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/ConstantFolding.h"
24 #include "llvm/Analysis/MemoryBuiltins.h"
25 #include "llvm/Analysis/ValueTracking.h"
26 #include "llvm/IR/ConstantRange.h"
27 #include "llvm/IR/DataLayout.h"
28 #include "llvm/IR/Dominators.h"
29 #include "llvm/IR/GetElementPtrTypeIterator.h"
30 #include "llvm/IR/GlobalAlias.h"
31 #include "llvm/IR/Operator.h"
32 #include "llvm/IR/PatternMatch.h"
33 #include "llvm/IR/ValueHandle.h"
35 using namespace llvm::PatternMatch;
37 #define DEBUG_TYPE "instsimplify"
39 enum { RecursionLimit = 3 };
41 STATISTIC(NumExpand, "Number of expansions");
42 STATISTIC(NumReassoc, "Number of reassociations");
47 const TargetLibraryInfo *TLI;
48 const DominatorTree *DT;
49 AssumptionTracker *AT;
50 const Instruction *CxtI;
52 Query(const DataLayout *DL, const TargetLibraryInfo *tli,
53 const DominatorTree *dt, AssumptionTracker *at = nullptr,
54 const Instruction *cxti = nullptr)
55 : DL(DL), TLI(tli), DT(dt), AT(at), CxtI(cxti) {}
57 } // end anonymous namespace
59 static Value *SimplifyAndInst(Value *, Value *, const Query &, unsigned);
60 static Value *SimplifyBinOp(unsigned, Value *, Value *, const Query &,
62 static Value *SimplifyCmpInst(unsigned, Value *, Value *, const Query &,
64 static Value *SimplifyOrInst(Value *, Value *, const Query &, unsigned);
65 static Value *SimplifyXorInst(Value *, Value *, const Query &, unsigned);
66 static Value *SimplifyTruncInst(Value *, Type *, const Query &, unsigned);
68 /// getFalse - For a boolean type, or a vector of boolean type, return false, or
69 /// a vector with every element false, as appropriate for the type.
70 static Constant *getFalse(Type *Ty) {
71 assert(Ty->getScalarType()->isIntegerTy(1) &&
72 "Expected i1 type or a vector of i1!");
73 return Constant::getNullValue(Ty);
76 /// getTrue - For a boolean type, or a vector of boolean type, return true, or
77 /// a vector with every element true, as appropriate for the type.
78 static Constant *getTrue(Type *Ty) {
79 assert(Ty->getScalarType()->isIntegerTy(1) &&
80 "Expected i1 type or a vector of i1!");
81 return Constant::getAllOnesValue(Ty);
84 /// isSameCompare - Is V equivalent to the comparison "LHS Pred RHS"?
85 static bool isSameCompare(Value *V, CmpInst::Predicate Pred, Value *LHS,
87 CmpInst *Cmp = dyn_cast<CmpInst>(V);
90 CmpInst::Predicate CPred = Cmp->getPredicate();
91 Value *CLHS = Cmp->getOperand(0), *CRHS = Cmp->getOperand(1);
92 if (CPred == Pred && CLHS == LHS && CRHS == RHS)
94 return CPred == CmpInst::getSwappedPredicate(Pred) && CLHS == RHS &&
98 /// ValueDominatesPHI - Does the given value dominate the specified phi node?
99 static bool ValueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
100 Instruction *I = dyn_cast<Instruction>(V);
102 // Arguments and constants dominate all instructions.
105 // If we are processing instructions (and/or basic blocks) that have not been
106 // fully added to a function, the parent nodes may still be null. Simply
107 // return the conservative answer in these cases.
108 if (!I->getParent() || !P->getParent() || !I->getParent()->getParent())
111 // If we have a DominatorTree then do a precise test.
113 if (!DT->isReachableFromEntry(P->getParent()))
115 if (!DT->isReachableFromEntry(I->getParent()))
117 return DT->dominates(I, P);
120 // Otherwise, if the instruction is in the entry block, and is not an invoke,
121 // then it obviously dominates all phi nodes.
122 if (I->getParent() == &I->getParent()->getParent()->getEntryBlock() &&
129 /// ExpandBinOp - Simplify "A op (B op' C)" by distributing op over op', turning
130 /// it into "(A op B) op' (A op C)". Here "op" is given by Opcode and "op'" is
131 /// given by OpcodeToExpand, while "A" corresponds to LHS and "B op' C" to RHS.
132 /// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)".
133 /// Returns the simplified value, or null if no simplification was performed.
134 static Value *ExpandBinOp(unsigned Opcode, Value *LHS, Value *RHS,
135 unsigned OpcToExpand, const Query &Q,
136 unsigned MaxRecurse) {
137 Instruction::BinaryOps OpcodeToExpand = (Instruction::BinaryOps)OpcToExpand;
138 // Recursion is always used, so bail out at once if we already hit the limit.
142 // Check whether the expression has the form "(A op' B) op C".
143 if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS))
144 if (Op0->getOpcode() == OpcodeToExpand) {
145 // It does! Try turning it into "(A op C) op' (B op C)".
146 Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS;
147 // Do "A op C" and "B op C" both simplify?
148 if (Value *L = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse))
149 if (Value *R = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
150 // They do! Return "L op' R" if it simplifies or is already available.
151 // If "L op' R" equals "A op' B" then "L op' R" is just the LHS.
152 if ((L == A && R == B) || (Instruction::isCommutative(OpcodeToExpand)
153 && L == B && R == A)) {
157 // Otherwise return "L op' R" if it simplifies.
158 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
165 // Check whether the expression has the form "A op (B op' C)".
166 if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS))
167 if (Op1->getOpcode() == OpcodeToExpand) {
168 // It does! Try turning it into "(A op B) op' (A op C)".
169 Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1);
170 // Do "A op B" and "A op C" both simplify?
171 if (Value *L = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse))
172 if (Value *R = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse)) {
173 // They do! Return "L op' R" if it simplifies or is already available.
174 // If "L op' R" equals "B op' C" then "L op' R" is just the RHS.
175 if ((L == B && R == C) || (Instruction::isCommutative(OpcodeToExpand)
176 && L == C && R == B)) {
180 // Otherwise return "L op' R" if it simplifies.
181 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
191 /// SimplifyAssociativeBinOp - Generic simplifications for associative binary
192 /// operations. Returns the simpler value, or null if none was found.
193 static Value *SimplifyAssociativeBinOp(unsigned Opc, Value *LHS, Value *RHS,
194 const Query &Q, unsigned MaxRecurse) {
195 Instruction::BinaryOps Opcode = (Instruction::BinaryOps)Opc;
196 assert(Instruction::isAssociative(Opcode) && "Not an associative operation!");
198 // Recursion is always used, so bail out at once if we already hit the limit.
202 BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
203 BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
205 // Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely.
206 if (Op0 && Op0->getOpcode() == Opcode) {
207 Value *A = Op0->getOperand(0);
208 Value *B = Op0->getOperand(1);
211 // Does "B op C" simplify?
212 if (Value *V = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
213 // It does! Return "A op V" if it simplifies or is already available.
214 // If V equals B then "A op V" is just the LHS.
215 if (V == B) return LHS;
216 // Otherwise return "A op V" if it simplifies.
217 if (Value *W = SimplifyBinOp(Opcode, A, V, Q, MaxRecurse)) {
224 // Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely.
225 if (Op1 && Op1->getOpcode() == Opcode) {
227 Value *B = Op1->getOperand(0);
228 Value *C = Op1->getOperand(1);
230 // Does "A op B" simplify?
231 if (Value *V = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse)) {
232 // It does! Return "V op C" if it simplifies or is already available.
233 // If V equals B then "V op C" is just the RHS.
234 if (V == B) return RHS;
235 // Otherwise return "V op C" if it simplifies.
236 if (Value *W = SimplifyBinOp(Opcode, V, C, Q, MaxRecurse)) {
243 // The remaining transforms require commutativity as well as associativity.
244 if (!Instruction::isCommutative(Opcode))
247 // Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely.
248 if (Op0 && Op0->getOpcode() == Opcode) {
249 Value *A = Op0->getOperand(0);
250 Value *B = Op0->getOperand(1);
253 // Does "C op A" simplify?
254 if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
255 // It does! Return "V op B" if it simplifies or is already available.
256 // If V equals A then "V op B" is just the LHS.
257 if (V == A) return LHS;
258 // Otherwise return "V op B" if it simplifies.
259 if (Value *W = SimplifyBinOp(Opcode, V, B, Q, MaxRecurse)) {
266 // Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely.
267 if (Op1 && Op1->getOpcode() == Opcode) {
269 Value *B = Op1->getOperand(0);
270 Value *C = Op1->getOperand(1);
272 // Does "C op A" simplify?
273 if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
274 // It does! Return "B op V" if it simplifies or is already available.
275 // If V equals C then "B op V" is just the RHS.
276 if (V == C) return RHS;
277 // Otherwise return "B op V" if it simplifies.
278 if (Value *W = SimplifyBinOp(Opcode, B, V, Q, MaxRecurse)) {
288 /// ThreadBinOpOverSelect - In the case of a binary operation with a select
289 /// instruction as an operand, try to simplify the binop by seeing whether
290 /// evaluating it on both branches of the select results in the same value.
291 /// Returns the common value if so, otherwise returns null.
292 static Value *ThreadBinOpOverSelect(unsigned Opcode, Value *LHS, Value *RHS,
293 const Query &Q, unsigned MaxRecurse) {
294 // Recursion is always used, so bail out at once if we already hit the limit.
299 if (isa<SelectInst>(LHS)) {
300 SI = cast<SelectInst>(LHS);
302 assert(isa<SelectInst>(RHS) && "No select instruction operand!");
303 SI = cast<SelectInst>(RHS);
306 // Evaluate the BinOp on the true and false branches of the select.
310 TV = SimplifyBinOp(Opcode, SI->getTrueValue(), RHS, Q, MaxRecurse);
311 FV = SimplifyBinOp(Opcode, SI->getFalseValue(), RHS, Q, MaxRecurse);
313 TV = SimplifyBinOp(Opcode, LHS, SI->getTrueValue(), Q, MaxRecurse);
314 FV = SimplifyBinOp(Opcode, LHS, SI->getFalseValue(), Q, MaxRecurse);
317 // If they simplified to the same value, then return the common value.
318 // If they both failed to simplify then return null.
322 // If one branch simplified to undef, return the other one.
323 if (TV && isa<UndefValue>(TV))
325 if (FV && isa<UndefValue>(FV))
328 // If applying the operation did not change the true and false select values,
329 // then the result of the binop is the select itself.
330 if (TV == SI->getTrueValue() && FV == SI->getFalseValue())
333 // If one branch simplified and the other did not, and the simplified
334 // value is equal to the unsimplified one, return the simplified value.
335 // For example, select (cond, X, X & Z) & Z -> X & Z.
336 if ((FV && !TV) || (TV && !FV)) {
337 // Check that the simplified value has the form "X op Y" where "op" is the
338 // same as the original operation.
339 Instruction *Simplified = dyn_cast<Instruction>(FV ? FV : TV);
340 if (Simplified && Simplified->getOpcode() == Opcode) {
341 // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS".
342 // We already know that "op" is the same as for the simplified value. See
343 // if the operands match too. If so, return the simplified value.
344 Value *UnsimplifiedBranch = FV ? SI->getTrueValue() : SI->getFalseValue();
345 Value *UnsimplifiedLHS = SI == LHS ? UnsimplifiedBranch : LHS;
346 Value *UnsimplifiedRHS = SI == LHS ? RHS : UnsimplifiedBranch;
347 if (Simplified->getOperand(0) == UnsimplifiedLHS &&
348 Simplified->getOperand(1) == UnsimplifiedRHS)
350 if (Simplified->isCommutative() &&
351 Simplified->getOperand(1) == UnsimplifiedLHS &&
352 Simplified->getOperand(0) == UnsimplifiedRHS)
360 /// ThreadCmpOverSelect - In the case of a comparison with a select instruction,
361 /// try to simplify the comparison by seeing whether both branches of the select
362 /// result in the same value. Returns the common value if so, otherwise returns
364 static Value *ThreadCmpOverSelect(CmpInst::Predicate Pred, Value *LHS,
365 Value *RHS, const Query &Q,
366 unsigned MaxRecurse) {
367 // Recursion is always used, so bail out at once if we already hit the limit.
371 // Make sure the select is on the LHS.
372 if (!isa<SelectInst>(LHS)) {
374 Pred = CmpInst::getSwappedPredicate(Pred);
376 assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!");
377 SelectInst *SI = cast<SelectInst>(LHS);
378 Value *Cond = SI->getCondition();
379 Value *TV = SI->getTrueValue();
380 Value *FV = SI->getFalseValue();
382 // Now that we have "cmp select(Cond, TV, FV), RHS", analyse it.
383 // Does "cmp TV, RHS" simplify?
384 Value *TCmp = SimplifyCmpInst(Pred, TV, RHS, Q, MaxRecurse);
386 // It not only simplified, it simplified to the select condition. Replace
388 TCmp = getTrue(Cond->getType());
390 // It didn't simplify. However if "cmp TV, RHS" is equal to the select
391 // condition then we can replace it with 'true'. Otherwise give up.
392 if (!isSameCompare(Cond, Pred, TV, RHS))
394 TCmp = getTrue(Cond->getType());
397 // Does "cmp FV, RHS" simplify?
398 Value *FCmp = SimplifyCmpInst(Pred, FV, RHS, Q, MaxRecurse);
400 // It not only simplified, it simplified to the select condition. Replace
402 FCmp = getFalse(Cond->getType());
404 // It didn't simplify. However if "cmp FV, RHS" is equal to the select
405 // condition then we can replace it with 'false'. Otherwise give up.
406 if (!isSameCompare(Cond, Pred, FV, RHS))
408 FCmp = getFalse(Cond->getType());
411 // If both sides simplified to the same value, then use it as the result of
412 // the original comparison.
416 // The remaining cases only make sense if the select condition has the same
417 // type as the result of the comparison, so bail out if this is not so.
418 if (Cond->getType()->isVectorTy() != RHS->getType()->isVectorTy())
420 // If the false value simplified to false, then the result of the compare
421 // is equal to "Cond && TCmp". This also catches the case when the false
422 // value simplified to false and the true value to true, returning "Cond".
423 if (match(FCmp, m_Zero()))
424 if (Value *V = SimplifyAndInst(Cond, TCmp, Q, MaxRecurse))
426 // If the true value simplified to true, then the result of the compare
427 // is equal to "Cond || FCmp".
