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;
51 AssumptionTracker *AT;
52 const Instruction *CxtI;
54 Query(const DataLayout *DL, const TargetLibraryInfo *tli,
55 const DominatorTree *dt, AssumptionTracker *at = nullptr,
56 const Instruction *cxti = nullptr)
57 : DL(DL), TLI(tli), DT(dt), AT(at), 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 *SimplifyCmpInst(unsigned, Value *, Value *, const Query &,
66 static Value *SimplifyOrInst(Value *, Value *, const Query &, unsigned);
67 static Value *SimplifyXorInst(Value *, Value *, const Query &, unsigned);
68 static Value *SimplifyTruncInst(Value *, Type *, const Query &, unsigned);
70 /// getFalse - For a boolean type, or a vector of boolean type, return false, or
71 /// a vector with every element false, as appropriate for the type.
72 static Constant *getFalse(Type *Ty) {
73 assert(Ty->getScalarType()->isIntegerTy(1) &&
74 "Expected i1 type or a vector of i1!");
75 return Constant::getNullValue(Ty);
78 /// getTrue - For a boolean type, or a vector of boolean type, return true, or
79 /// a vector with every element true, as appropriate for the type.
80 static Constant *getTrue(Type *Ty) {
81 assert(Ty->getScalarType()->isIntegerTy(1) &&
82 "Expected i1 type or a vector of i1!");
83 return Constant::getAllOnesValue(Ty);
86 /// isSameCompare - Is V equivalent to the comparison "LHS Pred RHS"?
87 static bool isSameCompare(Value *V, CmpInst::Predicate Pred, Value *LHS,
89 CmpInst *Cmp = dyn_cast<CmpInst>(V);
92 CmpInst::Predicate CPred = Cmp->getPredicate();
93 Value *CLHS = Cmp->getOperand(0), *CRHS = Cmp->getOperand(1);
94 if (CPred == Pred && CLHS == LHS && CRHS == RHS)
96 return CPred == CmpInst::getSwappedPredicate(Pred) && CLHS == RHS &&
100 /// ValueDominatesPHI - Does the given value dominate the specified phi node?
101 static bool ValueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
102 Instruction *I = dyn_cast<Instruction>(V);
104 // Arguments and constants dominate all instructions.
107 // If we are processing instructions (and/or basic blocks) that have not been
108 // fully added to a function, the parent nodes may still be null. Simply
109 // return the conservative answer in these cases.
110 if (!I->getParent() || !P->getParent() || !I->getParent()->getParent())
113 // If we have a DominatorTree then do a precise test.
115 if (!DT->isReachableFromEntry(P->getParent()))
117 if (!DT->isReachableFromEntry(I->getParent()))
119 return DT->dominates(I, P);
122 // Otherwise, if the instruction is in the entry block, and is not an invoke,
123 // then it obviously dominates all phi nodes.
124 if (I->getParent() == &I->getParent()->getParent()->getEntryBlock() &&
131 /// ExpandBinOp - Simplify "A op (B op' C)" by distributing op over op', turning
132 /// it into "(A op B) op' (A op C)". Here "op" is given by Opcode and "op'" is
133 /// given by OpcodeToExpand, while "A" corresponds to LHS and "B op' C" to RHS.
134 /// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)".
135 /// Returns the simplified value, or null if no simplification was performed.
136 static Value *ExpandBinOp(unsigned Opcode, Value *LHS, Value *RHS,
137 unsigned OpcToExpand, const Query &Q,
138 unsigned MaxRecurse) {
139 Instruction::BinaryOps OpcodeToExpand = (Instruction::BinaryOps)OpcToExpand;
140 // Recursion is always used, so bail out at once if we already hit the limit.
144 // Check whether the expression has the form "(A op' B) op C".
145 if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS))
146 if (Op0->getOpcode() == OpcodeToExpand) {
147 // It does! Try turning it into "(A op C) op' (B op C)".
148 Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS;
149 // Do "A op C" and "B op C" both simplify?
150 if (Value *L = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse))
151 if (Value *R = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
152 // They do! Return "L op' R" if it simplifies or is already available.
153 // If "L op' R" equals "A op' B" then "L op' R" is just the LHS.
154 if ((L == A && R == B) || (Instruction::isCommutative(OpcodeToExpand)
155 && L == B && R == A)) {
159 // Otherwise return "L op' R" if it simplifies.
160 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
167 // Check whether the expression has the form "A op (B op' C)".
168 if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS))
169 if (Op1->getOpcode() == OpcodeToExpand) {
170 // It does! Try turning it into "(A op B) op' (A op C)".
171 Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1);
172 // Do "A op B" and "A op C" both simplify?
173 if (Value *L = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse))
174 if (Value *R = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse)) {
175 // They do! Return "L op' R" if it simplifies or is already available.
176 // If "L op' R" equals "B op' C" then "L op' R" is just the RHS.
177 if ((L == B && R == C) || (Instruction::isCommutative(OpcodeToExpand)
178 && L == C && R == B)) {
182 // Otherwise return "L op' R" if it simplifies.
183 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
193 /// SimplifyAssociativeBinOp - Generic simplifications for associative binary
194 /// operations. Returns the simpler value, or null if none was found.
195 static Value *SimplifyAssociativeBinOp(unsigned Opc, Value *LHS, Value *RHS,
196 const Query &Q, unsigned MaxRecurse) {
197 Instruction::BinaryOps Opcode = (Instruction::BinaryOps)Opc;
198 assert(Instruction::isAssociative(Opcode) && "Not an associative operation!");
200 // Recursion is always used, so bail out at once if we already hit the limit.
204 BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
205 BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
207 // Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely.
208 if (Op0 && Op0->getOpcode() == Opcode) {
209 Value *A = Op0->getOperand(0);
210 Value *B = Op0->getOperand(1);
213 // Does "B op C" simplify?
214 if (Value *V = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
215 // It does! Return "A op V" if it simplifies or is already available.
216 // If V equals B then "A op V" is just the LHS.
217 if (V == B) return LHS;
218 // Otherwise return "A op V" if it simplifies.
219 if (Value *W = SimplifyBinOp(Opcode, A, V, Q, MaxRecurse)) {
226 // Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely.
227 if (Op1 && Op1->getOpcode() == Opcode) {
229 Value *B = Op1->getOperand(0);
230 Value *C = Op1->getOperand(1);
232 // Does "A op B" simplify?
233 if (Value *V = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse)) {
234 // It does! Return "V op C" if it simplifies or is already available.
235 // If V equals B then "V op C" is just the RHS.
236 if (V == B) return RHS;
237 // Otherwise return "V op C" if it simplifies.
238 if (Value *W = SimplifyBinOp(Opcode, V, C, Q, MaxRecurse)) {
245 // The remaining transforms require commutativity as well as associativity.
246 if (!Instruction::isCommutative(Opcode))
249 // Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely.
250 if (Op0 && Op0->getOpcode() == Opcode) {
251 Value *A = Op0->getOperand(0);
252 Value *B = Op0->getOperand(1);
255 // Does "C op A" simplify?
256 if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
257 // It does! Return "V op B" if it simplifies or is already available.
258 // If V equals A then "V op B" is just the LHS.
259 if (V == A) return LHS;
260 // Otherwise return "V op B" if it simplifies.
261 if (Value *W = SimplifyBinOp(Opcode, V, B, Q, MaxRecurse)) {
268 // Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely.
269 if (Op1 && Op1->getOpcode() == Opcode) {
271 Value *B = Op1->getOperand(0);
272 Value *C = Op1->getOperand(1);
274 // Does "C op A" simplify?
275 if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
276 // It does! Return "B op V" if it simplifies or is already available.
277 // If V equals C then "B op V" is just the RHS.
278 if (V == C) return RHS;
279 // Otherwise return "B op V" if it simplifies.
280 if (Value *W = SimplifyBinOp(Opcode, B, V, Q, MaxRecurse)) {
290 /// ThreadBinOpOverSelect - In the case of a binary operation with a select
291 /// instruction as an operand, try to simplify the binop by seeing whether
292 /// evaluating it on both branches of the select results in the same value.
293 /// Returns the common value if so, otherwise returns null.
294 static Value *ThreadBinOpOverSelect(unsigned Opcode, Value *LHS, Value *RHS,
295 const Query &Q, unsigned MaxRecurse) {
296 // Recursion is always used, so bail out at once if we already hit the limit.
301 if (isa<SelectInst>(LHS)) {
302 SI = cast<SelectInst>(LHS);
304 assert(isa<SelectInst>(RHS) && "No select instruction operand!");
305 SI = cast<SelectInst>(RHS);
308 // Evaluate the BinOp on the true and false branches of the select.
312 TV = SimplifyBinOp(Opcode, SI->getTrueValue(), RHS, Q, MaxRecurse);
313 FV = SimplifyBinOp(Opcode, SI->getFalseValue(), RHS, Q, MaxRecurse);
315 TV = SimplifyBinOp(Opcode, LHS, SI->getTrueValue(), Q, MaxRecurse);
316 FV = SimplifyBinOp(Opcode, LHS, SI->getFalseValue(), Q, MaxRecurse);
319 // If they simplified to the same value, then return the common value.
320 // If they both failed to simplify then return null.
324 // If one branch simplified to undef, return the other one.
325 if (TV && isa<UndefValue>(TV))
327 if (FV && isa<UndefValue>(FV))
330 // If applying the operation did not change the true and false select values,
331 // then the result of the binop is the select itself.
332 if (TV == SI->getTrueValue() && FV == SI->getFalseValue())
335 // If one branch simplified and the other did not, and the simplified
336 // value is equal to the unsimplified one, return the simplified value.
337 // For example, select (cond, X, X & Z) & Z -> X & Z.
338 if ((FV && !TV) || (TV && !FV)) {
339 // Check that the simplified value has the form "X op Y" where "op" is the
340 // same as the original operation.
341 Instruction *Simplified = dyn_cast<Instruction>(FV ? FV : TV);
342 if (Simplified && Simplified->getOpcode() == Opcode) {
343 // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS".
344 // We already know that "op" is the same as for the simplified value. See
345 // if the operands match too. If so, return the simplified value.
346 Value *UnsimplifiedBranch = FV ? SI->getTrueValue() : SI->getFalseValue();
347 Value *UnsimplifiedLHS = SI == LHS ? UnsimplifiedBranch : LHS;
348 Value *UnsimplifiedRHS = SI == LHS ? RHS : UnsimplifiedBranch;
349 if (Simplified->getOperand(0) == UnsimplifiedLHS &&
350 Simplified->getOperand(1) == UnsimplifiedRHS)
352 if (Simplified->isCommutative() &&
353 Simplified->getOperand(1) == UnsimplifiedLHS &&
354 Simplified->getOperand(0) == UnsimplifiedRHS)
362 /// ThreadCmpOverSelect - In the case of a comparison with a select instruction,
363 /// try to simplify the comparison by seeing whether both branches of the select
364 /// result in the same value. Returns the common value if so, otherwise returns
366 static Value *ThreadCmpOverSelect(CmpInst::Predicate Pred, Value *LHS,
367 Value *RHS, const Query &Q,
368 unsigned MaxRecurse) {
369 // Recursion is always used, so bail out at once if we already hit the limit.
373 // Make sure the select is on the LHS.
374 if (!isa<SelectInst>(LHS)) {
376 Pred = CmpInst::getSwappedPredicate(Pred);
378 assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!");
379 SelectInst *SI = cast<SelectInst>(LHS);
380 Value *Cond = SI->getCondition();
381 Value *TV = SI->getTrueValue();
382 Value *FV = SI->getFalseValue();
384 // Now that we have "cmp select(Cond, TV, FV), RHS", analyse it.
385 // Does "cmp TV, RHS" simplify?
386 Value *TCmp = SimplifyCmpInst(Pred, TV, RHS, Q, MaxRecurse);
388 // It not only simplified, it simplified to the select condition. Replace
390 TCmp = getTrue(Cond->getType());
392 // It didn't simplify. However if "cmp TV, RHS" is equal to the select
393 // condition then we can replace it with 'true'. Otherwise give up.
394 if (!isSameCompare(Cond, Pred, TV, RHS))
396 TCmp = getTrue(Cond->getType());
399 // Does "cmp FV, RHS" simplify?
400 Value *FCmp = SimplifyCmpInst(Pred, FV, RHS, Q, MaxRecurse);
402 // It not only simplified, it simplified to the select condition. Replace
404 FCmp = getFalse(Cond->getType());
406 // It didn't simplify. However if "cmp FV, RHS" is equal to the select
407 // condition then we can replace it with 'false'. Otherwise give up.
408 if (!isSameCompare(Cond, Pred, FV, RHS))
410 FCmp = getFalse(Cond->getType());
413 // If both sides simplified to the same value, then use it as the result of
414 // the original comparison.
418 // The remaining cases only make sense if the select condition has the same
419 // type as the result of the comparison, so bail out if this is not so.
420 if (Cond->getType()->isVectorTy() != RHS->getType()->isVectorTy())
422 // If the false value simplified to false, then the result of the compare
423 // is equal to "Cond && TCmp". This also catches the case when the false
424 // value simplified to false and the true value to true, returning "Cond".
425 if (match(FCmp, m_Zero()))
426 if (Value *V = SimplifyAndInst(Cond, TCmp, Q, MaxRecurse))
428 // If the true value simplified to true, then the result of the compare
429 // is equal to "Cond || FCmp".
430 if (match(TCmp, m_One()))
431 if (Value *V = SimplifyOrInst(Cond, FCmp, Q, MaxRecurse))
433 // Finally, if the false value simplified to true and the true value to
434 // false, then the result of the compare is equal to "!Cond".
435 if (match(FCmp, m_One()) && match(TCmp, m_Zero()))
437 SimplifyXorInst(Cond, Constant::getAllOnesValue(Cond->getType()),
444 /// ThreadBinOpOverPHI - In the case of a binary operation with an operand that
445 /// is a PHI instruction, try to simplify the binop by seeing whether evaluating
446 /// it on the incoming phi values yields the same result for every value. If so
447 /// returns the common value, otherwise returns null.
448 static Value *ThreadBinOpOverPHI(unsigned Opcode, Value *LHS, Value *RHS,
449 const Query &Q, unsigned MaxRecurse) {
450 // Recursion is always used, so bail out at once if we already hit the limit.
455 if (isa<PHINode>(LHS)) {
456 PI = cast<PHINode>(LHS);
457 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
458 if (!ValueDominatesPHI(RHS, PI, Q.DT))
461 assert(isa<PHINode>(RHS) && "No PHI instruction operand!");
462 PI = cast<PHINode>(RHS);
463 // Bail out if LHS and the phi may be mutually interdependent due to a loop.
464 if (!ValueDominatesPHI(LHS, PI, Q.DT))
468 // Evaluate the BinOp on the incoming phi values.
469 Value *CommonValue = nullptr;
470 for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
471 Value *Incoming = PI->getIncomingValue(i);
472 // If the incoming value is the phi node itself, it can safely be skipped.
473 if (Incoming == PI) continue;
474 Value *V = PI == LHS ?
475 SimplifyBinOp(Opcode, Incoming, RHS, Q, MaxRecurse) :
476 SimplifyBinOp(Opcode, LHS, Incoming, Q, MaxRecurse);
477 // If the operation failed to simplify, or simplified to a different value
478 // to previously, then give up.
