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());
1341 // The low bit cannot be shifted out of an exact shift if it is set.
1343 unsigned BitWidth = Op0->getType()->getScalarSizeInBits();
1344 APInt Op0KnownZero(BitWidth, 0);
1345 APInt Op0KnownOne(BitWidth, 0);
1346 computeKnownBits(Op0, Op0KnownZero, Op0KnownOne, Q.DL, /*Depth=*/0, Q.AT, Q.CxtI,
1355 /// SimplifyShlInst - Given operands for an Shl, see if we can
1356 /// fold the result. If not, this returns null.
1357 static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1358 const Query &Q, unsigned MaxRecurse) {
1359 if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse))
1363 if (match(Op0, m_Undef()))
1364 return Constant::getNullValue(Op0->getType());
1366 // (X >> A) << A -> X
1368 if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
1373 Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1374 const DataLayout *DL, const TargetLibraryInfo *TLI,
1375 const DominatorTree *DT, AssumptionTracker *AT,
1376 const Instruction *CxtI) {
1377 return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Query (DL, TLI, DT, AT, CxtI),
1381 /// SimplifyLShrInst - Given operands for an LShr, see if we can
1382 /// fold the result. If not, this returns null.
1383 static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1384 const Query &Q, unsigned MaxRecurse) {
1385 if (Value *V = SimplifyRightShift(Instruction::LShr, Op0, Op1, isExact, Q,
1390 if (match(Op0, m_Undef()))
1391 return Constant::getNullValue(Op0->getType());
1393 // (X << A) >> A -> X
1395 if (match(Op0, m_NUWShl(m_Value(X), m_Specific(Op1))))
1401 Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1402 const DataLayout *DL,
1403 const TargetLibraryInfo *TLI,
1404 const DominatorTree *DT,
1405 AssumptionTracker *AT,
1406 const Instruction *CxtI) {
1407 return ::SimplifyLShrInst(Op0, Op1, isExact, Query (DL, TLI, DT, AT, CxtI),
1411 /// SimplifyAShrInst - Given operands for an AShr, see if we can
1412 /// fold the result. If not, this returns null.
1413 static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1414 const Query &Q, unsigned MaxRecurse) {
1415 if (Value *V = SimplifyRightShift(Instruction::AShr, Op0, Op1, isExact, Q,
1419 // all ones >>a X -> all ones
1420 if (match(Op0, m_AllOnes()))
1423 // undef >>a X -> all ones
1424 if (match(Op0, m_Undef()))
1425 return Constant::getAllOnesValue(Op0->getType());
1427 // (X << A) >> A -> X
1429 if (match(Op0, m_NSWShl(m_Value(X), m_Specific(Op1))))
1432 // Arithmetic shifting an all-sign-bit value is a no-op.
1433 unsigned NumSignBits = ComputeNumSignBits(Op0, Q.DL, 0, Q.AT, Q.CxtI, Q.DT);
1434 if (NumSignBits == Op0->getType()->getScalarSizeInBits())
1440 Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1441 const DataLayout *DL,
1442 const TargetLibraryInfo *TLI,
1443 const DominatorTree *DT,
1444 AssumptionTracker *AT,
1445 const Instruction *CxtI) {
1446 return ::SimplifyAShrInst(Op0, Op1, isExact, Query (DL, TLI, DT, AT, CxtI),
1450 static Value *simplifyUnsignedRangeCheck(ICmpInst *ZeroICmp,
1451 ICmpInst *UnsignedICmp, bool IsAnd) {
1454 ICmpInst::Predicate EqPred;
1455 if (!match(ZeroICmp, m_ICmp(EqPred, m_Value(Y), m_Zero())) ||
1456 !ICmpInst::isEquality(EqPred))
1459 ICmpInst::Predicate UnsignedPred;
1460 if (match(UnsignedICmp, m_ICmp(UnsignedPred, m_Value(X), m_Specific(Y))) &&
1461 ICmpInst::isUnsigned(UnsignedPred))
1463 else if (match(UnsignedICmp,
1464 m_ICmp(UnsignedPred, m_Value(Y), m_Specific(X))) &&
1465 ICmpInst::isUnsigned(UnsignedPred))
1466 UnsignedPred = ICmpInst::getSwappedPredicate(UnsignedPred);
1470 // X < Y && Y != 0 --> X < Y
1471 // X < Y || Y != 0 --> Y != 0
1472 if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_NE)
1473 return IsAnd ? UnsignedICmp : ZeroICmp;
1475 // X >= Y || Y != 0 --> true
1476 // X >= Y || Y == 0 --> X >= Y
1477 if (UnsignedPred == ICmpInst::ICMP_UGE && !IsAnd) {
1478 if (EqPred == ICmpInst::ICMP_NE)
1479 return getTrue(UnsignedICmp->getType());
1480 return UnsignedICmp;
1483 // X < Y && Y == 0 --> false
1484 if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_EQ &&
1486 return getFalse(UnsignedICmp->getType());
1491 // Simplify (and (icmp ...) (icmp ...)) to true when we can tell that the range
1492 // of possible values cannot be satisfied.
1493 static Value *SimplifyAndOfICmps(ICmpInst *Op0, ICmpInst *Op1) {
1494 ICmpInst::Predicate Pred0, Pred1;
1495 ConstantInt *CI1, *CI2;
1498 if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/true))
1501 if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_ConstantInt(CI1)),
1502 m_ConstantInt(CI2))))
1505 if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Specific(CI1))))
1508 Type *ITy = Op0->getType();
1510 auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1511 bool isNSW = AddInst->hasNoSignedWrap();
1512 bool isNUW = AddInst->hasNoUnsignedWrap();
1514 const APInt &CI1V = CI1->getValue();
1515 const APInt &CI2V = CI2->getValue();
1516 const APInt Delta = CI2V - CI1V;
1517 if (CI1V.isStrictlyPositive()) {
1519 if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_SGT)
1520 return getFalse(ITy);
1521 if (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1522 return getFalse(ITy);
1525 if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_SGT)
1526 return getFalse(ITy);
1527 if (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1528 return getFalse(ITy);
1531 if (CI1V.getBoolValue() && isNUW) {
1533 if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT)
1534 return getFalse(ITy);
1536 if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGT)
1537 return getFalse(ITy);
1543 /// SimplifyAndInst - Given operands for an And, see if we can
1544 /// fold the result. If not, this returns null.
1545 static Value *SimplifyAndInst(Value *Op0, Value *Op1, const Query &Q,
1546 unsigned MaxRecurse) {
1547 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1548 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1549 Constant *Ops[] = { CLHS, CRHS };
1550 return ConstantFoldInstOperands(Instruction::And, CLHS->getType(),
1554 // Canonicalize the constant to the RHS.
1555 std::swap(Op0, Op1);
1559 if (match(Op1, m_Undef()))
1560 return Constant::getNullValue(Op0->getType());
1567 if (match(Op1, m_Zero()))
1571 if (match(Op1, m_AllOnes()))
1574 // A & ~A = ~A & A = 0
1575 if (match(Op0, m_Not(m_Specific(Op1))) ||
1576 match(Op1, m_Not(m_Specific(Op0))))
1577 return Constant::getNullValue(Op0->getType());
1580 Value *A = nullptr, *B = nullptr;
1581 if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
1582 (A == Op1 || B == Op1))
1586 if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
1587 (A == Op0 || B == Op0))
1590 // A & (-A) = A if A is a power of two or zero.
1591 if (match(Op0, m_Neg(m_Specific(Op1))) ||
1592 match(Op1, m_Neg(m_Specific(Op0)))) {
1593 if (isKnownToBeAPowerOfTwo(Op0, /*OrZero*/true, 0, Q.AT, Q.CxtI, Q.DT))
1595 if (isKnownToBeAPowerOfTwo(Op1, /*OrZero*/true, 0, Q.AT, Q.CxtI, Q.DT))
1599 if (auto *ICILHS = dyn_cast<ICmpInst>(Op0)) {
1600 if (auto *ICIRHS = dyn_cast<ICmpInst>(Op1)) {
1601 if (Value *V = SimplifyAndOfICmps(ICILHS, ICIRHS))
1603 if (Value *V = SimplifyAndOfICmps(ICIRHS, ICILHS))
1608 // Try some generic simplifications for associative operations.
1609 if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
1613 // And distributes over Or. Try some generic simplifications based on this.
1614 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1618 // And distributes over Xor. Try some generic simplifications based on this.
1619 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
1623 // If the operation is with the result of a select instruction, check whether
1624 // operating on either branch of the select always yields the same value.
1625 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1626 if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
1630 // If the operation is with the result of a phi instruction, check whether
1631 // operating on all incoming values of the phi always yields the same value.
1632 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1633 if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
1640 Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const DataLayout *DL,
1641 const TargetLibraryInfo *TLI,
1642 const DominatorTree *DT, AssumptionTracker *AT,
1643 const Instruction *CxtI) {
1644 return ::SimplifyAndInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1648 // Simplify (or (icmp ...) (icmp ...)) to true when we can tell that the union
1649 // contains all possible values.
1650 static Value *SimplifyOrOfICmps(ICmpInst *Op0, ICmpInst *Op1) {
1651 ICmpInst::Predicate Pred0, Pred1;
1652 ConstantInt *CI1, *CI2;
1655 if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/false))
1658 if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_ConstantInt(CI1)),
1659 m_ConstantInt(CI2))))
1662 if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Specific(CI1))))
1665 Type *ITy = Op0->getType();
1667 auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1668 bool isNSW = AddInst->hasNoSignedWrap();
1669 bool isNUW = AddInst->hasNoUnsignedWrap();
1671 const APInt &CI1V = CI1->getValue();
1672 const APInt &CI2V = CI2->getValue();
1673 const APInt Delta = CI2V - CI1V;
1674 if (CI1V.isStrictlyPositive()) {
1676 if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_SLE)
1677 return getTrue(ITy);
1678 if (Pred0 == ICmpInst::ICMP_SGE && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1679 return getTrue(ITy);
1682 if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_SLE)
1683 return getTrue(ITy);
1684 if (Pred0 == ICmpInst::ICMP_SGT && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1685 return getTrue(ITy);
1688 if (CI1V.getBoolValue() && isNUW) {
1690 if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_ULE)
1691 return getTrue(ITy);
1693 if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_ULE)
1694 return getTrue(ITy);
1700 /// SimplifyOrInst - Given operands for an Or, see if we can
1701 /// fold the result. If not, this returns null.