428 if (match(TCmp, m_One()))
429 if (Value *V = SimplifyOrInst(Cond, FCmp, Q, MaxRecurse))
431 // Finally, if the false value simplified to true and the true value to
432 // false, then the result of the compare is equal to "!Cond".
433 if (match(FCmp, m_One()) && match(TCmp, m_Zero()))
435 SimplifyXorInst(Cond, Constant::getAllOnesValue(Cond->getType()),
442 /// ThreadBinOpOverPHI - In the case of a binary operation with an operand that
443 /// is a PHI instruction, try to simplify the binop by seeing whether evaluating
444 /// it on the incoming phi values yields the same result for every value. If so
445 /// returns the common value, otherwise returns null.
446 static Value *ThreadBinOpOverPHI(unsigned Opcode, Value *LHS, Value *RHS,
447 const Query &Q, unsigned MaxRecurse) {
448 // Recursion is always used, so bail out at once if we already hit the limit.
453 if (isa<PHINode>(LHS)) {
454 PI = cast<PHINode>(LHS);
455 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
456 if (!ValueDominatesPHI(RHS, PI, Q.DT))
459 assert(isa<PHINode>(RHS) && "No PHI instruction operand!");
460 PI = cast<PHINode>(RHS);
461 // Bail out if LHS and the phi may be mutually interdependent due to a loop.
462 if (!ValueDominatesPHI(LHS, PI, Q.DT))
466 // Evaluate the BinOp on the incoming phi values.
467 Value *CommonValue = nullptr;
468 for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
469 Value *Incoming = PI->getIncomingValue(i);
470 // If the incoming value is the phi node itself, it can safely be skipped.
471 if (Incoming == PI) continue;
472 Value *V = PI == LHS ?
473 SimplifyBinOp(Opcode, Incoming, RHS, Q, MaxRecurse) :
474 SimplifyBinOp(Opcode, LHS, Incoming, Q, MaxRecurse);
475 // If the operation failed to simplify, or simplified to a different value
476 // to previously, then give up.
477 if (!V || (CommonValue && V != CommonValue))
485 /// ThreadCmpOverPHI - In the case of a comparison with a PHI instruction, try
486 /// try to simplify the comparison by seeing whether comparing with all of the
487 /// incoming phi values yields the same result every time. If so returns the
488 /// common result, otherwise returns null.
489 static Value *ThreadCmpOverPHI(CmpInst::Predicate Pred, Value *LHS, Value *RHS,
490 const Query &Q, unsigned MaxRecurse) {
491 // Recursion is always used, so bail out at once if we already hit the limit.
495 // Make sure the phi is on the LHS.
496 if (!isa<PHINode>(LHS)) {
498 Pred = CmpInst::getSwappedPredicate(Pred);
500 assert(isa<PHINode>(LHS) && "Not comparing with a phi instruction!");
501 PHINode *PI = cast<PHINode>(LHS);
503 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
504 if (!ValueDominatesPHI(RHS, PI, Q.DT))
507 // Evaluate the BinOp on the incoming phi values.
508 Value *CommonValue = nullptr;
509 for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
510 Value *Incoming = PI->getIncomingValue(i);
511 // If the incoming value is the phi node itself, it can safely be skipped.
512 if (Incoming == PI) continue;
513 Value *V = SimplifyCmpInst(Pred, Incoming, RHS, Q, MaxRecurse);
514 // If the operation failed to simplify, or simplified to a different value
515 // to previously, then give up.
516 if (!V || (CommonValue && V != CommonValue))
524 /// SimplifyAddInst - Given operands for an Add, see if we can
525 /// fold the result. If not, this returns null.
526 static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
527 const Query &Q, unsigned MaxRecurse) {
528 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
529 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
530 Constant *Ops[] = { CLHS, CRHS };
531 return ConstantFoldInstOperands(Instruction::Add, CLHS->getType(), Ops,
535 // Canonicalize the constant to the RHS.
539 // X + undef -> undef
540 if (match(Op1, m_Undef()))
544 if (match(Op1, m_Zero()))
551 if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) ||
552 match(Op0, m_Sub(m_Value(Y), m_Specific(Op1))))
555 // X + ~X -> -1 since ~X = -X-1
556 if (match(Op0, m_Not(m_Specific(Op1))) ||
557 match(Op1, m_Not(m_Specific(Op0))))
558 return Constant::getAllOnesValue(Op0->getType());
561 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
562 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
565 // Try some generic simplifications for associative operations.
566 if (Value *V = SimplifyAssociativeBinOp(Instruction::Add, Op0, Op1, Q,
570 // Threading Add over selects and phi nodes is pointless, so don't bother.
571 // Threading over the select in "A + select(cond, B, C)" means evaluating
572 // "A+B" and "A+C" and seeing if they are equal; but they are equal if and
573 // only if B and C are equal. If B and C are equal then (since we assume
574 // that operands have already been simplified) "select(cond, B, C)" should
575 // have been simplified to the common value of B and C already. Analysing
576 // "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly
577 // for threading over phi nodes.
582 Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
583 const DataLayout *DL, const TargetLibraryInfo *TLI,
584 const DominatorTree *DT, AssumptionTracker *AT,
585 const Instruction *CxtI) {
586 return ::SimplifyAddInst(Op0, Op1, isNSW, isNUW,
587 Query (DL, TLI, DT, AT, CxtI), RecursionLimit);
590 /// \brief Compute the base pointer and cumulative constant offsets for V.
592 /// This strips all constant offsets off of V, leaving it the base pointer, and
593 /// accumulates the total constant offset applied in the returned constant. It
594 /// returns 0 if V is not a pointer, and returns the constant '0' if there are
595 /// no constant offsets applied.
597 /// This is very similar to GetPointerBaseWithConstantOffset except it doesn't
598 /// follow non-inbounds geps. This allows it to remain usable for icmp ult/etc.
600 static Constant *stripAndComputeConstantOffsets(const DataLayout *DL,
602 bool AllowNonInbounds = false) {
603 assert(V->getType()->getScalarType()->isPointerTy());
605 // Without DataLayout, just be conservative for now. Theoretically, more could
606 // be done in this case.
608 return ConstantInt::get(IntegerType::get(V->getContext(), 64), 0);
610 Type *IntPtrTy = DL->getIntPtrType(V->getType())->getScalarType();
611 APInt Offset = APInt::getNullValue(IntPtrTy->getIntegerBitWidth());
613 // Even though we don't look through PHI nodes, we could be called on an
614 // instruction in an unreachable block, which may be on a cycle.
615 SmallPtrSet<Value *, 4> Visited;
618 if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
619 if ((!AllowNonInbounds && !GEP->isInBounds()) ||
620 !GEP->accumulateConstantOffset(*DL, Offset))
622 V = GEP->getPointerOperand();
623 } else if (Operator::getOpcode(V) == Instruction::BitCast) {
624 V = cast<Operator>(V)->getOperand(0);
625 } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
626 if (GA->mayBeOverridden())
628 V = GA->getAliasee();
632 assert(V->getType()->getScalarType()->isPointerTy() &&
633 "Unexpected operand type!");
634 } while (Visited.insert(V));
636 Constant *OffsetIntPtr = ConstantInt::get(IntPtrTy, Offset);
637 if (V->getType()->isVectorTy())
638 return ConstantVector::getSplat(V->getType()->getVectorNumElements(),
643 /// \brief Compute the constant difference between two pointer values.
644 /// If the difference is not a constant, returns zero.
645 static Constant *computePointerDifference(const DataLayout *DL,
646 Value *LHS, Value *RHS) {
647 Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
648 Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
650 // If LHS and RHS are not related via constant offsets to the same base
651 // value, there is nothing we can do here.
655 // Otherwise, the difference of LHS - RHS can be computed as:
657 // = (LHSOffset + Base) - (RHSOffset + Base)
658 // = LHSOffset - RHSOffset
659 return ConstantExpr::getSub(LHSOffset, RHSOffset);
662 /// SimplifySubInst - Given operands for a Sub, see if we can
663 /// fold the result. If not, this returns null.
664 static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
665 const Query &Q, unsigned MaxRecurse) {
666 if (Constant *CLHS = dyn_cast<Constant>(Op0))
667 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
668 Constant *Ops[] = { CLHS, CRHS };
669 return ConstantFoldInstOperands(Instruction::Sub, CLHS->getType(),
673 // X - undef -> undef
674 // undef - X -> undef
675 if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
676 return UndefValue::get(Op0->getType());
679 if (match(Op1, m_Zero()))
684 return Constant::getNullValue(Op0->getType());
686 // X - (0 - Y) -> X if the second sub is NUW.
687 // If Y != 0, 0 - Y is a poison value.
688 // If Y == 0, 0 - Y simplifies to 0.
689 if (BinaryOperator::isNeg(Op1)) {
690 if (const auto *BO = dyn_cast<BinaryOperator>(Op1)) {
691 assert(BO->getOpcode() == Instruction::Sub &&
692 "Expected a subtraction operator!");
693 if (BO->hasNoUnsignedWrap())
698 // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
699 // For example, (X + Y) - Y -> X; (Y + X) - Y -> X
700 Value *X = nullptr, *Y = nullptr, *Z = Op1;
701 if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z
702 // See if "V === Y - Z" simplifies.
703 if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, Q, MaxRecurse-1))
704 // It does! Now see if "X + V" simplifies.
705 if (Value *W = SimplifyBinOp(Instruction::Add, X, V, Q, MaxRecurse-1)) {
706 // It does, we successfully reassociated!
710 // See if "V === X - Z" simplifies.
711 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
712 // It does! Now see if "Y + V" simplifies.
713 if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, Q, MaxRecurse-1)) {
714 // It does, we successfully reassociated!
720 // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
721 // For example, X - (X + 1) -> -1
723 if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z)
724 // See if "V === X - Y" simplifies.
725 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
726 // It does! Now see if "V - Z" simplifies.
727 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, Q, MaxRecurse-1)) {
728 // It does, we successfully reassociated!
732 // See if "V === X - Z" simplifies.
733 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
734 // It does! Now see if "V - Y" simplifies.
735 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, Q, MaxRecurse-1)) {
736 // It does, we successfully reassociated!
742 // Z - (X - Y) -> (Z - X) + Y if everything simplifies.
743 // For example, X - (X - Y) -> Y.
745 if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y)
746 // See if "V === Z - X" simplifies.
747 if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, Q, MaxRecurse-1))
748 // It does! Now see if "V + Y" simplifies.
749 if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, Q, MaxRecurse-1)) {
750 // It does, we successfully reassociated!
755 // trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies.
756 if (MaxRecurse && match(Op0, m_Trunc(m_Value(X))) &&
757 match(Op1, m_Trunc(m_Value(Y))))
758 if (X->getType() == Y->getType())
759 // See if "V === X - Y" simplifies.
760 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
761 // It does! Now see if "trunc V" simplifies.
762 if (Value *W = SimplifyTruncInst(V, Op0->getType(), Q, MaxRecurse-1))
763 // It does, return the simplified "trunc V".
766 // Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...).
767 if (match(Op0, m_PtrToInt(m_Value(X))) &&
768 match(Op1, m_PtrToInt(m_Value(Y))))
769 if (Constant *Result = computePointerDifference(Q.DL, X, Y))
770 return ConstantExpr::getIntegerCast(Result, Op0->getType(), true);
773 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
774 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
777 // Threading Sub over selects and phi nodes is pointless, so don't bother.
778 // Threading over the select in "A - select(cond, B, C)" means evaluating
779 // "A-B" and "A-C" and seeing if they are equal; but they are equal if and
780 // only if B and C are equal. If B and C are equal then (since we assume
781 // that operands have already been simplified) "select(cond, B, C)" should
782 // have been simplified to the common value of B and C already. Analysing
783 // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly
784 // for threading over phi nodes.
789 Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
790 const DataLayout *DL, const TargetLibraryInfo *TLI,
791 const DominatorTree *DT, AssumptionTracker *AT,
792 const Instruction *CxtI) {
793 return ::SimplifySubInst(Op0, Op1, isNSW, isNUW,
794 Query (DL, TLI, DT, AT, CxtI), RecursionLimit);
797 /// Given operands for an FAdd, see if we can fold the result. If not, this
799 static Value *SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
800 const Query &Q, unsigned MaxRecurse) {
801 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
802 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
803 Constant *Ops[] = { CLHS, CRHS };
804 return ConstantFoldInstOperands(Instruction::FAdd, CLHS->getType(),
808 // Canonicalize the constant to the RHS.
813 if (match(Op1, m_NegZero()))
816 // fadd X, 0 ==> X, when we know X is not -0
817 if (match(Op1, m_Zero()) &&
818 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
821 // fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
822 // where nnan and ninf have to occur at least once somewhere in this
824 Value *SubOp = nullptr;
825 if (match(Op1, m_FSub(m_AnyZero(), m_Specific(Op0))))
827 else if (match(Op0, m_FSub(m_AnyZero(), m_Specific(Op1))))
830 Instruction *FSub = cast<Instruction>(SubOp);
831 if ((FMF.noNaNs() || FSub->hasNoNaNs()) &&
832 (FMF.noInfs() || FSub->hasNoInfs()))
833 return Constant::getNullValue(Op0->getType());
839 /// Given operands for an FSub, see if we can fold the result. If not, this
841 static Value *SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
842 const Query &Q, unsigned MaxRecurse) {
843 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
844 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
845 Constant *Ops[] = { CLHS, CRHS };
846 return ConstantFoldInstOperands(Instruction::FSub, CLHS->getType(),
852 if (match(Op1, m_Zero()))
855 // fsub X, -0 ==> X, when we know X is not -0
856 if (match(Op1, m_NegZero()) &&
857 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
860 // fsub 0, (fsub -0.0, X) ==> X
862 if (match(Op0, m_AnyZero())) {
863 if (match(Op1, m_FSub(m_NegZero(), m_Value(X))))
865 if (FMF.noSignedZeros() && match(Op1, m_FSub(m_AnyZero(), m_Value(X))))
869 // fsub nnan ninf x, x ==> 0.0
870 if (FMF.noNaNs() && FMF.noInfs() && Op0 == Op1)
871 return Constant::getNullValue(Op0->getType());
876 /// Given the operands for an FMul, see if we can fold the result
877 static Value *SimplifyFMulInst(Value *Op0, Value *Op1,
880 unsigned MaxRecurse) {
881 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
882 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
883 Constant *Ops[] = { CLHS, CRHS };
884 return ConstantFoldInstOperands(Instruction::FMul, CLHS->getType(),
888 // Canonicalize the constant to the RHS.
