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 #include "llvm/Analysis/InstructionSimplify.h"
21 #include "llvm/ADT/SetVector.h"
22 #include "llvm/ADT/Statistic.h"
23 #include "llvm/Analysis/AliasAnalysis.h"
24 #include "llvm/Analysis/ConstantFolding.h"
25 #include "llvm/Analysis/MemoryBuiltins.h"
26 #include "llvm/Analysis/ValueTracking.h"
27 #include "llvm/IR/ConstantRange.h"
28 #include "llvm/IR/DataLayout.h"
29 #include "llvm/IR/Dominators.h"
30 #include "llvm/IR/GetElementPtrTypeIterator.h"
31 #include "llvm/IR/GlobalAlias.h"
32 #include "llvm/IR/Operator.h"
33 #include "llvm/IR/PatternMatch.h"
34 #include "llvm/IR/ValueHandle.h"
37 using namespace llvm::PatternMatch;
39 #define DEBUG_TYPE "instsimplify"
41 enum { RecursionLimit = 3 };
43 STATISTIC(NumExpand, "Number of expansions");
44 STATISTIC(NumReassoc, "Number of reassociations");
49 const TargetLibraryInfo *TLI;
50 const DominatorTree *DT;
52 const Instruction *CxtI;
54 Query(const DataLayout *DL, const TargetLibraryInfo *tli,
55 const DominatorTree *dt, AssumptionCache *ac = nullptr,
56 const Instruction *cxti = nullptr)
57 : DL(DL), TLI(tli), DT(dt), AC(ac), CxtI(cxti) {}
59 } // end anonymous namespace
61 static Value *SimplifyAndInst(Value *, Value *, const Query &, unsigned);
62 static Value *SimplifyBinOp(unsigned, Value *, Value *, const Query &,
64 static Value *SimplifyFPBinOp(unsigned, Value *, Value *, const FastMathFlags &,
65 const Query &, unsigned);
66 static Value *SimplifyCmpInst(unsigned, Value *, Value *, const Query &,
68 static Value *SimplifyOrInst(Value *, Value *, const Query &, unsigned);
69 static Value *SimplifyXorInst(Value *, Value *, const Query &, unsigned);
70 static Value *SimplifyTruncInst(Value *, Type *, const Query &, unsigned);
72 /// getFalse - For a boolean type, or a vector of boolean type, return false, or
73 /// a vector with every element false, as appropriate for the type.
74 static Constant *getFalse(Type *Ty) {
75 assert(Ty->getScalarType()->isIntegerTy(1) &&
76 "Expected i1 type or a vector of i1!");
77 return Constant::getNullValue(Ty);
80 /// getTrue - For a boolean type, or a vector of boolean type, return true, or
81 /// a vector with every element true, as appropriate for the type.
82 static Constant *getTrue(Type *Ty) {
83 assert(Ty->getScalarType()->isIntegerTy(1) &&
84 "Expected i1 type or a vector of i1!");
85 return Constant::getAllOnesValue(Ty);
88 /// isSameCompare - Is V equivalent to the comparison "LHS Pred RHS"?
89 static bool isSameCompare(Value *V, CmpInst::Predicate Pred, Value *LHS,
91 CmpInst *Cmp = dyn_cast<CmpInst>(V);
94 CmpInst::Predicate CPred = Cmp->getPredicate();
95 Value *CLHS = Cmp->getOperand(0), *CRHS = Cmp->getOperand(1);
96 if (CPred == Pred && CLHS == LHS && CRHS == RHS)
98 return CPred == CmpInst::getSwappedPredicate(Pred) && CLHS == RHS &&
102 /// ValueDominatesPHI - Does the given value dominate the specified phi node?
103 static bool ValueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
104 Instruction *I = dyn_cast<Instruction>(V);
106 // Arguments and constants dominate all instructions.
109 // If we are processing instructions (and/or basic blocks) that have not been
110 // fully added to a function, the parent nodes may still be null. Simply
111 // return the conservative answer in these cases.
112 if (!I->getParent() || !P->getParent() || !I->getParent()->getParent())
115 // If we have a DominatorTree then do a precise test.
117 if (!DT->isReachableFromEntry(P->getParent()))
119 if (!DT->isReachableFromEntry(I->getParent()))
121 return DT->dominates(I, P);
124 // Otherwise, if the instruction is in the entry block, and is not an invoke,
125 // then it obviously dominates all phi nodes.
126 if (I->getParent() == &I->getParent()->getParent()->getEntryBlock() &&
133 /// ExpandBinOp - Simplify "A op (B op' C)" by distributing op over op', turning
134 /// it into "(A op B) op' (A op C)". Here "op" is given by Opcode and "op'" is
135 /// given by OpcodeToExpand, while "A" corresponds to LHS and "B op' C" to RHS.
136 /// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)".
137 /// Returns the simplified value, or null if no simplification was performed.
138 static Value *ExpandBinOp(unsigned Opcode, Value *LHS, Value *RHS,
139 unsigned OpcToExpand, const Query &Q,
140 unsigned MaxRecurse) {
141 Instruction::BinaryOps OpcodeToExpand = (Instruction::BinaryOps)OpcToExpand;
142 // Recursion is always used, so bail out at once if we already hit the limit.
146 // Check whether the expression has the form "(A op' B) op C".
147 if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS))
148 if (Op0->getOpcode() == OpcodeToExpand) {
149 // It does! Try turning it into "(A op C) op' (B op C)".
150 Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS;
151 // Do "A op C" and "B op C" both simplify?
152 if (Value *L = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse))
153 if (Value *R = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
154 // They do! Return "L op' R" if it simplifies or is already available.
155 // If "L op' R" equals "A op' B" then "L op' R" is just the LHS.
156 if ((L == A && R == B) || (Instruction::isCommutative(OpcodeToExpand)
157 && L == B && R == A)) {
161 // Otherwise return "L op' R" if it simplifies.
162 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
169 // Check whether the expression has the form "A op (B op' C)".
170 if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS))
171 if (Op1->getOpcode() == OpcodeToExpand) {
172 // It does! Try turning it into "(A op B) op' (A op C)".
173 Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1);
174 // Do "A op B" and "A op C" both simplify?
175 if (Value *L = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse))
176 if (Value *R = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse)) {
177 // They do! Return "L op' R" if it simplifies or is already available.
178 // If "L op' R" equals "B op' C" then "L op' R" is just the RHS.
179 if ((L == B && R == C) || (Instruction::isCommutative(OpcodeToExpand)
180 && L == C && R == B)) {
184 // Otherwise return "L op' R" if it simplifies.
185 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
195 /// SimplifyAssociativeBinOp - Generic simplifications for associative binary
196 /// operations. Returns the simpler value, or null if none was found.
197 static Value *SimplifyAssociativeBinOp(unsigned Opc, Value *LHS, Value *RHS,
198 const Query &Q, unsigned MaxRecurse) {
199 Instruction::BinaryOps Opcode = (Instruction::BinaryOps)Opc;
200 assert(Instruction::isAssociative(Opcode) && "Not an associative operation!");
202 // Recursion is always used, so bail out at once if we already hit the limit.
206 BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
207 BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
209 // Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely.
210 if (Op0 && Op0->getOpcode() == Opcode) {
211 Value *A = Op0->getOperand(0);
212 Value *B = Op0->getOperand(1);
215 // Does "B op C" simplify?
216 if (Value *V = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
217 // It does! Return "A op V" if it simplifies or is already available.
218 // If V equals B then "A op V" is just the LHS.
219 if (V == B) return LHS;
220 // Otherwise return "A op V" if it simplifies.
221 if (Value *W = SimplifyBinOp(Opcode, A, V, Q, MaxRecurse)) {
228 // Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely.
229 if (Op1 && Op1->getOpcode() == Opcode) {
231 Value *B = Op1->getOperand(0);
232 Value *C = Op1->getOperand(1);
234 // Does "A op B" simplify?
235 if (Value *V = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse)) {
236 // It does! Return "V op C" if it simplifies or is already available.
237 // If V equals B then "V op C" is just the RHS.
238 if (V == B) return RHS;
239 // Otherwise return "V op C" if it simplifies.
240 if (Value *W = SimplifyBinOp(Opcode, V, C, Q, MaxRecurse)) {
247 // The remaining transforms require commutativity as well as associativity.
248 if (!Instruction::isCommutative(Opcode))
251 // Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely.
252 if (Op0 && Op0->getOpcode() == Opcode) {
253 Value *A = Op0->getOperand(0);
254 Value *B = Op0->getOperand(1);
257 // Does "C op A" simplify?
258 if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
259 // It does! Return "V op B" if it simplifies or is already available.
260 // If V equals A then "V op B" is just the LHS.
261 if (V == A) return LHS;
262 // Otherwise return "V op B" if it simplifies.
263 if (Value *W = SimplifyBinOp(Opcode, V, B, Q, MaxRecurse)) {
270 // Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely.
271 if (Op1 && Op1->getOpcode() == Opcode) {
273 Value *B = Op1->getOperand(0);
274 Value *C = Op1->getOperand(1);
276 // Does "C op A" simplify?
277 if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
278 // It does! Return "B op V" if it simplifies or is already available.
279 // If V equals C then "B op V" is just the RHS.
280 if (V == C) return RHS;
281 // Otherwise return "B op V" if it simplifies.
282 if (Value *W = SimplifyBinOp(Opcode, B, V, Q, MaxRecurse)) {
292 /// ThreadBinOpOverSelect - In the case of a binary operation with a select
293 /// instruction as an operand, try to simplify the binop by seeing whether
294 /// evaluating it on both branches of the select results in the same value.
295 /// Returns the common value if so, otherwise returns null.
296 static Value *ThreadBinOpOverSelect(unsigned Opcode, Value *LHS, Value *RHS,
297 const Query &Q, unsigned MaxRecurse) {
298 // Recursion is always used, so bail out at once if we already hit the limit.
303 if (isa<SelectInst>(LHS)) {
304 SI = cast<SelectInst>(LHS);
306 assert(isa<SelectInst>(RHS) && "No select instruction operand!");
307 SI = cast<SelectInst>(RHS);
310 // Evaluate the BinOp on the true and false branches of the select.
314 TV = SimplifyBinOp(Opcode, SI->getTrueValue(), RHS, Q, MaxRecurse);
315 FV = SimplifyBinOp(Opcode, SI->getFalseValue(), RHS, Q, MaxRecurse);
317 TV = SimplifyBinOp(Opcode, LHS, SI->getTrueValue(), Q, MaxRecurse);
318 FV = SimplifyBinOp(Opcode, LHS, SI->getFalseValue(), Q, MaxRecurse);
321 // If they simplified to the same value, then return the common value.
322 // If they both failed to simplify then return null.
326 // If one branch simplified to undef, return the other one.
327 if (TV && isa<UndefValue>(TV))
329 if (FV && isa<UndefValue>(FV))
332 // If applying the operation did not change the true and false select values,
333 // then the result of the binop is the select itself.
334 if (TV == SI->getTrueValue() && FV == SI->getFalseValue())
337 // If one branch simplified and the other did not, and the simplified
338 // value is equal to the unsimplified one, return the simplified value.
339 // For example, select (cond, X, X & Z) & Z -> X & Z.
340 if ((FV && !TV) || (TV && !FV)) {
341 // Check that the simplified value has the form "X op Y" where "op" is the
342 // same as the original operation.
343 Instruction *Simplified = dyn_cast<Instruction>(FV ? FV : TV);
344 if (Simplified && Simplified->getOpcode() == Opcode) {
345 // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS".
346 // We already know that "op" is the same as for the simplified value. See
347 // if the operands match too. If so, return the simplified value.
348 Value *UnsimplifiedBranch = FV ? SI->getTrueValue() : SI->getFalseValue();
349 Value *UnsimplifiedLHS = SI == LHS ? UnsimplifiedBranch : LHS;
350 Value *UnsimplifiedRHS = SI == LHS ? RHS : UnsimplifiedBranch;
351 if (Simplified->getOperand(0) == UnsimplifiedLHS &&
352 Simplified->getOperand(1) == UnsimplifiedRHS)
354 if (Simplified->isCommutative() &&
355 Simplified->getOperand(1) == UnsimplifiedLHS &&
356 Simplified->getOperand(0) == UnsimplifiedRHS)
364 /// ThreadCmpOverSelect - In the case of a comparison with a select instruction,
365 /// try to simplify the comparison by seeing whether both branches of the select
366 /// result in the same value. Returns the common value if so, otherwise returns
368 static Value *ThreadCmpOverSelect(CmpInst::Predicate Pred, Value *LHS,
369 Value *RHS, const Query &Q,
370 unsigned MaxRecurse) {
371 // Recursion is always used, so bail out at once if we already hit the limit.
375 // Make sure the select is on the LHS.
376 if (!isa<SelectInst>(LHS)) {
378 Pred = CmpInst::getSwappedPredicate(Pred);
380 assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!");
381 SelectInst *SI = cast<SelectInst>(LHS);
382 Value *Cond = SI->getCondition();
383 Value *TV = SI->getTrueValue();
384 Value *FV = SI->getFalseValue();
386 // Now that we have "cmp select(Cond, TV, FV), RHS", analyse it.
387 // Does "cmp TV, RHS" simplify?
388 Value *TCmp = SimplifyCmpInst(Pred, TV, RHS, Q, MaxRecurse);
390 // It not only simplified, it simplified to the select condition. Replace
392 TCmp = getTrue(Cond->getType());
394 // It didn't simplify. However if "cmp TV, RHS" is equal to the select
395 // condition then we can replace it with 'true'. Otherwise give up.
396 if (!isSameCompare(Cond, Pred, TV, RHS))
398 TCmp = getTrue(Cond->getType());
401 // Does "cmp FV, RHS" simplify?
402 Value *FCmp = SimplifyCmpInst(Pred, FV, RHS, Q, MaxRecurse);
404 // It not only simplified, it simplified to the select condition. Replace
406 FCmp = getFalse(Cond->getType());
408 // It didn't simplify. However if "cmp FV, RHS" is equal to the select
409 // condition then we can replace it with 'false'. Otherwise give up.
410 if (!isSameCompare(Cond, Pred, FV, RHS))
412 FCmp = getFalse(Cond->getType());
415 // If both sides simplified to the same value, then use it as the result of
416 // the original comparison.
420 // The remaining cases only make sense if the select condition has the same
421 // type as the result of the comparison, so bail out if this is not so.
422 if (Cond->getType()->isVectorTy() != RHS->getType()->isVectorTy())
424 // If the false value simplified to false, then the result of the compare
425 // is equal to "Cond && TCmp". This also catches the case when the false
426 // value simplified to false and the true value to true, returning "Cond".
427 if (match(FCmp, m_Zero()))
428 if (Value *V = SimplifyAndInst(Cond, TCmp, Q, MaxRecurse))
430 // If the true value simplified to true, then the result of the compare
431 // is equal to "Cond || FCmp".
432 if (match(TCmp, m_One()))
433 if (Value *V = SimplifyOrInst(Cond, FCmp, Q, MaxRecurse))
435 // Finally, if the false value simplified to true and the true value to
436 // false, then the result of the compare is equal to "!Cond".
437 if (match(FCmp, m_One()) && match(TCmp, m_Zero()))
439 SimplifyXorInst(Cond, Constant::getAllOnesValue(Cond->getType()),
446 /// ThreadBinOpOverPHI - In the case of a binary operation with an operand that
447 /// is a PHI instruction, try to simplify the binop by seeing whether evaluating
448 /// it on the incoming phi values yields the same result for every value. If so
449 /// returns the common value, otherwise returns null.
450 static Value *ThreadBinOpOverPHI(unsigned Opcode, Value *LHS, Value *RHS,
451 const Query &Q, unsigned MaxRecurse) {
452 // Recursion is always used, so bail out at once if we already hit the limit.
457 if (isa<PHINode>(LHS)) {
458 PI = cast<PHINode>(LHS);
459 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
460 if (!ValueDominatesPHI(RHS, PI, Q.DT))
463 assert(isa<PHINode>(RHS) && "No PHI instruction operand!");
464 PI = cast<PHINode>(RHS);
465 // Bail out if LHS and the phi may be mutually interdependent due to a loop.
