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 // If the operation is with the result of a select instruction, check whether
1061 // operating on either branch of the select always yields the same value.
1062 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1063 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1066 // If the operation is with the result of a phi instruction, check whether
1067 // operating on all incoming values of the phi always yields the same value.
1068 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1069 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1075 /// SimplifySDivInst - Given operands for an SDiv, see if we can
1076 /// fold the result. If not, this returns null.
1077 static Value *SimplifySDivInst(Value *Op0, Value *Op1, const Query &Q,
1078 unsigned MaxRecurse) {
1079 if (Value *V = SimplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse))
1085 Value *llvm::SimplifySDivInst(Value *Op0, Value *Op1, const DataLayout *DL,
1086 const TargetLibraryInfo *TLI,
1087 const DominatorTree *DT,
1088 AssumptionTracker *AT,
1089 const Instruction *CxtI) {
1090 return ::SimplifySDivInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1094 /// SimplifyUDivInst - Given operands for a UDiv, see if we can
1095 /// fold the result. If not, this returns null.
1096 static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const Query &Q,
1097 unsigned MaxRecurse) {
1098 if (Value *V = SimplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse))
1104 Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const DataLayout *DL,
1105 const TargetLibraryInfo *TLI,
1106 const DominatorTree *DT,
1107 AssumptionTracker *AT,
1108 const Instruction *CxtI) {
1109 return ::SimplifyUDivInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1113 static Value *SimplifyFDivInst(Value *Op0, Value *Op1, const Query &Q,
1115 // undef / X -> undef (the undef could be a snan).
1116 if (match(Op0, m_Undef()))
1119 // X / undef -> undef
1120 if (match(Op1, m_Undef()))
1126 Value *llvm::SimplifyFDivInst(Value *Op0, Value *Op1, const DataLayout *DL,
1127 const TargetLibraryInfo *TLI,
1128 const DominatorTree *DT,
1129 AssumptionTracker *AT,
1130 const Instruction *CxtI) {
1131 return ::SimplifyFDivInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1135 /// SimplifyRem - Given operands for an SRem or URem, see if we can
1136 /// fold the result. If not, this returns null.
1137 static Value *SimplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
1138 const Query &Q, unsigned MaxRecurse) {
1139 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1140 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1141 Constant *Ops[] = { C0, C1 };
1142 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.DL, Q.TLI);
1146 // X % undef -> undef
1147 if (match(Op1, m_Undef()))
1151 if (match(Op0, m_Undef()))
1152 return Constant::getNullValue(Op0->getType());
1154 // 0 % X -> 0, we don't need to preserve faults!
1155 if (match(Op0, m_Zero()))
1158 // X % 0 -> undef, we don't need to preserve faults!
1159 if (match(Op1, m_Zero()))
1160 return UndefValue::get(Op0->getType());
1163 if (match(Op1, m_One()))
1164 return Constant::getNullValue(Op0->getType());
1166 if (Op0->getType()->isIntegerTy(1))
1167 // It can't be remainder by zero, hence it must be remainder by one.
1168 return Constant::getNullValue(Op0->getType());
1172 return Constant::getNullValue(Op0->getType());
1174 // (X % Y) % Y -> X % Y
1175 if ((Opcode == Instruction::SRem &&
1176 match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1177 (Opcode == Instruction::URem &&
1178 match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1181 // If the operation is with the result of a select instruction, check whether
1182 // operating on either branch of the select always yields the same value.
1183 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1184 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1187 // If the operation is with the result of a phi instruction, check whether
1188 // operating on all incoming values of the phi always yields the same value.
1189 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1190 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1196 /// SimplifySRemInst - Given operands for an SRem, see if we can
1197 /// fold the result. If not, this returns null.
1198 static Value *SimplifySRemInst(Value *Op0, Value *Op1, const Query &Q,
1199 unsigned MaxRecurse) {
1200 if (Value *V = SimplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse))
1206 Value *llvm::SimplifySRemInst(Value *Op0, Value *Op1, const DataLayout *DL,
1207 const TargetLibraryInfo *TLI,
1208 const DominatorTree *DT,
1209 AssumptionTracker *AT,
1210 const Instruction *CxtI) {
1211 return ::SimplifySRemInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1215 /// SimplifyURemInst - Given operands for a URem, see if we can
1216 /// fold the result. If not, this returns null.
1217 static Value *SimplifyURemInst(Value *Op0, Value *Op1, const Query &Q,
1218 unsigned MaxRecurse) {
1219 if (Value *V = SimplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse))
1225 Value *llvm::SimplifyURemInst(Value *Op0, Value *Op1, const DataLayout *DL,
1226 const TargetLibraryInfo *TLI,
1227 const DominatorTree *DT,
1228 AssumptionTracker *AT,
1229 const Instruction *CxtI) {
1230 return ::SimplifyURemInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1234 static Value *SimplifyFRemInst(Value *Op0, Value *Op1, const Query &,
1236 // undef % X -> undef (the undef could be a snan).
1237 if (match(Op0, m_Undef()))
1240 // X % undef -> undef
1241 if (match(Op1, m_Undef()))
1247 Value *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, const DataLayout *DL,
1248 const TargetLibraryInfo *TLI,
1249 const DominatorTree *DT,
1250 AssumptionTracker *AT,
1251 const Instruction *CxtI) {
1252 return ::SimplifyFRemInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1256 /// isUndefShift - Returns true if a shift by \c Amount always yields undef.
1257 static bool isUndefShift(Value *Amount) {
1258 Constant *C = dyn_cast<Constant>(Amount);
1262 // X shift by undef -> undef because it may shift by the bitwidth.
1263 if (isa<UndefValue>(C))
1266 // Shifting by the bitwidth or more is undefined.
1267 if (ConstantInt *CI = dyn_cast<ConstantInt>(C))
1268 if (CI->getValue().getLimitedValue() >=
1269 CI->getType()->getScalarSizeInBits())
1272 // If all lanes of a vector shift are undefined the whole shift is.
1273 if (isa<ConstantVector>(C) || isa<ConstantDataVector>(C)) {
1274 for (unsigned I = 0, E = C->getType()->getVectorNumElements(); I != E; ++I)
1275 if (!isUndefShift(C->getAggregateElement(I)))
1283 /// SimplifyShift - Given operands for an Shl, LShr or AShr, see if we can
1284 /// fold the result. If not, this returns null.
1285 static Value *SimplifyShift(unsigned Opcode, Value *Op0, Value *Op1,
1286 const Query &Q, unsigned MaxRecurse) {
1287 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1288 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1289 Constant *Ops[] = { C0, C1 };
1290 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.DL, Q.TLI);
1294 // 0 shift by X -> 0
1295 if (match(Op0, m_Zero()))
1298 // X shift by 0 -> X
1299 if (match(Op1, m_Zero()))
1302 // Fold undefined shifts.
1303 if (isUndefShift(Op1))
1304 return UndefValue::get(Op0->getType());
1306 // If the operation is with the result of a select instruction, check whether
1307 // operating on either branch of the select always yields the same value.
1308 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1309 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1312 // If the operation is with the result of a phi instruction, check whether
1313 // operating on all incoming values of the phi always yields the same value.
1314 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1315 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1321 /// SimplifyShlInst - Given operands for an Shl, see if we can
1322 /// fold the result. If not, this returns null.
1323 static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1324 const Query &Q, unsigned MaxRecurse) {
1325 if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse))
1329 if (match(Op0, m_Undef()))
1330 return Constant::getNullValue(Op0->getType());
1332 // (X >> A) << A -> X
1334 if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
1339 Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1340 const DataLayout *DL, const TargetLibraryInfo *TLI,
1341 const DominatorTree *DT, AssumptionTracker *AT,
1342 const Instruction *CxtI) {
1343 return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Query (DL, TLI, DT, AT, CxtI),
1347 /// SimplifyLShrInst - Given operands for an LShr, see if we can
1348 /// fold the result. If not, this returns null.
1349 static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1350 const Query &Q, unsigned MaxRecurse) {
1351 if (Value *V = SimplifyShift(Instruction::LShr, Op0, Op1, Q, MaxRecurse))
1356 return Constant::getNullValue(Op0->getType());
1359 if (match(Op0, m_Undef()))
1360 return Constant::getNullValue(Op0->getType());
1362 // (X << A) >> A -> X
1364 if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) &&
1365 cast<OverflowingBinaryOperator>(Op0)->hasNoUnsignedWrap())
1371 Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1372 const DataLayout *DL,
1373 const TargetLibraryInfo *TLI,
1374 const DominatorTree *DT,
1375 AssumptionTracker *AT,
1376 const Instruction *CxtI) {
1377 return ::SimplifyLShrInst(Op0, Op1, isExact, Query (DL, TLI, DT, AT, CxtI),
1381 /// SimplifyAShrInst - Given operands for an AShr, see if we can
1382 /// fold the result. If not, this returns null.
1383 static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1384 const Query &Q, unsigned MaxRecurse) {
1385 if (Value *V = SimplifyShift(Instruction::AShr, Op0, Op1, Q, MaxRecurse))
1390 return Constant::getNullValue(Op0->getType());
1392 // all ones >>a X -> all ones
1393 if (match(Op0, m_AllOnes()))
1396 // undef >>a X -> all ones
1397 if (match(Op0, m_Undef()))
1398 return Constant::getAllOnesValue(Op0->getType());
1400 // (X << A) >> A -> X
1402 if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) &&
1403 cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap())
1406 // Arithmetic shifting an all-sign-bit value is a no-op.
1407 unsigned NumSignBits = ComputeNumSignBits(Op0, Q.DL, 0, Q.AT, Q.CxtI, Q.DT);
1408 if (NumSignBits == Op0->getType()->getScalarSizeInBits())
1414 Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1415 const DataLayout *DL,
1416 const TargetLibraryInfo *TLI,
1417 const DominatorTree *DT,
1418 AssumptionTracker *AT,
1419 const Instruction *CxtI) {
1420 return ::SimplifyAShrInst(Op0, Op1, isExact, Query (DL, TLI, DT, AT, CxtI),
1424 // Simplify (and (icmp ...) (icmp ...)) to true when we can tell that the range
1425 // of possible values cannot be satisfied.
