1 //===- InstructionSimplify.cpp - Fold instruction operands ----------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements routines for folding instructions into simpler forms
11 // that do not require creating new instructions. This does constant folding
12 // ("add i32 1, 1" -> "2") but can also handle non-constant operands, either
13 // returning a constant ("and i32 %x, 0" -> "0") or an already existing value
14 // ("and i32 %x, %x" -> "%x"). All operands are assumed to have already been
15 // simplified: This is usually true and assuming it simplifies the logic (if
16 // they have not been simplified then results are correct but maybe suboptimal).
18 //===----------------------------------------------------------------------===//
20 #include "llvm/Analysis/InstructionSimplify.h"
21 #include "llvm/ADT/SetVector.h"
22 #include "llvm/ADT/Statistic.h"
23 #include "llvm/Analysis/AliasAnalysis.h"
24 #include "llvm/Analysis/ConstantFolding.h"
25 #include "llvm/Analysis/MemoryBuiltins.h"
26 #include "llvm/Analysis/ValueTracking.h"
27 #include "llvm/IR/ConstantRange.h"
28 #include "llvm/IR/DataLayout.h"
29 #include "llvm/IR/Dominators.h"
30 #include "llvm/IR/GetElementPtrTypeIterator.h"
31 #include "llvm/IR/GlobalAlias.h"
32 #include "llvm/IR/Operator.h"
33 #include "llvm/IR/PatternMatch.h"
34 #include "llvm/IR/ValueHandle.h"
37 using namespace llvm::PatternMatch;
39 #define DEBUG_TYPE "instsimplify"
41 enum { RecursionLimit = 3 };
43 STATISTIC(NumExpand, "Number of expansions");
44 STATISTIC(NumReassoc, "Number of reassociations");
49 const TargetLibraryInfo *TLI;
50 const DominatorTree *DT;
52 const Instruction *CxtI;
54 Query(const DataLayout *DL, const TargetLibraryInfo *tli,
55 const DominatorTree *dt, AssumptionCache *ac = nullptr,
56 const Instruction *cxti = nullptr)
57 : DL(DL), TLI(tli), DT(dt), AC(ac), CxtI(cxti) {}
59 } // end anonymous namespace
61 static Value *SimplifyAndInst(Value *, Value *, const Query &, unsigned);
62 static Value *SimplifyBinOp(unsigned, Value *, Value *, const Query &,
64 static Value *SimplifyFPBinOp(unsigned, Value *, Value *, const FastMathFlags &,
65 const Query &, unsigned);
66 static Value *SimplifyCmpInst(unsigned, Value *, Value *, const Query &,
68 static Value *SimplifyOrInst(Value *, Value *, const Query &, unsigned);
69 static Value *SimplifyXorInst(Value *, Value *, const Query &, unsigned);
70 static Value *SimplifyTruncInst(Value *, Type *, const Query &, unsigned);
72 /// getFalse - For a boolean type, or a vector of boolean type, return false, or
73 /// a vector with every element false, as appropriate for the type.
74 static Constant *getFalse(Type *Ty) {
75 assert(Ty->getScalarType()->isIntegerTy(1) &&
76 "Expected i1 type or a vector of i1!");
77 return Constant::getNullValue(Ty);
80 /// getTrue - For a boolean type, or a vector of boolean type, return true, or
81 /// a vector with every element true, as appropriate for the type.
82 static Constant *getTrue(Type *Ty) {
83 assert(Ty->getScalarType()->isIntegerTy(1) &&
84 "Expected i1 type or a vector of i1!");
85 return Constant::getAllOnesValue(Ty);
88 /// isSameCompare - Is V equivalent to the comparison "LHS Pred RHS"?
89 static bool isSameCompare(Value *V, CmpInst::Predicate Pred, Value *LHS,
91 CmpInst *Cmp = dyn_cast<CmpInst>(V);
94 CmpInst::Predicate CPred = Cmp->getPredicate();
95 Value *CLHS = Cmp->getOperand(0), *CRHS = Cmp->getOperand(1);
96 if (CPred == Pred && CLHS == LHS && CRHS == RHS)
98 return CPred == CmpInst::getSwappedPredicate(Pred) && CLHS == RHS &&
102 /// ValueDominatesPHI - Does the given value dominate the specified phi node?
103 static bool ValueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
104 Instruction *I = dyn_cast<Instruction>(V);
106 // Arguments and constants dominate all instructions.
109 // If we are processing instructions (and/or basic blocks) that have not been
110 // fully added to a function, the parent nodes may still be null. Simply
111 // return the conservative answer in these cases.
112 if (!I->getParent() || !P->getParent() || !I->getParent()->getParent())
115 // If we have a DominatorTree then do a precise test.
117 if (!DT->isReachableFromEntry(P->getParent()))
119 if (!DT->isReachableFromEntry(I->getParent()))
121 return DT->dominates(I, P);
124 // Otherwise, if the instruction is in the entry block, and is not an invoke,
125 // then it obviously dominates all phi nodes.
126 if (I->getParent() == &I->getParent()->getParent()->getEntryBlock() &&
133 /// ExpandBinOp - Simplify "A op (B op' C)" by distributing op over op', turning
134 /// it into "(A op B) op' (A op C)". Here "op" is given by Opcode and "op'" is
135 /// given by OpcodeToExpand, while "A" corresponds to LHS and "B op' C" to RHS.
136 /// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)".
137 /// Returns the simplified value, or null if no simplification was performed.
138 static Value *ExpandBinOp(unsigned Opcode, Value *LHS, Value *RHS,
139 unsigned OpcToExpand, const Query &Q,
140 unsigned MaxRecurse) {
141 Instruction::BinaryOps OpcodeToExpand = (Instruction::BinaryOps)OpcToExpand;
142 // Recursion is always used, so bail out at once if we already hit the limit.
146 // Check whether the expression has the form "(A op' B) op C".
147 if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS))
148 if (Op0->getOpcode() == OpcodeToExpand) {
149 // It does! Try turning it into "(A op C) op' (B op C)".
150 Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS;
151 // Do "A op C" and "B op C" both simplify?
152 if (Value *L = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse))
153 if (Value *R = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
154 // They do! Return "L op' R" if it simplifies or is already available.
155 // If "L op' R" equals "A op' B" then "L op' R" is just the LHS.
156 if ((L == A && R == B) || (Instruction::isCommutative(OpcodeToExpand)
157 && L == B && R == A)) {
161 // Otherwise return "L op' R" if it simplifies.
162 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
169 // Check whether the expression has the form "A op (B op' C)".
170 if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS))
171 if (Op1->getOpcode() == OpcodeToExpand) {
172 // It does! Try turning it into "(A op B) op' (A op C)".
173 Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1);
174 // Do "A op B" and "A op C" both simplify?
175 if (Value *L = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse))
176 if (Value *R = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse)) {
177 // They do! Return "L op' R" if it simplifies or is already available.
178 // If "L op' R" equals "B op' C" then "L op' R" is just the RHS.
179 if ((L == B && R == C) || (Instruction::isCommutative(OpcodeToExpand)
180 && L == C && R == B)) {
184 // Otherwise return "L op' R" if it simplifies.
185 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
195 /// SimplifyAssociativeBinOp - Generic simplifications for associative binary
196 /// operations. Returns the simpler value, or null if none was found.
197 static Value *SimplifyAssociativeBinOp(unsigned Opc, Value *LHS, Value *RHS,
198 const Query &Q, unsigned MaxRecurse) {
199 Instruction::BinaryOps Opcode = (Instruction::BinaryOps)Opc;
200 assert(Instruction::isAssociative(Opcode) && "Not an associative operation!");
202 // Recursion is always used, so bail out at once if we already hit the limit.
206 BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
207 BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
209 // Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely.
210 if (Op0 && Op0->getOpcode() == Opcode) {
211 Value *A = Op0->getOperand(0);
212 Value *B = Op0->getOperand(1);
215 // Does "B op C" simplify?
216 if (Value *V = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
217 // It does! Return "A op V" if it simplifies or is already available.
218 // If V equals B then "A op V" is just the LHS.
219 if (V == B) return LHS;
220 // Otherwise return "A op V" if it simplifies.
221 if (Value *W = SimplifyBinOp(Opcode, A, V, Q, MaxRecurse)) {
228 // Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely.
229 if (Op1 && Op1->getOpcode() == Opcode) {
231 Value *B = Op1->getOperand(0);
232 Value *C = Op1->getOperand(1);
234 // Does "A op B" simplify?
235 if (Value *V = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse)) {
236 // It does! Return "V op C" if it simplifies or is already available.
237 // If V equals B then "V op C" is just the RHS.
238 if (V == B) return RHS;
239 // Otherwise return "V op C" if it simplifies.
240 if (Value *W = SimplifyBinOp(Opcode, V, C, Q, MaxRecurse)) {
247 // The remaining transforms require commutativity as well as associativity.
248 if (!Instruction::isCommutative(Opcode))
251 // Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely.
252 if (Op0 && Op0->getOpcode() == Opcode) {
253 Value *A = Op0->getOperand(0);
254 Value *B = Op0->getOperand(1);
257 // Does "C op A" simplify?
258 if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
259 // It does! Return "V op B" if it simplifies or is already available.
260 // If V equals A then "V op B" is just the LHS.
261 if (V == A) return LHS;
262 // Otherwise return "V op B" if it simplifies.
263 if (Value *W = SimplifyBinOp(Opcode, V, B, Q, MaxRecurse)) {
270 // Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely.
271 if (Op1 && Op1->getOpcode() == Opcode) {
273 Value *B = Op1->getOperand(0);
274 Value *C = Op1->getOperand(1);
276 // Does "C op A" simplify?
277 if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
278 // It does! Return "B op V" if it simplifies or is already available.
279 // If V equals C then "B op V" is just the RHS.
280 if (V == C) return RHS;
281 // Otherwise return "B op V" if it simplifies.
282 if (Value *W = SimplifyBinOp(Opcode, B, V, Q, MaxRecurse)) {
292 /// ThreadBinOpOverSelect - In the case of a binary operation with a select
293 /// instruction as an operand, try to simplify the binop by seeing whether
294 /// evaluating it on both branches of the select results in the same value.
295 /// Returns the common value if so, otherwise returns null.
296 static Value *ThreadBinOpOverSelect(unsigned Opcode, Value *LHS, Value *RHS,
297 const Query &Q, unsigned MaxRecurse) {
298 // Recursion is always used, so bail out at once if we already hit the limit.
303 if (isa<SelectInst>(LHS)) {
304 SI = cast<SelectInst>(LHS);
306 assert(isa<SelectInst>(RHS) && "No select instruction operand!");
307 SI = cast<SelectInst>(RHS);
310 // Evaluate the BinOp on the true and false branches of the select.
314 TV = SimplifyBinOp(Opcode, SI->getTrueValue(), RHS, Q, MaxRecurse);
315 FV = SimplifyBinOp(Opcode, SI->getFalseValue(), RHS, Q, MaxRecurse);
317 TV = SimplifyBinOp(Opcode, LHS, SI->getTrueValue(), Q, MaxRecurse);
318 FV = SimplifyBinOp(Opcode, LHS, SI->getFalseValue(), Q, MaxRecurse);
321 // If they simplified to the same value, then return the common value.
322 // If they both failed to simplify then return null.
326 // If one branch simplified to undef, return the other one.
327 if (TV && isa<UndefValue>(TV))
329 if (FV && isa<UndefValue>(FV))
332 // If applying the operation did not change the true and false select values,
333 // then the result of the binop is the select itself.
334 if (TV == SI->getTrueValue() && FV == SI->getFalseValue())
337 // If one branch simplified and the other did not, and the simplified
338 // value is equal to the unsimplified one, return the simplified value.
339 // For example, select (cond, X, X & Z) & Z -> X & Z.
340 if ((FV && !TV) || (TV && !FV)) {
341 // Check that the simplified value has the form "X op Y" where "op" is the
342 // same as the original operation.
343 Instruction *Simplified = dyn_cast<Instruction>(FV ? FV : TV);
344 if (Simplified && Simplified->getOpcode() == Opcode) {
345 // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS".
346 // We already know that "op" is the same as for the simplified value. See
347 // if the operands match too. If so, return the simplified value.
348 Value *UnsimplifiedBranch = FV ? SI->getTrueValue() : SI->getFalseValue();
349 Value *UnsimplifiedLHS = SI == LHS ? UnsimplifiedBranch : LHS;
350 Value *UnsimplifiedRHS = SI == LHS ? RHS : UnsimplifiedBranch;
351 if (Simplified->getOperand(0) == UnsimplifiedLHS &&
352 Simplified->getOperand(1) == UnsimplifiedRHS)
354 if (Simplified->isCommutative() &&
355 Simplified->getOperand(1) == UnsimplifiedLHS &&
356 Simplified->getOperand(0) == UnsimplifiedRHS)
364 /// ThreadCmpOverSelect - In the case of a comparison with a select instruction,
365 /// try to simplify the comparison by seeing whether both branches of the select
366 /// result in the same value. Returns the common value if so, otherwise returns
368 static Value *ThreadCmpOverSelect(CmpInst::Predicate Pred, Value *LHS,
369 Value *RHS, const Query &Q,
370 unsigned MaxRecurse) {
371 // Recursion is always used, so bail out at once if we already hit the limit.
375 // Make sure the select is on the LHS.
376 if (!isa<SelectInst>(LHS)) {
378 Pred = CmpInst::getSwappedPredicate(Pred);
380 assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!");
381 SelectInst *SI = cast<SelectInst>(LHS);
382 Value *Cond = SI->getCondition();
383 Value *TV = SI->getTrueValue();
384 Value *FV = SI->getFalseValue();
386 // Now that we have "cmp select(Cond, TV, FV), RHS", analyse it.
387 // Does "cmp TV, RHS" simplify?
388 Value *TCmp = SimplifyCmpInst(Pred, TV, RHS, Q, MaxRecurse);
390 // It not only simplified, it simplified to the select condition. Replace
392 TCmp = getTrue(Cond->getType());
394 // It didn't simplify. However if "cmp TV, RHS" is equal to the select
395 // condition then we can replace it with 'true'. Otherwise give up.
396 if (!isSameCompare(Cond, Pred, TV, RHS))
398 TCmp = getTrue(Cond->getType());
401 // Does "cmp FV, RHS" simplify?
402 Value *FCmp = SimplifyCmpInst(Pred, FV, RHS, Q, MaxRecurse);
404 // It not only simplified, it simplified to the select condition. Replace
406 FCmp = getFalse(Cond->getType());
408 // It didn't simplify. However if "cmp FV, RHS" is equal to the select
409 // condition then we can replace it with 'false'. Otherwise give up.
410 if (!isSameCompare(Cond, Pred, FV, RHS))
412 FCmp = getFalse(Cond->getType());
415 // If both sides simplified to the same value, then use it as the result of
416 // the original comparison.
420 // The remaining cases only make sense if the select condition has the same
421 // type as the result of the comparison, so bail out if this is not so.
422 if (Cond->getType()->isVectorTy() != RHS->getType()->isVectorTy())
424 // If the false value simplified to false, then the result of the compare
425 // is equal to "Cond && TCmp". This also catches the case when the false
426 // value simplified to false and the true value to true, returning "Cond".
427 if (match(FCmp, m_Zero()))
428 if (Value *V = SimplifyAndInst(Cond, TCmp, Q, MaxRecurse))
430 // If the true value simplified to true, then the result of the compare
431 // is equal to "Cond || FCmp".
432 if (match(TCmp, m_One()))
433 if (Value *V = SimplifyOrInst(Cond, FCmp, Q, MaxRecurse))
435 // Finally, if the false value simplified to true and the true value to
436 // false, then the result of the compare is equal to "!Cond".
437 if (match(FCmp, m_One()) && match(TCmp, m_Zero()))
439 SimplifyXorInst(Cond, Constant::getAllOnesValue(Cond->getType()),
446 /// ThreadBinOpOverPHI - In the case of a binary operation with an operand that
447 /// is a PHI instruction, try to simplify the binop by seeing whether evaluating
448 /// it on the incoming phi values yields the same result for every value. If so
449 /// returns the common value, otherwise returns null.