466 if (!ValueDominatesPHI(LHS, PI, Q.DT))
470 // Evaluate the BinOp on the incoming phi values.
471 Value *CommonValue = nullptr;
472 for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
473 Value *Incoming = PI->getIncomingValue(i);
474 // If the incoming value is the phi node itself, it can safely be skipped.
475 if (Incoming == PI) continue;
476 Value *V = PI == LHS ?
477 SimplifyBinOp(Opcode, Incoming, RHS, Q, MaxRecurse) :
478 SimplifyBinOp(Opcode, LHS, Incoming, Q, MaxRecurse);
479 // If the operation failed to simplify, or simplified to a different value
480 // to previously, then give up.
481 if (!V || (CommonValue && V != CommonValue))
489 /// ThreadCmpOverPHI - In the case of a comparison with a PHI instruction, try
490 /// try to simplify the comparison by seeing whether comparing with all of the
491 /// incoming phi values yields the same result every time. If so returns the
492 /// common result, otherwise returns null.
493 static Value *ThreadCmpOverPHI(CmpInst::Predicate Pred, Value *LHS, Value *RHS,
494 const Query &Q, unsigned MaxRecurse) {
495 // Recursion is always used, so bail out at once if we already hit the limit.
499 // Make sure the phi is on the LHS.
500 if (!isa<PHINode>(LHS)) {
502 Pred = CmpInst::getSwappedPredicate(Pred);
504 assert(isa<PHINode>(LHS) && "Not comparing with a phi instruction!");
505 PHINode *PI = cast<PHINode>(LHS);
507 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
508 if (!ValueDominatesPHI(RHS, PI, Q.DT))
511 // Evaluate the BinOp on the incoming phi values.
512 Value *CommonValue = nullptr;
513 for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
514 Value *Incoming = PI->getIncomingValue(i);
515 // If the incoming value is the phi node itself, it can safely be skipped.
516 if (Incoming == PI) continue;
517 Value *V = SimplifyCmpInst(Pred, Incoming, RHS, Q, MaxRecurse);
518 // If the operation failed to simplify, or simplified to a different value
519 // to previously, then give up.
520 if (!V || (CommonValue && V != CommonValue))
528 /// SimplifyAddInst - Given operands for an Add, see if we can
529 /// fold the result. If not, this returns null.
530 static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
531 const Query &Q, unsigned MaxRecurse) {
532 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
533 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
534 Constant *Ops[] = { CLHS, CRHS };
535 return ConstantFoldInstOperands(Instruction::Add, CLHS->getType(), Ops,
539 // Canonicalize the constant to the RHS.
543 // X + undef -> undef
544 if (match(Op1, m_Undef()))
548 if (match(Op1, m_Zero()))
555 if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) ||
556 match(Op0, m_Sub(m_Value(Y), m_Specific(Op1))))
559 // X + ~X -> -1 since ~X = -X-1
560 if (match(Op0, m_Not(m_Specific(Op1))) ||
561 match(Op1, m_Not(m_Specific(Op0))))
562 return Constant::getAllOnesValue(Op0->getType());
565 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
566 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
569 // Try some generic simplifications for associative operations.
570 if (Value *V = SimplifyAssociativeBinOp(Instruction::Add, Op0, Op1, Q,
574 // Threading Add over selects and phi nodes is pointless, so don't bother.
575 // Threading over the select in "A + select(cond, B, C)" means evaluating
576 // "A+B" and "A+C" and seeing if they are equal; but they are equal if and
577 // only if B and C are equal. If B and C are equal then (since we assume
578 // that operands have already been simplified) "select(cond, B, C)" should
579 // have been simplified to the common value of B and C already. Analysing
580 // "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly
581 // for threading over phi nodes.
586 Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
587 const DataLayout *DL, const TargetLibraryInfo *TLI,
588 const DominatorTree *DT, AssumptionCache *AC,
589 const Instruction *CxtI) {
590 return ::SimplifyAddInst(Op0, Op1, isNSW, isNUW, Query(DL, TLI, DT, AC, CxtI),
594 /// \brief Compute the base pointer and cumulative constant offsets for V.
596 /// This strips all constant offsets off of V, leaving it the base pointer, and
597 /// accumulates the total constant offset applied in the returned constant. It
598 /// returns 0 if V is not a pointer, and returns the constant '0' if there are
599 /// no constant offsets applied.
601 /// This is very similar to GetPointerBaseWithConstantOffset except it doesn't
602 /// follow non-inbounds geps. This allows it to remain usable for icmp ult/etc.
604 static Constant *stripAndComputeConstantOffsets(const DataLayout *DL,
606 bool AllowNonInbounds = false) {
607 assert(V->getType()->getScalarType()->isPointerTy());
609 // Without DataLayout, just be conservative for now. Theoretically, more could
610 // be done in this case.
612 return ConstantInt::get(IntegerType::get(V->getContext(), 64), 0);
614 Type *IntPtrTy = DL->getIntPtrType(V->getType())->getScalarType();
615 APInt Offset = APInt::getNullValue(IntPtrTy->getIntegerBitWidth());
617 // Even though we don't look through PHI nodes, we could be called on an
618 // instruction in an unreachable block, which may be on a cycle.
619 SmallPtrSet<Value *, 4> Visited;
622 if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
623 if ((!AllowNonInbounds && !GEP->isInBounds()) ||
624 !GEP->accumulateConstantOffset(*DL, Offset))
626 V = GEP->getPointerOperand();
627 } else if (Operator::getOpcode(V) == Instruction::BitCast) {
628 V = cast<Operator>(V)->getOperand(0);
629 } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
630 if (GA->mayBeOverridden())
632 V = GA->getAliasee();
636 assert(V->getType()->getScalarType()->isPointerTy() &&
637 "Unexpected operand type!");
638 } while (Visited.insert(V).second);
640 Constant *OffsetIntPtr = ConstantInt::get(IntPtrTy, Offset);
641 if (V->getType()->isVectorTy())
642 return ConstantVector::getSplat(V->getType()->getVectorNumElements(),
647 /// \brief Compute the constant difference between two pointer values.
648 /// If the difference is not a constant, returns zero.
649 static Constant *computePointerDifference(const DataLayout *DL,
650 Value *LHS, Value *RHS) {
651 Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
652 Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
654 // If LHS and RHS are not related via constant offsets to the same base
655 // value, there is nothing we can do here.
659 // Otherwise, the difference of LHS - RHS can be computed as:
661 // = (LHSOffset + Base) - (RHSOffset + Base)
662 // = LHSOffset - RHSOffset
663 return ConstantExpr::getSub(LHSOffset, RHSOffset);
666 /// SimplifySubInst - Given operands for a Sub, see if we can
667 /// fold the result. If not, this returns null.
668 static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
669 const Query &Q, unsigned MaxRecurse) {
670 if (Constant *CLHS = dyn_cast<Constant>(Op0))
671 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
672 Constant *Ops[] = { CLHS, CRHS };
673 return ConstantFoldInstOperands(Instruction::Sub, CLHS->getType(),
677 // X - undef -> undef
678 // undef - X -> undef
679 if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
680 return UndefValue::get(Op0->getType());
683 if (match(Op1, m_Zero()))
688 return Constant::getNullValue(Op0->getType());
690 // 0 - X -> 0 if the sub is NUW.
691 if (isNUW && match(Op0, m_Zero()))
694 // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
695 // For example, (X + Y) - Y -> X; (Y + X) - Y -> X
696 Value *X = nullptr, *Y = nullptr, *Z = Op1;
697 if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z
698 // See if "V === Y - Z" simplifies.
699 if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, Q, MaxRecurse-1))
700 // It does! Now see if "X + V" simplifies.
701 if (Value *W = SimplifyBinOp(Instruction::Add, X, V, Q, MaxRecurse-1)) {
702 // It does, we successfully reassociated!
706 // See if "V === X - Z" simplifies.
707 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
708 // It does! Now see if "Y + V" simplifies.
709 if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, Q, MaxRecurse-1)) {
710 // It does, we successfully reassociated!
716 // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
717 // For example, X - (X + 1) -> -1
719 if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z)
720 // See if "V === X - Y" simplifies.
721 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
722 // It does! Now see if "V - Z" simplifies.
723 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, Q, MaxRecurse-1)) {
724 // It does, we successfully reassociated!
728 // See if "V === X - Z" simplifies.
729 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
730 // It does! Now see if "V - Y" simplifies.
731 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, Q, MaxRecurse-1)) {
732 // It does, we successfully reassociated!
738 // Z - (X - Y) -> (Z - X) + Y if everything simplifies.
739 // For example, X - (X - Y) -> Y.
741 if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y)
742 // See if "V === Z - X" simplifies.
743 if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, Q, MaxRecurse-1))
744 // It does! Now see if "V + Y" simplifies.
745 if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, Q, MaxRecurse-1)) {
746 // It does, we successfully reassociated!
751 // trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies.
752 if (MaxRecurse && match(Op0, m_Trunc(m_Value(X))) &&
753 match(Op1, m_Trunc(m_Value(Y))))
754 if (X->getType() == Y->getType())
755 // See if "V === X - Y" simplifies.
756 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
757 // It does! Now see if "trunc V" simplifies.
758 if (Value *W = SimplifyTruncInst(V, Op0->getType(), Q, MaxRecurse-1))
759 // It does, return the simplified "trunc V".
762 // Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...).
763 if (match(Op0, m_PtrToInt(m_Value(X))) &&
764 match(Op1, m_PtrToInt(m_Value(Y))))
765 if (Constant *Result = computePointerDifference(Q.DL, X, Y))
766 return ConstantExpr::getIntegerCast(Result, Op0->getType(), true);
769 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
770 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
773 // Threading Sub over selects and phi nodes is pointless, so don't bother.
774 // Threading over the select in "A - select(cond, B, C)" means evaluating
775 // "A-B" and "A-C" and seeing if they are equal; but they are equal if and
776 // only if B and C are equal. If B and C are equal then (since we assume
777 // that operands have already been simplified) "select(cond, B, C)" should
778 // have been simplified to the common value of B and C already. Analysing
779 // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly
780 // for threading over phi nodes.
785 Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
786 const DataLayout *DL, const TargetLibraryInfo *TLI,
787 const DominatorTree *DT, AssumptionCache *AC,
788 const Instruction *CxtI) {
789 return ::SimplifySubInst(Op0, Op1, isNSW, isNUW, Query(DL, TLI, DT, AC, CxtI),
793 /// Given operands for an FAdd, see if we can fold the result. If not, this
795 static Value *SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
796 const Query &Q, unsigned MaxRecurse) {
797 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
798 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
799 Constant *Ops[] = { CLHS, CRHS };
800 return ConstantFoldInstOperands(Instruction::FAdd, CLHS->getType(),
804 // Canonicalize the constant to the RHS.
809 if (match(Op1, m_NegZero()))
812 // fadd X, 0 ==> X, when we know X is not -0
813 if (match(Op1, m_Zero()) &&
814 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
817 // fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
818 // where nnan and ninf have to occur at least once somewhere in this
820 Value *SubOp = nullptr;
821 if (match(Op1, m_FSub(m_AnyZero(), m_Specific(Op0))))
823 else if (match(Op0, m_FSub(m_AnyZero(), m_Specific(Op1))))
826 Instruction *FSub = cast<Instruction>(SubOp);
827 if ((FMF.noNaNs() || FSub->hasNoNaNs()) &&
828 (FMF.noInfs() || FSub->hasNoInfs()))
829 return Constant::getNullValue(Op0->getType());
835 /// Given operands for an FSub, see if we can fold the result. If not, this
837 static Value *SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
838 const Query &Q, unsigned MaxRecurse) {
839 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
840 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
841 Constant *Ops[] = { CLHS, CRHS };
842 return ConstantFoldInstOperands(Instruction::FSub, CLHS->getType(),
848 if (match(Op1, m_Zero()))
851 // fsub X, -0 ==> X, when we know X is not -0
852 if (match(Op1, m_NegZero()) &&
853 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
856 // fsub 0, (fsub -0.0, X) ==> X
858 if (match(Op0, m_AnyZero())) {
859 if (match(Op1, m_FSub(m_NegZero(), m_Value(X))))
861 if (FMF.noSignedZeros() && match(Op1, m_FSub(m_AnyZero(), m_Value(X))))
865 // fsub nnan ninf x, x ==> 0.0
866 if (FMF.noNaNs() && FMF.noInfs() && Op0 == Op1)
867 return Constant::getNullValue(Op0->getType());
872 /// Given the operands for an FMul, see if we can fold the result
873 static Value *SimplifyFMulInst(Value *Op0, Value *Op1,
876 unsigned MaxRecurse) {
877 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
878 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
879 Constant *Ops[] = { CLHS, CRHS };
880 return ConstantFoldInstOperands(Instruction::FMul, CLHS->getType(),
884 // Canonicalize the constant to the RHS.
889 if (match(Op1, m_FPOne()))
892 // fmul nnan nsz X, 0 ==> 0
893 if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZero()))
899 /// SimplifyMulInst - Given operands for a Mul, see if we can
900 /// fold the result. If not, this returns null.
901 static Value *SimplifyMulInst(Value *Op0, Value *Op1, const Query &Q,
902 unsigned MaxRecurse) {
903 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
904 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
905 Constant *Ops[] = { CLHS, CRHS };
906 return ConstantFoldInstOperands(Instruction::Mul, CLHS->getType(),
910 // Canonicalize the constant to the RHS.
915 if (match(Op1, m_Undef()))
916 return Constant::getNullValue(Op0->getType());
919 if (match(Op1, m_Zero()))
923 if (match(Op1, m_One()))
926 // (X / Y) * Y -> X if the division is exact.
928 if (match(Op0, m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y
929 match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0))))) // Y * (X / Y)
933 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
934 if (Value *V = SimplifyAndInst(Op0, Op1, Q, MaxRecurse-1))
937 // Try some generic simplifications for associative operations.
938 if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, Q,
942 // Mul distributes over Add. Try some generic simplifications based on this.
943 if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add,
947 // If the operation is with the result of a select instruction, check whether
948 // operating on either branch of the select always yields the same value.
949 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
950 if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, Q,
954 // If the operation is with the result of a phi instruction, check whether
955 // operating on all incoming values of the phi always yields the same value.
956 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
957 if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, Q,
964 Value *llvm::SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
965 const DataLayout *DL,
966 const TargetLibraryInfo *TLI,
967 const DominatorTree *DT, AssumptionCache *AC,
968 const Instruction *CxtI) {
969 return ::SimplifyFAddInst(Op0, Op1, FMF, Query(DL, TLI, DT, AC, CxtI),
973 Value *llvm::SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
974 const DataLayout *DL,
975 const TargetLibraryInfo *TLI,
976 const DominatorTree *DT, AssumptionCache *AC,
977 const Instruction *CxtI) {
978 return ::SimplifyFSubInst(Op0, Op1, FMF, Query(DL, TLI, DT, AC, CxtI),
982 Value *llvm::SimplifyFMulInst(Value *Op0, Value *Op1, FastMathFlags FMF,
983 const DataLayout *DL,
984 const TargetLibraryInfo *TLI,
985 const DominatorTree *DT, AssumptionCache *AC,
986 const Instruction *CxtI) {
987 return ::SimplifyFMulInst(Op0, Op1, FMF, Query(DL, TLI, DT, AC, CxtI),
991 Value *llvm::SimplifyMulInst(Value *Op0, Value *Op1, const DataLayout *DL,
992 const TargetLibraryInfo *TLI,
993 const DominatorTree *DT, AssumptionCache *AC,
994 const Instruction *CxtI) {
995 return ::SimplifyMulInst(Op0, Op1, Query(DL, TLI, DT, AC, CxtI),
999 /// SimplifyDiv - Given operands for an SDiv or UDiv, see if we can
1000 /// fold the result. If not, this returns null.
