp FV, RHS" is equal to the select
471 // condition then we can replace it with 'false'. Otherwise give up.
472 if (!isSameCompare(Cond, Pred, FV, RHS))
474 FCmp = getFalse(Cond->getType());
477 // If both sides simplified to the same value, then use it as the result of
478 // the original comparison.
482 // The remaining cases only make sense if the select condition has the same
483 // type as the result of the comparison, so bail out if this is not so.
484 if (Cond->getType()->isVectorTy() != RHS->getType()->isVectorTy())
486 // If the false value simplified to false, then the result of the compare
487 // is equal to "Cond && TCmp". This also catches the case when the false
488 // value simplified to false and the true value to true, returning "Cond".
489 if (match(FCmp, m_Zero()))
490 if (Value *V = SimplifyAndInst(Cond, TCmp, Q, MaxRecurse))
492 // If the true value simplified to true, then the result of the compare
493 // is equal to "Cond || FCmp".
494 if (match(TCmp, m_One()))
495 if (Value *V = SimplifyOrInst(Cond, FCmp, Q, MaxRecurse))
497 // Finally, if the false value simplified to true and the true value to
498 // false, then the result of the compare is equal to "!Cond".
499 if (match(FCmp, m_One()) && match(TCmp, m_Zero()))
501 SimplifyXorInst(Cond, Constant::getAllOnesValue(Cond->getType()),
508 /// ThreadBinOpOverPHI - In the case of a binary operation with an operand that
509 /// is a PHI instruction, try to simplify the binop by seeing whether evaluating
510 /// it on the incoming phi values yields the same result for every value. If so
511 /// returns the common value, otherwise returns null.
512 static Value *ThreadBinOpOverPHI(unsigned Opcode, Value *LHS, Value *RHS,
513 const Query &Q, unsigned MaxRecurse) {
514 // Recursion is always used, so bail out at once if we already hit the limit.
519 if (isa<PHINode>(LHS)) {
520 PI = cast<PHINode>(LHS);
521 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
522 if (!ValueDominatesPHI(RHS, PI, Q.DT))
525 assert(isa<PHINode>(RHS) && "No PHI instruction operand!");
526 PI = cast<PHINode>(RHS);
527 // Bail out if LHS and the phi may be mutually interdependent due to a loop.
528 if (!ValueDominatesPHI(LHS, PI, Q.DT))
532 // Evaluate the BinOp on the incoming phi values.
533 Value *CommonValue = 0;
534 for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
535 Value *Incoming = PI->getIncomingValue(i);
536 // If the incoming value is the phi node itself, it can safely be skipped.
537 if (Incoming == PI) continue;
538 Value *V = PI == LHS ?
539 SimplifyBinOp(Opcode, Incoming, RHS, Q, MaxRecurse) :
540 SimplifyBinOp(Opcode, LHS, Incoming, Q, MaxRecurse);
541 // If the operation failed to simplify, or simplified to a different value
542 // to previously, then give up.
543 if (!V || (CommonValue && V != CommonValue))
551 /// ThreadCmpOverPHI - In the case of a comparison with a PHI instruction, try
552 /// try to simplify the comparison by seeing whether comparing with all of the
553 /// incoming phi values yields the same result every time. If so returns the
554 /// common result, otherwise returns null.
555 static Value *ThreadCmpOverPHI(CmpInst::Predicate Pred, Value *LHS, Value *RHS,
556 const Query &Q, unsigned MaxRecurse) {
557 // Recursion is always used, so bail out at once if we already hit the limit.
561 // Make sure the phi is on the LHS.
562 if (!isa<PHINode>(LHS)) {
564 Pred = CmpInst::getSwappedPredicate(Pred);
566 assert(isa<PHINode>(LHS) && "Not comparing with a phi instruction!");
567 PHINode *PI = cast<PHINode>(LHS);
569 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
570 if (!ValueDominatesPHI(RHS, PI, Q.DT))
573 // Evaluate the BinOp on the incoming phi values.
574 Value *CommonValue = 0;
575 for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
576 Value *Incoming = PI->getIncomingValue(i);
577 // If the incoming value is the phi node itself, it can safely be skipped.
578 if (Incoming == PI) continue;
579 Value *V = SimplifyCmpInst(Pred, Incoming, RHS, Q, MaxRecurse);
580 // If the operation failed to simplify, or simplified to a different value
581 // to previously, then give up.
582 if (!V || (CommonValue && V != CommonValue))
590 /// SimplifyAddInst - Given operands for an Add, see if we can
591 /// fold the result. If not, this returns null.
592 static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
593 const Query &Q, unsigned MaxRecurse) {
594 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
595 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
596 Constant *Ops[] = { CLHS, CRHS };
597 return ConstantFoldInstOperands(Instruction::Add, CLHS->getType(), Ops,
601 // Canonicalize the constant to the RHS.
605 // X + undef -> undef
606 if (match(Op1, m_Undef()))
610 if (match(Op1, m_Zero()))
617 if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) ||
618 match(Op0, m_Sub(m_Value(Y), m_Specific(Op1))))
621 // X + ~X -> -1 since ~X = -X-1
622 if (match(Op0, m_Not(m_Specific(Op1))) ||
623 match(Op1, m_Not(m_Specific(Op0))))
624 return Constant::getAllOnesValue(Op0->getType());
627 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
628 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
631 // Try some generic simplifications for associative operations.
632 if (Value *V = SimplifyAssociativeBinOp(Instruction::Add, Op0, Op1, Q,
636 // Mul distributes over Add. Try some generic simplifications based on this.
637 if (Value *V = FactorizeBinOp(Instruction::Add, Op0, Op1, Instruction::Mul,
641 // Threading Add over selects and phi nodes is pointless, so don't bother.
642 // Threading over the select in "A + select(cond, B, C)" means evaluating
643 // "A+B" and "A+C" and seeing if they are equal; but they are equal if and
644 // only if B and C are equal. If B and C are equal then (since we assume
645 // that operands have already been simplified) "select(cond, B, C)" should
646 // have been simplified to the common value of B and C already. Analysing
647 // "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly
648 // for threading over phi nodes.
653 Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
654 const DataLayout *TD, const TargetLibraryInfo *TLI,
655 const DominatorTree *DT) {
656 return ::SimplifyAddInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT),
660 /// \brief Compute the base pointer and cumulative constant offsets for V.
662 /// This strips all constant offsets off of V, leaving it the base pointer, and
663 /// accumulates the total constant offset applied in the returned constant. It
664 /// returns 0 if V is not a pointer, and returns the constant '0' if there are
665 /// no constant offsets applied.
666 static Constant *stripAndComputeConstantOffsets(const DataLayout &TD,
668 if (!V->getType()->isPointerTy())
671 unsigned IntPtrWidth = TD.getPointerSizeInBits();
672 APInt Offset = APInt::getNullValue(IntPtrWidth);
674 // Even though we don't look through PHI nodes, we could be called on an
675 // instruction in an unreachable block, which may be on a cycle.
676 SmallPtrSet<Value *, 4> Visited;
679 if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
680 if (!GEP->isInBounds() || !GEP->accumulateConstantOffset(TD, Offset))
682 V = GEP->getPointerOperand();
683 } else if (Operator::getOpcode(V) == Instruction::BitCast) {
684 V = cast<Operator>(V)->getOperand(0);
685 } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
686 if (GA->mayBeOverridden())
688 V = GA->getAliasee();
692 assert(V->getType()->isPointerTy() && "Unexpected operand type!");
693 } while (Visited.insert(V));
695 Type *IntPtrTy = TD.getIntPtrType(V->getContext());
696 return ConstantInt::get(IntPtrTy, Offset);
699 /// \brief Compute the constant difference between two pointer values.
700 /// If the difference is not a constant, returns zero.
701 static Constant *computePointerDifference(const DataLayout &TD,
702 Value *LHS, Value *RHS) {
703 Constant *LHSOffset = stripAndComputeConstantOffsets(TD, LHS);
706 Constant *RHSOffset = stripAndComputeConstantOffsets(TD, RHS);
710 // If LHS and RHS are not related via constant offsets to the same base
711 // value, there is nothing we can do here.
715 // Otherwise, the difference of LHS - RHS can be computed as:
717 // = (LHSOffset + Base) - (RHSOffset + Base)
718 // = LHSOffset - RHSOffset
719 return ConstantExpr::getSub(LHSOffset, RHSOffset);
722 /// SimplifySubInst - Given operands for a Sub, see if we can
723 /// fold the result. If not, this returns null.
724 static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
725 const Query &Q, unsigned MaxRecurse) {
726 if (Constant *CLHS = dyn_cast<Constant>(Op0))
727 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
728 Constant *Ops[] = { CLHS, CRHS };
729 return ConstantFoldInstOperands(Instruction::Sub, CLHS->getType(),
733 // X - undef -> undef
734 // undef - X -> undef
735 if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
736 return UndefValue::get(Op0->getType());
739 if (match(Op1, m_Zero()))
744 return Constant::getNullValue(Op0->getType());
749 if (match(Op0, m_Mul(m_Specific(Op1), m_ConstantInt<2>())) ||
750 match(Op0, m_Shl(m_Specific(Op1), m_One())))
753 // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
754 // For example, (X + Y) - Y -> X; (Y + X) - Y -> X
755 Value *Y = 0, *Z = Op1;
756 if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z
757 // See if "V === Y - Z" simplifies.
758 if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, Q, MaxRecurse-1))
759 // It does! Now see if "X + V" simplifies.
760 if (Value *W = SimplifyBinOp(Instruction::Add, X, V, Q, MaxRecurse-1)) {
761 // It does, we successfully reassociated!
765 // See if "V === X - Z" simplifies.
766 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
767 // It does! Now see if "Y + V" simplifies.
768 if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, Q, MaxRecurse-1)) {
769 // It does, we successfully reassociated!
775 // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
776 // For example, X - (X + 1) -> -1
778 if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z)
779 // See if "V === X - Y" simplifies.
780 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
781 // It does! Now see if "V - Z" simplifies.
782 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, Q, MaxRecurse-1)) {
783 // It does, we successfully reassociated!
787 // See if "V === X - Z" simplifies.
