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 #define DEBUG_TYPE "instsimplify"
21 #include "llvm/Analysis/InstructionSimplify.h"
22 #include "llvm/ADT/SetVector.h"
23 #include "llvm/ADT/Statistic.h"
24 #include "llvm/Analysis/ConstantFolding.h"
25 #include "llvm/Analysis/Dominators.h"
26 #include "llvm/Analysis/ValueTracking.h"
27 #include "llvm/Analysis/MemoryBuiltins.h"
28 #include "llvm/IR/DataLayout.h"
29 #include "llvm/IR/GlobalAlias.h"
30 #include "llvm/IR/Operator.h"
31 #include "llvm/Support/ConstantRange.h"
32 #include "llvm/Support/GetElementPtrTypeIterator.h"
33 #include "llvm/Support/PatternMatch.h"
34 #include "llvm/Support/ValueHandle.h"
36 using namespace llvm::PatternMatch;
38 enum { RecursionLimit = 3 };
40 STATISTIC(NumExpand, "Number of expansions");
41 STATISTIC(NumFactor , "Number of factorizations");
42 STATISTIC(NumReassoc, "Number of reassociations");
46 const TargetLibraryInfo *TLI;
47 const DominatorTree *DT;
49 Query(const DataLayout *td, const TargetLibraryInfo *tli,
50 const DominatorTree *dt) : TD(td), TLI(tli), DT(dt) {}
53 static Value *SimplifyAndInst(Value *, Value *, const Query &, unsigned);
54 static Value *SimplifyBinOp(unsigned, Value *, Value *, const Query &,
56 static Value *SimplifyCmpInst(unsigned, Value *, Value *, const Query &,
58 static Value *SimplifyOrInst(Value *, Value *, const Query &, unsigned);
59 static Value *SimplifyXorInst(Value *, Value *, const Query &, unsigned);
60 static Value *SimplifyTruncInst(Value *, Type *, const Query &, unsigned);
62 /// getFalse - For a boolean type, or a vector of boolean type, return false, or
63 /// a vector with every element false, as appropriate for the type.
64 static Constant *getFalse(Type *Ty) {
65 assert(Ty->getScalarType()->isIntegerTy(1) &&
66 "Expected i1 type or a vector of i1!");
67 return Constant::getNullValue(Ty);
70 /// getTrue - For a boolean type, or a vector of boolean type, return true, or
71 /// a vector with every element true, as appropriate for the type.
72 static Constant *getTrue(Type *Ty) {
73 assert(Ty->getScalarType()->isIntegerTy(1) &&
74 "Expected i1 type or a vector of i1!");
75 return Constant::getAllOnesValue(Ty);
78 /// isSameCompare - Is V equivalent to the comparison "LHS Pred RHS"?
79 static bool isSameCompare(Value *V, CmpInst::Predicate Pred, Value *LHS,
81 CmpInst *Cmp = dyn_cast<CmpInst>(V);
84 CmpInst::Predicate CPred = Cmp->getPredicate();
85 Value *CLHS = Cmp->getOperand(0), *CRHS = Cmp->getOperand(1);
86 if (CPred == Pred && CLHS == LHS && CRHS == RHS)
88 return CPred == CmpInst::getSwappedPredicate(Pred) && CLHS == RHS &&
92 /// ValueDominatesPHI - Does the given value dominate the specified phi node?
93 static bool ValueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
94 Instruction *I = dyn_cast<Instruction>(V);
96 // Arguments and constants dominate all instructions.
99 // If we are processing instructions (and/or basic blocks) that have not been
100 // fully added to a function, the parent nodes may still be null. Simply
101 // return the conservative answer in these cases.
102 if (!I->getParent() || !P->getParent() || !I->getParent()->getParent())
105 // If we have a DominatorTree then do a precise test.
107 if (!DT->isReachableFromEntry(P->getParent()))
109 if (!DT->isReachableFromEntry(I->getParent()))
111 return DT->dominates(I, P);
114 // Otherwise, if the instruction is in the entry block, and is not an invoke,
115 // then it obviously dominates all phi nodes.
116 if (I->getParent() == &I->getParent()->getParent()->getEntryBlock() &&
123 /// ExpandBinOp - Simplify "A op (B op' C)" by distributing op over op', turning
124 /// it into "(A op B) op' (A op C)". Here "op" is given by Opcode and "op'" is
125 /// given by OpcodeToExpand, while "A" corresponds to LHS and "B op' C" to RHS.
126 /// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)".
127 /// Returns the simplified value, or null if no simplification was performed.
128 static Value *ExpandBinOp(unsigned Opcode, Value *LHS, Value *RHS,
129 unsigned OpcToExpand, const Query &Q,
130 unsigned MaxRecurse) {
131 Instruction::BinaryOps OpcodeToExpand = (Instruction::BinaryOps)OpcToExpand;
132 // Recursion is always used, so bail out at once if we already hit the limit.
136 // Check whether the expression has the form "(A op' B) op C".
137 if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS))
138 if (Op0->getOpcode() == OpcodeToExpand) {
139 // It does! Try turning it into "(A op C) op' (B op C)".
140 Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS;
141 // Do "A op C" and "B op C" both simplify?
142 if (Value *L = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse))
143 if (Value *R = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
144 // They do! Return "L op' R" if it simplifies or is already available.
145 // If "L op' R" equals "A op' B" then "L op' R" is just the LHS.
146 if ((L == A && R == B) || (Instruction::isCommutative(OpcodeToExpand)
147 && L == B && R == A)) {
151 // Otherwise return "L op' R" if it simplifies.
152 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
159 // Check whether the expression has the form "A op (B op' C)".
160 if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS))
161 if (Op1->getOpcode() == OpcodeToExpand) {
162 // It does! Try turning it into "(A op B) op' (A op C)".
163 Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1);
164 // Do "A op B" and "A op C" both simplify?
165 if (Value *L = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse))
166 if (Value *R = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse)) {
167 // They do! Return "L op' R" if it simplifies or is already available.
168 // If "L op' R" equals "B op' C" then "L op' R" is just the RHS.
169 if ((L == B && R == C) || (Instruction::isCommutative(OpcodeToExpand)
170 && L == C && R == B)) {
174 // Otherwise return "L op' R" if it simplifies.
175 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
185 /// FactorizeBinOp - Simplify "LHS Opcode RHS" by factorizing out a common term
186 /// using the operation OpCodeToExtract. For example, when Opcode is Add and
187 /// OpCodeToExtract is Mul then this tries to turn "(A*B)+(A*C)" into "A*(B+C)".