893 if (match(Op1, m_FPOne()))
896 // fmul nnan nsz X, 0 ==> 0
897 if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZero()))
903 /// SimplifyMulInst - Given operands for a Mul, see if we can
904 /// fold the result. If not, this returns null.
905 static Value *SimplifyMulInst(Value *Op0, Value *Op1, const Query &Q,
906 unsigned MaxRecurse) {
907 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
908 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
909 Constant *Ops[] = { CLHS, CRHS };
910 return ConstantFoldInstOperands(Instruction::Mul, CLHS->getType(),
914 // Canonicalize the constant to the RHS.
919 if (match(Op1, m_Undef()))
920 return Constant::getNullValue(Op0->getType());
923 if (match(Op1, m_Zero()))
927 if (match(Op1, m_One()))
930 // (X / Y) * Y -> X if the division is exact.
932 if (match(Op0, m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y
933 match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0))))) // Y * (X / Y)
937 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
938 if (Value *V = SimplifyAndInst(Op0, Op1, Q, MaxRecurse-1))
941 // Try some generic simplifications for associative operations.
942 if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, Q,
946 // Mul distributes over Add. Try some generic simplifications based on this.
947 if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add,
951 // If the operation is with the result of a select instruction, check whether
952 // operating on either branch of the select always yields the same value.
953 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
954 if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, Q,
958 // If the operation is with the result of a phi instruction, check whether
959 // operating on all incoming values of the phi always yields the same value.
960 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
961 if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, Q,
968 Value *llvm::SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
969 const DataLayout *DL, const TargetLibraryInfo *TLI,
970 const DominatorTree *DT, AssumptionTracker *AT,
971 const Instruction *CxtI) {
972 return ::SimplifyFAddInst(Op0, Op1, FMF, Query (DL, TLI, DT, AT, CxtI),
976 Value *llvm::SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
977 const DataLayout *DL, const TargetLibraryInfo *TLI,
978 const DominatorTree *DT, AssumptionTracker *AT,
979 const Instruction *CxtI) {
980 return ::SimplifyFSubInst(Op0, Op1, FMF, Query (DL, TLI, DT, AT, CxtI),
984 Value *llvm::SimplifyFMulInst(Value *Op0, Value *Op1,
986 const DataLayout *DL,
987 const TargetLibraryInfo *TLI,
988 const DominatorTree *DT,
989 AssumptionTracker *AT,
990 const Instruction *CxtI) {
991 return ::SimplifyFMulInst(Op0, Op1, FMF, Query (DL, TLI, DT, AT, CxtI),
995 Value *llvm::SimplifyMulInst(Value *Op0, Value *Op1, const DataLayout *DL,
996 const TargetLibraryInfo *TLI,
997 const DominatorTree *DT, AssumptionTracker *AT,
998 const Instruction *CxtI) {
999 return ::SimplifyMulInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1003 /// SimplifyDiv - Given operands for an SDiv or UDiv, see if we can
1004 /// fold the result. If not, this returns null.
1005 static Value *SimplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
1006 const Query &Q, unsigned MaxRecurse) {
1007 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1008 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1009 Constant *Ops[] = { C0, C1 };
1010 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.DL, Q.TLI);
1014 bool isSigned = Opcode == Instruction::SDiv;
1016 // X / undef -> undef
1017 if (match(Op1, m_Undef()))
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,
1098 AssumptionTracker *AT,
1099 const Instruction *CxtI) {
1100 return ::SimplifySDivInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1104 /// SimplifyUDivInst - Given operands for a UDiv, see if we can
1105 /// fold the result. If not, this returns null.
1106 static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const Query &Q,
1107 unsigned MaxRecurse) {
1108 if (Value *V = SimplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse))
1114 Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const DataLayout *DL,
1115 const TargetLibraryInfo *TLI,
1116 const DominatorTree *DT,
1117 AssumptionTracker *AT,
1118 const Instruction *CxtI) {
1119 return ::SimplifyUDivInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1123 static Value *SimplifyFDivInst(Value *Op0, Value *Op1, const Query &Q,
1125 // undef / X -> undef (the undef could be a snan).
1126 if (match(Op0, m_Undef()))
1129 // X / undef -> undef
1130 if (match(Op1, m_Undef()))
1136 Value *llvm::SimplifyFDivInst(Value *Op0, Value *Op1, const DataLayout *DL,
1137 const TargetLibraryInfo *TLI,
1138 const DominatorTree *DT,
1139 AssumptionTracker *AT,
1140 const Instruction *CxtI) {
1141 return ::SimplifyFDivInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1145 /// SimplifyRem - Given operands for an SRem or URem, see if we can
1146 /// fold the result. If not, this returns null.
1147 static Value *SimplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
1148 const Query &Q, unsigned MaxRecurse) {
1149 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1150 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1151 Constant *Ops[] = { C0, C1 };
1152 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.DL, Q.TLI);
1156 // X % undef -> undef
1157 if (match(Op1, m_Undef()))
1161 if (match(Op0, m_Undef()))
1162 return Constant::getNullValue(Op0->getType());
1164 // 0 % X -> 0, we don't need to preserve faults!
1165 if (match(Op0, m_Zero()))
1168 // X % 0 -> undef, we don't need to preserve faults!
1169 if (match(Op1, m_Zero()))
1170 return UndefValue::get(Op0->getType());
1173 if (match(Op1, m_One()))
1174 return Constant::getNullValue(Op0->getType());
1176 if (Op0->getType()->isIntegerTy(1))
1177 // It can't be remainder by zero, hence it must be remainder by one.
1178 return Constant::getNullValue(Op0->getType());
1182 return Constant::getNullValue(Op0->getType());
1184 // (X % Y) % Y -> X % Y
1185 if ((Opcode == Instruction::SRem &&
1186 match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1187 (Opcode == Instruction::URem &&
1188 match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1191 // If the operation is with the result of a select instruction, check whether
1192 // operating on either branch of the select always yields the same value.
1193 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1194 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1197 // If the operation is with the result of a phi instruction, check whether
1198 // operating on all incoming values of the phi always yields the same value.
1199 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1200 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1206 /// SimplifySRemInst - Given operands for an SRem, see if we can
1207 /// fold the result. If not, this returns null.
1208 static Value *SimplifySRemInst(Value *Op0, Value *Op1, const Query &Q,
1209 unsigned MaxRecurse) {
1210 if (Value *V = SimplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse))
1216 Value *llvm::SimplifySRemInst(Value *Op0, Value *Op1, const DataLayout *DL,
1217 const TargetLibraryInfo *TLI,
1218 const DominatorTree *DT,
1219 AssumptionTracker *AT,
1220 const Instruction *CxtI) {
1221 return ::SimplifySRemInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1225 /// SimplifyURemInst - Given operands for a URem, see if we can
1226 /// fold the result. If not, this returns null.
1227 static Value *SimplifyURemInst(Value *Op0, Value *Op1, const Query &Q,
1228 unsigned MaxRecurse) {
1229 if (Value *V = SimplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse))
1235 Value *llvm::SimplifyURemInst(Value *Op0, Value *Op1, const DataLayout *DL,
1236 const TargetLibraryInfo *TLI,
1237 const DominatorTree *DT,
1238 AssumptionTracker *AT,
1239 const Instruction *CxtI) {
1240 return ::SimplifyURemInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1244 static Value *SimplifyFRemInst(Value *Op0, Value *Op1, const Query &,
1246 // undef % X -> undef (the undef could be a snan).
1247 if (match(Op0, m_Undef()))
1250 // X % undef -> undef
1251 if (match(Op1, m_Undef()))
1257 Value *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, const DataLayout *DL,
1258 const TargetLibraryInfo *TLI,
1259 const DominatorTree *DT,
1260 AssumptionTracker *AT,
1261 const Instruction *CxtI) {
1262 return ::SimplifyFRemInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1266 /// isUndefShift - Returns true if a shift by \c Amount always yields undef.
1267 static bool isUndefShift(Value *Amount) {
1268 Constant *C = dyn_cast<Constant>(Amount);
1272 // X shift by undef -> undef because it may shift by the bitwidth.
1273 if (isa<UndefValue>(C))
1276 // Shifting by the bitwidth or more is undefined.
1277 if (ConstantInt *CI = dyn_cast<ConstantInt>(C))
1278 if (CI->getValue().getLimitedValue() >=
1279 CI->getType()->getScalarSizeInBits())
1282 // If all lanes of a vector shift are undefined the whole shift is.
1283 if (isa<ConstantVector>(C) || isa<ConstantDataVector>(C)) {
1284 for (unsigned I = 0, E = C->getType()->getVectorNumElements(); I != E; ++I)
1285 if (!isUndefShift(C->getAggregateElement(I)))
1293 /// SimplifyShift - Given operands for an Shl, LShr or AShr, see if we can
1294 /// fold the result. If not, this returns null.
1295 static Value *SimplifyShift(unsigned Opcode, Value *Op0, Value *Op1,
1296 const Query &Q, unsigned MaxRecurse) {
1297 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1298 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1299 Constant *Ops[] = { C0, C1 };
1300 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.DL, Q.TLI);
1304 // 0 shift by X -> 0
1305 if (match(Op0, m_Zero()))
1308 // X shift by 0 -> X
1309 if (match(Op1, m_Zero()))
1312 // Fold undefined shifts.
1313 if (isUndefShift(Op1))
1314 return UndefValue::get(Op0->getType());
1316 // If the operation is with the result of a select instruction, check whether
1317 // operating on either branch of the select always yields the same value.
1318 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1319 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1322 // If the operation is with the result of a phi instruction, check whether
1323 // operating on all incoming values of the phi always yields the same value.
1324 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1325 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1331 /// \brief Given operands for an Shl, LShr or AShr, see if we can
1332 /// fold the result. If not, this returns null.
1333 static Value *SimplifyRightShift(unsigned Opcode, Value *Op0, Value *Op1,
1334 bool isExact, const Query &Q,
1335 unsigned MaxRecurse) {
1336 if (Value *V = SimplifyShift(Opcode, Op0, Op1, Q, MaxRecurse))
1341 return Constant::getNullValue(Op0->getType());
1343 // The low bit cannot be shifted out of an exact shift if it is set.
1345 unsigned BitWidth = Op0->getType()->getScalarSizeInBits();
1346 APInt Op0KnownZero(BitWidth, 0);
1347 APInt Op0KnownOne(BitWidth, 0);
1348 computeKnownBits(Op0, Op0KnownZero, Op0KnownOne, Q.DL, /*Depth=*/0, Q.AT, Q.CxtI,
1357 /// SimplifyShlInst - Given operands for an Shl, see if we can
1358 /// fold the result. If not, this returns null.
1359 static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1360 const Query &Q, unsigned MaxRecurse) {
1361 if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse))
1365 if (match(Op0, m_Undef()))
1366 return Constant::getNullValue(Op0->getType());
1368 // (X >> A) << A -> X
1370 if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
1375 Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1376 const DataLayout *DL, const TargetLibraryInfo *TLI,
1377 const DominatorTree *DT, AssumptionTracker *AT,
1378 const Instruction *CxtI) {
1379 return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Query (DL, TLI, DT, AT, CxtI),
1383 /// SimplifyLShrInst - Given operands for an LShr, see if we can
1384 /// fold the result. If not, this returns null.
1385 static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1386 const Query &Q, unsigned MaxRecurse) {
1387 if (Value *V = SimplifyRightShift(Instruction::LShr, Op0, Op1, isExact, Q,
1392 if (match(Op0, m_Undef()))
1393 return Constant::getNullValue(Op0->getType());
1395 // (X << A) >> A -> X
1397 if (match(Op0, m_NUWShl(m_Value(X), m_Specific(Op1))))
1403 Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1404 const DataLayout *DL,
1405 const TargetLibraryInfo *TLI,
1406 const DominatorTree *DT,
1407 AssumptionTracker *AT,
1408 const Instruction *CxtI) {
1409 return ::SimplifyLShrInst(Op0, Op1, isExact, Query (DL, TLI, DT, AT, CxtI),
1413 /// SimplifyAShrInst - Given operands for an AShr, see if we can
1414 /// fold the result. If not, this returns null.
1415 static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1416 const Query &Q, unsigned MaxRecurse) {
1417 if (Value *V = SimplifyRightShift(Instruction::AShr, Op0, Op1, isExact, Q,
1421 // all ones >>a X -> all ones
1422 if (match(Op0, m_AllOnes()))
1425 // undef >>a X -> all ones
1426 if (match(Op0, m_Undef()))
1427 return Constant::getAllOnesValue(Op0->getType());
1429 // (X << A) >> A -> X
1431 if (match(Op0, m_NSWShl(m_Value(X), m_Specific(Op1))))
1434 // Arithmetic shifting an all-sign-bit value is a no-op.
1435 unsigned NumSignBits = ComputeNumSignBits(Op0, Q.DL, 0, Q.AT, Q.CxtI, Q.DT);
1436 if (NumSignBits == Op0->getType()->getScalarSizeInBits())
1442 Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1443 const DataLayout *DL,
1444 const TargetLibraryInfo *TLI,
1445 const DominatorTree *DT,
1446 AssumptionTracker *AT,
1447 const Instruction *CxtI) {
1448 return ::SimplifyAShrInst(Op0, Op1, isExact, Query (DL, TLI, DT, AT, CxtI),
1452 // Simplify (and (icmp ...) (icmp ...)) to true when we can tell that the range
1453 // of possible values cannot be satisfied.
1454 static Value *SimplifyAndOfICmps(ICmpInst *Op0, ICmpInst *Op1) {
1455 ICmpInst::Predicate Pred0, Pred1;
1456 ConstantInt *CI1, *CI2;
1458 if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_ConstantInt(CI1)),
1459 m_ConstantInt(CI2))))
1462 if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Specific(CI1))))
1465 Type *ITy = Op0->getType();
1467 auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1468 bool isNSW = AddInst->hasNoSignedWrap();
1469 bool isNUW = AddInst->hasNoUnsignedWrap();
1471 const APInt &CI1V = CI1->getValue();
1472 const APInt &CI2V = CI2->getValue();
1473 const APInt Delta = CI2V - CI1V;
1474 if (CI1V.isStrictlyPositive()) {
1476 if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_SGT)
1477 return getFalse(ITy);
1478 if (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1479 return getFalse(ITy);
1482 if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_SGT)
1483 return getFalse(ITy);
1484 if (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1485 return getFalse(ITy);
1488 if (CI1V.getBoolValue() && isNUW) {
1490 if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT)
1491 return getFalse(ITy);
1493 if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGT)
1494 return getFalse(ITy);
1500 /// SimplifyAndInst - Given operands for an And, see if we can
1501 /// fold the result. If not, this returns null.