450 static Value *ThreadBinOpOverPHI(unsigned Opcode, Value *LHS, Value *RHS,
451 const Query &Q, unsigned MaxRecurse) {
452 // Recursion is always used, so bail out at once if we already hit the limit.
457 if (isa<PHINode>(LHS)) {
458 PI = cast<PHINode>(LHS);
459 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
460 if (!ValueDominatesPHI(RHS, PI, Q.DT))
463 assert(isa<PHINode>(RHS) && "No PHI instruction operand!");
464 PI = cast<PHINode>(RHS);
465 // Bail out if LHS and the phi may be mutually interdependent due to a loop.
466 if (!ValueDominatesPHI(LHS, PI, Q.DT))
470 // Evaluate the BinOp on the incoming phi values.
471 Value *CommonValue = nullptr;
472 for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
473 Value *Incoming = PI->getIncomingValue(i);
474 // If the incoming value is the phi node itself, it can safely be skipped.
475 if (Incoming == PI) continue;
476 Value *V = PI == LHS ?
477 SimplifyBinOp(Opcode, Incoming, RHS, Q, MaxRecurse) :
478 SimplifyBinOp(Opcode, LHS, Incoming, Q, MaxRecurse);
479 // If the operation failed to simplify, or simplified to a different value
480 // to previously, then give up.
481 if (!V || (CommonValue && V != CommonValue))
489 /// ThreadCmpOverPHI - In the case of a comparison with a PHI instruction, try
490 /// try to simplify the comparison by seeing whether comparing with all of the
491 /// incoming phi values yields the same result every time. If so returns the
492 /// common result, otherwise returns null.
493 static Value *ThreadCmpOverPHI(CmpInst::Predicate Pred, Value *LHS, Value *RHS,
494 const Query &Q, unsigned MaxRecurse) {
495 // Recursion is always used, so bail out at once if we already hit the limit.
499 // Make sure the phi is on the LHS.
500 if (!isa<PHINode>(LHS)) {
502 Pred = CmpInst::getSwappedPredicate(Pred);
504 assert(isa<PHINode>(LHS) && "Not comparing with a phi instruction!");
505 PHINode *PI = cast<PHINode>(LHS);
507 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
508 if (!ValueDominatesPHI(RHS, PI, Q.DT))
511 // Evaluate the BinOp on the incoming phi values.
512 Value *CommonValue = nullptr;
513 for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
514 Value *Incoming = PI->getIncomingValue(i);
515 // If the incoming value is the phi node itself, it can safely be skipped.
516 if (Incoming == PI) continue;
517 Value *V = SimplifyCmpInst(Pred, Incoming, RHS, Q, MaxRecurse);
518 // If the operation failed to simplify, or simplified to a different value
519 // to previously, then give up.
520 if (!V || (CommonValue && V != CommonValue))
528 /// SimplifyAddInst - Given operands for an Add, see if we can
529 /// fold the result. If not, this returns null.
530 static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
531 const Query &Q, unsigned MaxRecurse) {
532 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
533 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
534 Constant *Ops[] = { CLHS, CRHS };
535 return ConstantFoldInstOperands(Instruction::Add, CLHS->getType(), Ops,
539 // Canonicalize the constant to the RHS.
543 // X + undef -> undef
544 if (match(Op1, m_Undef()))
548 if (match(Op1, m_Zero()))
555 if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) ||
556 match(Op0, m_Sub(m_Value(Y), m_Specific(Op1))))
559 // X + ~X -> -1 since ~X = -X-1
560 if (match(Op0, m_Not(m_Specific(Op1))) ||
561 match(Op1, m_Not(m_Specific(Op0))))
562 return Constant::getAllOnesValue(Op0->getType());
565 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
566 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
569 // Try some generic simplifications for associative operations.
570 if (Value *V = SimplifyAssociativeBinOp(Instruction::Add, Op0, Op1, Q,
574 // Threading Add over selects and phi nodes is pointless, so don't bother.
575 // Threading over the select in "A + select(cond, B, C)" means evaluating
576 // "A+B" and "A+C" and seeing if they are equal; but they are equal if and
577 // only if B and C are equal. If B and C are equal then (since we assume
578 // that operands have already been simplified) "select(cond, B, C)" should
579 // have been simplified to the common value of B and C already. Analysing
580 // "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly
581 // for threading over phi nodes.
586 Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
587 const DataLayout *DL, const TargetLibraryInfo *TLI,
588 const DominatorTree *DT, AssumptionCache *AC,
589 const Instruction *CxtI) {
590 return ::SimplifyAddInst(Op0, Op1, isNSW, isNUW, Query(DL, TLI, DT, AC, CxtI),
594 /// \brief Compute the base pointer and cumulative constant offsets for V.
596 /// This strips all constant offsets off of V, leaving it the base pointer, and
597 /// accumulates the total constant offset applied in the returned constant. It
598 /// returns 0 if V is not a pointer, and returns the constant '0' if there are
599 /// no constant offsets applied.
601 /// This is very similar to GetPointerBaseWithConstantOffset except it doesn't
602 /// follow non-inbounds geps. This allows it to remain usable for icmp ult/etc.
604 static Constant *stripAndComputeConstantOffsets(const DataLayout *DL,
606 bool AllowNonInbounds = false) {
607 assert(V->getType()->getScalarType()->isPointerTy());
609 // Without DataLayout, just be conservative for now. Theoretically, more could
610 // be done in this case.
612 return ConstantInt::get(IntegerType::get(V->getContext(), 64), 0);
614 Type *IntPtrTy = DL->getIntPtrType(V->getType())->getScalarType();
615 APInt Offset = APInt::getNullValue(IntPtrTy->getIntegerBitWidth());
617 // Even though we don't look through PHI nodes, we could be called on an
618 // instruction in an unreachable block, which may be on a cycle.
619 SmallPtrSet<Value *, 4> Visited;
622 if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
623 if ((!AllowNonInbounds && !GEP->isInBounds()) ||
624 !GEP->accumulateConstantOffset(*DL, Offset))
626 V = GEP->getPointerOperand();
627 } else if (Operator::getOpcode(V) == Instruction::BitCast) {
628 V = cast<Operator>(V)->getOperand(0);
629 } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
630 if (GA->mayBeOverridden())
632 V = GA->getAliasee();
636 assert(V->getType()->getScalarType()->isPointerTy() &&
637 "Unexpected operand type!");
638 } while (Visited.insert(V).second);
640 Constant *OffsetIntPtr = ConstantInt::get(IntPtrTy, Offset);
641 if (V->getType()->isVectorTy())
642 return ConstantVector::getSplat(V->getType()->getVectorNumElements(),
647 /// \brief Compute the constant difference between two pointer values.
648 /// If the difference is not a constant, returns zero.
649 static Constant *computePointerDifference(const DataLayout *DL,
650 Value *LHS, Value *RHS) {
651 Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
652 Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
654 // If LHS and RHS are not related via constant offsets to the same base
655 // value, there is nothing we can do here.
659 // Otherwise, the difference of LHS - RHS can be computed as:
661 // = (LHSOffset + Base) - (RHSOffset + Base)
662 // = LHSOffset - RHSOffset
663 return ConstantExpr::getSub(LHSOffset, RHSOffset);
666 /// SimplifySubInst - Given operands for a Sub, see if we can
667 /// fold the result. If not, this returns null.
668 static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
669 const Query &Q, unsigned MaxRecurse) {
670 if (Constant *CLHS = dyn_cast<Constant>(Op0))
671 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
672 Constant *Ops[] = { CLHS, CRHS };
673 return ConstantFoldInstOperands(Instruction::Sub, CLHS->getType(),
677 // X - undef -> undef
678 // undef - X -> undef
679 if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
680 return UndefValue::get(Op0->getType());
683 if (match(Op1, m_Zero()))
688 return Constant::getNullValue(Op0->getType());
690 // 0 - X -> 0 if the sub is NUW.
691 if (isNUW && match(Op0, m_Zero()))
694 // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
695 // For example, (X + Y) - Y -> X; (Y + X) - Y -> X
696 Value *X = nullptr, *Y = nullptr, *Z = Op1;
697 if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z
698 // See if "V === Y - Z" simplifies.
699 if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, Q, MaxRecurse-1))
700 // It does! Now see if "X + V" simplifies.
701 if (Value *W = SimplifyBinOp(Instruction::Add, X, V, Q, MaxRecurse-1)) {
702 // It does, we successfully reassociated!
706 // See if "V === X - Z" simplifies.
707 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
708 // It does! Now see if "Y + V" simplifies.
709 if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, Q, MaxRecurse-1)) {
710 // It does, we successfully reassociated!
716 // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
717 // For example, X - (X + 1) -> -1
719 if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z)
720 // See if "V === X - Y" simplifies.
721 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
722 // It does! Now see if "V - Z" simplifies.
723 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, Q, MaxRecurse-1)) {
724 // It does, we successfully reassociated!
728 // See if "V === X - Z" simplifies.
729 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
730 // It does! Now see if "V - Y" simplifies.
731 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, Q, MaxRecurse-1)) {
732 // It does, we successfully reassociated!
738 // Z - (X - Y) -> (Z - X) + Y if everything simplifies.
739 // For example, X - (X - Y) -> Y.
741 if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y)
742 // See if "V === Z - X" simplifies.
743 if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, Q, MaxRecurse-1))
744 // It does! Now see if "V + Y" simplifies.
745 if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, Q, MaxRecurse-1)) {
746 // It does, we successfully reassociated!
751 // trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies.
752 if (MaxRecurse && match(Op0, m_Trunc(m_Value(X))) &&
753 match(Op1, m_Trunc(m_Value(Y))))
754 if (X->getType() == Y->getType())
755 // See if "V === X - Y" simplifies.
756 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
757 // It does! Now see if "trunc V" simplifies.
758 if (Value *W = SimplifyTruncInst(V, Op0->getType(), Q, MaxRecurse-1))
759 // It does, return the simplified "trunc V".
762 // Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...).
763 if (match(Op0, m_PtrToInt(m_Value(X))) &&
764 match(Op1, m_PtrToInt(m_Value(Y))))
765 if (Constant *Result = computePointerDifference(Q.DL, X, Y))
766 return ConstantExpr::getIntegerCast(Result, Op0->getType(), true);
769 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
770 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
773 // Threading Sub over selects and phi nodes is pointless, so don't bother.
774 // Threading over the select in "A - select(cond, B, C)" means evaluating
775 // "A-B" and "A-C" and seeing if they are equal; but they are equal if and
776 // only if B and C are equal. If B and C are equal then (since we assume
777 // that operands have already been simplified) "select(cond, B, C)" should
778 // have been simplified to the common value of B and C already. Analysing
779 // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly
780 // for threading over phi nodes.
785 Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
786 const DataLayout *DL, const TargetLibraryInfo *TLI,
787 const DominatorTree *DT, AssumptionCache *AC,
788 const Instruction *CxtI) {
789 return ::SimplifySubInst(Op0, Op1, isNSW, isNUW, Query(DL, TLI, DT, AC, CxtI),
793 /// Given operands for an FAdd, see if we can fold the result. If not, this
795 static Value *SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
796 const Query &Q, unsigned MaxRecurse) {
797 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
798 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
799 Constant *Ops[] = { CLHS, CRHS };
800 return ConstantFoldInstOperands(Instruction::FAdd, CLHS->getType(),
804 // Canonicalize the constant to the RHS.
809 if (match(Op1, m_NegZero()))
812 // fadd X, 0 ==> X, when we know X is not -0
813 if (match(Op1, m_Zero()) &&
814 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
817 // fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
818 // where nnan and ninf have to occur at least once somewhere in this
820 Value *SubOp = nullptr;
821 if (match(Op1, m_FSub(m_AnyZero(), m_Specific(Op0))))
823 else if (match(Op0, m_FSub(m_AnyZero(), m_Specific(Op1))))
826 Instruction *FSub = cast<Instruction>(SubOp);
827 if ((FMF.noNaNs() || FSub->hasNoNaNs()) &&
828 (FMF.noInfs() || FSub->hasNoInfs()))
829 return Constant::getNullValue(Op0->getType());
835 /// Given operands for an FSub, see if we can fold the result. If not, this
837 static Value *SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
838 const Query &Q, unsigned MaxRecurse) {
839 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
840 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
841 Constant *Ops[] = { CLHS, CRHS };
842 return ConstantFoldInstOperands(Instruction::FSub, CLHS->getType(),
848 if (match(Op1, m_Zero()))
851 // fsub X, -0 ==> X, when we know X is not -0
852 if (match(Op1, m_NegZero()) &&
853 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
856 // fsub 0, (fsub -0.0, X) ==> X
858 if (match(Op0, m_AnyZero())) {
859 if (match(Op1, m_FSub(m_NegZero(), m_Value(X))))
861 if (FMF.noSignedZeros() && match(Op1, m_FSub(m_AnyZero(), m_Value(X))))
865 // fsub nnan ninf x, x ==> 0.0
866 if (FMF.noNaNs() && FMF.noInfs() && Op0 == Op1)
867 return Constant::getNullValue(Op0->getType());
872 /// Given the operands for an FMul, see if we can fold the result
873 static Value *SimplifyFMulInst(Value *Op0, Value *Op1,
876 unsigned MaxRecurse) {
877 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
878 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
879 Constant *Ops[] = { CLHS, CRHS };
880 return ConstantFoldInstOperands(Instruction::FMul, CLHS->getType(),
884 // Canonicalize the constant to the RHS.
889 if (match(Op1, m_FPOne()))
892 // fmul nnan nsz X, 0 ==> 0
893 if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZero()))
899 /// SimplifyMulInst - Given operands for a Mul, see if we can
900 /// fold the result. If not, this returns null.
901 static Value *SimplifyMulInst(Value *Op0, Value *Op1, const Query &Q,
902 unsigned MaxRecurse) {
903 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
904 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
905 Constant *Ops[] = { CLHS, CRHS };
906 return ConstantFoldInstOperands(Instruction::Mul, CLHS->getType(),
910 // Canonicalize the constant to the RHS.
915 if (match(Op1, m_Undef()))
916 return Constant::getNullValue(Op0->getType());
919 if (match(Op1, m_Zero()))
923 if (match(Op1, m_One()))
926 // (X / Y) * Y -> X if the division is exact.
928 if (match(Op0, m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y
929 match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0))))) // Y * (X / Y)
933 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
934 if (Value *V = SimplifyAndInst(Op0, Op1, Q, MaxRecurse-1))
937 // Try some generic simplifications for associative operations.
938 if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, Q,
942 // Mul distributes over Add. Try some generic simplifications based on this.
943 if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add,
947 // If the operation is with the result of a select instruction, check whether
948 // operating on either branch of the select always yields the same value.
949 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
950 if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, Q,
954 // If the operation is with the result of a phi instruction, check whether
955 // operating on all incoming values of the phi always yields the same value.
956 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
957 if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, Q,
964 Value *llvm::SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
965 const DataLayout *DL,
966 const TargetLibraryInfo *TLI,
967 const DominatorTree *DT, AssumptionCache *AC,
968 const Instruction *CxtI) {
969 return ::SimplifyFAddInst(Op0, Op1, FMF, Query(DL, TLI, DT, AC, CxtI),
973 Value *llvm::SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
974 const DataLayout *DL,
975 const TargetLibraryInfo *TLI,
976 const DominatorTree *DT, AssumptionCache *AC,
977 const Instruction *CxtI) {
978 return ::SimplifyFSubInst(Op0, Op1, FMF, Query(DL, TLI, DT, AC, CxtI),
982 Value *llvm::SimplifyFMulInst(Value *Op0, Value *Op1, FastMathFlags FMF,
983 const DataLayout *DL,
984 const TargetLibraryInfo *TLI,
985 const DominatorTree *DT, AssumptionCache *AC,
986 const Instruction *CxtI) {
987 return ::SimplifyFMulInst(Op0, Op1, FMF, Query(DL, TLI, DT, AC, CxtI),
991 Value *llvm::SimplifyMulInst(Value *Op0, Value *Op1, const DataLayout *DL,
992 const TargetLibraryInfo *TLI,
993 const DominatorTree *DT, AssumptionCache *AC,
994 const Instruction *CxtI) {
995 return ::SimplifyMulInst(Op0, Op1, Query(DL, TLI, DT, AC, CxtI),
999 /// SimplifyDiv - Given operands for an SDiv or UDiv, see if we can
1000 /// fold the result. If not, this returns null.