188 /// Returns the simplified value, or null if no simplification was performed.
189 static Value *FactorizeBinOp(unsigned Opcode, Value *LHS, Value *RHS,
190 unsigned OpcToExtract, const Query &Q,
191 unsigned MaxRecurse) {
192 Instruction::BinaryOps OpcodeToExtract = (Instruction::BinaryOps)OpcToExtract;
193 // Recursion is always used, so bail out at once if we already hit the limit.
197 BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
198 BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
200 if (!Op0 || Op0->getOpcode() != OpcodeToExtract ||
201 !Op1 || Op1->getOpcode() != OpcodeToExtract)
204 // The expression has the form "(A op' B) op (C op' D)".
205 Value *A = Op0->getOperand(0), *B = Op0->getOperand(1);
206 Value *C = Op1->getOperand(0), *D = Op1->getOperand(1);
208 // Use left distributivity, i.e. "X op' (Y op Z) = (X op' Y) op (X op' Z)".
209 // Does the instruction have the form "(A op' B) op (A op' D)" or, in the
210 // commutative case, "(A op' B) op (C op' A)"?
211 if (A == C || (Instruction::isCommutative(OpcodeToExtract) && A == D)) {
212 Value *DD = A == C ? D : C;
213 // Form "A op' (B op DD)" if it simplifies completely.
214 // Does "B op DD" simplify?
215 if (Value *V = SimplifyBinOp(Opcode, B, DD, Q, MaxRecurse)) {
216 // It does! Return "A op' V" if it simplifies or is already available.
217 // If V equals B then "A op' V" is just the LHS. If V equals DD then
218 // "A op' V" is just the RHS.
219 if (V == B || V == DD) {
221 return V == B ? LHS : RHS;
223 // Otherwise return "A op' V" if it simplifies.
224 if (Value *W = SimplifyBinOp(OpcodeToExtract, A, V, Q, MaxRecurse)) {
231 // Use right distributivity, i.e. "(X op Y) op' Z = (X op' Z) op (Y op' Z)".
232 // Does the instruction have the form "(A op' B) op (C op' B)" or, in the
233 // commutative case, "(A op' B) op (B op' D)"?
234 if (B == D || (Instruction::isCommutative(OpcodeToExtract) && B == C)) {
235 Value *CC = B == D ? C : D;
236 // Form "(A op CC) op' B" if it simplifies completely..
237 // Does "A op CC" simplify?
238 if (Value *V = SimplifyBinOp(Opcode, A, CC, Q, MaxRecurse)) {
239 // It does! Return "V op' B" if it simplifies or is already available.
240 // If V equals A then "V op' B" is just the LHS. If V equals CC then
241 // "V op' B" is just the RHS.
242 if (V == A || V == CC) {
244 return V == A ? LHS : RHS;
246 // Otherwise return "V op' B" if it simplifies.
247 if (Value *W = SimplifyBinOp(OpcodeToExtract, V, B, Q, MaxRecurse)) {
257 /// SimplifyAssociativeBinOp - Generic simplifications for associative binary
258 /// operations. Returns the simpler value, or null if none was found.
259 static Value *SimplifyAssociativeBinOp(unsigned Opc, Value *LHS, Value *RHS,
260 const Query &Q, unsigned MaxRecurse) {
261 Instruction::BinaryOps Opcode = (Instruction::BinaryOps)Opc;
262 assert(Instruction::isAssociative(Opcode) && "Not an associative operation!");
264 // Recursion is always used, so bail out at once if we already hit the limit.
268 BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
269 BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
271 // Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely.
272 if (Op0 && Op0->getOpcode() == Opcode) {
273 Value *A = Op0->getOperand(0);
274 Value *B = Op0->getOperand(1);
277 // Does "B op C" simplify?
278 if (Value *V = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
279 // It does! Return "A op V" if it simplifies or is already available.
280 // If V equals B then "A op V" is just the LHS.
281 if (V == B) return LHS;
282 // Otherwise return "A op V" if it simplifies.
283 if (Value *W = SimplifyBinOp(Opcode, A, V, Q, MaxRecurse)) {
290 // Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely.
291 if (Op1 && Op1->getOpcode() == Opcode) {
293 Value *B = Op1->getOperand(0);
294 Value *C = Op1->getOperand(1);
296 // Does "A op B" simplify?
297 if (Value *V = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse)) {
298 // It does! Return "V op C" if it simplifies or is already available.
299 // If V equals B then "V op C" is just the RHS.
300 if (V == B) return RHS;
301 // Otherwise return "V op C" if it simplifies.
302 if (Value *W = SimplifyBinOp(Opcode, V, C, Q, MaxRecurse)) {
309 // The remaining transforms require commutativity as well as associativity.
310 if (!Instruction::isCommutative(Opcode))
313 // Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely.
314 if (Op0 && Op0->getOpcode() == Opcode) {
315 Value *A = Op0->getOperand(0);
316 Value *B = Op0->getOperand(1);
319 // Does "C op A" simplify?
320 if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
321 // It does! Return "V op B" if it simplifies or is already available.
322 // If V equals A then "V op B" is just the LHS.
323 if (V == A) return LHS;
324 // Otherwise return "V op B" if it simplifies.
325 if (Value *W = SimplifyBinOp(Opcode, V, B, Q, MaxRecurse)) {
332 // Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely.
333 if (Op1 && Op1->getOpcode() == Opcode) {
335 Value *B = Op1->getOperand(0);
336 Value *C = Op1->getOperand(1);
338 // Does "C op A" simplify?
339 if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
340 // It does! Return "B op V" if it simplifies or is already available.
341 // If V equals C then "B op V" is just the RHS.
342 if (V == C) return RHS;
343 // Otherwise return "B op V" if it simplifies.
344 if (Value *W = SimplifyBinOp(Opcode, B, V, Q, MaxRecurse)) {
354 /// ThreadBinOpOverSelect - In the case of a binary operation with a select
355 /// instruction as an operand, try to simplify the binop by seeing whether
356 /// evaluating it on both branches of the select results in the same value.
357 /// Returns the common value if so, otherwise returns null.
358 static Value *ThreadBinOpOverSelect(unsigned Opcode, Value *LHS, Value *RHS,
359 const Query &Q, unsigned MaxRecurse) {
360 // Recursion is always used, so bail out at once if we already hit the limit.
365 if (isa<SelectInst>(LHS)) {
366 SI = cast<SelectInst>(LHS);
368 assert(isa<SelectInst>(RHS) && "No select instruction operand!");
369 SI = cast<SelectInst>(RHS);
372 // Evaluate the BinOp on the true and false branches of the select.