1702 static Value *SimplifyOrInst(Value *Op0, Value *Op1, const Query &Q,
1703 unsigned MaxRecurse) {
1704 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1705 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1706 Constant *Ops[] = { CLHS, CRHS };
1707 return ConstantFoldInstOperands(Instruction::Or, CLHS->getType(),
1711 // Canonicalize the constant to the RHS.
1712 std::swap(Op0, Op1);
1716 if (match(Op1, m_Undef()))
1717 return Constant::getAllOnesValue(Op0->getType());
1724 if (match(Op1, m_Zero()))
1728 if (match(Op1, m_AllOnes()))
1731 // A | ~A = ~A | A = -1
1732 if (match(Op0, m_Not(m_Specific(Op1))) ||
1733 match(Op1, m_Not(m_Specific(Op0))))
1734 return Constant::getAllOnesValue(Op0->getType());
1737 Value *A = nullptr, *B = nullptr;
1738 if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
1739 (A == Op1 || B == Op1))
1743 if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
1744 (A == Op0 || B == Op0))
1747 // ~(A & ?) | A = -1
1748 if (match(Op0, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1749 (A == Op1 || B == Op1))
1750 return Constant::getAllOnesValue(Op1->getType());
1752 // A | ~(A & ?) = -1
1753 if (match(Op1, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1754 (A == Op0 || B == Op0))
1755 return Constant::getAllOnesValue(Op0->getType());
1757 if (auto *ICILHS = dyn_cast<ICmpInst>(Op0)) {
1758 if (auto *ICIRHS = dyn_cast<ICmpInst>(Op1)) {
1759 if (Value *V = SimplifyOrOfICmps(ICILHS, ICIRHS))
1761 if (Value *V = SimplifyOrOfICmps(ICIRHS, ICILHS))
1766 // Try some generic simplifications for associative operations.
1767 if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
1771 // Or distributes over And. Try some generic simplifications based on this.
1772 if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
1776 // If the operation is with the result of a select instruction, check whether
1777 // operating on either branch of the select always yields the same value.
1778 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1779 if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
1784 Value *C = nullptr, *D = nullptr;
1785 if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
1786 match(Op1, m_And(m_Value(B), m_Value(D)))) {
1787 ConstantInt *C1 = dyn_cast<ConstantInt>(C);
1788 ConstantInt *C2 = dyn_cast<ConstantInt>(D);
1789 if (C1 && C2 && (C1->getValue() == ~C2->getValue())) {
1790 // (A & C1)|(B & C2)
1791 // If we have: ((V + N) & C1) | (V & C2)
1792 // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
1793 // replace with V+N.
1795 if ((C2->getValue() & (C2->getValue() + 1)) == 0 && // C2 == 0+1+
1796 match(A, m_Add(m_Value(V1), m_Value(V2)))) {
1797 // Add commutes, try both ways.
1798 if (V1 == B && MaskedValueIsZero(V2, C2->getValue(), Q.DL,
1799 0, Q.AT, Q.CxtI, Q.DT))
1801 if (V2 == B && MaskedValueIsZero(V1, C2->getValue(), Q.DL,
1802 0, Q.AT, Q.CxtI, Q.DT))
1805 // Or commutes, try both ways.
1806 if ((C1->getValue() & (C1->getValue() + 1)) == 0 &&
1807 match(B, m_Add(m_Value(V1), m_Value(V2)))) {
1808 // Add commutes, try both ways.
1809 if (V1 == A && MaskedValueIsZero(V2, C1->getValue(), Q.DL,
1810 0, Q.AT, Q.CxtI, Q.DT))
1812 if (V2 == A && MaskedValueIsZero(V1, C1->getValue(), Q.DL,
1813 0, Q.AT, Q.CxtI, Q.DT))
1819 // If the operation is with the result of a phi instruction, check whether
1820 // operating on all incoming values of the phi always yields the same value.
1821 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1822 if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
1828 Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const DataLayout *DL,
1829 const TargetLibraryInfo *TLI,
1830 const DominatorTree *DT, AssumptionTracker *AT,
1831 const Instruction *CxtI) {
1832 return ::SimplifyOrInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1836 /// SimplifyXorInst - Given operands for a Xor, see if we can
1837 /// fold the result. If not, this returns null.
1838 static Value *SimplifyXorInst(Value *Op0, Value *Op1, const Query &Q,
1839 unsigned MaxRecurse) {
1840 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1841 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1842 Constant *Ops[] = { CLHS, CRHS };
1843 return ConstantFoldInstOperands(Instruction::Xor, CLHS->getType(),
1847 // Canonicalize the constant to the RHS.
1848 std::swap(Op0, Op1);
1851 // A ^ undef -> undef
1852 if (match(Op1, m_Undef()))
1856 if (match(Op1, m_Zero()))
1861 return Constant::getNullValue(Op0->getType());
1863 // A ^ ~A = ~A ^ A = -1
1864 if (match(Op0, m_Not(m_Specific(Op1))) ||
1865 match(Op1, m_Not(m_Specific(Op0))))
1866 return Constant::getAllOnesValue(Op0->getType());
1868 // Try some generic simplifications for associative operations.
1869 if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
1873 // Threading Xor over selects and phi nodes is pointless, so don't bother.
1874 // Threading over the select in "A ^ select(cond, B, C)" means evaluating
1875 // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
1876 // only if B and C are equal. If B and C are equal then (since we assume
1877 // that operands have already been simplified) "select(cond, B, C)" should
1878 // have been simplified to the common value of B and C already. Analysing
1879 // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
1880 // for threading over phi nodes.
1885 Value *llvm::SimplifyXorInst(Value *Op0, Value *Op1, const DataLayout *DL,
1886 const TargetLibraryInfo *TLI,
1887 const DominatorTree *DT, AssumptionTracker *AT,
1888 const Instruction *CxtI) {
1889 return ::SimplifyXorInst(Op0, Op1, Query (DL, TLI, DT, AT, CxtI),
1893 static Type *GetCompareTy(Value *Op) {
1894 return CmpInst::makeCmpResultType(Op->getType());
1897 /// ExtractEquivalentCondition - Rummage around inside V looking for something
1898 /// equivalent to the comparison "LHS Pred RHS". Return such a value if found,
1899 /// otherwise return null. Helper function for analyzing max/min idioms.
1900 static Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred,
1901 Value *LHS, Value *RHS) {
1902 SelectInst *SI = dyn_cast<SelectInst>(V);
1905 CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
1908 Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
1909 if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
1911 if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
1912 LHS == CmpRHS && RHS == CmpLHS)
1917 // A significant optimization not implemented here is assuming that alloca
1918 // addresses are not equal to incoming argument values. They don't *alias*,
1919 // as we say, but that doesn't mean they aren't equal, so we take a
1920 // conservative approach.
1922 // This is inspired in part by C++11 5.10p1:
1923 // "Two pointers of the same type compare equal if and only if they are both
1924 // null, both point to the same function, or both represent the same
1927 // This is pretty permissive.
1929 // It's also partly due to C11 6.5.9p6:
1930 // "Two pointers compare equal if and only if both are null pointers, both are
1931 // pointers to the same object (including a pointer to an object and a
1932 // subobject at its beginning) or function, both are pointers to one past the
1933 // last element of the same array object, or one is a pointer to one past the
1934 // end of one array object and the other is a pointer to the start of a
1935 // different array object that happens to immediately follow the first array
1936 // object in the address space.)
1938 // C11's version is more restrictive, however there's no reason why an argument
1939 // couldn't be a one-past-the-end value for a stack object in the caller and be
1940 // equal to the beginning of a stack object in the callee.
1942 // If the C and C++ standards are ever made sufficiently restrictive in this
1943 // area, it may be possible to update LLVM's semantics accordingly and reinstate
1944 // this optimization.
1945 static Constant *computePointerICmp(const DataLayout *DL,
1946 const TargetLibraryInfo *TLI,
1947 CmpInst::Predicate Pred,
1948 Value *LHS, Value *RHS) {
1949 // First, skip past any trivial no-ops.
1950 LHS = LHS->stripPointerCasts();
1951 RHS = RHS->stripPointerCasts();
1953 // A non-null pointer is not equal to a null pointer.
1954 if (llvm::isKnownNonNull(LHS, TLI) && isa<ConstantPointerNull>(RHS) &&
1955 (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE))
1956 return ConstantInt::get(GetCompareTy(LHS),
1957 !CmpInst::isTrueWhenEqual(Pred));
1959 // We can only fold certain predicates on pointer comparisons.
1964 // Equality comaprisons are easy to fold.
1965 case CmpInst::ICMP_EQ:
1966 case CmpInst::ICMP_NE:
1969 // We can only handle unsigned relational comparisons because 'inbounds' on
1970 // a GEP only protects against unsigned wrapping.
1971 case CmpInst::ICMP_UGT:
1972 case CmpInst::ICMP_UGE:
1973 case CmpInst::ICMP_ULT:
1974 case CmpInst::ICMP_ULE:
1975 // However, we have to switch them to their signed variants to handle
1976 // negative indices from the base pointer.
1977 Pred = ICmpInst::getSignedPredicate(Pred);
1981 // Strip off any constant offsets so that we can reason about them.
1982 // It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets
1983 // here and compare base addresses like AliasAnalysis does, however there are
1984 // numerous hazards. AliasAnalysis and its utilities rely on special rules
1985 // governing loads and stores which don't apply to icmps. Also, AliasAnalysis
1986 // doesn't need to guarantee pointer inequality when it says NoAlias.
1987 Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
1988 Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
1990 // If LHS and RHS are related via constant offsets to the same base
1991 // value, we can replace it with an icmp which just compares the offsets.
1993 return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset);
1995 // Various optimizations for (in)equality comparisons.
1996 if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE) {
1997 // Different non-empty allocations that exist at the same time have
1998 // different addresses (if the program can tell). Global variables always
1999 // exist, so they always exist during the lifetime of each other and all
2000 // allocas. Two different allocas usually have different addresses...
2002 // However, if there's an @llvm.stackrestore dynamically in between two
2003 // allocas, they may have the same address. It's tempting to reduce the
2004 // scope of the problem by only looking at *static* allocas here. That would
2005 // cover the majority of allocas while significantly reducing the likelihood
2006 // of having an @llvm.stackrestore pop up in the middle. However, it's not
2007 // actually impossible for an @llvm.stackrestore to pop up in the middle of
2008 // an entry block. Also, if we have a block that's not attached to a
2009 // function, we can't tell if it's "static" under the current definition.
2010 // Theoretically, this problem could be fixed by creating a new kind of
2011 // instruction kind specifically for static allocas. Such a new instruction
2012 // could be required to be at the top of the entry block, thus preventing it
2013 // from being subject to a @llvm.stackrestore. Instcombine could even
2014 // convert regular allocas into these special allocas. It'd be nifty.