1001 static Value *SimplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
1002 const Query &Q, unsigned MaxRecurse) {
1003 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1004 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1005 Constant *Ops[] = { C0, C1 };
1006 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.DL, Q.TLI);
1010 bool isSigned = Opcode == Instruction::SDiv;
1012 // X / undef -> undef
1013 if (match(Op1, m_Undef()))
1016 // X / 0 -> undef, we don't need to preserve faults!
1017 if (match(Op1, m_Zero()))
1018 return UndefValue::get(Op1->getType());
1021 if (match(Op0, m_Undef()))
1022 return Constant::getNullValue(Op0->getType());
1024 // 0 / X -> 0, we don't need to preserve faults!
1025 if (match(Op0, m_Zero()))
1029 if (match(Op1, m_One()))
1032 if (Op0->getType()->isIntegerTy(1))
1033 // It can't be division by zero, hence it must be division by one.
1038 return ConstantInt::get(Op0->getType(), 1);
1040 // (X * Y) / Y -> X if the multiplication does not overflow.
1041 Value *X = nullptr, *Y = nullptr;
1042 if (match(Op0, m_Mul(m_Value(X), m_Value(Y))) && (X == Op1 || Y == Op1)) {
1043 if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1
1044 OverflowingBinaryOperator *Mul = cast<OverflowingBinaryOperator>(Op0);
1045 // If the Mul knows it does not overflow, then we are good to go.
1046 if ((isSigned && Mul->hasNoSignedWrap()) ||
1047 (!isSigned && Mul->hasNoUnsignedWrap()))
1049 // If X has the form X = A / Y then X * Y cannot overflow.
1050 if (BinaryOperator *Div = dyn_cast<BinaryOperator>(X))
1051 if (Div->getOpcode() == Opcode && Div->getOperand(1) == Y)
1055 // (X rem Y) / Y -> 0
1056 if ((isSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1057 (!isSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1058 return Constant::getNullValue(Op0->getType());
1060 // (X /u C1) /u C2 -> 0 if C1 * C2 overflow
1061 ConstantInt *C1, *C2;
1062 if (!isSigned && match(Op0, m_UDiv(m_Value(X), m_ConstantInt(C1))) &&
1063 match(Op1, m_ConstantInt(C2))) {
1065 C1->getValue().umul_ov(C2->getValue(), Overflow);
1067 return Constant::getNullValue(Op0->getType());
1070 // If the operation is with the result of a select instruction, check whether
1071 // operating on either branch of the select always yields the same value.
1072 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1073 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1076 // If the operation is with the result of a phi instruction, check whether
1077 // operating on all incoming values of the phi always yields the same value.
1078 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1079 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1085 /// SimplifySDivInst - Given operands for an SDiv, see if we can
1086 /// fold the result. If not, this returns null.
1087 static Value *SimplifySDivInst(Value *Op0, Value *Op1, const Query &Q,
1088 unsigned MaxRecurse) {
1089 if (Value *V = SimplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse))
1095 Value *llvm::SimplifySDivInst(Value *Op0, Value *Op1, const DataLayout *DL,
1096 const TargetLibraryInfo *TLI,
1097 const DominatorTree *DT, AssumptionCache *AC,
1098 const Instruction *CxtI) {
1099 return ::SimplifySDivInst(Op0, Op1, Query(DL, TLI, DT, AC, CxtI),
1103 /// SimplifyUDivInst - Given operands for a UDiv, see if we can
1104 /// fold the result. If not, this returns null.
1105 static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const Query &Q,
1106 unsigned MaxRecurse) {
1107 if (Value *V = SimplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse))
1113 Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const DataLayout *DL,
1114 const TargetLibraryInfo *TLI,
1115 const DominatorTree *DT, AssumptionCache *AC,
1116 const Instruction *CxtI) {
1117 return ::SimplifyUDivInst(Op0, Op1, Query(DL, TLI, DT, AC, CxtI),
1121 static Value *SimplifyFDivInst(Value *Op0, Value *Op1, const Query &Q,
1123 // undef / X -> undef (the undef could be a snan).
1124 if (match(Op0, m_Undef()))
1127 // X / undef -> undef
1128 if (match(Op1, m_Undef()))
1134 Value *llvm::SimplifyFDivInst(Value *Op0, Value *Op1, const DataLayout *DL,
1135 const TargetLibraryInfo *TLI,
1136 const DominatorTree *DT, AssumptionCache *AC,
1137 const Instruction *CxtI) {
1138 return ::SimplifyFDivInst(Op0, Op1, Query(DL, TLI, DT, AC, CxtI),
1142 /// SimplifyRem - Given operands for an SRem or URem, see if we can
1143 /// fold the result. If not, this returns null.
1144 static Value *SimplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
1145 const Query &Q, unsigned MaxRecurse) {
1146 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1147 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1148 Constant *Ops[] = { C0, C1 };
1149 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.DL, Q.TLI);
1153 // X % undef -> undef
1154 if (match(Op1, m_Undef()))
1158 if (match(Op0, m_Undef()))
1159 return Constant::getNullValue(Op0->getType());
1161 // 0 % X -> 0, we don't need to preserve faults!
1162 if (match(Op0, m_Zero()))
1165 // X % 0 -> undef, we don't need to preserve faults!
1166 if (match(Op1, m_Zero()))
1167 return UndefValue::get(Op0->getType());
1170 if (match(Op1, m_One()))
1171 return Constant::getNullValue(Op0->getType());
1173 if (Op0->getType()->isIntegerTy(1))
1174 // It can't be remainder by zero, hence it must be remainder by one.
1175 return Constant::getNullValue(Op0->getType());
1179 return Constant::getNullValue(Op0->getType());
1181 // (X % Y) % Y -> X % Y
1182 if ((Opcode == Instruction::SRem &&
1183 match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1184 (Opcode == Instruction::URem &&
1185 match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1188 // If the operation is with the result of a select instruction, check whether
1189 // operating on either branch of the select always yields the same value.
1190 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1191 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1194 // If the operation is with the result of a phi instruction, check whether
1195 // operating on all incoming values of the phi always yields the same value.
1196 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1197 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1203 /// SimplifySRemInst - Given operands for an SRem, see if we can
1204 /// fold the result. If not, this returns null.
1205 static Value *SimplifySRemInst(Value *Op0, Value *Op1, const Query &Q,
1206 unsigned MaxRecurse) {
1207 if (Value *V = SimplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse))
1213 Value *llvm::SimplifySRemInst(Value *Op0, Value *Op1, const DataLayout *DL,
1214 const TargetLibraryInfo *TLI,
1215 const DominatorTree *DT, AssumptionCache *AC,
1216 const Instruction *CxtI) {
1217 return ::SimplifySRemInst(Op0, Op1, Query(DL, TLI, DT, AC, CxtI),
1221 /// SimplifyURemInst - Given operands for a URem, see if we can
1222 /// fold the result. If not, this returns null.
1223 static Value *SimplifyURemInst(Value *Op0, Value *Op1, const Query &Q,
1224 unsigned MaxRecurse) {
1225 if (Value *V = SimplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse))
1231 Value *llvm::SimplifyURemInst(Value *Op0, Value *Op1, const DataLayout *DL,
1232 const TargetLibraryInfo *TLI,
1233 const DominatorTree *DT, AssumptionCache *AC,
1234 const Instruction *CxtI) {
1235 return ::SimplifyURemInst(Op0, Op1, Query(DL, TLI, DT, AC, CxtI),
1239 static Value *SimplifyFRemInst(Value *Op0, Value *Op1, const Query &,
1241 // undef % X -> undef (the undef could be a snan).
1242 if (match(Op0, m_Undef()))
1245 // X % undef -> undef
1246 if (match(Op1, m_Undef()))
1252 Value *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, const DataLayout *DL,
1253 const TargetLibraryInfo *TLI,
1254 const DominatorTree *DT, AssumptionCache *AC,
1255 const Instruction *CxtI) {
1256 return ::SimplifyFRemInst(Op0, Op1, Query(DL, TLI, DT, AC, CxtI),
1260 /// isUndefShift - Returns true if a shift by \c Amount always yields undef.
1261 static bool isUndefShift(Value *Amount) {
1262 Constant *C = dyn_cast<Constant>(Amount);
1266 // X shift by undef -> undef because it may shift by the bitwidth.
1267 if (isa<UndefValue>(C))
1270 // Shifting by the bitwidth or more is undefined.
1271 if (ConstantInt *CI = dyn_cast<ConstantInt>(C))
1272 if (CI->getValue().getLimitedValue() >=
1273 CI->getType()->getScalarSizeInBits())
1276 // If all lanes of a vector shift are undefined the whole shift is.
1277 if (isa<ConstantVector>(C) || isa<ConstantDataVector>(C)) {
1278 for (unsigned I = 0, E = C->getType()->getVectorNumElements(); I != E; ++I)
1279 if (!isUndefShift(C->getAggregateElement(I)))
1287 /// SimplifyShift - Given operands for an Shl, LShr or AShr, see if we can
1288 /// fold the result. If not, this returns null.
1289 static Value *SimplifyShift(unsigned Opcode, Value *Op0, Value *Op1,
1290 const Query &Q, unsigned MaxRecurse) {
1291 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1292 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1293 Constant *Ops[] = { C0, C1 };
1294 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.DL, Q.TLI);
1298 // 0 shift by X -> 0
1299 if (match(Op0, m_Zero()))
1302 // X shift by 0 -> X
1303 if (match(Op1, m_Zero()))
1306 // Fold undefined shifts.
1307 if (isUndefShift(Op1))
1308 return UndefValue::get(Op0->getType());
1310 // If the operation is with the result of a select instruction, check whether
1311 // operating on either branch of the select always yields the same value.
1312 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1313 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1316 // If the operation is with the result of a phi instruction, check whether
1317 // operating on all incoming values of the phi always yields the same value.
1318 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1319 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1325 /// \brief Given operands for an Shl, LShr or AShr, see if we can
1326 /// fold the result. If not, this returns null.
1327 static Value *SimplifyRightShift(unsigned Opcode, Value *Op0, Value *Op1,
1328 bool isExact, const Query &Q,
1329 unsigned MaxRecurse) {
1330 if (Value *V = SimplifyShift(Opcode, Op0, Op1, Q, MaxRecurse))
1335 return Constant::getNullValue(Op0->getType());
1338 // undef >> X -> undef (if it's exact)
1339 if (match(Op0, m_Undef()))
1340 return isExact ? Op0 : Constant::getNullValue(Op0->getType());
1342 // The low bit cannot be shifted out of an exact shift if it is set.
1344 unsigned BitWidth = Op0->getType()->getScalarSizeInBits();
1345 APInt Op0KnownZero(BitWidth, 0);
1346 APInt Op0KnownOne(BitWidth, 0);
1347 computeKnownBits(Op0, Op0KnownZero, Op0KnownOne, Q.DL, /*Depth=*/0, Q.AC,
1356 /// SimplifyShlInst - Given operands for an Shl, see if we can
1357 /// fold the result. If not, this returns null.
1358 static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1359 const Query &Q, unsigned MaxRecurse) {
1360 if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse))
1364 // undef << X -> undef if (if it's NSW/NUW)
1365 if (match(Op0, m_Undef()))
1366 return isNSW || isNUW ? Op0 : Constant::getNullValue(Op0->getType());
1368 // (X >> A) << A -> X
1370 if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
1375 Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1376 const DataLayout *DL, const TargetLibraryInfo *TLI,
1377 const DominatorTree *DT, AssumptionCache *AC,
1378 const Instruction *CxtI) {
1379 return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Query(DL, TLI, DT, AC, CxtI),
1383 /// SimplifyLShrInst - Given operands for an LShr, see if we can
1384 /// fold the result. If not, this returns null.
1385 static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1386 const Query &Q, unsigned MaxRecurse) {
1387 if (Value *V = SimplifyRightShift(Instruction::LShr, Op0, Op1, isExact, Q,
1391 // (X << A) >> A -> X
1393 if (match(Op0, m_NUWShl(m_Value(X), m_Specific(Op1))))
1399 Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1400 const DataLayout *DL,
1401 const TargetLibraryInfo *TLI,
1402 const DominatorTree *DT, AssumptionCache *AC,
1403 const Instruction *CxtI) {
1404 return ::SimplifyLShrInst(Op0, Op1, isExact, Query(DL, TLI, DT, AC, CxtI),
1408 /// SimplifyAShrInst - Given operands for an AShr, see if we can
1409 /// fold the result. If not, this returns null.
1410 static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1411 const Query &Q, unsigned MaxRecurse) {
1412 if (Value *V = SimplifyRightShift(Instruction::AShr, Op0, Op1, isExact, Q,
1416 // all ones >>a X -> all ones
1417 if (match(Op0, m_AllOnes()))
1420 // (X << A) >> A -> X
1422 if (match(Op0, m_NSWShl(m_Value(X), m_Specific(Op1))))
1425 // Arithmetic shifting an all-sign-bit value is a no-op.
1426 unsigned NumSignBits = ComputeNumSignBits(Op0, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
1427 if (NumSignBits == Op0->getType()->getScalarSizeInBits())
1433 Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1434 const DataLayout *DL,
1435 const TargetLibraryInfo *TLI,
1436 const DominatorTree *DT, AssumptionCache *AC,
1437 const Instruction *CxtI) {
1438 return ::SimplifyAShrInst(Op0, Op1, isExact, Query(DL, TLI, DT, AC, CxtI),
1442 static Value *simplifyUnsignedRangeCheck(ICmpInst *ZeroICmp,
1443 ICmpInst *UnsignedICmp, bool IsAnd) {
1446 ICmpInst::Predicate EqPred;
1447 if (!match(ZeroICmp, m_ICmp(EqPred, m_Value(Y), m_Zero())) ||
1448 !ICmpInst::isEquality(EqPred))
1451 ICmpInst::Predicate UnsignedPred;
1452 if (match(UnsignedICmp, m_ICmp(UnsignedPred, m_Value(X), m_Specific(Y))) &&
1453 ICmpInst::isUnsigned(UnsignedPred))
1455 else if (match(UnsignedICmp,
1456 m_ICmp(UnsignedPred, m_Value(Y), m_Specific(X))) &&
1457 ICmpInst::isUnsigned(UnsignedPred))
1458 UnsignedPred = ICmpInst::getSwappedPredicate(UnsignedPred);
1462 // X < Y && Y != 0 --> X < Y
1463 // X < Y || Y != 0 --> Y != 0
1464 if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_NE)
1465 return IsAnd ? UnsignedICmp : ZeroICmp;
1467 // X >= Y || Y != 0 --> true
1468 // X >= Y || Y == 0 --> X >= Y
1469 if (UnsignedPred == ICmpInst::ICMP_UGE && !IsAnd) {
1470 if (EqPred == ICmpInst::ICMP_NE)
1471 return getTrue(UnsignedICmp->getType());
1472 return UnsignedICmp;
1475 // X < Y && Y == 0 --> false
1476 if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_EQ &&
1478 return getFalse(UnsignedICmp->getType());
1483 // Simplify (and (icmp ...) (icmp ...)) to true when we can tell that the range
1484 // of possible values cannot be satisfied.