1426 static Value *SimplifyAndOfICmps(ICmpInst *Op0, ICmpInst *Op1) {
1427 ICmpInst::Predicate Pred0, Pred1;
1428 ConstantInt *CI1, *CI2;
1430 if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_ConstantInt(CI1)),
1431 m_ConstantInt(CI2))))
1434 if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Specific(CI1))))
1437 Type *ITy = Op0->getType();
1439 auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1440 bool isNSW = AddInst->hasNoSignedWrap();
1441 bool isNUW = AddInst->hasNoUnsignedWrap();
1443 const APInt &CI1V = CI1->getValue();
1444 const APInt &CI2V = CI2->getValue();
1445 const APInt Delta = CI2V - CI1V;
1446 if (CI1V.isStrictlyPositive()) {
1448 if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_SGT)
1449 return getFalse(ITy);
1450 if (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1451 return getFalse(ITy);
1454 if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_SGT)
1455 return getFalse(ITy);
1456 if (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1457 return getFalse(ITy);
1460 if (CI1V.getBoolValue() && isNUW) {
1462 if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT)
1463 return getFalse(ITy);
1465 if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGT)
1466 return getFalse(ITy);
1472 /// SimplifyAndInst - Given operands for an And, see if we can
1473 /// fold the result. If not, this returns null.
1474 static Value *SimplifyAndInst(Value *Op0, Value *Op1, const Query &Q,
1475 unsigned MaxRecurse) {
1476 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1477 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1478 Constant *Ops[] = { CLHS, CRHS };
1479 return ConstantFoldInstOperands(Instruction::And, CLHS->getType(),
1483 // Canonicalize the constant to the RHS.
1484 std::swap(Op0, Op1);
1488 if (match(Op1, m_Undef()))
1489 return Constant::getNullValue(Op0->getType());
1496 if (match(Op1, m_Zero()))
1500 if (match(Op1, m_AllOnes()))
1503 // A & ~A = ~A & A = 0
1504 if (match(Op0, m_Not(m_Specific(Op1))) ||
1505 match(Op1, m_Not(m_Specific(Op0))))
1506 return Constant::getNullValue(Op0->getType());
1509 Value *A = nullptr, *B = nullptr;
1510 if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
1511 (A == Op1 || B == Op1))
1515 if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
1516 (A == Op0 || B == Op0))
1519 // A & (-A) = A if A is a power of two or zero.
1520 if (match(Op0, m_Neg(m_Specific(Op1))) ||
1521 match(Op1, m_Neg(m_Specific(Op0)))) {
1522 if (isKnownToBeAPowerOfTwo(Op0, /*OrZero*/true, 0, Q.AT, Q.CxtI, Q.DT))
1524 if (isKnownToBeAPowerOfTwo(Op1, /*OrZero*/true, 0, Q.AT, Q.CxtI, Q.DT))
1528 if (auto *ICILHS = dyn_cast<ICmpInst>(Op0)) {
1529 if (auto *ICIRHS = dyn_cast<ICmpInst>(Op1)) {
1530 if (Value *V = SimplifyAndOfICmps(ICILHS, ICIRHS))
1532 if (Value *V = SimplifyAndOfICmps(ICIRHS, ICILHS))
1537 // Try some generic simplifications for associative operations.
1538 if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
1542 // And distributes over Or. Try some generic simplifications based on this.
1543 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1547 // And distributes over Xor. Try some generic simplifications based on this.
1548 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
1552 // If the operation is with the result of a select instruction, check whether
1553 // operating on either branch of the select always yields the same value.
1554 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1555 if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
1559 // If the operation is with the result of a phi instruction, check whether
1560 // operating on all incoming values of the phi always yields the same value.
1561 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1562 if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
1569 Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const DataLayout *DL,
1570 const TargetLibraryInfo *TLI,
1571 const DominatorTree *DT, AssumptionTracker *AT,
1572 const Instruction *CxtI) {
1573 return ::SimplifyAndInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1577 // Simplify (or (icmp ...) (icmp ...)) to true when we can tell that the union
1578 // contains all possible values.
1579 static Value *SimplifyOrOfICmps(ICmpInst *Op0, ICmpInst *Op1) {
1580 ICmpInst::Predicate Pred0, Pred1;
1581 ConstantInt *CI1, *CI2;
1583 if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_ConstantInt(CI1)),
1584 m_ConstantInt(CI2))))
1587 if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Specific(CI1))))
1590 Type *ITy = Op0->getType();
1592 auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1593 bool isNSW = AddInst->hasNoSignedWrap();
1594 bool isNUW = AddInst->hasNoUnsignedWrap();
1596 const APInt &CI1V = CI1->getValue();
1597 const APInt &CI2V = CI2->getValue();
1598 const APInt Delta = CI2V - CI1V;
1599 if (CI1V.isStrictlyPositive()) {
1601 if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_SLE)
1602 return getTrue(ITy);
1603 if (Pred0 == ICmpInst::ICMP_SGE && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1604 return getTrue(ITy);
1607 if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_SLE)
1608 return getTrue(ITy);
1609 if (Pred0 == ICmpInst::ICMP_SGT && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1610 return getTrue(ITy);
1613 if (CI1V.getBoolValue() && isNUW) {
1615 if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_ULE)
1616 return getTrue(ITy);
1618 if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_ULE)
1619 return getTrue(ITy);
1625 /// SimplifyOrInst - Given operands for an Or, see if we can
1626 /// fold the result. If not, this returns null.
1627 static Value *SimplifyOrInst(Value *Op0, Value *Op1, const Query &Q,
1628 unsigned MaxRecurse) {
1629 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1630 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1631 Constant *Ops[] = { CLHS, CRHS };
1632 return ConstantFoldInstOperands(Instruction::Or, CLHS->getType(),
1636 // Canonicalize the constant to the RHS.
1637 std::swap(Op0, Op1);
1641 if (match(Op1, m_Undef()))
1642 return Constant::getAllOnesValue(Op0->getType());
1649 if (match(Op1, m_Zero()))
1653 if (match(Op1, m_AllOnes()))
1656 // A | ~A = ~A | A = -1
1657 if (match(Op0, m_Not(m_Specific(Op1))) ||
1658 match(Op1, m_Not(m_Specific(Op0))))
1659 return Constant::getAllOnesValue(Op0->getType());
1662 Value *A = nullptr, *B = nullptr;
1663 if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
1664 (A == Op1 || B == Op1))
1668 if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
1669 (A == Op0 || B == Op0))
1672 // ~(A & ?) | A = -1
1673 if (match(Op0, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1674 (A == Op1 || B == Op1))
1675 return Constant::getAllOnesValue(Op1->getType());
1677 // A | ~(A & ?) = -1
1678 if (match(Op1, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1679 (A == Op0 || B == Op0))
1680 return Constant::getAllOnesValue(Op0->getType());
1682 if (auto *ICILHS = dyn_cast<ICmpInst>(Op0)) {
1683 if (auto *ICIRHS = dyn_cast<ICmpInst>(Op1)) {
1684 if (Value *V = SimplifyOrOfICmps(ICILHS, ICIRHS))
1686 if (Value *V = SimplifyOrOfICmps(ICIRHS, ICILHS))
1691 // Try some generic simplifications for associative operations.
1692 if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
1696 // Or distributes over And. Try some generic simplifications based on this.
1697 if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
1701 // If the operation is with the result of a select instruction, check whether
1702 // operating on either branch of the select always yields the same value.
1703 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1704 if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
1709 Value *C = nullptr, *D = nullptr;
1710 if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
1711 match(Op1, m_And(m_Value(B), m_Value(D)))) {
1712 ConstantInt *C1 = dyn_cast<ConstantInt>(C);
1713 ConstantInt *C2 = dyn_cast<ConstantInt>(D);
1714 if (C1 && C2 && (C1->getValue() == ~C2->getValue())) {
1715 // (A & C1)|(B & C2)
1716 // If we have: ((V + N) & C1) | (V & C2)
1717 // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
1718 // replace with V+N.
1720 if ((C2->getValue() & (C2->getValue() + 1)) == 0 && // C2 == 0+1+
1721 match(A, m_Add(m_Value(V1), m_Value(V2)))) {
1722 // Add commutes, try both ways.
1723 if (V1 == B && MaskedValueIsZero(V2, C2->getValue(), Q.DL,
1724 0, Q.AT, Q.CxtI, Q.DT))
1726 if (V2 == B && MaskedValueIsZero(V1, C2->getValue(), Q.DL,
1727 0, Q.AT, Q.CxtI, Q.DT))
1730 // Or commutes, try both ways.
1731 if ((C1->getValue() & (C1->getValue() + 1)) == 0 &&
1732 match(B, m_Add(m_Value(V1), m_Value(V2)))) {
1733 // Add commutes, try both ways.
1734 if (V1 == A && MaskedValueIsZero(V2, C1->getValue(), Q.DL,
1735 0, Q.AT, Q.CxtI, Q.DT))
1737 if (V2 == A && MaskedValueIsZero(V1, C1->getValue(), Q.DL,
1738 0, Q.AT, Q.CxtI, Q.DT))
1744 // If the operation is with the result of a phi instruction, check whether
1745 // operating on all incoming values of the phi always yields the same value.
1746 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1747 if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
1753 Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const DataLayout *DL,
1754 const TargetLibraryInfo *TLI,
1755 const DominatorTree *DT, AssumptionTracker *AT,
1756 const Instruction *CxtI) {
1757 return ::SimplifyOrInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1761 /// SimplifyXorInst - Given operands for a Xor, see if we can
1762 /// fold the result. If not, this returns null.
1763 static Value *SimplifyXorInst(Value *Op0, Value *Op1, const Query &Q,
1764 unsigned MaxRecurse) {
1765 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1766 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1767 Constant *Ops[] = { CLHS, CRHS };
1768 return ConstantFoldInstOperands(Instruction::Xor, CLHS->getType(),
1772 // Canonicalize the constant to the RHS.
1773 std::swap(Op0, Op1);
1776 // A ^ undef -> undef
1777 if (match(Op1, m_Undef()))
1781 if (match(Op1, m_Zero()))
1786 return Constant::getNullValue(Op0->getType());
1788 // A ^ ~A = ~A ^ A = -1
1789 if (match(Op0, m_Not(m_Specific(Op1))) ||
1790 match(Op1, m_Not(m_Specific(Op0))))
1791 return Constant::getAllOnesValue(Op0->getType());
1793 // Try some generic simplifications for associative operations.
1794 if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
1798 // Threading Xor over selects and phi nodes is pointless, so don't bother.
1799 // Threading over the select in "A ^ select(cond, B, C)" means evaluating
1800 // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
1801 // only if B and C are equal. If B and C are equal then (since we assume
1802 // that operands have already been simplified) "select(cond, B, C)" should
1803 // have been simplified to the common value of B and C already. Analysing
1804 // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
1805 // for threading over phi nodes.