1502 static Value *SimplifyAndInst(Value *Op0, Value *Op1, const Query &Q,
1503 unsigned MaxRecurse) {
1504 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1505 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1506 Constant *Ops[] = { CLHS, CRHS };
1507 return ConstantFoldInstOperands(Instruction::And, CLHS->getType(),
1511 // Canonicalize the constant to the RHS.
1512 std::swap(Op0, Op1);
1516 if (match(Op1, m_Undef()))
1517 return Constant::getNullValue(Op0->getType());
1524 if (match(Op1, m_Zero()))
1528 if (match(Op1, m_AllOnes()))
1531 // A & ~A = ~A & A = 0
1532 if (match(Op0, m_Not(m_Specific(Op1))) ||
1533 match(Op1, m_Not(m_Specific(Op0))))
1534 return Constant::getNullValue(Op0->getType());
1537 Value *A = nullptr, *B = nullptr;
1538 if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
1539 (A == Op1 || B == Op1))
1543 if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
1544 (A == Op0 || B == Op0))
1547 // A & (-A) = A if A is a power of two or zero.
1548 if (match(Op0, m_Neg(m_Specific(Op1))) ||
1549 match(Op1, m_Neg(m_Specific(Op0)))) {
1550 if (isKnownToBeAPowerOfTwo(Op0, /*OrZero*/true, 0, Q.AT, Q.CxtI, Q.DT))
1552 if (isKnownToBeAPowerOfTwo(Op1, /*OrZero*/true, 0, Q.AT, Q.CxtI, Q.DT))
1556 if (auto *ICILHS = dyn_cast<ICmpInst>(Op0)) {
1557 if (auto *ICIRHS = dyn_cast<ICmpInst>(Op1)) {
1558 if (Value *V = SimplifyAndOfICmps(ICILHS, ICIRHS))
1560 if (Value *V = SimplifyAndOfICmps(ICIRHS, ICILHS))
1565 // Try some generic simplifications for associative operations.
1566 if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
1570 // And distributes over Or. Try some generic simplifications based on this.
1571 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1575 // And distributes over Xor. Try some generic simplifications based on this.
1576 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
1580 // If the operation is with the result of a select instruction, check whether
1581 // operating on either branch of the select always yields the same value.
1582 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1583 if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
1587 // If the operation is with the result of a phi instruction, check whether
1588 // operating on all incoming values of the phi always yields the same value.
1589 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1590 if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
1597 Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const DataLayout *DL,
1598 const TargetLibraryInfo *TLI,
1599 const DominatorTree *DT, AssumptionTracker *AT,
1600 const Instruction *CxtI) {
1601 return ::SimplifyAndInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1605 // Simplify (or (icmp ...) (icmp ...)) to true when we can tell that the union
1606 // contains all possible values.
1607 static Value *SimplifyOrOfICmps(ICmpInst *Op0, ICmpInst *Op1) {
1608 ICmpInst::Predicate Pred0, Pred1;
1609 ConstantInt *CI1, *CI2;
1611 if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_ConstantInt(CI1)),
1612 m_ConstantInt(CI2))))
1615 if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Specific(CI1))))
1618 Type *ITy = Op0->getType();
1620 auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1621 bool isNSW = AddInst->hasNoSignedWrap();
1622 bool isNUW = AddInst->hasNoUnsignedWrap();
1624 const APInt &CI1V = CI1->getValue();
1625 const APInt &CI2V = CI2->getValue();
1626 const APInt Delta = CI2V - CI1V;
1627 if (CI1V.isStrictlyPositive()) {
1629 if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_SLE)
1630 return getTrue(ITy);
1631 if (Pred0 == ICmpInst::ICMP_SGE && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1632 return getTrue(ITy);
1635 if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_SLE)
1636 return getTrue(ITy);
1637 if (Pred0 == ICmpInst::ICMP_SGT && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1638 return getTrue(ITy);
1641 if (CI1V.getBoolValue() && isNUW) {
1643 if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_ULE)
1644 return getTrue(ITy);
1646 if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_ULE)
1647 return getTrue(ITy);
1653 /// SimplifyOrInst - Given operands for an Or, see if we can
1654 /// fold the result. If not, this returns null.
1655 static Value *SimplifyOrInst(Value *Op0, Value *Op1, const Query &Q,
1656 unsigned MaxRecurse) {
1657 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1658 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1659 Constant *Ops[] = { CLHS, CRHS };
1660 return ConstantFoldInstOperands(Instruction::Or, CLHS->getType(),
1664 // Canonicalize the constant to the RHS.
1665 std::swap(Op0, Op1);
1669 if (match(Op1, m_Undef()))
1670 return Constant::getAllOnesValue(Op0->getType());
1677 if (match(Op1, m_Zero()))
1681 if (match(Op1, m_AllOnes()))
1684 // A | ~A = ~A | A = -1
1685 if (match(Op0, m_Not(m_Specific(Op1))) ||
1686 match(Op1, m_Not(m_Specific(Op0))))
1687 return Constant::getAllOnesValue(Op0->getType());
1690 Value *A = nullptr, *B = nullptr;
1691 if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
1692 (A == Op1 || B == Op1))
1696 if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
1697 (A == Op0 || B == Op0))
1700 // ~(A & ?) | A = -1
1701 if (match(Op0, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1702 (A == Op1 || B == Op1))
1703 return Constant::getAllOnesValue(Op1->getType());
1705 // A | ~(A & ?) = -1
1706 if (match(Op1, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1707 (A == Op0 || B == Op0))
1708 return Constant::getAllOnesValue(Op0->getType());
1710 if (auto *ICILHS = dyn_cast<ICmpInst>(Op0)) {
1711 if (auto *ICIRHS = dyn_cast<ICmpInst>(Op1)) {
1712 if (Value *V = SimplifyOrOfICmps(ICILHS, ICIRHS))
1714 if (Value *V = SimplifyOrOfICmps(ICIRHS, ICILHS))
1719 // Try some generic simplifications for associative operations.
1720 if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
1724 // Or distributes over And. Try some generic simplifications based on this.
1725 if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
1729 // If the operation is with the result of a select instruction, check whether
1730 // operating on either branch of the select always yields the same value.
1731 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1732 if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
1737 Value *C = nullptr, *D = nullptr;
1738 if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
1739 match(Op1, m_And(m_Value(B), m_Value(D)))) {
1740 ConstantInt *C1 = dyn_cast<ConstantInt>(C);
1741 ConstantInt *C2 = dyn_cast<ConstantInt>(D);
1742 if (C1 && C2 && (C1->getValue() == ~C2->getValue())) {
1743 // (A & C1)|(B & C2)
1744 // If we have: ((V + N) & C1) | (V & C2)
1745 // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
1746 // replace with V+N.
1748 if ((C2->getValue() & (C2->getValue() + 1)) == 0 && // C2 == 0+1+
1749 match(A, m_Add(m_Value(V1), m_Value(V2)))) {
1750 // Add commutes, try both ways.
1751 if (V1 == B && MaskedValueIsZero(V2, C2->getValue(), Q.DL,
1752 0, Q.AT, Q.CxtI, Q.DT))
1754 if (V2 == B && MaskedValueIsZero(V1, C2->getValue(), Q.DL,
1755 0, Q.AT, Q.CxtI, Q.DT))
1758 // Or commutes, try both ways.
1759 if ((C1->getValue() & (C1->getValue() + 1)) == 0 &&
1760 match(B, m_Add(m_Value(V1), m_Value(V2)))) {
1761 // Add commutes, try both ways.
1762 if (V1 == A && MaskedValueIsZero(V2, C1->getValue(), Q.DL,
1763 0, Q.AT, Q.CxtI, Q.DT))
1765 if (V2 == A && MaskedValueIsZero(V1, C1->getValue(), Q.DL,
1766 0, Q.AT, Q.CxtI, Q.DT))
1772 // If the operation is with the result of a phi instruction, check whether
1773 // operating on all incoming values of the phi always yields the same value.
1774 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1775 if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
1781 Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const DataLayout *DL,
1782 const TargetLibraryInfo *TLI,
1783 const DominatorTree *DT, AssumptionTracker *AT,
1784 const Instruction *CxtI) {
1785 return ::SimplifyOrInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1789 /// SimplifyXorInst - Given operands for a Xor, see if we can
1790 /// fold the result. If not, this returns null.
1791 static Value *SimplifyXorInst(Value *Op0, Value *Op1, const Query &Q,
1792 unsigned MaxRecurse) {
1793 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1794 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1795 Constant *Ops[] = { CLHS, CRHS };
1796 return ConstantFoldInstOperands(Instruction::Xor, CLHS->getType(),
1800 // Canonicalize the constant to the RHS.
1801 std::swap(Op0, Op1);
1804 // A ^ undef -> undef
1805 if (match(Op1, m_Undef()))
1809 if (match(Op1, m_Zero()))
1814 return Constant::getNullValue(Op0->getType());
1816 // A ^ ~A = ~A ^ A = -1
1817 if (match(Op0, m_Not(m_Specific(Op1))) ||
1818 match(Op1, m_Not(m_Specific(Op0))))
1819 return Constant::getAllOnesValue(Op0->getType());
1821 // Try some generic simplifications for associative operations.
1822 if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
1826 // Threading Xor over selects and phi nodes is pointless, so don't bother.
1827 // Threading over the select in "A ^ select(cond, B, C)" means evaluating
1828 // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
1829 // only if B and C are equal. If B and C are equal then (since we assume
1830 // that operands have already been simplified) "select(cond, B, C)" should
1831 // have been simplified to the common value of B and C already. Analysing
1832 // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
1833 // for threading over phi nodes.
1838 Value *llvm::SimplifyXorInst(Value *Op0, Value *Op1, const DataLayout *DL,
1839 const TargetLibraryInfo *TLI,
1840 const DominatorTree *DT, AssumptionTracker *AT,
1841 const Instruction *CxtI) {
1842 return ::SimplifyXorInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1846 static Type *GetCompareTy(Value *Op) {
1847 return CmpInst::makeCmpResultType(Op->getType());
1850 /// ExtractEquivalentCondition - Rummage around inside V looking for something
1851 /// equivalent to the comparison "LHS Pred RHS". Return such a value if found,
1852 /// otherwise return null. Helper function for analyzing max/min idioms.
1853 static Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred,
1854 Value *LHS, Value *RHS) {
1855 SelectInst *SI = dyn_cast<SelectInst>(V);
1858 CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
1861 Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
1862 if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
1864 if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
1865 LHS == CmpRHS && RHS == CmpLHS)
1870 // A significant optimization not implemented here is assuming that alloca
1871 // addresses are not equal to incoming argument values. They don't *alias*,
1872 // as we say, but that doesn't mean they aren't equal, so we take a
1873 // conservative approach.
1875 // This is inspired in part by C++11 5.10p1:
1876 // "Two pointers of the same type compare equal if and only if they are both
1877 // null, both point to the same function, or both represent the same
1880 // This is pretty permissive.
1882 // It's also partly due to C11 6.5.9p6:
1883 // "Two pointers compare equal if and only if both are null pointers, both are
1884 // pointers to the same object (including a pointer to an object and a
1885 // subobject at its beginning) or function, both are pointers to one past the
1886 // last element of the same array object, or one is a pointer to one past the
1887 // end of one array object and the other is a pointer to the start of a
1888 // different array object that happens to immediately follow the first array
1889 // object in the address space.)
1891 // C11's version is more restrictive, however there's no reason why an argument
1892 // couldn't be a one-past-the-end value for a stack object in the caller and be
1893 // equal to the beginning of a stack object in the callee.
1895 // If the C and C++ standards are ever made sufficiently restrictive in this
1896 // area, it may be possible to update LLVM's semantics accordingly and reinstate
1897 // this optimization.
1898 static Constant *computePointerICmp(const DataLayout *DL,
1899 const TargetLibraryInfo *TLI,
1900 CmpInst::Predicate Pred,
1901 Value *LHS, Value *RHS) {
1902 // First, skip past any trivial no-ops.
1903 LHS = LHS->stripPointerCasts();
1904 RHS = RHS->stripPointerCasts();
1906 // A non-null pointer is not equal to a null pointer.
1907 if (llvm::isKnownNonNull(LHS, TLI) && isa<ConstantPointerNull>(RHS) &&
1908 (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE))
1909 return ConstantInt::get(GetCompareTy(LHS),
1910 !CmpInst::isTrueWhenEqual(Pred));
1912 // We can only fold certain predicates on pointer comparisons.
1917 // Equality comaprisons are easy to fold.
1918 case CmpInst::ICMP_EQ:
1919 case CmpInst::ICMP_NE:
1922 // We can only handle unsigned relational comparisons because 'inbounds' on
1923 // a GEP only protects against unsigned wrapping.
1924 case CmpInst::ICMP_UGT:
1925 case CmpInst::ICMP_UGE:
1926 case CmpInst::ICMP_ULT:
1927 case CmpInst::ICMP_ULE:
1928 // However, we have to switch them to their signed variants to handle
1929 // negative indices from the base pointer.
1930 Pred = ICmpInst::getSignedPredicate(Pred);
1934 // Strip off any constant offsets so that we can reason about them.
1935 // It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets
1936 // here and compare base addresses like AliasAnalysis does, however there are
1937 // numerous hazards. AliasAnalysis and its utilities rely on special rules
1938 // governing loads and stores which don't apply to icmps. Also, AliasAnalysis
1939 // doesn't need to guarantee pointer inequality when it says NoAlias.
1940 Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
1941 Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
1943 // If LHS and RHS are related via constant offsets to the same base
1944 // value, we can replace it with an icmp which just compares the offsets.
1946 return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset);
1948 // Various optimizations for (in)equality comparisons.
1949 if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE) {
1950 // Different non-empty allocations that exist at the same time have
1951 // different addresses (if the program can tell). Global variables always
1952 // exist, so they always exist during the lifetime of each other and all
1953 // allocas. Two different allocas usually have different addresses...
1955 // However, if there's an @llvm.stackrestore dynamically in between two
1956 // allocas, they may have the same address. It's tempting to reduce the
1957 // scope of the problem by only looking at *static* allocas here. That would
1958 // cover the majority of allocas while significantly reducing the likelihood
1959 // of having an @llvm.stackrestore pop up in the middle. However, it's not
1960 // actually impossible for an @llvm.stackrestore to pop up in the middle of
1961 // an entry block. Also, if we have a block that's not attached to a
1962 // function, we can't tell if it's "static" under the current definition.