1485 static Value *SimplifyAndOfICmps(ICmpInst *Op0, ICmpInst *Op1) {
1486 ICmpInst::Predicate Pred0, Pred1;
1487 ConstantInt *CI1, *CI2;
1490 if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/true))
1493 if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_ConstantInt(CI1)),
1494 m_ConstantInt(CI2))))
1497 if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Specific(CI1))))
1500 Type *ITy = Op0->getType();
1502 auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1503 bool isNSW = AddInst->hasNoSignedWrap();
1504 bool isNUW = AddInst->hasNoUnsignedWrap();
1506 const APInt &CI1V = CI1->getValue();
1507 const APInt &CI2V = CI2->getValue();
1508 const APInt Delta = CI2V - CI1V;
1509 if (CI1V.isStrictlyPositive()) {
1511 if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_SGT)
1512 return getFalse(ITy);
1513 if (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1514 return getFalse(ITy);
1517 if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_SGT)
1518 return getFalse(ITy);
1519 if (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1520 return getFalse(ITy);
1523 if (CI1V.getBoolValue() && isNUW) {
1525 if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT)
1526 return getFalse(ITy);
1528 if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGT)
1529 return getFalse(ITy);
1535 /// SimplifyAndInst - Given operands for an And, see if we can
1536 /// fold the result. If not, this returns null.
1537 static Value *SimplifyAndInst(Value *Op0, Value *Op1, const Query &Q,
1538 unsigned MaxRecurse) {
1539 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1540 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1541 Constant *Ops[] = { CLHS, CRHS };
1542 return ConstantFoldInstOperands(Instruction::And, CLHS->getType(),
1546 // Canonicalize the constant to the RHS.
1547 std::swap(Op0, Op1);
1551 if (match(Op1, m_Undef()))
1552 return Constant::getNullValue(Op0->getType());
1559 if (match(Op1, m_Zero()))
1563 if (match(Op1, m_AllOnes()))
1566 // A & ~A = ~A & A = 0
1567 if (match(Op0, m_Not(m_Specific(Op1))) ||
1568 match(Op1, m_Not(m_Specific(Op0))))
1569 return Constant::getNullValue(Op0->getType());
1572 Value *A = nullptr, *B = nullptr;
1573 if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
1574 (A == Op1 || B == Op1))
1578 if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
1579 (A == Op0 || B == Op0))
1582 // A & (-A) = A if A is a power of two or zero.
1583 if (match(Op0, m_Neg(m_Specific(Op1))) ||
1584 match(Op1, m_Neg(m_Specific(Op0)))) {
1585 if (isKnownToBeAPowerOfTwo(Op0, /*OrZero*/ true, 0, Q.AC, Q.CxtI, Q.DT))
1587 if (isKnownToBeAPowerOfTwo(Op1, /*OrZero*/ true, 0, Q.AC, Q.CxtI, Q.DT))
1591 if (auto *ICILHS = dyn_cast<ICmpInst>(Op0)) {
1592 if (auto *ICIRHS = dyn_cast<ICmpInst>(Op1)) {
1593 if (Value *V = SimplifyAndOfICmps(ICILHS, ICIRHS))
1595 if (Value *V = SimplifyAndOfICmps(ICIRHS, ICILHS))
1600 // Try some generic simplifications for associative operations.
1601 if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
1605 // And distributes over Or. Try some generic simplifications based on this.
1606 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1610 // And distributes over Xor. Try some generic simplifications based on this.
1611 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
1615 // If the operation is with the result of a select instruction, check whether
1616 // operating on either branch of the select always yields the same value.
1617 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1618 if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
1622 // If the operation is with the result of a phi instruction, check whether
1623 // operating on all incoming values of the phi always yields the same value.
1624 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1625 if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
1632 Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const DataLayout *DL,
1633 const TargetLibraryInfo *TLI,
1634 const DominatorTree *DT, AssumptionCache *AC,
1635 const Instruction *CxtI) {
1636 return ::SimplifyAndInst(Op0, Op1, Query(DL, TLI, DT, AC, CxtI),
1640 // Simplify (or (icmp ...) (icmp ...)) to true when we can tell that the union
1641 // contains all possible values.
1642 static Value *SimplifyOrOfICmps(ICmpInst *Op0, ICmpInst *Op1) {
1643 ICmpInst::Predicate Pred0, Pred1;
1644 ConstantInt *CI1, *CI2;
1647 if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/false))
1650 if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_ConstantInt(CI1)),
1651 m_ConstantInt(CI2))))
1654 if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Specific(CI1))))
1657 Type *ITy = Op0->getType();
1659 auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1660 bool isNSW = AddInst->hasNoSignedWrap();
1661 bool isNUW = AddInst->hasNoUnsignedWrap();
1663 const APInt &CI1V = CI1->getValue();
1664 const APInt &CI2V = CI2->getValue();
1665 const APInt Delta = CI2V - CI1V;
1666 if (CI1V.isStrictlyPositive()) {
1668 if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_SLE)
1669 return getTrue(ITy);
1670 if (Pred0 == ICmpInst::ICMP_SGE && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1671 return getTrue(ITy);
1674 if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_SLE)
1675 return getTrue(ITy);
1676 if (Pred0 == ICmpInst::ICMP_SGT && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1677 return getTrue(ITy);
1680 if (CI1V.getBoolValue() && isNUW) {
1682 if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_ULE)
1683 return getTrue(ITy);
1685 if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_ULE)
1686 return getTrue(ITy);
1692 /// SimplifyOrInst - Given operands for an Or, see if we can
1693 /// fold the result. If not, this returns null.
1694 static Value *SimplifyOrInst(Value *Op0, Value *Op1, const Query &Q,
1695 unsigned MaxRecurse) {
1696 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1697 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1698 Constant *Ops[] = { CLHS, CRHS };
1699 return ConstantFoldInstOperands(Instruction::Or, CLHS->getType(),
1703 // Canonicalize the constant to the RHS.
1704 std::swap(Op0, Op1);
1708 if (match(Op1, m_Undef()))
1709 return Constant::getAllOnesValue(Op0->getType());
1716 if (match(Op1, m_Zero()))
1720 if (match(Op1, m_AllOnes()))
1723 // A | ~A = ~A | A = -1
1724 if (match(Op0, m_Not(m_Specific(Op1))) ||
1725 match(Op1, m_Not(m_Specific(Op0))))
1726 return Constant::getAllOnesValue(Op0->getType());
1729 Value *A = nullptr, *B = nullptr;
1730 if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
1731 (A == Op1 || B == Op1))
1735 if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
1736 (A == Op0 || B == Op0))
1739 // ~(A & ?) | A = -1
1740 if (match(Op0, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1741 (A == Op1 || B == Op1))
1742 return Constant::getAllOnesValue(Op1->getType());
1744 // A | ~(A & ?) = -1
1745 if (match(Op1, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1746 (A == Op0 || B == Op0))
1747 return Constant::getAllOnesValue(Op0->getType());
1749 if (auto *ICILHS = dyn_cast<ICmpInst>(Op0)) {
1750 if (auto *ICIRHS = dyn_cast<ICmpInst>(Op1)) {
1751 if (Value *V = SimplifyOrOfICmps(ICILHS, ICIRHS))
1753 if (Value *V = SimplifyOrOfICmps(ICIRHS, ICILHS))
1758 // Try some generic simplifications for associative operations.
1759 if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
1763 // Or distributes over And. Try some generic simplifications based on this.
1764 if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
1768 // If the operation is with the result of a select instruction, check whether
1769 // operating on either branch of the select always yields the same value.
1770 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1771 if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
1776 Value *C = nullptr, *D = nullptr;
1777 if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
1778 match(Op1, m_And(m_Value(B), m_Value(D)))) {
1779 ConstantInt *C1 = dyn_cast<ConstantInt>(C);
1780 ConstantInt *C2 = dyn_cast<ConstantInt>(D);
1781 if (C1 && C2 && (C1->getValue() == ~C2->getValue())) {
1782 // (A & C1)|(B & C2)
1783 // If we have: ((V + N) & C1) | (V & C2)
1784 // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
1785 // replace with V+N.
1787 if ((C2->getValue() & (C2->getValue() + 1)) == 0 && // C2 == 0+1+
1788 match(A, m_Add(m_Value(V1), m_Value(V2)))) {
1789 // Add commutes, try both ways.
1791 MaskedValueIsZero(V2, C2->getValue(), Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
1794 MaskedValueIsZero(V1, C2->getValue(), Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
1797 // Or commutes, try both ways.
1798 if ((C1->getValue() & (C1->getValue() + 1)) == 0 &&
1799 match(B, m_Add(m_Value(V1), m_Value(V2)))) {
1800 // Add commutes, try both ways.
1802 MaskedValueIsZero(V2, C1->getValue(), Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
1805 MaskedValueIsZero(V1, C1->getValue(), Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
1811 // If the operation is with the result of a phi instruction, check whether
1812 // operating on all incoming values of the phi always yields the same value.
1813 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1814 if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
1820 Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const DataLayout *DL,
1821 const TargetLibraryInfo *TLI,
1822 const DominatorTree *DT, AssumptionCache *AC,
1823 const Instruction *CxtI) {
1824 return ::SimplifyOrInst(Op0, Op1, Query(DL, TLI, DT, AC, CxtI),
1828 /// SimplifyXorInst - Given operands for a Xor, see if we can
1829 /// fold the result. If not, this returns null.
1830 static Value *SimplifyXorInst(Value *Op0, Value *Op1, const Query &Q,
1831 unsigned MaxRecurse) {
1832 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1833 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1834 Constant *Ops[] = { CLHS, CRHS };
1835 return ConstantFoldInstOperands(Instruction::Xor, CLHS->getType(),
1839 // Canonicalize the constant to the RHS.
1840 std::swap(Op0, Op1);
1843 // A ^ undef -> undef
1844 if (match(Op1, m_Undef()))
1848 if (match(Op1, m_Zero()))
1853 return Constant::getNullValue(Op0->getType());
1855 // A ^ ~A = ~A ^ A = -1
1856 if (match(Op0, m_Not(m_Specific(Op1))) ||
1857 match(Op1, m_Not(m_Specific(Op0))))
1858 return Constant::getAllOnesValue(Op0->getType());
1860 // Try some generic simplifications for associative operations.
1861 if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
1865 // Threading Xor over selects and phi nodes is pointless, so don't bother.
1866 // Threading over the select in "A ^ select(cond, B, C)" means evaluating
1867 // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
1868 // only if B and C are equal. If B and C are equal then (since we assume
1869 // that operands have already been simplified) "select(cond, B, C)" should
1870 // have been simplified to the common value of B and C already. Analysing
1871 // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
1872 // for threading over phi nodes.
1877 Value *llvm::SimplifyXorInst(Value *Op0, Value *Op1, const DataLayout *DL,
1878 const TargetLibraryInfo *TLI,
1879 const DominatorTree *DT, AssumptionCache *AC,
1880 const Instruction *CxtI) {
1881 return ::SimplifyXorInst(Op0, Op1, Query(DL, TLI, DT, AC, CxtI),
1885 static Type *GetCompareTy(Value *Op) {
1886 return CmpInst::makeCmpResultType(Op->getType());
1889 /// ExtractEquivalentCondition - Rummage around inside V looking for something
1890 /// equivalent to the comparison "LHS Pred RHS". Return such a value if found,
1891 /// otherwise return null. Helper function for analyzing max/min idioms.
1892 static Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred,
1893 Value *LHS, Value *RHS) {
1894 SelectInst *SI = dyn_cast<SelectInst>(V);
1897 CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
1900 Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
1901 if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
1903 if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
1904 LHS == CmpRHS && RHS == CmpLHS)
1909 // A significant optimization not implemented here is assuming that alloca
1910 // addresses are not equal to incoming argument values. They don't *alias*,
1911 // as we say, but that doesn't mean they aren't equal, so we take a
1912 // conservative approach.
1914 // This is inspired in part by C++11 5.10p1:
1915 // "Two pointers of the same type compare equal if and only if they are both
1916 // null, both point to the same function, or both represent the same
1919 // This is pretty permissive.
1921 // It's also partly due to C11 6.5.9p6:
1922 // "Two pointers compare equal if and only if both are null pointers, both are
1923 // pointers to the same object (including a pointer to an object and a
1924 // subobject at its beginning) or function, both are pointers to one past the
1925 // last element of the same array object, or one is a pointer to one past the
1926 // end of one array object and the other is a pointer to the start of a
1927 // different array object that happens to immediately follow the first array
1928 // object in the address space.)
1930 // C11's version is more restrictive, however there's no reason why an argument
1931 // couldn't be a one-past-the-end value for a stack object in the caller and be
1932 // equal to the beginning of a stack object in the callee.
1934 // If the C and C++ standards are ever made sufficiently restrictive in this
1935 // area, it may be possible to update LLVM's semantics accordingly and reinstate
1936 // this optimization.
1937 static Constant *computePointerICmp(const DataLayout *DL,
1938 const TargetLibraryInfo *TLI,
1939 CmpInst::Predicate Pred,
1940 Value *LHS, Value *RHS) {
1941 // First, skip past any trivial no-ops.
1942 LHS = LHS->stripPointerCasts();
1943 RHS = RHS->stripPointerCasts();
1945 // A non-null pointer is not equal to a null pointer.
1946 if (llvm::isKnownNonNull(LHS, TLI) && isa<ConstantPointerNull>(RHS) &&
1947 (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE))
1948 return ConstantInt::get(GetCompareTy(LHS),
1949 !CmpInst::isTrueWhenEqual(Pred));
1951 // We can only fold certain predicates on pointer comparisons.
1956 // Equality comaprisons are easy to fold.
1957 case CmpInst::ICMP_EQ:
1958 case CmpInst::ICMP_NE:
1961 // We can only handle unsigned relational comparisons because 'inbounds' on
1962 // a GEP only protects against unsigned wrapping.
1963 case CmpInst::ICMP_UGT:
1964 case CmpInst::ICMP_UGE:
1965 case CmpInst::ICMP_ULT:
1966 case CmpInst::ICMP_ULE:
1967 // However, we have to switch them to their signed variants to handle
1968 // negative indices from the base pointer.
1969 Pred = ICmpInst::getSignedPredicate(Pred);
1973 // Strip off any constant offsets so that we can reason about them.
1974 // It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets
1975 // here and compare base addresses like AliasAnalysis does, however there are
1976 // numerous hazards. AliasAnalysis and its utilities rely on special rules
1977 // governing loads and stores which don't apply to icmps. Also, AliasAnalysis
1978 // doesn't need to guarantee pointer inequality when it says NoAlias.
1979 Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
1980 Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
1982 // If LHS and RHS are related via constant offsets to the same base
1983 // value, we can replace it with an icmp which just compares the offsets.
1985 return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset);
1987 // Various optimizations for (in)equality comparisons.
1988 if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE) {
1989 // Different non-empty allocations that exist at the same time have
1990 // different addresses (if the program can tell). Global variables always
1991 // exist, so they always exist during the lifetime of each other and all
1992 // allocas. Two different allocas usually have different addresses...
1994 // However, if there's an @llvm.stackrestore dynamically in between two
1995 // allocas, they may have the same address. It's tempting to reduce the
1996 // scope of the problem by only looking at *static* allocas here. That would
1997 // cover the majority of allocas while significantly reducing the likelihood
1998 // of having an @llvm.stackrestore pop up in the middle. However, it's not
1999 // actually impossible for an @llvm.stackrestore to pop up in the middle of
2000 // an entry block. Also, if we have a block that's not attached to a
2001 // function, we can't tell if it's "static" under the current definition.
2002 // Theoretically, this problem could be fixed by creating a new kind of
2003 // instruction kind specifically for static allocas. Such a new instruction
2004 // could be required to be at the top of the entry block, thus preventing it
2005 // from being subject to a @llvm.stackrestore. Instcombine could even
2006 // convert regular allocas into these special allocas. It'd be nifty.
2007 // However, until then, this problem remains open.
2009 // So, we'll assume that two non-empty allocas have different addresses
2012 // With all that, if the offsets are within the bounds of their allocations
2013 // (and not one-past-the-end! so we can't use inbounds!), and their
2014 // allocations aren't the same, the pointers are not equal.
2016 // Note that it's not necessary to check for LHS being a global variable
2017 // address, due to canonicalization and constant folding.