479 if (!V || (CommonValue && V != CommonValue))
487 /// ThreadCmpOverPHI - In the case of a comparison with a PHI instruction, try
488 /// try to simplify the comparison by seeing whether comparing with all of the
489 /// incoming phi values yields the same result every time. If so returns the
490 /// common result, otherwise returns null.
491 static Value *ThreadCmpOverPHI(CmpInst::Predicate Pred, Value *LHS, Value *RHS,
492 const Query &Q, unsigned MaxRecurse) {
493 // Recursion is always used, so bail out at once if we already hit the limit.
497 // Make sure the phi is on the LHS.
498 if (!isa<PHINode>(LHS)) {
500 Pred = CmpInst::getSwappedPredicate(Pred);
502 assert(isa<PHINode>(LHS) && "Not comparing with a phi instruction!");
503 PHINode *PI = cast<PHINode>(LHS);
505 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
506 if (!ValueDominatesPHI(RHS, PI, Q.DT))
509 // Evaluate the BinOp on the incoming phi values.
510 Value *CommonValue = nullptr;
511 for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
512 Value *Incoming = PI->getIncomingValue(i);
513 // If the incoming value is the phi node itself, it can safely be skipped.
514 if (Incoming == PI) continue;
515 Value *V = SimplifyCmpInst(Pred, Incoming, RHS, Q, MaxRecurse);
516 // If the operation failed to simplify, or simplified to a different value
517 // to previously, then give up.
518 if (!V || (CommonValue && V != CommonValue))
526 /// SimplifyAddInst - Given operands for an Add, see if we can
527 /// fold the result. If not, this returns null.
528 static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
529 const Query &Q, unsigned MaxRecurse) {
530 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
531 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
532 Constant *Ops[] = { CLHS, CRHS };
533 return ConstantFoldInstOperands(Instruction::Add, CLHS->getType(), Ops,
537 // Canonicalize the constant to the RHS.
541 // X + undef -> undef
542 if (match(Op1, m_Undef()))
546 if (match(Op1, m_Zero()))
553 if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) ||
554 match(Op0, m_Sub(m_Value(Y), m_Specific(Op1))))
557 // X + ~X -> -1 since ~X = -X-1
558 if (match(Op0, m_Not(m_Specific(Op1))) ||
559 match(Op1, m_Not(m_Specific(Op0))))
560 return Constant::getAllOnesValue(Op0->getType());
563 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
564 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
567 // Try some generic simplifications for associative operations.
568 if (Value *V = SimplifyAssociativeBinOp(Instruction::Add, Op0, Op1, Q,
572 // Threading Add over selects and phi nodes is pointless, so don't bother.
573 // Threading over the select in "A + select(cond, B, C)" means evaluating
574 // "A+B" and "A+C" and seeing if they are equal; but they are equal if and
575 // only if B and C are equal. If B and C are equal then (since we assume
576 // that operands have already been simplified) "select(cond, B, C)" should
577 // have been simplified to the common value of B and C already. Analysing
578 // "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly
579 // for threading over phi nodes.
584 Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
585 const DataLayout *DL, const TargetLibraryInfo *TLI,
586 const DominatorTree *DT, AssumptionTracker *AT,
587 const Instruction *CxtI) {
588 return ::SimplifyAddInst(Op0, Op1, isNSW, isNUW,
589 Query (DL, TLI, DT, AT, CxtI), RecursionLimit);
592 /// \brief Compute the base pointer and cumulative constant offsets for V.
594 /// This strips all constant offsets off of V, leaving it the base pointer, and
595 /// accumulates the total constant offset applied in the returned constant. It
596 /// returns 0 if V is not a pointer, and returns the constant '0' if there are
597 /// no constant offsets applied.
599 /// This is very similar to GetPointerBaseWithConstantOffset except it doesn't
600 /// follow non-inbounds geps. This allows it to remain usable for icmp ult/etc.
602 static Constant *stripAndComputeConstantOffsets(const DataLayout *DL,
604 bool AllowNonInbounds = false) {
605 assert(V->getType()->getScalarType()->isPointerTy());
607 // Without DataLayout, just be conservative for now. Theoretically, more could
608 // be done in this case.
610 return ConstantInt::get(IntegerType::get(V->getContext(), 64), 0);
612 Type *IntPtrTy = DL->getIntPtrType(V->getType())->getScalarType();
613 APInt Offset = APInt::getNullValue(IntPtrTy->getIntegerBitWidth());
615 // Even though we don't look through PHI nodes, we could be called on an
616 // instruction in an unreachable block, which may be on a cycle.
617 SmallPtrSet<Value *, 4> Visited;
620 if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
621 if ((!AllowNonInbounds && !GEP->isInBounds()) ||
622 !GEP->accumulateConstantOffset(*DL, Offset))
624 V = GEP->getPointerOperand();
625 } else if (Operator::getOpcode(V) == Instruction::BitCast) {
626 V = cast<Operator>(V)->getOperand(0);
627 } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
628 if (GA->mayBeOverridden())
630 V = GA->getAliasee();
634 assert(V->getType()->getScalarType()->isPointerTy() &&
635 "Unexpected operand type!");
636 } while (Visited.insert(V).second);
638 Constant *OffsetIntPtr = ConstantInt::get(IntPtrTy, Offset);
639 if (V->getType()->isVectorTy())
640 return ConstantVector::getSplat(V->getType()->getVectorNumElements(),
645 /// \brief Compute the constant difference between two pointer values.
646 /// If the difference is not a constant, returns zero.
647 static Constant *computePointerDifference(const DataLayout *DL,
648 Value *LHS, Value *RHS) {
649 Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
650 Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
652 // If LHS and RHS are not related via constant offsets to the same base
653 // value, there is nothing we can do here.
657 // Otherwise, the difference of LHS - RHS can be computed as:
659 // = (LHSOffset + Base) - (RHSOffset + Base)
660 // = LHSOffset - RHSOffset
661 return ConstantExpr::getSub(LHSOffset, RHSOffset);
664 /// SimplifySubInst - Given operands for a Sub, see if we can
665 /// fold the result. If not, this returns null.
666 static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
667 const Query &Q, unsigned MaxRecurse) {
668 if (Constant *CLHS = dyn_cast<Constant>(Op0))
669 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
670 Constant *Ops[] = { CLHS, CRHS };
671 return ConstantFoldInstOperands(Instruction::Sub, CLHS->getType(),
675 // X - undef -> undef
676 // undef - X -> undef
677 if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
678 return UndefValue::get(Op0->getType());
681 if (match(Op1, m_Zero()))
686 return Constant::getNullValue(Op0->getType());
688 // 0 - X -> 0 if the sub is NUW.
689 if (isNUW && match(Op0, m_Zero()))
692 // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
693 // For example, (X + Y) - Y -> X; (Y + X) - Y -> X
694 Value *X = nullptr, *Y = nullptr, *Z = Op1;
695 if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z
696 // See if "V === Y - Z" simplifies.
697 if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, Q, MaxRecurse-1))
698 // It does! Now see if "X + V" simplifies.
699 if (Value *W = SimplifyBinOp(Instruction::Add, X, V, Q, MaxRecurse-1)) {
700 // It does, we successfully reassociated!
704 // See if "V === X - Z" simplifies.
705 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
706 // It does! Now see if "Y + V" simplifies.
707 if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, Q, MaxRecurse-1)) {
708 // It does, we successfully reassociated!
714 // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
715 // For example, X - (X + 1) -> -1
717 if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z)
718 // See if "V === X - Y" simplifies.
719 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
720 // It does! Now see if "V - Z" simplifies.
721 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, Q, MaxRecurse-1)) {
722 // It does, we successfully reassociated!
726 // See if "V === X - Z" simplifies.
727 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
728 // It does! Now see if "V - Y" simplifies.
729 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, Q, MaxRecurse-1)) {
730 // It does, we successfully reassociated!
736 // Z - (X - Y) -> (Z - X) + Y if everything simplifies.
737 // For example, X - (X - Y) -> Y.
739 if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y)
740 // See if "V === Z - X" simplifies.
741 if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, Q, MaxRecurse-1))
742 // It does! Now see if "V + Y" simplifies.
743 if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, Q, MaxRecurse-1)) {
744 // It does, we successfully reassociated!
749 // trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies.
750 if (MaxRecurse && match(Op0, m_Trunc(m_Value(X))) &&
751 match(Op1, m_Trunc(m_Value(Y))))
752 if (X->getType() == Y->getType())
753 // See if "V === X - Y" simplifies.
754 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
755 // It does! Now see if "trunc V" simplifies.
756 if (Value *W = SimplifyTruncInst(V, Op0->getType(), Q, MaxRecurse-1))
757 // It does, return the simplified "trunc V".
760 // Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...).
761 if (match(Op0, m_PtrToInt(m_Value(X))) &&
762 match(Op1, m_PtrToInt(m_Value(Y))))
763 if (Constant *Result = computePointerDifference(Q.DL, X, Y))
764 return ConstantExpr::getIntegerCast(Result, Op0->getType(), true);
767 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
768 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
771 // Threading Sub over selects and phi nodes is pointless, so don't bother.
772 // Threading over the select in "A - select(cond, B, C)" means evaluating
773 // "A-B" and "A-C" and seeing if they are equal; but they are equal if and
774 // only if B and C are equal. If B and C are equal then (since we assume
775 // that operands have already been simplified) "select(cond, B, C)" should
776 // have been simplified to the common value of B and C already. Analysing
777 // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly
778 // for threading over phi nodes.
783 Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
784 const DataLayout *DL, const TargetLibraryInfo *TLI,
785 const DominatorTree *DT, AssumptionTracker *AT,
786 const Instruction *CxtI) {
787 return ::SimplifySubInst(Op0, Op1, isNSW, isNUW,
788 Query (DL, TLI, DT, AT, CxtI), RecursionLimit);
791 /// Given operands for an FAdd, see if we can fold the result. If not, this
793 static Value *SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
794 const Query &Q, unsigned MaxRecurse) {
795 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
796 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
797 Constant *Ops[] = { CLHS, CRHS };
798 return ConstantFoldInstOperands(Instruction::FAdd, CLHS->getType(),
802 // Canonicalize the constant to the RHS.
807 if (match(Op1, m_NegZero()))
810 // fadd X, 0 ==> X, when we know X is not -0
811 if (match(Op1, m_Zero()) &&
812 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
815 // fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
816 // where nnan and ninf have to occur at least once somewhere in this
818 Value *SubOp = nullptr;
819 if (match(Op1, m_FSub(m_AnyZero(), m_Specific(Op0))))
821 else if (match(Op0, m_FSub(m_AnyZero(), m_Specific(Op1))))
824 Instruction *FSub = cast<Instruction>(SubOp);
825 if ((FMF.noNaNs() || FSub->hasNoNaNs()) &&
826 (FMF.noInfs() || FSub->hasNoInfs()))
827 return Constant::getNullValue(Op0->getType());
833 /// Given operands for an FSub, see if we can fold the result. If not, this
835 static Value *SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
836 const Query &Q, unsigned MaxRecurse) {
837 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
838 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
839 Constant *Ops[] = { CLHS, CRHS };
840 return ConstantFoldInstOperands(Instruction::FSub, CLHS->getType(),
846 if (match(Op1, m_Zero()))
849 // fsub X, -0 ==> X, when we know X is not -0
850 if (match(Op1, m_NegZero()) &&
851 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
854 // fsub 0, (fsub -0.0, X) ==> X
856 if (match(Op0, m_AnyZero())) {
857 if (match(Op1, m_FSub(m_NegZero(), m_Value(X))))
859 if (FMF.noSignedZeros() && match(Op1, m_FSub(m_AnyZero(), m_Value(X))))
863 // fsub nnan ninf x, x ==> 0.0
864 if (FMF.noNaNs() && FMF.noInfs() && Op0 == Op1)
865 return Constant::getNullValue(Op0->getType());
870 /// Given the operands for an FMul, see if we can fold the result
871 static Value *SimplifyFMulInst(Value *Op0, Value *Op1,
874 unsigned MaxRecurse) {
875 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
876 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
877 Constant *Ops[] = { CLHS, CRHS };
878 return ConstantFoldInstOperands(Instruction::FMul, CLHS->getType(),
882 // Canonicalize the constant to the RHS.
887 if (match(Op1, m_FPOne()))
890 // fmul nnan nsz X, 0 ==> 0
891 if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZero()))
897 /// SimplifyMulInst - Given operands for a Mul, see if we can
898 /// fold the result. If not, this returns null.
899 static Value *SimplifyMulInst(Value *Op0, Value *Op1, const Query &Q,
900 unsigned MaxRecurse) {
901 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
902 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
903 Constant *Ops[] = { CLHS, CRHS };
904 return ConstantFoldInstOperands(Instruction::Mul, CLHS->getType(),
908 // Canonicalize the constant to the RHS.
913 if (match(Op1, m_Undef()))
914 return Constant::getNullValue(Op0->getType());
917 if (match(Op1, m_Zero()))
921 if (match(Op1, m_One()))
924 // (X / Y) * Y -> X if the division is exact.
926 if (match(Op0, m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y
927 match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0))))) // Y * (X / Y)
931 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
932 if (Value *V = SimplifyAndInst(Op0, Op1, Q, MaxRecurse-1))
935 // Try some generic simplifications for associative operations.
936 if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, Q,
940 // Mul distributes over Add. Try some generic simplifications based on this.
941 if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add,
945 // If the operation is with the result of a select instruction, check whether
946 // operating on either branch of the select always yields the same value.
947 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
948 if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, Q,
952 // If the operation is with the result of a phi instruction, check whether
953 // operating on all incoming values of the phi always yields the same value.
954 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
955 if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, Q,
962 Value *llvm::SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
963 const DataLayout *DL, const TargetLibraryInfo *TLI,
964 const DominatorTree *DT, AssumptionTracker *AT,
965 const Instruction *CxtI) {
966 return ::SimplifyFAddInst(Op0, Op1, FMF, Query (DL, TLI, DT, AT, CxtI),
970 Value *llvm::SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
971 const DataLayout *DL, const TargetLibraryInfo *TLI,
972 const DominatorTree *DT, AssumptionTracker *AT,
973 const Instruction *CxtI) {
974 return ::SimplifyFSubInst(Op0, Op1, FMF, Query (DL, TLI, DT, AT, CxtI),
978 Value *llvm::SimplifyFMulInst(Value *Op0, Value *Op1,
980 const DataLayout *DL,
981 const TargetLibraryInfo *TLI,
982 const DominatorTree *DT,
983 AssumptionTracker *AT,
984 const Instruction *CxtI) {
985 return ::SimplifyFMulInst(Op0, Op1, FMF, Query (DL, TLI, DT, AT, CxtI),
989 Value *llvm::SimplifyMulInst(Value *Op0, Value *Op1, const DataLayout *DL,
990 const TargetLibraryInfo *TLI,
991 const DominatorTree *DT, AssumptionTracker *AT,
992 const Instruction *CxtI) {
993 return ::SimplifyMulInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
997 /// SimplifyDiv - Given operands for an SDiv or UDiv, see if we can
998 /// fold the result. If not, this returns null.
999 static Value *SimplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
1000 const Query &Q, unsigned MaxRecurse) {
1001 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1002 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1003 Constant *Ops[] = { C0, C1 };
1004 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.DL, Q.TLI);
1008 bool isSigned = Opcode == Instruction::SDiv;
1010 // X / undef -> undef
1011 if (match(Op1, m_Undef()))
1014 // X / 0 -> undef, we don't need to preserve faults!