1001 static Value *SimplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
1002 const Query &Q, unsigned MaxRecurse) {
1003 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1004 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1005 Constant *Ops[] = { C0, C1 };
1006 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.DL, Q.TLI);
1010 bool isSigned = Opcode == Instruction::SDiv;
1012 // X / undef -> undef
1013 if (match(Op1, m_Undef()))
1016 // X / 0 -> undef, we don't need to preserve faults!
1017 if (match(Op1, m_Zero()))
1018 return UndefValue::get(Op1->getType());
1021 if (match(Op0, m_Undef()))
1022 return Constant::getNullValue(Op0->getType());
1024 // 0 / X -> 0, we don't need to preserve faults!
1025 if (match(Op0, m_Zero()))
1029 if (match(Op1, m_One()))
1032 if (Op0->getType()->isIntegerTy(1))
1033 // It can't be division by zero, hence it must be division by one.
1038 return ConstantInt::get(Op0->getType(), 1);
1040 // (X * Y) / Y -> X if the multiplication does not overflow.
1041 Value *X = nullptr, *Y = nullptr;
1042 if (match(Op0, m_Mul(m_Value(X), m_Value(Y))) && (X == Op1 || Y == Op1)) {
1043 if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1
1044 OverflowingBinaryOperator *Mul = cast<OverflowingBinaryOperator>(Op0);
1045 // If the Mul knows it does not overflow, then we are good to go.
1046 if ((isSigned && Mul->hasNoSignedWrap()) ||
1047 (!isSigned && Mul->hasNoUnsignedWrap()))
1049 // If X has the form X = A / Y then X * Y cannot overflow.
1050 if (BinaryOperator *Div = dyn_cast<BinaryOperator>(X))
1051 if (Div->getOpcode() == Opcode && Div->getOperand(1) == Y)
1055 // (X rem Y) / Y -> 0
1056 if ((isSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1057 (!isSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1058 return Constant::getNullValue(Op0->getType());
1060 // (X /u C1) /u C2 -> 0 if C1 * C2 overflow
1061 ConstantInt *C1, *C2;
1062 if (!isSigned && match(Op0, m_UDiv(m_Value(X), m_ConstantInt(C1))) &&
1063 match(Op1, m_ConstantInt(C2))) {
1065 C1->getValue().umul_ov(C2->getValue(), Overflow);
1067 return Constant::getNullValue(Op0->getType());
1070 // If the operation is with the result of a select instruction, check whether
1071 // operating on either branch of the select always yields the same value.
1072 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1073 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1076 // If the operation is with the result of a phi instruction, check whether
1077 // operating on all incoming values of the phi always yields the same value.
1078 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1079 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1085 /// SimplifySDivInst - Given operands for an SDiv, see if we can
1086 /// fold the result. If not, this returns null.
1087 static Value *SimplifySDivInst(Value *Op0, Value *Op1, const Query &Q,
1088 unsigned MaxRecurse) {
1089 if (Value *V = SimplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse))
1095 Value *llvm::SimplifySDivInst(Value *Op0, Value *Op1, const DataLayout *DL,
1096 const TargetLibraryInfo *TLI,
1097 const DominatorTree *DT, AssumptionCache *AC,
1098 const Instruction *CxtI) {
1099 return ::SimplifySDivInst(Op0, Op1, Query(DL, TLI, DT, AC, CxtI),
1103 /// SimplifyUDivInst - Given operands for a UDiv, see if we can
1104 /// fold the result. If not, this returns null.
1105 static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const Query &Q,
1106 unsigned MaxRecurse) {
1107 if (Value *V = SimplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse))
1113 Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const DataLayout *DL,
1114 const TargetLibraryInfo *TLI,
1115 const DominatorTree *DT, AssumptionCache *AC,
1116 const Instruction *CxtI) {
1117 return ::SimplifyUDivInst(Op0, Op1, Query(DL, TLI, DT, AC, CxtI),
1121 static Value *SimplifyFDivInst(Value *Op0, Value *Op1, FastMathFlags FMF,
1122 const Query &Q, unsigned) {
1123 // undef / X -> undef (the undef could be a snan).
1124 if (match(Op0, m_Undef()))
1127 // X / undef -> undef
1128 if (match(Op1, m_Undef()))
1132 // Requires that NaNs are off (X could be zero) and signed zeroes are
1133 // ignored (X could be positive or negative, so the output sign is unknown).
1134 if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op0, m_AnyZero()))
1140 Value *llvm::SimplifyFDivInst(Value *Op0, Value *Op1, FastMathFlags FMF,
1141 const DataLayout *DL,
1142 const TargetLibraryInfo *TLI,
1143 const DominatorTree *DT, AssumptionCache *AC,
1144 const Instruction *CxtI) {
1145 return ::SimplifyFDivInst(Op0, Op1, FMF, Query(DL, TLI, DT, AC, CxtI),
1149 /// SimplifyRem - Given operands for an SRem or URem, see if we can
1150 /// fold the result. If not, this returns null.
1151 static Value *SimplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
1152 const Query &Q, unsigned MaxRecurse) {
1153 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1154 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1155 Constant *Ops[] = { C0, C1 };
1156 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.DL, Q.TLI);
1160 // X % undef -> undef
1161 if (match(Op1, m_Undef()))
1165 if (match(Op0, m_Undef()))
1166 return Constant::getNullValue(Op0->getType());
1168 // 0 % X -> 0, we don't need to preserve faults!
1169 if (match(Op0, m_Zero()))
1172 // X % 0 -> undef, we don't need to preserve faults!
1173 if (match(Op1, m_Zero()))
1174 return UndefValue::get(Op0->getType());
1177 if (match(Op1, m_One()))
1178 return Constant::getNullValue(Op0->getType());
1180 if (Op0->getType()->isIntegerTy(1))
1181 // It can't be remainder by zero, hence it must be remainder by one.
1182 return Constant::getNullValue(Op0->getType());
1186 return Constant::getNullValue(Op0->getType());
1188 // (X % Y) % Y -> X % Y
1189 if ((Opcode == Instruction::SRem &&
1190 match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1191 (Opcode == Instruction::URem &&
1192 match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1195 // If the operation is with the result of a select instruction, check whether
1196 // operating on either branch of the select always yields the same value.
1197 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1198 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1201 // If the operation is with the result of a phi instruction, check whether
1202 // operating on all incoming values of the phi always yields the same value.
1203 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1204 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1210 /// SimplifySRemInst - Given operands for an SRem, see if we can
1211 /// fold the result. If not, this returns null.
1212 static Value *SimplifySRemInst(Value *Op0, Value *Op1, const Query &Q,
1213 unsigned MaxRecurse) {
1214 if (Value *V = SimplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse))
1220 Value *llvm::SimplifySRemInst(Value *Op0, Value *Op1, const DataLayout *DL,
1221 const TargetLibraryInfo *TLI,
1222 const DominatorTree *DT, AssumptionCache *AC,
1223 const Instruction *CxtI) {
1224 return ::SimplifySRemInst(Op0, Op1, Query(DL, TLI, DT, AC, CxtI),
1228 /// SimplifyURemInst - Given operands for a URem, see if we can
1229 /// fold the result. If not, this returns null.
1230 static Value *SimplifyURemInst(Value *Op0, Value *Op1, const Query &Q,
1231 unsigned MaxRecurse) {
1232 if (Value *V = SimplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse))
1238 Value *llvm::SimplifyURemInst(Value *Op0, Value *Op1, const DataLayout *DL,
1239 const TargetLibraryInfo *TLI,
1240 const DominatorTree *DT, AssumptionCache *AC,
1241 const Instruction *CxtI) {
1242 return ::SimplifyURemInst(Op0, Op1, Query(DL, TLI, DT, AC, CxtI),
1246 static Value *SimplifyFRemInst(Value *Op0, Value *Op1, FastMathFlags FMF,
1247 const Query &, unsigned) {
1248 // undef % X -> undef (the undef could be a snan).
1249 if (match(Op0, m_Undef()))
1252 // X % undef -> undef
1253 if (match(Op1, m_Undef()))
1257 // Requires that NaNs are off (X could be zero) and signed zeroes are
1258 // ignored (X could be positive or negative, so the output sign is unknown).
1259 if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op0, m_AnyZero()))
1265 Value *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, FastMathFlags FMF,
1266 const DataLayout *DL,
1267 const TargetLibraryInfo *TLI,
1268 const DominatorTree *DT, AssumptionCache *AC,
1269 const Instruction *CxtI) {
1270 return ::SimplifyFRemInst(Op0, Op1, FMF, Query(DL, TLI, DT, AC, CxtI),
1274 /// isUndefShift - Returns true if a shift by \c Amount always yields undef.
1275 static bool isUndefShift(Value *Amount) {
1276 Constant *C = dyn_cast<Constant>(Amount);
1280 // X shift by undef -> undef because it may shift by the bitwidth.
1281 if (isa<UndefValue>(C))
1284 // Shifting by the bitwidth or more is undefined.
1285 if (ConstantInt *CI = dyn_cast<ConstantInt>(C))
1286 if (CI->getValue().getLimitedValue() >=
1287 CI->getType()->getScalarSizeInBits())
1290 // If all lanes of a vector shift are undefined the whole shift is.
1291 if (isa<ConstantVector>(C) || isa<ConstantDataVector>(C)) {
1292 for (unsigned I = 0, E = C->getType()->getVectorNumElements(); I != E; ++I)
1293 if (!isUndefShift(C->getAggregateElement(I)))
1301 /// SimplifyShift - Given operands for an Shl, LShr or AShr, see if we can
1302 /// fold the result. If not, this returns null.
1303 static Value *SimplifyShift(unsigned Opcode, Value *Op0, Value *Op1,
1304 const Query &Q, unsigned MaxRecurse) {
1305 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1306 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1307 Constant *Ops[] = { C0, C1 };
1308 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.DL, Q.TLI);
1312 // 0 shift by X -> 0
1313 if (match(Op0, m_Zero()))
1316 // X shift by 0 -> X
1317 if (match(Op1, m_Zero()))
1320 // Fold undefined shifts.
1321 if (isUndefShift(Op1))
1322 return UndefValue::get(Op0->getType());
1324 // If the operation is with the result of a select instruction, check whether
1325 // operating on either branch of the select always yields the same value.
1326 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1327 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1330 // If the operation is with the result of a phi instruction, check whether
1331 // operating on all incoming values of the phi always yields the same value.
1332 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1333 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1339 /// \brief Given operands for an Shl, LShr or AShr, see if we can
1340 /// fold the result. If not, this returns null.
1341 static Value *SimplifyRightShift(unsigned Opcode, Value *Op0, Value *Op1,
1342 bool isExact, const Query &Q,
1343 unsigned MaxRecurse) {
1344 if (Value *V = SimplifyShift(Opcode, Op0, Op1, Q, MaxRecurse))
1349 return Constant::getNullValue(Op0->getType());
1352 // undef >> X -> undef (if it's exact)
1353 if (match(Op0, m_Undef()))
1354 return isExact ? Op0 : Constant::getNullValue(Op0->getType());
1356 // The low bit cannot be shifted out of an exact shift if it is set.
1358 unsigned BitWidth = Op0->getType()->getScalarSizeInBits();
1359 APInt Op0KnownZero(BitWidth, 0);
1360 APInt Op0KnownOne(BitWidth, 0);
1361 computeKnownBits(Op0, Op0KnownZero, Op0KnownOne, Q.DL, /*Depth=*/0, Q.AC,
1370 /// SimplifyShlInst - Given operands for an Shl, see if we can
1371 /// fold the result. If not, this returns null.
1372 static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1373 const Query &Q, unsigned MaxRecurse) {
1374 if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse))
1378 // undef << X -> undef if (if it's NSW/NUW)
1379 if (match(Op0, m_Undef()))
1380 return isNSW || isNUW ? Op0 : Constant::getNullValue(Op0->getType());
1382 // (X >> A) << A -> X
1384 if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
1389 Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1390 const DataLayout *DL, const TargetLibraryInfo *TLI,
1391 const DominatorTree *DT, AssumptionCache *AC,
1392 const Instruction *CxtI) {
1393 return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Query(DL, TLI, DT, AC, CxtI),
1397 /// SimplifyLShrInst - Given operands for an LShr, see if we can
1398 /// fold the result. If not, this returns null.
1399 static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1400 const Query &Q, unsigned MaxRecurse) {
1401 if (Value *V = SimplifyRightShift(Instruction::LShr, Op0, Op1, isExact, Q,
1405 // (X << A) >> A -> X
1407 if (match(Op0, m_NUWShl(m_Value(X), m_Specific(Op1))))
1413 Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1414 const DataLayout *DL,
1415 const TargetLibraryInfo *TLI,
1416 const DominatorTree *DT, AssumptionCache *AC,
1417 const Instruction *CxtI) {
1418 return ::SimplifyLShrInst(Op0, Op1, isExact, Query(DL, TLI, DT, AC, CxtI),
1422 /// SimplifyAShrInst - Given operands for an AShr, see if we can
1423 /// fold the result. If not, this returns null.
1424 static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1425 const Query &Q, unsigned MaxRecurse) {
1426 if (Value *V = SimplifyRightShift(Instruction::AShr, Op0, Op1, isExact, Q,
1430 // all ones >>a X -> all ones
1431 if (match(Op0, m_AllOnes()))
1434 // (X << A) >> A -> X
1436 if (match(Op0, m_NSWShl(m_Value(X), m_Specific(Op1))))
1439 // Arithmetic shifting an all-sign-bit value is a no-op.
1440 unsigned NumSignBits = ComputeNumSignBits(Op0, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
1441 if (NumSignBits == Op0->getType()->getScalarSizeInBits())
1447 Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1448 const DataLayout *DL,
1449 const TargetLibraryInfo *TLI,
1450 const DominatorTree *DT, AssumptionCache *AC,
1451 const Instruction *CxtI) {
1452 return ::SimplifyAShrInst(Op0, Op1, isExact, Query(DL, TLI, DT, AC, CxtI),
1456 static Value *simplifyUnsignedRangeCheck(ICmpInst *ZeroICmp,
1457 ICmpInst *UnsignedICmp, bool IsAnd) {
1460 ICmpInst::Predicate EqPred;
1461 if (!match(ZeroICmp, m_ICmp(EqPred, m_Value(Y), m_Zero())) ||
1462 !ICmpInst::isEquality(EqPred))
1465 ICmpInst::Predicate UnsignedPred;
1466 if (match(UnsignedICmp, m_ICmp(UnsignedPred, m_Value(X), m_Specific(Y))) &&
1467 ICmpInst::isUnsigned(UnsignedPred))
1469 else if (match(UnsignedICmp,
1470 m_ICmp(UnsignedPred, m_Value(Y), m_Specific(X))) &&
1471 ICmpInst::isUnsigned(UnsignedPred))
1472 UnsignedPred = ICmpInst::getSwappedPredicate(UnsignedPred);
1476 // X < Y && Y != 0 --> X < Y
1477 // X < Y || Y != 0 --> Y != 0
1478 if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_NE)
1479 return IsAnd ? UnsignedICmp : ZeroICmp;
1481 // X >= Y || Y != 0 --> true
1482 // X >= Y || Y == 0 --> X >= Y
1483 if (UnsignedPred == ICmpInst::ICMP_UGE && !IsAnd) {
1484 if (EqPred == ICmpInst::ICMP_NE)
1485 return getTrue(UnsignedICmp->getType());
1486 return UnsignedICmp;
1489 // X < Y && Y == 0 --> false
1490 if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_EQ &&
1492 return getFalse(UnsignedICmp->getType());
1497 // Simplify (and (icmp ...) (icmp ...)) to true when we can tell that the range
1498 // of possible values cannot be satisfied.