2018 if (isa<AllocaInst>(LHS) &&
2019 (isa<AllocaInst>(RHS) || isa<GlobalVariable>(RHS))) {
2020 ConstantInt *LHSOffsetCI = dyn_cast<ConstantInt>(LHSOffset);
2021 ConstantInt *RHSOffsetCI = dyn_cast<ConstantInt>(RHSOffset);
2022 uint64_t LHSSize, RHSSize;
2023 if (LHSOffsetCI && RHSOffsetCI &&
2024 getObjectSize(LHS, LHSSize, DL, TLI) &&
2025 getObjectSize(RHS, RHSSize, DL, TLI)) {
2026 const APInt &LHSOffsetValue = LHSOffsetCI->getValue();
2027 const APInt &RHSOffsetValue = RHSOffsetCI->getValue();
2028 if (!LHSOffsetValue.isNegative() &&
2029 !RHSOffsetValue.isNegative() &&
2030 LHSOffsetValue.ult(LHSSize) &&
2031 RHSOffsetValue.ult(RHSSize)) {
2032 return ConstantInt::get(GetCompareTy(LHS),
2033 !CmpInst::isTrueWhenEqual(Pred));
2037 // Repeat the above check but this time without depending on DataLayout
2038 // or being able to compute a precise size.
2039 if (!cast<PointerType>(LHS->getType())->isEmptyTy() &&
2040 !cast<PointerType>(RHS->getType())->isEmptyTy() &&
2041 LHSOffset->isNullValue() &&
2042 RHSOffset->isNullValue())
2043 return ConstantInt::get(GetCompareTy(LHS),
2044 !CmpInst::isTrueWhenEqual(Pred));
2047 // Even if an non-inbounds GEP occurs along the path we can still optimize
2048 // equality comparisons concerning the result. We avoid walking the whole
2049 // chain again by starting where the last calls to
2050 // stripAndComputeConstantOffsets left off and accumulate the offsets.
2051 Constant *LHSNoBound = stripAndComputeConstantOffsets(DL, LHS, true);
2052 Constant *RHSNoBound = stripAndComputeConstantOffsets(DL, RHS, true);
2054 return ConstantExpr::getICmp(Pred,
2055 ConstantExpr::getAdd(LHSOffset, LHSNoBound),
2056 ConstantExpr::getAdd(RHSOffset, RHSNoBound));
2058 // If one side of the equality comparison must come from a noalias call
2059 // (meaning a system memory allocation function), and the other side must
2060 // come from a pointer that cannot overlap with dynamically-allocated
2061 // memory within the lifetime of the current function (allocas, byval
2062 // arguments, globals), then determine the comparison result here.
2063 SmallVector<Value *, 8> LHSUObjs, RHSUObjs;
2064 GetUnderlyingObjects(LHS, LHSUObjs, DL);
2065 GetUnderlyingObjects(RHS, RHSUObjs, DL);
2067 // Is the set of underlying objects all noalias calls?
2068 auto IsNAC = [](SmallVectorImpl<Value *> &Objects) {
2069 return std::all_of(Objects.begin(), Objects.end(),
2070 [](Value *V){ return isNoAliasCall(V); });
2073 // Is the set of underlying objects all things which must be disjoint from
2074 // noalias calls. For allocas, we consider only static ones (dynamic
2075 // allocas might be transformed into calls to malloc not simultaneously
2076 // live with the compared-to allocation). For globals, we exclude symbols
2077 // that might be resolve lazily to symbols in another dynamically-loaded
2078 // library (and, thus, could be malloc'ed by the implementation).
2079 auto IsAllocDisjoint = [](SmallVectorImpl<Value *> &Objects) {
2080 return std::all_of(Objects.begin(), Objects.end(),
2082 if (const AllocaInst *AI = dyn_cast<AllocaInst>(V))
2083 return AI->getParent() && AI->getParent()->getParent() &&
2084 AI->isStaticAlloca();
2085 if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
2086 return (GV->hasLocalLinkage() ||
2087 GV->hasHiddenVisibility() ||
2088 GV->hasProtectedVisibility() ||
2089 GV->hasUnnamedAddr()) &&
2090 !GV->isThreadLocal();
2091 if (const Argument *A = dyn_cast<Argument>(V))
2092 return A->hasByValAttr();
2097 if ((IsNAC(LHSUObjs) && IsAllocDisjoint(RHSUObjs)) ||
2098 (IsNAC(RHSUObjs) && IsAllocDisjoint(LHSUObjs)))
2099 return ConstantInt::get(GetCompareTy(LHS),
2100 !CmpInst::isTrueWhenEqual(Pred));
2107 /// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
2108 /// fold the result. If not, this returns null.
2109 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2110 const Query &Q, unsigned MaxRecurse) {
2111 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
2112 assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
2114 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
2115 if (Constant *CRHS = dyn_cast<Constant>(RHS))
2116 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
2118 // If we have a constant, make sure it is on the RHS.
2119 std::swap(LHS, RHS);
2120 Pred = CmpInst::getSwappedPredicate(Pred);
2123 Type *ITy = GetCompareTy(LHS); // The return type.
2124 Type *OpTy = LHS->getType(); // The operand type.
2126 // icmp X, X -> true/false
2127 // X icmp undef -> true/false. For example, icmp ugt %X, undef -> false
2128 // because X could be 0.
2129 if (LHS == RHS || isa<UndefValue>(RHS))
2130 return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
2132 // Special case logic when the operands have i1 type.
2133 if (OpTy->getScalarType()->isIntegerTy(1)) {
2136 case ICmpInst::ICMP_EQ:
2138 if (match(RHS, m_One()))
2141 case ICmpInst::ICMP_NE:
2143 if (match(RHS, m_Zero()))
2146 case ICmpInst::ICMP_UGT:
2148 if (match(RHS, m_Zero()))
2151 case ICmpInst::ICMP_UGE:
2153 if (match(RHS, m_One()))
2156 case ICmpInst::ICMP_SLT:
2158 if (match(RHS, m_Zero()))
2161 case ICmpInst::ICMP_SLE:
2163 if (match(RHS, m_One()))
2169 // If we are comparing with zero then try hard since this is a common case.
2170 if (match(RHS, m_Zero())) {
2171 bool LHSKnownNonNegative, LHSKnownNegative;
2173 default: llvm_unreachable("Unknown ICmp predicate!");
2174 case ICmpInst::ICMP_ULT:
2175 return getFalse(ITy);
2176 case ICmpInst::ICMP_UGE:
2177 return getTrue(ITy);
2178 case ICmpInst::ICMP_EQ:
2179 case ICmpInst::ICMP_ULE:
2180 if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2181 return getFalse(ITy);
2183 case ICmpInst::ICMP_NE:
2184 case ICmpInst::ICMP_UGT:
2185 if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2186 return getTrue(ITy);
2188 case ICmpInst::ICMP_SLT:
2189 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL, 0, Q.AC,
2191 if (LHSKnownNegative)
2192 return getTrue(ITy);
2193 if (LHSKnownNonNegative)
2194 return getFalse(ITy);
2196 case ICmpInst::ICMP_SLE:
2197 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL, 0, Q.AC,
2199 if (LHSKnownNegative)
2200 return getTrue(ITy);
2201 if (LHSKnownNonNegative &&
2202 isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2203 return getFalse(ITy);
2205 case ICmpInst::ICMP_SGE:
2206 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL, 0, Q.AC,
2208 if (LHSKnownNegative)
2209 return getFalse(ITy);
2210 if (LHSKnownNonNegative)
2211 return getTrue(ITy);
2213 case ICmpInst::ICMP_SGT:
2214 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL, 0, Q.AC,
2216 if (LHSKnownNegative)
2217 return getFalse(ITy);
2218 if (LHSKnownNonNegative &&
2219 isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2220 return getTrue(ITy);
2225 // See if we are doing a comparison with a constant integer.
2226 if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2227 // Rule out tautological comparisons (eg., ult 0 or uge 0).
2228 ConstantRange RHS_CR = ICmpInst::makeConstantRange(Pred, CI->getValue());
2229 if (RHS_CR.isEmptySet())
2230 return ConstantInt::getFalse(CI->getContext());
2231 if (RHS_CR.isFullSet())
2232 return ConstantInt::getTrue(CI->getContext());
2234 // Many binary operators with constant RHS have easy to compute constant
2235 // range. Use them to check whether the comparison is a tautology.
2236 unsigned Width = CI->getBitWidth();
2237 APInt Lower = APInt(Width, 0);
2238 APInt Upper = APInt(Width, 0);
2240 if (match(LHS, m_URem(m_Value(), m_ConstantInt(CI2)))) {
2241 // 'urem x, CI2' produces [0, CI2).
2242 Upper = CI2->getValue();
2243 } else if (match(LHS, m_SRem(m_Value(), m_ConstantInt(CI2)))) {
2244 // 'srem x, CI2' produces (-|CI2|, |CI2|).
2245 Upper = CI2->getValue().abs();
2246 Lower = (-Upper) + 1;
2247 } else if (match(LHS, m_UDiv(m_ConstantInt(CI2), m_Value()))) {
2248 // 'udiv CI2, x' produces [0, CI2].
2249 Upper = CI2->getValue() + 1;
2250 } else if (match(LHS, m_UDiv(m_Value(), m_ConstantInt(CI2)))) {
2251 // 'udiv x, CI2' produces [0, UINT_MAX / CI2].
2252 APInt NegOne = APInt::getAllOnesValue(Width);
2254 Upper = NegOne.udiv(CI2->getValue()) + 1;
2255 } else if (match(LHS, m_SDiv(m_ConstantInt(CI2), m_Value()))) {
2256 if (CI2->isMinSignedValue()) {
2257 // 'sdiv INT_MIN, x' produces [INT_MIN, INT_MIN / -2].
2258 Lower = CI2->getValue();
2259 Upper = Lower.lshr(1) + 1;
2261 // 'sdiv CI2, x' produces [-|CI2|, |CI2|].
2262 Upper = CI2->getValue().abs() + 1;
2263 Lower = (-Upper) + 1;
2265 } else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) {
2266 APInt IntMin = APInt::getSignedMinValue(Width);
2267 APInt IntMax = APInt::getSignedMaxValue(Width);
2268 APInt Val = CI2->getValue();
2269 if (Val.isAllOnesValue()) {
2270 // 'sdiv x, -1' produces [INT_MIN + 1, INT_MAX]
2271 // where CI2 != -1 and CI2 != 0 and CI2 != 1
2274 } else if (Val.countLeadingZeros() < Width - 1) {
2275 // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2]
2276 // where CI2 != -1 and CI2 != 0 and CI2 != 1
2277 Lower = IntMin.sdiv(Val);
2278 Upper = IntMax.sdiv(Val);
2279 if (Lower.sgt(Upper))
2280 std::swap(Lower, Upper);
2282 assert(Upper != Lower && "Upper part of range has wrapped!");
2284 } else if (match(LHS, m_NUWShl(m_ConstantInt(CI2), m_Value()))) {
2285 // 'shl nuw CI2, x' produces [CI2, CI2 << CLZ(CI2)]
2286 Lower = CI2->getValue();
2287 Upper = Lower.shl(Lower.countLeadingZeros()) + 1;
2288 } else if (match(LHS, m_NSWShl(m_ConstantInt(CI2), m_Value()))) {
2289 if (CI2->isNegative()) {
2290 // 'shl nsw CI2, x' produces [CI2 << CLO(CI2)-1, CI2]
2291 unsigned ShiftAmount = CI2->getValue().countLeadingOnes() - 1;
2292 Lower = CI2->getValue().shl(ShiftAmount);
2293 Upper = CI2->getValue() + 1;
2295 // 'shl nsw CI2, x' produces [CI2, CI2 << CLZ(CI2)-1]
2296 unsigned ShiftAmount = CI2->getValue().countLeadingZeros() - 1;
2297 Lower = CI2->getValue();
2298 Upper = CI2->getValue().shl(ShiftAmount) + 1;
2300 } else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) {
2301 // 'lshr x, CI2' produces [0, UINT_MAX >> CI2].
2302 APInt NegOne = APInt::getAllOnesValue(Width);
2303 if (CI2->getValue().ult(Width))
2304 Upper = NegOne.lshr(CI2->getValue()) + 1;
2305 } else if (match(LHS, m_LShr(m_ConstantInt(CI2), m_Value()))) {
2306 // 'lshr CI2, x' produces [CI2 >> (Width-1), CI2].
2307 unsigned ShiftAmount = Width - 1;
2308 if (!CI2->isZero() && cast<BinaryOperator>(LHS)->isExact())
2309 ShiftAmount = CI2->getValue().countTrailingZeros();
2310 Lower = CI2->getValue().lshr(ShiftAmount);
2311 Upper = CI2->getValue() + 1;
2312 } else if (match(LHS, m_AShr(m_Value(), m_ConstantInt(CI2)))) {
2313 // 'ashr x, CI2' produces [INT_MIN >> CI2, INT_MAX >> CI2].
2314 APInt IntMin = APInt::getSignedMinValue(Width);
2315 APInt IntMax = APInt::getSignedMaxValue(Width);
2316 if (CI2->getValue().ult(Width)) {
2317 Lower = IntMin.ashr(CI2->getValue());
2318 Upper = IntMax.ashr(CI2->getValue()) + 1;
2320 } else if (match(LHS, m_AShr(m_ConstantInt(CI2), m_Value()))) {
2321 unsigned ShiftAmount = Width - 1;
2322 if (!CI2->isZero() && cast<BinaryOperator>(LHS)->isExact())
2323 ShiftAmount = CI2->getValue().countTrailingZeros();
2324 if (CI2->isNegative()) {
2325 // 'ashr CI2, x' produces [CI2, CI2 >> (Width-1)]
2326 Lower = CI2->getValue();
2327 Upper = CI2->getValue().ashr(ShiftAmount) + 1;
2329 // 'ashr CI2, x' produces [CI2 >> (Width-1), CI2]
2330 Lower = CI2->getValue().ashr(ShiftAmount);
2331 Upper = CI2->getValue() + 1;
2333 } else if (match(LHS, m_Or(m_Value(), m_ConstantInt(CI2)))) {
2334 // 'or x, CI2' produces [CI2, UINT_MAX].
2335 Lower = CI2->getValue();
2336 } else if (match(LHS, m_And(m_Value(), m_ConstantInt(CI2)))) {
2337 // 'and x, CI2' produces [0, CI2].
2338 Upper = CI2->getValue() + 1;
2340 if (Lower != Upper) {
2341 ConstantRange LHS_CR = ConstantRange(Lower, Upper);
2342 if (RHS_CR.contains(LHS_CR))
2343 return ConstantInt::getTrue(RHS->getContext());
2344 if (RHS_CR.inverse().contains(LHS_CR))
2345 return ConstantInt::getFalse(RHS->getContext());
2349 // Compare of cast, for example (zext X) != 0 -> X != 0
2350 if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
2351 Instruction *LI = cast<CastInst>(LHS);
2352 Value *SrcOp = LI->getOperand(0);
2353 Type *SrcTy = SrcOp->getType();
2354 Type *DstTy = LI->getType();
2356 // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
2357 // if the integer type is the same size as the pointer type.
2358 if (MaxRecurse && Q.DL && isa<PtrToIntInst>(LI) &&
2359 Q.DL->getTypeSizeInBits(SrcTy) == DstTy->getPrimitiveSizeInBits()) {
2360 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
2361 // Transfer the cast to the constant.
2362 if (Value *V = SimplifyICmpInst(Pred, SrcOp,
2363 ConstantExpr::getIntToPtr(RHSC, SrcTy),
2366 } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
2367 if (RI->getOperand(0)->getType() == SrcTy)
2368 // Compare without the cast.
2369 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2375 if (isa<ZExtInst>(LHS)) {
2376 // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
2378 if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
2379 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2380 // Compare X and Y. Note that signed predicates become unsigned.