1015 if (match(Op1, m_Zero()))
1016 return UndefValue::get(Op1->getType());
1019 if (match(Op0, m_Undef()))
1020 return Constant::getNullValue(Op0->getType());
1022 // 0 / X -> 0, we don't need to preserve faults!
1023 if (match(Op0, m_Zero()))
1027 if (match(Op1, m_One()))
1030 if (Op0->getType()->isIntegerTy(1))
1031 // It can't be division by zero, hence it must be division by one.
1036 return ConstantInt::get(Op0->getType(), 1);
1038 // (X * Y) / Y -> X if the multiplication does not overflow.
1039 Value *X = nullptr, *Y = nullptr;
1040 if (match(Op0, m_Mul(m_Value(X), m_Value(Y))) && (X == Op1 || Y == Op1)) {
1041 if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1
1042 OverflowingBinaryOperator *Mul = cast<OverflowingBinaryOperator>(Op0);
1043 // If the Mul knows it does not overflow, then we are good to go.
1044 if ((isSigned && Mul->hasNoSignedWrap()) ||
1045 (!isSigned && Mul->hasNoUnsignedWrap()))
1047 // If X has the form X = A / Y then X * Y cannot overflow.
1048 if (BinaryOperator *Div = dyn_cast<BinaryOperator>(X))
1049 if (Div->getOpcode() == Opcode && Div->getOperand(1) == Y)
1053 // (X rem Y) / Y -> 0
1054 if ((isSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1055 (!isSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1056 return Constant::getNullValue(Op0->getType());
1058 // (X /u C1) /u C2 -> 0 if C1 * C2 overflow
1059 ConstantInt *C1, *C2;
1060 if (!isSigned && match(Op0, m_UDiv(m_Value(X), m_ConstantInt(C1))) &&
1061 match(Op1, m_ConstantInt(C2))) {
1063 C1->getValue().umul_ov(C2->getValue(), Overflow);
1065 return Constant::getNullValue(Op0->getType());
1068 // If the operation is with the result of a select instruction, check whether
1069 // operating on either branch of the select always yields the same value.
1070 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1071 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1074 // If the operation is with the result of a phi instruction, check whether
1075 // operating on all incoming values of the phi always yields the same value.
1076 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1077 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1083 /// SimplifySDivInst - Given operands for an SDiv, see if we can
1084 /// fold the result. If not, this returns null.
1085 static Value *SimplifySDivInst(Value *Op0, Value *Op1, const Query &Q,
1086 unsigned MaxRecurse) {
1087 if (Value *V = SimplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse))
1093 Value *llvm::SimplifySDivInst(Value *Op0, Value *Op1, const DataLayout *DL,
1094 const TargetLibraryInfo *TLI,
1095 const DominatorTree *DT,
1096 AssumptionTracker *AT,
1097 const Instruction *CxtI) {
1098 return ::SimplifySDivInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1102 /// SimplifyUDivInst - Given operands for a UDiv, see if we can
1103 /// fold the result. If not, this returns null.
1104 static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const Query &Q,
1105 unsigned MaxRecurse) {
1106 if (Value *V = SimplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse))
1112 Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const DataLayout *DL,
1113 const TargetLibraryInfo *TLI,
1114 const DominatorTree *DT,
1115 AssumptionTracker *AT,
1116 const Instruction *CxtI) {
1117 return ::SimplifyUDivInst(Op0, Op1, Query (DL, TLI, DT, AT, 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,
1137 AssumptionTracker *AT,
1138 const Instruction *CxtI) {
1139 return ::SimplifyFDivInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1143 /// SimplifyRem - Given operands for an SRem or URem, see if we can
1144 /// fold the result. If not, this returns null.
1145 static Value *SimplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
1146 const Query &Q, unsigned MaxRecurse) {
1147 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1148 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1149 Constant *Ops[] = { C0, C1 };
1150 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.DL, Q.TLI);
1154 // X % undef -> undef
1155 if (match(Op1, m_Undef()))
1159 if (match(Op0, m_Undef()))
1160 return Constant::getNullValue(Op0->getType());
1162 // 0 % X -> 0, we don't need to preserve faults!
1163 if (match(Op0, m_Zero()))
1166 // X % 0 -> undef, we don't need to preserve faults!
1167 if (match(Op1, m_Zero()))
1168 return UndefValue::get(Op0->getType());
1171 if (match(Op1, m_One()))
1172 return Constant::getNullValue(Op0->getType());
1174 if (Op0->getType()->isIntegerTy(1))
1175 // It can't be remainder by zero, hence it must be remainder by one.
1176 return Constant::getNullValue(Op0->getType());
1180 return Constant::getNullValue(Op0->getType());
1182 // (X % Y) % Y -> X % Y
1183 if ((Opcode == Instruction::SRem &&
1184 match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1185 (Opcode == Instruction::URem &&
1186 match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1189 // If the operation is with the result of a select instruction, check whether
1190 // operating on either branch of the select always yields the same value.
1191 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1192 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1195 // If the operation is with the result of a phi instruction, check whether
1196 // operating on all incoming values of the phi always yields the same value.
1197 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1198 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1204 /// SimplifySRemInst - Given operands for an SRem, see if we can
1205 /// fold the result. If not, this returns null.
1206 static Value *SimplifySRemInst(Value *Op0, Value *Op1, const Query &Q,
1207 unsigned MaxRecurse) {
1208 if (Value *V = SimplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse))
1214 Value *llvm::SimplifySRemInst(Value *Op0, Value *Op1, const DataLayout *DL,
1215 const TargetLibraryInfo *TLI,
1216 const DominatorTree *DT,
1217 AssumptionTracker *AT,
1218 const Instruction *CxtI) {
1219 return ::SimplifySRemInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1223 /// SimplifyURemInst - Given operands for a URem, see if we can
1224 /// fold the result. If not, this returns null.
1225 static Value *SimplifyURemInst(Value *Op0, Value *Op1, const Query &Q,
1226 unsigned MaxRecurse) {
1227 if (Value *V = SimplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse))
1233 Value *llvm::SimplifyURemInst(Value *Op0, Value *Op1, const DataLayout *DL,
1234 const TargetLibraryInfo *TLI,
1235 const DominatorTree *DT,
1236 AssumptionTracker *AT,
1237 const Instruction *CxtI) {
1238 return ::SimplifyURemInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1242 static Value *SimplifyFRemInst(Value *Op0, Value *Op1, const Query &,
1244 // undef % X -> undef (the undef could be a snan).
1245 if (match(Op0, m_Undef()))
1248 // X % undef -> undef
1249 if (match(Op1, m_Undef()))
1255 Value *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, const DataLayout *DL,
1256 const TargetLibraryInfo *TLI,
1257 const DominatorTree *DT,
1258 AssumptionTracker *AT,
1259 const Instruction *CxtI) {
1260 return ::SimplifyFRemInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1264 /// isUndefShift - Returns true if a shift by \c Amount always yields undef.
1265 static bool isUndefShift(Value *Amount) {
1266 Constant *C = dyn_cast<Constant>(Amount);
1270 // X shift by undef -> undef because it may shift by the bitwidth.
1271 if (isa<UndefValue>(C))
1274 // Shifting by the bitwidth or more is undefined.
1275 if (ConstantInt *CI = dyn_cast<ConstantInt>(C))
1276 if (CI->getValue().getLimitedValue() >=
1277 CI->getType()->getScalarSizeInBits())
1280 // If all lanes of a vector shift are undefined the whole shift is.
1281 if (isa<ConstantVector>(C) || isa<ConstantDataVector>(C)) {
1282 for (unsigned I = 0, E = C->getType()->getVectorNumElements(); I != E; ++I)
1283 if (!isUndefShift(C->getAggregateElement(I)))
1291 /// SimplifyShift - Given operands for an Shl, LShr or AShr, see if we can
1292 /// fold the result. If not, this returns null.
1293 static Value *SimplifyShift(unsigned Opcode, Value *Op0, Value *Op1,
1294 const Query &Q, unsigned MaxRecurse) {
1295 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1296 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1297 Constant *Ops[] = { C0, C1 };
1298 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.DL, Q.TLI);
1302 // 0 shift by X -> 0
1303 if (match(Op0, m_Zero()))
1306 // X shift by 0 -> X
1307 if (match(Op1, m_Zero()))
1310 // Fold undefined shifts.
1311 if (isUndefShift(Op1))
1312 return UndefValue::get(Op0->getType());
1314 // If the operation is with the result of a select instruction, check whether
1315 // operating on either branch of the select always yields the same value.
1316 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1317 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1320 // If the operation is with the result of a phi instruction, check whether
1321 // operating on all incoming values of the phi always yields the same value.
1322 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1323 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1329 /// \brief Given operands for an Shl, LShr or AShr, see if we can
1330 /// fold the result. If not, this returns null.
1331 static Value *SimplifyRightShift(unsigned Opcode, Value *Op0, Value *Op1,
1332 bool isExact, const Query &Q,
1333 unsigned MaxRecurse) {
1334 if (Value *V = SimplifyShift(Opcode, Op0, Op1, Q, MaxRecurse))
1339 return Constant::getNullValue(Op0->getType());
1342 // undef >> X -> undef (if it's exact)
1343 if (match(Op0, m_Undef()))
1344 return isExact ? Op0 : Constant::getNullValue(Op0->getType());
1346 // The low bit cannot be shifted out of an exact shift if it is set.
1348 unsigned BitWidth = Op0->getType()->getScalarSizeInBits();
1349 APInt Op0KnownZero(BitWidth, 0);
1350 APInt Op0KnownOne(BitWidth, 0);
1351 computeKnownBits(Op0, Op0KnownZero, Op0KnownOne, Q.DL, /*Depth=*/0, Q.AT, Q.CxtI,
1360 /// SimplifyShlInst - Given operands for an Shl, see if we can
1361 /// fold the result. If not, this returns null.
1362 static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1363 const Query &Q, unsigned MaxRecurse) {
1364 if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse))
1368 // undef << X -> undef if (if it's NSW/NUW)
1369 if (match(Op0, m_Undef()))
1370 return isNSW || isNUW ? Op0 : Constant::getNullValue(Op0->getType());
1372 // (X >> A) << A -> X
1374 if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
1379 Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1380 const DataLayout *DL, const TargetLibraryInfo *TLI,
1381 const DominatorTree *DT, AssumptionTracker *AT,
1382 const Instruction *CxtI) {
1383 return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Query (DL, TLI, DT, AT, CxtI),
1387 /// SimplifyLShrInst - Given operands for an LShr, see if we can
1388 /// fold the result. If not, this returns null.
1389 static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1390 const Query &Q, unsigned MaxRecurse) {
1391 if (Value *V = SimplifyRightShift(Instruction::LShr, Op0, Op1, isExact, Q,
1395 // (X << A) >> A -> X
1397 if (match(Op0, m_NUWShl(m_Value(X), m_Specific(Op1))))
1403 Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1404 const DataLayout *DL,
1405 const TargetLibraryInfo *TLI,
1406 const DominatorTree *DT,
1407 AssumptionTracker *AT,
1408 const Instruction *CxtI) {
1409 return ::SimplifyLShrInst(Op0, Op1, isExact, Query (DL, TLI, DT, AT, CxtI),
1413 /// SimplifyAShrInst - Given operands for an AShr, see if we can
1414 /// fold the result. If not, this returns null.
1415 static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1416 const Query &Q, unsigned MaxRecurse) {
1417 if (Value *V = SimplifyRightShift(Instruction::AShr, Op0, Op1, isExact, Q,
1421 // all ones >>a X -> all ones
1422 if (match(Op0, m_AllOnes()))
1425 // (X << A) >> A -> X
1427 if (match(Op0, m_NSWShl(m_Value(X), m_Specific(Op1))))
1430 // Arithmetic shifting an all-sign-bit value is a no-op.
1431 unsigned NumSignBits = ComputeNumSignBits(Op0, Q.DL, 0, Q.AT, Q.CxtI, Q.DT);
1432 if (NumSignBits == Op0->getType()->getScalarSizeInBits())
1438 Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1439 const DataLayout *DL,
1440 const TargetLibraryInfo *TLI,
1441 const DominatorTree *DT,
1442 AssumptionTracker *AT,
1443 const Instruction *CxtI) {
1444 return ::SimplifyAShrInst(Op0, Op1, isExact, Query (DL, TLI, DT, AT, CxtI),
1448 static Value *simplifyUnsignedRangeCheck(ICmpInst *ZeroICmp,
1449 ICmpInst *UnsignedICmp, bool IsAnd) {
1452 ICmpInst::Predicate EqPred;
1453 if (!match(ZeroICmp, m_ICmp(EqPred, m_Value(Y), m_Zero())) ||
1454 !ICmpInst::isEquality(EqPred))
1457 ICmpInst::Predicate UnsignedPred;
1458 if (match(UnsignedICmp, m_ICmp(UnsignedPred, m_Value(X), m_Specific(Y))) &&
1459 ICmpInst::isUnsigned(UnsignedPred))
1461 else if (match(UnsignedICmp,
1462 m_ICmp(UnsignedPred, m_Value(Y), m_Specific(X))) &&
1463 ICmpInst::isUnsigned(UnsignedPred))
1464 UnsignedPred = ICmpInst::getSwappedPredicate(UnsignedPred);
1468 // X < Y && Y != 0 --> X < Y
1469 // X < Y || Y != 0 --> Y != 0
1470 if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_NE)
1471 return IsAnd ? UnsignedICmp : ZeroICmp;
1473 // X >= Y || Y != 0 --> true
1474 // X >= Y || Y == 0 --> X >= Y
1475 if (UnsignedPred == ICmpInst::ICMP_UGE && !IsAnd) {
1476 if (EqPred == ICmpInst::ICMP_NE)
1477 return getTrue(UnsignedICmp->getType());
1478 return UnsignedICmp;
1481 // X < Y && Y == 0 --> false
1482 if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_EQ &&
1484 return getFalse(UnsignedICmp->getType());
1489 // Simplify (and (icmp ...) (icmp ...)) to true when we can tell that the range
1490 // of possible values cannot be satisfied.
1491 static Value *SimplifyAndOfICmps(ICmpInst *Op0, ICmpInst *Op1) {
1492 ICmpInst::Predicate Pred0, Pred1;
1493 ConstantInt *CI1, *CI2;
1496 if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/true))
1499 if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_ConstantInt(CI1)),
1500 m_ConstantInt(CI2))))
1503 if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Specific(CI1))))
1506 Type *ITy = Op0->getType();
1508 auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1509 bool isNSW = AddInst->hasNoSignedWrap();
1510 bool isNUW = AddInst->hasNoUnsignedWrap();
1512 const APInt &CI1V = CI1->getValue();
1513 const APInt &CI2V = CI2->getValue();
1514 const APInt Delta = CI2V - CI1V;
1515 if (CI1V.isStrictlyPositive()) {
1517 if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_SGT)
1518 return getFalse(ITy);
1519 if (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1520 return getFalse(ITy);
1523 if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_SGT)
1524 return getFalse(ITy);
1525 if (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1526 return getFalse(ITy);
1529 if (CI1V.getBoolValue() && isNUW) {
1531 if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT)
1532 return getFalse(ITy);
1534 if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGT)
1535 return getFalse(ITy);
1541 /// SimplifyAndInst - Given operands for an And, see if we can
1542 /// fold the result. If not, this returns null.