788 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
789 // It does! Now see if "V - Y" simplifies.
790 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, Q, MaxRecurse-1)) {
791 // It does, we successfully reassociated!
797 // Z - (X - Y) -> (Z - X) + Y if everything simplifies.
798 // For example, X - (X - Y) -> Y.
800 if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y)
801 // See if "V === Z - X" simplifies.
802 if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, Q, MaxRecurse-1))
803 // It does! Now see if "V + Y" simplifies.
804 if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, Q, MaxRecurse-1)) {
805 // It does, we successfully reassociated!
810 // trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies.
811 if (MaxRecurse && match(Op0, m_Trunc(m_Value(X))) &&
812 match(Op1, m_Trunc(m_Value(Y))))
813 if (X->getType() == Y->getType())
814 // See if "V === X - Y" simplifies.
815 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
816 // It does! Now see if "trunc V" simplifies.
817 if (Value *W = SimplifyTruncInst(V, Op0->getType(), Q, MaxRecurse-1))
818 // It does, return the simplified "trunc V".
821 // Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...).
822 if (Q.TD && match(Op0, m_PtrToInt(m_Value(X))) &&
823 match(Op1, m_PtrToInt(m_Value(Y))))
824 if (Constant *Result = computePointerDifference(*Q.TD, X, Y))
825 return ConstantExpr::getIntegerCast(Result, Op0->getType(), true);
827 // Mul distributes over Sub. Try some generic simplifications based on this.
828 if (Value *V = FactorizeBinOp(Instruction::Sub, Op0, Op1, Instruction::Mul,
833 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
834 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
837 // Threading Sub over selects and phi nodes is pointless, so don't bother.
838 // Threading over the select in "A - select(cond, B, C)" means evaluating
839 // "A-B" and "A-C" and seeing if they are equal; but they are equal if and
840 // only if B and C are equal. If B and C are equal then (since we assume
841 // that operands have already been simplified) "select(cond, B, C)" should
842 // have been simplified to the common value of B and C already. Analysing
843 // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly
844 // for threading over phi nodes.
849 Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
850 const DataLayout *TD, const TargetLibraryInfo *TLI,
851 const DominatorTree *DT) {
852 return ::SimplifySubInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT),
856 /// Given operands for an FAdd, see if we can fold the result. If not, this
858 static Value *SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
859 const Query &Q, unsigned MaxRecurse) {
860 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
861 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
862 Constant *Ops[] = { CLHS, CRHS };
863 return ConstantFoldInstOperands(Instruction::FAdd, CLHS->getType(),
867 // Canonicalize the constant to the RHS.
872 if (match(Op1, m_NegZero()))
875 // fadd X, 0 ==> X, when we know X is not -0
876 if (match(Op1, m_Zero()) &&
877 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
880 // fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
881 // where nnan and ninf have to occur at least once somewhere in this
884 if (match(Op1, m_FSub(m_AnyZero(), m_Specific(Op0))))
886 else if (match(Op0, m_FSub(m_AnyZero(), m_Specific(Op1))))
889 Instruction *FSub = cast<Instruction>(SubOp);
890 if ((FMF.noNaNs() || FSub->hasNoNaNs()) &&
891 (FMF.noInfs() || FSub->hasNoInfs()))
892 return Constant::getNullValue(Op0->getType());
898 /// Given operands for an FSub, see if we can fold the result. If not, this
900 static Value *SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
901 const Query &Q, unsigned MaxRecurse) {
902 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
903 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
904 Constant *Ops[] = { CLHS, CRHS };
905 return ConstantFoldInstOperands(Instruction::FSub, CLHS->getType(),
911 if (match(Op1, m_Zero()))
914 // fsub X, -0 ==> X, when we know X is not -0
915 if (match(Op1, m_NegZero()) &&
916 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
919 // fsub 0, (fsub -0.0, X) ==> X
921 if (match(Op0, m_AnyZero())) {
922 if (match(Op1, m_FSub(m_NegZero(), m_Value(X))))
924 if (FMF.noSignedZeros() && match(Op1, m_FSub(m_AnyZero(), m_Value(X))))
928 // fsub nnan ninf x, x ==> 0.0
929 if (FMF.noNaNs() && FMF.noInfs() && Op0 == Op1)
930 return Constant::getNullValue(Op0->getType());
935 /// Given the operands for an FMul, see if we can fold the result
936 static Value *SimplifyFMulInst(Value *Op0, Value *Op1,
939 unsigned MaxRecurse) {
940 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
941 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
942 Constant *Ops[] = { CLHS, CRHS };
943 return ConstantFoldInstOperands(Instruction::FMul, CLHS->getType(),
947 // Canonicalize the constant to the RHS.
952 if (match(Op1, m_FPOne()))
955 // fmul nnan nsz X, 0 ==> 0
956 if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZero()))
962 /// SimplifyMulInst - Given operands for a Mul, see if we can
963 /// fold the result. If not, this returns null.
964 static Value *SimplifyMulInst(Value *Op0, Value *Op1, const Query &Q,
965 unsigned MaxRecurse) {
966 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
967 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
968 Constant *Ops[] = { CLHS, CRHS };
969 return ConstantFoldInstOperands(Instruction::Mul, CLHS->getType(),
973 // Canonicalize the constant to the RHS.
978 if (match(Op1, m_Undef()))
979 return Constant::getNullValue(Op0->getType());
982 if (match(Op1, m_Zero()))
986 if (match(Op1, m_One()))
989 // (X / Y) * Y -> X if the division is exact.
991 if (match(Op0, m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y
992 match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0))))) // Y * (X / Y)
996 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
997 if (Value *V = SimplifyAndInst(Op0, Op1, Q, MaxRecurse-1))
1000 // Try some generic simplifications for associative operations.
1001 if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, Q,
1005 // Mul distributes over Add. Try some generic simplifications based on this.
1006 if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add,
1010 // If the operation is with the result of a select instruction, check whether
1011 // operating on either branch of the select always yields the same value.
1012 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1013 if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, Q,
1017 // If the operation is with the result of a phi instruction, check whether
1018 // operating on all incoming values of the phi always yields the same value.
1019 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1020 if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, Q,
1027 Value *llvm::SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
1028 const DataLayout *TD, const TargetLibraryInfo *TLI,
1029 const DominatorTree *DT) {
1030 return ::SimplifyFAddInst(Op0, Op1, FMF, Query (TD, TLI, DT), RecursionLimit);
1033 Value *llvm::SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
1034 const DataLayout *TD, const TargetLibraryInfo *TLI,
1035 const DominatorTree *DT) {
1036 return ::SimplifyFSubInst(Op0, Op1, FMF, Query (TD, TLI, DT), RecursionLimit);
1039 Value *llvm::SimplifyFMulInst(Value *Op0, Value *Op1,
1041 const DataLayout *TD,
1042 const TargetLibraryInfo *TLI,
1043 const DominatorTree *DT) {
1044 return ::SimplifyFMulInst(Op0, Op1, FMF, Query (TD, TLI, DT), RecursionLimit);
1047 Value *llvm::SimplifyMulInst(Value *Op0, Value *Op1, const DataLayout *TD,
1048 const TargetLibraryInfo *TLI,
1049 const DominatorTree *DT) {
1050 return ::SimplifyMulInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1053 /// SimplifyDiv - Given operands for an SDiv or UDiv, see if we can
1054 /// fold the result. If not, this returns null.
1055 static Value *SimplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
1056 const Query &Q, unsigned MaxRecurse) {
1057 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1058 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1059 Constant *Ops[] = { C0, C1 };
1060 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI);
1064 bool isSigned = Opcode == Instruction::SDiv;
1066 // X / undef -> undef
1067 if (match(Op1, m_Undef()))
1071 if (match(Op0, m_Undef()))
1072 return Constant::getNullValue(Op0->getType());
1074 // 0 / X -> 0, we don't need to preserve faults!
1075 if (match(Op0, m_Zero()))
1079 if (match(Op1, m_One()))
1082 if (Op0->getType()->isIntegerTy(1))
1083 // It can't be division by zero, hence it must be division by one.
1088 return ConstantInt::get(Op0->getType(), 1);
1090 // (X * Y) / Y -> X if the multiplication does not overflow.
1091 Value *X = 0, *Y = 0;
1092 if (match(Op0, m_Mul(m_Value(X), m_Value(Y))) && (X == Op1 || Y == Op1)) {
1093 if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1
1094 OverflowingBinaryOperator *Mul = cast<OverflowingBinaryOperator>(Op0);
1095 // If the Mul knows it does not overflow, then we are good to go.
1096 if ((isSigned && Mul->hasNoSignedWrap()) ||
1097 (!isSigned && Mul->hasNoUnsignedWrap()))
1099 // If X has the form X = A / Y then X * Y cannot overflow.
1100 if (BinaryOperator *Div = dyn_cast<BinaryOperator>(X))
1101 if (Div->getOpcode() == Opcode && Div->getOperand(1) == Y)
1105 // (X rem Y) / Y -> 0
1106 if ((isSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1107 (!isSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1108 return Constant::getNullValue(Op0->getType());
1110 // If the operation is with the result of a select instruction, check whether
1111 // operating on either branch of the select always yields the same value.
1112 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1113 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1116 // If the operation is with the result of a phi instruction, check whether
1117 // operating on all incoming values of the phi always yields the same value.
1118 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1119 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1125 /// SimplifySDivInst - Given operands for an SDiv, see if we can
1126 /// fold the result. If not, this returns null.
1127 static Value *SimplifySDivInst(Value *Op0, Value *Op1, const Query &Q,
1128 unsigned MaxRecurse) {
1129 if (Value *V = SimplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse))
1135 Value *llvm::SimplifySDivInst(Value *Op0, Value *Op1, const DataLayout *TD,
1136 const TargetLibraryInfo *TLI,
1137 const DominatorTree *DT) {
1138 return ::SimplifySDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1141 /// SimplifyUDivInst - Given operands for a UDiv, see if we can
1142 /// fold the result. If not, this returns null.