1963 // Theoretically, this problem could be fixed by creating a new kind of
1964 // instruction kind specifically for static allocas. Such a new instruction
1965 // could be required to be at the top of the entry block, thus preventing it
1966 // from being subject to a @llvm.stackrestore. Instcombine could even
1967 // convert regular allocas into these special allocas. It'd be nifty.
1968 // However, until then, this problem remains open.
1970 // So, we'll assume that two non-empty allocas have different addresses
1973 // With all that, if the offsets are within the bounds of their allocations
1974 // (and not one-past-the-end! so we can't use inbounds!), and their
1975 // allocations aren't the same, the pointers are not equal.
1977 // Note that it's not necessary to check for LHS being a global variable
1978 // address, due to canonicalization and constant folding.
1979 if (isa<AllocaInst>(LHS) &&
1980 (isa<AllocaInst>(RHS) || isa<GlobalVariable>(RHS))) {
1981 ConstantInt *LHSOffsetCI = dyn_cast<ConstantInt>(LHSOffset);
1982 ConstantInt *RHSOffsetCI = dyn_cast<ConstantInt>(RHSOffset);
1983 uint64_t LHSSize, RHSSize;
1984 if (LHSOffsetCI && RHSOffsetCI &&
1985 getObjectSize(LHS, LHSSize, DL, TLI) &&
1986 getObjectSize(RHS, RHSSize, DL, TLI)) {
1987 const APInt &LHSOffsetValue = LHSOffsetCI->getValue();
1988 const APInt &RHSOffsetValue = RHSOffsetCI->getValue();
1989 if (!LHSOffsetValue.isNegative() &&
1990 !RHSOffsetValue.isNegative() &&
1991 LHSOffsetValue.ult(LHSSize) &&
1992 RHSOffsetValue.ult(RHSSize)) {
1993 return ConstantInt::get(GetCompareTy(LHS),
1994 !CmpInst::isTrueWhenEqual(Pred));
1998 // Repeat the above check but this time without depending on DataLayout
1999 // or being able to compute a precise size.
2000 if (!cast<PointerType>(LHS->getType())->isEmptyTy() &&
2001 !cast<PointerType>(RHS->getType())->isEmptyTy() &&
2002 LHSOffset->isNullValue() &&
2003 RHSOffset->isNullValue())
2004 return ConstantInt::get(GetCompareTy(LHS),
2005 !CmpInst::isTrueWhenEqual(Pred));
2008 // Even if an non-inbounds GEP occurs along the path we can still optimize
2009 // equality comparisons concerning the result. We avoid walking the whole
2010 // chain again by starting where the last calls to
2011 // stripAndComputeConstantOffsets left off and accumulate the offsets.
2012 Constant *LHSNoBound = stripAndComputeConstantOffsets(DL, LHS, true);
2013 Constant *RHSNoBound = stripAndComputeConstantOffsets(DL, RHS, true);
2015 return ConstantExpr::getICmp(Pred,
2016 ConstantExpr::getAdd(LHSOffset, LHSNoBound),
2017 ConstantExpr::getAdd(RHSOffset, RHSNoBound));
2024 /// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
2025 /// fold the result. If not, this returns null.
2026 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2027 const Query &Q, unsigned MaxRecurse) {
2028 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
2029 assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
2031 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
2032 if (Constant *CRHS = dyn_cast<Constant>(RHS))
2033 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
2035 // If we have a constant, make sure it is on the RHS.
2036 std::swap(LHS, RHS);
2037 Pred = CmpInst::getSwappedPredicate(Pred);
2040 Type *ITy = GetCompareTy(LHS); // The return type.
2041 Type *OpTy = LHS->getType(); // The operand type.
2043 // icmp X, X -> true/false
2044 // X icmp undef -> true/false. For example, icmp ugt %X, undef -> false
2045 // because X could be 0.
2046 if (LHS == RHS || isa<UndefValue>(RHS))
2047 return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
2049 // Special case logic when the operands have i1 type.
2050 if (OpTy->getScalarType()->isIntegerTy(1)) {
2053 case ICmpInst::ICMP_EQ:
2055 if (match(RHS, m_One()))
2058 case ICmpInst::ICMP_NE:
2060 if (match(RHS, m_Zero()))
2063 case ICmpInst::ICMP_UGT:
2065 if (match(RHS, m_Zero()))
2068 case ICmpInst::ICMP_UGE:
2070 if (match(RHS, m_One()))
2073 case ICmpInst::ICMP_SLT:
2075 if (match(RHS, m_Zero()))
2078 case ICmpInst::ICMP_SLE:
2080 if (match(RHS, m_One()))
2086 // If we are comparing with zero then try hard since this is a common case.
2087 if (match(RHS, m_Zero())) {
2088 bool LHSKnownNonNegative, LHSKnownNegative;
2090 default: llvm_unreachable("Unknown ICmp predicate!");
2091 case ICmpInst::ICMP_ULT:
2092 return getFalse(ITy);
2093 case ICmpInst::ICMP_UGE:
2094 return getTrue(ITy);
2095 case ICmpInst::ICMP_EQ:
2096 case ICmpInst::ICMP_ULE:
2097 if (isKnownNonZero(LHS, Q.DL, 0, Q.AT, Q.CxtI, Q.DT))
2098 return getFalse(ITy);
2100 case ICmpInst::ICMP_NE:
2101 case ICmpInst::ICMP_UGT:
2102 if (isKnownNonZero(LHS, Q.DL, 0, Q.AT, Q.CxtI, Q.DT))
2103 return getTrue(ITy);
2105 case ICmpInst::ICMP_SLT:
2106 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL,
2107 0, Q.AT, Q.CxtI, Q.DT);
2108 if (LHSKnownNegative)
2109 return getTrue(ITy);
2110 if (LHSKnownNonNegative)
2111 return getFalse(ITy);
2113 case ICmpInst::ICMP_SLE:
2114 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL,
2115 0, Q.AT, Q.CxtI, Q.DT);
2116 if (LHSKnownNegative)
2117 return getTrue(ITy);
2118 if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.DL,
2119 0, Q.AT, Q.CxtI, Q.DT))
2120 return getFalse(ITy);
2122 case ICmpInst::ICMP_SGE:
2123 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL,
2124 0, Q.AT, Q.CxtI, Q.DT);
2125 if (LHSKnownNegative)
2126 return getFalse(ITy);
2127 if (LHSKnownNonNegative)
2128 return getTrue(ITy);
2130 case ICmpInst::ICMP_SGT:
2131 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL,
2132 0, Q.AT, Q.CxtI, Q.DT);
2133 if (LHSKnownNegative)
2134 return getFalse(ITy);
2135 if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.DL,
2136 0, Q.AT, Q.CxtI, Q.DT))
2137 return getTrue(ITy);
2142 // See if we are doing a comparison with a constant integer.
2143 if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2144 // Rule out tautological comparisons (eg., ult 0 or uge 0).
2145 ConstantRange RHS_CR = ICmpInst::makeConstantRange(Pred, CI->getValue());
2146 if (RHS_CR.isEmptySet())
2147 return ConstantInt::getFalse(CI->getContext());
2148 if (RHS_CR.isFullSet())
2149 return ConstantInt::getTrue(CI->getContext());
2151 // Many binary operators with constant RHS have easy to compute constant
2152 // range. Use them to check whether the comparison is a tautology.
2153 unsigned Width = CI->getBitWidth();
2154 APInt Lower = APInt(Width, 0);
2155 APInt Upper = APInt(Width, 0);
2157 if (match(LHS, m_URem(m_Value(), m_ConstantInt(CI2)))) {
2158 // 'urem x, CI2' produces [0, CI2).
2159 Upper = CI2->getValue();
2160 } else if (match(LHS, m_SRem(m_Value(), m_ConstantInt(CI2)))) {
2161 // 'srem x, CI2' produces (-|CI2|, |CI2|).
2162 Upper = CI2->getValue().abs();
2163 Lower = (-Upper) + 1;
2164 } else if (match(LHS, m_UDiv(m_ConstantInt(CI2), m_Value()))) {
2165 // 'udiv CI2, x' produces [0, CI2].
2166 Upper = CI2->getValue() + 1;
2167 } else if (match(LHS, m_UDiv(m_Value(), m_ConstantInt(CI2)))) {
2168 // 'udiv x, CI2' produces [0, UINT_MAX / CI2].
2169 APInt NegOne = APInt::getAllOnesValue(Width);
2171 Upper = NegOne.udiv(CI2->getValue()) + 1;
2172 } else if (match(LHS, m_SDiv(m_ConstantInt(CI2), m_Value()))) {
2173 if (CI2->isMinSignedValue()) {
2174 // 'sdiv INT_MIN, x' produces [INT_MIN, INT_MIN / -2].
2175 Lower = CI2->getValue();
2176 Upper = Lower.lshr(1) + 1;
2178 // 'sdiv CI2, x' produces [-|CI2|, |CI2|].
2179 Upper = CI2->getValue().abs() + 1;
2180 Lower = (-Upper) + 1;
2182 } else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) {
2183 APInt IntMin = APInt::getSignedMinValue(Width);
2184 APInt IntMax = APInt::getSignedMaxValue(Width);
2185 APInt Val = CI2->getValue();
2186 if (Val.isAllOnesValue()) {
2187 // 'sdiv x, -1' produces [INT_MIN + 1, INT_MAX]
2188 // where CI2 != -1 and CI2 != 0 and CI2 != 1
2191 } else if (Val.countLeadingZeros() < Width - 1) {
2192 // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2]
2193 // where CI2 != -1 and CI2 != 0 and CI2 != 1
2194 Lower = IntMin.sdiv(Val);
2195 Upper = IntMax.sdiv(Val);
2196 if (Lower.sgt(Upper))
2197 std::swap(Lower, Upper);
2199 assert(Upper != Lower && "Upper part of range has wrapped!");
2201 } else if (match(LHS, m_NUWShl(m_ConstantInt(CI2), m_Value()))) {
2202 // 'shl nuw CI2, x' produces [CI2, CI2 << CLZ(CI2)]
2203 Lower = CI2->getValue();
2204 Upper = Lower.shl(Lower.countLeadingZeros()) + 1;
2205 } else if (match(LHS, m_NSWShl(m_ConstantInt(CI2), m_Value()))) {
2206 if (CI2->isNegative()) {
2207 // 'shl nsw CI2, x' produces [CI2 << CLO(CI2)-1, CI2]
2208 unsigned ShiftAmount = CI2->getValue().countLeadingOnes() - 1;
2209 Lower = CI2->getValue().shl(ShiftAmount);
2210 Upper = CI2->getValue() + 1;
2212 // 'shl nsw CI2, x' produces [CI2, CI2 << CLZ(CI2)-1]
2213 unsigned ShiftAmount = CI2->getValue().countLeadingZeros() - 1;
2214 Lower = CI2->getValue();
2215 Upper = CI2->getValue().shl(ShiftAmount) + 1;
2217 } else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) {
2218 // 'lshr x, CI2' produces [0, UINT_MAX >> CI2].
2219 APInt NegOne = APInt::getAllOnesValue(Width);
2220 if (CI2->getValue().ult(Width))
2221 Upper = NegOne.lshr(CI2->getValue()) + 1;
2222 } else if (match(LHS, m_LShr(m_ConstantInt(CI2), m_Value()))) {
2223 // 'lshr CI2, x' produces [CI2 >> (Width-1), CI2].
2224 unsigned ShiftAmount = Width - 1;
2225 if (!CI2->isZero() && cast<BinaryOperator>(LHS)->isExact())
2226 ShiftAmount = CI2->getValue().countTrailingZeros();
2227 Lower = CI2->getValue().lshr(ShiftAmount);
2228 Upper = CI2->getValue() + 1;
2229 } else if (match(LHS, m_AShr(m_Value(), m_ConstantInt(CI2)))) {
2230 // 'ashr x, CI2' produces [INT_MIN >> CI2, INT_MAX >> CI2].
2231 APInt IntMin = APInt::getSignedMinValue(Width);
2232 APInt IntMax = APInt::getSignedMaxValue(Width);
2233 if (CI2->getValue().ult(Width)) {
2234 Lower = IntMin.ashr(CI2->getValue());
2235 Upper = IntMax.ashr(CI2->getValue()) + 1;
2237 } else if (match(LHS, m_AShr(m_ConstantInt(CI2), m_Value()))) {
2238 unsigned ShiftAmount = Width - 1;
2239 if (!CI2->isZero() && cast<BinaryOperator>(LHS)->isExact())
2240 ShiftAmount = CI2->getValue().countTrailingZeros();
2241 if (CI2->isNegative()) {
2242 // 'ashr CI2, x' produces [CI2, CI2 >> (Width-1)]
2243 Lower = CI2->getValue();
2244 Upper = CI2->getValue().ashr(ShiftAmount) + 1;
2246 // 'ashr CI2, x' produces [CI2 >> (Width-1), CI2]
2247 Lower = CI2->getValue().ashr(ShiftAmount);
2248 Upper = CI2->getValue() + 1;
2250 } else if (match(LHS, m_Or(m_Value(), m_ConstantInt(CI2)))) {
2251 // 'or x, CI2' produces [CI2, UINT_MAX].
2252 Lower = CI2->getValue();
2253 } else if (match(LHS, m_And(m_Value(), m_ConstantInt(CI2)))) {
2254 // 'and x, CI2' produces [0, CI2].
2255 Upper = CI2->getValue() + 1;
2257 if (Lower != Upper) {
2258 ConstantRange LHS_CR = ConstantRange(Lower, Upper);
2259 if (RHS_CR.contains(LHS_CR))
2260 return ConstantInt::getTrue(RHS->getContext());
2261 if (RHS_CR.inverse().contains(LHS_CR))
2262 return ConstantInt::getFalse(RHS->getContext());
2266 // Compare of cast, for example (zext X) != 0 -> X != 0
2267 if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
2268 Instruction *LI = cast<CastInst>(LHS);
2269 Value *SrcOp = LI->getOperand(0);
2270 Type *SrcTy = SrcOp->getType();
2271 Type *DstTy = LI->getType();
2273 // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
2274 // if the integer type is the same size as the pointer type.
2275 if (MaxRecurse && Q.DL && isa<PtrToIntInst>(LI) &&
2276 Q.DL->getTypeSizeInBits(SrcTy) == DstTy->getPrimitiveSizeInBits()) {
2277 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
2278 // Transfer the cast to the constant.