1543 static Value *SimplifyAndInst(Value *Op0, Value *Op1, const Query &Q,
1544 unsigned MaxRecurse) {
1545 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1546 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1547 Constant *Ops[] = { CLHS, CRHS };
1548 return ConstantFoldInstOperands(Instruction::And, CLHS->getType(),
1552 // Canonicalize the constant to the RHS.
1553 std::swap(Op0, Op1);
1557 if (match(Op1, m_Undef()))
1558 return Constant::getNullValue(Op0->getType());
1565 if (match(Op1, m_Zero()))
1569 if (match(Op1, m_AllOnes()))
1572 // A & ~A = ~A & A = 0
1573 if (match(Op0, m_Not(m_Specific(Op1))) ||
1574 match(Op1, m_Not(m_Specific(Op0))))
1575 return Constant::getNullValue(Op0->getType());
1578 Value *A = nullptr, *B = nullptr;
1579 if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
1580 (A == Op1 || B == Op1))
1584 if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
1585 (A == Op0 || B == Op0))
1588 // A & (-A) = A if A is a power of two or zero.
1589 if (match(Op0, m_Neg(m_Specific(Op1))) ||
1590 match(Op1, m_Neg(m_Specific(Op0)))) {
1591 if (isKnownToBeAPowerOfTwo(Op0, /*OrZero*/true, 0, Q.AT, Q.CxtI, Q.DT))
1593 if (isKnownToBeAPowerOfTwo(Op1, /*OrZero*/true, 0, Q.AT, Q.CxtI, Q.DT))
1597 if (auto *ICILHS = dyn_cast<ICmpInst>(Op0)) {
1598 if (auto *ICIRHS = dyn_cast<ICmpInst>(Op1)) {
1599 if (Value *V = SimplifyAndOfICmps(ICILHS, ICIRHS))
1601 if (Value *V = SimplifyAndOfICmps(ICIRHS, ICILHS))
1606 // Try some generic simplifications for associative operations.
1607 if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
1611 // And distributes over Or. Try some generic simplifications based on this.
1612 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1616 // And distributes over Xor. Try some generic simplifications based on this.
1617 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
1621 // If the operation is with the result of a select instruction, check whether
1622 // operating on either branch of the select always yields the same value.
1623 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1624 if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
1628 // If the operation is with the result of a phi instruction, check whether
1629 // operating on all incoming values of the phi always yields the same value.
1630 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1631 if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
1638 Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const DataLayout *DL,
1639 const TargetLibraryInfo *TLI,
1640 const DominatorTree *DT, AssumptionTracker *AT,
1641 const Instruction *CxtI) {
1642 return ::SimplifyAndInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1646 // Simplify (or (icmp ...) (icmp ...)) to true when we can tell that the union
1647 // contains all possible values.
1648 static Value *SimplifyOrOfICmps(ICmpInst *Op0, ICmpInst *Op1) {
1649 ICmpInst::Predicate Pred0, Pred1;
1650 ConstantInt *CI1, *CI2;
1653 if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/false))
1656 if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_ConstantInt(CI1)),
1657 m_ConstantInt(CI2))))
1660 if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Specific(CI1))))
1663 Type *ITy = Op0->getType();
1665 auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1666 bool isNSW = AddInst->hasNoSignedWrap();
1667 bool isNUW = AddInst->hasNoUnsignedWrap();
1669 const APInt &CI1V = CI1->getValue();
1670 const APInt &CI2V = CI2->getValue();
1671 const APInt Delta = CI2V - CI1V;
1672 if (CI1V.isStrictlyPositive()) {
1674 if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_SLE)
1675 return getTrue(ITy);
1676 if (Pred0 == ICmpInst::ICMP_SGE && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1677 return getTrue(ITy);
1680 if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_SLE)
1681 return getTrue(ITy);
1682 if (Pred0 == ICmpInst::ICMP_SGT && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1683 return getTrue(ITy);
1686 if (CI1V.getBoolValue() && isNUW) {
1688 if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_ULE)
1689 return getTrue(ITy);
1691 if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_ULE)
1692 return getTrue(ITy);
1698 /// SimplifyOrInst - Given operands for an Or, see if we can
1699 /// fold the result. If not, this returns null.
1700 static Value *SimplifyOrInst(Value *Op0, Value *Op1, const Query &Q,
1701 unsigned MaxRecurse) {
1702 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1703 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1704 Constant *Ops[] = { CLHS, CRHS };
1705 return ConstantFoldInstOperands(Instruction::Or, CLHS->getType(),
1709 // Canonicalize the constant to the RHS.
1710 std::swap(Op0, Op1);
1714 if (match(Op1, m_Undef()))
1715 return Constant::getAllOnesValue(Op0->getType());
1722 if (match(Op1, m_Zero()))
1726 if (match(Op1, m_AllOnes()))
1729 // A | ~A = ~A | A = -1
1730 if (match(Op0, m_Not(m_Specific(Op1))) ||
1731 match(Op1, m_Not(m_Specific(Op0))))
1732 return Constant::getAllOnesValue(Op0->getType());
1735 Value *A = nullptr, *B = nullptr;
1736 if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
1737 (A == Op1 || B == Op1))
1741 if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
1742 (A == Op0 || B == Op0))
1745 // ~(A & ?) | A = -1
1746 if (match(Op0, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1747 (A == Op1 || B == Op1))
1748 return Constant::getAllOnesValue(Op1->getType());
1750 // A | ~(A & ?) = -1
1751 if (match(Op1, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1752 (A == Op0 || B == Op0))
1753 return Constant::getAllOnesValue(Op0->getType());
1755 if (auto *ICILHS = dyn_cast<ICmpInst>(Op0)) {
1756 if (auto *ICIRHS = dyn_cast<ICmpInst>(Op1)) {
1757 if (Value *V = SimplifyOrOfICmps(ICILHS, ICIRHS))
1759 if (Value *V = SimplifyOrOfICmps(ICIRHS, ICILHS))
1764 // Try some generic simplifications for associative operations.
1765 if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
1769 // Or distributes over And. Try some generic simplifications based on this.
1770 if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
1774 // If the operation is with the result of a select instruction, check whether
1775 // operating on either branch of the select always yields the same value.
1776 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1777 if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
1782 Value *C = nullptr, *D = nullptr;
1783 if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
1784 match(Op1, m_And(m_Value(B), m_Value(D)))) {
1785 ConstantInt *C1 = dyn_cast<ConstantInt>(C);
1786 ConstantInt *C2 = dyn_cast<ConstantInt>(D);
1787 if (C1 && C2 && (C1->getValue() == ~C2->getValue())) {
1788 // (A & C1)|(B & C2)
1789 // If we have: ((V + N) & C1) | (V & C2)
1790 // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
1791 // replace with V+N.
1793 if ((C2->getValue() & (C2->getValue() + 1)) == 0 && // C2 == 0+1+
1794 match(A, m_Add(m_Value(V1), m_Value(V2)))) {
1795 // Add commutes, try both ways.
1796 if (V1 == B && MaskedValueIsZero(V2, C2->getValue(), Q.DL,
1797 0, Q.AT, Q.CxtI, Q.DT))
1799 if (V2 == B && MaskedValueIsZero(V1, C2->getValue(), Q.DL,
1800 0, Q.AT, Q.CxtI, Q.DT))
1803 // Or commutes, try both ways.
1804 if ((C1->getValue() & (C1->getValue() + 1)) == 0 &&
1805 match(B, m_Add(m_Value(V1), m_Value(V2)))) {
1806 // Add commutes, try both ways.
1807 if (V1 == A && MaskedValueIsZero(V2, C1->getValue(), Q.DL,
1808 0, Q.AT, Q.CxtI, Q.DT))
1810 if (V2 == A && MaskedValueIsZero(V1, C1->getValue(), Q.DL,
1811 0, Q.AT, Q.CxtI, Q.DT))
1817 // If the operation is with the result of a phi instruction, check whether
1818 // operating on all incoming values of the phi always yields the same value.
1819 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1820 if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
1826 Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const DataLayout *DL,
1827 const TargetLibraryInfo *TLI,
1828 const DominatorTree *DT, AssumptionTracker *AT,
1829 const Instruction *CxtI) {
1830 return ::SimplifyOrInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1834 /// SimplifyXorInst - Given operands for a Xor, see if we can
1835 /// fold the result. If not, this returns null.
1836 static Value *SimplifyXorInst(Value *Op0, Value *Op1, const Query &Q,
1837 unsigned MaxRecurse) {
1838 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1839 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1840 Constant *Ops[] = { CLHS, CRHS };
1841 return ConstantFoldInstOperands(Instruction::Xor, CLHS->getType(),
1845 // Canonicalize the constant to the RHS.
1846 std::swap(Op0, Op1);
1849 // A ^ undef -> undef
1850 if (match(Op1, m_Undef()))
1854 if (match(Op1, m_Zero()))
1859 return Constant::getNullValue(Op0->getType());
1861 // A ^ ~A = ~A ^ A = -1
1862 if (match(Op0, m_Not(m_Specific(Op1))) ||
1863 match(Op1, m_Not(m_Specific(Op0))))
1864 return Constant::getAllOnesValue(Op0->getType());
1866 // Try some generic simplifications for associative operations.
1867 if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
1871 // Threading Xor over selects and phi nodes is pointless, so don't bother.
1872 // Threading over the select in "A ^ select(cond, B, C)" means evaluating
1873 // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
1874 // only if B and C are equal. If B and C are equal then (since we assume
1875 // that operands have already been simplified) "select(cond, B, C)" should
1876 // have been simplified to the common value of B and C already. Analysing
1877 // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
1878 // for threading over phi nodes.
1883 Value *llvm::SimplifyXorInst(Value *Op0, Value *Op1, const DataLayout *DL,
1884 const TargetLibraryInfo *TLI,
1885 const DominatorTree *DT, AssumptionTracker *AT,
1886 const Instruction *CxtI) {
1887 return ::SimplifyXorInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1891 static Type *GetCompareTy(Value *Op) {
1892 return CmpInst::makeCmpResultType(Op->getType());
1895 /// ExtractEquivalentCondition - Rummage around inside V looking for something
1896 /// equivalent to the comparison "LHS Pred RHS". Return such a value if found,
1897 /// otherwise return null. Helper function for analyzing max/min idioms.
1898 static Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred,
1899 Value *LHS, Value *RHS) {
1900 SelectInst *SI = dyn_cast<SelectInst>(V);
1903 CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
1906 Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
1907 if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
1909 if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
1910 LHS == CmpRHS && RHS == CmpLHS)
1915 // A significant optimization not implemented here is assuming that alloca
1916 // addresses are not equal to incoming argument values. They don't *alias*,
1917 // as we say, but that doesn't mean they aren't equal, so we take a
1918 // conservative approach.
1920 // This is inspired in part by C++11 5.10p1:
1921 // "Two pointers of the same type compare equal if and only if they are both
1922 // null, both point to the same function, or both represent the same
1925 // This is pretty permissive.
1927 // It's also partly due to C11 6.5.9p6:
1928 // "Two pointers compare equal if and only if both are null pointers, both are
1929 // pointers to the same object (including a pointer to an object and a
1930 // subobject at its beginning) or function, both are pointers to one past the
1931 // last element of the same array object, or one is a pointer to one past the
1932 // end of one array object and the other is a pointer to the start of a
1933 // different array object that happens to immediately follow the first array
1934 // object in the address space.)
1936 // C11's version is more restrictive, however there's no reason why an argument
1937 // couldn't be a one-past-the-end value for a stack object in the caller and be
1938 // equal to the beginning of a stack object in the callee.
1940 // If the C and C++ standards are ever made sufficiently restrictive in this
1941 // area, it may be possible to update LLVM's semantics accordingly and reinstate
1942 // this optimization.
1943 static Constant *computePointerICmp(const DataLayout *DL,
1944 const TargetLibraryInfo *TLI,
1945 CmpInst::Predicate Pred,
1946 Value *LHS, Value *RHS) {
1947 // First, skip past any trivial no-ops.
1948 LHS = LHS->stripPointerCasts();
1949 RHS = RHS->stripPointerCasts();
1951 // A non-null pointer is not equal to a null pointer.
1952 if (llvm::isKnownNonNull(LHS, TLI) && isa<ConstantPointerNull>(RHS) &&
1953 (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE))
1954 return ConstantInt::get(GetCompareTy(LHS),
1955 !CmpInst::isTrueWhenEqual(Pred));
1957 // We can only fold certain predicates on pointer comparisons.
1962 // Equality comaprisons are easy to fold.
1963 case CmpInst::ICMP_EQ:
1964 case CmpInst::ICMP_NE:
1967 // We can only handle unsigned relational comparisons because 'inbounds' on
1968 // a GEP only protects against unsigned wrapping.
1969 case CmpInst::ICMP_UGT:
1970 case CmpInst::ICMP_UGE:
1971 case CmpInst::ICMP_ULT:
1972 case CmpInst::ICMP_ULE:
1973 // However, we have to switch them to their signed variants to handle
1974 // negative indices from the base pointer.
1975 Pred = ICmpInst::getSignedPredicate(Pred);
1979 // Strip off any constant offsets so that we can reason about them.
1980 // It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets
1981 // here and compare base addresses like AliasAnalysis does, however there are
1982 // numerous hazards. AliasAnalysis and its utilities rely on special rules
1983 // governing loads and stores which don't apply to icmps. Also, AliasAnalysis
1984 // doesn't need to guarantee pointer inequality when it says NoAlias.
1985 Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
1986 Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
1988 // If LHS and RHS are related via constant offsets to the same base
1989 // value, we can replace it with an icmp which just compares the offsets.
1991 return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset);
1993 // Various optimizations for (in)equality comparisons.
1994 if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE) {
1995 // Different non-empty allocations that exist at the same time have
1996 // different addresses (if the program can tell). Global variables always
1997 // exist, so they always exist during the lifetime of each other and all
1998 // allocas. Two different allocas usually have different addresses...
2000 // However, if there's an @llvm.stackrestore dynamically in between two
2001 // allocas, they may have the same address. It's tempting to reduce the
2002 // scope of the problem by only looking at *static* allocas here. That would
2003 // cover the majority of allocas while significantly reducing the likelihood
2004 // of having an @llvm.stackrestore pop up in the middle. However, it's not
2005 // actually impossible for an @llvm.stackrestore to pop up in the middle of
2006 // an entry block. Also, if we have a block that's not attached to a
2007 // function, we can't tell if it's "static" under the current definition.
2008 // Theoretically, this problem could be fixed by creating a new kind of
2009 // instruction kind specifically for static allocas. Such a new instruction
2010 // could be required to be at the top of the entry block, thus preventing it
2011 // from being subject to a @llvm.stackrestore. Instcombine could even
2012 // convert regular allocas into these special allocas. It'd be nifty.
2013 // However, until then, this problem remains open.
2015 // So, we'll assume that two non-empty allocas have different addresses
2018 // With all that, if the offsets are within the bounds of their allocations
2019 // (and not one-past-the-end! so we can't use inbounds!), and their
2020 // allocations aren't the same, the pointers are not equal.
2022 // Note that it's not necessary to check for LHS being a global variable
2023 // address, due to canonicalization and constant folding.