1499 static Value *SimplifyAndOfICmps(ICmpInst *Op0, ICmpInst *Op1) {
1500 ICmpInst::Predicate Pred0, Pred1;
1501 ConstantInt *CI1, *CI2;
1504 if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/true))
1507 if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_ConstantInt(CI1)),
1508 m_ConstantInt(CI2))))
1511 if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Specific(CI1))))
1514 Type *ITy = Op0->getType();
1516 auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1517 bool isNSW = AddInst->hasNoSignedWrap();
1518 bool isNUW = AddInst->hasNoUnsignedWrap();
1520 const APInt &CI1V = CI1->getValue();
1521 const APInt &CI2V = CI2->getValue();
1522 const APInt Delta = CI2V - CI1V;
1523 if (CI1V.isStrictlyPositive()) {
1525 if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_SGT)
1526 return getFalse(ITy);
1527 if (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1528 return getFalse(ITy);
1531 if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_SGT)
1532 return getFalse(ITy);
1533 if (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1534 return getFalse(ITy);
1537 if (CI1V.getBoolValue() && isNUW) {
1539 if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT)
1540 return getFalse(ITy);
1542 if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGT)
1543 return getFalse(ITy);
1549 /// SimplifyAndInst - Given operands for an And, see if we can
1550 /// fold the result. If not, this returns null.
1551 static Value *SimplifyAndInst(Value *Op0, Value *Op1, const Query &Q,
1552 unsigned MaxRecurse) {
1553 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1554 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1555 Constant *Ops[] = { CLHS, CRHS };
1556 return ConstantFoldInstOperands(Instruction::And, CLHS->getType(),
1560 // Canonicalize the constant to the RHS.
1561 std::swap(Op0, Op1);
1565 if (match(Op1, m_Undef()))
1566 return Constant::getNullValue(Op0->getType());
1573 if (match(Op1, m_Zero()))
1577 if (match(Op1, m_AllOnes()))
1580 // A & ~A = ~A & A = 0
1581 if (match(Op0, m_Not(m_Specific(Op1))) ||
1582 match(Op1, m_Not(m_Specific(Op0))))
1583 return Constant::getNullValue(Op0->getType());
1586 Value *A = nullptr, *B = nullptr;
1587 if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
1588 (A == Op1 || B == Op1))
1592 if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
1593 (A == Op0 || B == Op0))
1596 // A & (-A) = A if A is a power of two or zero.
1597 if (match(Op0, m_Neg(m_Specific(Op1))) ||
1598 match(Op1, m_Neg(m_Specific(Op0)))) {
1599 if (isKnownToBeAPowerOfTwo(Op0, /*OrZero*/ true, 0, Q.AC, Q.CxtI, Q.DT))
1601 if (isKnownToBeAPowerOfTwo(Op1, /*OrZero*/ true, 0, Q.AC, Q.CxtI, Q.DT))
1605 if (auto *ICILHS = dyn_cast<ICmpInst>(Op0)) {
1606 if (auto *ICIRHS = dyn_cast<ICmpInst>(Op1)) {
1607 if (Value *V = SimplifyAndOfICmps(ICILHS, ICIRHS))
1609 if (Value *V = SimplifyAndOfICmps(ICIRHS, ICILHS))
1614 // Try some generic simplifications for associative operations.
1615 if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
1619 // And distributes over Or. Try some generic simplifications based on this.
1620 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1624 // And distributes over Xor. Try some generic simplifications based on this.
1625 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
1629 // If the operation is with the result of a select instruction, check whether
1630 // operating on either branch of the select always yields the same value.
1631 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1632 if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
1636 // If the operation is with the result of a phi instruction, check whether
1637 // operating on all incoming values of the phi always yields the same value.
1638 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1639 if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
1646 Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const DataLayout *DL,
1647 const TargetLibraryInfo *TLI,
1648 const DominatorTree *DT, AssumptionCache *AC,
1649 const Instruction *CxtI) {
1650 return ::SimplifyAndInst(Op0, Op1, Query(DL, TLI, DT, AC, CxtI),
1654 // Simplify (or (icmp ...) (icmp ...)) to true when we can tell that the union
1655 // contains all possible values.
1656 static Value *SimplifyOrOfICmps(ICmpInst *Op0, ICmpInst *Op1) {
1657 ICmpInst::Predicate Pred0, Pred1;
1658 ConstantInt *CI1, *CI2;
1661 if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/false))
1664 if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_ConstantInt(CI1)),
1665 m_ConstantInt(CI2))))
1668 if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Specific(CI1))))
1671 Type *ITy = Op0->getType();
1673 auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1674 bool isNSW = AddInst->hasNoSignedWrap();
1675 bool isNUW = AddInst->hasNoUnsignedWrap();
1677 const APInt &CI1V = CI1->getValue();
1678 const APInt &CI2V = CI2->getValue();
1679 const APInt Delta = CI2V - CI1V;
1680 if (CI1V.isStrictlyPositive()) {
1682 if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_SLE)
1683 return getTrue(ITy);
1684 if (Pred0 == ICmpInst::ICMP_SGE && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1685 return getTrue(ITy);
1688 if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_SLE)
1689 return getTrue(ITy);
1690 if (Pred0 == ICmpInst::ICMP_SGT && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1691 return getTrue(ITy);
1694 if (CI1V.getBoolValue() && isNUW) {
1696 if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_ULE)
1697 return getTrue(ITy);
1699 if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_ULE)
1700 return getTrue(ITy);
1706 /// SimplifyOrInst - Given operands for an Or, see if we can
1707 /// fold the result. If not, this returns null.
1708 static Value *SimplifyOrInst(Value *Op0, Value *Op1, const Query &Q,
1709 unsigned MaxRecurse) {
1710 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1711 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1712 Constant *Ops[] = { CLHS, CRHS };
1713 return ConstantFoldInstOperands(Instruction::Or, CLHS->getType(),
1717 // Canonicalize the constant to the RHS.
1718 std::swap(Op0, Op1);
1722 if (match(Op1, m_Undef()))
1723 return Constant::getAllOnesValue(Op0->getType());
1730 if (match(Op1, m_Zero()))
1734 if (match(Op1, m_AllOnes()))
1737 // A | ~A = ~A | A = -1
1738 if (match(Op0, m_Not(m_Specific(Op1))) ||
1739 match(Op1, m_Not(m_Specific(Op0))))
1740 return Constant::getAllOnesValue(Op0->getType());
1743 Value *A = nullptr, *B = nullptr;
1744 if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
1745 (A == Op1 || B == Op1))
1749 if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
1750 (A == Op0 || B == Op0))
1753 // ~(A & ?) | A = -1
1754 if (match(Op0, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1755 (A == Op1 || B == Op1))
1756 return Constant::getAllOnesValue(Op1->getType());
1758 // A | ~(A & ?) = -1
1759 if (match(Op1, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1760 (A == Op0 || B == Op0))
1761 return Constant::getAllOnesValue(Op0->getType());
1763 if (auto *ICILHS = dyn_cast<ICmpInst>(Op0)) {
1764 if (auto *ICIRHS = dyn_cast<ICmpInst>(Op1)) {
1765 if (Value *V = SimplifyOrOfICmps(ICILHS, ICIRHS))
1767 if (Value *V = SimplifyOrOfICmps(ICIRHS, ICILHS))
1772 // Try some generic simplifications for associative operations.
1773 if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
1777 // Or distributes over And. Try some generic simplifications based on this.
1778 if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
1782 // If the operation is with the result of a select instruction, check whether
1783 // operating on either branch of the select always yields the same value.
1784 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1785 if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
1790 Value *C = nullptr, *D = nullptr;
1791 if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
1792 match(Op1, m_And(m_Value(B), m_Value(D)))) {
1793 ConstantInt *C1 = dyn_cast<ConstantInt>(C);
1794 ConstantInt *C2 = dyn_cast<ConstantInt>(D);
1795 if (C1 && C2 && (C1->getValue() == ~C2->getValue())) {
1796 // (A & C1)|(B & C2)
1797 // If we have: ((V + N) & C1) | (V & C2)
1798 // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
1799 // replace with V+N.
1801 if ((C2->getValue() & (C2->getValue() + 1)) == 0 && // C2 == 0+1+
1802 match(A, m_Add(m_Value(V1), m_Value(V2)))) {
1803 // Add commutes, try both ways.
1805 MaskedValueIsZero(V2, C2->getValue(), Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
1808 MaskedValueIsZero(V1, C2->getValue(), Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
1811 // Or commutes, try both ways.
1812 if ((C1->getValue() & (C1->getValue() + 1)) == 0 &&
1813 match(B, m_Add(m_Value(V1), m_Value(V2)))) {
1814 // Add commutes, try both ways.
1816 MaskedValueIsZero(V2, C1->getValue(), Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
1819 MaskedValueIsZero(V1, C1->getValue(), Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
1825 // If the operation is with the result of a phi instruction, check whether
1826 // operating on all incoming values of the phi always yields the same value.
1827 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1828 if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
1834 Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const DataLayout *DL,
1835 const TargetLibraryInfo *TLI,
1836 const DominatorTree *DT, AssumptionCache *AC,
1837 const Instruction *CxtI) {
1838 return ::SimplifyOrInst(Op0, Op1, Query(DL, TLI, DT, AC, CxtI),
1842 /// SimplifyXorInst - Given operands for a Xor, see if we can
1843 /// fold the result. If not, this returns null.
1844 static Value *SimplifyXorInst(Value *Op0, Value *Op1, const Query &Q,
1845 unsigned MaxRecurse) {
1846 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1847 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1848 Constant *Ops[] = { CLHS, CRHS };
1849 return ConstantFoldInstOperands(Instruction::Xor, CLHS->getType(),
1853 // Canonicalize the constant to the RHS.
1854 std::swap(Op0, Op1);
1857 // A ^ undef -> undef
1858 if (match(Op1, m_Undef()))
1862 if (match(Op1, m_Zero()))
1867 return Constant::getNullValue(Op0->getType());
1869 // A ^ ~A = ~A ^ A = -1
1870 if (match(Op0, m_Not(m_Specific(Op1))) ||
1871 match(Op1, m_Not(m_Specific(Op0))))
1872 return Constant::getAllOnesValue(Op0->getType());
1874 // Try some generic simplifications for associative operations.
1875 if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
1879 // Threading Xor over selects and phi nodes is pointless, so don't bother.
1880 // Threading over the select in "A ^ select(cond, B, C)" means evaluating
1881 // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
1882 // only if B and C are equal. If B and C are equal then (since we assume
1883 // that operands have already been simplified) "select(cond, B, C)" should
1884 // have been simplified to the common value of B and C already. Analysing
1885 // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
1886 // for threading over phi nodes.
1891 Value *llvm::SimplifyXorInst(Value *Op0, Value *Op1, const DataLayout *DL,
1892 const TargetLibraryInfo *TLI,
1893 const DominatorTree *DT, AssumptionCache *AC,
1894 const Instruction *CxtI) {
1895 return ::SimplifyXorInst(Op0, Op1, Query(DL, TLI, DT, AC, CxtI),
1899 static Type *GetCompareTy(Value *Op) {
1900 return CmpInst::makeCmpResultType(Op->getType());
1903 /// ExtractEquivalentCondition - Rummage around inside V looking for something
1904 /// equivalent to the comparison "LHS Pred RHS". Return such a value if found,
1905 /// otherwise return null. Helper function for analyzing max/min idioms.
1906 static Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred,
1907 Value *LHS, Value *RHS) {
1908 SelectInst *SI = dyn_cast<SelectInst>(V);
1911 CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
1914 Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
1915 if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
1917 if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
1918 LHS == CmpRHS && RHS == CmpLHS)
1923 // A significant optimization not implemented here is assuming that alloca
1924 // addresses are not equal to incoming argument values. They don't *alias*,
1925 // as we say, but that doesn't mean they aren't equal, so we take a
1926 // conservative approach.
1928 // This is inspired in part by C++11 5.10p1:
1929 // "Two pointers of the same type compare equal if and only if they are both
1930 // null, both point to the same function, or both represent the same
1933 // This is pretty permissive.
1935 // It's also partly due to C11 6.5.9p6:
1936 // "Two pointers compare equal if and only if both are null pointers, both are
1937 // pointers to the same object (including a pointer to an object and a
1938 // subobject at its beginning) or function, both are pointers to one past the
1939 // last element of the same array object, or one is a pointer to one past the
1940 // end of one array object and the other is a pointer to the start of a
1941 // different array object that happens to immediately follow the first array
1942 // object in the address space.)
1944 // C11's version is more restrictive, however there's no reason why an argument
1945 // couldn't be a one-past-the-end value for a stack object in the caller and be
1946 // equal to the beginning of a stack object in the callee.
1948 // If the C and C++ standards are ever made sufficiently restrictive in this
1949 // area, it may be possible to update LLVM's semantics accordingly and reinstate
1950 // this optimization.
1951 static Constant *computePointerICmp(const DataLayout *DL,
1952 const TargetLibraryInfo *TLI,
1953 CmpInst::Predicate Pred,
1954 Value *LHS, Value *RHS) {
1955 // First, skip past any trivial no-ops.
1956 LHS = LHS->stripPointerCasts();
1957 RHS = RHS->stripPointerCasts();
1959 // A non-null pointer is not equal to a null pointer.
1960 if (llvm::isKnownNonNull(LHS, TLI) && isa<ConstantPointerNull>(RHS) &&
1961 (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE))
1962 return ConstantInt::get(GetCompareTy(LHS),
1963 !CmpInst::isTrueWhenEqual(Pred));
1965 // We can only fold certain predicates on pointer comparisons.
1970 // Equality comaprisons are easy to fold.
1971 case CmpInst::ICMP_EQ:
1972 case CmpInst::ICMP_NE:
1975 // We can only handle unsigned relational comparisons because 'inbounds' on
1976 // a GEP only protects against unsigned wrapping.
1977 case CmpInst::ICMP_UGT:
1978 case CmpInst::ICMP_UGE:
1979 case CmpInst::ICMP_ULT:
1980 case CmpInst::ICMP_ULE:
1981 // However, we have to switch them to their signed variants to handle
1982 // negative indices from the base pointer.
1983 Pred = ICmpInst::getSignedPredicate(Pred);
1987 // Strip off any constant offsets so that we can reason about them.
1988 // It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets
1989 // here and compare base addresses like AliasAnalysis does, however there are
1990 // numerous hazards. AliasAnalysis and its utilities rely on special rules
1991 // governing loads and stores which don't apply to icmps. Also, AliasAnalysis
1992 // doesn't need to guarantee pointer inequality when it says NoAlias.
1993 Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
1994 Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
1996 // If LHS and RHS are related via constant offsets to the same base
1997 // value, we can replace it with an icmp which just compares the offsets.
1999 return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset);
2001 // Various optimizations for (in)equality comparisons.
2002 if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE) {
2003 // Different non-empty allocations that exist at the same time have
2004 // different addresses (if the program can tell). Global variables always
2005 // exist, so they always exist during the lifetime of each other and all
2006 // allocas. Two different allocas usually have different addresses...
2008 // However, if there's an @llvm.stackrestore dynamically in between two
2009 // allocas, they may have the same address. It's tempting to reduce the
2010 // scope of the problem by only looking at *static* allocas here. That would
2011 // cover the majority of allocas while significantly reducing the likelihood
2012 // of having an @llvm.stackrestore pop up in the middle. However, it's not
2013 // actually impossible for an @llvm.stackrestore to pop up in the middle of
2014 // an entry block. Also, if we have a block that's not attached to a
2015 // function, we can't tell if it's "static" under the current definition.
2016 // Theoretically, this problem could be fixed by creating a new kind of
2017 // instruction kind specifically for static allocas. Such a new instruction
2018 // could be required to be at the top of the entry block, thus preventing it
2019 // from being subject to a @llvm.stackrestore. Instcombine could even
2020 // convert regular allocas into these special allocas. It'd be nifty.
2021 // However, until then, this problem remains open.
2023 // So, we'll assume that two non-empty allocas have different addresses
2026 // With all that, if the offsets are within the bounds of their allocations
2027 // (and not one-past-the-end! so we can't use inbounds!), and their
2028 // allocations aren't the same, the pointers are not equal.
2030 // Note that it's not necessary to check for LHS being a global variable
2031 // address, due to canonicalization and constant folding.