2381 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
2382 SrcOp, RI->getOperand(0), Q,
2386 // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
2387 // too. If not, then try to deduce the result of the comparison.
2388 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2389 // Compute the constant that would happen if we truncated to SrcTy then
2390 // reextended to DstTy.
2391 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2392 Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
2394 // If the re-extended constant didn't change then this is effectively
2395 // also a case of comparing two zero-extended values.
2396 if (RExt == CI && MaxRecurse)
2397 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
2398 SrcOp, Trunc, Q, MaxRecurse-1))
2401 // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
2402 // there. Use this to work out the result of the comparison.
2405 default: llvm_unreachable("Unknown ICmp predicate!");
2407 case ICmpInst::ICMP_EQ:
2408 case ICmpInst::ICMP_UGT:
2409 case ICmpInst::ICMP_UGE:
2410 return ConstantInt::getFalse(CI->getContext());
2412 case ICmpInst::ICMP_NE:
2413 case ICmpInst::ICMP_ULT:
2414 case ICmpInst::ICMP_ULE:
2415 return ConstantInt::getTrue(CI->getContext());
2417 // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
2418 // is non-negative then LHS <s RHS.
2419 case ICmpInst::ICMP_SGT:
2420 case ICmpInst::ICMP_SGE:
2421 return CI->getValue().isNegative() ?
2422 ConstantInt::getTrue(CI->getContext()) :
2423 ConstantInt::getFalse(CI->getContext());
2425 case ICmpInst::ICMP_SLT:
2426 case ICmpInst::ICMP_SLE:
2427 return CI->getValue().isNegative() ?
2428 ConstantInt::getFalse(CI->getContext()) :
2429 ConstantInt::getTrue(CI->getContext());
2435 if (isa<SExtInst>(LHS)) {
2436 // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
2438 if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
2439 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2440 // Compare X and Y. Note that the predicate does not change.
2441 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2445 // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
2446 // too. If not, then try to deduce the result of the comparison.
2447 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2448 // Compute the constant that would happen if we truncated to SrcTy then
2449 // reextended to DstTy.
2450 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2451 Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
2453 // If the re-extended constant didn't change then this is effectively
2454 // also a case of comparing two sign-extended values.
2455 if (RExt == CI && MaxRecurse)
2456 if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
2459 // Otherwise the upper bits of LHS are all equal, while RHS has varying
2460 // bits there. Use this to work out the result of the comparison.
2463 default: llvm_unreachable("Unknown ICmp predicate!");
2464 case ICmpInst::ICMP_EQ:
2465 return ConstantInt::getFalse(CI->getContext());
2466 case ICmpInst::ICMP_NE:
2467 return ConstantInt::getTrue(CI->getContext());
2469 // If RHS is non-negative then LHS <s RHS. If RHS is negative then
2471 case ICmpInst::ICMP_SGT:
2472 case ICmpInst::ICMP_SGE:
2473 return CI->getValue().isNegative() ?
2474 ConstantInt::getTrue(CI->getContext()) :
2475 ConstantInt::getFalse(CI->getContext());
2476 case ICmpInst::ICMP_SLT:
2477 case ICmpInst::ICMP_SLE:
2478 return CI->getValue().isNegative() ?
2479 ConstantInt::getFalse(CI->getContext()) :
2480 ConstantInt::getTrue(CI->getContext());
2482 // If LHS is non-negative then LHS <u RHS. If LHS is negative then
2484 case ICmpInst::ICMP_UGT:
2485 case ICmpInst::ICMP_UGE:
2486 // Comparison is true iff the LHS <s 0.
2488 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
2489 Constant::getNullValue(SrcTy),
2493 case ICmpInst::ICMP_ULT:
2494 case ICmpInst::ICMP_ULE:
2495 // Comparison is true iff the LHS >=s 0.
2497 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
2498 Constant::getNullValue(SrcTy),
2508 // Special logic for binary operators.
2509 BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
2510 BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
2511 if (MaxRecurse && (LBO || RBO)) {
2512 // Analyze the case when either LHS or RHS is an add instruction.
2513 Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
2514 // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
2515 bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
2516 if (LBO && LBO->getOpcode() == Instruction::Add) {
2517 A = LBO->getOperand(0); B = LBO->getOperand(1);
2518 NoLHSWrapProblem = ICmpInst::isEquality(Pred) ||
2519 (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
2520 (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
2522 if (RBO && RBO->getOpcode() == Instruction::Add) {
2523 C = RBO->getOperand(0); D = RBO->getOperand(1);
2524 NoRHSWrapProblem = ICmpInst::isEquality(Pred) ||
2525 (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
2526 (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
2529 // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
2530 if ((A == RHS || B == RHS) && NoLHSWrapProblem)
2531 if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
2532 Constant::getNullValue(RHS->getType()),
2536 // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
2537 if ((C == LHS || D == LHS) && NoRHSWrapProblem)
2538 if (Value *V = SimplifyICmpInst(Pred,
2539 Constant::getNullValue(LHS->getType()),
2540 C == LHS ? D : C, Q, MaxRecurse-1))
2543 // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
2544 if (A && C && (A == C || A == D || B == C || B == D) &&
2545 NoLHSWrapProblem && NoRHSWrapProblem) {
2546 // Determine Y and Z in the form icmp (X+Y), (X+Z).
2549 // C + B == C + D -> B == D
2552 } else if (A == D) {
2553 // D + B == C + D -> B == C
2556 } else if (B == C) {
2557 // A + C == C + D -> A == D
2562 // A + D == C + D -> A == C
2566 if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse-1))
2571 // icmp pred (or X, Y), X
2572 if (LBO && match(LBO, m_CombineOr(m_Or(m_Value(), m_Specific(RHS)),
2573 m_Or(m_Specific(RHS), m_Value())))) {
2574 if (Pred == ICmpInst::ICMP_ULT)
2575 return getFalse(ITy);
2576 if (Pred == ICmpInst::ICMP_UGE)
2577 return getTrue(ITy);
2579 // icmp pred X, (or X, Y)
2580 if (RBO && match(RBO, m_CombineOr(m_Or(m_Value(), m_Specific(LHS)),
2581 m_Or(m_Specific(LHS), m_Value())))) {
2582 if (Pred == ICmpInst::ICMP_ULE)
2583 return getTrue(ITy);
2584 if (Pred == ICmpInst::ICMP_UGT)
2585 return getFalse(ITy);
2588 // icmp pred (and X, Y), X
2589 if (LBO && match(LBO, m_CombineOr(m_And(m_Value(), m_Specific(RHS)),
2590 m_And(m_Specific(RHS), m_Value())))) {
2591 if (Pred == ICmpInst::ICMP_UGT)
2592 return getFalse(ITy);
2593 if (Pred == ICmpInst::ICMP_ULE)
2594 return getTrue(ITy);
2596 // icmp pred X, (and X, Y)
2597 if (RBO && match(RBO, m_CombineOr(m_And(m_Value(), m_Specific(LHS)),
2598 m_And(m_Specific(LHS), m_Value())))) {
2599 if (Pred == ICmpInst::ICMP_UGE)
2600 return getTrue(ITy);
2601 if (Pred == ICmpInst::ICMP_ULT)
2602 return getFalse(ITy);
2605 // 0 - (zext X) pred C
2606 if (!CmpInst::isUnsigned(Pred) && match(LHS, m_Neg(m_ZExt(m_Value())))) {
2607 if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS)) {
2608 if (RHSC->getValue().isStrictlyPositive()) {
2609 if (Pred == ICmpInst::ICMP_SLT)
2610 return ConstantInt::getTrue(RHSC->getContext());
2611 if (Pred == ICmpInst::ICMP_SGE)
2612 return ConstantInt::getFalse(RHSC->getContext());
2613 if (Pred == ICmpInst::ICMP_EQ)
2614 return ConstantInt::getFalse(RHSC->getContext());
2615 if (Pred == ICmpInst::ICMP_NE)
2616 return ConstantInt::getTrue(RHSC->getContext());
2618 if (RHSC->getValue().isNonNegative()) {
2619 if (Pred == ICmpInst::ICMP_SLE)
2620 return ConstantInt::getTrue(RHSC->getContext());
2621 if (Pred == ICmpInst::ICMP_SGT)
2622 return ConstantInt::getFalse(RHSC->getContext());
2627 // icmp pred (urem X, Y), Y
2628 if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
2629 bool KnownNonNegative, KnownNegative;
2633 case ICmpInst::ICMP_SGT:
2634 case ICmpInst::ICMP_SGE:
2635 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.DL, 0, Q.AC,
2637 if (!KnownNonNegative)
2640 case ICmpInst::ICMP_EQ:
2641 case ICmpInst::ICMP_UGT:
2642 case ICmpInst::ICMP_UGE:
2643 return getFalse(ITy);
2644 case ICmpInst::ICMP_SLT:
2645 case ICmpInst::ICMP_SLE:
2646 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.DL, 0, Q.AC,
2648 if (!KnownNonNegative)
2651 case ICmpInst::ICMP_NE:
2652 case ICmpInst::ICMP_ULT:
2653 case ICmpInst::ICMP_ULE:
2654 return getTrue(ITy);
2658 // icmp pred X, (urem Y, X)
2659 if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
2660 bool KnownNonNegative, KnownNegative;
2664 case ICmpInst::ICMP_SGT:
2665 case ICmpInst::ICMP_SGE:
2666 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.DL, 0, Q.AC,
2668 if (!KnownNonNegative)
2671 case ICmpInst::ICMP_NE:
2672 case ICmpInst::ICMP_UGT:
2673 case ICmpInst::ICMP_UGE:
2674 return getTrue(ITy);
2675 case ICmpInst::ICMP_SLT:
2676 case ICmpInst::ICMP_SLE:
2677 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.DL, 0, Q.AC,
2679 if (!KnownNonNegative)
2682 case ICmpInst::ICMP_EQ:
2683 case ICmpInst::ICMP_ULT:
2684 case ICmpInst::ICMP_ULE:
2685 return getFalse(ITy);
2690 if (LBO && match(LBO, m_UDiv(m_Specific(RHS), m_Value()))) {
2691 // icmp pred (X /u Y), X
2692 if (Pred == ICmpInst::ICMP_UGT)
2693 return getFalse(ITy);
2694 if (Pred == ICmpInst::ICMP_ULE)
2695 return getTrue(ITy);
2702 // where CI2 is a power of 2 and CI isn't
2703 if (auto *CI = dyn_cast<ConstantInt>(RHS)) {
2704 const APInt *CI2Val, *CIVal = &CI->getValue();
2705 if (LBO && match(LBO, m_Shl(m_APInt(CI2Val), m_Value())) &&
2706 CI2Val->isPowerOf2()) {
2707 if (!CIVal->isPowerOf2()) {
2708 // CI2 << X can equal zero in some circumstances,
2709 // this simplification is unsafe if CI is zero.
2711 // We know it is safe if:
2712 // - The shift is nsw, we can't shift out the one bit.
2713 // - The shift is nuw, we can't shift out the one bit.
2716 if (LBO->hasNoSignedWrap() || LBO->hasNoUnsignedWrap() ||
2717 *CI2Val == 1 || !CI->isZero()) {
2718 if (Pred == ICmpInst::ICMP_EQ)
2719 return ConstantInt::getFalse(RHS->getContext());
2720 if (Pred == ICmpInst::ICMP_NE)
2721 return ConstantInt::getTrue(RHS->getContext());
2724 if (CIVal->isSignBit() && *CI2Val == 1) {
2725 if (Pred == ICmpInst::ICMP_UGT)
2726 return ConstantInt::getFalse(RHS->getContext());
2727 if (Pred == ICmpInst::ICMP_ULE)
2728 return ConstantInt::getTrue(RHS->getContext());
2733 if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
2734 LBO->getOperand(1) == RBO->getOperand(1)) {
2735 switch (LBO->getOpcode()) {
2737 case Instruction::UDiv:
2738 case Instruction::LShr:
2739 if (ICmpInst::isSigned(Pred))
2742 case Instruction::SDiv:
2743 case Instruction::AShr:
2744 if (!LBO->isExact() || !RBO->isExact())
2746 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2747 RBO->getOperand(0), Q, MaxRecurse-1))
2750 case Instruction::Shl: {
2751 bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
2752 bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
2755 if (!NSW && ICmpInst::isSigned(Pred))
2757 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2758 RBO->getOperand(0), Q, MaxRecurse-1))
2765 // Simplify comparisons involving max/min.
2767 CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE;
2768 CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
2770 // Signed variants on "max(a,b)>=a -> true".
2771 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2772 if (A != RHS) std::swap(A, B); // smax(A, B) pred A.
2773 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2774 // We analyze this as smax(A, B) pred A.
2776 } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
2777 (A == LHS || B == LHS)) {
2778 if (A != LHS) std::swap(A, B); // A pred smax(A, B).
2779 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2780 // We analyze this as smax(A, B) swapped-pred A.
2781 P = CmpInst::getSwappedPredicate(Pred);
2782 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2783 (A == RHS || B == RHS)) {
2784 if (A != RHS) std::swap(A, B); // smin(A, B) pred A.
2785 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2786 // We analyze this as smax(-A, -B) swapped-pred -A.
2787 // Note that we do not need to actually form -A or -B thanks to EqP.
2788 P = CmpInst::getSwappedPredicate(Pred);
2789 } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
2790 (A == LHS || B == LHS)) {
2791 if (A != LHS) std::swap(A, B); // A pred smin(A, B).
2792 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2793 // We analyze this as smax(-A, -B) pred -A.
2794 // Note that we do not need to actually form -A or -B thanks to EqP.
2797 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2798 // Cases correspond to "max(A, B) p A".
2802 case CmpInst::ICMP_EQ:
2803 case CmpInst::ICMP_SLE:
2804 // Equivalent to "A EqP B". This may be the same as the condition tested
2805 // in the max/min; if so, we can just return that.
2806 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2808 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2810 // Otherwise, see if "A EqP B" simplifies.
2812 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2815 case CmpInst::ICMP_NE:
2816 case CmpInst::ICMP_SGT: {
2817 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2818 // Equivalent to "A InvEqP B". This may be the same as the condition
2819 // tested in the max/min; if so, we can just return that.
2820 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2822 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2824 // Otherwise, see if "A InvEqP B" simplifies.
2826 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2830 case CmpInst::ICMP_SGE:
2832 return getTrue(ITy);
2833 case CmpInst::ICMP_SLT:
2835 return getFalse(ITy);
2839 // Unsigned variants on "max(a,b)>=a -> true".
2840 P = CmpInst::BAD_ICMP_PREDICATE;
2841 if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2842 if (A != RHS) std::swap(A, B); // umax(A, B) pred A.
2843 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2844 // We analyze this as umax(A, B) pred A.
2846 } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
2847 (A == LHS || B == LHS)) {
2848 if (A != LHS) std::swap(A, B); // A pred umax(A, B).
2849 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2850 // We analyze this as umax(A, B) swapped-pred A.
2851 P = CmpInst::getSwappedPredicate(Pred);
2852 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2853 (A == RHS || B == RHS)) {
2854 if (A != RHS) std::swap(A, B); // umin(A, B) pred A.
2855 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2856 // We analyze this as umax(-A, -B) swapped-pred -A.
2857 // Note that we do not need to actually form -A or -B thanks to EqP.
2858 P = CmpInst::getSwappedPredicate(Pred);
2859 } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
2860 (A == LHS || B == LHS)) {
2861 if (A != LHS) std::swap(A, B); // A pred umin(A, B).
2862 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2863 // We analyze this as umax(-A, -B) pred -A.
2864 // Note that we do not need to actually form -A or -B thanks to EqP.
2867 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2868 // Cases correspond to "max(A, B) p A".
2872 case CmpInst::ICMP_EQ:
2873 case CmpInst::ICMP_ULE:
2874 // Equivalent to "A EqP B". This may be the same as the condition tested
2875 // in the max/min; if so, we can just return that.
2876 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2878 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2880 // Otherwise, see if "A EqP B" simplifies.