2024 if (isa<AllocaInst>(LHS) &&
2025 (isa<AllocaInst>(RHS) || isa<GlobalVariable>(RHS))) {
2026 ConstantInt *LHSOffsetCI = dyn_cast<ConstantInt>(LHSOffset);
2027 ConstantInt *RHSOffsetCI = dyn_cast<ConstantInt>(RHSOffset);
2028 uint64_t LHSSize, RHSSize;
2029 if (LHSOffsetCI && RHSOffsetCI &&
2030 getObjectSize(LHS, LHSSize, DL, TLI) &&
2031 getObjectSize(RHS, RHSSize, DL, TLI)) {
2032 const APInt &LHSOffsetValue = LHSOffsetCI->getValue();
2033 const APInt &RHSOffsetValue = RHSOffsetCI->getValue();
2034 if (!LHSOffsetValue.isNegative() &&
2035 !RHSOffsetValue.isNegative() &&
2036 LHSOffsetValue.ult(LHSSize) &&
2037 RHSOffsetValue.ult(RHSSize)) {
2038 return ConstantInt::get(GetCompareTy(LHS),
2039 !CmpInst::isTrueWhenEqual(Pred));
2043 // Repeat the above check but this time without depending on DataLayout
2044 // or being able to compute a precise size.
2045 if (!cast<PointerType>(LHS->getType())->isEmptyTy() &&
2046 !cast<PointerType>(RHS->getType())->isEmptyTy() &&
2047 LHSOffset->isNullValue() &&
2048 RHSOffset->isNullValue())
2049 return ConstantInt::get(GetCompareTy(LHS),
2050 !CmpInst::isTrueWhenEqual(Pred));
2053 // Even if an non-inbounds GEP occurs along the path we can still optimize
2054 // equality comparisons concerning the result. We avoid walking the whole
2055 // chain again by starting where the last calls to
2056 // stripAndComputeConstantOffsets left off and accumulate the offsets.
2057 Constant *LHSNoBound = stripAndComputeConstantOffsets(DL, LHS, true);
2058 Constant *RHSNoBound = stripAndComputeConstantOffsets(DL, RHS, true);
2060 return ConstantExpr::getICmp(Pred,
2061 ConstantExpr::getAdd(LHSOffset, LHSNoBound),
2062 ConstantExpr::getAdd(RHSOffset, RHSNoBound));
2064 // If one side of the equality comparison must come from a noalias call
2065 // (meaning a system memory allocation function), and the other side must
2066 // come from a pointer that cannot overlap with dynamically-allocated
2067 // memory within the lifetime of the current function (allocas, byval
2068 // arguments, globals), then determine the comparison result here.
2069 SmallVector<Value *, 8> LHSUObjs, RHSUObjs;
2070 GetUnderlyingObjects(LHS, LHSUObjs, DL);
2071 GetUnderlyingObjects(RHS, RHSUObjs, DL);
2073 // Is the set of underlying objects all noalias calls?
2074 auto IsNAC = [](SmallVectorImpl<Value *> &Objects) {
2075 return std::all_of(Objects.begin(), Objects.end(),
2076 [](Value *V){ return isNoAliasCall(V); });
2079 // Is the set of underlying objects all things which must be disjoint from
2080 // noalias calls. For allocas, we consider only static ones (dynamic
2081 // allocas might be transformed into calls to malloc not simultaneously
2082 // live with the compared-to allocation). For globals, we exclude symbols
2083 // that might be resolve lazily to symbols in another dynamically-loaded
2084 // library (and, thus, could be malloc'ed by the implementation).
2085 auto IsAllocDisjoint = [](SmallVectorImpl<Value *> &Objects) {
2086 return std::all_of(Objects.begin(), Objects.end(),
2088 if (const AllocaInst *AI = dyn_cast<AllocaInst>(V))
2089 return AI->getParent() && AI->getParent()->getParent() &&
2090 AI->isStaticAlloca();
2091 if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
2092 return (GV->hasLocalLinkage() ||
2093 GV->hasHiddenVisibility() ||
2094 GV->hasProtectedVisibility() ||
2095 GV->hasUnnamedAddr()) &&
2096 !GV->isThreadLocal();
2097 if (const Argument *A = dyn_cast<Argument>(V))
2098 return A->hasByValAttr();
2103 if ((IsNAC(LHSUObjs) && IsAllocDisjoint(RHSUObjs)) ||
2104 (IsNAC(RHSUObjs) && IsAllocDisjoint(LHSUObjs)))
2105 return ConstantInt::get(GetCompareTy(LHS),
2106 !CmpInst::isTrueWhenEqual(Pred));
2113 /// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
2114 /// fold the result. If not, this returns null.
2115 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2116 const Query &Q, unsigned MaxRecurse) {
2117 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
2118 assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
2120 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
2121 if (Constant *CRHS = dyn_cast<Constant>(RHS))
2122 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
2124 // If we have a constant, make sure it is on the RHS.
2125 std::swap(LHS, RHS);
2126 Pred = CmpInst::getSwappedPredicate(Pred);
2129 Type *ITy = GetCompareTy(LHS); // The return type.
2130 Type *OpTy = LHS->getType(); // The operand type.
2132 // icmp X, X -> true/false
2133 // X icmp undef -> true/false. For example, icmp ugt %X, undef -> false
2134 // because X could be 0.
2135 if (LHS == RHS || isa<UndefValue>(RHS))
2136 return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
2138 // Special case logic when the operands have i1 type.
2139 if (OpTy->getScalarType()->isIntegerTy(1)) {
2142 case ICmpInst::ICMP_EQ:
2144 if (match(RHS, m_One()))
2147 case ICmpInst::ICMP_NE:
2149 if (match(RHS, m_Zero()))
2152 case ICmpInst::ICMP_UGT:
2154 if (match(RHS, m_Zero()))
2157 case ICmpInst::ICMP_UGE:
2159 if (match(RHS, m_One()))
2162 case ICmpInst::ICMP_SLT:
2164 if (match(RHS, m_Zero()))
2167 case ICmpInst::ICMP_SLE:
2169 if (match(RHS, m_One()))
2175 // If we are comparing with zero then try hard since this is a common case.
2176 if (match(RHS, m_Zero())) {
2177 bool LHSKnownNonNegative, LHSKnownNegative;
2179 default: llvm_unreachable("Unknown ICmp predicate!");
2180 case ICmpInst::ICMP_ULT:
2181 return getFalse(ITy);
2182 case ICmpInst::ICMP_UGE:
2183 return getTrue(ITy);
2184 case ICmpInst::ICMP_EQ:
2185 case ICmpInst::ICMP_ULE:
2186 if (isKnownNonZero(LHS, Q.DL, 0, Q.AT, Q.CxtI, Q.DT))
2187 return getFalse(ITy);
2189 case ICmpInst::ICMP_NE:
2190 case ICmpInst::ICMP_UGT:
2191 if (isKnownNonZero(LHS, Q.DL, 0, Q.AT, Q.CxtI, Q.DT))
2192 return getTrue(ITy);
2194 case ICmpInst::ICMP_SLT:
2195 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL,
2196 0, Q.AT, Q.CxtI, Q.DT);
2197 if (LHSKnownNegative)
2198 return getTrue(ITy);
2199 if (LHSKnownNonNegative)
2200 return getFalse(ITy);
2202 case ICmpInst::ICMP_SLE:
2203 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL,
2204 0, Q.AT, Q.CxtI, Q.DT);
2205 if (LHSKnownNegative)
2206 return getTrue(ITy);
2207 if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.DL,
2208 0, Q.AT, Q.CxtI, Q.DT))
2209 return getFalse(ITy);
2211 case ICmpInst::ICMP_SGE:
2212 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL,
2213 0, Q.AT, Q.CxtI, Q.DT);
2214 if (LHSKnownNegative)
2215 return getFalse(ITy);
2216 if (LHSKnownNonNegative)
2217 return getTrue(ITy);
2219 case ICmpInst::ICMP_SGT:
2220 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL,
2221 0, Q.AT, Q.CxtI, Q.DT);
2222 if (LHSKnownNegative)
2223 return getFalse(ITy);
2224 if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.DL,
2225 0, Q.AT, Q.CxtI, Q.DT))
2226 return getTrue(ITy);
2231 // See if we are doing a comparison with a constant integer.
2232 if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2233 // Rule out tautological comparisons (eg., ult 0 or uge 0).
2234 ConstantRange RHS_CR = ICmpInst::makeConstantRange(Pred, CI->getValue());
2235 if (RHS_CR.isEmptySet())
2236 return ConstantInt::getFalse(CI->getContext());
2237 if (RHS_CR.isFullSet())
2238 return ConstantInt::getTrue(CI->getContext());
2240 // Many binary operators with constant RHS have easy to compute constant
2241 // range. Use them to check whether the comparison is a tautology.
2242 unsigned Width = CI->getBitWidth();
2243 APInt Lower = APInt(Width, 0);
2244 APInt Upper = APInt(Width, 0);
2246 if (match(LHS, m_URem(m_Value(), m_ConstantInt(CI2)))) {
2247 // 'urem x, CI2' produces [0, CI2).
2248 Upper = CI2->getValue();
2249 } else if (match(LHS, m_SRem(m_Value(), m_ConstantInt(CI2)))) {
2250 // 'srem x, CI2' produces (-|CI2|, |CI2|).
2251 Upper = CI2->getValue().abs();
2252 Lower = (-Upper) + 1;
2253 } else if (match(LHS, m_UDiv(m_ConstantInt(CI2), m_Value()))) {
2254 // 'udiv CI2, x' produces [0, CI2].
2255 Upper = CI2->getValue() + 1;
2256 } else if (match(LHS, m_UDiv(m_Value(), m_ConstantInt(CI2)))) {
2257 // 'udiv x, CI2' produces [0, UINT_MAX / CI2].
2258 APInt NegOne = APInt::getAllOnesValue(Width);
2260 Upper = NegOne.udiv(CI2->getValue()) + 1;
2261 } else if (match(LHS, m_SDiv(m_ConstantInt(CI2), m_Value()))) {
2262 if (CI2->isMinSignedValue()) {
2263 // 'sdiv INT_MIN, x' produces [INT_MIN, INT_MIN / -2].
2264 Lower = CI2->getValue();
2265 Upper = Lower.lshr(1) + 1;
2267 // 'sdiv CI2, x' produces [-|CI2|, |CI2|].
2268 Upper = CI2->getValue().abs() + 1;
2269 Lower = (-Upper) + 1;
2271 } else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) {
2272 APInt IntMin = APInt::getSignedMinValue(Width);
2273 APInt IntMax = APInt::getSignedMaxValue(Width);
2274 APInt Val = CI2->getValue();
2275 if (Val.isAllOnesValue()) {
2276 // 'sdiv x, -1' produces [INT_MIN + 1, INT_MAX]
2277 // where CI2 != -1 and CI2 != 0 and CI2 != 1
2280 } else if (Val.countLeadingZeros() < Width - 1) {
2281 // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2]
2282 // where CI2 != -1 and CI2 != 0 and CI2 != 1
2283 Lower = IntMin.sdiv(Val);
2284 Upper = IntMax.sdiv(Val);
2285 if (Lower.sgt(Upper))
2286 std::swap(Lower, Upper);
2288 assert(Upper != Lower && "Upper part of range has wrapped!");
2290 } else if (match(LHS, m_NUWShl(m_ConstantInt(CI2), m_Value()))) {
2291 // 'shl nuw CI2, x' produces [CI2, CI2 << CLZ(CI2)]
2292 Lower = CI2->getValue();
2293 Upper = Lower.shl(Lower.countLeadingZeros()) + 1;
2294 } else if (match(LHS, m_NSWShl(m_ConstantInt(CI2), m_Value()))) {
2295 if (CI2->isNegative()) {
2296 // 'shl nsw CI2, x' produces [CI2 << CLO(CI2)-1, CI2]
2297 unsigned ShiftAmount = CI2->getValue().countLeadingOnes() - 1;
2298 Lower = CI2->getValue().shl(ShiftAmount);
2299 Upper = CI2->getValue() + 1;
2301 // 'shl nsw CI2, x' produces [CI2, CI2 << CLZ(CI2)-1]
2302 unsigned ShiftAmount = CI2->getValue().countLeadingZeros() - 1;
2303 Lower = CI2->getValue();
2304 Upper = CI2->getValue().shl(ShiftAmount) + 1;
2306 } else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) {
2307 // 'lshr x, CI2' produces [0, UINT_MAX >> CI2].
2308 APInt NegOne = APInt::getAllOnesValue(Width);
2309 if (CI2->getValue().ult(Width))
2310 Upper = NegOne.lshr(CI2->getValue()) + 1;
2311 } else if (match(LHS, m_LShr(m_ConstantInt(CI2), m_Value()))) {
2312 // 'lshr CI2, x' produces [CI2 >> (Width-1), CI2].
2313 unsigned ShiftAmount = Width - 1;
2314 if (!CI2->isZero() && cast<BinaryOperator>(LHS)->isExact())
2315 ShiftAmount = CI2->getValue().countTrailingZeros();
2316 Lower = CI2->getValue().lshr(ShiftAmount);
2317 Upper = CI2->getValue() + 1;
2318 } else if (match(LHS, m_AShr(m_Value(), m_ConstantInt(CI2)))) {
2319 // 'ashr x, CI2' produces [INT_MIN >> CI2, INT_MAX >> CI2].
2320 APInt IntMin = APInt::getSignedMinValue(Width);
2321 APInt IntMax = APInt::getSignedMaxValue(Width);
2322 if (CI2->getValue().ult(Width)) {
2323 Lower = IntMin.ashr(CI2->getValue());
2324 Upper = IntMax.ashr(CI2->getValue()) + 1;
2326 } else if (match(LHS, m_AShr(m_ConstantInt(CI2), m_Value()))) {
2327 unsigned ShiftAmount = Width - 1;
2328 if (!CI2->isZero() && cast<BinaryOperator>(LHS)->isExact())
2329 ShiftAmount = CI2->getValue().countTrailingZeros();
2330 if (CI2->isNegative()) {
2331 // 'ashr CI2, x' produces [CI2, CI2 >> (Width-1)]
2332 Lower = CI2->getValue();
2333 Upper = CI2->getValue().ashr(ShiftAmount) + 1;
2335 // 'ashr CI2, x' produces [CI2 >> (Width-1), CI2]
2336 Lower = CI2->getValue().ashr(ShiftAmount);
2337 Upper = CI2->getValue() + 1;
2339 } else if (match(LHS, m_Or(m_Value(), m_ConstantInt(CI2)))) {
2340 // 'or x, CI2' produces [CI2, UINT_MAX].
2341 Lower = CI2->getValue();
2342 } else if (match(LHS, m_And(m_Value(), m_ConstantInt(CI2)))) {
2343 // 'and x, CI2' produces [0, CI2].
2344 Upper = CI2->getValue() + 1;
2346 if (Lower != Upper) {
2347 ConstantRange LHS_CR = ConstantRange(Lower, Upper);
2348 if (RHS_CR.contains(LHS_CR))
2349 return ConstantInt::getTrue(RHS->getContext());
2350 if (RHS_CR.inverse().contains(LHS_CR))
2351 return ConstantInt::getFalse(RHS->getContext());
2355 // Compare of cast, for example (zext X) != 0 -> X != 0
2356 if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
2357 Instruction *LI = cast<CastInst>(LHS);
2358 Value *SrcOp = LI->getOperand(0);
2359 Type *SrcTy = SrcOp->getType();
2360 Type *DstTy = LI->getType();
2362 // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
2363 // if the integer type is the same size as the pointer type.