376 TV = SimplifyBinOp(Opcode, SI->getTrueValue(), RHS, Q, MaxRecurse);
377 FV = SimplifyBinOp(Opcode, SI->getFalseValue(), RHS, Q, MaxRecurse);
379 TV = SimplifyBinOp(Opcode, LHS, SI->getTrueValue(), Q, MaxRecurse);
380 FV = SimplifyBinOp(Opcode, LHS, SI->getFalseValue(), Q, MaxRecurse);
383 // If they simplified to the same value, then return the common value.
384 // If they both failed to simplify then return null.
388 // If one branch simplified to undef, return the other one.
389 if (TV && isa<UndefValue>(TV))
391 if (FV && isa<UndefValue>(FV))
394 // If applying the operation did not change the true and false select values,
395 // then the result of the binop is the select itself.
396 if (TV == SI->getTrueValue() && FV == SI->getFalseValue())
399 // If one branch simplified and the other did not, and the simplified
400 // value is equal to the unsimplified one, return the simplified value.
401 // For example, select (cond, X, X & Z) & Z -> X & Z.
402 if ((FV && !TV) || (TV && !FV)) {
403 // Check that the simplified value has the form "X op Y" where "op" is the
404 // same as the original operation.
405 Instruction *Simplified = dyn_cast<Instruction>(FV ? FV : TV);
406 if (Simplified && Simplified->getOpcode() == Opcode) {
407 // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS".
408 // We already know that "op" is the same as for the simplified value. See
409 // if the operands match too. If so, return the simplified value.
410 Value *UnsimplifiedBranch = FV ? SI->getTrueValue() : SI->getFalseValue();
411 Value *UnsimplifiedLHS = SI == LHS ? UnsimplifiedBranch : LHS;
412 Value *UnsimplifiedRHS = SI == LHS ? RHS : UnsimplifiedBranch;
413 if (Simplified->getOperand(0) == UnsimplifiedLHS &&
414 Simplified->getOperand(1) == UnsimplifiedRHS)
416 if (Simplified->isCommutative() &&
417 Simplified->getOperand(1) == UnsimplifiedLHS &&
418 Simplified->getOperand(0) == UnsimplifiedRHS)
426 /// ThreadCmpOverSelect - In the case of a comparison with a select instruction,
427 /// try to simplify the comparison by seeing whether both branches of the select
428 /// result in the same value. Returns the common value if so, otherwise returns
430 static Value *ThreadCmpOverSelect(CmpInst::Predicate Pred, Value *LHS,
431 Value *RHS, const Query &Q,
432 unsigned MaxRecurse) {
433 // Recursion is always used, so bail out at once if we already hit the limit.
437 // Make sure the select is on the LHS.
438 if (!isa<SelectInst>(LHS)) {
440 Pred = CmpInst::getSwappedPredicate(Pred);
442 assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!");
443 SelectInst *SI = cast<SelectInst>(LHS);
444 Value *Cond = SI->getCondition();
445 Value *TV = SI->getTrueValue();
446 Value *FV = SI->getFalseValue();
448 // Now that we have "cmp select(Cond, TV, FV), RHS", analyse it.
449 // Does "cmp TV, RHS" simplify?
450 Value *TCmp = SimplifyCmpInst(Pred, TV, RHS, Q, MaxRecurse);
452 // It not only simplified, it simplified to the select condition. Replace
454 TCmp = getTrue(Cond->getType());
456 // It didn't simplify. However if "cmp TV, RHS" is equal to the select
457 // condition then we can replace it with 'true'. Otherwise give up.
458 if (!isSameCompare(Cond, Pred, TV, RHS))
460 TCmp = getTrue(Cond->getType());
463 // Does "cmp FV, RHS" simplify?
464 Value *FCmp = SimplifyCmpInst(Pred, FV, RHS, Q, MaxRecurse);
466 // It not only simplified, it simplified to the select condition. Replace
468 FCmp = getFalse(Cond->getType());
470 // It didn't simplify. However if "cmp FV, RHS" is equal to the select
471 // condition then we can replace it with 'false'. Otherwise give up.
472 if (!isSameCompare(Cond, Pred, FV, RHS))
474 FCmp = getFalse(Cond->getType());
477 // If both sides simplified to the same value, then use it as the result of
478 // the original comparison.
482 // The remaining cases only make sense if the select condition has the same
483 // type as the result of the comparison, so bail out if this is not so.
484 if (Cond->getType()->isVectorTy() != RHS->getType()->isVectorTy())
486 // If the false value simplified to false, then the result of the compare
487 // is equal to "Cond && TCmp". This also catches the case when the false
488 // value simplified to false and the true value to true, returning "Cond".
489 if (match(FCmp, m_Zero()))
490 if (Value *V = SimplifyAndInst(Cond, TCmp, Q, MaxRecurse))
492 // If the true value simplified to true, then the result of the compare
493 // is equal to "Cond || FCmp".
494 if (match(TCmp, m_One()))
495 if (Value *V = SimplifyOrInst(Cond, FCmp, Q, MaxRecurse))
497 // Finally, if the false value simplified to true and the true value to
498 // false, then the result of the compare is equal to "!Cond".
499 if (match(FCmp, m_One()) && match(TCmp, m_Zero()))
501 SimplifyXorInst(Cond, Constant::getAllOnesValue(Cond->getType()),
508 /// ThreadBinOpOverPHI - In the case of a binary operation with an operand that
509 /// is a PHI instruction, try to simplify the binop by seeing whether evaluating
510 /// it on the incoming phi values yields the same result for every value. If so
511 /// returns the common value, otherwise returns null.
512 static Value *ThreadBinOpOverPHI(unsigned Opcode, Value *LHS, Value *RHS,
513 const Query &Q, unsigned MaxRecurse) {
514 // Recursion is always used, so bail out at once if we already hit the limit.
519 if (isa<PHINode>(LHS)) {
520 PI = cast<PHINode>(LHS);
521 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
522 if (!ValueDominatesPHI(RHS, PI, Q.DT))
525 assert(isa<PHINode>(RHS) && "No PHI instruction operand!");
526 PI = cast<PHINode>(RHS);
527 // Bail out if LHS and the phi may be mutually interdependent due to a loop.
528 if (!ValueDominatesPHI(LHS, PI, Q.DT))
532 // Evaluate the BinOp on the incoming phi values.
533 Value *CommonValue = 0;
534 for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
535 Value *Incoming = PI->getIncomingValue(i);
536 // If the incoming value is the phi node itself, it can safely be skipped.