2015 // However, until then, this problem remains open.
2017 // So, we'll assume that two non-empty allocas have different addresses
2020 // With all that, if the offsets are within the bounds of their allocations
2021 // (and not one-past-the-end! so we can't use inbounds!), and their
2022 // allocations aren't the same, the pointers are not equal.
2024 // Note that it's not necessary to check for LHS being a global variable
2025 // address, due to canonicalization and constant folding.
2026 if (isa<AllocaInst>(LHS) &&
2027 (isa<AllocaInst>(RHS) || isa<GlobalVariable>(RHS))) {
2028 ConstantInt *LHSOffsetCI = dyn_cast<ConstantInt>(LHSOffset);
2029 ConstantInt *RHSOffsetCI = dyn_cast<ConstantInt>(RHSOffset);
2030 uint64_t LHSSize, RHSSize;
2031 if (LHSOffsetCI && RHSOffsetCI &&
2032 getObjectSize(LHS, LHSSize, DL, TLI) &&
2033 getObjectSize(RHS, RHSSize, DL, TLI)) {
2034 const APInt &LHSOffsetValue = LHSOffsetCI->getValue();
2035 const APInt &RHSOffsetValue = RHSOffsetCI->getValue();
2036 if (!LHSOffsetValue.isNegative() &&
2037 !RHSOffsetValue.isNegative() &&
2038 LHSOffsetValue.ult(LHSSize) &&
2039 RHSOffsetValue.ult(RHSSize)) {
2040 return ConstantInt::get(GetCompareTy(LHS),
2041 !CmpInst::isTrueWhenEqual(Pred));
2045 // Repeat the above check but this time without depending on DataLayout
2046 // or being able to compute a precise size.
2047 if (!cast<PointerType>(LHS->getType())->isEmptyTy() &&
2048 !cast<PointerType>(RHS->getType())->isEmptyTy() &&
2049 LHSOffset->isNullValue() &&
2050 RHSOffset->isNullValue())
2051 return ConstantInt::get(GetCompareTy(LHS),
2052 !CmpInst::isTrueWhenEqual(Pred));
2055 // Even if an non-inbounds GEP occurs along the path we can still optimize
2056 // equality comparisons concerning the result. We avoid walking the whole
2057 // chain again by starting where the last calls to
2058 // stripAndComputeConstantOffsets left off and accumulate the offsets.
2059 Constant *LHSNoBound = stripAndComputeConstantOffsets(DL, LHS, true);
2060 Constant *RHSNoBound = stripAndComputeConstantOffsets(DL, RHS, true);
2062 return ConstantExpr::getICmp(Pred,
2063 ConstantExpr::getAdd(LHSOffset, LHSNoBound),
2064 ConstantExpr::getAdd(RHSOffset, RHSNoBound));
2066 // If one side of the equality comparison must come from a noalias call
2067 // (meaning a system memory allocation function), and the other side must
2068 // come from a pointer that cannot overlap with dynamically-allocated
2069 // memory within the lifetime of the current function (allocas, byval
2070 // arguments, globals), then determine the comparison result here.
2071 SmallVector<Value *, 8> LHSUObjs, RHSUObjs;
2072 GetUnderlyingObjects(LHS, LHSUObjs, DL);
2073 GetUnderlyingObjects(RHS, RHSUObjs, DL);
2075 // Is the set of underlying objects all noalias calls?
2076 auto IsNAC = [](SmallVectorImpl<Value *> &Objects) {
2077 return std::all_of(Objects.begin(), Objects.end(),
2078 [](Value *V){ return isNoAliasCall(V); });
2081 // Is the set of underlying objects all things which must be disjoint from
2082 // noalias calls. For allocas, we consider only static ones (dynamic
2083 // allocas might be transformed into calls to malloc not simultaneously
2084 // live with the compared-to allocation). For globals, we exclude symbols
2085 // that might be resolve lazily to symbols in another dynamically-loaded
2086 // library (and, thus, could be malloc'ed by the implementation).
2087 auto IsAllocDisjoint = [](SmallVectorImpl<Value *> &Objects) {
2088 return std::all_of(Objects.begin(), Objects.end(),
2090 if (const AllocaInst *AI = dyn_cast<AllocaInst>(V))
2091 return AI->getParent() && AI->getParent()->getParent() &&
2092 AI->isStaticAlloca();
2093 if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
2094 return (GV->hasLocalLinkage() ||
2095 GV->hasHiddenVisibility() ||
2096 GV->hasProtectedVisibility() ||
2097 GV->hasUnnamedAddr()) &&
2098 !GV->isThreadLocal();
2099 if (const Argument *A = dyn_cast<Argument>(V))
2100 return A->hasByValAttr();
2105 if ((IsNAC(LHSUObjs) && IsAllocDisjoint(RHSUObjs)) ||
2106 (IsNAC(RHSUObjs) && IsAllocDisjoint(LHSUObjs)))
2107 return ConstantInt::get(GetCompareTy(LHS),
2108 !CmpInst::isTrueWhenEqual(Pred));
2115 /// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
2116 /// fold the result. If not, this returns null.
2117 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2118 const Query &Q, unsigned MaxRecurse) {
2119 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
2120 assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
2122 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
2123 if (Constant *CRHS = dyn_cast<Constant>(RHS))
2124 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
2126 // If we have a constant, make sure it is on the RHS.
2127 std::swap(LHS, RHS);
2128 Pred = CmpInst::getSwappedPredicate(Pred);
2131 Type *ITy = GetCompareTy(LHS); // The return type.
2132 Type *OpTy = LHS->getType(); // The operand type.
2134 // icmp X, X -> true/false
2135 // X icmp undef -> true/false. For example, icmp ugt %X, undef -> false
2136 // because X could be 0.
2137 if (LHS == RHS || isa<UndefValue>(RHS))
2138 return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
2140 // Special case logic when the operands have i1 type.
2141 if (OpTy->getScalarType()->isIntegerTy(1)) {
2144 case ICmpInst::ICMP_EQ:
2146 if (match(RHS, m_One()))
2149 case ICmpInst::ICMP_NE:
2151 if (match(RHS, m_Zero()))
2154 case ICmpInst::ICMP_UGT:
2156 if (match(RHS, m_Zero()))
2159 case ICmpInst::ICMP_UGE:
2161 if (match(RHS, m_One()))
2164 case ICmpInst::ICMP_SLT:
2166 if (match(RHS, m_Zero()))
2169 case ICmpInst::ICMP_SLE:
2171 if (match(RHS, m_One()))
2177 // If we are comparing with zero then try hard since this is a common case.
2178 if (match(RHS, m_Zero())) {
2179 bool LHSKnownNonNegative, LHSKnownNegative;
2181 default: llvm_unreachable("Unknown ICmp predicate!");
2182 case ICmpInst::ICMP_ULT:
2183 return getFalse(ITy);
2184 case ICmpInst::ICMP_UGE:
2185 return getTrue(ITy);
2186 case ICmpInst::ICMP_EQ:
2187 case ICmpInst::ICMP_ULE:
2188 if (isKnownNonZero(LHS, Q.DL, 0, Q.AT, Q.CxtI, Q.DT))
2189 return getFalse(ITy);
2191 case ICmpInst::ICMP_NE:
2192 case ICmpInst::ICMP_UGT:
2193 if (isKnownNonZero(LHS, Q.DL, 0, Q.AT, Q.CxtI, Q.DT))
2194 return getTrue(ITy);
2196 case ICmpInst::ICMP_SLT:
2197 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL,
2198 0, Q.AT, Q.CxtI, Q.DT);
2199 if (LHSKnownNegative)
2200 return getTrue(ITy);
2201 if (LHSKnownNonNegative)
2202 return getFalse(ITy);
2204 case ICmpInst::ICMP_SLE:
2205 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL,
2206 0, Q.AT, Q.CxtI, Q.DT);
2207 if (LHSKnownNegative)
2208 return getTrue(ITy);
2209 if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.DL,
2210 0, Q.AT, Q.CxtI, Q.DT))
2211 return getFalse(ITy);
2213 case ICmpInst::ICMP_SGE:
2214 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL,
2215 0, Q.AT, Q.CxtI, Q.DT);
2216 if (LHSKnownNegative)
2217 return getFalse(ITy);
2218 if (LHSKnownNonNegative)
2219 return getTrue(ITy);
2221 case ICmpInst::ICMP_SGT:
2222 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.DL,
2223 0, Q.AT, Q.CxtI, Q.DT);
2224 if (LHSKnownNegative)
2225 return getFalse(ITy);
2226 if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.DL,
2227 0, Q.AT, Q.CxtI, Q.DT))
2228 return getTrue(ITy);
2233 // See if we are doing a comparison with a constant integer.
2234 if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2235 // Rule out tautological comparisons (eg., ult 0 or uge 0).
2236 ConstantRange RHS_CR = ICmpInst::makeConstantRange(Pred, CI->getValue());
2237 if (RHS_CR.isEmptySet())
2238 return ConstantInt::getFalse(CI->getContext());
2239 if (RHS_CR.isFullSet())
2240 return ConstantInt::getTrue(CI->getContext());
2242 // Many binary operators with constant RHS have easy to compute constant
2243 // range. Use them to check whether the comparison is a tautology.
2244 unsigned Width = CI->getBitWidth();
2245 APInt Lower = APInt(Width, 0);
2246 APInt Upper = APInt(Width, 0);
2248 if (match(LHS, m_URem(m_Value(), m_ConstantInt(CI2)))) {
2249 // 'urem x, CI2' produces [0, CI2).
2250 Upper = CI2->getValue();
2251 } else if (match(LHS, m_SRem(m_Value(), m_ConstantInt(CI2)))) {
2252 // 'srem x, CI2' produces (-|CI2|, |CI2|).
2253 Upper = CI2->getValue().abs();
2254 Lower = (-Upper) + 1;
2255 } else if (match(LHS, m_UDiv(m_ConstantInt(CI2), m_Value()))) {
2256 // 'udiv CI2, x' produces [0, CI2].
2257 Upper = CI2->getValue() + 1;
2258 } else if (match(LHS, m_UDiv(m_Value(), m_ConstantInt(CI2)))) {
2259 // 'udiv x, CI2' produces [0, UINT_MAX / CI2].
2260 APInt NegOne = APInt::getAllOnesValue(Width);
2262 Upper = NegOne.udiv(CI2->getValue()) + 1;
2263 } else if (match(LHS, m_SDiv(m_ConstantInt(CI2), m_Value()))) {
2264 if (CI2->isMinSignedValue()) {
2265 // 'sdiv INT_MIN, x' produces [INT_MIN, INT_MIN / -2].