2364 if (MaxRecurse && Q.DL && isa<PtrToIntInst>(LI) &&
2365 Q.DL->getTypeSizeInBits(SrcTy) == DstTy->getPrimitiveSizeInBits()) {
2366 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
2367 // Transfer the cast to the constant.
2368 if (Value *V = SimplifyICmpInst(Pred, SrcOp,
2369 ConstantExpr::getIntToPtr(RHSC, SrcTy),
2372 } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
2373 if (RI->getOperand(0)->getType() == SrcTy)
2374 // Compare without the cast.
2375 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2381 if (isa<ZExtInst>(LHS)) {
2382 // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
2384 if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
2385 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2386 // Compare X and Y. Note that signed predicates become unsigned.
2387 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
2388 SrcOp, RI->getOperand(0), Q,
2392 // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
2393 // too. If not, then try to deduce the result of the comparison.
2394 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2395 // Compute the constant that would happen if we truncated to SrcTy then
2396 // reextended to DstTy.
2397 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2398 Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
2400 // If the re-extended constant didn't change then this is effectively
2401 // also a case of comparing two zero-extended values.
2402 if (RExt == CI && MaxRecurse)
2403 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
2404 SrcOp, Trunc, Q, MaxRecurse-1))
2407 // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
2408 // there. Use this to work out the result of the comparison.
2411 default: llvm_unreachable("Unknown ICmp predicate!");
2413 case ICmpInst::ICMP_EQ:
2414 case ICmpInst::ICMP_UGT:
2415 case ICmpInst::ICMP_UGE:
2416 return ConstantInt::getFalse(CI->getContext());
2418 case ICmpInst::ICMP_NE:
2419 case ICmpInst::ICMP_ULT:
2420 case ICmpInst::ICMP_ULE:
2421 return ConstantInt::getTrue(CI->getContext());
2423 // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
2424 // is non-negative then LHS <s RHS.
2425 case ICmpInst::ICMP_SGT:
2426 case ICmpInst::ICMP_SGE:
2427 return CI->getValue().isNegative() ?
2428 ConstantInt::getTrue(CI->getContext()) :
2429 ConstantInt::getFalse(CI->getContext());
2431 case ICmpInst::ICMP_SLT:
2432 case ICmpInst::ICMP_SLE:
2433 return CI->getValue().isNegative() ?
2434 ConstantInt::getFalse(CI->getContext()) :
2435 ConstantInt::getTrue(CI->getContext());
2441 if (isa<SExtInst>(LHS)) {
2442 // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
2444 if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
2445 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2446 // Compare X and Y. Note that the predicate does not change.
2447 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2451 // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
2452 // too. If not, then try to deduce the result of the comparison.
2453 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2454 // Compute the constant that would happen if we truncated to SrcTy then
2455 // reextended to DstTy.
2456 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2457 Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
2459 // If the re-extended constant didn't change then this is effectively
2460 // also a case of comparing two sign-extended values.
2461 if (RExt == CI && MaxRecurse)
2462 if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
2465 // Otherwise the upper bits of LHS are all equal, while RHS has varying
2466 // bits there. Use this to work out the result of the comparison.
2469 default: llvm_unreachable("Unknown ICmp predicate!");
2470 case ICmpInst::ICMP_EQ:
2471 return ConstantInt::getFalse(CI->getContext());
2472 case ICmpInst::ICMP_NE:
2473 return ConstantInt::getTrue(CI->getContext());
2475 // If RHS is non-negative then LHS <s RHS. If RHS is negative then
2477 case ICmpInst::ICMP_SGT:
2478 case ICmpInst::ICMP_SGE:
2479 return CI->getValue().isNegative() ?
2480 ConstantInt::getTrue(CI->getContext()) :
2481 ConstantInt::getFalse(CI->getContext());
2482 case ICmpInst::ICMP_SLT:
2483 case ICmpInst::ICMP_SLE:
2484 return CI->getValue().isNegative() ?
2485 ConstantInt::getFalse(CI->getContext()) :
2486 ConstantInt::getTrue(CI->getContext());
2488 // If LHS is non-negative then LHS <u RHS. If LHS is negative then
2490 case ICmpInst::ICMP_UGT:
2491 case ICmpInst::ICMP_UGE:
2492 // Comparison is true iff the LHS <s 0.
2494 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
2495 Constant::getNullValue(SrcTy),
2499 case ICmpInst::ICMP_ULT:
2500 case ICmpInst::ICMP_ULE:
2501 // Comparison is true iff the LHS >=s 0.
2503 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
2504 Constant::getNullValue(SrcTy),
2514 // Special logic for binary operators.
2515 BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
2516 BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
2517 if (MaxRecurse && (LBO || RBO)) {
2518 // Analyze the case when either LHS or RHS is an add instruction.
2519 Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
2520 // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
2521 bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
2522 if (LBO && LBO->getOpcode() == Instruction::Add) {
2523 A = LBO->getOperand(0); B = LBO->getOperand(1);
2524 NoLHSWrapProblem = ICmpInst::isEquality(Pred) ||
2525 (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
2526 (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
2528 if (RBO && RBO->getOpcode() == Instruction::Add) {
2529 C = RBO->getOperand(0); D = RBO->getOperand(1);
2530 NoRHSWrapProblem = ICmpInst::isEquality(Pred) ||
2531 (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
2532 (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
2535 // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
2536 if ((A == RHS || B == RHS) && NoLHSWrapProblem)
2537 if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
2538 Constant::getNullValue(RHS->getType()),
2542 // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
2543 if ((C == LHS || D == LHS) && NoRHSWrapProblem)
2544 if (Value *V = SimplifyICmpInst(Pred,
2545 Constant::getNullValue(LHS->getType()),
2546 C == LHS ? D : C, Q, MaxRecurse-1))
2549 // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
2550 if (A && C && (A == C || A == D || B == C || B == D) &&
2551 NoLHSWrapProblem && NoRHSWrapProblem) {
2552 // Determine Y and Z in the form icmp (X+Y), (X+Z).
2555 // C + B == C + D -> B == D
2558 } else if (A == D) {
2559 // D + B == C + D -> B == C
2562 } else if (B == C) {
2563 // A + C == C + D -> A == D
2568 // A + D == C + D -> A == C
2572 if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse-1))
2577 // icmp pred (or X, Y), X
2578 if (LBO && match(LBO, m_CombineOr(m_Or(m_Value(), m_Specific(RHS)),
2579 m_Or(m_Specific(RHS), m_Value())))) {
2580 if (Pred == ICmpInst::ICMP_ULT)
2581 return getFalse(ITy);
2582 if (Pred == ICmpInst::ICMP_UGE)
2583 return getTrue(ITy);
2585 // icmp pred X, (or X, Y)
2586 if (RBO && match(RBO, m_CombineOr(m_Or(m_Value(), m_Specific(LHS)),
2587 m_Or(m_Specific(LHS), m_Value())))) {
2588 if (Pred == ICmpInst::ICMP_ULE)
2589 return getTrue(ITy);
2590 if (Pred == ICmpInst::ICMP_UGT)
2591 return getFalse(ITy);
2594 // icmp pred (and X, Y), X
2595 if (LBO && match(LBO, m_CombineOr(m_And(m_Value(), m_Specific(RHS)),
2596 m_And(m_Specific(RHS), m_Value())))) {
2597 if (Pred == ICmpInst::ICMP_UGT)
2598 return getFalse(ITy);
2599 if (Pred == ICmpInst::ICMP_ULE)
2600 return getTrue(ITy);
2602 // icmp pred X, (and X, Y)
2603 if (RBO && match(RBO, m_CombineOr(m_And(m_Value(), m_Specific(LHS)),
2604 m_And(m_Specific(LHS), m_Value())))) {
2605 if (Pred == ICmpInst::ICMP_UGE)
2606 return getTrue(ITy);
2607 if (Pred == ICmpInst::ICMP_ULT)
2608 return getFalse(ITy);
2611 // 0 - (zext X) pred C
2612 if (!CmpInst::isUnsigned(Pred) && match(LHS, m_Neg(m_ZExt(m_Value())))) {
2613 if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS)) {
2614 if (RHSC->getValue().isStrictlyPositive()) {
2615 if (Pred == ICmpInst::ICMP_SLT)
2616 return ConstantInt::getTrue(RHSC->getContext());
2617 if (Pred == ICmpInst::ICMP_SGE)
2618 return ConstantInt::getFalse(RHSC->getContext());
2619 if (Pred == ICmpInst::ICMP_EQ)
2620 return ConstantInt::getFalse(RHSC->getContext());
2621 if (Pred == ICmpInst::ICMP_NE)
2622 return ConstantInt::getTrue(RHSC->getContext());
2624 if (RHSC->getValue().isNonNegative()) {
2625 if (Pred == ICmpInst::ICMP_SLE)
2626 return ConstantInt::getTrue(RHSC->getContext());
2627 if (Pred == ICmpInst::ICMP_SGT)
2628 return ConstantInt::getFalse(RHSC->getContext());
2633 // icmp pred (urem X, Y), Y
2634 if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
2635 bool KnownNonNegative, KnownNegative;
2639 case ICmpInst::ICMP_SGT:
2640 case ICmpInst::ICMP_SGE:
2641 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.DL,
2642 0, Q.AT, Q.CxtI, Q.DT);
2643 if (!KnownNonNegative)
2646 case ICmpInst::ICMP_EQ:
2647 case ICmpInst::ICMP_UGT:
2648 case ICmpInst::ICMP_UGE:
2649 return getFalse(ITy);
2650 case ICmpInst::ICMP_SLT:
2651 case ICmpInst::ICMP_SLE:
2652 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.DL,
2653 0, Q.AT, Q.CxtI, Q.DT);
2654 if (!KnownNonNegative)
2657 case ICmpInst::ICMP_NE:
2658 case ICmpInst::ICMP_ULT:
2659 case ICmpInst::ICMP_ULE:
2660 return getTrue(ITy);
2664 // icmp pred X, (urem Y, X)
2665 if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
2666 bool KnownNonNegative, KnownNegative;
2670 case ICmpInst::ICMP_SGT:
2671 case ICmpInst::ICMP_SGE:
2672 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.DL,
2673 0, Q.AT, Q.CxtI, Q.DT);
2674 if (!KnownNonNegative)
2677 case ICmpInst::ICMP_NE:
2678 case ICmpInst::ICMP_UGT:
2679 case ICmpInst::ICMP_UGE:
2680 return getTrue(ITy);
2681 case ICmpInst::ICMP_SLT:
2682 case ICmpInst::ICMP_SLE:
2683 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.DL,
2684 0, Q.AT, Q.CxtI, Q.DT);
2685 if (!KnownNonNegative)
2688 case ICmpInst::ICMP_EQ:
2689 case ICmpInst::ICMP_ULT:
2690 case ICmpInst::ICMP_ULE:
2691 return getFalse(ITy);
2696 if (LBO && match(LBO, m_UDiv(m_Specific(RHS), m_Value()))) {
2697 // icmp pred (X /u Y), X
2698 if (Pred == ICmpInst::ICMP_UGT)
2699 return getFalse(ITy);
2700 if (Pred == ICmpInst::ICMP_ULE)
2701 return getTrue(ITy);
2708 // where CI2 is a power of 2 and CI isn't
2709 if (auto *CI = dyn_cast<ConstantInt>(RHS)) {
2710 const APInt *CI2Val, *CIVal = &CI->getValue();
2711 if (LBO && match(LBO, m_Shl(m_APInt(CI2Val), m_Value())) &&
2712 CI2Val->isPowerOf2()) {
2713 if (!CIVal->isPowerOf2()) {
2714 // CI2 << X can equal zero in some circumstances,
2715 // this simplification is unsafe if CI is zero.
2717 // We know it is safe if:
2718 // - The shift is nsw, we can't shift out the one bit.
2719 // - The shift is nuw, we can't shift out the one bit.
2722 if (LBO->hasNoSignedWrap() || LBO->hasNoUnsignedWrap() ||
2723 *CI2Val == 1 || !CI->isZero()) {
2724 if (Pred == ICmpInst::ICMP_EQ)
2725 return ConstantInt::getFalse(RHS->getContext());
2726 if (Pred == ICmpInst::ICMP_NE)
2727 return ConstantInt::getTrue(RHS->getContext());
2730 if (CIVal->isSignBit() && *CI2Val == 1) {
2731 if (Pred == ICmpInst::ICMP_UGT)
2732 return ConstantInt::getFalse(RHS->getContext());
2733 if (Pred == ICmpInst::ICMP_ULE)
2734 return ConstantInt::getTrue(RHS->getContext());
2739 if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
2740 LBO->getOperand(1) == RBO->getOperand(1)) {
2741 switch (LBO->getOpcode()) {
2743 case Instruction::UDiv:
2744 case Instruction::LShr:
2745 if (ICmpInst::isSigned(Pred))
2748 case Instruction::SDiv:
2749 case Instruction::AShr:
2750 if (!LBO->isExact() || !RBO->isExact())
2752 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2753 RBO->getOperand(0), Q, MaxRecurse-1))
2756 case Instruction::Shl: {
2757 bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
2758 bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
2761 if (!NSW && ICmpInst::isSigned(Pred))
2763 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2764 RBO->getOperand(0), Q, MaxRecurse-1))
2771 // Simplify comparisons involving max/min.
2773 CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE;
2774 CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
2776 // Signed variants on "max(a,b)>=a -> true".
2777 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2778 if (A != RHS) std::swap(A, B); // smax(A, B) pred A.
2779 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2780 // We analyze this as smax(A, B) pred A.
2782 } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
2783 (A == LHS || B == LHS)) {
2784 if (A != LHS) std::swap(A, B); // A pred smax(A, B).
2785 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2786 // We analyze this as smax(A, B) swapped-pred A.
2787 P = CmpInst::getSwappedPredicate(Pred);
2788 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2789 (A == RHS || B == RHS)) {
2790 if (A != RHS) std::swap(A, B); // smin(A, B) pred A.
2791 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2792 // We analyze this as smax(-A, -B) swapped-pred -A.
2793 // Note that we do not need to actually form -A or -B thanks to EqP.
2794 P = CmpInst::getSwappedPredicate(Pred);
2795 } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
2796 (A == LHS || B == LHS)) {
2797 if (A != LHS) std::swap(A, B); // A pred smin(A, B).
2798 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2799 // We analyze this as smax(-A, -B) pred -A.
2800 // Note that we do not need to actually form -A or -B thanks to EqP.
2803 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2804 // Cases correspond to "max(A, B) p A".
2808 case CmpInst::ICMP_EQ:
2809 case CmpInst::ICMP_SLE:
2810 // Equivalent to "A EqP B". This may be the same as the condition tested
2811 // in the max/min; if so, we can just return that.
2812 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2814 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2816 // Otherwise, see if "A EqP B" simplifies.
2818 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2821 case CmpInst::ICMP_NE:
2822 case CmpInst::ICMP_SGT: {
2823 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2824 // Equivalent to "A InvEqP B". This may be the same as the condition
2825 // tested in the max/min; if so, we can just return that.
2826 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2828 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2830 // Otherwise, see if "A InvEqP B" simplifies.