537 if (Incoming == PI) continue;
538 Value *V = PI == LHS ?
539 SimplifyBinOp(Opcode, Incoming, RHS, Q, MaxRecurse) :
540 SimplifyBinOp(Opcode, LHS, Incoming, Q, MaxRecurse);
541 // If the operation failed to simplify, or simplified to a different value
542 // to previously, then give up.
543 if (!V || (CommonValue && V != CommonValue))
551 /// ThreadCmpOverPHI - In the case of a comparison with a PHI instruction, try
552 /// try to simplify the comparison by seeing whether comparing with all of the
553 /// incoming phi values yields the same result every time. If so returns the
554 /// common result, otherwise returns null.
555 static Value *ThreadCmpOverPHI(CmpInst::Predicate Pred, Value *LHS, Value *RHS,
556 const Query &Q, unsigned MaxRecurse) {
557 // Recursion is always used, so bail out at once if we already hit the limit.
561 // Make sure the phi is on the LHS.
562 if (!isa<PHINode>(LHS)) {
564 Pred = CmpInst::getSwappedPredicate(Pred);
566 assert(isa<PHINode>(LHS) && "Not comparing with a phi instruction!");
567 PHINode *PI = cast<PHINode>(LHS);
569 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
570 if (!ValueDominatesPHI(RHS, PI, Q.DT))
573 // Evaluate the BinOp on the incoming phi values.
574 Value *CommonValue = 0;
575 for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
576 Value *Incoming = PI->getIncomingValue(i);
577 // If the incoming value is the phi node itself, it can safely be skipped.
578 if (Incoming == PI) continue;
579 Value *V = SimplifyCmpInst(Pred, Incoming, RHS, Q, MaxRecurse);
580 // If the operation failed to simplify, or simplified to a different value
581 // to previously, then give up.
582 if (!V || (CommonValue && V != CommonValue))
590 /// SimplifyAddInst - Given operands for an Add, see if we can
591 /// fold the result. If not, this returns null.
592 static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
593 const Query &Q, unsigned MaxRecurse) {
594 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
595 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
596 Constant *Ops[] = { CLHS, CRHS };
597 return ConstantFoldInstOperands(Instruction::Add, CLHS->getType(), Ops,
601 // Canonicalize the constant to the RHS.
605 // X + undef -> undef
606 if (match(Op1, m_Undef()))
610 if (match(Op1, m_Zero()))
617 if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) ||
618 match(Op0, m_Sub(m_Value(Y), m_Specific(Op1))))
621 // X + ~X -> -1 since ~X = -X-1
622 if (match(Op0, m_Not(m_Specific(Op1))) ||
623 match(Op1, m_Not(m_Specific(Op0))))
624 return Constant::getAllOnesValue(Op0->getType());
627 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
628 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
631 // Try some generic simplifications for associative operations.
632 if (Value *V = SimplifyAssociativeBinOp(Instruction::Add, Op0, Op1, Q,
636 // Mul distributes over Add. Try some generic simplifications based on this.
637 if (Value *V = FactorizeBinOp(Instruction::Add, Op0, Op1, Instruction::Mul,
641 // Threading Add over selects and phi nodes is pointless, so don't bother.
642 // Threading over the select in "A + select(cond, B, C)" means evaluating
643 // "A+B" and "A+C" and seeing if they are equal; but they are equal if and
644 // only if B and C are equal. If B and C are equal then (since we assume
645 // that operands have already been simplified) "select(cond, B, C)" should
646 // have been simplified to the common value of B and C already. Analysing
647 // "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly
648 // for threading over phi nodes.
653 Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
654 const DataLayout *TD, const TargetLibraryInfo *TLI,
655 const DominatorTree *DT) {
656 return ::SimplifyAddInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT),
660 /// \brief Compute the base pointer and cumulative constant offsets for V.
662 /// This strips all constant offsets off of V, leaving it the base pointer, and
663 /// accumulates the total constant offset applied in the returned constant. It
664 /// returns 0 if V is not a pointer, and returns the constant '0' if there are
665 /// no constant offsets applied.
667 /// This is very similar to GetPointerBaseWithConstantOffset except it doesn't
668 /// follow non-inbounds geps. This allows it to remain usable for icmp ult/etc.
670 static Constant *stripAndComputeConstantOffsets(const DataLayout *TD,
672 bool AllowNonInbounds = false) {
673 assert(V->getType()->getScalarType()->isPointerTy());
675 // Without DataLayout, just be conservative for now. Theoretically, more could
676 // be done in this case.
678 return ConstantInt::get(IntegerType::get(V->getContext(), 64), 0);
680 Type *IntPtrTy = TD->getIntPtrType(V->getType())->getScalarType();
681 APInt Offset = APInt::getNullValue(IntPtrTy->getIntegerBitWidth());
683 // Even though we don't look through PHI nodes, we could be called on an
684 // instruction in an unreachable block, which may be on a cycle.
685 SmallPtrSet<Value *, 4> Visited;
688 if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
689 if ((!AllowNonInbounds && !GEP->isInBounds()) ||
690 !GEP->accumulateConstantOffset(*TD, Offset))
692 V = GEP->getPointerOperand();
693 } else if (Operator::getOpcode(V) == Instruction::BitCast) {
694 V = cast<Operator>(V)->getOperand(0);
695 } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
696 if (GA->mayBeOverridden())
698 V = GA->getAliasee();
702 assert(V->getType()->getScalarType()->isPointerTy() &&
703 "Unexpected operand type!");
704 } while (Visited.insert(V));
706 Constant *OffsetIntPtr = ConstantInt::get(IntPtrTy, Offset);
707 if (V->getType()->isVectorTy())
708 return ConstantVector::getSplat(V->getType()->getVectorNumElements(),
713 /// \brief Compute the constant difference between two pointer values.
714 /// If the difference is not a constant, returns zero.
715 static Constant *computePointerDifference(const DataLayout *TD,
716 Value *LHS, Value *RHS) {
717 Constant *LHSOffset = stripAndComputeConstantOffsets(TD, LHS);
718 Constant *RHSOffset = stripAndComputeConstantOffsets(TD, RHS);
720 // If LHS and RHS are not related via constant offsets to the same base
721 // value, there is nothing we can do here.
725 // Otherwise, the difference of LHS - RHS can be computed as:
727 // = (LHSOffset + Base) - (RHSOffset + Base)
728 // = LHSOffset - RHSOffset
729 return ConstantExpr::getSub(LHSOffset, RHSOffset);
732 /// SimplifySubInst - Given operands for a Sub, see if we can
733 /// fold the result. If not, this returns null.