1143 static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const Query &Q,
1144 unsigned MaxRecurse) {
1145 if (Value *V = SimplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse))
1151 Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const DataLayout *TD,
1152 const TargetLibraryInfo *TLI,
1153 const DominatorTree *DT) {
1154 return ::SimplifyUDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1157 static Value *SimplifyFDivInst(Value *Op0, Value *Op1, const Query &Q,
1159 // undef / X -> undef (the undef could be a snan).
1160 if (match(Op0, m_Undef()))
1163 // X / undef -> undef
1164 if (match(Op1, m_Undef()))
1170 Value *llvm::SimplifyFDivInst(Value *Op0, Value *Op1, const DataLayout *TD,
1171 const TargetLibraryInfo *TLI,
1172 const DominatorTree *DT) {
1173 return ::SimplifyFDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1176 /// SimplifyRem - Given operands for an SRem or URem, see if we can
1177 /// fold the result. If not, this returns null.
1178 static Value *SimplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
1179 const Query &Q, unsigned MaxRecurse) {
1180 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1181 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1182 Constant *Ops[] = { C0, C1 };
1183 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI);
1187 // X % undef -> undef
1188 if (match(Op1, m_Undef()))
1192 if (match(Op0, m_Undef()))
1193 return Constant::getNullValue(Op0->getType());
1195 // 0 % X -> 0, we don't need to preserve faults!
1196 if (match(Op0, m_Zero()))
1199 // X % 0 -> undef, we don't need to preserve faults!
1200 if (match(Op1, m_Zero()))
1201 return UndefValue::get(Op0->getType());
1204 if (match(Op1, m_One()))
1205 return Constant::getNullValue(Op0->getType());
1207 if (Op0->getType()->isIntegerTy(1))
1208 // It can't be remainder by zero, hence it must be remainder by one.
1209 return Constant::getNullValue(Op0->getType());
1213 return Constant::getNullValue(Op0->getType());
1215 // If the operation is with the result of a select instruction, check whether
1216 // operating on either branch of the select always yields the same value.
1217 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1218 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1221 // If the operation is with the result of a phi instruction, check whether
1222 // operating on all incoming values of the phi always yields the same value.
1223 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1224 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1230 /// SimplifySRemInst - Given operands for an SRem, see if we can
1231 /// fold the result. If not, this returns null.
1232 static Value *SimplifySRemInst(Value *Op0, Value *Op1, const Query &Q,
1233 unsigned MaxRecurse) {
1234 if (Value *V = SimplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse))
1240 Value *llvm::SimplifySRemInst(Value *Op0, Value *Op1, const DataLayout *TD,
1241 const TargetLibraryInfo *TLI,
1242 const DominatorTree *DT) {
1243 return ::SimplifySRemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1246 /// SimplifyURemInst - Given operands for a URem, see if we can
1247 /// fold the result. If not, this returns null.
1248 static Value *SimplifyURemInst(Value *Op0, Value *Op1, const Query &Q,
1249 unsigned MaxRecurse) {
1250 if (Value *V = SimplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse))
1256 Value *llvm::SimplifyURemInst(Value *Op0, Value *Op1, const DataLayout *TD,
1257 const TargetLibraryInfo *TLI,
1258 const DominatorTree *DT) {
1259 return ::SimplifyURemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1262 static Value *SimplifyFRemInst(Value *Op0, Value *Op1, const Query &,
1264 // undef % X -> undef (the undef could be a snan).
1265 if (match(Op0, m_Undef()))
1268 // X % undef -> undef
1269 if (match(Op1, m_Undef()))
1275 Value *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, const DataLayout *TD,
1276 const TargetLibraryInfo *TLI,
1277 const DominatorTree *DT) {
1278 return ::SimplifyFRemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1281 /// SimplifyShift - Given operands for an Shl, LShr or AShr, see if we can
1282 /// fold the result. If not, this returns null.
1283 static Value *SimplifyShift(unsigned Opcode, Value *Op0, Value *Op1,
1284 const Query &Q, unsigned MaxRecurse) {
1285 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1286 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1287 Constant *Ops[] = { C0, C1 };
1288 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI);
1292 // 0 shift by X -> 0
1293 if (match(Op0, m_Zero()))
1296 // X shift by 0 -> X
1297 if (match(Op1, m_Zero()))
1300 // X shift by undef -> undef because it may shift by the bitwidth.
1301 if (match(Op1, m_Undef()))
1304 // Shifting by the bitwidth or more is undefined.
1305 if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1))
1306 if (CI->getValue().getLimitedValue() >=
1307 Op0->getType()->getScalarSizeInBits())
1308 return UndefValue::get(Op0->getType());
1310 // If the operation is with the result of a select instruction, check whether
1311 // operating on either branch of the select always yields the same value.
1312 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1313 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1316 // If the operation is with the result of a phi instruction, check whether
1317 // operating on all incoming values of the phi always yields the same value.
1318 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1319 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1325 /// SimplifyShlInst - Given operands for an Shl, see if we can
1326 /// fold the result. If not, this returns null.
1327 static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1328 const Query &Q, unsigned MaxRecurse) {
1329 if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse))
1333 if (match(Op0, m_Undef()))
1334 return Constant::getNullValue(Op0->getType());
1336 // (X >> A) << A -> X
1338 if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
1343 Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1344 const DataLayout *TD, const TargetLibraryInfo *TLI,
1345 const DominatorTree *DT) {
1346 return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT),
1350 /// SimplifyLShrInst - Given operands for an LShr, see if we can
1351 /// fold the result. If not, this returns null.
1352 static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1353 const Query &Q, unsigned MaxRecurse) {
1354 if (Value *V = SimplifyShift(Instruction::LShr, Op0, Op1, Q, MaxRecurse))
1358 if (match(Op0, m_Undef()))
1359 return Constant::getNullValue(Op0->getType());
1361 // (X << A) >> A -> X
1363 if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) &&
1364 cast<OverflowingBinaryOperator>(Op0)->hasNoUnsignedWrap())
1370 Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1371 const DataLayout *TD,
1372 const TargetLibraryInfo *TLI,
1373 const DominatorTree *DT) {
1374 return ::SimplifyLShrInst(Op0, Op1, isExact, Query (TD, TLI, DT),
1378 /// SimplifyAShrInst - Given operands for an AShr, see if we can
1379 /// fold the result. If not, this returns null.
1380 static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1381 const Query &Q, unsigned MaxRecurse) {
1382 if (Value *V = SimplifyShift(Instruction::AShr, Op0, Op1, Q, MaxRecurse))
1385 // all ones >>a X -> all ones
1386 if (match(Op0, m_AllOnes()))
1389 // undef >>a X -> all ones
1390 if (match(Op0, m_Undef()))
1391 return Constant::getAllOnesValue(Op0->getType());
1393 // (X << A) >> A -> X
1395 if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) &&
1396 cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap())
1402 Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1403 const DataLayout *TD,
1404 const TargetLibraryInfo *TLI,
1405 const DominatorTree *DT) {
1406 return ::SimplifyAShrInst(Op0, Op1, isExact, Query (TD, TLI, DT),
1410 /// SimplifyAndInst - Given operands for an And, see if we can
1411 /// fold the result. If not, this returns null.
1412 static Value *SimplifyAndInst(Value *Op0, Value *Op1, const Query &Q,
1413 unsigned MaxRecurse) {
1414 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1415 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1416 Constant *Ops[] = { CLHS, CRHS };
1417 return ConstantFoldInstOperands(Instruction::And, CLHS->getType(),
1421 // Canonicalize the constant to the RHS.
1422 std::swap(Op0, Op1);
1426 if (match(Op1, m_Undef()))
1427 return Constant::getNullValue(Op0->getType());
1434 if (match(Op1, m_Zero()))
1438 if (match(Op1, m_AllOnes()))
1441 // A & ~A = ~A & A = 0
1442 if (match(Op0, m_Not(m_Specific(Op1))) ||
1443 match(Op1, m_Not(m_Specific(Op0))))
1444 return Constant::getNullValue(Op0->getType());
1447 Value *A = 0, *B = 0;
1448 if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
1449 (A == Op1 || B == Op1))
1453 if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
1454 (A == Op0 || B == Op0))
1457 // A & (-A) = A if A is a power of two or zero.
1458 if (match(Op0, m_Neg(m_Specific(Op1))) ||
1459 match(Op1, m_Neg(m_Specific(Op0)))) {
1460 if (isKnownToBeAPowerOfTwo(Op0, /*OrZero*/true))
1462 if (isKnownToBeAPowerOfTwo(Op1, /*OrZero*/true))
1466 // Try some generic simplifications for associative operations.
1467 if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
1471 // And distributes over Or. Try some generic simplifications based on this.
1472 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1476 // And distributes over Xor. Try some generic simplifications based on this.
1477 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
1481 // Or distributes over And. Try some generic simplifications based on this.
1482 if (Value *V = FactorizeBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1486 // If the operation is with the result of a select instruction, check whether
1487 // operating on either branch of the select always yields the same value.
1488 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1489 if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
1493 // If the operation is with the result of a phi instruction, check whether
1494 // operating on all incoming values of the phi always yields the same value.
1495 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1496 if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
1503 Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const DataLayout *TD,
1504 const TargetLibraryInfo *TLI,
1505 const DominatorTree *DT) {
1506 return ::SimplifyAndInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1509 /// SimplifyOrInst - Given operands for an Or, see if we can
1510 /// fold the result. If not, this returns null.
1511 static Value *SimplifyOrInst(Value *Op0, Value *Op1, const Query &Q,
1512 unsigned MaxRecurse) {
1513 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1514 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1515 Constant *Ops[] = { CLHS, CRHS };
1516 return ConstantFoldInstOperands(Instruction::Or, CLHS->getType(),
1520 // Canonicalize the constant to the RHS.