1810 Value *llvm::SimplifyXorInst(Value *Op0, Value *Op1, const DataLayout *DL,
1811 const TargetLibraryInfo *TLI,
1812 const DominatorTree *DT, AssumptionTracker *AT,
1813 const Instruction *CxtI) {
1814 return ::SimplifyXorInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1818 static Type *GetCompareTy(Value *Op) {
1819 return CmpInst::makeCmpResultType(Op->getType());
1822 /// ExtractEquivalentCondition - Rummage around inside V looking for something
1823 /// equivalent to the comparison "LHS Pred RHS". Return such a value if found,
1824 /// otherwise return null. Helper function for analyzing max/min idioms.
1825 static Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred,
1826 Value *LHS, Value *RHS) {
1827 SelectInst *SI = dyn_cast<SelectInst>(V);
1830 CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
1833 Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
1834 if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
1836 if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
1837 LHS == CmpRHS && RHS == CmpLHS)
1842 // A significant optimization not implemented here is assuming that alloca
1843 // addresses are not equal to incoming argument values. They don't *alias*,
1844 // as we say, but that doesn't mean they aren't equal, so we take a
1845 // conservative approach.
1847 // This is inspired in part by C++11 5.10p1:
1848 // "Two pointers of the same type compare equal if and only if they are both
1849 // null, both point to the same function, or both represent the same
1852 // This is pretty permissive.
1854 // It's also partly due to C11 6.5.9p6:
1855 // "Two pointers compare equal if and only if both are null pointers, both are
1856 // pointers to the same object (including a pointer to an object and a
1857 // subobject at its beginning) or function, both are pointers to one past the
1858 // last element of the same array object, or one is a pointer to one past the
1859 // end of one array object and the other is a pointer to the start of a
1860 // different array object that happens to immediately follow the first array
1861 // object in the address space.)
1863 // C11's version is more restrictive, however there's no reason why an argument
1864 // couldn't be a one-past-the-end value for a stack object in the caller and be
1865 // equal to the beginning of a stack object in the callee.
1867 // If the C and C++ standards are ever made sufficiently restrictive in this
1868 // area, it may be possible to update LLVM's semantics accordingly and reinstate
1869 // this optimization.
1870 static Constant *computePointerICmp(const DataLayout *DL,
1871 const TargetLibraryInfo *TLI,
1872 CmpInst::Predicate Pred,
1873 Value *LHS, Value *RHS) {
1874 // First, skip past any trivial no-ops.
1875 LHS = LHS->stripPointerCasts();
1876 RHS = RHS->stripPointerCasts();
1878 // A non-null pointer is not equal to a null pointer.
1879 if (llvm::isKnownNonNull(LHS, TLI) && isa<ConstantPointerNull>(RHS) &&
1880 (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE))
1881 return ConstantInt::get(GetCompareTy(LHS),
1882 !CmpInst::isTrueWhenEqual(Pred));
1884 // We can only fold certain predicates on pointer comparisons.
1889 // Equality comaprisons are easy to fold.
1890 case CmpInst::ICMP_EQ:
1891 case CmpInst::ICMP_NE:
1894 // We can only handle unsigned relational comparisons because 'inbounds' on
1895 // a GEP only protects against unsigned wrapping.
1896 case CmpInst::ICMP_UGT:
1897 case CmpInst::ICMP_UGE:
1898 case CmpInst::ICMP_ULT:
1899 case CmpInst::ICMP_ULE:
1900 // However, we have to switch them to their signed variants to handle
1901 // negative indices from the base pointer.
1902 Pred = ICmpInst::getSignedPredicate(Pred);
1906 // Strip off any constant offsets so that we can reason about them.
1907 // It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets
1908 // here and compare base addresses like AliasAnalysis does, however there are
1909 // numerous hazards. AliasAnalysis and its utilities rely on special rules
1910 // governing loads and stores which don't apply to icmps. Also, AliasAnalysis
1911 // doesn't need to guarantee pointer inequality when it says NoAlias.
1912 Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
1913 Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
1915 // If LHS and RHS are related via constant offsets to the same base
1916 // value, we can replace it with an icmp which just compares the offsets.
1918 return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset);
1920 // Various optimizations for (in)equality comparisons.
1921 if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE) {
1922 // Different non-empty allocations that exist at the same time have
1923 // different addresses (if the program can tell). Global variables always
1924 // exist, so they always exist during the lifetime of each other and all
1925 // allocas. Two different allocas usually have different addresses...
1927 // However, if there's an @llvm.stackrestore dynamically in between two
1928 // allocas, they may have the same address. It's tempting to reduce the
1929 // scope of the problem by only looking at *static* allocas here. That would
1930 // cover the majority of allocas while significantly reducing the likelihood
1931 // of having an @llvm.stackrestore pop up in the middle. However, it's not
1932 // actually impossible for an @llvm.stackrestore to pop up in the middle of
1933 // an entry block. Also, if we have a block that's not attached to a
1934 // function, we can't tell if it's "static" under the current definition.
1935 // Theoretically, this problem could be fixed by creating a new kind of
1936 // instruction kind specifically for static allocas. Such a new instruction
1937 // could be required to be at the top of the entry block, thus preventing it
1938 // from being subject to a @llvm.stackrestore. Instcombine could even
1939 // convert regular allocas into these special allocas. It'd be nifty.
1940 // However, until then, this problem remains open.
1942 // So, we'll assume that two non-empty allocas have different addresses
1945 // With all that, if the offsets are within the bounds of their allocations
1946 // (and not one-past-the-end! so we can't use inbounds!), and their
1947 // allocations aren't the same, the pointers are not equal.
1949 // Note that it's not necessary to check for LHS being a global variable
1950 // address, due to canonicalization and constant folding.
1951 if (isa<AllocaInst>(LHS) &&
1952 (isa<AllocaInst>(RHS) || isa<GlobalVariable>(RHS))) {
1953 ConstantInt *LHSOffsetCI = dyn_cast<ConstantInt>(LHSOffset);
1954 ConstantInt *RHSOffsetCI = dyn_cast<ConstantInt>(RHSOffset);
1955 uint64_t LHSSize, RHSSize;
1956 if (LHSOffsetCI && RHSOffsetCI &&
1957 getObjectSize(LHS, LHSSize, DL, TLI) &&
1958 getObjectSize(RHS, RHSSize, DL, TLI)) {
1959 const APInt &LHSOffsetValue = LHSOffsetCI->getValue();
1960 const APInt &RHSOffsetValue = RHSOffsetCI->getValue();
1961 if (!LHSOffsetValue.isNegative() &&
1962 !RHSOffsetValue.isNegative() &&
1963 LHSOffsetValue.ult(LHSSize) &&
1964 RHSOffsetValue.ult(RHSSize)) {
1965 return ConstantInt::get(GetCompareTy(LHS),
1966 !CmpInst::isTrueWhenEqual(Pred));
1970 // Repeat the above check but this time without depending on DataLayout
1971 // or being able to compute a precise size.
1972 if (!cast<PointerType>(LHS->getType())->isEmptyTy() &&
1973 !cast<PointerType>(RHS->getType())->isEmptyTy() &&
1974 LHSOffset->isNullValue() &&
1975 RHSOffset->isNullValue())
1976 return ConstantInt::get(GetCompareTy(LHS),
1977 !CmpInst::isTrueWhenEqual(Pred));
1980 // Even if an non-inbounds GEP occurs along the path we can still optimize
1981 // equality comparisons concerning the result. We avoid walking the whole
1982 // chain again by starting where the last calls to
1983 // stripAndComputeConstantOffsets left off and accumulate the offsets.
1984 Constant *LHSNoBound = stripAndComputeConstantOffsets(DL, LHS, true);
1985 Constant *RHSNoBound = stripAndComputeConstantOffsets(DL, RHS, true);
1987 return ConstantExpr::getICmp(Pred,
1988 ConstantExpr::getAdd(LHSOffset, LHSNoBound),
1989 ConstantExpr::getAdd(RHSOffset, RHSNoBound));
1996 /// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
1997 /// fold the result. If not, this returns null.
1998 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
1999 const Query &Q, unsigned MaxRecurse) {
2000 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
2001 assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
2003 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
2004 if (Constant *CRHS = dyn_cast<Constant>(RHS))
2005 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
2007 // If we have a constant, make sure it is on the RHS.
2008 std::swap(LHS, RHS);
2009 Pred = CmpInst::getSwappedPredicate(Pred);
2012 Type *ITy = GetCompareTy(LHS); // The return type.
2013 Type *OpTy = LHS->getType(); // The operand type.
2015 // icmp X, X -> true/false
2016 // X icmp undef -> true/false. For example, icmp ugt %X, undef -> false
2017 // because X could be 0.
2018 if (LHS == RHS || isa<UndefValue>(RHS))
2019 return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
2021 // Special case logic when the operands have i1 type.
2022 if (OpTy->getScalarType()->isIntegerTy(1)) {
2025 case ICmpInst::ICMP_EQ:
2027 if (match(RHS, m_One()))
2030 case ICmpInst::ICMP_NE:
2032 if (match(RHS, m_Zero()))
2035 case ICmpInst::ICMP_UGT:
2037 if (match(RHS, m_Zero()))
2040 case ICmpInst::ICMP_UGE:
2042 if (match(RHS, m_One()))
2045 case ICmpInst::ICMP_SLT:
2047 if (match(RHS, m_Zero()))
2050 case ICmpInst::ICMP_SLE:
2052 if (match(RHS, m_One()))
2058 // If we are comparing with zero then try hard since this is a common case.