2279 if (Value *V = SimplifyICmpInst(Pred, SrcOp,
2280 ConstantExpr::getIntToPtr(RHSC, SrcTy),
2283 } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
2284 if (RI->getOperand(0)->getType() == SrcTy)
2285 // Compare without the cast.
2286 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2292 if (isa<ZExtInst>(LHS)) {
2293 // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
2295 if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
2296 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2297 // Compare X and Y. Note that signed predicates become unsigned.
2298 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
2299 SrcOp, RI->getOperand(0), Q,
2303 // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
2304 // too. If not, then try to deduce the result of the comparison.
2305 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2306 // Compute the constant that would happen if we truncated to SrcTy then
2307 // reextended to DstTy.
2308 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2309 Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
2311 // If the re-extended constant didn't change then this is effectively
2312 // also a case of comparing two zero-extended values.
2313 if (RExt == CI && MaxRecurse)
2314 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
2315 SrcOp, Trunc, Q, MaxRecurse-1))
2318 // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
2319 // there. Use this to work out the result of the comparison.
2322 default: llvm_unreachable("Unknown ICmp predicate!");
2324 case ICmpInst::ICMP_EQ:
2325 case ICmpInst::ICMP_UGT:
2326 case ICmpInst::ICMP_UGE:
2327 return ConstantInt::getFalse(CI->getContext());
2329 case ICmpInst::ICMP_NE:
2330 case ICmpInst::ICMP_ULT:
2331 case ICmpInst::ICMP_ULE:
2332 return ConstantInt::getTrue(CI->getContext());
2334 // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
2335 // is non-negative then LHS <s RHS.
2336 case ICmpInst::ICMP_SGT:
2337 case ICmpInst::ICMP_SGE:
2338 return CI->getValue().isNegative() ?
2339 ConstantInt::getTrue(CI->getContext()) :
2340 ConstantInt::getFalse(CI->getContext());
2342 case ICmpInst::ICMP_SLT:
2343 case ICmpInst::ICMP_SLE:
2344 return CI->getValue().isNegative() ?
2345 ConstantInt::getFalse(CI->getContext()) :
2346 ConstantInt::getTrue(CI->getContext());
2352 if (isa<SExtInst>(LHS)) {
2353 // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
2355 if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
2356 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2357 // Compare X and Y. Note that the predicate does not change.
2358 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2362 // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
2363 // too. If not, then try to deduce the result of the comparison.
2364 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2365 // Compute the constant that would happen if we truncated to SrcTy then
2366 // reextended to DstTy.
2367 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2368 Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
2370 // If the re-extended constant didn't change then this is effectively
2371 // also a case of comparing two sign-extended values.
2372 if (RExt == CI && MaxRecurse)
2373 if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
2376 // Otherwise the upper bits of LHS are all equal, while RHS has varying
2377 // bits there. Use this to work out the result of the comparison.
2380 default: llvm_unreachable("Unknown ICmp predicate!");
2381 case ICmpInst::ICMP_EQ:
2382 return ConstantInt::getFalse(CI->getContext());
2383 case ICmpInst::ICMP_NE:
2384 return ConstantInt::getTrue(CI->getContext());
2386 // If RHS is non-negative then LHS <s RHS. If RHS is negative then
2388 case ICmpInst::ICMP_SGT:
2389 case ICmpInst::ICMP_SGE:
2390 return CI->getValue().isNegative() ?
2391 ConstantInt::getTrue(CI->getContext()) :
2392 ConstantInt::getFalse(CI->getContext());
2393 case ICmpInst::ICMP_SLT:
2394 case ICmpInst::ICMP_SLE:
2395 return CI->getValue().isNegative() ?
2396 ConstantInt::getFalse(CI->getContext()) :
2397 ConstantInt::getTrue(CI->getContext());
2399 // If LHS is non-negative then LHS <u RHS. If LHS is negative then
2401 case ICmpInst::ICMP_UGT:
2402 case ICmpInst::ICMP_UGE:
2403 // Comparison is true iff the LHS <s 0.
2405 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
2406 Constant::getNullValue(SrcTy),
2410 case ICmpInst::ICMP_ULT:
2411 case ICmpInst::ICMP_ULE:
2412 // Comparison is true iff the LHS >=s 0.
2414 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
2415 Constant::getNullValue(SrcTy),
2425 // If a bit is known to be zero for A and known to be one for B,
2426 // then A and B cannot be equal.
2427 if (ICmpInst::isEquality(Pred)) {
2428 if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2429 uint32_t BitWidth = CI->getBitWidth();
2430 APInt LHSKnownZero(BitWidth, 0);
2431 APInt LHSKnownOne(BitWidth, 0);
2432 computeKnownBits(LHS, LHSKnownZero, LHSKnownOne, Q.DL,
2433 0, Q.AT, Q.CxtI, Q.DT);
2434 APInt RHSKnownZero(BitWidth, 0);
2435 APInt RHSKnownOne(BitWidth, 0);
2436 computeKnownBits(RHS, RHSKnownZero, RHSKnownOne, Q.DL,
2437 0, Q.AT, Q.CxtI, Q.DT);
2438 if (((LHSKnownOne & RHSKnownZero) != 0) ||
2439 ((LHSKnownZero & RHSKnownOne) != 0))
2440 return (Pred == ICmpInst::ICMP_EQ)
2441 ? ConstantInt::getFalse(CI->getContext())
2442 : ConstantInt::getTrue(CI->getContext());
2446 // Special logic for binary operators.
2447 BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
2448 BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
2449 if (MaxRecurse && (LBO || RBO)) {
2450 // Analyze the case when either LHS or RHS is an add instruction.
2451 Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
2452 // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
2453 bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
2454 if (LBO && LBO->getOpcode() == Instruction::Add) {
2455 A = LBO->getOperand(0); B = LBO->getOperand(1);
2456 NoLHSWrapProblem = ICmpInst::isEquality(Pred) ||
2457 (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
2458 (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
2460 if (RBO && RBO->getOpcode() == Instruction::Add) {
2461 C = RBO->getOperand(0); D = RBO->getOperand(1);
2462 NoRHSWrapProblem = ICmpInst::isEquality(Pred) ||
2463 (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
2464 (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
2467 // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
2468 if ((A == RHS || B == RHS) && NoLHSWrapProblem)
2469 if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
2470 Constant::getNullValue(RHS->getType()),
2474 // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
2475 if ((C == LHS || D == LHS) && NoRHSWrapProblem)
2476 if (Value *V = SimplifyICmpInst(Pred,
2477 Constant::getNullValue(LHS->getType()),
2478 C == LHS ? D : C, Q, MaxRecurse-1))
2481 // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
2482 if (A && C && (A == C || A == D || B == C || B == D) &&
2483 NoLHSWrapProblem && NoRHSWrapProblem) {
2484 // Determine Y and Z in the form icmp (X+Y), (X+Z).
2487 // C + B == C + D -> B == D
2490 } else if (A == D) {
2491 // D + B == C + D -> B == C
2494 } else if (B == C) {
2495 // A + C == C + D -> A == D
2500 // A + D == C + D -> A == C
2504 if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse-1))
2509 // 0 - (zext X) pred C
2510 if (!CmpInst::isUnsigned(Pred) && match(LHS, m_Neg(m_ZExt(m_Value())))) {
2511 if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS)) {
2512 if (RHSC->getValue().isStrictlyPositive()) {
2513 if (Pred == ICmpInst::ICMP_SLT)
2514 return ConstantInt::getTrue(RHSC->getContext());
2515 if (Pred == ICmpInst::ICMP_SGE)
2516 return ConstantInt::getFalse(RHSC->getContext());
2517 if (Pred == ICmpInst::ICMP_EQ)
2518 return ConstantInt::getFalse(RHSC->getContext());
2519 if (Pred == ICmpInst::ICMP_NE)
2520 return ConstantInt::getTrue(RHSC->getContext());
2522 if (RHSC->getValue().isNonNegative()) {
2523 if (Pred == ICmpInst::ICMP_SLE)
2524 return ConstantInt::getTrue(RHSC->getContext());
2525 if (Pred == ICmpInst::ICMP_SGT)
2526 return ConstantInt::getFalse(RHSC->getContext());
2531 // icmp pred (urem X, Y), Y
2532 if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
2533 bool KnownNonNegative, KnownNegative;
2537 case ICmpInst::ICMP_SGT:
2538 case ICmpInst::ICMP_SGE:
2539 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.DL,
2540 0, Q.AT, Q.CxtI, Q.DT);
2541 if (!KnownNonNegative)
2544 case ICmpInst::ICMP_EQ:
2545 case ICmpInst::ICMP_UGT:
2546 case ICmpInst::ICMP_UGE:
2547 return getFalse(ITy);
2548 case ICmpInst::ICMP_SLT:
2549 case ICmpInst::ICMP_SLE:
2550 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.DL,
2551 0, Q.AT, Q.CxtI, Q.DT);
2552 if (!KnownNonNegative)
2555 case ICmpInst::ICMP_NE:
2556 case ICmpInst::ICMP_ULT:
2557 case ICmpInst::ICMP_ULE:
2558 return getTrue(ITy);
2562 // icmp pred X, (urem Y, X)
2563 if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
2564 bool KnownNonNegative, KnownNegative;
2568 case ICmpInst::ICMP_SGT:
2569 case ICmpInst::ICMP_SGE:
2570 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.DL,
2571 0, Q.AT, Q.CxtI, Q.DT);
2572 if (!KnownNonNegative)
2575 case ICmpInst::ICMP_NE:
2576 case ICmpInst::ICMP_UGT:
2577 case ICmpInst::ICMP_UGE:
2578 return getTrue(ITy);
2579 case ICmpInst::ICMP_SLT:
2580 case ICmpInst::ICMP_SLE:
2581 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.DL,
2582 0, Q.AT, Q.CxtI, Q.DT);
2583 if (!KnownNonNegative)
2586 case ICmpInst::ICMP_EQ:
2587 case ICmpInst::ICMP_ULT:
2588 case ICmpInst::ICMP_ULE:
2589 return getFalse(ITy);
2594 if (LBO && match(LBO, m_UDiv(m_Specific(RHS), m_Value()))) {
2595 // icmp pred (X /u Y), X
2596 if (Pred == ICmpInst::ICMP_UGT)
2597 return getFalse(ITy);
2598 if (Pred == ICmpInst::ICMP_ULE)
2599 return getTrue(ITy);
2606 // where CI2 is a power of 2 and CI isn't
2607 if (auto *CI = dyn_cast<ConstantInt>(RHS)) {
2608 const APInt *CI2Val, *CIVal = &CI->getValue();
2609 if (LBO && match(LBO, m_Shl(m_APInt(CI2Val), m_Value())) &&
2610 CI2Val->isPowerOf2()) {
2611 if (!CIVal->isPowerOf2()) {
2612 // CI2 << X can equal zero in some circumstances,
2613 // this simplification is unsafe if CI is zero.
2615 // We know it is safe if:
2616 // - The shift is nsw, we can't shift out the one bit.
2617 // - The shift is nuw, we can't shift out the one bit.
2620 if (LBO->hasNoSignedWrap() || LBO->hasNoUnsignedWrap() ||
2621 *CI2Val == 1 || !CI->isZero()) {
2622 if (Pred == ICmpInst::ICMP_EQ)
2623 return ConstantInt::getFalse(RHS->getContext());
2624 if (Pred == ICmpInst::ICMP_NE)
2625 return ConstantInt::getTrue(RHS->getContext());
2628 if (CIVal->isSignBit() && *CI2Val == 1) {
2629 if (Pred == ICmpInst::ICMP_UGT)
2630 return ConstantInt::getFalse(RHS->getContext());
2631 if (Pred == ICmpInst::ICMP_ULE)
2632 return ConstantInt::getTrue(RHS->getContext());
2637 if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
2638 LBO->getOperand(1) == RBO->getOperand(1)) {
2639 switch (LBO->getOpcode()) {
2641 case Instruction::UDiv:
2642 case Instruction::LShr:
2643 if (ICmpInst::isSigned(Pred))
2646 case Instruction::SDiv:
2647 case Instruction::AShr:
2648 if (!LBO->isExact() || !RBO->isExact())
2650 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2651 RBO->getOperand(0), Q, MaxRecurse-1))
2654 case Instruction::Shl: {
2655 bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
2656 bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
2659 if (!NSW && ICmpInst::isSigned(Pred))
2661 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2662 RBO->getOperand(0), Q, MaxRecurse-1))
2669 // Simplify comparisons involving max/min.
2671 CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE;
2672 CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
2674 // Signed variants on "max(a,b)>=a -> true".
2675 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2676 if (A != RHS) std::swap(A, B); // smax(A, B) pred A.
2677 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2678 // We analyze this as smax(A, B) pred A.
2680 } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
2681 (A == LHS || B == LHS)) {
2682 if (A != LHS) std::swap(A, B); // A pred smax(A, B).
2683 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2684 // We analyze this as smax(A, B) swapped-pred A.
2685 P = CmpInst::getSwappedPredicate(Pred);
2686 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2687 (A == RHS || B == RHS)) {
2688 if (A != RHS) std::swap(A, B); // smin(A, B) pred A.
2689 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2690 // We analyze this as smax(-A, -B) swapped-pred -A.
2691 // Note that we do not need to actually form -A or -B thanks to EqP.
2692 P = CmpInst::getSwappedPredicate(Pred);
2693 } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
2694 (A == LHS || B == LHS)) {
2695 if (A != LHS) std::swap(A, B); // A pred smin(A, B).
2696 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2697 // We analyze this as smax(-A, -B) pred -A.
2698 // Note that we do not need to actually form -A or -B thanks to EqP.
2701 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2702 // Cases correspond to "max(A, B) p A".
2706 case CmpInst::ICMP_EQ:
2707 case CmpInst::ICMP_SLE:
2708 // Equivalent to "A EqP B". This may be the same as the condition tested
2709 // in the max/min; if so, we can just return that.
2710 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2712 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2714 // Otherwise, see if "A EqP B" simplifies.
2716 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2719 case CmpInst::ICMP_NE:
2720 case CmpInst::ICMP_SGT: {
2721 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2722 // Equivalent to "A InvEqP B". This may be the same as the condition
2723 // tested in the max/min; if so, we can just return that.
2724 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2726 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2728 // Otherwise, see if "A InvEqP B" simplifies.
2730 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2734 case CmpInst::ICMP_SGE:
2736 return getTrue(ITy);
2737 case CmpInst::ICMP_SLT:
2739 return getFalse(ITy);
2743 // Unsigned variants on "max(a,b)>=a -> true".