2882 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2885 case CmpInst::ICMP_NE:
2886 case CmpInst::ICMP_UGT: {
2887 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2888 // Equivalent to "A InvEqP B". This may be the same as the condition
2889 // tested in the max/min; if so, we can just return that.
2890 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2892 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2894 // Otherwise, see if "A InvEqP B" simplifies.
2896 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2900 case CmpInst::ICMP_UGE:
2902 return getTrue(ITy);
2903 case CmpInst::ICMP_ULT:
2905 return getFalse(ITy);
2909 // Variants on "max(x,y) >= min(x,z)".
2911 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
2912 match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
2913 (A == C || A == D || B == C || B == D)) {
2914 // max(x, ?) pred min(x, ?).
2915 if (Pred == CmpInst::ICMP_SGE)
2917 return getTrue(ITy);
2918 if (Pred == CmpInst::ICMP_SLT)
2920 return getFalse(ITy);
2921 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2922 match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
2923 (A == C || A == D || B == C || B == D)) {
2924 // min(x, ?) pred max(x, ?).
2925 if (Pred == CmpInst::ICMP_SLE)
2927 return getTrue(ITy);
2928 if (Pred == CmpInst::ICMP_SGT)
2930 return getFalse(ITy);
2931 } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
2932 match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
2933 (A == C || A == D || B == C || B == D)) {
2934 // max(x, ?) pred min(x, ?).
2935 if (Pred == CmpInst::ICMP_UGE)
2937 return getTrue(ITy);
2938 if (Pred == CmpInst::ICMP_ULT)
2940 return getFalse(ITy);
2941 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2942 match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
2943 (A == C || A == D || B == C || B == D)) {
2944 // min(x, ?) pred max(x, ?).
2945 if (Pred == CmpInst::ICMP_ULE)
2947 return getTrue(ITy);
2948 if (Pred == CmpInst::ICMP_UGT)
2950 return getFalse(ITy);
2953 // Simplify comparisons of related pointers using a powerful, recursive
2954 // GEP-walk when we have target data available..
2955 if (LHS->getType()->isPointerTy())
2956 if (Constant *C = computePointerICmp(Q.DL, Q.TLI, Pred, LHS, RHS))
2959 if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
2960 if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
2961 if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
2962 GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
2963 (ICmpInst::isEquality(Pred) ||
2964 (GLHS->isInBounds() && GRHS->isInBounds() &&
2965 Pred == ICmpInst::getSignedPredicate(Pred)))) {
2966 // The bases are equal and the indices are constant. Build a constant
2967 // expression GEP with the same indices and a null base pointer to see
2968 // what constant folding can make out of it.
2969 Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
2970 SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
2971 Constant *NewLHS = ConstantExpr::getGetElementPtr(Null, IndicesLHS);
2973 SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
2974 Constant *NewRHS = ConstantExpr::getGetElementPtr(Null, IndicesRHS);
2975 return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
2980 // If a bit is known to be zero for A and known to be one for B,
2981 // then A and B cannot be equal.
2982 if (ICmpInst::isEquality(Pred)) {
2983 if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2984 uint32_t BitWidth = CI->getBitWidth();
2985 APInt LHSKnownZero(BitWidth, 0);
2986 APInt LHSKnownOne(BitWidth, 0);
2987 computeKnownBits(LHS, LHSKnownZero, LHSKnownOne, Q.DL, /*Depth=*/0, Q.AC,
2989 const APInt &RHSVal = CI->getValue();
2990 if (((LHSKnownZero & RHSVal) != 0) || ((LHSKnownOne & ~RHSVal) != 0))
2991 return Pred == ICmpInst::ICMP_EQ
2992 ? ConstantInt::getFalse(CI->getContext())
2993 : ConstantInt::getTrue(CI->getContext());
2997 // If the comparison is with the result of a select instruction, check whether
2998 // comparing with either branch of the select always yields the same value.
2999 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3000 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
3003 // If the comparison is with the result of a phi instruction, check whether
3004 // doing the compare with each incoming phi value yields a common result.
3005 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3006 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
3012 Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3013 const DataLayout *DL,
3014 const TargetLibraryInfo *TLI,
3015 const DominatorTree *DT, AssumptionCache *AC,
3016 Instruction *CxtI) {
3017 return ::SimplifyICmpInst(Predicate, LHS, RHS, Query(DL, TLI, DT, AC, CxtI),
3021 /// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can
3022 /// fold the result. If not, this returns null.
3023 static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3024 const Query &Q, unsigned MaxRecurse) {
3025 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
3026 assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
3028 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
3029 if (Constant *CRHS = dyn_cast<Constant>(RHS))
3030 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
3032 // If we have a constant, make sure it is on the RHS.
3033 std::swap(LHS, RHS);
3034 Pred = CmpInst::getSwappedPredicate(Pred);
3037 // Fold trivial predicates.
3038 if (Pred == FCmpInst::FCMP_FALSE)
3039 return ConstantInt::get(GetCompareTy(LHS), 0);
3040 if (Pred == FCmpInst::FCMP_TRUE)
3041 return ConstantInt::get(GetCompareTy(LHS), 1);
3043 if (isa<UndefValue>(RHS)) // fcmp pred X, undef -> undef
3044 return UndefValue::get(GetCompareTy(LHS));
3046 // fcmp x,x -> true/false. Not all compares are foldable.
3048 if (CmpInst::isTrueWhenEqual(Pred))
3049 return ConstantInt::get(GetCompareTy(LHS), 1);
3050 if (CmpInst::isFalseWhenEqual(Pred))
3051 return ConstantInt::get(GetCompareTy(LHS), 0);
3054 // Handle fcmp with constant RHS
3055 if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHS)) {
3056 // If the constant is a nan, see if we can fold the comparison based on it.
3057 if (CFP->getValueAPF().isNaN()) {
3058 if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo"
3059 return ConstantInt::getFalse(CFP->getContext());
3060 assert(FCmpInst::isUnordered(Pred) &&
3061 "Comparison must be either ordered or unordered!");
3062 // True if unordered.
3063 return ConstantInt::getTrue(CFP->getContext());
3065 // Check whether the constant is an infinity.
3066 if (CFP->getValueAPF().isInfinity()) {
3067 if (CFP->getValueAPF().isNegative()) {
3069 case FCmpInst::FCMP_OLT:
3070 // No value is ordered and less than negative infinity.
3071 return ConstantInt::getFalse(CFP->getContext());
3072 case FCmpInst::FCMP_UGE:
3073 // All values are unordered with or at least negative infinity.
3074 return ConstantInt::getTrue(CFP->getContext());
3080 case FCmpInst::FCMP_OGT:
3081 // No value is ordered and greater than infinity.
3082 return ConstantInt::getFalse(CFP->getContext());
3083 case FCmpInst::FCMP_ULE:
3084 // All values are unordered with and at most infinity.
3085 return ConstantInt::getTrue(CFP->getContext());
3091 if (CFP->getValueAPF().isZero()) {
3093 case FCmpInst::FCMP_UGE:
3094 if (CannotBeOrderedLessThanZero(LHS))
3095 return ConstantInt::getTrue(CFP->getContext());
3097 case FCmpInst::FCMP_OLT:
3099 if (CannotBeOrderedLessThanZero(LHS))
3100 return ConstantInt::getFalse(CFP->getContext());
3108 // If the comparison is with the result of a select instruction, check whether
3109 // comparing with either branch of the select always yields the same value.
3110 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3111 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
3114 // If the comparison is with the result of a phi instruction, check whether
3115 // doing the compare with each incoming phi value yields a common result.
3116 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3117 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
3123 Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3124 const DataLayout *DL,
3125 const TargetLibraryInfo *TLI,
3126 const DominatorTree *DT, AssumptionCache *AC,
3127 const Instruction *CxtI) {
3128 return ::SimplifyFCmpInst(Predicate, LHS, RHS, Query(DL, TLI, DT, AC, CxtI),
3132 /// SimplifySelectInst - Given operands for a SelectInst, see if we can fold
3133 /// the result. If not, this returns null.
3134 static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal,
3135 Value *FalseVal, const Query &Q,
3136 unsigned MaxRecurse) {
3137 // select true, X, Y -> X
3138 // select false, X, Y -> Y
3139 if (Constant *CB = dyn_cast<Constant>(CondVal)) {
3140 if (CB->isAllOnesValue())
3142 if (CB->isNullValue())
3146 // select C, X, X -> X
3147 if (TrueVal == FalseVal)
3150 if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y
3151 if (isa<Constant>(TrueVal))
3155 if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X
3157 if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
3160 const auto *ICI = dyn_cast<ICmpInst>(CondVal);
3161 unsigned BitWidth = TrueVal->getType()->getScalarSizeInBits();
3162 if (ICI && BitWidth) {
3163 ICmpInst::Predicate Pred = ICI->getPredicate();
3164 APInt MinSignedValue = APInt::getSignBit(BitWidth);
3168 bool IsBitTest = false;
3169 if (ICmpInst::isEquality(Pred) &&
3170 match(ICI->getOperand(0), m_And(m_Value(X), m_APInt(Y))) &&
3171 match(ICI->getOperand(1), m_Zero())) {
3173 TrueWhenUnset = Pred == ICmpInst::ICMP_EQ;
3174 } else if (Pred == ICmpInst::ICMP_SLT &&
3175 match(ICI->getOperand(1), m_Zero())) {
3176 X = ICI->getOperand(0);
3177 Y = &MinSignedValue;
3179 TrueWhenUnset = false;
3180 } else if (Pred == ICmpInst::ICMP_SGT &&
3181 match(ICI->getOperand(1), m_AllOnes())) {
3182 X = ICI->getOperand(0);
3183 Y = &MinSignedValue;
3185 TrueWhenUnset = true;
3189 // (X & Y) == 0 ? X & ~Y : X --> X
3190 // (X & Y) != 0 ? X & ~Y : X --> X & ~Y
3191 if (FalseVal == X && match(TrueVal, m_And(m_Specific(X), m_APInt(C))) &&
3193 return TrueWhenUnset ? FalseVal : TrueVal;
3194 // (X & Y) == 0 ? X : X & ~Y --> X & ~Y
3195 // (X & Y) != 0 ? X : X & ~Y --> X
3196 if (TrueVal == X && match(FalseVal, m_And(m_Specific(X), m_APInt(C))) &&
3198 return TrueWhenUnset ? FalseVal : TrueVal;
3200 if (Y->isPowerOf2()) {
3201 // (X & Y) == 0 ? X | Y : X --> X | Y
3202 // (X & Y) != 0 ? X | Y : X --> X
3203 if (FalseVal == X && match(TrueVal, m_Or(m_Specific(X), m_APInt(C))) &&
3205 return TrueWhenUnset ? TrueVal : FalseVal;
3206 // (X & Y) == 0 ? X : X | Y --> X
3207 // (X & Y) != 0 ? X : X | Y --> X | Y
3208 if (TrueVal == X && match(FalseVal, m_Or(m_Specific(X), m_APInt(C))) &&
3210 return TrueWhenUnset ? TrueVal : FalseVal;
3218 Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
3219 const DataLayout *DL,
3220 const TargetLibraryInfo *TLI,
3221 const DominatorTree *DT, AssumptionCache *AC,
3222 const Instruction *CxtI) {
3223 return ::SimplifySelectInst(Cond, TrueVal, FalseVal,
3224 Query(DL, TLI, DT, AC, CxtI), RecursionLimit);
3227 /// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
3228 /// fold the result. If not, this returns null.
3229 static Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const Query &Q, unsigned) {
3230 // The type of the GEP pointer operand.
3231 PointerType *PtrTy = cast<PointerType>(Ops[0]->getType()->getScalarType());
3232 unsigned AS = PtrTy->getAddressSpace();
3234 // getelementptr P -> P.
3235 if (Ops.size() == 1)
3238 // Compute the (pointer) type returned by the GEP instruction.
3239 Type *LastType = GetElementPtrInst::getIndexedType(PtrTy, Ops.slice(1));
3240 Type *GEPTy = PointerType::get(LastType, AS);
3241 if (VectorType *VT = dyn_cast<VectorType>(Ops[0]->getType()))
3242 GEPTy = VectorType::get(GEPTy, VT->getNumElements());
3244 if (isa<UndefValue>(Ops[0]))
3245 return UndefValue::get(GEPTy);
3247 if (Ops.size() == 2) {
3248 // getelementptr P, 0 -> P.
3249 if (match(Ops[1], m_Zero()))
3252 Type *Ty = PtrTy->getElementType();
3253 if (Q.DL && Ty->isSized()) {
3256 uint64_t TyAllocSize = Q.DL->getTypeAllocSize(Ty);
3257 // getelementptr P, N -> P if P points to a type of zero size.
3258 if (TyAllocSize == 0)
3261 // The following transforms are only safe if the ptrtoint cast
3262 // doesn't truncate the pointers.
3263 if (Ops[1]->getType()->getScalarSizeInBits() ==
3264 Q.DL->getPointerSizeInBits(AS)) {
3265 auto PtrToIntOrZero = [GEPTy](Value *P) -> Value * {
3266 if (match(P, m_Zero()))
3267 return Constant::getNullValue(GEPTy);
3269 if (match(P, m_PtrToInt(m_Value(Temp))))
3270 if (Temp->getType() == GEPTy)
3275 // getelementptr V, (sub P, V) -> P if P points to a type of size 1.
3276 if (TyAllocSize == 1 &&
3277 match(Ops[1], m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0])))))
3278 if (Value *R = PtrToIntOrZero(P))
3281 // getelementptr V, (ashr (sub P, V), C) -> Q
3282 // if P points to a type of size 1 << C.
3284 m_AShr(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3285 m_ConstantInt(C))) &&
3286 TyAllocSize == 1ULL << C)
3287 if (Value *R = PtrToIntOrZero(P))
3290 // getelementptr V, (sdiv (sub P, V), C) -> Q
3291 // if P points to a type of size C.
3293 m_SDiv(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3294 m_SpecificInt(TyAllocSize))))
3295 if (Value *R = PtrToIntOrZero(P))
3301 // Check to see if this is constant foldable.
3302 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
3303 if (!isa<Constant>(Ops[i]))
3306 return ConstantExpr::getGetElementPtr(cast<Constant>(Ops[0]), Ops.slice(1));
3309 Value *llvm::SimplifyGEPInst(ArrayRef<Value *> Ops, const DataLayout *DL,
3310 const TargetLibraryInfo *TLI,
3311 const DominatorTree *DT, AssumptionCache *AC,
3312 const Instruction *CxtI) {
3313 return ::SimplifyGEPInst(Ops, Query(DL, TLI, DT, AC, CxtI), RecursionLimit);
3316 /// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we
3317 /// can fold the result. If not, this returns null.
3318 static Value *SimplifyInsertValueInst(Value *Agg, Value *Val,
3319 ArrayRef<unsigned> Idxs, const Query &Q,
3321 if (Constant *CAgg = dyn_cast<Constant>(Agg))
3322 if (Constant *CVal = dyn_cast<Constant>(Val))
3323 return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
3325 // insertvalue x, undef, n -> x
3326 if (match(Val, m_Undef()))
3329 // insertvalue x, (extractvalue y, n), n
3330 if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
3331 if (EV->getAggregateOperand()->getType() == Agg->getType() &&
3332 EV->getIndices() == Idxs) {
3333 // insertvalue undef, (extractvalue y, n), n -> y
3334 if (match(Agg, m_Undef()))
3335 return EV->getAggregateOperand();
3337 // insertvalue y, (extractvalue y, n), n -> y
3338 if (Agg == EV->getAggregateOperand())
3345 Value *llvm::SimplifyInsertValueInst(
3346 Value *Agg, Value *Val, ArrayRef<unsigned> Idxs, const DataLayout *DL,
3347 const TargetLibraryInfo *TLI, const DominatorTree *DT, AssumptionCache *AC,
3348 const Instruction *CxtI) {
3349 return ::SimplifyInsertValueInst(Agg, Val, Idxs, Query(DL, TLI, DT, AC, CxtI),
3353 /// SimplifyPHINode - See if we can fold the given phi. If not, returns null.