2059 if (match(RHS, m_Zero())) {
2060 bool LHSKnownNonNegative, LHSKnownNegative;
2062 default: llvm_unreachable("Unknown ICmp predicate!");
2063 case ICmpInst::ICMP_ULT:
2064 return getFalse(ITy);
2065 case ICmpInst::ICMP_UGE:
2066 return getTrue(ITy);
2067 case ICmpInst::ICMP_EQ:
2068 case ICmpInst::ICMP_ULE:
2069 if (isKnownNonZero(LHS, Q.DL, 0, Q.AT, Q.CxtI, Q.DT))
2070 return getFalse(ITy);
2072 case ICmpInst::ICMP_NE:
2073 case ICmpInst::ICMP_UGT:
2074 if (isKnownNonZero(LHS, Q.DL, 0, Q.AT, Q.CxtI, Q.DT))
2075 return getTrue(ITy);
2077 case ICmpInst::ICMP_SLT:
2078 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL,
2079 0, Q.AT, Q.CxtI, Q.DT);
2080 if (LHSKnownNegative)
2081 return getTrue(ITy);
2082 if (LHSKnownNonNegative)
2083 return getFalse(ITy);
2085 case ICmpInst::ICMP_SLE:
2086 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL,
2087 0, Q.AT, Q.CxtI, Q.DT);
2088 if (LHSKnownNegative)
2089 return getTrue(ITy);
2090 if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.DL,
2091 0, Q.AT, Q.CxtI, Q.DT))
2092 return getFalse(ITy);
2094 case ICmpInst::ICMP_SGE:
2095 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL,
2096 0, Q.AT, Q.CxtI, Q.DT);
2097 if (LHSKnownNegative)
2098 return getFalse(ITy);
2099 if (LHSKnownNonNegative)
2100 return getTrue(ITy);
2102 case ICmpInst::ICMP_SGT:
2103 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL,
2104 0, Q.AT, Q.CxtI, Q.DT);
2105 if (LHSKnownNegative)
2106 return getFalse(ITy);
2107 if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.DL,
2108 0, Q.AT, Q.CxtI, Q.DT))
2109 return getTrue(ITy);
2114 // See if we are doing a comparison with a constant integer.
2115 if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2116 // Rule out tautological comparisons (eg., ult 0 or uge 0).
2117 ConstantRange RHS_CR = ICmpInst::makeConstantRange(Pred, CI->getValue());
2118 if (RHS_CR.isEmptySet())
2119 return ConstantInt::getFalse(CI->getContext());
2120 if (RHS_CR.isFullSet())
2121 return ConstantInt::getTrue(CI->getContext());
2123 // Many binary operators with constant RHS have easy to compute constant
2124 // range. Use them to check whether the comparison is a tautology.
2125 unsigned Width = CI->getBitWidth();
2126 APInt Lower = APInt(Width, 0);
2127 APInt Upper = APInt(Width, 0);
2129 if (match(LHS, m_URem(m_Value(), m_ConstantInt(CI2)))) {
2130 // 'urem x, CI2' produces [0, CI2).
2131 Upper = CI2->getValue();
2132 } else if (match(LHS, m_SRem(m_Value(), m_ConstantInt(CI2)))) {
2133 // 'srem x, CI2' produces (-|CI2|, |CI2|).
2134 Upper = CI2->getValue().abs();
2135 Lower = (-Upper) + 1;
2136 } else if (match(LHS, m_UDiv(m_ConstantInt(CI2), m_Value()))) {
2137 // 'udiv CI2, x' produces [0, CI2].
2138 Upper = CI2->getValue() + 1;
2139 } else if (match(LHS, m_UDiv(m_Value(), m_ConstantInt(CI2)))) {
2140 // 'udiv x, CI2' produces [0, UINT_MAX / CI2].
2141 APInt NegOne = APInt::getAllOnesValue(Width);
2143 Upper = NegOne.udiv(CI2->getValue()) + 1;
2144 } else if (match(LHS, m_SDiv(m_ConstantInt(CI2), m_Value()))) {
2145 if (CI2->isMinSignedValue()) {
2146 // 'sdiv INT_MIN, x' produces [INT_MIN, INT_MIN / -2].
2147 Lower = CI2->getValue();
2148 Upper = Lower.lshr(1) + 1;
2150 // 'sdiv CI2, x' produces [-|CI2|, |CI2|].
2151 Upper = CI2->getValue().abs() + 1;
2152 Lower = (-Upper) + 1;
2154 } else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) {
2155 APInt IntMin = APInt::getSignedMinValue(Width);
2156 APInt IntMax = APInt::getSignedMaxValue(Width);
2157 APInt Val = CI2->getValue();
2158 if (Val.isAllOnesValue()) {
2159 // 'sdiv x, -1' produces [INT_MIN + 1, INT_MAX]
2160 // where CI2 != -1 and CI2 != 0 and CI2 != 1
2163 } else if (Val.countLeadingZeros() < Width - 1) {
2164 // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2]
2165 // where CI2 != -1 and CI2 != 0 and CI2 != 1
2166 Lower = IntMin.sdiv(Val);
2167 Upper = IntMax.sdiv(Val);
2168 if (Lower.sgt(Upper))
2169 std::swap(Lower, Upper);
2171 assert(Upper != Lower && "Upper part of range has wrapped!");
2173 } else if (match(LHS, m_NUWShl(m_ConstantInt(CI2), m_Value()))) {
2174 // 'shl nuw CI2, x' produces [CI2, CI2 << CLZ(CI2)]
2175 Lower = CI2->getValue();
2176 Upper = Lower.shl(Lower.countLeadingZeros()) + 1;
2177 } else if (match(LHS, m_NSWShl(m_ConstantInt(CI2), m_Value()))) {
2178 if (CI2->isNegative()) {
2179 // 'shl nsw CI2, x' produces [CI2 << CLO(CI2)-1, CI2]
2180 unsigned ShiftAmount = CI2->getValue().countLeadingOnes() - 1;
2181 Lower = CI2->getValue().shl(ShiftAmount);
2182 Upper = CI2->getValue() + 1;
2184 // 'shl nsw CI2, x' produces [CI2, CI2 << CLZ(CI2)-1]
2185 unsigned ShiftAmount = CI2->getValue().countLeadingZeros() - 1;
2186 Lower = CI2->getValue();
2187 Upper = CI2->getValue().shl(ShiftAmount) + 1;
2189 } else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) {
2190 // 'lshr x, CI2' produces [0, UINT_MAX >> CI2].
2191 APInt NegOne = APInt::getAllOnesValue(Width);
2192 if (CI2->getValue().ult(Width))
2193 Upper = NegOne.lshr(CI2->getValue()) + 1;
2194 } else if (match(LHS, m_LShr(m_ConstantInt(CI2), m_Value()))) {
2195 // 'lshr CI2, x' produces [CI2 >> (Width-1), CI2].
2196 unsigned ShiftAmount = Width - 1;
2197 if (!CI2->isZero() && cast<BinaryOperator>(LHS)->isExact())
2198 ShiftAmount = CI2->getValue().countTrailingZeros();
2199 Lower = CI2->getValue().lshr(ShiftAmount);
2200 Upper = CI2->getValue() + 1;
2201 } else if (match(LHS, m_AShr(m_Value(), m_ConstantInt(CI2)))) {
2202 // 'ashr x, CI2' produces [INT_MIN >> CI2, INT_MAX >> CI2].
2203 APInt IntMin = APInt::getSignedMinValue(Width);
2204 APInt IntMax = APInt::getSignedMaxValue(Width);
2205 if (CI2->getValue().ult(Width)) {
2206 Lower = IntMin.ashr(CI2->getValue());
2207 Upper = IntMax.ashr(CI2->getValue()) + 1;
2209 } else if (match(LHS, m_AShr(m_ConstantInt(CI2), m_Value()))) {
2210 unsigned ShiftAmount = Width - 1;
2211 if (!CI2->isZero() && cast<BinaryOperator>(LHS)->isExact())
2212 ShiftAmount = CI2->getValue().countTrailingZeros();
2213 if (CI2->isNegative()) {
2214 // 'ashr CI2, x' produces [CI2, CI2 >> (Width-1)]
2215 Lower = CI2->getValue();
2216 Upper = CI2->getValue().ashr(ShiftAmount) + 1;
2218 // 'ashr CI2, x' produces [CI2 >> (Width-1), CI2]
2219 Lower = CI2->getValue().ashr(ShiftAmount);
2220 Upper = CI2->getValue() + 1;
2222 } else if (match(LHS, m_Or(m_Value(), m_ConstantInt(CI2)))) {
2223 // 'or x, CI2' produces [CI2, UINT_MAX].
2224 Lower = CI2->getValue();
2225 } else if (match(LHS, m_And(m_Value(), m_ConstantInt(CI2)))) {
2226 // 'and x, CI2' produces [0, CI2].
2227 Upper = CI2->getValue() + 1;
2229 if (Lower != Upper) {
2230 ConstantRange LHS_CR = ConstantRange(Lower, Upper);
2231 if (RHS_CR.contains(LHS_CR))
2232 return ConstantInt::getTrue(RHS->getContext());
2233 if (RHS_CR.inverse().contains(LHS_CR))
2234 return ConstantInt::getFalse(RHS->getContext());
2238 // Compare of cast, for example (zext X) != 0 -> X != 0
2239 if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
2240 Instruction *LI = cast<CastInst>(LHS);
2241 Value *SrcOp = LI->getOperand(0);
2242 Type *SrcTy = SrcOp->getType();
2243 Type *DstTy = LI->getType();
2245 // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
2246 // if the integer type is the same size as the pointer type.
2247 if (MaxRecurse && Q.DL && isa<PtrToIntInst>(LI) &&
2248 Q.DL->getTypeSizeInBits(SrcTy) == DstTy->getPrimitiveSizeInBits()) {
2249 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
2250 // Transfer the cast to the constant.
2251 if (Value *V = SimplifyICmpInst(Pred, SrcOp,
2252 ConstantExpr::getIntToPtr(RHSC, SrcTy),
2255 } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
2256 if (RI->getOperand(0)->getType() == SrcTy)
2257 // Compare without the cast.
2258 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2264 if (isa<ZExtInst>(LHS)) {
2265 // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
2267 if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
2268 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2269 // Compare X and Y. Note that signed predicates become unsigned.
2270 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
2271 SrcOp, RI->getOperand(0), Q,
2275 // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
2276 // too. If not, then try to deduce the result of the comparison.
2277 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2278 // Compute the constant that would happen if we truncated to SrcTy then
2279 // reextended to DstTy.
2280 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2281 Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
2283 // If the re-extended constant didn't change then this is effectively
2284 // also a case of comparing two zero-extended values.
2285 if (RExt == CI && MaxRecurse)
2286 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
2287 SrcOp, Trunc, Q, MaxRecurse-1))
2290 // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
2291 // there. Use this to work out the result of the comparison.
2294 default: llvm_unreachable("Unknown ICmp predicate!");
2296 case ICmpInst::ICMP_EQ:
2297 case ICmpInst::ICMP_UGT:
2298 case ICmpInst::ICMP_UGE:
2299 return ConstantInt::getFalse(CI->getContext());
2301 case ICmpInst::ICMP_NE:
2302 case ICmpInst::ICMP_ULT:
2303 case ICmpInst::ICMP_ULE:
2304 return ConstantInt::getTrue(CI->getContext());
2306 // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
2307 // is non-negative then LHS <s RHS.