2744 P = CmpInst::BAD_ICMP_PREDICATE;
2745 if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2746 if (A != RHS) std::swap(A, B); // umax(A, B) pred A.
2747 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2748 // We analyze this as umax(A, B) pred A.
2750 } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
2751 (A == LHS || B == LHS)) {
2752 if (A != LHS) std::swap(A, B); // A pred umax(A, B).
2753 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2754 // We analyze this as umax(A, B) swapped-pred A.
2755 P = CmpInst::getSwappedPredicate(Pred);
2756 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2757 (A == RHS || B == RHS)) {
2758 if (A != RHS) std::swap(A, B); // umin(A, B) pred A.
2759 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2760 // We analyze this as umax(-A, -B) swapped-pred -A.
2761 // Note that we do not need to actually form -A or -B thanks to EqP.
2762 P = CmpInst::getSwappedPredicate(Pred);
2763 } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
2764 (A == LHS || B == LHS)) {
2765 if (A != LHS) std::swap(A, B); // A pred umin(A, B).
2766 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2767 // We analyze this as umax(-A, -B) pred -A.
2768 // Note that we do not need to actually form -A or -B thanks to EqP.
2771 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2772 // Cases correspond to "max(A, B) p A".
2776 case CmpInst::ICMP_EQ:
2777 case CmpInst::ICMP_ULE:
2778 // Equivalent to "A EqP B". This may be the same as the condition tested
2779 // in the max/min; if so, we can just return that.
2780 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2782 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2784 // Otherwise, see if "A EqP B" simplifies.
2786 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2789 case CmpInst::ICMP_NE:
2790 case CmpInst::ICMP_UGT: {
2791 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2792 // Equivalent to "A InvEqP B". This may be the same as the condition
2793 // tested in the max/min; if so, we can just return that.
2794 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2796 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2798 // Otherwise, see if "A InvEqP B" simplifies.
2800 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2804 case CmpInst::ICMP_UGE:
2806 return getTrue(ITy);
2807 case CmpInst::ICMP_ULT:
2809 return getFalse(ITy);
2813 // Variants on "max(x,y) >= min(x,z)".
2815 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
2816 match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
2817 (A == C || A == D || B == C || B == D)) {
2818 // max(x, ?) pred min(x, ?).
2819 if (Pred == CmpInst::ICMP_SGE)
2821 return getTrue(ITy);
2822 if (Pred == CmpInst::ICMP_SLT)
2824 return getFalse(ITy);
2825 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2826 match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
2827 (A == C || A == D || B == C || B == D)) {
2828 // min(x, ?) pred max(x, ?).
2829 if (Pred == CmpInst::ICMP_SLE)
2831 return getTrue(ITy);
2832 if (Pred == CmpInst::ICMP_SGT)
2834 return getFalse(ITy);
2835 } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
2836 match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
2837 (A == C || A == D || B == C || B == D)) {
2838 // max(x, ?) pred min(x, ?).
2839 if (Pred == CmpInst::ICMP_UGE)
2841 return getTrue(ITy);
2842 if (Pred == CmpInst::ICMP_ULT)
2844 return getFalse(ITy);
2845 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2846 match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
2847 (A == C || A == D || B == C || B == D)) {
2848 // min(x, ?) pred max(x, ?).
2849 if (Pred == CmpInst::ICMP_ULE)
2851 return getTrue(ITy);
2852 if (Pred == CmpInst::ICMP_UGT)
2854 return getFalse(ITy);
2857 // Simplify comparisons of related pointers using a powerful, recursive
2858 // GEP-walk when we have target data available..
2859 if (LHS->getType()->isPointerTy())
2860 if (Constant *C = computePointerICmp(Q.DL, Q.TLI, Pred, LHS, RHS))
2863 if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
2864 if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
2865 if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
2866 GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
2867 (ICmpInst::isEquality(Pred) ||
2868 (GLHS->isInBounds() && GRHS->isInBounds() &&
2869 Pred == ICmpInst::getSignedPredicate(Pred)))) {
2870 // The bases are equal and the indices are constant. Build a constant
2871 // expression GEP with the same indices and a null base pointer to see
2872 // what constant folding can make out of it.
2873 Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
2874 SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
2875 Constant *NewLHS = ConstantExpr::getGetElementPtr(Null, IndicesLHS);
2877 SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
2878 Constant *NewRHS = ConstantExpr::getGetElementPtr(Null, IndicesRHS);
2879 return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
2884 // If the comparison is with the result of a select instruction, check whether
2885 // comparing with either branch of the select always yields the same value.
2886 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2887 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
2890 // If the comparison is with the result of a phi instruction, check whether
2891 // doing the compare with each incoming phi value yields a common result.
2892 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2893 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
2899 Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2900 const DataLayout *DL,
2901 const TargetLibraryInfo *TLI,
2902 const DominatorTree *DT,
2903 AssumptionTracker *AT,
2904 Instruction *CxtI) {
2905 return ::SimplifyICmpInst(Predicate, LHS, RHS, Query (DL, TLI, DT, AT, CxtI),
2909 /// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can
2910 /// fold the result. If not, this returns null.
2911 static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2912 const Query &Q, unsigned MaxRecurse) {
2913 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
2914 assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
2916 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
2917 if (Constant *CRHS = dyn_cast<Constant>(RHS))
2918 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
2920 // If we have a constant, make sure it is on the RHS.
2921 std::swap(LHS, RHS);
2922 Pred = CmpInst::getSwappedPredicate(Pred);
2925 // Fold trivial predicates.
2926 if (Pred == FCmpInst::FCMP_FALSE)
2927 return ConstantInt::get(GetCompareTy(LHS), 0);
2928 if (Pred == FCmpInst::FCMP_TRUE)
2929 return ConstantInt::get(GetCompareTy(LHS), 1);
2931 if (isa<UndefValue>(RHS)) // fcmp pred X, undef -> undef
2932 return UndefValue::get(GetCompareTy(LHS));
2934 // fcmp x,x -> true/false. Not all compares are foldable.
2936 if (CmpInst::isTrueWhenEqual(Pred))
2937 return ConstantInt::get(GetCompareTy(LHS), 1);
2938 if (CmpInst::isFalseWhenEqual(Pred))
2939 return ConstantInt::get(GetCompareTy(LHS), 0);
2942 // Handle fcmp with constant RHS
2943 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
2944 // If the constant is a nan, see if we can fold the comparison based on it.
2945 if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHSC)) {
2946 if (CFP->getValueAPF().isNaN()) {
2947 if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo"
2948 return ConstantInt::getFalse(CFP->getContext());
2949 assert(FCmpInst::isUnordered(Pred) &&
2950 "Comparison must be either ordered or unordered!");
2951 // True if unordered.
2952 return ConstantInt::getTrue(CFP->getContext());
2954 // Check whether the constant is an infinity.
2955 if (CFP->getValueAPF().isInfinity()) {
2956 if (CFP->getValueAPF().isNegative()) {
2958 case FCmpInst::FCMP_OLT:
2959 // No value is ordered and less than negative infinity.
2960 return ConstantInt::getFalse(CFP->getContext());
2961 case FCmpInst::FCMP_UGE:
2962 // All values are unordered with or at least negative infinity.
2963 return ConstantInt::getTrue(CFP->getContext());
2969 case FCmpInst::FCMP_OGT:
2970 // No value is ordered and greater than infinity.
2971 return ConstantInt::getFalse(CFP->getContext());
2972 case FCmpInst::FCMP_ULE:
2973 // All values are unordered with and at most infinity.
2974 return ConstantInt::getTrue(CFP->getContext());
2983 // If the comparison is with the result of a select instruction, check whether
2984 // comparing with either branch of the select always yields the same value.
2985 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2986 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
2989 // If the comparison is with the result of a phi instruction, check whether
2990 // doing the compare with each incoming phi value yields a common result.
2991 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2992 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
2998 Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2999 const DataLayout *DL,
3000 const TargetLibraryInfo *TLI,
3001 const DominatorTree *DT,
3002 AssumptionTracker *AT,
3003 const Instruction *CxtI) {
3004 return ::SimplifyFCmpInst(Predicate, LHS, RHS, Query (DL, TLI, DT, AT, CxtI),
3008 /// SimplifySelectInst - Given operands for a SelectInst, see if we can fold
3009 /// the result. If not, this returns null.
3010 static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal,
3011 Value *FalseVal, const Query &Q,
3012 unsigned MaxRecurse) {
3013 // select true, X, Y -> X
3014 // select false, X, Y -> Y
3015 if (Constant *CB = dyn_cast<Constant>(CondVal)) {
3016 if (CB->isAllOnesValue())
3018 if (CB->isNullValue())
3022 // select C, X, X -> X
3023 if (TrueVal == FalseVal)
3026 if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y
3027 if (isa<Constant>(TrueVal))
3031 if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X
3033 if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
3039 Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
3040 const DataLayout *DL,
3041 const TargetLibraryInfo *TLI,
3042 const DominatorTree *DT,
3043 AssumptionTracker *AT,
3044 const Instruction *CxtI) {
3045 return ::SimplifySelectInst(Cond, TrueVal, FalseVal,
3046 Query (DL, TLI, DT, AT, CxtI), RecursionLimit);
3049 /// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
3050 /// fold the result. If not, this returns null.
3051 static Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const Query &Q, unsigned) {
3052 // The type of the GEP pointer operand.
3053 PointerType *PtrTy = cast<PointerType>(Ops[0]->getType()->getScalarType());
3054 unsigned AS = PtrTy->getAddressSpace();
3056 // getelementptr P -> P.
3057 if (Ops.size() == 1)
3060 // Compute the (pointer) type returned by the GEP instruction.
3061 Type *LastType = GetElementPtrInst::getIndexedType(PtrTy, Ops.slice(1));
3062 Type *GEPTy = PointerType::get(LastType, AS);
3063 if (VectorType *VT = dyn_cast<VectorType>(Ops[0]->getType()))
3064 GEPTy = VectorType::get(GEPTy, VT->getNumElements());
3066 if (isa<UndefValue>(Ops[0]))
3067 return UndefValue::get(GEPTy);
3069 if (Ops.size() == 2) {
3070 // getelementptr P, 0 -> P.
3071 if (match(Ops[1], m_Zero()))
3074 Type *Ty = PtrTy->getElementType();
3075 if (Q.DL && Ty->isSized()) {
3078 uint64_t TyAllocSize = Q.DL->getTypeAllocSize(Ty);
3079 // getelementptr P, N -> P if P points to a type of zero size.
3080 if (TyAllocSize == 0)
3083 // The following transforms are only safe if the ptrtoint cast
3084 // doesn't truncate the pointers.
3085 if (Ops[1]->getType()->getScalarSizeInBits() ==
3086 Q.DL->getPointerSizeInBits(AS)) {
3087 auto PtrToIntOrZero = [GEPTy](Value *P) -> Value * {
3088 if (match(P, m_Zero()))
3089 return Constant::getNullValue(GEPTy);
3091 if (match(P, m_PtrToInt(m_Value(Temp))))
3092 if (Temp->getType() == GEPTy)
3097 // getelementptr V, (sub P, V) -> P if P points to a type of size 1.
3098 if (TyAllocSize == 1 &&
3099 match(Ops[1], m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0])))))
3100 if (Value *R = PtrToIntOrZero(P))
3103 // getelementptr V, (ashr (sub P, V), C) -> Q
3104 // if P points to a type of size 1 << C.
3106 m_AShr(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3107 m_ConstantInt(C))) &&
3108 TyAllocSize == 1ULL << C)
3109 if (Value *R = PtrToIntOrZero(P))
3112 // getelementptr V, (sdiv (sub P, V), C) -> Q
3113 // if P points to a type of size C.
3115 m_SDiv(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3116 m_SpecificInt(TyAllocSize))))
3117 if (Value *R = PtrToIntOrZero(P))
3123 // Check to see if this is constant foldable.
3124 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
3125 if (!isa<Constant>(Ops[i]))
3128 return ConstantExpr::getGetElementPtr(cast<Constant>(Ops[0]), Ops.slice(1));
3131 Value *llvm::SimplifyGEPInst(ArrayRef<Value *> Ops, const DataLayout *DL,
3132 const TargetLibraryInfo *TLI,
3133 const DominatorTree *DT, AssumptionTracker *AT,
3134 const Instruction *CxtI) {
3135 return ::SimplifyGEPInst(Ops, Query (DL, TLI, DT, AT, CxtI), RecursionLimit);
3138 /// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we
3139 /// can fold the result. If not, this returns null.
3140 static Value *SimplifyInsertValueInst(Value *Agg, Value *Val,
3141 ArrayRef<unsigned> Idxs, const Query &Q,
3143 if (Constant *CAgg = dyn_cast<Constant>(Agg))
3144 if (Constant *CVal = dyn_cast<Constant>(Val))
3145 return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
3147 // insertvalue x, undef, n -> x
3148 if (match(Val, m_Undef()))
3151 // insertvalue x, (extractvalue y, n), n
3152 if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
3153 if (EV->getAggregateOperand()->getType() == Agg->getType() &&
3154 EV->getIndices() == Idxs) {
3155 // insertvalue undef, (extractvalue y, n), n -> y
3156 if (match(Agg, m_Undef()))
3157 return EV->getAggregateOperand();
3159 // insertvalue y, (extractvalue y, n), n -> y
3160 if (Agg == EV->getAggregateOperand())
3167 Value *llvm::SimplifyInsertValueInst(Value *Agg, Value *Val,
3168 ArrayRef<unsigned> Idxs,
3169 const DataLayout *DL,
3170 const TargetLibraryInfo *TLI,
3171 const DominatorTree *DT,
3172 AssumptionTracker *AT,
3173 const Instruction *CxtI) {
3174 return ::SimplifyInsertValueInst(Agg, Val, Idxs,
3175 Query (DL, TLI, DT, AT, CxtI),
3179 /// SimplifyPHINode - See if we can fold the given phi. If not, returns null.
3180 static Value *SimplifyPHINode(PHINode *PN, const Query &Q) {
3181 // If all of the PHI's incoming values are the same then replace the PHI node
3182 // with the common value.
3183 Value *CommonValue = nullptr;
3184 bool HasUndefInput = false;
3185 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
3186 Value *Incoming = PN->getIncomingValue(i);
3187 // If the incoming value is the phi node itself, it can safely be skipped.
3188 if (Incoming == PN) continue;
3189 if (isa<UndefValue>(Incoming)) {
3190 // Remember that we saw an undef value, but otherwise ignore them.