2266 Lower = CI2->getValue();
2267 Upper = Lower.lshr(1) + 1;
2269 // 'sdiv CI2, x' produces [-|CI2|, |CI2|].
2270 Upper = CI2->getValue().abs() + 1;
2271 Lower = (-Upper) + 1;
2273 } else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) {
2274 APInt IntMin = APInt::getSignedMinValue(Width);
2275 APInt IntMax = APInt::getSignedMaxValue(Width);
2276 APInt Val = CI2->getValue();
2277 if (Val.isAllOnesValue()) {
2278 // 'sdiv x, -1' produces [INT_MIN + 1, INT_MAX]
2279 // where CI2 != -1 and CI2 != 0 and CI2 != 1
2282 } else if (Val.countLeadingZeros() < Width - 1) {
2283 // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2]
2284 // where CI2 != -1 and CI2 != 0 and CI2 != 1
2285 Lower = IntMin.sdiv(Val);
2286 Upper = IntMax.sdiv(Val);
2287 if (Lower.sgt(Upper))
2288 std::swap(Lower, Upper);
2290 assert(Upper != Lower && "Upper part of range has wrapped!");
2292 } else if (match(LHS, m_NUWShl(m_ConstantInt(CI2), m_Value()))) {
2293 // 'shl nuw CI2, x' produces [CI2, CI2 << CLZ(CI2)]
2294 Lower = CI2->getValue();
2295 Upper = Lower.shl(Lower.countLeadingZeros()) + 1;
2296 } else if (match(LHS, m_NSWShl(m_ConstantInt(CI2), m_Value()))) {
2297 if (CI2->isNegative()) {
2298 // 'shl nsw CI2, x' produces [CI2 << CLO(CI2)-1, CI2]
2299 unsigned ShiftAmount = CI2->getValue().countLeadingOnes() - 1;
2300 Lower = CI2->getValue().shl(ShiftAmount);
2301 Upper = CI2->getValue() + 1;
2303 // 'shl nsw CI2, x' produces [CI2, CI2 << CLZ(CI2)-1]
2304 unsigned ShiftAmount = CI2->getValue().countLeadingZeros() - 1;
2305 Lower = CI2->getValue();
2306 Upper = CI2->getValue().shl(ShiftAmount) + 1;
2308 } else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) {
2309 // 'lshr x, CI2' produces [0, UINT_MAX >> CI2].
2310 APInt NegOne = APInt::getAllOnesValue(Width);
2311 if (CI2->getValue().ult(Width))
2312 Upper = NegOne.lshr(CI2->getValue()) + 1;
2313 } else if (match(LHS, m_LShr(m_ConstantInt(CI2), m_Value()))) {
2314 // 'lshr CI2, x' produces [CI2 >> (Width-1), CI2].
2315 unsigned ShiftAmount = Width - 1;
2316 if (!CI2->isZero() && cast<BinaryOperator>(LHS)->isExact())
2317 ShiftAmount = CI2->getValue().countTrailingZeros();
2318 Lower = CI2->getValue().lshr(ShiftAmount);
2319 Upper = CI2->getValue() + 1;
2320 } else if (match(LHS, m_AShr(m_Value(), m_ConstantInt(CI2)))) {
2321 // 'ashr x, CI2' produces [INT_MIN >> CI2, INT_MAX >> CI2].
2322 APInt IntMin = APInt::getSignedMinValue(Width);
2323 APInt IntMax = APInt::getSignedMaxValue(Width);
2324 if (CI2->getValue().ult(Width)) {
2325 Lower = IntMin.ashr(CI2->getValue());
2326 Upper = IntMax.ashr(CI2->getValue()) + 1;
2328 } else if (match(LHS, m_AShr(m_ConstantInt(CI2), m_Value()))) {
2329 unsigned ShiftAmount = Width - 1;
2330 if (!CI2->isZero() && cast<BinaryOperator>(LHS)->isExact())
2331 ShiftAmount = CI2->getValue().countTrailingZeros();
2332 if (CI2->isNegative()) {
2333 // 'ashr CI2, x' produces [CI2, CI2 >> (Width-1)]
2334 Lower = CI2->getValue();
2335 Upper = CI2->getValue().ashr(ShiftAmount) + 1;
2337 // 'ashr CI2, x' produces [CI2 >> (Width-1), CI2]
2338 Lower = CI2->getValue().ashr(ShiftAmount);
2339 Upper = CI2->getValue() + 1;
2341 } else if (match(LHS, m_Or(m_Value(), m_ConstantInt(CI2)))) {
2342 // 'or x, CI2' produces [CI2, UINT_MAX].
2343 Lower = CI2->getValue();
2344 } else if (match(LHS, m_And(m_Value(), m_ConstantInt(CI2)))) {
2345 // 'and x, CI2' produces [0, CI2].
2346 Upper = CI2->getValue() + 1;
2348 if (Lower != Upper) {
2349 ConstantRange LHS_CR = ConstantRange(Lower, Upper);
2350 if (RHS_CR.contains(LHS_CR))
2351 return ConstantInt::getTrue(RHS->getContext());
2352 if (RHS_CR.inverse().contains(LHS_CR))
2353 return ConstantInt::getFalse(RHS->getContext());
2357 // Compare of cast, for example (zext X) != 0 -> X != 0
2358 if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
2359 Instruction *LI = cast<CastInst>(LHS);
2360 Value *SrcOp = LI->getOperand(0);
2361 Type *SrcTy = SrcOp->getType();
2362 Type *DstTy = LI->getType();
2364 // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
2365 // if the integer type is the same size as the pointer type.
2366 if (MaxRecurse && Q.DL && isa<PtrToIntInst>(LI) &&
2367 Q.DL->getTypeSizeInBits(SrcTy) == DstTy->getPrimitiveSizeInBits()) {
2368 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
2369 // Transfer the cast to the constant.
2370 if (Value *V = SimplifyICmpInst(Pred, SrcOp,
2371 ConstantExpr::getIntToPtr(RHSC, SrcTy),
2374 } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
2375 if (RI->getOperand(0)->getType() == SrcTy)
2376 // Compare without the cast.
2377 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2383 if (isa<ZExtInst>(LHS)) {
2384 // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
2386 if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
2387 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2388 // Compare X and Y. Note that signed predicates become unsigned.
2389 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
2390 SrcOp, RI->getOperand(0), Q,
2394 // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
2395 // too. If not, then try to deduce the result of the comparison.
2396 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2397 // Compute the constant that would happen if we truncated to SrcTy then
2398 // reextended to DstTy.
2399 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2400 Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
2402 // If the re-extended constant didn't change then this is effectively
2403 // also a case of comparing two zero-extended values.
2404 if (RExt == CI && MaxRecurse)
2405 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
2406 SrcOp, Trunc, Q, MaxRecurse-1))
2409 // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
2410 // there. Use this to work out the result of the comparison.
2413 default: llvm_unreachable("Unknown ICmp predicate!");
2415 case ICmpInst::ICMP_EQ:
2416 case ICmpInst::ICMP_UGT:
2417 case ICmpInst::ICMP_UGE:
2418 return ConstantInt::getFalse(CI->getContext());
2420 case ICmpInst::ICMP_NE:
2421 case ICmpInst::ICMP_ULT:
2422 case ICmpInst::ICMP_ULE:
2423 return ConstantInt::getTrue(CI->getContext());
2425 // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
2426 // is non-negative then LHS <s RHS.
2427 case ICmpInst::ICMP_SGT:
2428 case ICmpInst::ICMP_SGE:
2429 return CI->getValue().isNegative() ?
2430 ConstantInt::getTrue(CI->getContext()) :
2431 ConstantInt::getFalse(CI->getContext());
2433 case ICmpInst::ICMP_SLT:
2434 case ICmpInst::ICMP_SLE:
2435 return CI->getValue().isNegative() ?
2436 ConstantInt::getFalse(CI->getContext()) :
2437 ConstantInt::getTrue(CI->getContext());
2443 if (isa<SExtInst>(LHS)) {
2444 // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
2446 if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
2447 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2448 // Compare X and Y. Note that the predicate does not change.
2449 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2453 // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
2454 // too. If not, then try to deduce the result of the comparison.
2455 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2456 // Compute the constant that would happen if we truncated to SrcTy then
2457 // reextended to DstTy.
2458 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2459 Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
2461 // If the re-extended constant didn't change then this is effectively
2462 // also a case of comparing two sign-extended values.
2463 if (RExt == CI && MaxRecurse)
2464 if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
2467 // Otherwise the upper bits of LHS are all equal, while RHS has varying
2468 // bits there. Use this to work out the result of the comparison.
2471 default: llvm_unreachable("Unknown ICmp predicate!");
2472 case ICmpInst::ICMP_EQ:
2473 return ConstantInt::getFalse(CI->getContext());
2474 case ICmpInst::ICMP_NE:
2475 return ConstantInt::getTrue(CI->getContext());
2477 // If RHS is non-negative then LHS <s RHS. If RHS is negative then
2479 case ICmpInst::ICMP_SGT:
2480 case ICmpInst::ICMP_SGE:
2481 return CI->getValue().isNegative() ?
2482 ConstantInt::getTrue(CI->getContext()) :
2483 ConstantInt::getFalse(CI->getContext());
2484 case ICmpInst::ICMP_SLT:
2485 case ICmpInst::ICMP_SLE:
2486 return CI->getValue().isNegative() ?
2487 ConstantInt::getFalse(CI->getContext()) :
2488 ConstantInt::getTrue(CI->getContext());
2490 // If LHS is non-negative then LHS <u RHS. If LHS is negative then
2492 case ICmpInst::ICMP_UGT:
2493 case ICmpInst::ICMP_UGE:
2494 // Comparison is true iff the LHS <s 0.
2496 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
2497 Constant::getNullValue(SrcTy),
2501 case ICmpInst::ICMP_ULT:
2502 case ICmpInst::ICMP_ULE:
2503 // Comparison is true iff the LHS >=s 0.
2505 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
2506 Constant::getNullValue(SrcTy),
2516 // Special logic for binary operators.
2517 BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
2518 BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
2519 if (MaxRecurse && (LBO || RBO)) {
2520 // Analyze the case when either LHS or RHS is an add instruction.