2308 case ICmpInst::ICMP_SGT:
2309 case ICmpInst::ICMP_SGE:
2310 return CI->getValue().isNegative() ?
2311 ConstantInt::getTrue(CI->getContext()) :
2312 ConstantInt::getFalse(CI->getContext());
2314 case ICmpInst::ICMP_SLT:
2315 case ICmpInst::ICMP_SLE:
2316 return CI->getValue().isNegative() ?
2317 ConstantInt::getFalse(CI->getContext()) :
2318 ConstantInt::getTrue(CI->getContext());
2324 if (isa<SExtInst>(LHS)) {
2325 // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
2327 if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
2328 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2329 // Compare X and Y. Note that the predicate does not change.
2330 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2334 // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
2335 // too. If not, then try to deduce the result of the comparison.
2336 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2337 // Compute the constant that would happen if we truncated to SrcTy then
2338 // reextended to DstTy.
2339 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2340 Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
2342 // If the re-extended constant didn't change then this is effectively
2343 // also a case of comparing two sign-extended values.
2344 if (RExt == CI && MaxRecurse)
2345 if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
2348 // Otherwise the upper bits of LHS are all equal, while RHS has varying
2349 // bits there. Use this to work out the result of the comparison.
2352 default: llvm_unreachable("Unknown ICmp predicate!");
2353 case ICmpInst::ICMP_EQ:
2354 return ConstantInt::getFalse(CI->getContext());
2355 case ICmpInst::ICMP_NE:
2356 return ConstantInt::getTrue(CI->getContext());
2358 // If RHS is non-negative then LHS <s RHS. If RHS is negative then
2360 case ICmpInst::ICMP_SGT:
2361 case ICmpInst::ICMP_SGE:
2362 return CI->getValue().isNegative() ?
2363 ConstantInt::getTrue(CI->getContext()) :
2364 ConstantInt::getFalse(CI->getContext());
2365 case ICmpInst::ICMP_SLT:
2366 case ICmpInst::ICMP_SLE:
2367 return CI->getValue().isNegative() ?
2368 ConstantInt::getFalse(CI->getContext()) :
2369 ConstantInt::getTrue(CI->getContext());
2371 // If LHS is non-negative then LHS <u RHS. If LHS is negative then
2373 case ICmpInst::ICMP_UGT:
2374 case ICmpInst::ICMP_UGE:
2375 // Comparison is true iff the LHS <s 0.
2377 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
2378 Constant::getNullValue(SrcTy),
2382 case ICmpInst::ICMP_ULT:
2383 case ICmpInst::ICMP_ULE:
2384 // Comparison is true iff the LHS >=s 0.
2386 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
2387 Constant::getNullValue(SrcTy),
2397 // If a bit is known to be zero for A and known to be one for B,
2398 // then A and B cannot be equal.
2399 if (ICmpInst::isEquality(Pred)) {
2400 if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2401 uint32_t BitWidth = CI->getBitWidth();
2402 APInt LHSKnownZero(BitWidth, 0);
2403 APInt LHSKnownOne(BitWidth, 0);
2404 computeKnownBits(LHS, LHSKnownZero, LHSKnownOne, Q.DL,
2405 0, Q.AT, Q.CxtI, Q.DT);
2406 APInt RHSKnownZero(BitWidth, 0);
2407 APInt RHSKnownOne(BitWidth, 0);
2408 computeKnownBits(RHS, RHSKnownZero, RHSKnownOne, Q.DL,
2409 0, Q.AT, Q.CxtI, Q.DT);
2410 if (((LHSKnownOne & RHSKnownZero) != 0) ||
2411 ((LHSKnownZero & RHSKnownOne) != 0))
2412 return (Pred == ICmpInst::ICMP_EQ)
2413 ? ConstantInt::getFalse(CI->getContext())
2414 : ConstantInt::getTrue(CI->getContext());
2418 // Special logic for binary operators.
2419 BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
2420 BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
2421 if (MaxRecurse && (LBO || RBO)) {
2422 // Analyze the case when either LHS or RHS is an add instruction.
2423 Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
2424 // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
2425 bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
2426 if (LBO && LBO->getOpcode() == Instruction::Add) {
2427 A = LBO->getOperand(0); B = LBO->getOperand(1);
2428 NoLHSWrapProblem = ICmpInst::isEquality(Pred) ||
2429 (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
2430 (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
2432 if (RBO && RBO->getOpcode() == Instruction::Add) {
2433 C = RBO->getOperand(0); D = RBO->getOperand(1);
2434 NoRHSWrapProblem = ICmpInst::isEquality(Pred) ||
2435 (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
2436 (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
2439 // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
2440 if ((A == RHS || B == RHS) && NoLHSWrapProblem)
2441 if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
2442 Constant::getNullValue(RHS->getType()),
2446 // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
2447 if ((C == LHS || D == LHS) && NoRHSWrapProblem)
2448 if (Value *V = SimplifyICmpInst(Pred,
2449 Constant::getNullValue(LHS->getType()),
2450 C == LHS ? D : C, Q, MaxRecurse-1))
2453 // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
2454 if (A && C && (A == C || A == D || B == C || B == D) &&
2455 NoLHSWrapProblem && NoRHSWrapProblem) {
2456 // Determine Y and Z in the form icmp (X+Y), (X+Z).
2459 // C + B == C + D -> B == D
2462 } else if (A == D) {
2463 // D + B == C + D -> B == C
2466 } else if (B == C) {
2467 // A + C == C + D -> A == D
2472 // A + D == C + D -> A == C
2476 if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse-1))
2481 // 0 - (zext X) pred C
2482 if (!CmpInst::isUnsigned(Pred) && match(LHS, m_Neg(m_ZExt(m_Value())))) {
2483 if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS)) {
2484 if (RHSC->getValue().isStrictlyPositive()) {
2485 if (Pred == ICmpInst::ICMP_SLT)
2486 return ConstantInt::getTrue(RHSC->getContext());
2487 if (Pred == ICmpInst::ICMP_SGE)
2488 return ConstantInt::getFalse(RHSC->getContext());
2489 if (Pred == ICmpInst::ICMP_EQ)
2490 return ConstantInt::getFalse(RHSC->getContext());
2491 if (Pred == ICmpInst::ICMP_NE)
2492 return ConstantInt::getTrue(RHSC->getContext());
2494 if (RHSC->getValue().isNonNegative()) {
2495 if (Pred == ICmpInst::ICMP_SLE)
2496 return ConstantInt::getTrue(RHSC->getContext());
2497 if (Pred == ICmpInst::ICMP_SGT)
2498 return ConstantInt::getFalse(RHSC->getContext());
2503 // icmp pred (urem X, Y), Y
2504 if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
2505 bool KnownNonNegative, KnownNegative;
2509 case ICmpInst::ICMP_SGT:
2510 case ICmpInst::ICMP_SGE:
2511 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.DL,
2512 0, Q.AT, Q.CxtI, Q.DT);
2513 if (!KnownNonNegative)
2516 case ICmpInst::ICMP_EQ:
2517 case ICmpInst::ICMP_UGT:
2518 case ICmpInst::ICMP_UGE:
2519 return getFalse(ITy);
2520 case ICmpInst::ICMP_SLT:
2521 case ICmpInst::ICMP_SLE:
2522 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.DL,
2523 0, Q.AT, Q.CxtI, Q.DT);
2524 if (!KnownNonNegative)
2527 case ICmpInst::ICMP_NE:
2528 case ICmpInst::ICMP_ULT:
2529 case ICmpInst::ICMP_ULE:
2530 return getTrue(ITy);
2534 // icmp pred X, (urem Y, X)
2535 if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
2536 bool KnownNonNegative, KnownNegative;
2540 case ICmpInst::ICMP_SGT:
2541 case ICmpInst::ICMP_SGE:
2542 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.DL,
2543 0, Q.AT, Q.CxtI, Q.DT);
2544 if (!KnownNonNegative)
2547 case ICmpInst::ICMP_NE:
2548 case ICmpInst::ICMP_UGT:
2549 case ICmpInst::ICMP_UGE:
2550 return getTrue(ITy);
2551 case ICmpInst::ICMP_SLT:
2552 case ICmpInst::ICMP_SLE:
2553 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.DL,
2554 0, Q.AT, Q.CxtI, Q.DT);
2555 if (!KnownNonNegative)
2558 case ICmpInst::ICMP_EQ:
2559 case ICmpInst::ICMP_ULT:
2560 case ICmpInst::ICMP_ULE:
2561 return getFalse(ITy);
2566 if (LBO && match(LBO, m_UDiv(m_Specific(RHS), m_Value()))) {
2567 // icmp pred (X /u Y), X
2568 if (Pred == ICmpInst::ICMP_UGT)
2569 return getFalse(ITy);
2570 if (Pred == ICmpInst::ICMP_ULE)
2571 return getTrue(ITy);
2578 // where CI2 is a power of 2 and CI isn't
2579 if (auto *CI = dyn_cast<ConstantInt>(RHS)) {
2580 const APInt *CI2Val, *CIVal = &CI->getValue();
2581 if (LBO && match(LBO, m_Shl(m_APInt(CI2Val), m_Value())) &&
2582 CI2Val->isPowerOf2()) {
2583 if (!CIVal->isPowerOf2()) {
2584 // CI2 << X can equal zero in some circumstances,
2585 // this simplification is unsafe if CI is zero.
2587 // We know it is safe if:
2588 // - The shift is nsw, we can't shift out the one bit.
2589 // - The shift is nuw, we can't shift out the one bit.
2592 if (LBO->hasNoSignedWrap() || LBO->hasNoUnsignedWrap() ||
2593 *CI2Val == 1 || !CI->isZero()) {
2594 if (Pred == ICmpInst::ICMP_EQ)
2595 return ConstantInt::getFalse(RHS->getContext());
2596 if (Pred == ICmpInst::ICMP_NE)
2597 return ConstantInt::getTrue(RHS->getContext());
2600 if (CIVal->isSignBit() && *CI2Val == 1) {
2601 if (Pred == ICmpInst::ICMP_UGT)
2602 return ConstantInt::getFalse(RHS->getContext());
2603 if (Pred == ICmpInst::ICMP_ULE)
2604 return ConstantInt::getTrue(RHS->getContext());
2609 if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
2610 LBO->getOperand(1) == RBO->getOperand(1)) {
2611 switch (LBO->getOpcode()) {
2613 case Instruction::UDiv:
2614 case Instruction::LShr:
2615 if (ICmpInst::isSigned(Pred))
2618 case Instruction::SDiv:
2619 case Instruction::AShr:
2620 if (!LBO->isExact() || !RBO->isExact())
2622 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2623 RBO->getOperand(0), Q, MaxRecurse-1))
2626 case Instruction::Shl: {
2627 bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
2628 bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
2631 if (!NSW && ICmpInst::isSigned(Pred))
2633 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2634 RBO->getOperand(0), Q, MaxRecurse-1))
2641 // Simplify comparisons involving max/min.