2032 if (isa<AllocaInst>(LHS) &&
2033 (isa<AllocaInst>(RHS) || isa<GlobalVariable>(RHS))) {
2034 ConstantInt *LHSOffsetCI = dyn_cast<ConstantInt>(LHSOffset);
2035 ConstantInt *RHSOffsetCI = dyn_cast<ConstantInt>(RHSOffset);
2036 uint64_t LHSSize, RHSSize;
2037 if (LHSOffsetCI && RHSOffsetCI &&
2038 getObjectSize(LHS, LHSSize, DL, TLI) &&
2039 getObjectSize(RHS, RHSSize, DL, TLI)) {
2040 const APInt &LHSOffsetValue = LHSOffsetCI->getValue();
2041 const APInt &RHSOffsetValue = RHSOffsetCI->getValue();
2042 if (!LHSOffsetValue.isNegative() &&
2043 !RHSOffsetValue.isNegative() &&
2044 LHSOffsetValue.ult(LHSSize) &&
2045 RHSOffsetValue.ult(RHSSize)) {
2046 return ConstantInt::get(GetCompareTy(LHS),
2047 !CmpInst::isTrueWhenEqual(Pred));
2051 // Repeat the above check but this time without depending on DataLayout
2052 // or being able to compute a precise size.
2053 if (!cast<PointerType>(LHS->getType())->isEmptyTy() &&
2054 !cast<PointerType>(RHS->getType())->isEmptyTy() &&
2055 LHSOffset->isNullValue() &&
2056 RHSOffset->isNullValue())
2057 return ConstantInt::get(GetCompareTy(LHS),
2058 !CmpInst::isTrueWhenEqual(Pred));
2061 // Even if an non-inbounds GEP occurs along the path we can still optimize
2062 // equality comparisons concerning the result. We avoid walking the whole
2063 // chain again by starting where the last calls to
2064 // stripAndComputeConstantOffsets left off and accumulate the offsets.
2065 Constant *LHSNoBound = stripAndComputeConstantOffsets(DL, LHS, true);
2066 Constant *RHSNoBound = stripAndComputeConstantOffsets(DL, RHS, true);
2068 return ConstantExpr::getICmp(Pred,
2069 ConstantExpr::getAdd(LHSOffset, LHSNoBound),
2070 ConstantExpr::getAdd(RHSOffset, RHSNoBound));
2072 // If one side of the equality comparison must come from a noalias call
2073 // (meaning a system memory allocation function), and the other side must
2074 // come from a pointer that cannot overlap with dynamically-allocated
2075 // memory within the lifetime of the current function (allocas, byval
2076 // arguments, globals), then determine the comparison result here.
2077 SmallVector<Value *, 8> LHSUObjs, RHSUObjs;
2078 GetUnderlyingObjects(LHS, LHSUObjs, DL);
2079 GetUnderlyingObjects(RHS, RHSUObjs, DL);
2081 // Is the set of underlying objects all noalias calls?
2082 auto IsNAC = [](SmallVectorImpl<Value *> &Objects) {
2083 return std::all_of(Objects.begin(), Objects.end(),
2084 [](Value *V){ return isNoAliasCall(V); });
2087 // Is the set of underlying objects all things which must be disjoint from
2088 // noalias calls. For allocas, we consider only static ones (dynamic
2089 // allocas might be transformed into calls to malloc not simultaneously
2090 // live with the compared-to allocation). For globals, we exclude symbols
2091 // that might be resolve lazily to symbols in another dynamically-loaded
2092 // library (and, thus, could be malloc'ed by the implementation).
2093 auto IsAllocDisjoint = [](SmallVectorImpl<Value *> &Objects) {
2094 return std::all_of(Objects.begin(), Objects.end(),
2096 if (const AllocaInst *AI = dyn_cast<AllocaInst>(V))
2097 return AI->getParent() && AI->getParent()->getParent() &&
2098 AI->isStaticAlloca();
2099 if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
2100 return (GV->hasLocalLinkage() ||
2101 GV->hasHiddenVisibility() ||
2102 GV->hasProtectedVisibility() ||
2103 GV->hasUnnamedAddr()) &&
2104 !GV->isThreadLocal();
2105 if (const Argument *A = dyn_cast<Argument>(V))
2106 return A->hasByValAttr();
2111 if ((IsNAC(LHSUObjs) && IsAllocDisjoint(RHSUObjs)) ||
2112 (IsNAC(RHSUObjs) && IsAllocDisjoint(LHSUObjs)))
2113 return ConstantInt::get(GetCompareTy(LHS),
2114 !CmpInst::isTrueWhenEqual(Pred));
2121 /// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
2122 /// fold the result. If not, this returns null.
2123 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2124 const Query &Q, unsigned MaxRecurse) {
2125 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
2126 assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
2128 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
2129 if (Constant *CRHS = dyn_cast<Constant>(RHS))
2130 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
2132 // If we have a constant, make sure it is on the RHS.
2133 std::swap(LHS, RHS);
2134 Pred = CmpInst::getSwappedPredicate(Pred);
2137 Type *ITy = GetCompareTy(LHS); // The return type.
2138 Type *OpTy = LHS->getType(); // The operand type.
2140 // icmp X, X -> true/false
2141 // X icmp undef -> true/false. For example, icmp ugt %X, undef -> false
2142 // because X could be 0.
2143 if (LHS == RHS || isa<UndefValue>(RHS))
2144 return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
2146 // Special case logic when the operands have i1 type.
2147 if (OpTy->getScalarType()->isIntegerTy(1)) {
2150 case ICmpInst::ICMP_EQ:
2152 if (match(RHS, m_One()))
2155 case ICmpInst::ICMP_NE:
2157 if (match(RHS, m_Zero()))
2160 case ICmpInst::ICMP_UGT:
2162 if (match(RHS, m_Zero()))
2165 case ICmpInst::ICMP_UGE:
2167 if (match(RHS, m_One()))
2170 case ICmpInst::ICMP_SLT:
2172 if (match(RHS, m_Zero()))
2175 case ICmpInst::ICMP_SLE:
2177 if (match(RHS, m_One()))
2183 // If we are comparing with zero then try hard since this is a common case.
2184 if (match(RHS, m_Zero())) {
2185 bool LHSKnownNonNegative, LHSKnownNegative;
2187 default: llvm_unreachable("Unknown ICmp predicate!");
2188 case ICmpInst::ICMP_ULT:
2189 return getFalse(ITy);
2190 case ICmpInst::ICMP_UGE:
2191 return getTrue(ITy);
2192 case ICmpInst::ICMP_EQ:
2193 case ICmpInst::ICMP_ULE:
2194 if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2195 return getFalse(ITy);
2197 case ICmpInst::ICMP_NE:
2198 case ICmpInst::ICMP_UGT:
2199 if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2200 return getTrue(ITy);
2202 case ICmpInst::ICMP_SLT:
2203 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL, 0, Q.AC,
2205 if (LHSKnownNegative)
2206 return getTrue(ITy);
2207 if (LHSKnownNonNegative)
2208 return getFalse(ITy);
2210 case ICmpInst::ICMP_SLE:
2211 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL, 0, Q.AC,
2213 if (LHSKnownNegative)
2214 return getTrue(ITy);
2215 if (LHSKnownNonNegative &&
2216 isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2217 return getFalse(ITy);
2219 case ICmpInst::ICMP_SGE:
2220 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL, 0, Q.AC,
2222 if (LHSKnownNegative)
2223 return getFalse(ITy);
2224 if (LHSKnownNonNegative)
2225 return getTrue(ITy);
2227 case ICmpInst::ICMP_SGT:
2228 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL, 0, Q.AC,
2230 if (LHSKnownNegative)
2231 return getFalse(ITy);
2232 if (LHSKnownNonNegative &&
2233 isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2234 return getTrue(ITy);
2239 // See if we are doing a comparison with a constant integer.
2240 if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2241 // Rule out tautological comparisons (eg., ult 0 or uge 0).
2242 ConstantRange RHS_CR = ICmpInst::makeConstantRange(Pred, CI->getValue());
2243 if (RHS_CR.isEmptySet())
2244 return ConstantInt::getFalse(CI->getContext());
2245 if (RHS_CR.isFullSet())
2246 return ConstantInt::getTrue(CI->getContext());
2248 // Many binary operators with constant RHS have easy to compute constant
2249 // range. Use them to check whether the comparison is a tautology.
2250 unsigned Width = CI->getBitWidth();
2251 APInt Lower = APInt(Width, 0);
2252 APInt Upper = APInt(Width, 0);
2254 if (match(LHS, m_URem(m_Value(), m_ConstantInt(CI2)))) {
2255 // 'urem x, CI2' produces [0, CI2).
2256 Upper = CI2->getValue();
2257 } else if (match(LHS, m_SRem(m_Value(), m_ConstantInt(CI2)))) {
2258 // 'srem x, CI2' produces (-|CI2|, |CI2|).
2259 Upper = CI2->getValue().abs();
2260 Lower = (-Upper) + 1;
2261 } else if (match(LHS, m_UDiv(m_ConstantInt(CI2), m_Value()))) {
2262 // 'udiv CI2, x' produces [0, CI2].
2263 Upper = CI2->getValue() + 1;
2264 } else if (match(LHS, m_UDiv(m_Value(), m_ConstantInt(CI2)))) {
2265 // 'udiv x, CI2' produces [0, UINT_MAX / CI2].
2266 APInt NegOne = APInt::getAllOnesValue(Width);
2268 Upper = NegOne.udiv(CI2->getValue()) + 1;
2269 } else if (match(LHS, m_SDiv(m_ConstantInt(CI2), m_Value()))) {
2270 if (CI2->isMinSignedValue()) {
2271 // 'sdiv INT_MIN, x' produces [INT_MIN, INT_MIN / -2].
2272 Lower = CI2->getValue();
2273 Upper = Lower.lshr(1) + 1;
2275 // 'sdiv CI2, x' produces [-|CI2|, |CI2|].
2276 Upper = CI2->getValue().abs() + 1;
2277 Lower = (-Upper) + 1;
2279 } else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) {
2280 APInt IntMin = APInt::getSignedMinValue(Width);
2281 APInt IntMax = APInt::getSignedMaxValue(Width);
2282 APInt Val = CI2->getValue();
2283 if (Val.isAllOnesValue()) {
2284 // 'sdiv x, -1' produces [INT_MIN + 1, INT_MAX]
2285 // where CI2 != -1 and CI2 != 0 and CI2 != 1
2288 } else if (Val.countLeadingZeros() < Width - 1) {
2289 // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2]
2290 // where CI2 != -1 and CI2 != 0 and CI2 != 1
2291 Lower = IntMin.sdiv(Val);
2292 Upper = IntMax.sdiv(Val);
2293 if (Lower.sgt(Upper))
2294 std::swap(Lower, Upper);
2296 assert(Upper != Lower && "Upper part of range has wrapped!");
2298 } else if (match(LHS, m_NUWShl(m_ConstantInt(CI2), m_Value()))) {
2299 // 'shl nuw CI2, x' produces [CI2, CI2 << CLZ(CI2)]
2300 Lower = CI2->getValue();
2301 Upper = Lower.shl(Lower.countLeadingZeros()) + 1;
2302 } else if (match(LHS, m_NSWShl(m_ConstantInt(CI2), m_Value()))) {
2303 if (CI2->isNegative()) {
2304 // 'shl nsw CI2, x' produces [CI2 << CLO(CI2)-1, CI2]
2305 unsigned ShiftAmount = CI2->getValue().countLeadingOnes() - 1;
2306 Lower = CI2->getValue().shl(ShiftAmount);
2307 Upper = CI2->getValue() + 1;
2309 // 'shl nsw CI2, x' produces [CI2, CI2 << CLZ(CI2)-1]
2310 unsigned ShiftAmount = CI2->getValue().countLeadingZeros() - 1;
2311 Lower = CI2->getValue();
2312 Upper = CI2->getValue().shl(ShiftAmount) + 1;
2314 } else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) {
2315 // 'lshr x, CI2' produces [0, UINT_MAX >> CI2].
2316 APInt NegOne = APInt::getAllOnesValue(Width);
2317 if (CI2->getValue().ult(Width))
2318 Upper = NegOne.lshr(CI2->getValue()) + 1;
2319 } else if (match(LHS, m_LShr(m_ConstantInt(CI2), m_Value()))) {
2320 // 'lshr CI2, x' produces [CI2 >> (Width-1), CI2].
2321 unsigned ShiftAmount = Width - 1;
2322 if (!CI2->isZero() && cast<BinaryOperator>(LHS)->isExact())
2323 ShiftAmount = CI2->getValue().countTrailingZeros();
2324 Lower = CI2->getValue().lshr(ShiftAmount);
2325 Upper = CI2->getValue() + 1;
2326 } else if (match(LHS, m_AShr(m_Value(), m_ConstantInt(CI2)))) {
2327 // 'ashr x, CI2' produces [INT_MIN >> CI2, INT_MAX >> CI2].
2328 APInt IntMin = APInt::getSignedMinValue(Width);
2329 APInt IntMax = APInt::getSignedMaxValue(Width);
2330 if (CI2->getValue().ult(Width)) {
2331 Lower = IntMin.ashr(CI2->getValue());
2332 Upper = IntMax.ashr(CI2->getValue()) + 1;
2334 } else if (match(LHS, m_AShr(m_ConstantInt(CI2), m_Value()))) {
2335 unsigned ShiftAmount = Width - 1;
2336 if (!CI2->isZero() && cast<BinaryOperator>(LHS)->isExact())
2337 ShiftAmount = CI2->getValue().countTrailingZeros();
2338 if (CI2->isNegative()) {
2339 // 'ashr CI2, x' produces [CI2, CI2 >> (Width-1)]
2340 Lower = CI2->getValue();
2341 Upper = CI2->getValue().ashr(ShiftAmount) + 1;
2343 // 'ashr CI2, x' produces [CI2 >> (Width-1), CI2]
2344 Lower = CI2->getValue().ashr(ShiftAmount);
2345 Upper = CI2->getValue() + 1;
2347 } else if (match(LHS, m_Or(m_Value(), m_ConstantInt(CI2)))) {
2348 // 'or x, CI2' produces [CI2, UINT_MAX].
2349 Lower = CI2->getValue();
2350 } else if (match(LHS, m_And(m_Value(), m_ConstantInt(CI2)))) {
2351 // 'and x, CI2' produces [0, CI2].
2352 Upper = CI2->getValue() + 1;
2354 if (Lower != Upper) {
2355 ConstantRange LHS_CR = ConstantRange(Lower, Upper);
2356 if (RHS_CR.contains(LHS_CR))
2357 return ConstantInt::getTrue(RHS->getContext());
2358 if (RHS_CR.inverse().contains(LHS_CR))
2359 return ConstantInt::getFalse(RHS->getContext());
2363 // Compare of cast, for example (zext X) != 0 -> X != 0
2364 if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
2365 Instruction *LI = cast<CastInst>(LHS);
2366 Value *SrcOp = LI->getOperand(0);
2367 Type *SrcTy = SrcOp->getType();
2368 Type *DstTy = LI->getType();
2370 // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
2371 // if the integer type is the same size as the pointer type.
2372 if (MaxRecurse && Q.DL && isa<PtrToIntInst>(LI) &&
2373 Q.DL->getTypeSizeInBits(SrcTy) == DstTy->getPrimitiveSizeInBits()) {
2374 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
2375 // Transfer the cast to the constant.
2376 if (Value *V = SimplifyICmpInst(Pred, SrcOp,
2377 ConstantExpr::getIntToPtr(RHSC, SrcTy),
2380 } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
2381 if (RI->getOperand(0)->getType() == SrcTy)
2382 // Compare without the cast.
2383 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2389 if (isa<ZExtInst>(LHS)) {
2390 // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
2392 if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
2393 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2394 // Compare X and Y. Note that signed predicates become unsigned.
2395 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
2396 SrcOp, RI->getOperand(0), Q,
2400 // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
2401 // too. If not, then try to deduce the result of the comparison.