1521 std::swap(Op0, Op1);
1525 if (match(Op1, m_Undef()))
1526 return Constant::getAllOnesValue(Op0->getType());
1533 if (match(Op1, m_Zero()))
1537 if (match(Op1, m_AllOnes()))
1540 // A | ~A = ~A | A = -1
1541 if (match(Op0, m_Not(m_Specific(Op1))) ||
1542 match(Op1, m_Not(m_Specific(Op0))))
1543 return Constant::getAllOnesValue(Op0->getType());
1546 Value *A = 0, *B = 0;
1547 if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
1548 (A == Op1 || B == Op1))
1552 if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
1553 (A == Op0 || B == Op0))
1556 // ~(A & ?) | A = -1
1557 if (match(Op0, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1558 (A == Op1 || B == Op1))
1559 return Constant::getAllOnesValue(Op1->getType());
1561 // A | ~(A & ?) = -1
1562 if (match(Op1, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1563 (A == Op0 || B == Op0))
1564 return Constant::getAllOnesValue(Op0->getType());
1566 // Try some generic simplifications for associative operations.
1567 if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
1571 // Or distributes over And. Try some generic simplifications based on this.
1572 if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
1576 // And distributes over Or. Try some generic simplifications based on this.
1577 if (Value *V = FactorizeBinOp(Instruction::Or, Op0, Op1, Instruction::And,
1581 // If the operation is with the result of a select instruction, check whether
1582 // operating on either branch of the select always yields the same value.
1583 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1584 if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
1588 // If the operation is with the result of a phi instruction, check whether
1589 // operating on all incoming values of the phi always yields the same value.
1590 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1591 if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
1597 Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const DataLayout *TD,
1598 const TargetLibraryInfo *TLI,
1599 const DominatorTree *DT) {
1600 return ::SimplifyOrInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1603 /// SimplifyXorInst - Given operands for a Xor, see if we can
1604 /// fold the result. If not, this returns null.
1605 static Value *SimplifyXorInst(Value *Op0, Value *Op1, const Query &Q,
1606 unsigned MaxRecurse) {
1607 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1608 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1609 Constant *Ops[] = { CLHS, CRHS };
1610 return ConstantFoldInstOperands(Instruction::Xor, CLHS->getType(),
1614 // Canonicalize the constant to the RHS.
1615 std::swap(Op0, Op1);
1618 // A ^ undef -> undef
1619 if (match(Op1, m_Undef()))
1623 if (match(Op1, m_Zero()))
1628 return Constant::getNullValue(Op0->getType());
1630 // A ^ ~A = ~A ^ A = -1
1631 if (match(Op0, m_Not(m_Specific(Op1))) ||
1632 match(Op1, m_Not(m_Specific(Op0))))
1633 return Constant::getAllOnesValue(Op0->getType());
1635 // Try some generic simplifications for associative operations.
1636 if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
1640 // And distributes over Xor. Try some generic simplifications based on this.
1641 if (Value *V = FactorizeBinOp(Instruction::Xor, Op0, Op1, Instruction::And,
1645 // Threading Xor over selects and phi nodes is pointless, so don't bother.
1646 // Threading over the select in "A ^ select(cond, B, C)" means evaluating
1647 // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
1648 // only if B and C are equal. If B and C are equal then (since we assume
1649 // that operands have already been simplified) "select(cond, B, C)" should
1650 // have been simplified to the common value of B and C already. Analysing
1651 // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
1652 // for threading over phi nodes.
1657 Value *llvm::SimplifyXorInst(Value *Op0, Value *Op1, const DataLayout *TD,
1658 const TargetLibraryInfo *TLI,
1659 const DominatorTree *DT) {
1660 return ::SimplifyXorInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1663 static Type *GetCompareTy(Value *Op) {
1664 return CmpInst::makeCmpResultType(Op->getType());
1667 /// ExtractEquivalentCondition - Rummage around inside V looking for something
1668 /// equivalent to the comparison "LHS Pred RHS". Return such a value if found,
1669 /// otherwise return null. Helper function for analyzing max/min idioms.
1670 static Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred,
1671 Value *LHS, Value *RHS) {
1672 SelectInst *SI = dyn_cast<SelectInst>(V);
1675 CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
1678 Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
1679 if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
1681 if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
1682 LHS == CmpRHS && RHS == CmpLHS)
1687 static Constant *computePointerICmp(const DataLayout &TD,
1688 CmpInst::Predicate Pred,
1689 Value *LHS, Value *RHS) {
1690 // We can only fold certain predicates on pointer comparisons.
1695 // Equality comaprisons are easy to fold.
1696 case CmpInst::ICMP_EQ:
1697 case CmpInst::ICMP_NE:
1700 // We can only handle unsigned relational comparisons because 'inbounds' on
1701 // a GEP only protects against unsigned wrapping.
1702 case CmpInst::ICMP_UGT:
1703 case CmpInst::ICMP_UGE:
1704 case CmpInst::ICMP_ULT:
1705 case CmpInst::ICMP_ULE:
1706 // However, we have to switch them to their signed variants to handle
1707 // negative indices from the base pointer.
1708 Pred = ICmpInst::getSignedPredicate(Pred);
1712 Constant *LHSOffset = stripAndComputeConstantOffsets(TD, LHS);
1715 Constant *RHSOffset = stripAndComputeConstantOffsets(TD, RHS);
1719 // If LHS and RHS are not related via constant offsets to the same base
1720 // value, there is nothing we can do here.
1724 return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset);
1727 /// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
1728 /// fold the result. If not, this returns null.
1729 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
1730 const Query &Q, unsigned MaxRecurse) {
1731 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
1732 assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
1734 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
1735 if (Constant *CRHS = dyn_cast<Constant>(RHS))
1736 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.TD, Q.TLI);
1738 // If we have a constant, make sure it is on the RHS.
1739 std::swap(LHS, RHS);
1740 Pred = CmpInst::getSwappedPredicate(Pred);
1743 Type *ITy = GetCompareTy(LHS); // The return type.
1744 Type *OpTy = LHS->getType(); // The operand type.
1746 // icmp X, X -> true/false
1747 // X icmp undef -> true/false. For example, icmp ugt %X, undef -> false
1748 // because X could be 0.
1749 if (LHS == RHS || isa<UndefValue>(RHS))
1750 return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
1752 // Special case logic when the operands have i1 type.
1753 if (OpTy->getScalarType()->isIntegerTy(1)) {
1756 case ICmpInst::ICMP_EQ:
1758 if (match(RHS, m_One()))
1761 case ICmpInst::ICMP_NE:
1763 if (match(RHS, m_Zero()))
1766 case ICmpInst::ICMP_UGT:
1768 if (match(RHS, m_Zero()))
1771 case ICmpInst::ICMP_UGE:
1773 if (match(RHS, m_One()))
1776 case ICmpInst::ICMP_SLT:
1778 if (match(RHS, m_Zero()))
1781 case ICmpInst::ICMP_SLE:
1783 if (match(RHS, m_One()))
1789 // icmp <object*>, <object*/null> - Different identified objects have
1790 // different addresses (unless null), and what's more the address of an
1791 // identified local is never equal to another argument (again, barring null).
1792 // Note that generalizing to the case where LHS is a global variable address
1793 // or null is pointless, since if both LHS and RHS are constants then we
1794 // already constant folded the compare, and if only one of them is then we
1795 // moved it to RHS already.
1796 Value *LHSPtr = LHS->stripPointerCasts();
1797 Value *RHSPtr = RHS->stripPointerCasts();
1798 if (LHSPtr == RHSPtr)
1799 return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
1801 // Be more aggressive about stripping pointer adjustments when checking a
1802 // comparison of an alloca address to another object. We can rip off all
1803 // inbounds GEP operations, even if they are variable.
1804 LHSPtr = LHSPtr->stripInBoundsOffsets();
1805 if (llvm::isIdentifiedObject(LHSPtr)) {
1806 RHSPtr = RHSPtr->stripInBoundsOffsets();
1807 if (llvm::isKnownNonNull(LHSPtr) || llvm::isKnownNonNull(RHSPtr)) {
1808 // If both sides are different identified objects, they aren't equal
1809 // unless they're null.
1810 if (LHSPtr != RHSPtr && llvm::isIdentifiedObject(RHSPtr) &&
1811 Pred == CmpInst::ICMP_EQ)
1812 return ConstantInt::get(ITy, false);
1814 // A local identified object (alloca or noalias call) can't equal any
1815 // incoming argument, unless they're both null or they belong to
1816 // different functions. The latter happens during inlining.
1817 if (Instruction *LHSInst = dyn_cast<Instruction>(LHSPtr))
1818 if (Argument *RHSArg = dyn_cast<Argument>(RHSPtr))
1819 if (LHSInst->getParent()->getParent() == RHSArg->getParent() &&
1820 Pred == CmpInst::ICMP_EQ)
1821 return ConstantInt::get(ITy, false);
1824 // Assume that the constant null is on the right.
1825 if (llvm::isKnownNonNull(LHSPtr) && isa<ConstantPointerNull>(RHSPtr)) {
1826 if (Pred == CmpInst::ICMP_EQ)
1827 return ConstantInt::get(ITy, false);
1828 else if (Pred == CmpInst::ICMP_NE)
1829 return ConstantInt::get(ITy, true);
1831 } else if (Argument *LHSArg = dyn_cast<Argument>(LHSPtr)) {
1832 RHSPtr = RHSPtr->stripInBoundsOffsets();
1833 // An alloca can't be equal to an argument unless they come from separate
1834 // functions via inlining.
1835 if (AllocaInst *RHSInst = dyn_cast<AllocaInst>(RHSPtr)) {
1836 if (LHSArg->getParent() == RHSInst->getParent()->getParent()) {
1837 if (Pred == CmpInst::ICMP_EQ)
1838 return ConstantInt::get(ITy, false);
1839 else if (Pred == CmpInst::ICMP_NE)
1840 return ConstantInt::get(ITy, true);
1845 // If we are comparing with zero then try hard since this is a common case.