2521 Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
2522 // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
2523 bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
2524 if (LBO && LBO->getOpcode() == Instruction::Add) {
2525 A = LBO->getOperand(0); B = LBO->getOperand(1);
2526 NoLHSWrapProblem = ICmpInst::isEquality(Pred) ||
2527 (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
2528 (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
2530 if (RBO && RBO->getOpcode() == Instruction::Add) {
2531 C = RBO->getOperand(0); D = RBO->getOperand(1);
2532 NoRHSWrapProblem = ICmpInst::isEquality(Pred) ||
2533 (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
2534 (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
2537 // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
2538 if ((A == RHS || B == RHS) && NoLHSWrapProblem)
2539 if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
2540 Constant::getNullValue(RHS->getType()),
2544 // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
2545 if ((C == LHS || D == LHS) && NoRHSWrapProblem)
2546 if (Value *V = SimplifyICmpInst(Pred,
2547 Constant::getNullValue(LHS->getType()),
2548 C == LHS ? D : C, Q, MaxRecurse-1))
2551 // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
2552 if (A && C && (A == C || A == D || B == C || B == D) &&
2553 NoLHSWrapProblem && NoRHSWrapProblem) {
2554 // Determine Y and Z in the form icmp (X+Y), (X+Z).
2557 // C + B == C + D -> B == D
2560 } else if (A == D) {
2561 // D + B == C + D -> B == C
2564 } else if (B == C) {
2565 // A + C == C + D -> A == D
2570 // A + D == C + D -> A == C
2574 if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse-1))
2579 // icmp pred (or X, Y), X
2580 if (LBO && match(LBO, m_CombineOr(m_Or(m_Value(), m_Specific(RHS)),
2581 m_Or(m_Specific(RHS), m_Value())))) {
2582 if (Pred == ICmpInst::ICMP_ULT)
2583 return getFalse(ITy);
2584 if (Pred == ICmpInst::ICMP_UGE)
2585 return getTrue(ITy);
2587 // icmp pred X, (or X, Y)
2588 if (RBO && match(RBO, m_CombineOr(m_Or(m_Value(), m_Specific(LHS)),
2589 m_Or(m_Specific(LHS), m_Value())))) {
2590 if (Pred == ICmpInst::ICMP_ULE)
2591 return getTrue(ITy);
2592 if (Pred == ICmpInst::ICMP_UGT)
2593 return getFalse(ITy);
2596 // icmp pred (and X, Y), X
2597 if (LBO && match(LBO, m_CombineOr(m_And(m_Value(), m_Specific(RHS)),
2598 m_And(m_Specific(RHS), m_Value())))) {
2599 if (Pred == ICmpInst::ICMP_UGT)
2600 return getFalse(ITy);
2601 if (Pred == ICmpInst::ICMP_ULE)
2602 return getTrue(ITy);
2604 // icmp pred X, (and X, Y)
2605 if (RBO && match(RBO, m_CombineOr(m_And(m_Value(), m_Specific(LHS)),
2606 m_And(m_Specific(LHS), m_Value())))) {
2607 if (Pred == ICmpInst::ICMP_UGE)
2608 return getTrue(ITy);
2609 if (Pred == ICmpInst::ICMP_ULT)
2610 return getFalse(ITy);
2613 // 0 - (zext X) pred C
2614 if (!CmpInst::isUnsigned(Pred) && match(LHS, m_Neg(m_ZExt(m_Value())))) {
2615 if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS)) {
2616 if (RHSC->getValue().isStrictlyPositive()) {
2617 if (Pred == ICmpInst::ICMP_SLT)
2618 return ConstantInt::getTrue(RHSC->getContext());
2619 if (Pred == ICmpInst::ICMP_SGE)
2620 return ConstantInt::getFalse(RHSC->getContext());
2621 if (Pred == ICmpInst::ICMP_EQ)
2622 return ConstantInt::getFalse(RHSC->getContext());
2623 if (Pred == ICmpInst::ICMP_NE)
2624 return ConstantInt::getTrue(RHSC->getContext());
2626 if (RHSC->getValue().isNonNegative()) {
2627 if (Pred == ICmpInst::ICMP_SLE)
2628 return ConstantInt::getTrue(RHSC->getContext());
2629 if (Pred == ICmpInst::ICMP_SGT)
2630 return ConstantInt::getFalse(RHSC->getContext());
2635 // icmp pred (urem X, Y), Y
2636 if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
2637 bool KnownNonNegative, KnownNegative;
2641 case ICmpInst::ICMP_SGT:
2642 case ICmpInst::ICMP_SGE:
2643 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.DL,
2644 0, Q.AT, Q.CxtI, Q.DT);
2645 if (!KnownNonNegative)
2648 case ICmpInst::ICMP_EQ:
2649 case ICmpInst::ICMP_UGT:
2650 case ICmpInst::ICMP_UGE:
2651 return getFalse(ITy);
2652 case ICmpInst::ICMP_SLT:
2653 case ICmpInst::ICMP_SLE:
2654 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.DL,
2655 0, Q.AT, Q.CxtI, Q.DT);
2656 if (!KnownNonNegative)
2659 case ICmpInst::ICMP_NE:
2660 case ICmpInst::ICMP_ULT:
2661 case ICmpInst::ICMP_ULE:
2662 return getTrue(ITy);
2666 // icmp pred X, (urem Y, X)
2667 if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
2668 bool KnownNonNegative, KnownNegative;
2672 case ICmpInst::ICMP_SGT:
2673 case ICmpInst::ICMP_SGE:
2674 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.DL,
2675 0, Q.AT, Q.CxtI, Q.DT);
2676 if (!KnownNonNegative)
2679 case ICmpInst::ICMP_NE:
2680 case ICmpInst::ICMP_UGT:
2681 case ICmpInst::ICMP_UGE:
2682 return getTrue(ITy);
2683 case ICmpInst::ICMP_SLT:
2684 case ICmpInst::ICMP_SLE:
2685 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.DL,
2686 0, Q.AT, Q.CxtI, Q.DT);
2687 if (!KnownNonNegative)
2690 case ICmpInst::ICMP_EQ:
2691 case ICmpInst::ICMP_ULT:
2692 case ICmpInst::ICMP_ULE:
2693 return getFalse(ITy);
2698 if (LBO && match(LBO, m_UDiv(m_Specific(RHS), m_Value()))) {
2699 // icmp pred (X /u Y), X
2700 if (Pred == ICmpInst::ICMP_UGT)
2701 return getFalse(ITy);
2702 if (Pred == ICmpInst::ICMP_ULE)
2703 return getTrue(ITy);
2710 // where CI2 is a power of 2 and CI isn't
2711 if (auto *CI = dyn_cast<ConstantInt>(RHS)) {
2712 const APInt *CI2Val, *CIVal = &CI->getValue();
2713 if (LBO && match(LBO, m_Shl(m_APInt(CI2Val), m_Value())) &&
2714 CI2Val->isPowerOf2()) {
2715 if (!CIVal->isPowerOf2()) {
2716 // CI2 << X can equal zero in some circumstances,
2717 // this simplification is unsafe if CI is zero.
2719 // We know it is safe if:
2720 // - The shift is nsw, we can't shift out the one bit.
2721 // - The shift is nuw, we can't shift out the one bit.
2724 if (LBO->hasNoSignedWrap() || LBO->hasNoUnsignedWrap() ||
2725 *CI2Val == 1 || !CI->isZero()) {
2726 if (Pred == ICmpInst::ICMP_EQ)
2727 return ConstantInt::getFalse(RHS->getContext());
2728 if (Pred == ICmpInst::ICMP_NE)
2729 return ConstantInt::getTrue(RHS->getContext());
2732 if (CIVal->isSignBit() && *CI2Val == 1) {
2733 if (Pred == ICmpInst::ICMP_UGT)
2734 return ConstantInt::getFalse(RHS->getContext());
2735 if (Pred == ICmpInst::ICMP_ULE)
2736 return ConstantInt::getTrue(RHS->getContext());
2741 if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
2742 LBO->getOperand(1) == RBO->getOperand(1)) {
2743 switch (LBO->getOpcode()) {
2745 case Instruction::UDiv:
2746 case Instruction::LShr:
2747 if (ICmpInst::isSigned(Pred))
2750 case Instruction::SDiv:
2751 case Instruction::AShr:
2752 if (!LBO->isExact() || !RBO->isExact())
2754 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2755 RBO->getOperand(0), Q, MaxRecurse-1))
2758 case Instruction::Shl: {
2759 bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
2760 bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
2763 if (!NSW && ICmpInst::isSigned(Pred))
2765 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2766 RBO->getOperand(0), Q, MaxRecurse-1))
2773 // Simplify comparisons involving max/min.
2775 CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE;
2776 CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
2778 // Signed variants on "max(a,b)>=a -> true".
2779 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2780 if (A != RHS) std::swap(A, B); // smax(A, B) pred A.
2781 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2782 // We analyze this as smax(A, B) pred A.
2784 } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
2785 (A == LHS || B == LHS)) {
2786 if (A != LHS) std::swap(A, B); // A pred smax(A, B).
2787 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2788 // We analyze this as smax(A, B) swapped-pred A.
2789 P = CmpInst::getSwappedPredicate(Pred);
2790 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2791 (A == RHS || B == RHS)) {
2792 if (A != RHS) std::swap(A, B); // smin(A, B) pred A.
2793 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2794 // We analyze this as smax(-A, -B) swapped-pred -A.
2795 // Note that we do not need to actually form -A or -B thanks to EqP.
2796 P = CmpInst::getSwappedPredicate(Pred);
2797 } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
2798 (A == LHS || B == LHS)) {
2799 if (A != LHS) std::swap(A, B); // A pred smin(A, B).
2800 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2801 // We analyze this as smax(-A, -B) pred -A.
2802 // Note that we do not need to actually form -A or -B thanks to EqP.
2805 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2806 // Cases correspond to "max(A, B) p A".
2810 case CmpInst::ICMP_EQ:
2811 case CmpInst::ICMP_SLE:
2812 // Equivalent to "A EqP B". This may be the same as the condition tested
2813 // in the max/min; if so, we can just return that.
2814 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2816 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2818 // Otherwise, see if "A EqP B" simplifies.
2820 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2823 case CmpInst::ICMP_NE:
2824 case CmpInst::ICMP_SGT: {
2825 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2826 // Equivalent to "A InvEqP B". This may be the same as the condition
2827 // tested in the max/min; if so, we can just return that.
2828 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2830 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2832 // Otherwise, see if "A InvEqP B" simplifies.
2834 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2838 case CmpInst::ICMP_SGE:
2840 return getTrue(ITy);
2841 case CmpInst::ICMP_SLT:
2843 return getFalse(ITy);
2847 // Unsigned variants on "max(a,b)>=a -> true".