2643 CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE;
2644 CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
2646 // Signed variants on "max(a,b)>=a -> true".
2647 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2648 if (A != RHS) std::swap(A, B); // smax(A, B) pred A.
2649 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2650 // We analyze this as smax(A, B) pred A.
2652 } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
2653 (A == LHS || B == LHS)) {
2654 if (A != LHS) std::swap(A, B); // A pred smax(A, B).
2655 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2656 // We analyze this as smax(A, B) swapped-pred A.
2657 P = CmpInst::getSwappedPredicate(Pred);
2658 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2659 (A == RHS || B == RHS)) {
2660 if (A != RHS) std::swap(A, B); // smin(A, B) pred A.
2661 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2662 // We analyze this as smax(-A, -B) swapped-pred -A.
2663 // Note that we do not need to actually form -A or -B thanks to EqP.
2664 P = CmpInst::getSwappedPredicate(Pred);
2665 } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
2666 (A == LHS || B == LHS)) {
2667 if (A != LHS) std::swap(A, B); // A pred smin(A, B).
2668 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2669 // We analyze this as smax(-A, -B) pred -A.
2670 // Note that we do not need to actually form -A or -B thanks to EqP.
2673 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2674 // Cases correspond to "max(A, B) p A".
2678 case CmpInst::ICMP_EQ:
2679 case CmpInst::ICMP_SLE:
2680 // Equivalent to "A EqP B". This may be the same as the condition tested
2681 // in the max/min; if so, we can just return that.
2682 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2684 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2686 // Otherwise, see if "A EqP B" simplifies.
2688 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2691 case CmpInst::ICMP_NE:
2692 case CmpInst::ICMP_SGT: {
2693 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2694 // Equivalent to "A InvEqP B". This may be the same as the condition
2695 // tested in the max/min; if so, we can just return that.
2696 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2698 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2700 // Otherwise, see if "A InvEqP B" simplifies.
2702 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2706 case CmpInst::ICMP_SGE:
2708 return getTrue(ITy);
2709 case CmpInst::ICMP_SLT:
2711 return getFalse(ITy);
2715 // Unsigned variants on "max(a,b)>=a -> true".
2716 P = CmpInst::BAD_ICMP_PREDICATE;
2717 if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2718 if (A != RHS) std::swap(A, B); // umax(A, B) pred A.
2719 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2720 // We analyze this as umax(A, B) pred A.
2722 } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
2723 (A == LHS || B == LHS)) {
2724 if (A != LHS) std::swap(A, B); // A pred umax(A, B).
2725 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2726 // We analyze this as umax(A, B) swapped-pred A.
2727 P = CmpInst::getSwappedPredicate(Pred);
2728 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2729 (A == RHS || B == RHS)) {
2730 if (A != RHS) std::swap(A, B); // umin(A, B) pred A.
2731 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2732 // We analyze this as umax(-A, -B) swapped-pred -A.
2733 // Note that we do not need to actually form -A or -B thanks to EqP.
2734 P = CmpInst::getSwappedPredicate(Pred);
2735 } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
2736 (A == LHS || B == LHS)) {
2737 if (A != LHS) std::swap(A, B); // A pred umin(A, B).
2738 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2739 // We analyze this as umax(-A, -B) pred -A.
2740 // Note that we do not need to actually form -A or -B thanks to EqP.
2743 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2744 // Cases correspond to "max(A, B) p A".
2748 case CmpInst::ICMP_EQ:
2749 case CmpInst::ICMP_ULE:
2750 // Equivalent to "A EqP B". This may be the same as the condition tested
2751 // in the max/min; if so, we can just return that.
2752 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2754 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2756 // Otherwise, see if "A EqP B" simplifies.
2758 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2761 case CmpInst::ICMP_NE:
2762 case CmpInst::ICMP_UGT: {
2763 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2764 // Equivalent to "A InvEqP B". This may be the same as the condition
2765 // tested in the max/min; if so, we can just return that.
2766 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2768 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2770 // Otherwise, see if "A InvEqP B" simplifies.
2772 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2776 case CmpInst::ICMP_UGE:
2778 return getTrue(ITy);
2779 case CmpInst::ICMP_ULT:
2781 return getFalse(ITy);
2785 // Variants on "max(x,y) >= min(x,z)".
2787 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
2788 match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
2789 (A == C || A == D || B == C || B == D)) {
2790 // max(x, ?) pred min(x, ?).
2791 if (Pred == CmpInst::ICMP_SGE)
2793 return getTrue(ITy);
2794 if (Pred == CmpInst::ICMP_SLT)
2796 return getFalse(ITy);
2797 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2798 match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
2799 (A == C || A == D || B == C || B == D)) {
2800 // min(x, ?) pred max(x, ?).
2801 if (Pred == CmpInst::ICMP_SLE)
2803 return getTrue(ITy);
2804 if (Pred == CmpInst::ICMP_SGT)
2806 return getFalse(ITy);
2807 } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
2808 match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
2809 (A == C || A == D || B == C || B == D)) {
2810 // max(x, ?) pred min(x, ?).
2811 if (Pred == CmpInst::ICMP_UGE)
2813 return getTrue(ITy);
2814 if (Pred == CmpInst::ICMP_ULT)
2816 return getFalse(ITy);
2817 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2818 match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
2819 (A == C || A == D || B == C || B == D)) {
2820 // min(x, ?) pred max(x, ?).
2821 if (Pred == CmpInst::ICMP_ULE)
2823 return getTrue(ITy);
2824 if (Pred == CmpInst::ICMP_UGT)
2826 return getFalse(ITy);
2829 // Simplify comparisons of related pointers using a powerful, recursive
2830 // GEP-walk when we have target data available..
2831 if (LHS->getType()->isPointerTy())
2832 if (Constant *C = computePointerICmp(Q.DL, Q.TLI, Pred, LHS, RHS))
2835 if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
2836 if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
2837 if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
2838 GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
2839 (ICmpInst::isEquality(Pred) ||
2840 (GLHS->isInBounds() && GRHS->isInBounds() &&
2841 Pred == ICmpInst::getSignedPredicate(Pred)))) {
2842 // The bases are equal and the indices are constant. Build a constant
2843 // expression GEP with the same indices and a null base pointer to see
2844 // what constant folding can make out of it.
2845 Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
2846 SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
2847 Constant *NewLHS = ConstantExpr::getGetElementPtr(Null, IndicesLHS);
2849 SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
2850 Constant *NewRHS = ConstantExpr::getGetElementPtr(Null, IndicesRHS);
2851 return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
2856 // If the comparison is with the result of a select instruction, check whether
2857 // comparing with either branch of the select always yields the same value.
2858 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2859 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
2862 // If the comparison is with the result of a phi instruction, check whether
2863 // doing the compare with each incoming phi value yields a common result.
2864 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2865 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
2871 Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2872 const DataLayout *DL,
2873 const TargetLibraryInfo *TLI,
2874 const DominatorTree *DT,
2875 AssumptionTracker *AT,
2876 Instruction *CxtI) {
2877 return ::SimplifyICmpInst(Predicate, LHS, RHS, Query (DL, TLI, DT, AT, CxtI),
2881 /// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can
2882 /// fold the result. If not, this returns null.
2883 static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2884 const Query &Q, unsigned MaxRecurse) {
2885 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
2886 assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
2888 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
2889 if (Constant *CRHS = dyn_cast<Constant>(RHS))
2890 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
2892 // If we have a constant, make sure it is on the RHS.
2893 std::swap(LHS, RHS);
2894 Pred = CmpInst::getSwappedPredicate(Pred);
2897 // Fold trivial predicates.
2898 if (Pred == FCmpInst::FCMP_FALSE)
2899 return ConstantInt::get(GetCompareTy(LHS), 0);
2900 if (Pred == FCmpInst::FCMP_TRUE)
2901 return ConstantInt::get(GetCompareTy(LHS), 1);
2903 if (isa<UndefValue>(RHS)) // fcmp pred X, undef -> undef
2904 return UndefValue::get(GetCompareTy(LHS));
2906 // fcmp x,x -> true/false. Not all compares are foldable.
2908 if (CmpInst::isTrueWhenEqual(Pred))
2909 return ConstantInt::get(GetCompareTy(LHS), 1);
2910 if (CmpInst::isFalseWhenEqual(Pred))
2911 return ConstantInt::get(GetCompareTy(LHS), 0);
2914 // Handle fcmp with constant RHS
2915 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
2916 // If the constant is a nan, see if we can fold the comparison based on it.
2917 if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHSC)) {
2918 if (CFP->getValueAPF().isNaN()) {
2919 if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo"
2920 return ConstantInt::getFalse(CFP->getContext());
2921 assert(FCmpInst::isUnordered(Pred) &&
2922 "Comparison must be either ordered or unordered!");
2923 // True if unordered.
2924 return ConstantInt::getTrue(CFP->getContext());
2926 // Check whether the constant is an infinity.
2927 if (CFP->getValueAPF().isInfinity()) {
2928 if (CFP->getValueAPF().isNegative()) {
2930 case FCmpInst::FCMP_OLT:
2931 // No value is ordered and less than negative infinity.
2932 return ConstantInt::getFalse(CFP->getContext());
2933 case FCmpInst::FCMP_UGE:
2934 // All values are unordered with or at least negative infinity.
2935 return ConstantInt::getTrue(CFP->getContext());
2941 case FCmpInst::FCMP_OGT:
2942 // No value is ordered and greater than infinity.
2943 return ConstantInt::getFalse(CFP->getContext());
2944 case FCmpInst::FCMP_ULE:
2945 // All values are unordered with and at most infinity.
2946 return ConstantInt::getTrue(CFP->getContext());
2955 // If the comparison is with the result of a select instruction, check whether
2956 // comparing with either branch of the select always yields the same value.
2957 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2958 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
2961 // If the comparison is with the result of a phi instruction, check whether
2962 // doing the compare with each incoming phi value yields a common result.