1846 if (match(RHS, m_Zero())) {
1847 bool LHSKnownNonNegative, LHSKnownNegative;
1849 default: llvm_unreachable("Unknown ICmp predicate!");
1850 case ICmpInst::ICMP_ULT:
1851 return getFalse(ITy);
1852 case ICmpInst::ICMP_UGE:
1853 return getTrue(ITy);
1854 case ICmpInst::ICMP_EQ:
1855 case ICmpInst::ICMP_ULE:
1856 if (isKnownNonZero(LHS, Q.TD))
1857 return getFalse(ITy);
1859 case ICmpInst::ICMP_NE:
1860 case ICmpInst::ICMP_UGT:
1861 if (isKnownNonZero(LHS, Q.TD))
1862 return getTrue(ITy);
1864 case ICmpInst::ICMP_SLT:
1865 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1866 if (LHSKnownNegative)
1867 return getTrue(ITy);
1868 if (LHSKnownNonNegative)
1869 return getFalse(ITy);
1871 case ICmpInst::ICMP_SLE:
1872 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1873 if (LHSKnownNegative)
1874 return getTrue(ITy);
1875 if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.TD))
1876 return getFalse(ITy);
1878 case ICmpInst::ICMP_SGE:
1879 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1880 if (LHSKnownNegative)
1881 return getFalse(ITy);
1882 if (LHSKnownNonNegative)
1883 return getTrue(ITy);
1885 case ICmpInst::ICMP_SGT:
1886 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1887 if (LHSKnownNegative)
1888 return getFalse(ITy);
1889 if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.TD))
1890 return getTrue(ITy);
1895 // See if we are doing a comparison with a constant integer.
1896 if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
1897 // Rule out tautological comparisons (eg., ult 0 or uge 0).
1898 ConstantRange RHS_CR = ICmpInst::makeConstantRange(Pred, CI->getValue());
1899 if (RHS_CR.isEmptySet())
1900 return ConstantInt::getFalse(CI->getContext());
1901 if (RHS_CR.isFullSet())
1902 return ConstantInt::getTrue(CI->getContext());
1904 // Many binary operators with constant RHS have easy to compute constant
1905 // range. Use them to check whether the comparison is a tautology.
1906 uint32_t Width = CI->getBitWidth();
1907 APInt Lower = APInt(Width, 0);
1908 APInt Upper = APInt(Width, 0);
1910 if (match(LHS, m_URem(m_Value(), m_ConstantInt(CI2)))) {
1911 // 'urem x, CI2' produces [0, CI2).
1912 Upper = CI2->getValue();
1913 } else if (match(LHS, m_SRem(m_Value(), m_ConstantInt(CI2)))) {
1914 // 'srem x, CI2' produces (-|CI2|, |CI2|).
1915 Upper = CI2->getValue().abs();
1916 Lower = (-Upper) + 1;
1917 } else if (match(LHS, m_UDiv(m_ConstantInt(CI2), m_Value()))) {
1918 // 'udiv CI2, x' produces [0, CI2].
1919 Upper = CI2->getValue() + 1;
1920 } else if (match(LHS, m_UDiv(m_Value(), m_ConstantInt(CI2)))) {
1921 // 'udiv x, CI2' produces [0, UINT_MAX / CI2].
1922 APInt NegOne = APInt::getAllOnesValue(Width);
1924 Upper = NegOne.udiv(CI2->getValue()) + 1;
1925 } else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) {
1926 // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2].
1927 APInt IntMin = APInt::getSignedMinValue(Width);
1928 APInt IntMax = APInt::getSignedMaxValue(Width);
1929 APInt Val = CI2->getValue().abs();
1930 if (!Val.isMinValue()) {
1931 Lower = IntMin.sdiv(Val);
1932 Upper = IntMax.sdiv(Val) + 1;
1934 } else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) {
1935 // 'lshr x, CI2' produces [0, UINT_MAX >> CI2].
1936 APInt NegOne = APInt::getAllOnesValue(Width);
1937 if (CI2->getValue().ult(Width))
1938 Upper = NegOne.lshr(CI2->getValue()) + 1;
1939 } else if (match(LHS, m_AShr(m_Value(), m_ConstantInt(CI2)))) {
1940 // 'ashr x, CI2' produces [INT_MIN >> CI2, INT_MAX >> CI2].
1941 APInt IntMin = APInt::getSignedMinValue(Width);
1942 APInt IntMax = APInt::getSignedMaxValue(Width);
1943 if (CI2->getValue().ult(Width)) {
1944 Lower = IntMin.ashr(CI2->getValue());
1945 Upper = IntMax.ashr(CI2->getValue()) + 1;
1947 } else if (match(LHS, m_Or(m_Value(), m_ConstantInt(CI2)))) {
1948 // 'or x, CI2' produces [CI2, UINT_MAX].
1949 Lower = CI2->getValue();
1950 } else if (match(LHS, m_And(m_Value(), m_ConstantInt(CI2)))) {
1951 // 'and x, CI2' produces [0, CI2].
1952 Upper = CI2->getValue() + 1;
1954 if (Lower != Upper) {
1955 ConstantRange LHS_CR = ConstantRange(Lower, Upper);
1956 if (RHS_CR.contains(LHS_CR))
1957 return ConstantInt::getTrue(RHS->getContext());
1958 if (RHS_CR.inverse().contains(LHS_CR))
1959 return ConstantInt::getFalse(RHS->getContext());
1963 // Compare of cast, for example (zext X) != 0 -> X != 0
1964 if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
1965 Instruction *LI = cast<CastInst>(LHS);
1966 Value *SrcOp = LI->getOperand(0);
1967 Type *SrcTy = SrcOp->getType();
1968 Type *DstTy = LI->getType();
1970 // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
1971 // if the integer type is the same size as the pointer type.
1972 if (MaxRecurse && Q.TD && isa<PtrToIntInst>(LI) &&
1973 Q.TD->getPointerSizeInBits() == DstTy->getPrimitiveSizeInBits()) {
1974 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
1975 // Transfer the cast to the constant.
1976 if (Value *V = SimplifyICmpInst(Pred, SrcOp,
1977 ConstantExpr::getIntToPtr(RHSC, SrcTy),
1980 } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
1981 if (RI->getOperand(0)->getType() == SrcTy)
1982 // Compare without the cast.
1983 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
1989 if (isa<ZExtInst>(LHS)) {
1990 // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
1992 if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
1993 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
1994 // Compare X and Y. Note that signed predicates become unsigned.
1995 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
1996 SrcOp, RI->getOperand(0), Q,
2000 // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
2001 // too. If not, then try to deduce the result of the comparison.
2002 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2003 // Compute the constant that would happen if we truncated to SrcTy then
2004 // reextended to DstTy.
2005 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2006 Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
2008 // If the re-extended constant didn't change then this is effectively
2009 // also a case of comparing two zero-extended values.
2010 if (RExt == CI && MaxRecurse)
2011 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
2012 SrcOp, Trunc, Q, MaxRecurse-1))
2015 // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
2016 // there. Use this to work out the result of the comparison.
2019 default: llvm_unreachable("Unknown ICmp predicate!");
2021 case ICmpInst::ICMP_EQ:
2022 case ICmpInst::ICMP_UGT:
2023 case ICmpInst::ICMP_UGE:
2024 return ConstantInt::getFalse(CI->getContext());
2026 case ICmpInst::ICMP_NE:
2027 case ICmpInst::ICMP_ULT:
2028 case ICmpInst::ICMP_ULE:
2029 return ConstantInt::getTrue(CI->getContext());
2031 // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
2032 // is non-negative then LHS <s RHS.
2033 case ICmpInst::ICMP_SGT:
2034 case ICmpInst::ICMP_SGE:
2035 return CI->getValue().isNegative() ?
2036 ConstantInt::getTrue(CI->getContext()) :
2037 ConstantInt::getFalse(CI->getContext());
2039 case ICmpInst::ICMP_SLT:
2040 case ICmpInst::ICMP_SLE:
2041 return CI->getValue().isNegative() ?
2042 ConstantInt::getFalse(CI->getContext()) :
2043 ConstantInt::getTrue(CI->getContext());
2049 if (isa<SExtInst>(LHS)) {
2050 // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
2052 if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
2053 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2054 // Compare X and Y. Note that the predicate does not change.
2055 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2059 // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
2060 // too. If not, then try to deduce the result of the comparison.
2061 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2062 // Compute the constant that would happen if we truncated to SrcTy then
2063 // reextended to DstTy.
2064 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2065 Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
2067 // If the re-extended constant didn't change then this is effectively
2068 // also a case of comparing two sign-extended values.
2069 if (RExt == CI && MaxRecurse)
2070 if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
2073 // Otherwise the upper bits of LHS are all equal, while RHS has varying
2074 // bits there. Use this to work out the result of the comparison.
2077 default: llvm_unreachable("Unknown ICmp predicate!");
2078 case ICmpInst::ICMP_EQ:
2079 return ConstantInt::getFalse(CI->getContext());
2080 case ICmpInst::ICMP_NE:
2081 return ConstantInt::getTrue(CI->getContext());
2083 // If RHS is non-negative then LHS <s RHS. If RHS is negative then
2085 case ICmpInst::ICMP_SGT:
2086 case ICmpInst::ICMP_SGE:
2087 return CI->getValue().isNegative() ?
2088 ConstantInt::getTrue(CI->getContext()) :
2089 ConstantInt::getFalse(CI->getContext());
2090 case ICmpInst::ICMP_SLT:
2091 case ICmpInst::ICMP_SLE:
2092 return CI->getValue().isNegative() ?
2093 ConstantInt::getFalse(CI->getContext()) :
2094 ConstantInt::getTrue(CI->getContext());
2096 // If LHS is non-negative then LHS <u RHS. If LHS is negative then
2098 case ICmpInst::ICMP_UGT:
2099 case ICmpInst::ICMP_UGE:
2100 // Comparison is true iff the LHS <s 0.
2102 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
2103 Constant::getNullValue(SrcTy),
2107 case ICmpInst::ICMP_ULT:
2108 case ICmpInst::ICMP_ULE:
2109 // Comparison is true iff the LHS >=s 0.
2111 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
2112 Constant::getNullValue(SrcTy),
2122 // Special logic for binary operators.
2123 BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
2124 BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
2125 if (MaxRecurse && (LBO || RBO)) {
2126 // Analyze the case when either LHS or RHS is an add instruction.