2848 P = CmpInst::BAD_ICMP_PREDICATE;
2849 if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2850 if (A != RHS) std::swap(A, B); // umax(A, B) pred A.
2851 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2852 // We analyze this as umax(A, B) pred A.
2854 } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
2855 (A == LHS || B == LHS)) {
2856 if (A != LHS) std::swap(A, B); // A pred umax(A, B).
2857 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2858 // We analyze this as umax(A, B) swapped-pred A.
2859 P = CmpInst::getSwappedPredicate(Pred);
2860 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2861 (A == RHS || B == RHS)) {
2862 if (A != RHS) std::swap(A, B); // umin(A, B) pred A.
2863 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2864 // We analyze this as umax(-A, -B) swapped-pred -A.
2865 // Note that we do not need to actually form -A or -B thanks to EqP.
2866 P = CmpInst::getSwappedPredicate(Pred);
2867 } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
2868 (A == LHS || B == LHS)) {
2869 if (A != LHS) std::swap(A, B); // A pred umin(A, B).
2870 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2871 // We analyze this as umax(-A, -B) pred -A.
2872 // Note that we do not need to actually form -A or -B thanks to EqP.
2875 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2876 // Cases correspond to "max(A, B) p A".
2880 case CmpInst::ICMP_EQ:
2881 case CmpInst::ICMP_ULE:
2882 // Equivalent to "A EqP B". This may be the same as the condition tested
2883 // in the max/min; if so, we can just return that.
2884 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2886 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2888 // Otherwise, see if "A EqP B" simplifies.
2890 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2893 case CmpInst::ICMP_NE:
2894 case CmpInst::ICMP_UGT: {
2895 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2896 // Equivalent to "A InvEqP B". This may be the same as the condition
2897 // tested in the max/min; if so, we can just return that.
2898 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2900 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2902 // Otherwise, see if "A InvEqP B" simplifies.
2904 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2908 case CmpInst::ICMP_UGE:
2910 return getTrue(ITy);
2911 case CmpInst::ICMP_ULT:
2913 return getFalse(ITy);
2917 // Variants on "max(x,y) >= min(x,z)".
2919 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
2920 match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
2921 (A == C || A == D || B == C || B == D)) {
2922 // max(x, ?) pred min(x, ?).
2923 if (Pred == CmpInst::ICMP_SGE)
2925 return getTrue(ITy);
2926 if (Pred == CmpInst::ICMP_SLT)
2928 return getFalse(ITy);
2929 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2930 match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
2931 (A == C || A == D || B == C || B == D)) {
2932 // min(x, ?) pred max(x, ?).
2933 if (Pred == CmpInst::ICMP_SLE)
2935 return getTrue(ITy);
2936 if (Pred == CmpInst::ICMP_SGT)
2938 return getFalse(ITy);
2939 } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
2940 match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
2941 (A == C || A == D || B == C || B == D)) {
2942 // max(x, ?) pred min(x, ?).
2943 if (Pred == CmpInst::ICMP_UGE)
2945 return getTrue(ITy);
2946 if (Pred == CmpInst::ICMP_ULT)
2948 return getFalse(ITy);
2949 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2950 match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
2951 (A == C || A == D || B == C || B == D)) {
2952 // min(x, ?) pred max(x, ?).
2953 if (Pred == CmpInst::ICMP_ULE)
2955 return getTrue(ITy);
2956 if (Pred == CmpInst::ICMP_UGT)
2958 return getFalse(ITy);
2961 // Simplify comparisons of related pointers using a powerful, recursive
2962 // GEP-walk when we have target data available..
2963 if (LHS->getType()->isPointerTy())
2964 if (Constant *C = computePointerICmp(Q.DL, Q.TLI, Pred, LHS, RHS))
2967 if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
2968 if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
2969 if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
2970 GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
2971 (ICmpInst::isEquality(Pred) ||
2972 (GLHS->isInBounds() && GRHS->isInBounds() &&
2973 Pred == ICmpInst::getSignedPredicate(Pred)))) {
2974 // The bases are equal and the indices are constant. Build a constant
2975 // expression GEP with the same indices and a null base pointer to see
2976 // what constant folding can make out of it.
2977 Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
2978 SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
2979 Constant *NewLHS = ConstantExpr::getGetElementPtr(Null, IndicesLHS);
2981 SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
2982 Constant *NewRHS = ConstantExpr::getGetElementPtr(Null, IndicesRHS);
2983 return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
2988 // If a bit is known to be zero for A and known to be one for B,
2989 // then A and B cannot be equal.
2990 if (ICmpInst::isEquality(Pred)) {
2991 if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2992 uint32_t BitWidth = CI->getBitWidth();
2993 APInt LHSKnownZero(BitWidth, 0);
2994 APInt LHSKnownOne(BitWidth, 0);
2995 computeKnownBits(LHS, LHSKnownZero, LHSKnownOne, Q.DL, /*Depth=*/0, Q.AT,
2997 const APInt &RHSVal = CI->getValue();
2998 if (((LHSKnownZero & RHSVal) != 0) || ((LHSKnownOne & ~RHSVal) != 0))
2999 return Pred == ICmpInst::ICMP_EQ
3000 ? ConstantInt::getFalse(CI->getContext())
3001 : ConstantInt::getTrue(CI->getContext());
3005 // If the comparison is with the result of a select instruction, check whether
3006 // comparing with either branch of the select always yields the same value.
3007 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3008 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
3011 // If the comparison is with the result of a phi instruction, check whether
3012 // doing the compare with each incoming phi value yields a common result.
3013 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3014 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
3020 Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3021 const DataLayout *DL,
3022 const TargetLibraryInfo *TLI,
3023 const DominatorTree *DT,
3024 AssumptionTracker *AT,
3025 Instruction *CxtI) {
3026 return ::SimplifyICmpInst(Predicate, LHS, RHS, Query (DL, TLI, DT, AT, CxtI),
3030 /// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can
3031 /// fold the result. If not, this returns null.
3032 static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3033 const Query &Q, unsigned MaxRecurse) {
3034 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
3035 assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
3037 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
3038 if (Constant *CRHS = dyn_cast<Constant>(RHS))
3039 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
3041 // If we have a constant, make sure it is on the RHS.
3042 std::swap(LHS, RHS);
3043 Pred = CmpInst::getSwappedPredicate(Pred);
3046 // Fold trivial predicates.
3047 if (Pred == FCmpInst::FCMP_FALSE)
3048 return ConstantInt::get(GetCompareTy(LHS), 0);
3049 if (Pred == FCmpInst::FCMP_TRUE)
3050 return ConstantInt::get(GetCompareTy(LHS), 1);
3052 if (isa<UndefValue>(RHS)) // fcmp pred X, undef -> undef
3053 return UndefValue::get(GetCompareTy(LHS));
3055 // fcmp x,x -> true/false. Not all compares are foldable.
3057 if (CmpInst::isTrueWhenEqual(Pred))
3058 return ConstantInt::get(GetCompareTy(LHS), 1);
3059 if (CmpInst::isFalseWhenEqual(Pred))
3060 return ConstantInt::get(GetCompareTy(LHS), 0);
3063 // Handle fcmp with constant RHS
3064 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
3065 // If the constant is a nan, see if we can fold the comparison based on it.
3066 if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHSC)) {
3067 if (CFP->getValueAPF().isNaN()) {
3068 if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo"
3069 return ConstantInt::getFalse(CFP->getContext());
3070 assert(FCmpInst::isUnordered(Pred) &&
3071 "Comparison must be either ordered or unordered!");
3072 // True if unordered.
3073 return ConstantInt::getTrue(CFP->getContext());
3075 // Check whether the constant is an infinity.
3076 if (CFP->getValueAPF().isInfinity()) {
3077 if (CFP->getValueAPF().isNegative()) {
3079 case FCmpInst::FCMP_OLT:
3080 // No value is ordered and less than negative infinity.
3081 return ConstantInt::getFalse(CFP->getContext());
3082 case FCmpInst::FCMP_UGE:
3083 // All values are unordered with or at least negative infinity.
3084 return ConstantInt::getTrue(CFP->getContext());
3090 case FCmpInst::FCMP_OGT:
3091 // No value is ordered and greater than infinity.
3092 return ConstantInt::getFalse(CFP->getContext());
3093 case FCmpInst::FCMP_ULE:
3094 // All values are unordered with and at most infinity.
3095 return ConstantInt::getTrue(CFP->getContext());
3104 // If the comparison is with the result of a select instruction, check whether
3105 // comparing with either branch of the select always yields the same value.
3106 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3107 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
3110 // If the comparison is with the result of a phi instruction, check whether
3111 // doing the compare with each incoming phi value yields a common result.
3112 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3113 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
3119 Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3120 const DataLayout *DL,
3121 const TargetLibraryInfo *TLI,
3122 const DominatorTree *DT,
3123 AssumptionTracker *AT,
3124 const Instruction *CxtI) {
3125 return ::SimplifyFCmpInst(Predicate, LHS, RHS, Query (DL, TLI, DT, AT, CxtI),
3129 /// SimplifySelectInst - Given operands for a SelectInst, see if we can fold
3130 /// the result. If not, this returns null.
3131 static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal,
3132 Value *FalseVal, const Query &Q,
3133 unsigned MaxRecurse) {
3134 // select true, X, Y -> X
3135 // select false, X, Y -> Y
3136 if (Constant *CB = dyn_cast<Constant>(CondVal)) {
3137 if (CB->isAllOnesValue())
3139 if (CB->isNullValue())
3143 // select C, X, X -> X
3144 if (TrueVal == FalseVal)
3147 if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y
3148 if (isa<Constant>(TrueVal))
3152 if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X
3154 if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
3157 if (const auto *ICI = dyn_cast<ICmpInst>(CondVal)) {
3160 if (ICI->isEquality() &&
3161 match(ICI->getOperand(0), m_And(m_Value(X), m_APInt(Y))) &&
3162 match(ICI->getOperand(1), m_Zero())) {
3163 ICmpInst::Predicate Pred = ICI->getPredicate();
3165 // (X & Y) == 0 ? X & ~Y : X --> X
3166 // (X & Y) != 0 ? X & ~Y : X --> X & ~Y
3167 if (FalseVal == X && match(TrueVal, m_And(m_Specific(X), m_APInt(C))) &&
3169 return Pred == ICmpInst::ICMP_EQ ? FalseVal : TrueVal;
3170 // (X & Y) == 0 ? X : X & ~Y --> X & ~Y
3171 // (X & Y) != 0 ? X : X & ~Y --> X
3172 if (TrueVal == X && match(FalseVal, m_And(m_Specific(X), m_APInt(C))) &&
3174 return Pred == ICmpInst::ICMP_EQ ? FalseVal : TrueVal;
3176 if (Y->isPowerOf2()) {
3177 // (X & Y) == 0 ? X | Y : X --> X | Y
3178 // (X & Y) != 0 ? X | Y : X --> X
3179 if (FalseVal == X && match(TrueVal, m_Or(m_Specific(X), m_APInt(C))) &&
3181 return Pred == ICmpInst::ICMP_EQ ? TrueVal : FalseVal;
3182 // (X & Y) == 0 ? X : X | Y --> X
3183 // (X & Y) != 0 ? X : X | Y --> X | Y
3184 if (TrueVal == X && match(FalseVal, m_Or(m_Specific(X), m_APInt(C))) &&
3186 return Pred == ICmpInst::ICMP_EQ ? TrueVal : FalseVal;
3194 Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
3195 const DataLayout *DL,
3196 const TargetLibraryInfo *TLI,
3197 const DominatorTree *DT,
3198 AssumptionTracker *AT,
3199 const Instruction *CxtI) {
3200 return ::SimplifySelectInst(Cond, TrueVal, FalseVal,
3201 Query (DL, TLI, DT, AT, CxtI), RecursionLimit);
3204 /// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
3205 /// fold the result. If not, this returns null.