2402 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2403 // Compute the constant that would happen if we truncated to SrcTy then
2404 // reextended to DstTy.
2405 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2406 Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
2408 // If the re-extended constant didn't change then this is effectively
2409 // also a case of comparing two zero-extended values.
2410 if (RExt == CI && MaxRecurse)
2411 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
2412 SrcOp, Trunc, Q, MaxRecurse-1))
2415 // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
2416 // there. Use this to work out the result of the comparison.
2419 default: llvm_unreachable("Unknown ICmp predicate!");
2421 case ICmpInst::ICMP_EQ:
2422 case ICmpInst::ICMP_UGT:
2423 case ICmpInst::ICMP_UGE:
2424 return ConstantInt::getFalse(CI->getContext());
2426 case ICmpInst::ICMP_NE:
2427 case ICmpInst::ICMP_ULT:
2428 case ICmpInst::ICMP_ULE:
2429 return ConstantInt::getTrue(CI->getContext());
2431 // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
2432 // is non-negative then LHS <s RHS.
2433 case ICmpInst::ICMP_SGT:
2434 case ICmpInst::ICMP_SGE:
2435 return CI->getValue().isNegative() ?
2436 ConstantInt::getTrue(CI->getContext()) :
2437 ConstantInt::getFalse(CI->getContext());
2439 case ICmpInst::ICMP_SLT:
2440 case ICmpInst::ICMP_SLE:
2441 return CI->getValue().isNegative() ?
2442 ConstantInt::getFalse(CI->getContext()) :
2443 ConstantInt::getTrue(CI->getContext());
2449 if (isa<SExtInst>(LHS)) {
2450 // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
2452 if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
2453 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2454 // Compare X and Y. Note that the predicate does not change.
2455 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2459 // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
2460 // too. If not, then try to deduce the result of the comparison.
2461 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2462 // Compute the constant that would happen if we truncated to SrcTy then
2463 // reextended to DstTy.
2464 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2465 Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
2467 // If the re-extended constant didn't change then this is effectively
2468 // also a case of comparing two sign-extended values.
2469 if (RExt == CI && MaxRecurse)
2470 if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
2473 // Otherwise the upper bits of LHS are all equal, while RHS has varying
2474 // bits there. Use this to work out the result of the comparison.
2477 default: llvm_unreachable("Unknown ICmp predicate!");
2478 case ICmpInst::ICMP_EQ:
2479 return ConstantInt::getFalse(CI->getContext());
2480 case ICmpInst::ICMP_NE:
2481 return ConstantInt::getTrue(CI->getContext());
2483 // If RHS is non-negative then LHS <s RHS. If RHS is negative then
2485 case ICmpInst::ICMP_SGT:
2486 case ICmpInst::ICMP_SGE:
2487 return CI->getValue().isNegative() ?
2488 ConstantInt::getTrue(CI->getContext()) :
2489 ConstantInt::getFalse(CI->getContext());
2490 case ICmpInst::ICMP_SLT:
2491 case ICmpInst::ICMP_SLE:
2492 return CI->getValue().isNegative() ?
2493 ConstantInt::getFalse(CI->getContext()) :
2494 ConstantInt::getTrue(CI->getContext());
2496 // If LHS is non-negative then LHS <u RHS. If LHS is negative then
2498 case ICmpInst::ICMP_UGT:
2499 case ICmpInst::ICMP_UGE:
2500 // Comparison is true iff the LHS <s 0.
2502 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
2503 Constant::getNullValue(SrcTy),
2507 case ICmpInst::ICMP_ULT:
2508 case ICmpInst::ICMP_ULE:
2509 // Comparison is true iff the LHS >=s 0.
2511 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
2512 Constant::getNullValue(SrcTy),
2522 // Special logic for binary operators.
2523 BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
2524 BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
2525 if (MaxRecurse && (LBO || RBO)) {
2526 // Analyze the case when either LHS or RHS is an add instruction.
2527 Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
2528 // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
2529 bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
2530 if (LBO && LBO->getOpcode() == Instruction::Add) {
2531 A = LBO->getOperand(0); B = LBO->getOperand(1);
2532 NoLHSWrapProblem = ICmpInst::isEquality(Pred) ||
2533 (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
2534 (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
2536 if (RBO && RBO->getOpcode() == Instruction::Add) {
2537 C = RBO->getOperand(0); D = RBO->getOperand(1);
2538 NoRHSWrapProblem = ICmpInst::isEquality(Pred) ||
2539 (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
2540 (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
2543 // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
2544 if ((A == RHS || B == RHS) && NoLHSWrapProblem)
2545 if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
2546 Constant::getNullValue(RHS->getType()),
2550 // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
2551 if ((C == LHS || D == LHS) && NoRHSWrapProblem)
2552 if (Value *V = SimplifyICmpInst(Pred,
2553 Constant::getNullValue(LHS->getType()),
2554 C == LHS ? D : C, Q, MaxRecurse-1))
2557 // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
2558 if (A && C && (A == C || A == D || B == C || B == D) &&
2559 NoLHSWrapProblem && NoRHSWrapProblem) {
2560 // Determine Y and Z in the form icmp (X+Y), (X+Z).
2563 // C + B == C + D -> B == D
2566 } else if (A == D) {
2567 // D + B == C + D -> B == C
2570 } else if (B == C) {
2571 // A + C == C + D -> A == D
2576 // A + D == C + D -> A == C
2580 if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse-1))
2585 // icmp pred (or X, Y), X
2586 if (LBO && match(LBO, m_CombineOr(m_Or(m_Value(), m_Specific(RHS)),
2587 m_Or(m_Specific(RHS), m_Value())))) {
2588 if (Pred == ICmpInst::ICMP_ULT)
2589 return getFalse(ITy);
2590 if (Pred == ICmpInst::ICMP_UGE)
2591 return getTrue(ITy);
2593 // icmp pred X, (or X, Y)
2594 if (RBO && match(RBO, m_CombineOr(m_Or(m_Value(), m_Specific(LHS)),
2595 m_Or(m_Specific(LHS), m_Value())))) {
2596 if (Pred == ICmpInst::ICMP_ULE)
2597 return getTrue(ITy);
2598 if (Pred == ICmpInst::ICMP_UGT)
2599 return getFalse(ITy);
2602 // icmp pred (and X, Y), X
2603 if (LBO && match(LBO, m_CombineOr(m_And(m_Value(), m_Specific(RHS)),
2604 m_And(m_Specific(RHS), m_Value())))) {
2605 if (Pred == ICmpInst::ICMP_UGT)
2606 return getFalse(ITy);
2607 if (Pred == ICmpInst::ICMP_ULE)
2608 return getTrue(ITy);
2610 // icmp pred X, (and X, Y)
2611 if (RBO && match(RBO, m_CombineOr(m_And(m_Value(), m_Specific(LHS)),
2612 m_And(m_Specific(LHS), m_Value())))) {
2613 if (Pred == ICmpInst::ICMP_UGE)
2614 return getTrue(ITy);
2615 if (Pred == ICmpInst::ICMP_ULT)
2616 return getFalse(ITy);
2619 // 0 - (zext X) pred C
2620 if (!CmpInst::isUnsigned(Pred) && match(LHS, m_Neg(m_ZExt(m_Value())))) {
2621 if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS)) {
2622 if (RHSC->getValue().isStrictlyPositive()) {
2623 if (Pred == ICmpInst::ICMP_SLT)
2624 return ConstantInt::getTrue(RHSC->getContext());
2625 if (Pred == ICmpInst::ICMP_SGE)
2626 return ConstantInt::getFalse(RHSC->getContext());
2627 if (Pred == ICmpInst::ICMP_EQ)
2628 return ConstantInt::getFalse(RHSC->getContext());
2629 if (Pred == ICmpInst::ICMP_NE)
2630 return ConstantInt::getTrue(RHSC->getContext());
2632 if (RHSC->getValue().isNonNegative()) {
2633 if (Pred == ICmpInst::ICMP_SLE)
2634 return ConstantInt::getTrue(RHSC->getContext());
2635 if (Pred == ICmpInst::ICMP_SGT)
2636 return ConstantInt::getFalse(RHSC->getContext());
2641 // icmp pred (urem X, Y), Y
2642 if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
2643 bool KnownNonNegative, KnownNegative;
2647 case ICmpInst::ICMP_SGT:
2648 case ICmpInst::ICMP_SGE:
2649 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.DL, 0, Q.AC,
2651 if (!KnownNonNegative)
2654 case ICmpInst::ICMP_EQ:
2655 case ICmpInst::ICMP_UGT:
2656 case ICmpInst::ICMP_UGE:
2657 return getFalse(ITy);
2658 case ICmpInst::ICMP_SLT:
2659 case ICmpInst::ICMP_SLE:
2660 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.DL, 0, Q.AC,
2662 if (!KnownNonNegative)
2665 case ICmpInst::ICMP_NE:
2666 case ICmpInst::ICMP_ULT:
2667 case ICmpInst::ICMP_ULE:
2668 return getTrue(ITy);
2672 // icmp pred X, (urem Y, X)
2673 if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
2674 bool KnownNonNegative, KnownNegative;
2678 case ICmpInst::ICMP_SGT:
2679 case ICmpInst::ICMP_SGE:
2680 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.DL, 0, Q.AC,
2682 if (!KnownNonNegative)
2685 case ICmpInst::ICMP_NE:
2686 case ICmpInst::ICMP_UGT:
2687 case ICmpInst::ICMP_UGE:
2688 return getTrue(ITy);
2689 case ICmpInst::ICMP_SLT:
2690 case ICmpInst::ICMP_SLE:
2691 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.DL, 0, Q.AC,
2693 if (!KnownNonNegative)
2696 case ICmpInst::ICMP_EQ:
2697 case ICmpInst::ICMP_ULT:
2698 case ICmpInst::ICMP_ULE:
2699 return getFalse(ITy);
2704 if (LBO && match(LBO, m_UDiv(m_Specific(RHS), m_Value()))) {
2705 // icmp pred (X /u Y), X
2706 if (Pred == ICmpInst::ICMP_UGT)
2707 return getFalse(ITy);
2708 if (Pred == ICmpInst::ICMP_ULE)
2709 return getTrue(ITy);
2716 // where CI2 is a power of 2 and CI isn't
2717 if (auto *CI = dyn_cast<ConstantInt>(RHS)) {
2718 const APInt *CI2Val, *CIVal = &CI->getValue();
2719 if (LBO && match(LBO, m_Shl(m_APInt(CI2Val), m_Value())) &&
2720 CI2Val->isPowerOf2()) {
2721 if (!CIVal->isPowerOf2()) {
2722 // CI2 << X can equal zero in some circumstances,
2723 // this simplification is unsafe if CI is zero.
2725 // We know it is safe if:
2726 // - The shift is nsw, we can't shift out the one bit.
2727 // - The shift is nuw, we can't shift out the one bit.
2730 if (LBO->hasNoSignedWrap() || LBO->hasNoUnsignedWrap() ||
2731 *CI2Val == 1 || !CI->isZero()) {
2732 if (Pred == ICmpInst::ICMP_EQ)
2733 return ConstantInt::getFalse(RHS->getContext());
2734 if (Pred == ICmpInst::ICMP_NE)
2735 return ConstantInt::getTrue(RHS->getContext());
2738 if (CIVal->isSignBit() && *CI2Val == 1) {
2739 if (Pred == ICmpInst::ICMP_UGT)
2740 return ConstantInt::getFalse(RHS->getContext());
2741 if (Pred == ICmpInst::ICMP_ULE)
2742 return ConstantInt::getTrue(RHS->getContext());
2747 if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
2748 LBO->getOperand(1) == RBO->getOperand(1)) {
2749 switch (LBO->getOpcode()) {
2751 case Instruction::UDiv:
2752 case Instruction::LShr:
2753 if (ICmpInst::isSigned(Pred))
2756 case Instruction::SDiv:
2757 case Instruction::AShr:
2758 if (!LBO->isExact() || !RBO->isExact())
2760 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2761 RBO->getOperand(0), Q, MaxRecurse-1))
2764 case Instruction::Shl: {
2765 bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
2766 bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
2769 if (!NSW && ICmpInst::isSigned(Pred))
2771 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2772 RBO->getOperand(0), Q, MaxRecurse-1))
2779 // Simplify comparisons involving max/min.
2781 CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE;
2782 CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
2784 // Signed variants on "max(a,b)>=a -> true".
2785 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2786 if (A != RHS) std::swap(A, B); // smax(A, B) pred A.
2787 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2788 // We analyze this as smax(A, B) pred A.
2790 } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
2791 (A == LHS || B == LHS)) {
2792 if (A != LHS) std::swap(A, B); // A pred smax(A, B).
2793 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2794 // We analyze this as smax(A, B) swapped-pred A.
2795 P = CmpInst::getSwappedPredicate(Pred);
2796 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2797 (A == RHS || B == RHS)) {
2798 if (A != RHS) std::swap(A, B); // smin(A, B) pred A.
2799 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2800 // We analyze this as smax(-A, -B) swapped-pred -A.
2801 // Note that we do not need to actually form -A or -B thanks to EqP.
2802 P = CmpInst::getSwappedPredicate(Pred);
2803 } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
2804 (A == LHS || B == LHS)) {
2805 if (A != LHS) std::swap(A, B); // A pred smin(A, B).
2806 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2807 // We analyze this as smax(-A, -B) pred -A.
2808 // Note that we do not need to actually form -A or -B thanks to EqP.
2811 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2812 // Cases correspond to "max(A, B) p A".
2816 case CmpInst::ICMP_EQ:
2817 case CmpInst::ICMP_SLE:
2818 // Equivalent to "A EqP B". This may be the same as the condition tested
2819 // in the max/min; if so, we can just return that.
2820 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2822 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2824 // Otherwise, see if "A EqP B" simplifies.
2826 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2829 case CmpInst::ICMP_NE:
2830 case CmpInst::ICMP_SGT: {
2831 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2832 // Equivalent to "A InvEqP B". This may be the same as the condition
2833 // tested in the max/min; if so, we can just return that.
2834 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2836 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2838 // Otherwise, see if "A InvEqP B" simplifies.
2840 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2844 case CmpInst::ICMP_SGE:
2846 return getTrue(ITy);
2847 case CmpInst::ICMP_SLT:
2849 return getFalse(ITy);
2853 // Unsigned variants on "max(a,b)>=a -> true".
2854 P = CmpInst::BAD_ICMP_PREDICATE;
2855 if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2856 if (A != RHS) std::swap(A, B); // umax(A, B) pred A.
2857 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2858 // We analyze this as umax(A, B) pred A.
2860 } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
2861 (A == LHS || B == LHS)) {
2862 if (A != LHS) std::swap(A, B); // A pred umax(A, B).
2863 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2864 // We analyze this as umax(A, B) swapped-pred A.
2865 P = CmpInst::getSwappedPredicate(Pred);
2866 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2867 (A == RHS || B == RHS)) {
2868 if (A != RHS) std::swap(A, B); // umin(A, B) pred A.
2869 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2870 // We analyze this as umax(-A, -B) swapped-pred -A.
2871 // Note that we do not need to actually form -A or -B thanks to EqP.
2872 P = CmpInst::getSwappedPredicate(Pred);
2873 } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
2874 (A == LHS || B == LHS)) {
2875 if (A != LHS) std::swap(A, B); // A pred umin(A, B).
2876 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2877 // We analyze this as umax(-A, -B) pred -A.
2878 // Note that we do not need to actually form -A or -B thanks to EqP.
2881 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2882 // Cases correspond to "max(A, B) p A".
2886 case CmpInst::ICMP_EQ:
2887 case CmpInst::ICMP_ULE:
2888 // Equivalent to "A EqP B". This may be the same as the condition tested
2889 // in the max/min; if so, we can just return that.
2890 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2892 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2894 // Otherwise, see if "A EqP B" simplifies.
2896 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2899 case CmpInst::ICMP_NE:
2900 case CmpInst::ICMP_UGT: {
2901 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2902 // Equivalent to "A InvEqP B". This may be the same as the condition
2903 // tested in the max/min; if so, we can just return that.