3191 HasUndefInput = true;
3194 if (CommonValue && Incoming != CommonValue)
3195 return nullptr; // Not the same, bail out.
3196 CommonValue = Incoming;
3199 // If CommonValue is null then all of the incoming values were either undef or
3200 // equal to the phi node itself.
3202 return UndefValue::get(PN->getType());
3204 // If we have a PHI node like phi(X, undef, X), where X is defined by some
3205 // instruction, we cannot return X as the result of the PHI node unless it
3206 // dominates the PHI block.
3208 return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : nullptr;
3213 static Value *SimplifyTruncInst(Value *Op, Type *Ty, const Query &Q, unsigned) {
3214 if (Constant *C = dyn_cast<Constant>(Op))
3215 return ConstantFoldInstOperands(Instruction::Trunc, Ty, C, Q.DL, Q.TLI);
3220 Value *llvm::SimplifyTruncInst(Value *Op, Type *Ty, const DataLayout *DL,
3221 const TargetLibraryInfo *TLI,
3222 const DominatorTree *DT,
3223 AssumptionTracker *AT,
3224 const Instruction *CxtI) {
3225 return ::SimplifyTruncInst(Op, Ty, Query (DL, TLI, DT, AT, CxtI),
3229 //=== Helper functions for higher up the class hierarchy.
3231 /// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
3232 /// fold the result. If not, this returns null.
3233 static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
3234 const Query &Q, unsigned MaxRecurse) {
3236 case Instruction::Add:
3237 return SimplifyAddInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
3239 case Instruction::FAdd:
3240 return SimplifyFAddInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3242 case Instruction::Sub:
3243 return SimplifySubInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
3245 case Instruction::FSub:
3246 return SimplifyFSubInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3248 case Instruction::Mul: return SimplifyMulInst (LHS, RHS, Q, MaxRecurse);
3249 case Instruction::FMul:
3250 return SimplifyFMulInst (LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3251 case Instruction::SDiv: return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
3252 case Instruction::UDiv: return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
3253 case Instruction::FDiv: return SimplifyFDivInst(LHS, RHS, Q, MaxRecurse);
3254 case Instruction::SRem: return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
3255 case Instruction::URem: return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
3256 case Instruction::FRem: return SimplifyFRemInst(LHS, RHS, Q, MaxRecurse);
3257 case Instruction::Shl:
3258 return SimplifyShlInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
3260 case Instruction::LShr:
3261 return SimplifyLShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
3262 case Instruction::AShr:
3263 return SimplifyAShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
3264 case Instruction::And: return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
3265 case Instruction::Or: return SimplifyOrInst (LHS, RHS, Q, MaxRecurse);
3266 case Instruction::Xor: return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
3268 if (Constant *CLHS = dyn_cast<Constant>(LHS))
3269 if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
3270 Constant *COps[] = {CLHS, CRHS};
3271 return ConstantFoldInstOperands(Opcode, LHS->getType(), COps, Q.DL,
3275 // If the operation is associative, try some generic simplifications.
3276 if (Instruction::isAssociative(Opcode))
3277 if (Value *V = SimplifyAssociativeBinOp(Opcode, LHS, RHS, Q, MaxRecurse))
3280 // If the operation is with the result of a select instruction check whether
3281 // operating on either branch of the select always yields the same value.
3282 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3283 if (Value *V = ThreadBinOpOverSelect(Opcode, LHS, RHS, Q, MaxRecurse))
3286 // If the operation is with the result of a phi instruction, check whether
3287 // operating on all incoming values of the phi always yields the same value.
3288 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3289 if (Value *V = ThreadBinOpOverPHI(Opcode, LHS, RHS, Q, MaxRecurse))
3296 Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
3297 const DataLayout *DL, const TargetLibraryInfo *TLI,
3298 const DominatorTree *DT, AssumptionTracker *AT,
3299 const Instruction *CxtI) {
3300 return ::SimplifyBinOp(Opcode, LHS, RHS, Query (DL, TLI, DT, AT, CxtI),
3304 /// SimplifyCmpInst - Given operands for a CmpInst, see if we can
3305 /// fold the result.
3306 static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3307 const Query &Q, unsigned MaxRecurse) {
3308 if (CmpInst::isIntPredicate((CmpInst::Predicate)Predicate))
3309 return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
3310 return SimplifyFCmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
3313 Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3314 const DataLayout *DL, const TargetLibraryInfo *TLI,
3315 const DominatorTree *DT, AssumptionTracker *AT,
3316 const Instruction *CxtI) {
3317 return ::SimplifyCmpInst(Predicate, LHS, RHS, Query (DL, TLI, DT, AT, CxtI),
3321 static bool IsIdempotent(Intrinsic::ID ID) {
3323 default: return false;
3325 // Unary idempotent: f(f(x)) = f(x)
3326 case Intrinsic::fabs:
3327 case Intrinsic::floor:
3328 case Intrinsic::ceil:
3329 case Intrinsic::trunc:
3330 case Intrinsic::rint:
3331 case Intrinsic::nearbyint:
3332 case Intrinsic::round:
3337 template <typename IterTy>
3338 static Value *SimplifyIntrinsic(Intrinsic::ID IID, IterTy ArgBegin, IterTy ArgEnd,
3339 const Query &Q, unsigned MaxRecurse) {
3340 // Perform idempotent optimizations
3341 if (!IsIdempotent(IID))
3345 if (std::distance(ArgBegin, ArgEnd) == 1)
3346 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(*ArgBegin))
3347 if (II->getIntrinsicID() == IID)
3353 template <typename IterTy>
3354 static Value *SimplifyCall(Value *V, IterTy ArgBegin, IterTy ArgEnd,
3355 const Query &Q, unsigned MaxRecurse) {
3356 Type *Ty = V->getType();
3357 if (PointerType *PTy = dyn_cast<PointerType>(Ty))
3358 Ty = PTy->getElementType();
3359 FunctionType *FTy = cast<FunctionType>(Ty);
3361 // call undef -> undef
3362 if (isa<UndefValue>(V))
3363 return UndefValue::get(FTy->getReturnType());
3365 Function *F = dyn_cast<Function>(V);
3369 if (unsigned IID = F->getIntrinsicID())
3371 SimplifyIntrinsic((Intrinsic::ID) IID, ArgBegin, ArgEnd, Q, MaxRecurse))
3374 if (!canConstantFoldCallTo(F))
3377 SmallVector<Constant *, 4> ConstantArgs;
3378 ConstantArgs.reserve(ArgEnd - ArgBegin);
3379 for (IterTy I = ArgBegin, E = ArgEnd; I != E; ++I) {
3380 Constant *C = dyn_cast<Constant>(*I);
3383 ConstantArgs.push_back(C);
3386 return ConstantFoldCall(F, ConstantArgs, Q.TLI);
3389 Value *llvm::SimplifyCall(Value *V, User::op_iterator ArgBegin,
3390 User::op_iterator ArgEnd, const DataLayout *DL,
3391 const TargetLibraryInfo *TLI,
3392 const DominatorTree *DT, AssumptionTracker *AT,
3393 const Instruction *CxtI) {
3394 return ::SimplifyCall(V, ArgBegin, ArgEnd, Query(DL, TLI, DT, AT, CxtI),
3398 Value *llvm::SimplifyCall(Value *V, ArrayRef<Value *> Args,
3399 const DataLayout *DL, const TargetLibraryInfo *TLI,
3400 const DominatorTree *DT, AssumptionTracker *AT,
3401 const Instruction *CxtI) {
3402 return ::SimplifyCall(V, Args.begin(), Args.end(),
3403 Query(DL, TLI, DT, AT, CxtI), RecursionLimit);
3406 /// SimplifyInstruction - See if we can compute a simplified version of this
3407 /// instruction. If not, this returns null.
3408 Value *llvm::SimplifyInstruction(Instruction *I, const DataLayout *DL,
3409 const TargetLibraryInfo *TLI,
3410 const DominatorTree *DT,
3411 AssumptionTracker *AT) {
3414 switch (I->getOpcode()) {
3416 Result = ConstantFoldInstruction(I, DL, TLI);
3418 case Instruction::FAdd:
3419 Result = SimplifyFAddInst(I->getOperand(0), I->getOperand(1),
3420 I->getFastMathFlags(), DL, TLI, DT, AT, I);
3422 case Instruction::Add:
3423 Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
3424 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3425 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3426 DL, TLI, DT, AT, I);
3428 case Instruction::FSub:
3429 Result = SimplifyFSubInst(I->getOperand(0), I->getOperand(1),
3430 I->getFastMathFlags(), DL, TLI, DT, AT, I);
3432 case Instruction::Sub:
3433 Result = SimplifySubInst(I->getOperand(0), I->getOperand(1),
3434 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3435 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3436 DL, TLI, DT, AT, I);
3438 case Instruction::FMul:
3439 Result = SimplifyFMulInst(I->getOperand(0), I->getOperand(1),
3440 I->getFastMathFlags(), DL, TLI, DT, AT, I);
3442 case Instruction::Mul:
3443 Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1),
3444 DL, TLI, DT, AT, I);
3446 case Instruction::SDiv:
3447 Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1),
3448 DL, TLI, DT, AT, I);
3450 case Instruction::UDiv:
3451 Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1),
3452 DL, TLI, DT, AT, I);
3454 case Instruction::FDiv:
3455 Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1),
3456 DL, TLI, DT, AT, I);
3458 case Instruction::SRem:
3459 Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1),
3460 DL, TLI, DT, AT, I);
3462 case Instruction::URem:
3463 Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1),
3464 DL, TLI, DT, AT, I);
3466 case Instruction::FRem:
3467 Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1),
3468 DL, TLI, DT, AT, I);
3470 case Instruction::Shl:
3471 Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1),
3472 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3473 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3474 DL, TLI, DT, AT, I);
3476 case Instruction::LShr:
3477 Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
3478 cast<BinaryOperator>(I)->isExact(),
3479 DL, TLI, DT, AT, I);
3481 case Instruction::AShr:
3482 Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
3483 cast<BinaryOperator>(I)->isExact(),
3484 DL, TLI, DT, AT, I);
3486 case Instruction::And:
3487 Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1),
3488 DL, TLI, DT, AT, I);
3490 case Instruction::Or:
3491 Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT,
3494 case Instruction::Xor:
3495 Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1),
3496 DL, TLI, DT, AT, I);
3498 case Instruction::ICmp:
3499 Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
3500 I->getOperand(0), I->getOperand(1),
3501 DL, TLI, DT, AT, I);
3503 case Instruction::FCmp:
3504 Result = SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(),
3505 I->getOperand(0), I->getOperand(1),
3506 DL, TLI, DT, AT, I);
3508 case Instruction::Select:
3509 Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
3510 I->getOperand(2), DL, TLI, DT, AT, I);
3512 case Instruction::GetElementPtr: {
3513 SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end());
3514 Result = SimplifyGEPInst(Ops, DL, TLI, DT, AT, I);
3517 case Instruction::InsertValue: {
3518 InsertValueInst *IV = cast<InsertValueInst>(I);
3519 Result = SimplifyInsertValueInst(IV->getAggregateOperand(),
3520 IV->getInsertedValueOperand(),
3521 IV->getIndices(), DL, TLI, DT, AT, I);
3524 case Instruction::PHI:
3525 Result = SimplifyPHINode(cast<PHINode>(I), Query (DL, TLI, DT, AT, I));
3527 case Instruction::Call: {
3528 CallSite CS(cast<CallInst>(I));
3529 Result = SimplifyCall(CS.getCalledValue(), CS.arg_begin(), CS.arg_end(),
3530 DL, TLI, DT, AT, I);
3533 case Instruction::Trunc:
3534 Result = SimplifyTruncInst(I->getOperand(0), I->getType(), DL, TLI, DT,
3539 /// If called on unreachable code, the above logic may report that the
3540 /// instruction simplified to itself. Make life easier for users by
3541 /// detecting that case here, returning a safe value instead.
3542 return Result == I ? UndefValue::get(I->getType()) : Result;
3545 /// \brief Implementation of recursive simplification through an instructions
3548 /// This is the common implementation of the recursive simplification routines.
3549 /// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
3550 /// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
3551 /// instructions to process and attempt to simplify it using
3552 /// InstructionSimplify.
3554 /// This routine returns 'true' only when *it* simplifies something. The passed
3555 /// in simplified value does not count toward this.
3556 static bool replaceAndRecursivelySimplifyImpl(Instruction *I, Value *SimpleV,
3557 const DataLayout *DL,
3558 const TargetLibraryInfo *TLI,
3559 const DominatorTree *DT,
3560 AssumptionTracker *AT) {
3561 bool Simplified = false;
3562 SmallSetVector<Instruction *, 8> Worklist;
3564 // If we have an explicit value to collapse to, do that round of the
3565 // simplification loop by hand initially.
3567 for (User *U : I->users())
3569 Worklist.insert(cast<Instruction>(U));
3571 // Replace the instruction with its simplified value.
3572 I->replaceAllUsesWith(SimpleV);
3574 // Gracefully handle edge cases where the instruction is not wired into any
3577 I->eraseFromParent();
3582 // Note that we must test the size on each iteration, the worklist can grow.
3583 for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
3586 // See if this instruction simplifies.
3587 SimpleV = SimplifyInstruction(I, DL, TLI, DT, AT);
3593 // Stash away all the uses of the old instruction so we can check them for
3594 // recursive simplifications after a RAUW. This is cheaper than checking all
3595 // uses of To on the recursive step in most cases.
3596 for (User *U : I->users())
3597 Worklist.insert(cast<Instruction>(U));
3599 // Replace the instruction with its simplified value.
3600 I->replaceAllUsesWith(SimpleV);
3602 // Gracefully handle edge cases where the instruction is not wired into any
3605 I->eraseFromParent();
3610 bool llvm::recursivelySimplifyInstruction(Instruction *I,
3611 const DataLayout *DL,
3612 const TargetLibraryInfo *TLI,
3613 const DominatorTree *DT,
3614 AssumptionTracker *AT) {
3615 return replaceAndRecursivelySimplifyImpl(I, nullptr, DL, TLI, DT, AT);
3618 bool llvm::replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV,
3619 const DataLayout *DL,
3620 const TargetLibraryInfo *TLI,
3621 const DominatorTree *DT,
3622 AssumptionTracker *AT) {
3623 assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!");
3624 assert(SimpleV && "Must provide a simplified value.");
3625 return replaceAndRecursivelySimplifyImpl(I, SimpleV, DL, TLI, DT, AT);