3206 static Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const Query &Q, unsigned) {
3207 // The type of the GEP pointer operand.
3208 PointerType *PtrTy = cast<PointerType>(Ops[0]->getType()->getScalarType());
3209 unsigned AS = PtrTy->getAddressSpace();
3211 // getelementptr P -> P.
3212 if (Ops.size() == 1)
3215 // Compute the (pointer) type returned by the GEP instruction.
3216 Type *LastType = GetElementPtrInst::getIndexedType(PtrTy, Ops.slice(1));
3217 Type *GEPTy = PointerType::get(LastType, AS);
3218 if (VectorType *VT = dyn_cast<VectorType>(Ops[0]->getType()))
3219 GEPTy = VectorType::get(GEPTy, VT->getNumElements());
3221 if (isa<UndefValue>(Ops[0]))
3222 return UndefValue::get(GEPTy);
3224 if (Ops.size() == 2) {
3225 // getelementptr P, 0 -> P.
3226 if (match(Ops[1], m_Zero()))
3229 Type *Ty = PtrTy->getElementType();
3230 if (Q.DL && Ty->isSized()) {
3233 uint64_t TyAllocSize = Q.DL->getTypeAllocSize(Ty);
3234 // getelementptr P, N -> P if P points to a type of zero size.
3235 if (TyAllocSize == 0)
3238 // The following transforms are only safe if the ptrtoint cast
3239 // doesn't truncate the pointers.
3240 if (Ops[1]->getType()->getScalarSizeInBits() ==
3241 Q.DL->getPointerSizeInBits(AS)) {
3242 auto PtrToIntOrZero = [GEPTy](Value *P) -> Value * {
3243 if (match(P, m_Zero()))
3244 return Constant::getNullValue(GEPTy);
3246 if (match(P, m_PtrToInt(m_Value(Temp))))
3247 if (Temp->getType() == GEPTy)
3252 // getelementptr V, (sub P, V) -> P if P points to a type of size 1.
3253 if (TyAllocSize == 1 &&
3254 match(Ops[1], m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0])))))
3255 if (Value *R = PtrToIntOrZero(P))
3258 // getelementptr V, (ashr (sub P, V), C) -> Q
3259 // if P points to a type of size 1 << C.
3261 m_AShr(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3262 m_ConstantInt(C))) &&
3263 TyAllocSize == 1ULL << C)
3264 if (Value *R = PtrToIntOrZero(P))
3267 // getelementptr V, (sdiv (sub P, V), C) -> Q
3268 // if P points to a type of size C.
3270 m_SDiv(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
3271 m_SpecificInt(TyAllocSize))))
3272 if (Value *R = PtrToIntOrZero(P))
3278 // Check to see if this is constant foldable.
3279 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
3280 if (!isa<Constant>(Ops[i]))
3283 return ConstantExpr::getGetElementPtr(cast<Constant>(Ops[0]), Ops.slice(1));
3286 Value *llvm::SimplifyGEPInst(ArrayRef<Value *> Ops, const DataLayout *DL,
3287 const TargetLibraryInfo *TLI,
3288 const DominatorTree *DT, AssumptionTracker *AT,
3289 const Instruction *CxtI) {
3290 return ::SimplifyGEPInst(Ops, Query (DL, TLI, DT, AT, CxtI), RecursionLimit);
3293 /// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we
3294 /// can fold the result. If not, this returns null.
3295 static Value *SimplifyInsertValueInst(Value *Agg, Value *Val,
3296 ArrayRef<unsigned> Idxs, const Query &Q,
3298 if (Constant *CAgg = dyn_cast<Constant>(Agg))
3299 if (Constant *CVal = dyn_cast<Constant>(Val))
3300 return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
3302 // insertvalue x, undef, n -> x
3303 if (match(Val, m_Undef()))
3306 // insertvalue x, (extractvalue y, n), n
3307 if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
3308 if (EV->getAggregateOperand()->getType() == Agg->getType() &&
3309 EV->getIndices() == Idxs) {
3310 // insertvalue undef, (extractvalue y, n), n -> y
3311 if (match(Agg, m_Undef()))
3312 return EV->getAggregateOperand();
3314 // insertvalue y, (extractvalue y, n), n -> y
3315 if (Agg == EV->getAggregateOperand())
3322 Value *llvm::SimplifyInsertValueInst(Value *Agg, Value *Val,
3323 ArrayRef<unsigned> Idxs,
3324 const DataLayout *DL,
3325 const TargetLibraryInfo *TLI,
3326 const DominatorTree *DT,
3327 AssumptionTracker *AT,
3328 const Instruction *CxtI) {
3329 return ::SimplifyInsertValueInst(Agg, Val, Idxs,
3330 Query (DL, TLI, DT, AT, CxtI),
3334 /// SimplifyPHINode - See if we can fold the given phi. If not, returns null.
3335 static Value *SimplifyPHINode(PHINode *PN, const Query &Q) {
3336 // If all of the PHI's incoming values are the same then replace the PHI node
3337 // with the common value.
3338 Value *CommonValue = nullptr;
3339 bool HasUndefInput = false;
3340 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
3341 Value *Incoming = PN->getIncomingValue(i);
3342 // If the incoming value is the phi node itself, it can safely be skipped.
3343 if (Incoming == PN) continue;
3344 if (isa<UndefValue>(Incoming)) {
3345 // Remember that we saw an undef value, but otherwise ignore them.
3346 HasUndefInput = true;
3349 if (CommonValue && Incoming != CommonValue)
3350 return nullptr; // Not the same, bail out.
3351 CommonValue = Incoming;
3354 // If CommonValue is null then all of the incoming values were either undef or
3355 // equal to the phi node itself.
3357 return UndefValue::get(PN->getType());
3359 // If we have a PHI node like phi(X, undef, X), where X is defined by some
3360 // instruction, we cannot return X as the result of the PHI node unless it
3361 // dominates the PHI block.
3363 return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : nullptr;
3368 static Value *SimplifyTruncInst(Value *Op, Type *Ty, const Query &Q, unsigned) {
3369 if (Constant *C = dyn_cast<Constant>(Op))
3370 return ConstantFoldInstOperands(Instruction::Trunc, Ty, C, Q.DL, Q.TLI);
3375 Value *llvm::SimplifyTruncInst(Value *Op, Type *Ty, const DataLayout *DL,
3376 const TargetLibraryInfo *TLI,
3377 const DominatorTree *DT,
3378 AssumptionTracker *AT,
3379 const Instruction *CxtI) {
3380 return ::SimplifyTruncInst(Op, Ty, Query (DL, TLI, DT, AT, CxtI),
3384 //=== Helper functions for higher up the class hierarchy.
3386 /// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
3387 /// fold the result. If not, this returns null.
3388 static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
3389 const Query &Q, unsigned MaxRecurse) {
3391 case Instruction::Add:
3392 return SimplifyAddInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
3394 case Instruction::FAdd:
3395 return SimplifyFAddInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3397 case Instruction::Sub:
3398 return SimplifySubInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
3400 case Instruction::FSub:
3401 return SimplifyFSubInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3403 case Instruction::Mul: return SimplifyMulInst (LHS, RHS, Q, MaxRecurse);
3404 case Instruction::FMul:
3405 return SimplifyFMulInst (LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3406 case Instruction::SDiv: return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
3407 case Instruction::UDiv: return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
3408 case Instruction::FDiv: return SimplifyFDivInst(LHS, RHS, Q, MaxRecurse);
3409 case Instruction::SRem: return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
3410 case Instruction::URem: return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
3411 case Instruction::FRem: return SimplifyFRemInst(LHS, RHS, Q, MaxRecurse);
3412 case Instruction::Shl:
3413 return SimplifyShlInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
3415 case Instruction::LShr:
3416 return SimplifyLShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
3417 case Instruction::AShr:
3418 return SimplifyAShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
3419 case Instruction::And: return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
3420 case Instruction::Or: return SimplifyOrInst (LHS, RHS, Q, MaxRecurse);
3421 case Instruction::Xor: return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
3423 if (Constant *CLHS = dyn_cast<Constant>(LHS))
3424 if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
3425 Constant *COps[] = {CLHS, CRHS};
3426 return ConstantFoldInstOperands(Opcode, LHS->getType(), COps, Q.DL,
3430 // If the operation is associative, try some generic simplifications.
3431 if (Instruction::isAssociative(Opcode))
3432 if (Value *V = SimplifyAssociativeBinOp(Opcode, LHS, RHS, Q, MaxRecurse))
3435 // If the operation is with the result of a select instruction check whether
3436 // operating on either branch of the select always yields the same value.
3437 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3438 if (Value *V = ThreadBinOpOverSelect(Opcode, LHS, RHS, Q, MaxRecurse))
3441 // If the operation is with the result of a phi instruction, check whether
3442 // operating on all incoming values of the phi always yields the same value.
3443 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3444 if (Value *V = ThreadBinOpOverPHI(Opcode, LHS, RHS, Q, MaxRecurse))
3451 Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
3452 const DataLayout *DL, const TargetLibraryInfo *TLI,
3453 const DominatorTree *DT, AssumptionTracker *AT,
3454 const Instruction *CxtI) {
3455 return ::SimplifyBinOp(Opcode, LHS, RHS, Query (DL, TLI, DT, AT, CxtI),
3459 /// SimplifyCmpInst - Given operands for a CmpInst, see if we can
3460 /// fold the result.