734 static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
735 const Query &Q, unsigned MaxRecurse) {
736 if (Constant *CLHS = dyn_cast<Constant>(Op0))
737 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
738 Constant *Ops[] = { CLHS, CRHS };
739 return ConstantFoldInstOperands(Instruction::Sub, CLHS->getType(),
743 // X - undef -> undef
744 // undef - X -> undef
745 if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
746 return UndefValue::get(Op0->getType());
749 if (match(Op1, m_Zero()))
754 return Constant::getNullValue(Op0->getType());
759 if (match(Op0, m_Mul(m_Specific(Op1), m_ConstantInt<2>())) ||
760 match(Op0, m_Shl(m_Specific(Op1), m_One())))
763 // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
764 // For example, (X + Y) - Y -> X; (Y + X) - Y -> X
765 Value *Y = 0, *Z = Op1;
766 if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z
767 // See if "V === Y - Z" simplifies.
768 if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, Q, MaxRecurse-1))
769 // It does! Now see if "X + V" simplifies.
770 if (Value *W = SimplifyBinOp(Instruction::Add, X, V, Q, MaxRecurse-1)) {
771 // It does, we successfully reassociated!
775 // See if "V === X - Z" simplifies.
776 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
777 // It does! Now see if "Y + V" simplifies.
778 if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, Q, MaxRecurse-1)) {
779 // It does, we successfully reassociated!
785 // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
786 // For example, X - (X + 1) -> -1
788 if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z)
789 // See if "V === X - Y" simplifies.
790 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
791 // It does! Now see if "V - Z" simplifies.
792 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, Q, MaxRecurse-1)) {
793 // It does, we successfully reassociated!
797 // See if "V === X - Z" simplifies.
798 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
799 // It does! Now see if "V - Y" simplifies.
800 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, Q, MaxRecurse-1)) {
801 // It does, we successfully reassociated!
807 // Z - (X - Y) -> (Z - X) + Y if everything simplifies.
808 // For example, X - (X - Y) -> Y.
810 if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y)
811 // See if "V === Z - X" simplifies.
812 if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, Q, MaxRecurse-1))
813 // It does! Now see if "V + Y" simplifies.
814 if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, Q, MaxRecurse-1)) {
815 // It does, we successfully reassociated!
820 // trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies.
821 if (MaxRecurse && match(Op0, m_Trunc(m_Value(X))) &&
822 match(Op1, m_Trunc(m_Value(Y))))
823 if (X->getType() == Y->getType())
824 // See if "V === X - Y" simplifies.
825 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
826 // It does! Now see if "trunc V" simplifies.
827 if (Value *W = SimplifyTruncInst(V, Op0->getType(), Q, MaxRecurse-1))
828 // It does, return the simplified "trunc V".
831 // Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...).
832 if (match(Op0, m_PtrToInt(m_Value(X))) &&
833 match(Op1, m_PtrToInt(m_Value(Y))))
834 if (Constant *Result = computePointerDifference(Q.TD, X, Y))
835 return ConstantExpr::getIntegerCast(Result, Op0->getType(), true);
837 // Mul distributes over Sub. Try some generic simplifications based on this.
838 if (Value *V = FactorizeBinOp(Instruction::Sub, Op0, Op1, Instruction::Mul,
843 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
844 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
847 // Threading Sub over selects and phi nodes is pointless, so don't bother.
848 // Threading over the select in "A - select(cond, B, C)" means evaluating
849 // "A-B" and "A-C" and seeing if they are equal; but they are equal if and
850 // only if B and C are equal. If B and C are equal then (since we assume
851 // that operands have already been simplified) "select(cond, B, C)" should
852 // have been simplified to the common value of B and C already. Analysing
853 // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly
854 // for threading over phi nodes.
859 Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
860 const DataLayout *TD, const TargetLibraryInfo *TLI,
861 const DominatorTree *DT) {
862 return ::SimplifySubInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT),
866 /// Given operands for an FAdd, see if we can fold the result. If not, this
868 static Value *SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
869 const Query &Q, unsigned MaxRecurse) {
870 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
871 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
872 Constant *Ops[] = { CLHS, CRHS };
873 return ConstantFoldInstOperands(Instruction::FAdd, CLHS->getType(),
877 // Canonicalize the constant to the RHS.
882 if (match(Op1, m_NegZero()))
885 // fadd X, 0 ==> X, when we know X is not -0
886 if (match(Op1, m_Zero()) &&
887 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
890 // fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
891 // where nnan and ninf have to occur at least once somewhere in this
894 if (match(Op1, m_FSub(m_AnyZero(), m_Specific(Op0))))
896 else if (match(Op0, m_FSub(m_AnyZero(), m_Specific(Op1))))
899 Instruction *FSub = cast<Instruction>(SubOp);
900 if ((FMF.noNaNs() || FSub->hasNoNaNs()) &&
901 (FMF.noInfs() || FSub->hasNoInfs()))
902 return Constant::getNullValue(Op0->getType());
908 /// Given operands for an FSub, see if we can fold the result. If not, this
910 static Value *SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
911 const Query &Q, unsigned MaxRecurse) {
912 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
913 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
914 Constant *Ops[] = { CLHS, CRHS };
915 return ConstantFoldInstOperands(Instruction::FSub, CLHS->getType(),
921 if (match(Op1, m_Zero()))
924 // fsub X, -0 ==> X, when we know X is not -0
925 if (match(Op1, m_NegZero()) &&
926 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
929 // fsub 0, (fsub -0.0, X) ==> X
931 if (match(Op0, m_AnyZero())) {
932 if (match(Op1, m_FSub(m_NegZero(), m_Value(X))))
934 if (FMF.noSignedZeros() && match(Op1, m_FSub(m_AnyZero(), m_Value(X))))
938 // fsub nnan ninf x, x ==> 0.0
939 if (FMF.noNaNs() && FMF.noInfs() && Op0 == Op1)
940 return Constant::getNullValue(Op0->getType());
945 /// Given the operands for an FMul, see if we can fold the result
946 static Value *SimplifyFMulInst(Value *Op0, Value *Op1,
949 unsigned MaxRecurse) {
950 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
951 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
952 Constant *Ops[] = { CLHS, CRHS };
953 return ConstantFoldInstOperands(Instruction::FMul, CLHS->getType(),
957 // Canonicalize the constant to the RHS.
962 if (match(Op1, m_FPOne()))
965 // fmul nnan nsz X, 0 ==> 0
966 if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZero()))
972 /// SimplifyMulInst - Given operands for a Mul, see if we can
973 /// fold the result. If not, this returns null.