2832 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2836 case CmpInst::ICMP_SGE:
2838 return getTrue(ITy);
2839 case CmpInst::ICMP_SLT:
2841 return getFalse(ITy);
2845 // Unsigned variants on "max(a,b)>=a -> true".
2846 P = CmpInst::BAD_ICMP_PREDICATE;
2847 if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2848 if (A != RHS) std::swap(A, B); // umax(A, B) pred A.
2849 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2850 // We analyze this as umax(A, B) pred A.
2852 } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
2853 (A == LHS || B == LHS)) {
2854 if (A != LHS) std::swap(A, B); // A pred umax(A, B).
2855 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2856 // We analyze this as umax(A, B) swapped-pred A.
2857 P = CmpInst::getSwappedPredicate(Pred);
2858 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2859 (A == RHS || B == RHS)) {
2860 if (A != RHS) std::swap(A, B); // umin(A, B) pred A.
2861 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2862 // We analyze this as umax(-A, -B) swapped-pred -A.
2863 // Note that we do not need to actually form -A or -B thanks to EqP.
2864 P = CmpInst::getSwappedPredicate(Pred);
2865 } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
2866 (A == LHS || B == LHS)) {
2867 if (A != LHS) std::swap(A, B); // A pred umin(A, B).
2868 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2869 // We analyze this as umax(-A, -B) pred -A.
2870 // Note that we do not need to actually form -A or -B thanks to EqP.
2873 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2874 // Cases correspond to "max(A, B) p A".
2878 case CmpInst::ICMP_EQ:
2879 case CmpInst::ICMP_ULE:
2880 // Equivalent to "A EqP B". This may be the same as the condition tested
2881 // in the max/min; if so, we can just return that.
2882 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2884 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2886 // Otherwise, see if "A EqP B" simplifies.
2888 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2891 case CmpInst::ICMP_NE:
2892 case CmpInst::ICMP_UGT: {
2893 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2894 // Equivalent to "A InvEqP B". This may be the same as the condition
2895 // tested in the max/min; if so, we can just return that.
2896 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2898 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2900 // Otherwise, see if "A InvEqP B" simplifies.
2902 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2906 case CmpInst::ICMP_UGE:
2908 return getTrue(ITy);
2909 case CmpInst::ICMP_ULT:
2911 return getFalse(ITy);
2915 // Variants on "max(x,y) >= min(x,z)".
2917 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
2918 match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
2919 (A == C || A == D || B == C || B == D)) {
2920 // max(x, ?) pred min(x, ?).
2921 if (Pred == CmpInst::ICMP_SGE)
2923 return getTrue(ITy);
2924 if (Pred == CmpInst::ICMP_SLT)
2926 return getFalse(ITy);
2927 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2928 match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
2929 (A == C || A == D || B == C || B == D)) {
2930 // min(x, ?) pred max(x, ?).
2931 if (Pred == CmpInst::ICMP_SLE)
2933 return getTrue(ITy);
2934 if (Pred == CmpInst::ICMP_SGT)
2936 return getFalse(ITy);
2937 } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
2938 match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
2939 (A == C || A == D || B == C || B == D)) {
2940 // max(x, ?) pred min(x, ?).
2941 if (Pred == CmpInst::ICMP_UGE)
2943 return getTrue(ITy);
2944 if (Pred == CmpInst::ICMP_ULT)
2946 return getFalse(ITy);
2947 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2948 match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
2949 (A == C || A == D || B == C || B == D)) {
2950 // min(x, ?) pred max(x, ?).
2951 if (Pred == CmpInst::ICMP_ULE)
2953 return getTrue(ITy);
2954 if (Pred == CmpInst::ICMP_UGT)
2956 return getFalse(ITy);
2959 // Simplify comparisons of related pointers using a powerful, recursive
2960 // GEP-walk when we have target data available..
2961 if (LHS->getType()->isPointerTy())
2962 if (Constant *C = computePointerICmp(Q.DL, Q.TLI, Pred, LHS, RHS))
2965 if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
2966 if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
2967 if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
2968 GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
2969 (ICmpInst::isEquality(Pred) ||
2970 (GLHS->isInBounds() && GRHS->isInBounds() &&
2971 Pred == ICmpInst::getSignedPredicate(Pred)))) {
2972 // The bases are equal and the indices are constant. Build a constant
2973 // expression GEP with the same indices and a null base pointer to see
2974 // what constant folding can make out of it.
2975 Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
2976 SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
2977 Constant *NewLHS = ConstantExpr::getGetElementPtr(Null, IndicesLHS);
2979 SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
2980 Constant *NewRHS = ConstantExpr::getGetElementPtr(Null, IndicesRHS);
2981 return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
2986 // If a bit is known to be zero for A and known to be one for B,
2987 // then A and B cannot be equal.
2988 if (ICmpInst::isEquality(Pred)) {
2989 if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2990 uint32_t BitWidth = CI->getBitWidth();
2991 APInt LHSKnownZero(BitWidth, 0);
2992 APInt LHSKnownOne(BitWidth, 0);
2993 computeKnownBits(LHS, LHSKnownZero, LHSKnownOne, Q.DL, /*Depth=*/0, Q.AT,
2995 const APInt &RHSVal = CI->getValue();
2996 if (((LHSKnownZero & RHSVal) != 0) || ((LHSKnownOne & ~RHSVal) != 0))
2997 return Pred == ICmpInst::ICMP_EQ
2998 ? ConstantInt::getFalse(CI->getContext())
2999 : ConstantInt::getTrue(CI->getContext());
3003 // If the comparison is with the result of a select instruction, check whether
3004 // comparing with either branch of the select always yields the same value.
3005 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3006 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
3009 // If the comparison is with the result of a phi instruction, check whether
3010 // doing the compare with each incoming phi value yields a common result.
3011 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3012 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
3018 Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3019 const DataLayout *DL,
3020 const TargetLibraryInfo *TLI,
3021 const DominatorTree *DT,
3022 AssumptionTracker *AT,
3023 Instruction *CxtI) {
3024 return ::SimplifyICmpInst(Predicate, LHS, RHS, Query (DL, TLI, DT, AT, CxtI),
3028 /// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can
3029 /// fold the result. If not, this returns null.
3030 static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3031 const Query &Q, unsigned MaxRecurse) {
3032 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
3033 assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
3035 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
3036 if (Constant *CRHS = dyn_cast<Constant>(RHS))
3037 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
3039 // If we have a constant, make sure it is on the RHS.
3040 std::swap(LHS, RHS);
3041 Pred = CmpInst::getSwappedPredicate(Pred);
3044 // Fold trivial predicates.
3045 if (Pred == FCmpInst::FCMP_FALSE)
3046 return ConstantInt::get(GetCompareTy(LHS), 0);
3047 if (Pred == FCmpInst::FCMP_TRUE)
3048 return ConstantInt::get(GetCompareTy(LHS), 1);
3050 if (isa<UndefValue>(RHS)) // fcmp pred X, undef -> undef
3051 return UndefValue::get(GetCompareTy(LHS));
3053 // fcmp x,x -> true/false. Not all compares are foldable.
3055 if (CmpInst::isTrueWhenEqual(Pred))
3056 return ConstantInt::get(GetCompareTy(LHS), 1);
3057 if (CmpInst::isFalseWhenEqual(Pred))
3058 return ConstantInt::get(GetCompareTy(LHS), 0);
3061 // Handle fcmp with constant RHS
3062 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
3063 // If the constant is a nan, see if we can fold the comparison based on it.
3064 if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHSC)) {
3065 if (CFP->getValueAPF().isNaN()) {
3066 if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo"
3067 return ConstantInt::getFalse(CFP->getContext());
3068 assert(FCmpInst::isUnordered(Pred) &&
3069 "Comparison must be either ordered or unordered!");
3070 // True if unordered.
3071 return ConstantInt::getTrue(CFP->getContext());
3073 // Check whether the constant is an infinity.
3074 if (CFP->getValueAPF().isInfinity()) {
3075 if (CFP->getValueAPF().isNegative()) {
3077 case FCmpInst::FCMP_OLT:
3078 // No value is ordered and less than negative infinity.
3079 return ConstantInt::getFalse(CFP->getContext());
3080 case FCmpInst::FCMP_UGE:
3081 // All values are unordered with or at least negative infinity.
3082 return ConstantInt::getTrue(CFP->getContext());
3088 case FCmpInst::FCMP_OGT:
3089 // No value is ordered and greater than infinity.
3090 return ConstantInt::getFalse(CFP->getContext());
3091 case FCmpInst::FCMP_ULE:
3092 // All values are unordered with and at most infinity.
3093 return ConstantInt::getTrue(CFP->getContext());
3102 // If the comparison is with the result of a select instruction, check whether
3103 // comparing with either branch of the select always yields the same value.
3104 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3105 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
3108 // If the comparison is with the result of a phi instruction, check whether
3109 // doing the compare with each incoming phi value yields a common result.
3110 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3111 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
3117 Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3118 const DataLayout *DL,
3119 const TargetLibraryInfo *TLI,
3120 const DominatorTree *DT,
3121 AssumptionTracker *AT,
3122 const Instruction *CxtI) {
3123 return ::SimplifyFCmpInst(Predicate, LHS, RHS, Query (DL, TLI, DT, AT, CxtI),
3127 /// SimplifySelectInst - Given operands for a SelectInst, see if we can fold
3128 /// the result. If not, this returns null.
3129 static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal,
3130 Value *FalseVal, const Query &Q,
3131 unsigned MaxRecurse) {
3132 // select true, X, Y -> X
3133 // select false, X, Y -> Y
3134 if (Constant *CB = dyn_cast<Constant>(CondVal)) {
3135 if (CB->isAllOnesValue())
3137 if (CB->isNullValue())
3141 // select C, X, X -> X
3142 if (TrueVal == FalseVal)
3145 if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y
3146 if (isa<Constant>(TrueVal))
3150 if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X
3152 if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
3155 const auto *ICI = dyn_cast<ICmpInst>(CondVal);
3156 unsigned BitWidth = TrueVal->getType()->getScalarSizeInBits();
3157 if (ICI && BitWidth) {
3158 ICmpInst::Predicate Pred = ICI->getPredicate();
3159 APInt MinSignedValue = APInt::getSignBit(BitWidth);
3163 bool IsBitTest = false;
3164 if (ICmpInst::isEquality(Pred) &&
3165 match(ICI->getOperand(0), m_And(m_Value(X), m_APInt(Y))) &&
3166 match(ICI->getOperand(1), m_Zero())) {
3168 TrueWhenUnset = Pred == ICmpInst::ICMP_EQ;
3169 } else if (Pred == ICmpInst::ICMP_SLT &&
3170 match(ICI->getOperand(1), m_Zero())) {
3171 X = ICI->getOperand(0);
3172 Y = &MinSignedValue;
3174 TrueWhenUnset = false;
3175 } else if (Pred == ICmpInst::ICMP_SGT &&
3176 match(ICI->getOperand(1), m_AllOnes())) {
3177 X = ICI->getOperand(0);
3178 Y = &MinSignedValue;
3180 TrueWhenUnset = true;
3184 // (X & Y) == 0 ? X & ~Y : X --> X
3185 // (X & Y) != 0 ? X & ~Y : X --> X & ~Y
3186 if (FalseVal == X && match(TrueVal, m_And(m_Specific(X), m_APInt(C))) &&
3188 return TrueWhenUnset ? FalseVal : TrueVal;
3189 // (X & Y) == 0 ? X : X & ~Y --> X & ~Y
3190 // (X & Y) != 0 ? X : X & ~Y --> X
3191 if (TrueVal == X && match(FalseVal, m_And(m_Specific(X), m_APInt(C))) &&
3193 return TrueWhenUnset ? FalseVal : TrueVal;
3195 if (Y->isPowerOf2()) {
3196 // (X & Y) == 0 ? X | Y : X --> X | Y
3197 // (X & Y) != 0 ? X | Y : X --> X
3198 if (FalseVal == X && match(TrueVal, m_Or(m_Specific(X), m_APInt(C))) &&
3200 return TrueWhenUnset ? TrueVal : FalseVal;
3201 // (X & Y) == 0 ? X : X | Y --> X
3202 // (X & Y) != 0 ? X : X | Y --> X | Y
3203 if (TrueVal == X && match(FalseVal, m_Or(m_Specific(X), m_APInt(C))) &&
3205 return TrueWhenUnset ? TrueVal : FalseVal;
3213 Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
3214 const DataLayout *DL,
3215 const TargetLibraryInfo *TLI,
3216 const DominatorTree *DT,
3217 AssumptionTracker *AT,
3218 const Instruction *CxtI) {
3219 return ::SimplifySelectInst(Cond, TrueVal, FalseVal,
3220 Query (DL, TLI, DT, AT, CxtI), RecursionLimit);
3223 /// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
3224 /// fold the result. If not, this returns null.
3225 static Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const Query &Q, unsigned) {
3226 // The type of the GEP pointer operand.
3227 PointerType *PtrTy = cast<PointerType>(Ops[0]->getType()->getScalarType());
3228 unsigned AS = PtrTy->getAddressSpace();
3230 // getelementptr P -> P.
3231 if (Ops.size() == 1)
3234 // Compute the (pointer) type returned by the GEP instruction.
3235 Type *LastType = GetElementPtrInst::getIndexedType(PtrTy, Ops.slice(1));
3236 Type *GEPTy = PointerType::get(LastType, AS);
3237 if (VectorType *VT = dyn_cast<VectorType>(Ops[0]->getType()))
3238 GEPTy = VectorType::get(GEPTy, VT->getNumElements());
3240 if (isa<UndefValue>(Ops[0]))
3241 return UndefValue::get(GEPTy);
3243 if (Ops.size() == 2) {
3244 // getelementptr P, 0 -> P.
3245 if (match(Ops[1], m_Zero()))
3248 Type *Ty = PtrTy->getElementType();
3249 if (Q.DL && Ty->isSized()) {
3252 uint64_t TyAllocSize = Q.DL->getTypeAllocSize(Ty);
3253 // getelementptr P, N -> P if P points to a type of zero size.
3254 if (TyAllocSize == 0)
3257 // The following transforms are only safe if the ptrtoint cast
3258 // doesn't truncate the pointers.
3259 if (Ops[1]->getType()->getScalarSizeInBits() ==
3260 Q.DL->getPointerSizeInBits(AS)) {
3261 auto PtrToIntOrZero = [GEPTy](Value *P) -> Value * {
3262 if (match(P, m_Zero()))
3263 return Constant::getNullValue(GEPTy);
3265 if (match(P, m_PtrToInt(m_Value(Temp))))
3266 if (Temp->getType() == GEPTy)
3271 // getelementptr V, (sub P, V) -> P if P points to a type of size 1.
3272 if (TyAllocSize == 1 &&
3273 match(Ops[1], m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0])))))
3274 if (Value *R = PtrToIntOrZero(P))
3277 // getelementptr V, (ashr (sub P, V), C) -> Q
3278 // if P points to a type of size 1 << C.
3280 m_AShr(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3281 m_ConstantInt(C))) &&
3282 TyAllocSize == 1ULL << C)
3283 if (Value *R = PtrToIntOrZero(P))
3286 // getelementptr V, (sdiv (sub P, V), C) -> Q
3287 // if P points to a type of size C.
3289 m_SDiv(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3290 m_SpecificInt(TyAllocSize))))
3291 if (Value *R = PtrToIntOrZero(P))
3297 // Check to see if this is constant foldable.