3461 static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3462 const Query &Q, unsigned MaxRecurse) {
3463 if (CmpInst::isIntPredicate((CmpInst::Predicate)Predicate))
3464 return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
3465 return SimplifyFCmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
3468 Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3469 const DataLayout *DL, const TargetLibraryInfo *TLI,
3470 const DominatorTree *DT, AssumptionTracker *AT,
3471 const Instruction *CxtI) {
3472 return ::SimplifyCmpInst(Predicate, LHS, RHS, Query (DL, TLI, DT, AT, CxtI),
3476 static bool IsIdempotent(Intrinsic::ID ID) {
3478 default: return false;
3480 // Unary idempotent: f(f(x)) = f(x)
3481 case Intrinsic::fabs:
3482 case Intrinsic::floor:
3483 case Intrinsic::ceil:
3484 case Intrinsic::trunc:
3485 case Intrinsic::rint:
3486 case Intrinsic::nearbyint:
3487 case Intrinsic::round:
3492 template <typename IterTy>
3493 static Value *SimplifyIntrinsic(Intrinsic::ID IID, IterTy ArgBegin, IterTy ArgEnd,
3494 const Query &Q, unsigned MaxRecurse) {
3495 // Perform idempotent optimizations
3496 if (!IsIdempotent(IID))
3500 if (std::distance(ArgBegin, ArgEnd) == 1)
3501 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(*ArgBegin))
3502 if (II->getIntrinsicID() == IID)
3508 template <typename IterTy>
3509 static Value *SimplifyCall(Value *V, IterTy ArgBegin, IterTy ArgEnd,
3510 const Query &Q, unsigned MaxRecurse) {
3511 Type *Ty = V->getType();
3512 if (PointerType *PTy = dyn_cast<PointerType>(Ty))
3513 Ty = PTy->getElementType();
3514 FunctionType *FTy = cast<FunctionType>(Ty);
3516 // call undef -> undef
3517 if (isa<UndefValue>(V))
3518 return UndefValue::get(FTy->getReturnType());
3520 Function *F = dyn_cast<Function>(V);
3524 if (unsigned IID = F->getIntrinsicID())
3526 SimplifyIntrinsic((Intrinsic::ID) IID, ArgBegin, ArgEnd, Q, MaxRecurse))
3529 if (!canConstantFoldCallTo(F))
3532 SmallVector<Constant *, 4> ConstantArgs;
3533 ConstantArgs.reserve(ArgEnd - ArgBegin);
3534 for (IterTy I = ArgBegin, E = ArgEnd; I != E; ++I) {
3535 Constant *C = dyn_cast<Constant>(*I);
3538 ConstantArgs.push_back(C);
3541 return ConstantFoldCall(F, ConstantArgs, Q.TLI);
3544 Value *llvm::SimplifyCall(Value *V, User::op_iterator ArgBegin,
3545 User::op_iterator ArgEnd, const DataLayout *DL,
3546 const TargetLibraryInfo *TLI,
3547 const DominatorTree *DT, AssumptionTracker *AT,
3548 const Instruction *CxtI) {
3549 return ::SimplifyCall(V, ArgBegin, ArgEnd, Query(DL, TLI, DT, AT, CxtI),
3553 Value *llvm::SimplifyCall(Value *V, ArrayRef<Value *> Args,
3554 const DataLayout *DL, const TargetLibraryInfo *TLI,
3555 const DominatorTree *DT, AssumptionTracker *AT,
3556 const Instruction *CxtI) {
3557 return ::SimplifyCall(V, Args.begin(), Args.end(),
3558 Query(DL, TLI, DT, AT, CxtI), RecursionLimit);
3561 /// SimplifyInstruction - See if we can compute a simplified version of this
3562 /// instruction. If not, this returns null.
3563 Value *llvm::SimplifyInstruction(Instruction *I, const DataLayout *DL,
3564 const TargetLibraryInfo *TLI,
3565 const DominatorTree *DT,
3566 AssumptionTracker *AT) {
3569 switch (I->getOpcode()) {
3571 Result = ConstantFoldInstruction(I, DL, TLI);
3573 case Instruction::FAdd:
3574 Result = SimplifyFAddInst(I->getOperand(0), I->getOperand(1),
3575 I->getFastMathFlags(), DL, TLI, DT, AT, I);
3577 case Instruction::Add:
3578 Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
3579 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3580 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3581 DL, TLI, DT, AT, I);
3583 case Instruction::FSub:
3584 Result = SimplifyFSubInst(I->getOperand(0), I->getOperand(1),
3585 I->getFastMathFlags(), DL, TLI, DT, AT, I);
3587 case Instruction::Sub:
3588 Result = SimplifySubInst(I->getOperand(0), I->getOperand(1),
3589 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3590 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3591 DL, TLI, DT, AT, I);
3593 case Instruction::FMul:
3594 Result = SimplifyFMulInst(I->getOperand(0), I->getOperand(1),
3595 I->getFastMathFlags(), DL, TLI, DT, AT, I);
3597 case Instruction::Mul:
3598 Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1),
3599 DL, TLI, DT, AT, I);
3601 case Instruction::SDiv:
3602 Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1),
3603 DL, TLI, DT, AT, I);
3605 case Instruction::UDiv:
3606 Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1),
3607 DL, TLI, DT, AT, I);
3609 case Instruction::FDiv:
3610 Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1),
3611 DL, TLI, DT, AT, I);
3613 case Instruction::SRem:
3614 Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1),
3615 DL, TLI, DT, AT, I);
3617 case Instruction::URem:
3618 Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1),
3619 DL, TLI, DT, AT, I);
3621 case Instruction::FRem:
3622 Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1),
3623 DL, TLI, DT, AT, I);
3625 case Instruction::Shl:
3626 Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1),
3627 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3628 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3629 DL, TLI, DT, AT, I);
3631 case Instruction::LShr:
3632 Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
3633 cast<BinaryOperator>(I)->isExact(),
3634 DL, TLI, DT, AT, I);
3636 case Instruction::AShr:
3637 Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
3638 cast<BinaryOperator>(I)->isExact(),
3639 DL, TLI, DT, AT, I);
3641 case Instruction::And:
3642 Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1),
3643 DL, TLI, DT, AT, I);
3645 case Instruction::Or:
3646 Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), DL, TLI, DT,
3649 case Instruction::Xor:
3650 Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1),
3651 DL, TLI, DT, AT, I);
3653 case Instruction::ICmp:
3654 Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
3655 I->getOperand(0), I->getOperand(1),
3656 DL, TLI, DT, AT, I);
3658 case Instruction::FCmp:
3659 Result = SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(),
3660 I->getOperand(0), I->getOperand(1),
3661 DL, TLI, DT, AT, I);
3663 case Instruction::Select:
3664 Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
3665 I->getOperand(2), DL, TLI, DT, AT, I);
3667 case Instruction::GetElementPtr: {
3668 SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end());
3669 Result = SimplifyGEPInst(Ops, DL, TLI, DT, AT, I);
3672 case Instruction::InsertValue: {
3673 InsertValueInst *IV = cast<InsertValueInst>(I);
3674 Result = SimplifyInsertValueInst(IV->getAggregateOperand(),
3675 IV->getInsertedValueOperand(),
3676 IV->getIndices(), DL, TLI, DT, AT, I);
3679 case Instruction::PHI:
3680 Result = SimplifyPHINode(cast<PHINode>(I), Query (DL, TLI, DT, AT, I));
3682 case Instruction::Call: {
3683 CallSite CS(cast<CallInst>(I));
3684 Result = SimplifyCall(CS.getCalledValue(), CS.arg_begin(), CS.arg_end(),
3685 DL, TLI, DT, AT, I);
3688 case Instruction::Trunc:
3689 Result = SimplifyTruncInst(I->getOperand(0), I->getType(), DL, TLI, DT,
3694 /// If called on unreachable code, the above logic may report that the
3695 /// instruction simplified to itself. Make life easier for users by
3696 /// detecting that case here, returning a safe value instead.
3697 return Result == I ? UndefValue::get(I->getType()) : Result;
3700 /// \brief Implementation of recursive simplification through an instructions
3703 /// This is the common implementation of the recursive simplification routines.
3704 /// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
3705 /// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
3706 /// instructions to process and attempt to simplify it using
3707 /// InstructionSimplify.
3709 /// This routine returns 'true' only when *it* simplifies something. The passed
3710 /// in simplified value does not count toward this.
3711 static bool replaceAndRecursivelySimplifyImpl(Instruction *I, Value *SimpleV,
3712 const DataLayout *DL,
3713 const TargetLibraryInfo *TLI,
3714 const DominatorTree *DT,
3715 AssumptionTracker *AT) {
3716 bool Simplified = false;
3717 SmallSetVector<Instruction *, 8> Worklist;
3719 // If we have an explicit value to collapse to, do that round of the
3720 // simplification loop by hand initially.
3722 for (User *U : I->users())
3724 Worklist.insert(cast<Instruction>(U));
3726 // Replace the instruction with its simplified value.
3727 I->replaceAllUsesWith(SimpleV);
3729 // Gracefully handle edge cases where the instruction is not wired into any
3732 I->eraseFromParent();
3737 // Note that we must test the size on each iteration, the worklist can grow.
3738 for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
3741 // See if this instruction simplifies.
3742 SimpleV = SimplifyInstruction(I, DL, TLI, DT, AT);
3748 // Stash away all the uses of the old instruction so we can check them for
3749 // recursive simplifications after a RAUW. This is cheaper than checking all
3750 // uses of To on the recursive step in most cases.
3751 for (User *U : I->users())
3752 Worklist.insert(cast<Instruction>(U));
3754 // Replace the instruction with its simplified value.
3755 I->replaceAllUsesWith(SimpleV);
3757 // Gracefully handle edge cases where the instruction is not wired into any
3760 I->eraseFromParent();
3765 bool llvm::recursivelySimplifyInstruction(Instruction *I,
3766 const DataLayout *DL,
3767 const TargetLibraryInfo *TLI,
3768 const DominatorTree *DT,
3769 AssumptionTracker *AT) {
3770 return replaceAndRecursivelySimplifyImpl(I, nullptr, DL, TLI, DT, AT);
3773 bool llvm::replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV,
3774 const DataLayout *DL,
3775 const TargetLibraryInfo *TLI,
3776 const DominatorTree *DT,
3777 AssumptionTracker *AT) {
3778 assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!");
3779 assert(SimpleV && "Must provide a simplified value.");
3780 return replaceAndRecursivelySimplifyImpl(I, SimpleV, DL, TLI, DT, AT);