974 static Value *SimplifyMulInst(Value *Op0, Value *Op1, const Query &Q,
975 unsigned MaxRecurse) {
976 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
977 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
978 Constant *Ops[] = { CLHS, CRHS };
979 return ConstantFoldInstOperands(Instruction::Mul, CLHS->getType(),
983 // Canonicalize the constant to the RHS.
988 if (match(Op1, m_Undef()))
989 return Constant::getNullValue(Op0->getType());
992 if (match(Op1, m_Zero()))
996 if (match(Op1, m_One()))
999 // (X / Y) * Y -> X if the division is exact.
1001 if (match(Op0, m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y
1002 match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0))))) // Y * (X / Y)
1006 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
1007 if (Value *V = SimplifyAndInst(Op0, Op1, Q, MaxRecurse-1))
1010 // Try some generic simplifications for associative operations.
1011 if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, Q,
1015 // Mul distributes over Add. Try some generic simplifications based on this.
1016 if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add,
1020 // If the operation is with the result of a select instruction, check whether
1021 // operating on either branch of the select always yields the same value.
1022 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1023 if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, Q,
1027 // If the operation is with the result of a phi instruction, check whether
1028 // operating on all incoming values of the phi always yields the same value.
1029 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1030 if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, Q,
1037 Value *llvm::SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
1038 const DataLayout *TD, const TargetLibraryInfo *TLI,
1039 const DominatorTree *DT) {
1040 return ::SimplifyFAddInst(Op0, Op1, FMF, Query (TD, TLI, DT), RecursionLimit);
1043 Value *llvm::SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
1044 const DataLayout *TD, const TargetLibraryInfo *TLI,
1045 const DominatorTree *DT) {
1046 return ::SimplifyFSubInst(Op0, Op1, FMF, Query (TD, TLI, DT), RecursionLimit);
1049 Value *llvm::SimplifyFMulInst(Value *Op0, Value *Op1,
1051 const DataLayout *TD,
1052 const TargetLibraryInfo *TLI,
1053 const DominatorTree *DT) {
1054 return ::SimplifyFMulInst(Op0, Op1, FMF, Query (TD, TLI, DT), RecursionLimit);
1057 Value *llvm::SimplifyMulInst(Value *Op0, Value *Op1, const DataLayout *TD,
1058 const TargetLibraryInfo *TLI,
1059 const DominatorTree *DT) {
1060 return ::SimplifyMulInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1063 /// SimplifyDiv - Given operands for an SDiv or UDiv, see if we can
1064 /// fold the result. If not, this returns null.
1065 static Value *SimplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
1066 const Query &Q, unsigned MaxRecurse) {
1067 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1068 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1069 Constant *Ops[] = { C0, C1 };
1070 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI);
1074 bool isSigned = Opcode == Instruction::SDiv;
1076 // X / undef -> undef
1077 if (match(Op1, m_Undef()))
1081 if (match(Op0, m_Undef()))
1082 return Constant::getNullValue(Op0->getType());
1084 // 0 / X -> 0, we don't need to preserve faults!
1085 if (match(Op0, m_Zero()))
1089 if (match(Op1, m_One()))
1092 if (Op0->getType()->isIntegerTy(1))
1093 // It can't be division by zero, hence it must be division by one.
1098 return ConstantInt::get(Op0->getType(), 1);
1100 // (X * Y) / Y -> X if the multiplication does not overflow.
1101 Value *X = 0, *Y = 0;
1102 if (match(Op0, m_Mul(m_Value(X), m_Value(Y))) && (X == Op1 || Y == Op1)) {
1103 if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1
1104 OverflowingBinaryOperator *Mul = cast<OverflowingBinaryOperator>(Op0);
1105 // If the Mul knows it does not overflow, then we are good to go.
1106 if ((isSigned && Mul->hasNoSignedWrap()) ||
1107 (!isSigned && Mul->hasNoUnsignedWrap()))
1109 // If X has the form X = A / Y then X * Y cannot overflow.
1110 if (BinaryOperator *Div = dyn_cast<BinaryOperator>(X))
1111 if (Div->getOpcode() == Opcode && Div->getOperand(1) == Y)
1115 // (X rem Y) / Y -> 0
1116 if ((isSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1117 (!isSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1118 return Constant::getNullValue(Op0->getType());
1120 // If the operation is with the result of a select instruction, check whether
1121 // operating on either branch of the select always yields the same value.
1122 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1123 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1126 // If the operation is with the result of a phi instruction, check whether
1127 // operating on all incoming values of the phi always yields the same value.
1128 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1129 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1135 /// SimplifySDivInst - Given operands for an SDiv, see if we can
1136 /// fold the result. If not, this returns null.
1137 static Value *SimplifySDivInst(Value *Op0, Value *Op1, const Query &Q,
1138 unsigned MaxRecurse) {
1139 if (Value *V = SimplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse))
1145 Value *llvm::SimplifySDivInst(Value *Op0, Value *Op1, const DataLayout *TD,
1146 const TargetLibraryInfo *TLI,
1147 const DominatorTree *DT) {
1148 return ::SimplifySDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1151 /// SimplifyUDivInst - Given operands for a UDiv, see if we can
1152 /// fold the result. If not, this returns null.
1153 static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const Query &Q,
1154 unsigned MaxRecurse) {
1155 if (Value *V = SimplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse))
1161 Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const DataLayout *TD,
1162 const TargetLibraryInfo *TLI,
1163 const DominatorTree *DT) {
1164 return ::SimplifyUDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1167 static Value *SimplifyFDivInst(Value *Op0, Value *Op1, const Query &Q,
1169 // undef / X -> undef (the undef could be a snan).
1170 if (match(Op0, m_Undef()))
1173 // X / undef -> undef
1174 if (match(Op1, m_Undef()))
1180 Value *llvm::SimplifyFDivInst(Value *Op0, Value *Op1, const DataLayout *TD,
1181 const TargetLibraryInfo *TLI,
1182 const DominatorTree *DT) {
1183 return ::SimplifyFDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1186 /// SimplifyRem - Given operands for an SRem or URem, see if we can
1187 /// fold the result. If not, this returns null.
1188 static Value *SimplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
1189 const Query &Q, unsigned MaxRecurse) {
1190 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1191 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1192 Constant *Ops[] = { C0, C1 };
1193 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI);
1197 // X % undef -> undef
1198 if (match(Op1, m_Undef()))
1202 if (match(Op0, m_Undef()))
1203 return Constant::getNullValue(Op0->getType());
1205 // 0 % X -> 0, we don't need to preserve faults!