2127 Value *A = 0, *B = 0, *C = 0, *D = 0;
2128 // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
2129 bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
2130 if (LBO && LBO->getOpcode() == Instruction::Add) {
2131 A = LBO->getOperand(0); B = LBO->getOperand(1);
2132 NoLHSWrapProblem = ICmpInst::isEquality(Pred) ||
2133 (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
2134 (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
2136 if (RBO && RBO->getOpcode() == Instruction::Add) {
2137 C = RBO->getOperand(0); D = RBO->getOperand(1);
2138 NoRHSWrapProblem = ICmpInst::isEquality(Pred) ||
2139 (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
2140 (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
2143 // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
2144 if ((A == RHS || B == RHS) && NoLHSWrapProblem)
2145 if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
2146 Constant::getNullValue(RHS->getType()),
2150 // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
2151 if ((C == LHS || D == LHS) && NoRHSWrapProblem)
2152 if (Value *V = SimplifyICmpInst(Pred,
2153 Constant::getNullValue(LHS->getType()),
2154 C == LHS ? D : C, Q, MaxRecurse-1))
2157 // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
2158 if (A && C && (A == C || A == D || B == C || B == D) &&
2159 NoLHSWrapProblem && NoRHSWrapProblem) {
2160 // Determine Y and Z in the form icmp (X+Y), (X+Z).
2163 // C + B == C + D -> B == D
2166 } else if (A == D) {
2167 // D + B == C + D -> B == C
2170 } else if (B == C) {
2171 // A + C == C + D -> A == D
2176 // A + D == C + D -> A == C
2180 if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse-1))
2185 if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
2186 bool KnownNonNegative, KnownNegative;
2190 case ICmpInst::ICMP_SGT:
2191 case ICmpInst::ICMP_SGE:
2192 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.TD);
2193 if (!KnownNonNegative)
2196 case ICmpInst::ICMP_EQ:
2197 case ICmpInst::ICMP_UGT:
2198 case ICmpInst::ICMP_UGE:
2199 return getFalse(ITy);
2200 case ICmpInst::ICMP_SLT:
2201 case ICmpInst::ICMP_SLE:
2202 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.TD);
2203 if (!KnownNonNegative)
2206 case ICmpInst::ICMP_NE:
2207 case ICmpInst::ICMP_ULT:
2208 case ICmpInst::ICMP_ULE:
2209 return getTrue(ITy);
2212 if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
2213 bool KnownNonNegative, KnownNegative;
2217 case ICmpInst::ICMP_SGT:
2218 case ICmpInst::ICMP_SGE:
2219 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.TD);
2220 if (!KnownNonNegative)
2223 case ICmpInst::ICMP_NE:
2224 case ICmpInst::ICMP_UGT:
2225 case ICmpInst::ICMP_UGE:
2226 return getTrue(ITy);
2227 case ICmpInst::ICMP_SLT:
2228 case ICmpInst::ICMP_SLE:
2229 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.TD);
2230 if (!KnownNonNegative)
2233 case ICmpInst::ICMP_EQ:
2234 case ICmpInst::ICMP_ULT:
2235 case ICmpInst::ICMP_ULE:
2236 return getFalse(ITy);
2241 if (LBO && match(LBO, m_UDiv(m_Specific(RHS), m_Value()))) {
2242 // icmp pred (X /u Y), X
2243 if (Pred == ICmpInst::ICMP_UGT)
2244 return getFalse(ITy);
2245 if (Pred == ICmpInst::ICMP_ULE)
2246 return getTrue(ITy);
2249 if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
2250 LBO->getOperand(1) == RBO->getOperand(1)) {
2251 switch (LBO->getOpcode()) {
2253 case Instruction::UDiv:
2254 case Instruction::LShr:
2255 if (ICmpInst::isSigned(Pred))
2258 case Instruction::SDiv:
2259 case Instruction::AShr:
2260 if (!LBO->isExact() || !RBO->isExact())
2262 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2263 RBO->getOperand(0), Q, MaxRecurse-1))
2266 case Instruction::Shl: {
2267 bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
2268 bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
2271 if (!NSW && ICmpInst::isSigned(Pred))
2273 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2274 RBO->getOperand(0), Q, MaxRecurse-1))
2281 // Simplify comparisons involving max/min.
2283 CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE;
2284 CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
2286 // Signed variants on "max(a,b)>=a -> true".
2287 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2288 if (A != RHS) std::swap(A, B); // smax(A, B) pred A.
2289 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2290 // We analyze this as smax(A, B) pred A.
2292 } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
2293 (A == LHS || B == LHS)) {
2294 if (A != LHS) std::swap(A, B); // A pred smax(A, B).
2295 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2296 // We analyze this as smax(A, B) swapped-pred A.
2297 P = CmpInst::getSwappedPredicate(Pred);
2298 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2299 (A == RHS || B == RHS)) {
2300 if (A != RHS) std::swap(A, B); // smin(A, B) pred A.
2301 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2302 // We analyze this as smax(-A, -B) swapped-pred -A.
2303 // Note that we do not need to actually form -A or -B thanks to EqP.
2304 P = CmpInst::getSwappedPredicate(Pred);
2305 } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
2306 (A == LHS || B == LHS)) {
2307 if (A != LHS) std::swap(A, B); // A pred smin(A, B).
2308 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2309 // We analyze this as smax(-A, -B) pred -A.
2310 // Note that we do not need to actually form -A or -B thanks to EqP.
2313 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2314 // Cases correspond to "max(A, B) p A".
2318 case CmpInst::ICMP_EQ:
2319 case CmpInst::ICMP_SLE:
2320 // Equivalent to "A EqP B". This may be the same as the condition tested
2321 // in the max/min; if so, we can just return that.
2322 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2324 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2326 // Otherwise, see if "A EqP B" simplifies.
2328 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2331 case CmpInst::ICMP_NE:
2332 case CmpInst::ICMP_SGT: {
2333 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2334 // Equivalent to "A InvEqP B". This may be the same as the condition
2335 // tested in the max/min; if so, we can just return that.
2336 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2338 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2340 // Otherwise, see if "A InvEqP B" simplifies.
2342 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2346 case CmpInst::ICMP_SGE:
2348 return getTrue(ITy);
2349 case CmpInst::ICMP_SLT:
2351 return getFalse(ITy);
2355 // Unsigned variants on "max(a,b)>=a -> true".
2356 P = CmpInst::BAD_ICMP_PREDICATE;
2357 if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2358 if (A != RHS) std::swap(A, B); // umax(A, B) pred A.
2359 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2360 // We analyze this as umax(A, B) pred A.
2362 } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
2363 (A == LHS || B == LHS)) {
2364 if (A != LHS) std::swap(A, B); // A pred umax(A, B).
2365 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2366 // We analyze this as umax(A, B) swapped-pred A.
2367 P = CmpInst::getSwappedPredicate(Pred);
2368 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2369 (A == RHS || B == RHS)) {
2370 if (A != RHS) std::swap(A, B); // umin(A, B) pred A.
2371 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2372 // We analyze this as umax(-A, -B) swapped-pred -A.
2373 // Note that we do not need to actually form -A or -B thanks to EqP.
2374 P = CmpInst::getSwappedPredicate(Pred);
2375 } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
2376 (A == LHS || B == LHS)) {
2377 if (A != LHS) std::swap(A, B); // A pred umin(A, B).
2378 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2379 // We analyze this as umax(-A, -B) pred -A.
2380 // Note that we do not need to actually form -A or -B thanks to EqP.
2383 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2384 // Cases correspond to "max(A, B) p A".
2388 case CmpInst::ICMP_EQ:
2389 case CmpInst::ICMP_ULE:
2390 // Equivalent to "A EqP B". This may be the same as the condition tested
2391 // in the max/min; if so, we can just return that.
2392 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2394 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2396 // Otherwise, see if "A EqP B" simplifies.
2398 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2401 case CmpInst::ICMP_NE:
2402 case CmpInst::ICMP_UGT: {
2403 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2404 // Equivalent to "A InvEqP B". This may be the same as the condition
2405 // tested in the max/min; if so, we can just return that.
2406 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2408 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2410 // Otherwise, see if "A InvEqP B" simplifies.
2412 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2416 case CmpInst::ICMP_UGE:
2418 return getTrue(ITy);
2419 case CmpInst::ICMP_ULT:
2421 return getFalse(ITy);
2425 // Variants on "max(x,y) >= min(x,z)".
2427 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
2428 match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
2429 (A == C || A == D || B == C || B == D)) {
2430 // max(x, ?) pred min(x, ?).
2431 if (Pred == CmpInst::ICMP_SGE)
2433 return getTrue(ITy);
2434 if (Pred == CmpInst::ICMP_SLT)
2436 return getFalse(ITy);
2437 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2438 match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
2439 (A == C || A == D || B == C || B == D)) {
2440 // min(x, ?) pred max(x, ?).
2441 if (Pred == CmpInst::ICMP_SLE)
2443 return getTrue(ITy);
2444 if (Pred == CmpInst::ICMP_SGT)
2446 return getFalse(ITy);
2447 } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
2448 match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
2449 (A == C || A == D || B == C || B == D)) {
2450 // max(x, ?) pred min(x, ?).
2451 if (Pred == CmpInst::ICMP_UGE)
2453 return getTrue(ITy);
2454 if (Pred == CmpInst::ICMP_ULT)
2456 return getFalse(ITy);
2457 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2458 match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
2459 (A == C || A == D || B == C || B == D)) {
2460 // min(x, ?) pred max(x, ?).
2461 if (Pred == CmpInst::ICMP_ULE)
2463 return getTrue(ITy);
2464 if (Pred == CmpInst::ICMP_UGT)
2466 return getFalse(ITy);
2469 // Simplify comparisons of related pointers using a powerful, recursive
2470 // GEP-walk when we have target data available..
2471 if (Q.TD && LHS->getType()->isPointerTy() && RHS->getType()->isPointerTy())
2472 if (Constant *C = computePointerICmp(*Q.TD, Pred, LHS, RHS))
2475 if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
2476 if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
2477 if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
2478 GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
2479 (ICmpInst::isEquality(Pred) ||
2480 (GLHS->isInBounds() && GRHS->isInBounds() &&
2481 Pred == ICmpInst::getSignedPredicate(Pred)))) {
2482 // The bases are equal and the indices are constant. Build a constant
2483 // expression GEP with the same indices and a null base pointer to see
2484 // what constant folding can make out of it.