3298 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
3299 if (!isa<Constant>(Ops[i]))
3302 return ConstantExpr::getGetElementPtr(cast<Constant>(Ops[0]), Ops.slice(1));
3305 Value *llvm::SimplifyGEPInst(ArrayRef<Value *> Ops, const DataLayout *DL,
3306 const TargetLibraryInfo *TLI,
3307 const DominatorTree *DT, AssumptionTracker *AT,
3308 const Instruction *CxtI) {
3309 return ::SimplifyGEPInst(Ops, Query (DL, TLI, DT, AT, CxtI), RecursionLimit);
3312 /// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we
3313 /// can fold the result. If not, this returns null.
3314 static Value *SimplifyInsertValueInst(Value *Agg, Value *Val,
3315 ArrayRef<unsigned> Idxs, const Query &Q,
3317 if (Constant *CAgg = dyn_cast<Constant>(Agg))
3318 if (Constant *CVal = dyn_cast<Constant>(Val))
3319 return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
3321 // insertvalue x, undef, n -> x
3322 if (match(Val, m_Undef()))
3325 // insertvalue x, (extractvalue y, n), n
3326 if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
3327 if (EV->getAggregateOperand()->getType() == Agg->getType() &&
3328 EV->getIndices() == Idxs) {
3329 // insertvalue undef, (extractvalue y, n), n -> y
3330 if (match(Agg, m_Undef()))
3331 return EV->getAggregateOperand();
3333 // insertvalue y, (extractvalue y, n), n -> y
3334 if (Agg == EV->getAggregateOperand())
3341 Value *llvm::SimplifyInsertValueInst(Value *Agg, Value *Val,
3342 ArrayRef<unsigned> Idxs,
3343 const DataLayout *DL,
3344 const TargetLibraryInfo *TLI,
3345 const DominatorTree *DT,
3346 AssumptionTracker *AT,
3347 const Instruction *CxtI) {
3348 return ::SimplifyInsertValueInst(Agg, Val, Idxs,
3349 Query (DL, TLI, DT, AT, 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,
3397 AssumptionTracker *AT,
3398 const Instruction *CxtI) {
3399 return ::SimplifyTruncInst(Op, Ty, Query (DL, TLI, DT, AT, CxtI),
3403 //=== Helper functions for higher up the class hierarchy.
3405 /// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
3406 /// fold the result. If not, this returns null.
3407 static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
3408 const Query &Q, unsigned MaxRecurse) {
3410 case Instruction::Add:
3411 return SimplifyAddInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
3413 case Instruction::FAdd:
3414 return SimplifyFAddInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3416 case Instruction::Sub:
3417 return SimplifySubInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
3419 case Instruction::FSub:
3420 return SimplifyFSubInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3422 case Instruction::Mul: return SimplifyMulInst (LHS, RHS, Q, MaxRecurse);
3423 case Instruction::FMul:
3424 return SimplifyFMulInst (LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3425 case Instruction::SDiv: return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
3426 case Instruction::UDiv: return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
3427 case Instruction::FDiv: return SimplifyFDivInst(LHS, RHS, Q, MaxRecurse);
3428 case Instruction::SRem: return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
3429 case Instruction::URem: return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
3430 case Instruction::FRem: return SimplifyFRemInst(LHS, RHS, Q, MaxRecurse);
3431 case Instruction::Shl:
3432 return SimplifyShlInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
3434 case Instruction::LShr:
3435 return SimplifyLShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
3436 case Instruction::AShr:
3437 return SimplifyAShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
3438 case Instruction::And: return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
3439 case Instruction::Or: return SimplifyOrInst (LHS, RHS, Q, MaxRecurse);
3440 case Instruction::Xor: return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
3442 if (Constant *CLHS = dyn_cast<Constant>(LHS))
3443 if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
3444 Constant *COps[] = {CLHS, CRHS};
3445 return ConstantFoldInstOperands(Opcode, LHS->getType(), COps, Q.DL,
3449 // If the operation is associative, try some generic simplifications.
3450 if (Instruction::isAssociative(Opcode))
3451 if (Value *V = SimplifyAssociativeBinOp(Opcode, LHS, RHS, Q, MaxRecurse))
3454 // If the operation is with the result of a select instruction check whether
3455 // operating on either branch of the select always yields the same value.
3456 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3457 if (Value *V = ThreadBinOpOverSelect(Opcode, LHS, RHS, Q, MaxRecurse))
3460 // If the operation is with the result of a phi instruction, check whether
3461 // operating on all incoming values of the phi always yields the same value.
3462 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3463 if (Value *V = ThreadBinOpOverPHI(Opcode, LHS, RHS, Q, MaxRecurse))
3470 Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
3471 const DataLayout *DL, const TargetLibraryInfo *TLI,
3472 const DominatorTree *DT, AssumptionTracker *AT,
3473 const Instruction *CxtI) {
3474 return ::SimplifyBinOp(Opcode, LHS, RHS, Query (DL, TLI, DT, AT, CxtI),
3478 /// SimplifyCmpInst - Given operands for a CmpInst, see if we can
3479 /// fold the result.
3480 static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3481 const Query &Q, unsigned MaxRecurse) {
3482 if (CmpInst::isIntPredicate((CmpInst::Predicate)Predicate))
3483 return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
3484 return SimplifyFCmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
3487 Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3488 const DataLayout *DL, const TargetLibraryInfo *TLI,
3489 const DominatorTree *DT, AssumptionTracker *AT,
3490 const Instruction *CxtI) {
3491 return ::SimplifyCmpInst(Predicate, LHS, RHS, Query (DL, TLI, DT, AT, CxtI),
3495 static bool IsIdempotent(Intrinsic::ID ID) {
3497 default: return false;
3499 // Unary idempotent: f(f(x)) = f(x)
3500 case Intrinsic::fabs:
3501 case Intrinsic::floor:
3502 case Intrinsic::ceil:
3503 case Intrinsic::trunc:
3504 case Intrinsic::rint:
3505 case Intrinsic::nearbyint:
3506 case Intrinsic::round:
3511 template <typename IterTy>
3512 static Value *SimplifyIntrinsic(Intrinsic::ID IID, IterTy ArgBegin, IterTy ArgEnd,
3513 const Query &Q, unsigned MaxRecurse) {
3514 // Perform idempotent optimizations
3515 if (!IsIdempotent(IID))
3519 if (std::distance(ArgBegin, ArgEnd) == 1)
3520 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(*ArgBegin))
3521 if (II->getIntrinsicID() == IID)
3527 template <typename IterTy>
3528 static Value *SimplifyCall(Value *V, IterTy ArgBegin, IterTy ArgEnd,
3529 const Query &Q, unsigned MaxRecurse) {
3530 Type *Ty = V->getType();
3531 if (PointerType *PTy = dyn_cast<PointerType>(Ty))
3532 Ty = PTy->getElementType();
3533 FunctionType *FTy = cast<FunctionType>(Ty);
3535 // call undef -> undef
3536 if (isa<UndefValue>(V))
3537 return UndefValue::get(FTy->getReturnType());
3539 Function *F = dyn_cast<Function>(V);
3543 if (unsigned IID = F->getIntrinsicID())
3545 SimplifyIntrinsic((Intrinsic::ID) IID, ArgBegin, ArgEnd, Q, MaxRecurse))
3548 if (!canConstantFoldCallTo(F))
3551 SmallVector<Constant *, 4> ConstantArgs;
3552 ConstantArgs.reserve(ArgEnd - ArgBegin);
3553 for (IterTy I = ArgBegin, E = ArgEnd; I != E; ++I) {
3554 Constant *C = dyn_cast<Constant>(*I);
3557 ConstantArgs.push_back(C);
3560 return ConstantFoldCall(F, ConstantArgs, Q.TLI);
3563 Value *llvm::SimplifyCall(Value *V, User::op_iterator ArgBegin,
3564 User::op_iterator ArgEnd, const DataLayout *DL,
3565 const TargetLibraryInfo *TLI,
3566 const DominatorTree *DT, AssumptionTracker *AT,
3567 const Instruction *CxtI) {
3568 return ::SimplifyCall(V, ArgBegin, ArgEnd, Query(DL, TLI, DT, AT, CxtI),
3572 Value *llvm::SimplifyCall(Value *V, ArrayRef<Value *> Args,
3573 const DataLayout *DL, const TargetLibraryInfo *TLI,
3574 const DominatorTree *DT, AssumptionTracker *AT,
3575 const Instruction *CxtI) {
3576 return ::SimplifyCall(V, Args.begin(), Args.end(),
3577 Query(DL, TLI, DT, AT, CxtI), RecursionLimit);
3580 /// SimplifyInstruction - See if we can compute a simplified version of this
3581 /// instruction. If not, this returns null.
3582 Value *llvm::SimplifyInstruction(Instruction *I, const DataLayout *DL,
3583 const TargetLibraryInfo *TLI,
3584 const DominatorTree *DT,
3585 AssumptionTracker *AT) {
3588 switch (I->getOpcode()) {
3590 Result = ConstantFoldInstruction(I, DL, TLI);
3592 case Instruction::FAdd:
3593 Result = SimplifyFAddInst(I->getOperand(0), I->getOperand(1),
3594 I->getFastMathFlags(), DL, TLI, DT, AT, I);
3596 case Instruction::Add:
3597 Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
3598 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3599 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3600 DL, TLI, DT, AT, I);
3602 case Instruction::FSub:
3603 Result = SimplifyFSubInst(I->getOperand(0), I->getOperand(1),
3604 I->getFastMathFlags(), DL, TLI, DT, AT, I);
3606 case Instruction::Sub:
3607 Result = SimplifySubInst(I->getOperand(0), I->getOperand(1),
3608 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3609 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3610 DL, TLI, DT, AT, I);
3612 case Instruction::FMul:
3613 Result = SimplifyFMulInst(I->getOperand(0), I->getOperand(1),
3614 I->getFastMathFlags(), DL, TLI, DT, AT, I);
3616 case Instruction::Mul:
3617 Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1),
3618 DL, TLI, DT, AT, I);
3620 case Instruction::SDiv:
3621 Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1),
3622 DL, TLI, DT, AT, I);
3624 case Instruction::UDiv:
3625 Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1),
3626 DL, TLI, DT, AT, I);
3628 case Instruction::FDiv:
3629 Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1),
3630 DL, TLI, DT, AT, I);
3632 case Instruction::SRem:
3633 Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1),
3634 DL, TLI, DT, AT, I);
3636 case Instruction::URem:
3637 Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1),
3638 DL, TLI, DT, AT, I);
3640 case Instruction::FRem:
3641 Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1),
3642 DL, TLI, DT, AT, I);
3644 case Instruction::Shl:
3645 Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1),
3646 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3647 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3648 DL, TLI, DT, AT, I);
3650 case Instruction::LShr:
3651 Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
3652 cast<BinaryOperator>(I)->isExact(),
3653 DL, TLI, DT, AT, I);
3655 case Instruction::AShr:
3656 Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
3657 cast<BinaryOperator>(I)->isExact(),
3658 DL, TLI, DT, AT, I);
3660 case Instruction::And:
3661 Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1),
3662 DL, TLI, DT, AT, I);
3664 case Instruction::Or:
3665 Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT,
3668 case Instruction::Xor:
3669 Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1),
3670 DL, TLI, DT, AT, I);
3672 case Instruction::ICmp:
3673 Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
3674 I->getOperand(0), I->getOperand(1),
3675 DL, TLI, DT, AT, I);
3677 case Instruction::FCmp:
3678 Result = SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(),
3679 I->getOperand(0), I->getOperand(1),
3680 DL, TLI, DT, AT, I);
3682 case Instruction::Select:
3683 Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
3684 I->getOperand(2), DL, TLI, DT, AT, I);
3686 case Instruction::GetElementPtr: {
3687 SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end());
3688 Result = SimplifyGEPInst(Ops, DL, TLI, DT, AT, I);
3691 case Instruction::InsertValue: {
3692 InsertValueInst *IV = cast<InsertValueInst>(I);
3693 Result = SimplifyInsertValueInst(IV->getAggregateOperand(),
3694 IV->getInsertedValueOperand(),
3695 IV->getIndices(), DL, TLI, DT, AT, I);
3698 case Instruction::PHI:
3699 Result = SimplifyPHINode(cast<PHINode>(I), Query (DL, TLI, DT, AT, I));
3701 case Instruction::Call: {
3702 CallSite CS(cast<CallInst>(I));
3703 Result = SimplifyCall(CS.getCalledValue(), CS.arg_begin(), CS.arg_end(),
3704 DL, TLI, DT, AT, I);
3707 case Instruction::Trunc:
3708 Result = SimplifyTruncInst(I->getOperand(0), I->getType(), DL, TLI, DT,
3713 /// If called on unreachable code, the above logic may report that the
3714 /// instruction simplified to itself. Make life easier for users by
3715 /// detecting that case here, returning a safe value instead.
3716 return Result == I ? UndefValue::get(I->getType()) : Result;
3719 /// \brief Implementation of recursive simplification through an instructions
3722 /// This is the common implementation of the recursive simplification routines.
3723 /// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
3724 /// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
3725 /// instructions to process and attempt to simplify it using
3726 /// InstructionSimplify.
3728 /// This routine returns 'true' only when *it* simplifies something. The passed
3729 /// in simplified value does not count toward this.
3730 static bool replaceAndRecursivelySimplifyImpl(Instruction *I, Value *SimpleV,
3731 const DataLayout *DL,
3732 const TargetLibraryInfo *TLI,
3733 const DominatorTree *DT,
3734 AssumptionTracker *AT) {
3735 bool Simplified = false;
3736 SmallSetVector<Instruction *, 8> Worklist;
3738 // If we have an explicit value to collapse to, do that round of the
3739 // simplification loop by hand initially.
3741 for (User *U : I->users())
3743 Worklist.insert(cast<Instruction>(U));
3745 // Replace the instruction with its simplified value.
3746 I->replaceAllUsesWith(SimpleV);
3748 // Gracefully handle edge cases where the instruction is not wired into any
3751 I->eraseFromParent();
3756 // Note that we must test the size on each iteration, the worklist can grow.
3757 for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
3760 // See if this instruction simplifies.
3761 SimpleV = SimplifyInstruction(I, DL, TLI, DT, AT);
3767 // Stash away all the uses of the old instruction so we can check them for
3768 // recursive simplifications after a RAUW. This is cheaper than checking all
3769 // uses of To on the recursive step in most cases.
3770 for (User *U : I->users())
3771 Worklist.insert(cast<Instruction>(U));
3773 // Replace the instruction with its simplified value.
3774 I->replaceAllUsesWith(SimpleV);
3776 // Gracefully handle edge cases where the instruction is not wired into any
3779 I->eraseFromParent();
3784 bool llvm::recursivelySimplifyInstruction(Instruction *I,
3785 const DataLayout *DL,
3786 const TargetLibraryInfo *TLI,
3787 const DominatorTree *DT,
3788 AssumptionTracker *AT) {
3789 return replaceAndRecursivelySimplifyImpl(I, nullptr, DL, TLI, DT, AT);
3792 bool llvm::replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV,
3793 const DataLayout *DL,
3794 const TargetLibraryInfo *TLI,
3795 const DominatorTree *DT,
3796 AssumptionTracker *AT) {
3797 assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!");
3798 assert(SimpleV && "Must provide a simplified value.");
3799 return replaceAndRecursivelySimplifyImpl(I, SimpleV, DL, TLI, DT, AT);