1206 if (match(Op0, m_Zero()))
1209 // X % 0 -> undef, we don't need to preserve faults!
1210 if (match(Op1, m_Zero()))
1211 return UndefValue::get(Op0->getType());
1214 if (match(Op1, m_One()))
1215 return Constant::getNullValue(Op0->getType());
1217 if (Op0->getType()->isIntegerTy(1))
1218 // It can't be remainder by zero, hence it must be remainder by one.
1219 return Constant::getNullValue(Op0->getType());
1223 return Constant::getNullValue(Op0->getType());
1225 // If the operation is with the result of a select instruction, check whether
1226 // operating on either branch of the select always yields the same value.
1227 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1228 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1231 // If the operation is with the result of a phi instruction, check whether
1232 // operating on all incoming values of the phi always yields the same value.
1233 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1234 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1240 /// SimplifySRemInst - Given operands for an SRem, see if we can
1241 /// fold the result. If not, this returns null.
1242 static Value *SimplifySRemInst(Value *Op0, Value *Op1, const Query &Q,
1243 unsigned MaxRecurse) {
1244 if (Value *V = SimplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse))
1250 Value *llvm::SimplifySRemInst(Value *Op0, Value *Op1, const DataLayout *TD,
1251 const TargetLibraryInfo *TLI,
1252 const DominatorTree *DT) {
1253 return ::SimplifySRemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1256 /// SimplifyURemInst - Given operands for a URem, see if we can
1257 /// fold the result. If not, this returns null.
1258 static Value *SimplifyURemInst(Value *Op0, Value *Op1, const Query &Q,
1259 unsigned MaxRecurse) {
1260 if (Value *V = SimplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse))
1266 Value *llvm::SimplifyURemInst(Value *Op0, Value *Op1, const DataLayout *TD,
1267 const TargetLibraryInfo *TLI,
1268 const DominatorTree *DT) {
1269 return ::SimplifyURemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1272 static Value *SimplifyFRemInst(Value *Op0, Value *Op1, const Query &,
1274 // undef % X -> undef (the undef could be a snan).
1275 if (match(Op0, m_Undef()))
1278 // X % undef -> undef
1279 if (match(Op1, m_Undef()))
1285 Value *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, const DataLayout *TD,
1286 const TargetLibraryInfo *TLI,
1287 const DominatorTree *DT) {
1288 return ::SimplifyFRemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
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.TD, 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 // X shift by undef -> undef because it may shift by the bitwidth.
1311 if (match(Op1, m_Undef()))
1314 // Shifting by the bitwidth or more is undefined.
1315 if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1))
1316 if (CI->getValue().getLimitedValue() >=
1317 Op0->getType()->getScalarSizeInBits())
1318 return UndefValue::get(Op0->getType());
1320 // If the operation is with the result of a select instruction, check whether
1321 // operating on either branch of the select always yields the same value.
1322 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1323 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1326 // If the operation is with the result of a phi instruction, check whether
1327 // operating on all incoming values of the phi always yields the same value.
1328 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1329 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1335 /// SimplifyShlInst - Given operands for an Shl, see if we can
1336 /// fold the result. If not, this returns null.
1337 static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1338 const Query &Q, unsigned MaxRecurse) {
1339 if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse))
1343 if (match(Op0, m_Undef()))
1344 return Constant::getNullValue(Op0->getType());
1346 // (X >> A) << A -> X
1348 if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
1353 Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1354 const DataLayout *TD, const TargetLibraryInfo *TLI,
1355 const DominatorTree *DT) {
1356 return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT),
1360 /// SimplifyLShrInst - Given operands for an LShr, see if we can
1361 /// fold the result. If not, this returns null.
1362 static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1363 const Query &Q, unsigned MaxRecurse) {
1364 if (Value *V = SimplifyShift(Instruction::LShr, Op0, Op1, Q, MaxRecurse))
1369 return Constant::getNullValue(Op0->getType());
1372 if (match(Op0, m_Undef()))
1373 return Constant::getNullValue(Op0->getType());
1375 // (X << A) >> A -> X
1377 if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) &&
1378 cast<OverflowingBinaryOperator>(Op0)->hasNoUnsignedWrap())
1384 Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1385 const DataLayout *TD,
1386 const TargetLibraryInfo *TLI,
1387 const DominatorTree *DT) {
1388 return ::SimplifyLShrInst(Op0, Op1, isExact, Query (TD, TLI, DT),
1392 /// SimplifyAShrInst - Given operands for an AShr, see if we can
1393 /// fold the result. If not, this returns null.
1394 static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1395 const Query &Q, unsigned MaxRecurse) {
1396 if (Value *V = SimplifyShift(Instruction::AShr, Op0, Op1, Q, MaxRecurse))
1401 return Constant::getNullValue(Op0->getType());
1403 // all ones >>a X -> all ones
1404 if (match(Op0, m_AllOnes()))
1407 // undef >>a X -> all ones
1408 if (match(Op0, m_Undef()))
1409 return Constant::getAllOnesValue(Op0->getType());
1411 // (X << A) >> A -> X
1413 if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) &&
1414 cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap())
1420 Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1421 const DataLayout *TD,
1422 const TargetLibraryInfo *TLI,
1423 const DominatorTree *DT) {
1424 return ::SimplifyAShrInst(Op0, Op1, isExact, Query (TD, TLI, DT),
1428 /// SimplifyAndInst - Given operands for an And, see if we can
1429 /// fold the result. If not, this returns null.
1430 static Value *SimplifyAndInst(Value *Op0, Value *Op1, const Query &Q,
1431 unsigned MaxRecurse) {
1432 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1433 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1434 Constant *Ops[] = { CLHS, CRHS };
1435 return ConstantFoldInstOperands(Instruction::And, CLHS->getType(),
1439 // Canonicalize the constant to the RHS.
1440 std::swap(Op0, Op1);
1444 if (match(Op1, m_Undef()))
1445 return Constant::getNullValue(Op0->getType());
1452 if (match(Op1, m_Zero()))
1456 if (match(Op1, m_AllOnes()))
1459 // A & ~A = ~A & A = 0
1460 if (match(Op0, m_Not(m_Specific(Op1))) ||
1461 match(Op1, m_Not(m_Specific(Op0))))
1462 return Constant::getNullValue(Op0->getType());
1465 Value *A = 0, *B = 0;
1466 if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
1467 (A == Op1 || B == Op1))
1471 if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
1472 (A == Op0 || B == Op0))
1475 // A & (-A) = A if A is a power of two or zero.