2904 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2906 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2908 // Otherwise, see if "A InvEqP B" simplifies.
2910 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2914 case CmpInst::ICMP_UGE:
2916 return getTrue(ITy);
2917 case CmpInst::ICMP_ULT:
2919 return getFalse(ITy);
2923 // Variants on "max(x,y) >= min(x,z)".
2925 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
2926 match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
2927 (A == C || A == D || B == C || B == D)) {
2928 // max(x, ?) pred min(x, ?).
2929 if (Pred == CmpInst::ICMP_SGE)
2931 return getTrue(ITy);
2932 if (Pred == CmpInst::ICMP_SLT)
2934 return getFalse(ITy);
2935 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2936 match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
2937 (A == C || A == D || B == C || B == D)) {
2938 // min(x, ?) pred max(x, ?).
2939 if (Pred == CmpInst::ICMP_SLE)
2941 return getTrue(ITy);
2942 if (Pred == CmpInst::ICMP_SGT)
2944 return getFalse(ITy);
2945 } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
2946 match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
2947 (A == C || A == D || B == C || B == D)) {
2948 // max(x, ?) pred min(x, ?).
2949 if (Pred == CmpInst::ICMP_UGE)
2951 return getTrue(ITy);
2952 if (Pred == CmpInst::ICMP_ULT)
2954 return getFalse(ITy);
2955 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2956 match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
2957 (A == C || A == D || B == C || B == D)) {
2958 // min(x, ?) pred max(x, ?).
2959 if (Pred == CmpInst::ICMP_ULE)
2961 return getTrue(ITy);
2962 if (Pred == CmpInst::ICMP_UGT)
2964 return getFalse(ITy);
2967 // Simplify comparisons of related pointers using a powerful, recursive
2968 // GEP-walk when we have target data available..
2969 if (LHS->getType()->isPointerTy())
2970 if (Constant *C = computePointerICmp(Q.DL, Q.TLI, Pred, LHS, RHS))
2973 if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
2974 if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
2975 if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
2976 GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
2977 (ICmpInst::isEquality(Pred) ||
2978 (GLHS->isInBounds() && GRHS->isInBounds() &&
2979 Pred == ICmpInst::getSignedPredicate(Pred)))) {
2980 // The bases are equal and the indices are constant. Build a constant
2981 // expression GEP with the same indices and a null base pointer to see
2982 // what constant folding can make out of it.
2983 Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
2984 SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
2985 Constant *NewLHS = ConstantExpr::getGetElementPtr(Null, IndicesLHS);
2987 SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
2988 Constant *NewRHS = ConstantExpr::getGetElementPtr(Null, IndicesRHS);
2989 return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
2994 // If a bit is known to be zero for A and known to be one for B,
2995 // then A and B cannot be equal.
2996 if (ICmpInst::isEquality(Pred)) {
2997 if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2998 uint32_t BitWidth = CI->getBitWidth();
2999 APInt LHSKnownZero(BitWidth, 0);
3000 APInt LHSKnownOne(BitWidth, 0);
3001 computeKnownBits(LHS, LHSKnownZero, LHSKnownOne, Q.DL, /*Depth=*/0, Q.AC,
3003 const APInt &RHSVal = CI->getValue();
3004 if (((LHSKnownZero & RHSVal) != 0) || ((LHSKnownOne & ~RHSVal) != 0))
3005 return Pred == ICmpInst::ICMP_EQ
3006 ? ConstantInt::getFalse(CI->getContext())
3007 : ConstantInt::getTrue(CI->getContext());
3011 // If the comparison is with the result of a select instruction, check whether
3012 // comparing with either branch of the select always yields the same value.
3013 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3014 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
3017 // If the comparison is with the result of a phi instruction, check whether
3018 // doing the compare with each incoming phi value yields a common result.
3019 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3020 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
3026 Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3027 const DataLayout *DL,
3028 const TargetLibraryInfo *TLI,
3029 const DominatorTree *DT, AssumptionCache *AC,
3030 Instruction *CxtI) {
3031 return ::SimplifyICmpInst(Predicate, LHS, RHS, Query(DL, TLI, DT, AC, CxtI),
3035 /// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can
3036 /// fold the result. If not, this returns null.
3037 static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3038 const Query &Q, unsigned MaxRecurse) {
3039 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
3040 assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
3042 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
3043 if (Constant *CRHS = dyn_cast<Constant>(RHS))
3044 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
3046 // If we have a constant, make sure it is on the RHS.
3047 std::swap(LHS, RHS);
3048 Pred = CmpInst::getSwappedPredicate(Pred);
3051 // Fold trivial predicates.
3052 if (Pred == FCmpInst::FCMP_FALSE)
3053 return ConstantInt::get(GetCompareTy(LHS), 0);
3054 if (Pred == FCmpInst::FCMP_TRUE)
3055 return ConstantInt::get(GetCompareTy(LHS), 1);
3057 if (isa<UndefValue>(RHS)) // fcmp pred X, undef -> undef
3058 return UndefValue::get(GetCompareTy(LHS));
3060 // fcmp x,x -> true/false. Not all compares are foldable.
3062 if (CmpInst::isTrueWhenEqual(Pred))
3063 return ConstantInt::get(GetCompareTy(LHS), 1);
3064 if (CmpInst::isFalseWhenEqual(Pred))
3065 return ConstantInt::get(GetCompareTy(LHS), 0);
3068 // Handle fcmp with constant RHS
3069 if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHS)) {
3070 // If the constant is a nan, see if we can fold the comparison based on it.
3071 if (CFP->getValueAPF().isNaN()) {
3072 if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo"
3073 return ConstantInt::getFalse(CFP->getContext());
3074 assert(FCmpInst::isUnordered(Pred) &&
3075 "Comparison must be either ordered or unordered!");
3076 // True if unordered.
3077 return ConstantInt::getTrue(CFP->getContext());
3079 // Check whether the constant is an infinity.
3080 if (CFP->getValueAPF().isInfinity()) {
3081 if (CFP->getValueAPF().isNegative()) {
3083 case FCmpInst::FCMP_OLT:
3084 // No value is ordered and less than negative infinity.
3085 return ConstantInt::getFalse(CFP->getContext());
3086 case FCmpInst::FCMP_UGE:
3087 // All values are unordered with or at least negative infinity.
3088 return ConstantInt::getTrue(CFP->getContext());
3094 case FCmpInst::FCMP_OGT:
3095 // No value is ordered and greater than infinity.
3096 return ConstantInt::getFalse(CFP->getContext());
3097 case FCmpInst::FCMP_ULE:
3098 // All values are unordered with and at most infinity.
3099 return ConstantInt::getTrue(CFP->getContext());
3105 if (CFP->getValueAPF().isZero()) {
3107 case FCmpInst::FCMP_UGE:
3108 if (CannotBeOrderedLessThanZero(LHS))
3109 return ConstantInt::getTrue(CFP->getContext());
3111 case FCmpInst::FCMP_OLT:
3113 if (CannotBeOrderedLessThanZero(LHS))
3114 return ConstantInt::getFalse(CFP->getContext());
3122 // If the comparison is with the result of a select instruction, check whether
3123 // comparing with either branch of the select always yields the same value.
3124 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3125 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
3128 // If the comparison is with the result of a phi instruction, check whether
3129 // doing the compare with each incoming phi value yields a common result.
3130 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3131 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
3137 Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3138 const DataLayout *DL,
3139 const TargetLibraryInfo *TLI,
3140 const DominatorTree *DT, AssumptionCache *AC,
3141 const Instruction *CxtI) {
3142 return ::SimplifyFCmpInst(Predicate, LHS, RHS, Query(DL, TLI, DT, AC, CxtI),
3146 /// SimplifySelectInst - Given operands for a SelectInst, see if we can fold
3147 /// the result. If not, this returns null.
3148 static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal,
3149 Value *FalseVal, const Query &Q,
3150 unsigned MaxRecurse) {
3151 // select true, X, Y -> X
3152 // select false, X, Y -> Y
3153 if (Constant *CB = dyn_cast<Constant>(CondVal)) {
3154 if (CB->isAllOnesValue())
3156 if (CB->isNullValue())
3160 // select C, X, X -> X
3161 if (TrueVal == FalseVal)
3164 if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y
3165 if (isa<Constant>(TrueVal))
3169 if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X
3171 if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
3174 const auto *ICI = dyn_cast<ICmpInst>(CondVal);
3175 unsigned BitWidth = TrueVal->getType()->getScalarSizeInBits();
3176 if (ICI && BitWidth) {
3177 ICmpInst::Predicate Pred = ICI->getPredicate();
3178 APInt MinSignedValue = APInt::getSignBit(BitWidth);
3182 bool IsBitTest = false;
3183 if (ICmpInst::isEquality(Pred) &&
3184 match(ICI->getOperand(0), m_And(m_Value(X), m_APInt(Y))) &&
3185 match(ICI->getOperand(1), m_Zero())) {
3187 TrueWhenUnset = Pred == ICmpInst::ICMP_EQ;
3188 } else if (Pred == ICmpInst::ICMP_SLT &&
3189 match(ICI->getOperand(1), m_Zero())) {
3190 X = ICI->getOperand(0);
3191 Y = &MinSignedValue;
3193 TrueWhenUnset = false;
3194 } else if (Pred == ICmpInst::ICMP_SGT &&
3195 match(ICI->getOperand(1), m_AllOnes())) {
3196 X = ICI->getOperand(0);
3197 Y = &MinSignedValue;
3199 TrueWhenUnset = true;
3203 // (X & Y) == 0 ? X & ~Y : X --> X
3204 // (X & Y) != 0 ? X & ~Y : X --> X & ~Y
3205 if (FalseVal == X && match(TrueVal, m_And(m_Specific(X), m_APInt(C))) &&
3207 return TrueWhenUnset ? FalseVal : TrueVal;
3208 // (X & Y) == 0 ? X : X & ~Y --> X & ~Y
3209 // (X & Y) != 0 ? X : X & ~Y --> X
3210 if (TrueVal == X && match(FalseVal, m_And(m_Specific(X), m_APInt(C))) &&
3212 return TrueWhenUnset ? FalseVal : TrueVal;
3214 if (Y->isPowerOf2()) {
3215 // (X & Y) == 0 ? X | Y : X --> X | Y
3216 // (X & Y) != 0 ? X | Y : X --> X
3217 if (FalseVal == X && match(TrueVal, m_Or(m_Specific(X), m_APInt(C))) &&
3219 return TrueWhenUnset ? TrueVal : FalseVal;
3220 // (X & Y) == 0 ? X : X | Y --> X
3221 // (X & Y) != 0 ? X : X | Y --> X | Y
3222 if (TrueVal == X && match(FalseVal, m_Or(m_Specific(X), m_APInt(C))) &&
3224 return TrueWhenUnset ? TrueVal : FalseVal;
3232 Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
3233 const DataLayout *DL,
3234 const TargetLibraryInfo *TLI,
3235 const DominatorTree *DT, AssumptionCache *AC,
3236 const Instruction *CxtI) {
3237 return ::SimplifySelectInst(Cond, TrueVal, FalseVal,
3238 Query(DL, TLI, DT, AC, CxtI), RecursionLimit);
3241 /// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
3242 /// fold the result. If not, this returns null.
3243 static Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const Query &Q, unsigned) {
3244 // The type of the GEP pointer operand.
3245 PointerType *PtrTy = cast<PointerType>(Ops[0]->getType()->getScalarType());
3246 unsigned AS = PtrTy->getAddressSpace();
3248 // getelementptr P -> P.
3249 if (Ops.size() == 1)
3252 // Compute the (pointer) type returned by the GEP instruction.
3253 Type *LastType = GetElementPtrInst::getIndexedType(PtrTy, Ops.slice(1));
3254 Type *GEPTy = PointerType::get(LastType, AS);
3255 if (VectorType *VT = dyn_cast<VectorType>(Ops[0]->getType()))
3256 GEPTy = VectorType::get(GEPTy, VT->getNumElements());
3258 if (isa<UndefValue>(Ops[0]))
3259 return UndefValue::get(GEPTy);
3261 if (Ops.size() == 2) {
3262 // getelementptr P, 0 -> P.
3263 if (match(Ops[1], m_Zero()))
3266 Type *Ty = PtrTy->getElementType();
3267 if (Q.DL && Ty->isSized()) {
3270 uint64_t TyAllocSize = Q.DL->getTypeAllocSize(Ty);
3271 // getelementptr P, N -> P if P points to a type of zero size.
3272 if (TyAllocSize == 0)
3275 // The following transforms are only safe if the ptrtoint cast
3276 // doesn't truncate the pointers.
3277 if (Ops[1]->getType()->getScalarSizeInBits() ==
3278 Q.DL->getPointerSizeInBits(AS)) {
3279 auto PtrToIntOrZero = [GEPTy](Value *P) -> Value * {
3280 if (match(P, m_Zero()))
3281 return Constant::getNullValue(GEPTy);
3283 if (match(P, m_PtrToInt(m_Value(Temp))))
3284 if (Temp->getType() == GEPTy)
3289 // getelementptr V, (sub P, V) -> P if P points to a type of size 1.
3290 if (TyAllocSize == 1 &&
3291 match(Ops[1], m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0])))))
3292 if (Value *R = PtrToIntOrZero(P))
3295 // getelementptr V, (ashr (sub P, V), C) -> Q
3296 // if P points to a type of size 1 << C.
3298 m_AShr(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3299 m_ConstantInt(C))) &&
3300 TyAllocSize == 1ULL << C)
3301 if (Value *R = PtrToIntOrZero(P))
3304 // getelementptr V, (sdiv (sub P, V), C) -> Q
3305 // if P points to a type of size C.
3307 m_SDiv(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3308 m_SpecificInt(TyAllocSize))))
3309 if (Value *R = PtrToIntOrZero(P))
3315 // Check to see if this is constant foldable.
3316 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
3317 if (!isa<Constant>(Ops[i]))
3320 return ConstantExpr::getGetElementPtr(cast<Constant>(Ops[0]), Ops.slice(1));
3323 Value *llvm::SimplifyGEPInst(ArrayRef<Value *> Ops, const DataLayout *DL,
3324 const TargetLibraryInfo *TLI,
3325 const DominatorTree *DT, AssumptionCache *AC,
3326 const Instruction *CxtI) {
3327 return ::SimplifyGEPInst(Ops, Query(DL, TLI, DT, AC, CxtI), RecursionLimit);
3330 /// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we
3331 /// can fold the result. If not, this returns null.
3332 static Value *SimplifyInsertValueInst(Value *Agg, Value *Val,
3333 ArrayRef<unsigned> Idxs, const Query &Q,
3335 if (Constant *CAgg = dyn_cast<Constant>(Agg))
3336 if (Constant *CVal = dyn_cast<Constant>(Val))
3337 return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
3339 // insertvalue x, undef, n -> x
3340 if (match(Val, m_Undef()))
3343 // insertvalue x, (extractvalue y, n), n
3344 if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
3345 if (EV->getAggregateOperand()->getType() == Agg->getType() &&
3346 EV->getIndices() == Idxs) {
3347 // insertvalue undef, (extractvalue y, n), n -> y
3348 if (match(Agg, m_Undef()))
3349 return EV->getAggregateOperand();
3351 // insertvalue y, (extractvalue y, n), n -> y
3352 if (Agg == EV->getAggregateOperand())
3359 Value *llvm::SimplifyInsertValueInst(
3360 Value *Agg, Value *Val, ArrayRef<unsigned> Idxs, const DataLayout *DL,
3361 const TargetLibraryInfo *TLI, const DominatorTree *DT, AssumptionCache *AC,
3362 const Instruction *CxtI) {
3363 return ::SimplifyInsertValueInst(Agg, Val, Idxs, Query(DL, TLI, DT, AC, CxtI),
3367 /// SimplifyPHINode - See if we can fold the given phi. If not, returns null.