2485 Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
2486 SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
2487 Constant *NewLHS = ConstantExpr::getGetElementPtr(Null, IndicesLHS);
2489 SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
2490 Constant *NewRHS = ConstantExpr::getGetElementPtr(Null, IndicesRHS);
2491 return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
2496 // If the comparison is with the result of a select instruction, check whether
2497 // comparing with either branch of the select always yields the same value.
2498 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2499 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
2502 // If the comparison is with the result of a phi instruction, check whether
2503 // doing the compare with each incoming phi value yields a common result.
2504 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2505 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
2511 Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2512 const DataLayout *TD,
2513 const TargetLibraryInfo *TLI,
2514 const DominatorTree *DT) {
2515 return ::SimplifyICmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
2519 /// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can
2520 /// fold the result. If not, this returns null.
2521 static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2522 const Query &Q, unsigned MaxRecurse) {
2523 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
2524 assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
2526 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
2527 if (Constant *CRHS = dyn_cast<Constant>(RHS))
2528 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.TD, Q.TLI);
2530 // If we have a constant, make sure it is on the RHS.
2531 std::swap(LHS, RHS);
2532 Pred = CmpInst::getSwappedPredicate(Pred);
2535 // Fold trivial predicates.
2536 if (Pred == FCmpInst::FCMP_FALSE)
2537 return ConstantInt::get(GetCompareTy(LHS), 0);
2538 if (Pred == FCmpInst::FCMP_TRUE)
2539 return ConstantInt::get(GetCompareTy(LHS), 1);
2541 if (isa<UndefValue>(RHS)) // fcmp pred X, undef -> undef
2542 return UndefValue::get(GetCompareTy(LHS));
2544 // fcmp x,x -> true/false. Not all compares are foldable.
2546 if (CmpInst::isTrueWhenEqual(Pred))
2547 return ConstantInt::get(GetCompareTy(LHS), 1);
2548 if (CmpInst::isFalseWhenEqual(Pred))
2549 return ConstantInt::get(GetCompareTy(LHS), 0);
2552 // Handle fcmp with constant RHS
2553 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
2554 // If the constant is a nan, see if we can fold the comparison based on it.
2555 if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHSC)) {
2556 if (CFP->getValueAPF().isNaN()) {
2557 if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo"
2558 return ConstantInt::getFalse(CFP->getContext());
2559 assert(FCmpInst::isUnordered(Pred) &&
2560 "Comparison must be either ordered or unordered!");
2561 // True if unordered.
2562 return ConstantInt::getTrue(CFP->getContext());
2564 // Check whether the constant is an infinity.
2565 if (CFP->getValueAPF().isInfinity()) {
2566 if (CFP->getValueAPF().isNegative()) {
2568 case FCmpInst::FCMP_OLT:
2569 // No value is ordered and less than negative infinity.
2570 return ConstantInt::getFalse(CFP->getContext());
2571 case FCmpInst::FCMP_UGE:
2572 // All values are unordered with or at least negative infinity.
2573 return ConstantInt::getTrue(CFP->getContext());
2579 case FCmpInst::FCMP_OGT:
2580 // No value is ordered and greater than infinity.
2581 return ConstantInt::getFalse(CFP->getContext());
2582 case FCmpInst::FCMP_ULE:
2583 // All values are unordered with and at most infinity.
2584 return ConstantInt::getTrue(CFP->getContext());
2593 // If the comparison is with the result of a select instruction, check whether
2594 // comparing with either branch of the select always yields the same value.
2595 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2596 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
2599 // If the comparison is with the result of a phi instruction, check whether
2600 // doing the compare with each incoming phi value yields a common result.
2601 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2602 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
2608 Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2609 const DataLayout *TD,
2610 const TargetLibraryInfo *TLI,
2611 const DominatorTree *DT) {
2612 return ::SimplifyFCmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
2616 /// SimplifySelectInst - Given operands for a SelectInst, see if we can fold
2617 /// the result. If not, this returns null.
2618 static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal,
2619 Value *FalseVal, const Query &Q,
2620 unsigned MaxRecurse) {
2621 // select true, X, Y -> X
2622 // select false, X, Y -> Y
2623 if (ConstantInt *CB = dyn_cast<ConstantInt>(CondVal))
2624 return CB->getZExtValue() ? TrueVal : FalseVal;
2626 // select C, X, X -> X
2627 if (TrueVal == FalseVal)
2630 if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y
2631 if (isa<Constant>(TrueVal))
2635 if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X
2637 if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
2643 Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
2644 const DataLayout *TD,
2645 const TargetLibraryInfo *TLI,
2646 const DominatorTree *DT) {
2647 return ::SimplifySelectInst(Cond, TrueVal, FalseVal, Query (TD, TLI, DT),
2651 /// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
2652 /// fold the result. If not, this returns null.
2653 static Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const Query &Q, unsigned) {
2654 // The type of the GEP pointer operand.
2655 PointerType *PtrTy = dyn_cast<PointerType>(Ops[0]->getType());
2656 // The GEP pointer operand is not a pointer, it's a vector of pointers.
2660 // getelementptr P -> P.
2661 if (Ops.size() == 1)
2664 if (isa<UndefValue>(Ops[0])) {
2665 // Compute the (pointer) type returned by the GEP instruction.
2666 Type *LastType = GetElementPtrInst::getIndexedType(PtrTy, Ops.slice(1));
2667 Type *GEPTy = PointerType::get(LastType, PtrTy->getAddressSpace());
2668 return UndefValue::get(GEPTy);
2671 if (Ops.size() == 2) {
2672 // getelementptr P, 0 -> P.
2673 if (ConstantInt *C = dyn_cast<ConstantInt>(Ops[1]))
2676 // getelementptr P, N -> P if P points to a type of zero size.
2678 Type *Ty = PtrTy->getElementType();
2679 if (Ty->isSized() && Q.TD->getTypeAllocSize(Ty) == 0)
2684 // Check to see if this is constant foldable.
2685 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
2686 if (!isa<Constant>(Ops[i]))
2689 return ConstantExpr::getGetElementPtr(cast<Constant>(Ops[0]), Ops.slice(1));
2692 Value *llvm::SimplifyGEPInst(ArrayRef<Value *> Ops, const DataLayout *TD,
2693 const TargetLibraryInfo *TLI,
2694 const DominatorTree *DT) {
2695 return ::SimplifyGEPInst(Ops, Query (TD, TLI, DT), RecursionLimit);
2698 /// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we
2699 /// can fold the result. If not, this returns null.
2700 static Value *SimplifyInsertValueInst(Value *Agg, Value *Val,
2701 ArrayRef<unsigned> Idxs, const Query &Q,
2703 if (Constant *CAgg = dyn_cast<Constant>(Agg))
2704 if (Constant *CVal = dyn_cast<Constant>(Val))
2705 return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
2707 // insertvalue x, undef, n -> x
2708 if (match(Val, m_Undef()))
2711 // insertvalue x, (extractvalue y, n), n
2712 if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
2713 if (EV->getAggregateOperand()->getType() == Agg->getType() &&
2714 EV->getIndices() == Idxs) {
2715 // insertvalue undef, (extractvalue y, n), n -> y
2716 if (match(Agg, m_Undef()))
2717 return EV->getAggregateOperand();
2719 // insertvalue y, (extractvalue y, n), n -> y
2720 if (Agg == EV->getAggregateOperand())
2727 Value *llvm::SimplifyInsertValueInst(Value *Agg, Value *Val,
2728 ArrayRef<unsigned> Idxs,
2729 const DataLayout *TD,
2730 const TargetLibraryInfo *TLI,
2731 const DominatorTree *DT) {
2732 return ::SimplifyInsertValueInst(Agg, Val, Idxs, Query (TD, TLI, DT),
2736 /// SimplifyPHINode - See if we can fold the given phi. If not, returns null.
2737 static Value *SimplifyPHINode(PHINode *PN, const Query &Q) {
2738 // If all of the PHI's incoming values are the same then replace the PHI node
2739 // with the common value.
2740 Value *CommonValue = 0;
2741 bool HasUndefInput = false;
2742 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
2743 Value *Incoming = PN->getIncomingValue(i);
2744 // If the incoming value is the phi node itself, it can safely be skipped.
2745 if (Incoming == PN) continue;
2746 if (isa<UndefValue>(Incoming)) {
2747 // Remember that we saw an undef value, but otherwise ignore them.
2748 HasUndefInput = true;
2751 if (CommonValue && Incoming != CommonValue)
2752 return 0; // Not the same, bail out.
2753 CommonValue = Incoming;
2756 // If CommonValue is null then all of the incoming values were either undef or
2757 // equal to the phi node itself.
2759 return UndefValue::get(PN->getType());
2761 // If we have a PHI node like phi(X, undef, X), where X is defined by some
2762 // instruction, we cannot return X as the result of the PHI node unless it
2763 // dominates the PHI block.
2765 return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : 0;
2770 static Value *SimplifyTruncInst(Value *Op, Type *Ty, const Query &Q, unsigned) {
2771 if (Constant *C = dyn_cast<Constant>(Op))
2772 return ConstantFoldInstOperands(Instruction::Trunc, Ty, C, Q.TD, Q.TLI);
2777 Value *llvm::SimplifyTruncInst(Value *Op, Type *Ty, const DataLayout *TD,
2778 const TargetLibraryInfo *TLI,
2779 const DominatorTree *DT) {
2780 return ::SimplifyTruncInst(Op, Ty, Query (TD, TLI, DT), RecursionLimit);
2783 //=== Helper functions for higher up the class hierarchy.
2785 /// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
2786 /// fold the result. If not, this returns null.