2963 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2964 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
2970 Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2971 const DataLayout *DL,
2972 const TargetLibraryInfo *TLI,
2973 const DominatorTree *DT,
2974 AssumptionTracker *AT,
2975 const Instruction *CxtI) {
2976 return ::SimplifyFCmpInst(Predicate, LHS, RHS, Query (DL, TLI, DT, AT, CxtI),
2980 /// SimplifySelectInst - Given operands for a SelectInst, see if we can fold
2981 /// the result. If not, this returns null.
2982 static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal,
2983 Value *FalseVal, const Query &Q,
2984 unsigned MaxRecurse) {
2985 // select true, X, Y -> X
2986 // select false, X, Y -> Y
2987 if (Constant *CB = dyn_cast<Constant>(CondVal)) {
2988 if (CB->isAllOnesValue())
2990 if (CB->isNullValue())
2994 // select C, X, X -> X
2995 if (TrueVal == FalseVal)
2998 if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y
2999 if (isa<Constant>(TrueVal))
3003 if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X
3005 if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
3011 Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
3012 const DataLayout *DL,
3013 const TargetLibraryInfo *TLI,
3014 const DominatorTree *DT,
3015 AssumptionTracker *AT,
3016 const Instruction *CxtI) {
3017 return ::SimplifySelectInst(Cond, TrueVal, FalseVal,
3018 Query (DL, TLI, DT, AT, CxtI), RecursionLimit);
3021 /// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
3022 /// fold the result. If not, this returns null.
3023 static Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const Query &Q, unsigned) {
3024 // The type of the GEP pointer operand.
3025 PointerType *PtrTy = cast<PointerType>(Ops[0]->getType()->getScalarType());
3026 unsigned AS = PtrTy->getAddressSpace();
3028 // getelementptr P -> P.
3029 if (Ops.size() == 1)
3032 // Compute the (pointer) type returned by the GEP instruction.
3033 Type *LastType = GetElementPtrInst::getIndexedType(PtrTy, Ops.slice(1));
3034 Type *GEPTy = PointerType::get(LastType, AS);
3035 if (VectorType *VT = dyn_cast<VectorType>(Ops[0]->getType()))
3036 GEPTy = VectorType::get(GEPTy, VT->getNumElements());
3038 if (isa<UndefValue>(Ops[0]))
3039 return UndefValue::get(GEPTy);
3041 if (Ops.size() == 2) {
3042 // getelementptr P, 0 -> P.
3043 if (match(Ops[1], m_Zero()))
3046 Type *Ty = PtrTy->getElementType();
3047 if (Q.DL && Ty->isSized()) {
3050 uint64_t TyAllocSize = Q.DL->getTypeAllocSize(Ty);
3051 // getelementptr P, N -> P if P points to a type of zero size.
3052 if (TyAllocSize == 0)
3055 // The following transforms are only safe if the ptrtoint cast
3056 // doesn't truncate the pointers.
3057 if (Ops[1]->getType()->getScalarSizeInBits() ==
3058 Q.DL->getPointerSizeInBits(AS)) {
3059 auto PtrToIntOrZero = [GEPTy](Value *P) -> Value * {
3060 if (match(P, m_Zero()))
3061 return Constant::getNullValue(GEPTy);
3063 if (match(P, m_PtrToInt(m_Value(Temp))))
3064 if (Temp->getType() == GEPTy)
3069 // getelementptr V, (sub P, V) -> P if P points to a type of size 1.
3070 if (TyAllocSize == 1 &&
3071 match(Ops[1], m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0])))))
3072 if (Value *R = PtrToIntOrZero(P))
3075 // getelementptr V, (ashr (sub P, V), C) -> Q
3076 // if P points to a type of size 1 << C.
3078 m_AShr(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3079 m_ConstantInt(C))) &&
3080 TyAllocSize == 1ULL << C)
3081 if (Value *R = PtrToIntOrZero(P))
3084 // getelementptr V, (sdiv (sub P, V), C) -> Q
3085 // if P points to a type of size C.
3087 m_SDiv(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3088 m_SpecificInt(TyAllocSize))))
3089 if (Value *R = PtrToIntOrZero(P))
3095 // Check to see if this is constant foldable.
3096 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
3097 if (!isa<Constant>(Ops[i]))
3100 return ConstantExpr::getGetElementPtr(cast<Constant>(Ops[0]), Ops.slice(1));
3103 Value *llvm::SimplifyGEPInst(ArrayRef<Value *> Ops, const DataLayout *DL,
3104 const TargetLibraryInfo *TLI,
3105 const DominatorTree *DT, AssumptionTracker *AT,
3106 const Instruction *CxtI) {
3107 return ::SimplifyGEPInst(Ops, Query (DL, TLI, DT, AT, CxtI), RecursionLimit);
3110 /// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we
3111 /// can fold the result. If not, this returns null.
3112 static Value *SimplifyInsertValueInst(Value *Agg, Value *Val,
3113 ArrayRef<unsigned> Idxs, const Query &Q,
3115 if (Constant *CAgg = dyn_cast<Constant>(Agg))
3116 if (Constant *CVal = dyn_cast<Constant>(Val))
3117 return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
3119 // insertvalue x, undef, n -> x
3120 if (match(Val, m_Undef()))
3123 // insertvalue x, (extractvalue y, n), n
3124 if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
3125 if (EV->getAggregateOperand()->getType() == Agg->getType() &&
3126 EV->getIndices() == Idxs) {
3127 // insertvalue undef, (extractvalue y, n), n -> y
3128 if (match(Agg, m_Undef()))
3129 return EV->getAggregateOperand();
3131 // insertvalue y, (extractvalue y, n), n -> y
3132 if (Agg == EV->getAggregateOperand())
3139 Value *llvm::SimplifyInsertValueInst(Value *Agg, Value *Val,
3140 ArrayRef<unsigned> Idxs,
3141 const DataLayout *DL,
3142 const TargetLibraryInfo *TLI,
3143 const DominatorTree *DT,
3144 AssumptionTracker *AT,
3145 const Instruction *CxtI) {
3146 return ::SimplifyInsertValueInst(Agg, Val, Idxs,
3147 Query (DL, TLI, DT, AT, CxtI),
3151 /// SimplifyPHINode - See if we can fold the given phi. If not, returns null.
3152 static Value *SimplifyPHINode(PHINode *PN, const Query &Q) {
3153 // If all of the PHI's incoming values are the same then replace the PHI node
3154 // with the common value.
3155 Value *CommonValue = nullptr;
3156 bool HasUndefInput = false;
3157 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
3158 Value *Incoming = PN->getIncomingValue(i);
3159 // If the incoming value is the phi node itself, it can safely be skipped.
3160 if (Incoming == PN) continue;
3161 if (isa<UndefValue>(Incoming)) {
3162 // Remember that we saw an undef value, but otherwise ignore them.
3163 HasUndefInput = true;
3166 if (CommonValue && Incoming != CommonValue)
3167 return nullptr; // Not the same, bail out.
3168 CommonValue = Incoming;
3171 // If CommonValue is null then all of the incoming values were either undef or
3172 // equal to the phi node itself.
3174 return UndefValue::get(PN->getType());
3176 // If we have a PHI node like phi(X, undef, X), where X is defined by some
3177 // instruction, we cannot return X as the result of the PHI node unless it
3178 // dominates the PHI block.
3180 return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : nullptr;
3185 static Value *SimplifyTruncInst(Value *Op, Type *Ty, const Query &Q, unsigned) {
3186 if (Constant *C = dyn_cast<Constant>(Op))
3187 return ConstantFoldInstOperands(Instruction::Trunc, Ty, C, Q.DL, Q.TLI);
3192 Value *llvm::SimplifyTruncInst(Value *Op, Type *Ty, const DataLayout *DL,
3193 const TargetLibraryInfo *TLI,
3194 const DominatorTree *DT,
3195 AssumptionTracker *AT,
3196 const Instruction *CxtI) {
3197 return ::SimplifyTruncInst(Op, Ty, Query (DL, TLI, DT, AT, CxtI),
3201 //=== Helper functions for higher up the class hierarchy.
3203 /// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
3204 /// fold the result. If not, this returns null.
3205 static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
3206 const Query &Q, unsigned MaxRecurse) {
3208 case Instruction::Add:
3209 return SimplifyAddInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
3211 case Instruction::FAdd:
3212 return SimplifyFAddInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3214 case Instruction::Sub:
3215 return SimplifySubInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
3217 case Instruction::FSub:
3218 return SimplifyFSubInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3220 case Instruction::Mul: return SimplifyMulInst (LHS, RHS, Q, MaxRecurse);
3221 case Instruction::FMul:
3222 return SimplifyFMulInst (LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3223 case Instruction::SDiv: return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
3224 case Instruction::UDiv: return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
3225 case Instruction::FDiv: return SimplifyFDivInst(LHS, RHS, Q, MaxRecurse);
3226 case Instruction::SRem: return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
3227 case Instruction::URem: return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
3228 case Instruction::FRem: return SimplifyFRemInst(LHS, RHS, Q, MaxRecurse);
3229 case Instruction::Shl:
3230 return SimplifyShlInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
3232 case Instruction::LShr:
3233 return SimplifyLShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
3234 case Instruction::AShr:
3235 return SimplifyAShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
3236 case Instruction::And: return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
3237 case Instruction::Or: return SimplifyOrInst (LHS, RHS, Q, MaxRecurse);
3238 case Instruction::Xor: return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
3240 if (Constant *CLHS = dyn_cast<Constant>(LHS))
3241 if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
3242 Constant *COps[] = {CLHS, CRHS};
3243 return ConstantFoldInstOperands(Opcode, LHS->getType(), COps, Q.DL,
3247 // If the operation is associative, try some generic simplifications.
3248 if (Instruction::isAssociative(Opcode))
3249 if (Value *V = SimplifyAssociativeBinOp(Opcode, LHS, RHS, Q, MaxRecurse))
3252 // If the operation is with the result of a select instruction check whether
3253 // operating on either branch of the select always yields the same value.
3254 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3255 if (Value *V = ThreadBinOpOverSelect(Opcode, LHS, RHS, Q, MaxRecurse))
3258 // If the operation is with the result of a phi instruction, check whether
3259 // operating on all incoming values of the phi always yields the same value.