3368 static Value *SimplifyPHINode(PHINode *PN, const Query &Q) {
3369 // If all of the PHI's incoming values are the same then replace the PHI node
3370 // with the common value.
3371 Value *CommonValue = nullptr;
3372 bool HasUndefInput = false;
3373 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
3374 Value *Incoming = PN->getIncomingValue(i);
3375 // If the incoming value is the phi node itself, it can safely be skipped.
3376 if (Incoming == PN) continue;
3377 if (isa<UndefValue>(Incoming)) {
3378 // Remember that we saw an undef value, but otherwise ignore them.
3379 HasUndefInput = true;
3382 if (CommonValue && Incoming != CommonValue)
3383 return nullptr; // Not the same, bail out.
3384 CommonValue = Incoming;
3387 // If CommonValue is null then all of the incoming values were either undef or
3388 // equal to the phi node itself.
3390 return UndefValue::get(PN->getType());
3392 // If we have a PHI node like phi(X, undef, X), where X is defined by some
3393 // instruction, we cannot return X as the result of the PHI node unless it
3394 // dominates the PHI block.
3396 return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : nullptr;
3401 static Value *SimplifyTruncInst(Value *Op, Type *Ty, const Query &Q, unsigned) {
3402 if (Constant *C = dyn_cast<Constant>(Op))
3403 return ConstantFoldInstOperands(Instruction::Trunc, Ty, C, Q.DL, Q.TLI);
3408 Value *llvm::SimplifyTruncInst(Value *Op, Type *Ty, const DataLayout *DL,
3409 const TargetLibraryInfo *TLI,
3410 const DominatorTree *DT, AssumptionCache *AC,
3411 const Instruction *CxtI) {
3412 return ::SimplifyTruncInst(Op, Ty, Query(DL, TLI, DT, AC, CxtI),
3416 //=== Helper functions for higher up the class hierarchy.
3418 /// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
3419 /// fold the result. If not, this returns null.
3420 static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
3421 const Query &Q, unsigned MaxRecurse) {
3423 case Instruction::Add:
3424 return SimplifyAddInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
3426 case Instruction::FAdd:
3427 return SimplifyFAddInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3429 case Instruction::Sub:
3430 return SimplifySubInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
3432 case Instruction::FSub:
3433 return SimplifyFSubInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3435 case Instruction::Mul: return SimplifyMulInst (LHS, RHS, Q, MaxRecurse);
3436 case Instruction::FMul:
3437 return SimplifyFMulInst (LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3438 case Instruction::SDiv: return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
3439 case Instruction::UDiv: return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
3440 case Instruction::FDiv:
3441 return SimplifyFDivInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3442 case Instruction::SRem: return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
3443 case Instruction::URem: return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
3444 case Instruction::FRem:
3445 return SimplifyFRemInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3446 case Instruction::Shl:
3447 return SimplifyShlInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
3449 case Instruction::LShr:
3450 return SimplifyLShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
3451 case Instruction::AShr:
3452 return SimplifyAShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
3453 case Instruction::And: return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
3454 case Instruction::Or: return SimplifyOrInst (LHS, RHS, Q, MaxRecurse);
3455 case Instruction::Xor: return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
3457 if (Constant *CLHS = dyn_cast<Constant>(LHS))
3458 if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
3459 Constant *COps[] = {CLHS, CRHS};
3460 return ConstantFoldInstOperands(Opcode, LHS->getType(), COps, Q.DL,
3464 // If the operation is associative, try some generic simplifications.
3465 if (Instruction::isAssociative(Opcode))
3466 if (Value *V = SimplifyAssociativeBinOp(Opcode, LHS, RHS, Q, MaxRecurse))
3469 // If the operation is with the result of a select instruction check whether
3470 // operating on either branch of the select always yields the same value.
3471 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3472 if (Value *V = ThreadBinOpOverSelect(Opcode, LHS, RHS, Q, MaxRecurse))
3475 // If the operation is with the result of a phi instruction, check whether
3476 // operating on all incoming values of the phi always yields the same value.
3477 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3478 if (Value *V = ThreadBinOpOverPHI(Opcode, LHS, RHS, Q, MaxRecurse))
3485 /// SimplifyFPBinOp - Given operands for a BinaryOperator, see if we can
3486 /// fold the result. If not, this returns null.
3487 /// In contrast to SimplifyBinOp, try to use FastMathFlag when folding the
3488 /// result. In case we don't need FastMathFlags, simply fall to SimplifyBinOp.
3489 static Value *SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
3490 const FastMathFlags &FMF, const Query &Q,
3491 unsigned MaxRecurse) {
3493 case Instruction::FAdd:
3494 return SimplifyFAddInst(LHS, RHS, FMF, Q, MaxRecurse);
3495 case Instruction::FSub:
3496 return SimplifyFSubInst(LHS, RHS, FMF, Q, MaxRecurse);
3497 case Instruction::FMul:
3498 return SimplifyFMulInst(LHS, RHS, FMF, Q, MaxRecurse);
3500 return SimplifyBinOp(Opcode, LHS, RHS, Q, MaxRecurse);
3504 Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
3505 const DataLayout *DL, const TargetLibraryInfo *TLI,
3506 const DominatorTree *DT, AssumptionCache *AC,
3507 const Instruction *CxtI) {
3508 return ::SimplifyBinOp(Opcode, LHS, RHS, Query(DL, TLI, DT, AC, CxtI),
3512 Value *llvm::SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
3513 const FastMathFlags &FMF, const DataLayout *DL,
3514 const TargetLibraryInfo *TLI,
3515 const DominatorTree *DT, AssumptionCache *AC,
3516 const Instruction *CxtI) {
3517 return ::SimplifyFPBinOp(Opcode, LHS, RHS, FMF, Query(DL, TLI, DT, AC, CxtI),
3521 /// SimplifyCmpInst - Given operands for a CmpInst, see if we can
3522 /// fold the result.
3523 static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3524 const Query &Q, unsigned MaxRecurse) {
3525 if (CmpInst::isIntPredicate((CmpInst::Predicate)Predicate))
3526 return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
3527 return SimplifyFCmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
3530 Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3531 const DataLayout *DL, const TargetLibraryInfo *TLI,
3532 const DominatorTree *DT, AssumptionCache *AC,
3533 const Instruction *CxtI) {
3534 return ::SimplifyCmpInst(Predicate, LHS, RHS, Query(DL, TLI, DT, AC, CxtI),
3538 static bool IsIdempotent(Intrinsic::ID ID) {
3540 default: return false;
3542 // Unary idempotent: f(f(x)) = f(x)
3543 case Intrinsic::fabs:
3544 case Intrinsic::floor:
3545 case Intrinsic::ceil:
3546 case Intrinsic::trunc:
3547 case Intrinsic::rint:
3548 case Intrinsic::nearbyint:
3549 case Intrinsic::round:
3554 template <typename IterTy>
3555 static Value *SimplifyIntrinsic(Intrinsic::ID IID, IterTy ArgBegin, IterTy ArgEnd,
3556 const Query &Q, unsigned MaxRecurse) {
3557 // Perform idempotent optimizations
3558 if (!IsIdempotent(IID))
3562 if (std::distance(ArgBegin, ArgEnd) == 1)
3563 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(*ArgBegin))
3564 if (II->getIntrinsicID() == IID)
3570 template <typename IterTy>
3571 static Value *SimplifyCall(Value *V, IterTy ArgBegin, IterTy ArgEnd,
3572 const Query &Q, unsigned MaxRecurse) {
3573 Type *Ty = V->getType();
3574 if (PointerType *PTy = dyn_cast<PointerType>(Ty))
3575 Ty = PTy->getElementType();
3576 FunctionType *FTy = cast<FunctionType>(Ty);
3578 // call undef -> undef
3579 if (isa<UndefValue>(V))
3580 return UndefValue::get(FTy->getReturnType());
3582 Function *F = dyn_cast<Function>(V);
3586 if (unsigned IID = F->getIntrinsicID())
3588 SimplifyIntrinsic((Intrinsic::ID) IID, ArgBegin, ArgEnd, Q, MaxRecurse))
3591 if (!canConstantFoldCallTo(F))
3594 SmallVector<Constant *, 4> ConstantArgs;
3595 ConstantArgs.reserve(ArgEnd - ArgBegin);
3596 for (IterTy I = ArgBegin, E = ArgEnd; I != E; ++I) {
3597 Constant *C = dyn_cast<Constant>(*I);
3600 ConstantArgs.push_back(C);
3603 return ConstantFoldCall(F, ConstantArgs, Q.TLI);
3606 Value *llvm::SimplifyCall(Value *V, User::op_iterator ArgBegin,
3607 User::op_iterator ArgEnd, const DataLayout *DL,
3608 const TargetLibraryInfo *TLI, const DominatorTree *DT,
3609 AssumptionCache *AC, const Instruction *CxtI) {
3610 return ::SimplifyCall(V, ArgBegin, ArgEnd, Query(DL, TLI, DT, AC, CxtI),
3614 Value *llvm::SimplifyCall(Value *V, ArrayRef<Value *> Args,
3615 const DataLayout *DL, const TargetLibraryInfo *TLI,
3616 const DominatorTree *DT, AssumptionCache *AC,
3617 const Instruction *CxtI) {
3618 return ::SimplifyCall(V, Args.begin(), Args.end(),
3619 Query(DL, TLI, DT, AC, CxtI), RecursionLimit);
3622 /// SimplifyInstruction - See if we can compute a simplified version of this
3623 /// instruction. If not, this returns null.
3624 Value *llvm::SimplifyInstruction(Instruction *I, const DataLayout *DL,
3625 const TargetLibraryInfo *TLI,
3626 const DominatorTree *DT, AssumptionCache *AC) {
3629 switch (I->getOpcode()) {
3631 Result = ConstantFoldInstruction(I, DL, TLI);
3633 case Instruction::FAdd:
3634 Result = SimplifyFAddInst(I->getOperand(0), I->getOperand(1),
3635 I->getFastMathFlags(), DL, TLI, DT, AC, I);
3637 case Instruction::Add:
3638 Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
3639 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3640 cast<BinaryOperator>(I)->hasNoUnsignedWrap(), DL,
3643 case Instruction::FSub:
3644 Result = SimplifyFSubInst(I->getOperand(0), I->getOperand(1),
3645 I->getFastMathFlags(), DL, TLI, DT, AC, I);
3647 case Instruction::Sub:
3648 Result = SimplifySubInst(I->getOperand(0), I->getOperand(1),
3649 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3650 cast<BinaryOperator>(I)->hasNoUnsignedWrap(), DL,
3653 case Instruction::FMul:
3654 Result = SimplifyFMulInst(I->getOperand(0), I->getOperand(1),
3655 I->getFastMathFlags(), DL, TLI, DT, AC, I);
3657 case Instruction::Mul:
3659 SimplifyMulInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT, AC, I);
3661 case Instruction::SDiv:
3662 Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT,
3665 case Instruction::UDiv:
3666 Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT,
3669 case Instruction::FDiv:
3670 Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1),
3671 I->getFastMathFlags(), DL, TLI, DT, AC, I);
3673 case Instruction::SRem:
3674 Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT,
3677 case Instruction::URem:
3678 Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT,
3681 case Instruction::FRem:
3682 Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1),
3683 I->getFastMathFlags(), DL, TLI, DT, AC, I);
3685 case Instruction::Shl:
3686 Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1),
3687 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3688 cast<BinaryOperator>(I)->hasNoUnsignedWrap(), DL,
3691 case Instruction::LShr:
3692 Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
3693 cast<BinaryOperator>(I)->isExact(), DL, TLI, DT,
3696 case Instruction::AShr:
3697 Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
3698 cast<BinaryOperator>(I)->isExact(), DL, TLI, DT,
3701 case Instruction::And:
3703 SimplifyAndInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT, AC, I);
3705 case Instruction::Or:
3707 SimplifyOrInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT, AC, I);
3709 case Instruction::Xor:
3711 SimplifyXorInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT, AC, I);
3713 case Instruction::ICmp:
3715 SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(), I->getOperand(0),
3716 I->getOperand(1), DL, TLI, DT, AC, I);
3718 case Instruction::FCmp:
3720 SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(), I->getOperand(0),
3721 I->getOperand(1), DL, TLI, DT, AC, I);
3723 case Instruction::Select:
3724 Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
3725 I->getOperand(2), DL, TLI, DT, AC, I);
3727 case Instruction::GetElementPtr: {
3728 SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end());
3729 Result = SimplifyGEPInst(Ops, DL, TLI, DT, AC, I);
3732 case Instruction::InsertValue: {
3733 InsertValueInst *IV = cast<InsertValueInst>(I);
3734 Result = SimplifyInsertValueInst(IV->getAggregateOperand(),
3735 IV->getInsertedValueOperand(),
3736 IV->getIndices(), DL, TLI, DT, AC, I);
3739 case Instruction::PHI:
3740 Result = SimplifyPHINode(cast<PHINode>(I), Query(DL, TLI, DT, AC, I));
3742 case Instruction::Call: {
3743 CallSite CS(cast<CallInst>(I));
3744 Result = SimplifyCall(CS.getCalledValue(), CS.arg_begin(), CS.arg_end(), DL,
3748 case Instruction::Trunc:
3750 SimplifyTruncInst(I->getOperand(0), I->getType(), DL, TLI, DT, AC, I);
3754 /// If called on unreachable code, the above logic may report that the
3755 /// instruction simplified to itself. Make life easier for users by
3756 /// detecting that case here, returning a safe value instead.
3757 return Result == I ? UndefValue::get(I->getType()) : Result;
3760 /// \brief Implementation of recursive simplification through an instructions
3763 /// This is the common implementation of the recursive simplification routines.
3764 /// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
3765 /// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
3766 /// instructions to process and attempt to simplify it using
3767 /// InstructionSimplify.
3769 /// This routine returns 'true' only when *it* simplifies something. The passed
3770 /// in simplified value does not count toward this.
3771 static bool replaceAndRecursivelySimplifyImpl(Instruction *I, Value *SimpleV,
3772 const DataLayout *DL,
3773 const TargetLibraryInfo *TLI,
3774 const DominatorTree *DT,
3775 AssumptionCache *AC) {
3776 bool Simplified = false;
3777 SmallSetVector<Instruction *, 8> Worklist;
3779 // If we have an explicit value to collapse to, do that round of the
3780 // simplification loop by hand initially.
3782 for (User *U : I->users())
3784 Worklist.insert(cast<Instruction>(U));
3786 // Replace the instruction with its simplified value.
3787 I->replaceAllUsesWith(SimpleV);
3789 // Gracefully handle edge cases where the instruction is not wired into any
3792 I->eraseFromParent();
3797 // Note that we must test the size on each iteration, the worklist can grow.
3798 for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
3801 // See if this instruction simplifies.
3802 SimpleV = SimplifyInstruction(I, DL, TLI, DT, AC);
3808 // Stash away all the uses of the old instruction so we can check them for
3809 // recursive simplifications after a RAUW. This is cheaper than checking all
3810 // uses of To on the recursive step in most cases.
3811 for (User *U : I->users())
3812 Worklist.insert(cast<Instruction>(U));
3814 // Replace the instruction with its simplified value.
3815 I->replaceAllUsesWith(SimpleV);
3817 // Gracefully handle edge cases where the instruction is not wired into any
3820 I->eraseFromParent();
3825 bool llvm::recursivelySimplifyInstruction(Instruction *I, const DataLayout *DL,
3826 const TargetLibraryInfo *TLI,
3827 const DominatorTree *DT,
3828 AssumptionCache *AC) {
3829 return replaceAndRecursivelySimplifyImpl(I, nullptr, DL, TLI, DT, AC);
3832 bool llvm::replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV,
3833 const DataLayout *DL,
3834 const TargetLibraryInfo *TLI,
3835 const DominatorTree *DT,
3836 AssumptionCache *AC) {
3837 assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!");
3838 assert(SimpleV && "Must provide a simplified value.");
3839 return replaceAndRecursivelySimplifyImpl(I, SimpleV, DL, TLI, DT, AC);