2787 static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
2788 const Query &Q, unsigned MaxRecurse) {
2790 case Instruction::Add:
2791 return SimplifyAddInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2793 case Instruction::FAdd:
2794 return SimplifyFAddInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
2796 case Instruction::Sub:
2797 return SimplifySubInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2799 case Instruction::FSub:
2800 return SimplifyFSubInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
2802 case Instruction::Mul: return SimplifyMulInst (LHS, RHS, Q, MaxRecurse);
2803 case Instruction::FMul:
2804 return SimplifyFMulInst (LHS, RHS, FastMathFlags(), Q, MaxRecurse);
2805 case Instruction::SDiv: return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
2806 case Instruction::UDiv: return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
2807 case Instruction::FDiv: return SimplifyFDivInst(LHS, RHS, Q, MaxRecurse);
2808 case Instruction::SRem: return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
2809 case Instruction::URem: return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
2810 case Instruction::FRem: return SimplifyFRemInst(LHS, RHS, Q, MaxRecurse);
2811 case Instruction::Shl:
2812 return SimplifyShlInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2814 case Instruction::LShr:
2815 return SimplifyLShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
2816 case Instruction::AShr:
2817 return SimplifyAShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
2818 case Instruction::And: return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
2819 case Instruction::Or: return SimplifyOrInst (LHS, RHS, Q, MaxRecurse);
2820 case Instruction::Xor: return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
2822 if (Constant *CLHS = dyn_cast<Constant>(LHS))
2823 if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
2824 Constant *COps[] = {CLHS, CRHS};
2825 return ConstantFoldInstOperands(Opcode, LHS->getType(), COps, Q.TD,
2829 // If the operation is associative, try some generic simplifications.
2830 if (Instruction::isAssociative(Opcode))
2831 if (Value *V = SimplifyAssociativeBinOp(Opcode, LHS, RHS, Q, MaxRecurse))
2834 // If the operation is with the result of a select instruction check whether
2835 // operating on either branch of the select always yields the same value.
2836 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2837 if (Value *V = ThreadBinOpOverSelect(Opcode, LHS, RHS, Q, MaxRecurse))
2840 // If the operation is with the result of a phi instruction, check whether
2841 // operating on all incoming values of the phi always yields the same value.
2842 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2843 if (Value *V = ThreadBinOpOverPHI(Opcode, LHS, RHS, Q, MaxRecurse))
2850 Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
2851 const DataLayout *TD, const TargetLibraryInfo *TLI,
2852 const DominatorTree *DT) {
2853 return ::SimplifyBinOp(Opcode, LHS, RHS, Query (TD, TLI, DT), RecursionLimit);
2856 /// SimplifyCmpInst - Given operands for a CmpInst, see if we can
2857 /// fold the result.
2858 static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2859 const Query &Q, unsigned MaxRecurse) {
2860 if (CmpInst::isIntPredicate((CmpInst::Predicate)Predicate))
2861 return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
2862 return SimplifyFCmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
2865 Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2866 const DataLayout *TD, const TargetLibraryInfo *TLI,
2867 const DominatorTree *DT) {
2868 return ::SimplifyCmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
2872 template <typename IterTy>
2873 static Value *SimplifyCall(Value *V, IterTy ArgBegin, IterTy ArgEnd,
2874 const Query &Q, unsigned MaxRecurse) {
2875 Type *Ty = V->getType();
2876 if (PointerType *PTy = dyn_cast<PointerType>(Ty))
2877 Ty = PTy->getElementType();
2878 FunctionType *FTy = cast<FunctionType>(Ty);
2880 // call undef -> undef
2881 if (isa<UndefValue>(V))
2882 return UndefValue::get(FTy->getReturnType());
2884 Function *F = dyn_cast<Function>(V);
2888 if (!canConstantFoldCallTo(F))
2891 SmallVector<Constant *, 4> ConstantArgs;
2892 ConstantArgs.reserve(ArgEnd - ArgBegin);
2893 for (IterTy I = ArgBegin, E = ArgEnd; I != E; ++I) {
2894 Constant *C = dyn_cast<Constant>(*I);
2897 ConstantArgs.push_back(C);
2900 return ConstantFoldCall(F, ConstantArgs, Q.TLI);
2903 Value *llvm::SimplifyCall(Value *V, User::op_iterator ArgBegin,
2904 User::op_iterator ArgEnd, const DataLayout *TD,
2905 const TargetLibraryInfo *TLI,
2906 const DominatorTree *DT) {
2907 return ::SimplifyCall(V, ArgBegin, ArgEnd, Query(TD, TLI, DT),
2911 Value *llvm::SimplifyCall(Value *V, ArrayRef<Value *> Args,
2912 const DataLayout *TD, const TargetLibraryInfo *TLI,
2913 const DominatorTree *DT) {
2914 return ::SimplifyCall(V, Args.begin(), Args.end(), Query(TD, TLI, DT),
2918 /// SimplifyInstruction - See if we can compute a simplified version of this
2919 /// instruction. If not, this returns null.
2920 Value *llvm::SimplifyInstruction(Instruction *I, const DataLayout *TD,
2921 const TargetLibraryInfo *TLI,
2922 const DominatorTree *DT) {
2925 switch (I->getOpcode()) {
2927 Result = ConstantFoldInstruction(I, TD, TLI);
2929 case Instruction::FAdd:
2930 Result = SimplifyFAddInst(I->getOperand(0), I->getOperand(1),
2931 I->getFastMathFlags(), TD, TLI, DT);
2933 case Instruction::Add:
2934 Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
2935 cast<BinaryOperator>(I)->hasNoSignedWrap(),
2936 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
2939 case Instruction::FSub:
2940 Result = SimplifyFSubInst(I->getOperand(0), I->getOperand(1),
2941 I->getFastMathFlags(), TD, TLI, DT);
2943 case Instruction::Sub:
2944 Result = SimplifySubInst(I->getOperand(0), I->getOperand(1),
2945 cast<BinaryOperator>(I)->hasNoSignedWrap(),
2946 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
2949 case Instruction::FMul:
2950 Result = SimplifyFMulInst(I->getOperand(0), I->getOperand(1),
2951 I->getFastMathFlags(), TD, TLI, DT);
2953 case Instruction::Mul:
2954 Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2956 case Instruction::SDiv:
2957 Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2959 case Instruction::UDiv:
2960 Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2962 case Instruction::FDiv:
2963 Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2965 case Instruction::SRem:
2966 Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2968 case Instruction::URem:
2969 Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2971 case Instruction::FRem:
2972 Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2974 case Instruction::Shl:
2975 Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1),
2976 cast<BinaryOperator>(I)->hasNoSignedWrap(),
2977 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
2980 case Instruction::LShr:
2981 Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
2982 cast<BinaryOperator>(I)->isExact(),
2985 case Instruction::AShr:
2986 Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
2987 cast<BinaryOperator>(I)->isExact(),
2990 case Instruction::And:
2991 Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2993 case Instruction::Or:
2994 Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2996 case Instruction::Xor:
2997 Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2999 case Instruction::ICmp:
3000 Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
3001 I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3003 case Instruction::FCmp:
3004 Result = SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(),
3005 I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3007 case Instruction::Select:
3008 Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
3009 I->getOperand(2), TD, TLI, DT);
3011 case Instruction::GetElementPtr: {
3012 SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end());
3013 Result = SimplifyGEPInst(Ops, TD, TLI, DT);
3016 case Instruction::InsertValue: {
3017 InsertValueInst *IV = cast<InsertValueInst>(I);
3018 Result = SimplifyInsertValueInst(IV->getAggregateOperand(),
3019 IV->getInsertedValueOperand(),
3020 IV->getIndices(), TD, TLI, DT);
3023 case Instruction::PHI:
3024 Result = SimplifyPHINode(cast<PHINode>(I), Query (TD, TLI, DT));
3026 case Instruction::Call: {
3027 CallSite CS(cast<CallInst>(I));
3028 Result = SimplifyCall(CS.getCalledValue(), CS.arg_begin(), CS.arg_end(),
3032 case Instruction::Trunc:
3033 Result = SimplifyTruncInst(I->getOperand(0), I->getType(), TD, TLI, DT);
3037 /// If called on unreachable code, the above logic may report that the
3038 /// instruction simplified to itself. Make life easier for users by
3039 /// detecting that case here, returning a safe value instead.
3040 return Result == I ? UndefValue::get(I->getType()) : Result;
3043 /// \brief Implementation of recursive simplification through an instructions
3046 /// This is the common implementation of the recursive simplification routines.
3047 /// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
3048 /// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
3049 /// instructions to process and attempt to simplify it using
3050 /// InstructionSimplify.
3052 /// This routine returns 'true' only when *it* simplifies something. The passed
3053 /// in simplified value does not count toward this.
3054 static bool replaceAndRecursivelySimplifyImpl(Instruction *I, Value *SimpleV,
3055 const DataLayout *TD,
3056 const TargetLibraryInfo *TLI,
3057 const DominatorTree *DT) {
3058 bool Simplified = false;
3059 SmallSetVector<Instruction *, 8> Worklist;
3061 // If we have an explicit value to collapse to, do that round of the
3062 // simplification loop by hand initially.
3064 for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE;
3067 Worklist.insert(cast<Instruction>(*UI));
3069 // Replace the instruction with its simplified value.
3070 I->replaceAllUsesWith(SimpleV);
3072 // Gracefully handle edge cases where the instruction is not wired into any
3075 I->eraseFromParent();
3080 // Note that we must test the size on each iteration, the worklist can grow.
3081 for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
3084 // See if this instruction simplifies.
3085 SimpleV = SimplifyInstruction(I, TD, TLI, DT);
3091 // Stash away all the uses of the old instruction so we can check them for
3092 // recursive simplifications after a RAUW. This is cheaper than checking all
3093 // uses of To on the recursive step in most cases.
3094 for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE;
3096 Worklist.insert(cast<Instruction>(*UI));
3098 // Replace the instruction with its simplified value.
3099 I->replaceAllUsesWith(SimpleV);
3101 // Gracefully handle edge cases where the instruction is not wired into any
3104 I->eraseFromParent();
3109 bool llvm::recursivelySimplifyInstruction(Instruction *I,
3110 const DataLayout *TD,
3111 const TargetLibraryInfo *TLI,
3112 const DominatorTree *DT) {
3113 return replaceAndRecursivelySimplifyImpl(I, 0, TD, TLI, DT);
3116 bool llvm::replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV,
3117 const DataLayout *TD,
3118 const TargetLibraryInfo *TLI,
3119 const DominatorTree *DT) {
3120 assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!");
3121 assert(SimpleV && "Must provide a simplified value.");
3122 return replaceAndRecursivelySimplifyImpl(I, SimpleV, TD, TLI, DT);