3260 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3261 if (Value *V = ThreadBinOpOverPHI(Opcode, LHS, RHS, Q, MaxRecurse))
3268 Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
3269 const DataLayout *DL, const TargetLibraryInfo *TLI,
3270 const DominatorTree *DT, AssumptionTracker *AT,
3271 const Instruction *CxtI) {
3272 return ::SimplifyBinOp(Opcode, LHS, RHS, Query (DL, TLI, DT, AT, CxtI),
3276 /// SimplifyCmpInst - Given operands for a CmpInst, see if we can
3277 /// fold the result.
3278 static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3279 const Query &Q, unsigned MaxRecurse) {
3280 if (CmpInst::isIntPredicate((CmpInst::Predicate)Predicate))
3281 return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
3282 return SimplifyFCmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
3285 Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3286 const DataLayout *DL, const TargetLibraryInfo *TLI,
3287 const DominatorTree *DT, AssumptionTracker *AT,
3288 const Instruction *CxtI) {
3289 return ::SimplifyCmpInst(Predicate, LHS, RHS, Query (DL, TLI, DT, AT, CxtI),
3293 static bool IsIdempotent(Intrinsic::ID ID) {
3295 default: return false;
3297 // Unary idempotent: f(f(x)) = f(x)
3298 case Intrinsic::fabs:
3299 case Intrinsic::floor:
3300 case Intrinsic::ceil:
3301 case Intrinsic::trunc:
3302 case Intrinsic::rint:
3303 case Intrinsic::nearbyint:
3304 case Intrinsic::round:
3309 template <typename IterTy>
3310 static Value *SimplifyIntrinsic(Intrinsic::ID IID, IterTy ArgBegin, IterTy ArgEnd,
3311 const Query &Q, unsigned MaxRecurse) {
3312 // Perform idempotent optimizations
3313 if (!IsIdempotent(IID))
3317 if (std::distance(ArgBegin, ArgEnd) == 1)
3318 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(*ArgBegin))
3319 if (II->getIntrinsicID() == IID)
3325 template <typename IterTy>
3326 static Value *SimplifyCall(Value *V, IterTy ArgBegin, IterTy ArgEnd,
3327 const Query &Q, unsigned MaxRecurse) {
3328 Type *Ty = V->getType();
3329 if (PointerType *PTy = dyn_cast<PointerType>(Ty))
3330 Ty = PTy->getElementType();
3331 FunctionType *FTy = cast<FunctionType>(Ty);
3333 // call undef -> undef
3334 if (isa<UndefValue>(V))
3335 return UndefValue::get(FTy->getReturnType());
3337 Function *F = dyn_cast<Function>(V);
3341 if (unsigned IID = F->getIntrinsicID())
3343 SimplifyIntrinsic((Intrinsic::ID) IID, ArgBegin, ArgEnd, Q, MaxRecurse))
3346 if (!canConstantFoldCallTo(F))
3349 SmallVector<Constant *, 4> ConstantArgs;
3350 ConstantArgs.reserve(ArgEnd - ArgBegin);
3351 for (IterTy I = ArgBegin, E = ArgEnd; I != E; ++I) {
3352 Constant *C = dyn_cast<Constant>(*I);
3355 ConstantArgs.push_back(C);
3358 return ConstantFoldCall(F, ConstantArgs, Q.TLI);
3361 Value *llvm::SimplifyCall(Value *V, User::op_iterator ArgBegin,
3362 User::op_iterator ArgEnd, const DataLayout *DL,
3363 const TargetLibraryInfo *TLI,
3364 const DominatorTree *DT, AssumptionTracker *AT,
3365 const Instruction *CxtI) {
3366 return ::SimplifyCall(V, ArgBegin, ArgEnd, Query(DL, TLI, DT, AT, CxtI),
3370 Value *llvm::SimplifyCall(Value *V, ArrayRef<Value *> Args,
3371 const DataLayout *DL, const TargetLibraryInfo *TLI,
3372 const DominatorTree *DT, AssumptionTracker *AT,
3373 const Instruction *CxtI) {
3374 return ::SimplifyCall(V, Args.begin(), Args.end(),
3375 Query(DL, TLI, DT, AT, CxtI), RecursionLimit);
3378 /// SimplifyInstruction - See if we can compute a simplified version of this
3379 /// instruction. If not, this returns null.
3380 Value *llvm::SimplifyInstruction(Instruction *I, const DataLayout *DL,
3381 const TargetLibraryInfo *TLI,
3382 const DominatorTree *DT,
3383 AssumptionTracker *AT) {
3386 switch (I->getOpcode()) {
3388 Result = ConstantFoldInstruction(I, DL, TLI);
3390 case Instruction::FAdd:
3391 Result = SimplifyFAddInst(I->getOperand(0), I->getOperand(1),
3392 I->getFastMathFlags(), DL, TLI, DT, AT, I);
3394 case Instruction::Add:
3395 Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
3396 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3397 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3398 DL, TLI, DT, AT, I);
3400 case Instruction::FSub:
3401 Result = SimplifyFSubInst(I->getOperand(0), I->getOperand(1),
3402 I->getFastMathFlags(), DL, TLI, DT, AT, I);
3404 case Instruction::Sub:
3405 Result = SimplifySubInst(I->getOperand(0), I->getOperand(1),
3406 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3407 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3408 DL, TLI, DT, AT, I);
3410 case Instruction::FMul:
3411 Result = SimplifyFMulInst(I->getOperand(0), I->getOperand(1),
3412 I->getFastMathFlags(), DL, TLI, DT, AT, I);
3414 case Instruction::Mul:
3415 Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1),
3416 DL, TLI, DT, AT, I);
3418 case Instruction::SDiv:
3419 Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1),
3420 DL, TLI, DT, AT, I);
3422 case Instruction::UDiv:
3423 Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1),
3424 DL, TLI, DT, AT, I);
3426 case Instruction::FDiv:
3427 Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1),
3428 DL, TLI, DT, AT, I);
3430 case Instruction::SRem:
3431 Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1),
3432 DL, TLI, DT, AT, I);
3434 case Instruction::URem:
3435 Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1),
3436 DL, TLI, DT, AT, I);
3438 case Instruction::FRem:
3439 Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1),
3440 DL, TLI, DT, AT, I);
3442 case Instruction::Shl:
3443 Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1),
3444 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3445 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3446 DL, TLI, DT, AT, I);
3448 case Instruction::LShr:
3449 Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
3450 cast<BinaryOperator>(I)->isExact(),
3451 DL, TLI, DT, AT, I);
3453 case Instruction::AShr:
3454 Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
3455 cast<BinaryOperator>(I)->isExact(),
3456 DL, TLI, DT, AT, I);
3458 case Instruction::And:
3459 Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1),
3460 DL, TLI, DT, AT, I);
3462 case Instruction::Or:
3463 Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT,
3466 case Instruction::Xor:
3467 Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1),
3468 DL, TLI, DT, AT, I);
3470 case Instruction::ICmp:
3471 Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
3472 I->getOperand(0), I->getOperand(1),
3473 DL, TLI, DT, AT, I);
3475 case Instruction::FCmp:
3476 Result = SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(),
3477 I->getOperand(0), I->getOperand(1),
3478 DL, TLI, DT, AT, I);
3480 case Instruction::Select:
3481 Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
3482 I->getOperand(2), DL, TLI, DT, AT, I);
3484 case Instruction::GetElementPtr: {
3485 SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end());
3486 Result = SimplifyGEPInst(Ops, DL, TLI, DT, AT, I);
3489 case Instruction::InsertValue: {
3490 InsertValueInst *IV = cast<InsertValueInst>(I);
3491 Result = SimplifyInsertValueInst(IV->getAggregateOperand(),
3492 IV->getInsertedValueOperand(),
3493 IV->getIndices(), DL, TLI, DT, AT, I);
3496 case Instruction::PHI:
3497 Result = SimplifyPHINode(cast<PHINode>(I), Query (DL, TLI, DT, AT, I));
3499 case Instruction::Call: {
3500 CallSite CS(cast<CallInst>(I));
3501 Result = SimplifyCall(CS.getCalledValue(), CS.arg_begin(), CS.arg_end(),
3502 DL, TLI, DT, AT, I);
3505 case Instruction::Trunc:
3506 Result = SimplifyTruncInst(I->getOperand(0), I->getType(), DL, TLI, DT,
3511 /// If called on unreachable code, the above logic may report that the
3512 /// instruction simplified to itself. Make life easier for users by
3513 /// detecting that case here, returning a safe value instead.
3514 return Result == I ? UndefValue::get(I->getType()) : Result;
3517 /// \brief Implementation of recursive simplification through an instructions
3520 /// This is the common implementation of the recursive simplification routines.
3521 /// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
3522 /// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
3523 /// instructions to process and attempt to simplify it using
3524 /// InstructionSimplify.
3526 /// This routine returns 'true' only when *it* simplifies something. The passed
3527 /// in simplified value does not count toward this.
3528 static bool replaceAndRecursivelySimplifyImpl(Instruction *I, Value *SimpleV,
3529 const DataLayout *DL,
3530 const TargetLibraryInfo *TLI,
3531 const DominatorTree *DT,
3532 AssumptionTracker *AT) {
3533 bool Simplified = false;
3534 SmallSetVector<Instruction *, 8> Worklist;
3536 // If we have an explicit value to collapse to, do that round of the
3537 // simplification loop by hand initially.
3539 for (User *U : I->users())
3541 Worklist.insert(cast<Instruction>(U));
3543 // Replace the instruction with its simplified value.
3544 I->replaceAllUsesWith(SimpleV);
3546 // Gracefully handle edge cases where the instruction is not wired into any
3549 I->eraseFromParent();
3554 // Note that we must test the size on each iteration, the worklist can grow.
3555 for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
3558 // See if this instruction simplifies.
3559 SimpleV = SimplifyInstruction(I, DL, TLI, DT, AT);
3565 // Stash away all the uses of the old instruction so we can check them for
3566 // recursive simplifications after a RAUW. This is cheaper than checking all
3567 // uses of To on the recursive step in most cases.
3568 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 bool llvm::recursivelySimplifyInstruction(Instruction *I,
3583 const DataLayout *DL,
3584 const TargetLibraryInfo *TLI,
3585 const DominatorTree *DT,
3586 AssumptionTracker *AT) {
3587 return replaceAndRecursivelySimplifyImpl(I, nullptr, DL, TLI, DT, AT);
3590 bool llvm::replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV,
3591 const DataLayout *DL,
3592 const TargetLibraryInfo *TLI,
3593 const DominatorTree *DT,
3594 AssumptionTracker *AT) {
3595 assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!");
3596 assert(SimpleV && "Must provide a simplified value.");
3597 return replaceAndRecursivelySimplifyImpl(I, SimpleV, DL, TLI, DT, AT);