3354 static Value *SimplifyPHINode(PHINode *PN, const Query &Q) {
3355 // If all of the PHI's incoming values are the same then replace the PHI node
3356 // with the common value.
3357 Value *CommonValue = nullptr;
3358 bool HasUndefInput = false;
3359 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
3360 Value *Incoming = PN->getIncomingValue(i);
3361 // If the incoming value is the phi node itself, it can safely be skipped.
3362 if (Incoming == PN) continue;
3363 if (isa<UndefValue>(Incoming)) {
3364 // Remember that we saw an undef value, but otherwise ignore them.
3365 HasUndefInput = true;
3368 if (CommonValue && Incoming != CommonValue)
3369 return nullptr; // Not the same, bail out.
3370 CommonValue = Incoming;
3373 // If CommonValue is null then all of the incoming values were either undef or
3374 // equal to the phi node itself.
3376 return UndefValue::get(PN->getType());
3378 // If we have a PHI node like phi(X, undef, X), where X is defined by some
3379 // instruction, we cannot return X as the result of the PHI node unless it
3380 // dominates the PHI block.
3382 return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : nullptr;
3387 static Value *SimplifyTruncInst(Value *Op, Type *Ty, const Query &Q, unsigned) {
3388 if (Constant *C = dyn_cast<Constant>(Op))
3389 return ConstantFoldInstOperands(Instruction::Trunc, Ty, C, Q.DL, Q.TLI);
3394 Value *llvm::SimplifyTruncInst(Value *Op, Type *Ty, const DataLayout *DL,
3395 const TargetLibraryInfo *TLI,
3396 const DominatorTree *DT, AssumptionCache *AC,
3397 const Instruction *CxtI) {
3398 return ::SimplifyTruncInst(Op, Ty, Query(DL, TLI, DT, AC, CxtI),
3402 //=== Helper functions for higher up the class hierarchy.
3404 /// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
3405 /// fold the result. If not, this returns null.
3406 static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
3407 const Query &Q, unsigned MaxRecurse) {
3409 case Instruction::Add:
3410 return SimplifyAddInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
3412 case Instruction::FAdd:
3413 return SimplifyFAddInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3415 case Instruction::Sub:
3416 return SimplifySubInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
3418 case Instruction::FSub:
3419 return SimplifyFSubInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3421 case Instruction::Mul: return SimplifyMulInst (LHS, RHS, Q, MaxRecurse);
3422 case Instruction::FMul:
3423 return SimplifyFMulInst (LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3424 case Instruction::SDiv: return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
3425 case Instruction::UDiv: return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
3426 case Instruction::FDiv: return SimplifyFDivInst(LHS, RHS, Q, MaxRecurse);
3427 case Instruction::SRem: return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
3428 case Instruction::URem: return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
3429 case Instruction::FRem: return SimplifyFRemInst(LHS, RHS, Q, MaxRecurse);
3430 case Instruction::Shl:
3431 return SimplifyShlInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
3433 case Instruction::LShr:
3434 return SimplifyLShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
3435 case Instruction::AShr:
3436 return SimplifyAShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
3437 case Instruction::And: return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
3438 case Instruction::Or: return SimplifyOrInst (LHS, RHS, Q, MaxRecurse);
3439 case Instruction::Xor: return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
3441 if (Constant *CLHS = dyn_cast<Constant>(LHS))
3442 if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
3443 Constant *COps[] = {CLHS, CRHS};
3444 return ConstantFoldInstOperands(Opcode, LHS->getType(), COps, Q.DL,
3448 // If the operation is associative, try some generic simplifications.
3449 if (Instruction::isAssociative(Opcode))
3450 if (Value *V = SimplifyAssociativeBinOp(Opcode, LHS, RHS, Q, MaxRecurse))
3453 // If the operation is with the result of a select instruction check whether
3454 // operating on either branch of the select always yields the same value.
3455 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3456 if (Value *V = ThreadBinOpOverSelect(Opcode, LHS, RHS, Q, MaxRecurse))
3459 // If the operation is with the result of a phi instruction, check whether
3460 // operating on all incoming values of the phi always yields the same value.
3461 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3462 if (Value *V = ThreadBinOpOverPHI(Opcode, LHS, RHS, Q, MaxRecurse))
3469 /// SimplifyFPBinOp - Given operands for a BinaryOperator, see if we can
3470 /// fold the result. If not, this returns null.
3471 /// In contrast to SimplifyBinOp, try to use FastMathFlag when folding the
3472 /// result. In case we don't need FastMathFlags, simply fall to SimplifyBinOp.
3473 static Value *SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
3474 const FastMathFlags &FMF, const Query &Q,
3475 unsigned MaxRecurse) {
3477 case Instruction::FAdd:
3478 return SimplifyFAddInst(LHS, RHS, FMF, Q, MaxRecurse);
3479 case Instruction::FSub:
3480 return SimplifyFSubInst(LHS, RHS, FMF, Q, MaxRecurse);
3481 case Instruction::FMul:
3482 return SimplifyFMulInst(LHS, RHS, FMF, Q, MaxRecurse);
3484 return SimplifyBinOp(Opcode, LHS, RHS, Q, MaxRecurse);
3488 Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
3489 const DataLayout *DL, const TargetLibraryInfo *TLI,
3490 const DominatorTree *DT, AssumptionCache *AC,
3491 const Instruction *CxtI) {
3492 return ::SimplifyBinOp(Opcode, LHS, RHS, Query(DL, TLI, DT, AC, CxtI),
3496 Value *llvm::SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
3497 const FastMathFlags &FMF, const DataLayout *DL,
3498 const TargetLibraryInfo *TLI,
3499 const DominatorTree *DT, AssumptionCache *AC,
3500 const Instruction *CxtI) {
3501 return ::SimplifyFPBinOp(Opcode, LHS, RHS, FMF, Query(DL, TLI, DT, AC, CxtI),
3505 /// SimplifyCmpInst - Given operands for a CmpInst, see if we can
3506 /// fold the result.
3507 static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3508 const Query &Q, unsigned MaxRecurse) {
3509 if (CmpInst::isIntPredicate((CmpInst::Predicate)Predicate))
3510 return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
3511 return SimplifyFCmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
3514 Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3515 const DataLayout *DL, const TargetLibraryInfo *TLI,
3516 const DominatorTree *DT, AssumptionCache *AC,
3517 const Instruction *CxtI) {
3518 return ::SimplifyCmpInst(Predicate, LHS, RHS, Query(DL, TLI, DT, AC, CxtI),
3522 static bool IsIdempotent(Intrinsic::ID ID) {
3524 default: return false;
3526 // Unary idempotent: f(f(x)) = f(x)
3527 case Intrinsic::fabs:
3528 case Intrinsic::floor:
3529 case Intrinsic::ceil:
3530 case Intrinsic::trunc:
3531 case Intrinsic::rint:
3532 case Intrinsic::nearbyint:
3533 case Intrinsic::round:
3538 template <typename IterTy>
3539 static Value *SimplifyIntrinsic(Intrinsic::ID IID, IterTy ArgBegin, IterTy ArgEnd,
3540 const Query &Q, unsigned MaxRecurse) {
3541 // Perform idempotent optimizations
3542 if (!IsIdempotent(IID))
3546 if (std::distance(ArgBegin, ArgEnd) == 1)
3547 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(*ArgBegin))
3548 if (II->getIntrinsicID() == IID)
3554 template <typename IterTy>
3555 static Value *SimplifyCall(Value *V, IterTy ArgBegin, IterTy ArgEnd,
3556 const Query &Q, unsigned MaxRecurse) {
3557 Type *Ty = V->getType();
3558 if (PointerType *PTy = dyn_cast<PointerType>(Ty))
3559 Ty = PTy->getElementType();
3560 FunctionType *FTy = cast<FunctionType>(Ty);
3562 // call undef -> undef
3563 if (isa<UndefValue>(V))
3564 return UndefValue::get(FTy->getReturnType());
3566 Function *F = dyn_cast<Function>(V);
3570 if (unsigned IID = F->getIntrinsicID())
3572 SimplifyIntrinsic((Intrinsic::ID) IID, ArgBegin, ArgEnd, Q, MaxRecurse))
3575 if (!canConstantFoldCallTo(F))
3578 SmallVector<Constant *, 4> ConstantArgs;
3579 ConstantArgs.reserve(ArgEnd - ArgBegin);
3580 for (IterTy I = ArgBegin, E = ArgEnd; I != E; ++I) {
3581 Constant *C = dyn_cast<Constant>(*I);
3584 ConstantArgs.push_back(C);
3587 return ConstantFoldCall(F, ConstantArgs, Q.TLI);
3590 Value *llvm::SimplifyCall(Value *V, User::op_iterator ArgBegin,
3591 User::op_iterator ArgEnd, const DataLayout *DL,
3592 const TargetLibraryInfo *TLI, const DominatorTree *DT,
3593 AssumptionCache *AC, const Instruction *CxtI) {
3594 return ::SimplifyCall(V, ArgBegin, ArgEnd, Query(DL, TLI, DT, AC, CxtI),
3598 Value *llvm::SimplifyCall(Value *V, ArrayRef<Value *> Args,
3599 const DataLayout *DL, const TargetLibraryInfo *TLI,
3600 const DominatorTree *DT, AssumptionCache *AC,
3601 const Instruction *CxtI) {
3602 return ::SimplifyCall(V, Args.begin(), Args.end(),
3603 Query(DL, TLI, DT, AC, CxtI), RecursionLimit);
3606 /// SimplifyInstruction - See if we can compute a simplified version of this
3607 /// instruction. If not, this returns null.
3608 Value *llvm::SimplifyInstruction(Instruction *I, const DataLayout *DL,
3609 const TargetLibraryInfo *TLI,
3610 const DominatorTree *DT, AssumptionCache *AC) {
3613 switch (I->getOpcode()) {
3615 Result = ConstantFoldInstruction(I, DL, TLI);
3617 case Instruction::FAdd:
3618 Result = SimplifyFAddInst(I->getOperand(0), I->getOperand(1),
3619 I->getFastMathFlags(), DL, TLI, DT, AC, I);
3621 case Instruction::Add:
3622 Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
3623 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3624 cast<BinaryOperator>(I)->hasNoUnsignedWrap(), DL,
3627 case Instruction::FSub:
3628 Result = SimplifyFSubInst(I->getOperand(0), I->getOperand(1),
3629 I->getFastMathFlags(), DL, TLI, DT, AC, I);
3631 case Instruction::Sub:
3632 Result = SimplifySubInst(I->getOperand(0), I->getOperand(1),
3633 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3634 cast<BinaryOperator>(I)->hasNoUnsignedWrap(), DL,
3637 case Instruction::FMul:
3638 Result = SimplifyFMulInst(I->getOperand(0), I->getOperand(1),
3639 I->getFastMathFlags(), DL, TLI, DT, AC, I);
3641 case Instruction::Mul:
3643 SimplifyMulInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT, AC, I);
3645 case Instruction::SDiv:
3646 Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT,
3649 case Instruction::UDiv:
3650 Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT,
3653 case Instruction::FDiv:
3654 Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT,
3657 case Instruction::SRem:
3658 Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT,
3661 case Instruction::URem:
3662 Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT,
3665 case Instruction::FRem:
3666 Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT,
3669 case Instruction::Shl:
3670 Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1),
3671 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3672 cast<BinaryOperator>(I)->hasNoUnsignedWrap(), DL,
3675 case Instruction::LShr:
3676 Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
3677 cast<BinaryOperator>(I)->isExact(), DL, TLI, DT,
3680 case Instruction::AShr:
3681 Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
3682 cast<BinaryOperator>(I)->isExact(), DL, TLI, DT,
3685 case Instruction::And:
3687 SimplifyAndInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT, AC, I);
3689 case Instruction::Or:
3691 SimplifyOrInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT, AC, I);
3693 case Instruction::Xor:
3695 SimplifyXorInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT, AC, I);
3697 case Instruction::ICmp:
3699 SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(), I->getOperand(0),
3700 I->getOperand(1), DL, TLI, DT, AC, I);
3702 case Instruction::FCmp:
3704 SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(), I->getOperand(0),
3705 I->getOperand(1), DL, TLI, DT, AC, I);
3707 case Instruction::Select:
3708 Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
3709 I->getOperand(2), DL, TLI, DT, AC, I);
3711 case Instruction::GetElementPtr: {
3712 SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end());
3713 Result = SimplifyGEPInst(Ops, DL, TLI, DT, AC, I);
3716 case Instruction::InsertValue: {
3717 InsertValueInst *IV = cast<InsertValueInst>(I);
3718 Result = SimplifyInsertValueInst(IV->getAggregateOperand(),
3719 IV->getInsertedValueOperand(),
3720 IV->getIndices(), DL, TLI, DT, AC, I);
3723 case Instruction::PHI:
3724 Result = SimplifyPHINode(cast<PHINode>(I), Query(DL, TLI, DT, AC, I));
3726 case Instruction::Call: {
3727 CallSite CS(cast<CallInst>(I));
3728 Result = SimplifyCall(CS.getCalledValue(), CS.arg_begin(), CS.arg_end(), DL,
3732 case Instruction::Trunc:
3734 SimplifyTruncInst(I->getOperand(0), I->getType(), DL, TLI, DT, AC, I);
3738 /// If called on unreachable code, the above logic may report that the
3739 /// instruction simplified to itself. Make life easier for users by
3740 /// detecting that case here, returning a safe value instead.
3741 return Result == I ? UndefValue::get(I->getType()) : Result;
3744 /// \brief Implementation of recursive simplification through an instructions
3747 /// This is the common implementation of the recursive simplification routines.
3748 /// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
3749 /// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
3750 /// instructions to process and attempt to simplify it using
3751 /// InstructionSimplify.
3753 /// This routine returns 'true' only when *it* simplifies something. The passed
3754 /// in simplified value does not count toward this.
3755 static bool replaceAndRecursivelySimplifyImpl(Instruction *I, Value *SimpleV,
3756 const DataLayout *DL,
3757 const TargetLibraryInfo *TLI,
3758 const DominatorTree *DT,
3759 AssumptionCache *AC) {
3760 bool Simplified = false;
3761 SmallSetVector<Instruction *, 8> Worklist;
3763 // If we have an explicit value to collapse to, do that round of the
3764 // simplification loop by hand initially.
3766 for (User *U : I->users())
3768 Worklist.insert(cast<Instruction>(U));
3770 // Replace the instruction with its simplified value.
3771 I->replaceAllUsesWith(SimpleV);
3773 // Gracefully handle edge cases where the instruction is not wired into any
3776 I->eraseFromParent();
3781 // Note that we must test the size on each iteration, the worklist can grow.
3782 for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
3785 // See if this instruction simplifies.
3786 SimpleV = SimplifyInstruction(I, DL, TLI, DT, AC);
3792 // Stash away all the uses of the old instruction so we can check them for
3793 // recursive simplifications after a RAUW. This is cheaper than checking all
3794 // uses of To on the recursive step in most cases.
3795 for (User *U : I->users())
3796 Worklist.insert(cast<Instruction>(U));
3798 // Replace the instruction with its simplified value.
3799 I->replaceAllUsesWith(SimpleV);
3801 // Gracefully handle edge cases where the instruction is not wired into any
3804 I->eraseFromParent();
3809 bool llvm::recursivelySimplifyInstruction(Instruction *I, const DataLayout *DL,
3810 const TargetLibraryInfo *TLI,
3811 const DominatorTree *DT,
3812 AssumptionCache *AC) {
3813 return replaceAndRecursivelySimplifyImpl(I, nullptr, DL, TLI, DT, AC);
3816 bool llvm::replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV,
3817 const DataLayout *DL,
3818 const TargetLibraryInfo *TLI,
3819 const DominatorTree *DT,
3820 AssumptionCache *AC) {
3821 assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!");
3822 assert(SimpleV && "Must provide a simplified value.");
3823 return replaceAndRecursivelySimplifyImpl(I, SimpleV, DL, TLI, DT, AC);