1476 if (match(Op0, m_Neg(m_Specific(Op1))) ||
1477 match(Op1, m_Neg(m_Specific(Op0)))) {
1478 if (isKnownToBeAPowerOfTwo(Op0, /*OrZero*/true))
1480 if (isKnownToBeAPowerOfTwo(Op1, /*OrZero*/true))
1484 // Try some generic simplifications for associative operations.
1485 if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
1489 // And distributes over Or. Try some generic simplifications based on this.
1490 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1494 // And distributes over Xor. Try some generic simplifications based on this.
1495 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
1499 // Or distributes over And. Try some generic simplifications based on this.
1500 if (Value *V = FactorizeBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1504 // If the operation is with the result of a select instruction, check whether
1505 // operating on either branch of the select always yields the same value.
1506 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1507 if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
1511 // If the operation is with the result of a phi instruction, check whether
1512 // operating on all incoming values of the phi always yields the same value.
1513 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1514 if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
1521 Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const DataLayout *TD,
1522 const TargetLibraryInfo *TLI,
1523 const DominatorTree *DT) {
1524 return ::SimplifyAndInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1527 /// SimplifyOrInst - Given operands for an Or, see if we can
1528 /// fold the result. If not, this returns null.
1529 static Value *SimplifyOrInst(Value *Op0, Value *Op1, const Query &Q,
1530 unsigned MaxRecurse) {
1531 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1532 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1533 Constant *Ops[] = { CLHS, CRHS };
1534 return ConstantFoldInstOperands(Instruction::Or, CLHS->getType(),
1538 // Canonicalize the constant to the RHS.
1539 std::swap(Op0, Op1);
1543 if (match(Op1, m_Undef()))
1544 return Constant::getAllOnesValue(Op0->getType());
1551 if (match(Op1, m_Zero()))
1555 if (match(Op1, m_AllOnes()))
1558 // A | ~A = ~A | A = -1
1559 if (match(Op0, m_Not(m_Specific(Op1))) ||
1560 match(Op1, m_Not(m_Specific(Op0))))
1561 return Constant::getAllOnesValue(Op0->getType());
1564 Value *A = 0, *B = 0;
1565 if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
1566 (A == Op1 || B == Op1))
1570 if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
1571 (A == Op0 || B == Op0))
1574 // ~(A & ?) | A = -1
1575 if (match(Op0, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1576 (A == Op1 || B == Op1))
1577 return Constant::getAllOnesValue(Op1->getType());
1579 // A | ~(A & ?) = -1
1580 if (match(Op1, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1581 (A == Op0 || B == Op0))
1582 return Constant::getAllOnesValue(Op0->getType());
1584 // Try some generic simplifications for associative operations.
1585 if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
1589 // Or distributes over And. Try some generic simplifications based on this.
1590 if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
1594 // And distributes over Or. Try some generic simplifications based on this.
1595 if (Value *V = FactorizeBinOp(Instruction::Or, Op0, Op1, Instruction::And,
1599 // If the operation is with the result of a select instruction, check whether
1600 // operating on either branch of the select always yields the same value.
1601 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1602 if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
1606 // If the operation is with the result of a phi instruction, check whether
1607 // operating on all incoming values of the phi always yields the same value.
1608 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1609 if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
1615 Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const DataLayout *TD,
1616 const TargetLibraryInfo *TLI,
1617 const DominatorTree *DT) {
1618 return ::SimplifyOrInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1621 /// SimplifyXorInst - Given operands for a Xor, see if we can
1622 /// fold the result. If not, this returns null.
1623 static Value *SimplifyXorInst(Value *Op0, Value *Op1, const Query &Q,
1624 unsigned MaxRecurse) {
1625 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1626 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1627 Constant *Ops[] = { CLHS, CRHS };
1628 return ConstantFoldInstOperands(Instruction::Xor, CLHS->getType(),
1632 // Canonicalize the constant to the RHS.
1633 std::swap(Op0, Op1);
1636 // A ^ undef -> undef
1637 if (match(Op1, m_Undef()))
1641 if (match(Op1, m_Zero()))
1646 return Constant::getNullValue(Op0->getType());
1648 // A ^ ~A = ~A ^ A = -1
1649 if (match(Op0, m_Not(m_Specific(Op1))) ||
1650 match(Op1, m_Not(m_Specific(Op0))))
1651 return Constant::getAllOnesValue(Op0->getType());
1653 // Try some generic simplifications for associative operations.
1654 if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
1658 // And distributes over Xor. Try some generic simplifications based on this.
1659 if (Value *V = FactorizeBinOp(Instruction::Xor, Op0, Op1, Instruction::And,
1663 // Threading Xor over selects and phi nodes is pointless, so don't bother.
1664 // Threading over the select in "A ^ select(cond, B, C)" means evaluating
1665 // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
1666 // only if B and C are equal. If B and C are equal then (since we assume
1667 // that operands have already been simplified) "select(cond, B, C)" should
1668 // have been simplified to the common value of B and C already. Analysing
1669 // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
1670 // for threading over phi nodes.
1675 Value *llvm::SimplifyXorInst(Value *Op0, Value *Op1, const DataLayout *TD,
1676 const TargetLibraryInfo *TLI,
1677 const DominatorTree *DT) {
1678 return ::SimplifyXorInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1681 static Type *GetCompareTy(Value *Op) {
1682 return CmpInst::makeCmpResultType(Op->getType());
1685 /// ExtractEquivalentCondition - Rummage around inside V looking for something
1686 /// equivalent to the comparison "LHS Pred RHS". Return such a value if found,
1687 /// otherwise return null. Helper function for analyzing max/min idioms.
1688 static Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred,
1689 Value *LHS, Value *RHS) {
1690 SelectInst *SI = dyn_cast<SelectInst>(V);
1693 CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
1696 Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
1697 if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
1699 if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
1700 LHS == CmpRHS && RHS == CmpLHS)
1705 // A significant optimization not implemented here is assuming that alloca
1706 // addresses are not equal to incoming argument values. They don't *alias*,
1707 // as we say, but that doesn't mean they aren't equal, so we take a
1708 // conservative approach.
1710 // This is inspired in part by C++11 5.10p1:
1711 // "Two pointers of the same type compare equal if and only if they are both
1712 // null, both point to the same function, or both represent the same
1715 // This is pretty permissive.
1717 // It's also partly due to C11 6.5.9p6:
1718 // "Two pointers compare equal if and only if both are null pointers, both are
1719 // pointers to the same object (including a pointer to an object and a
1720 // subobject at its beginning) or function, both are pointers to one past the
1721 // last element of the same array object, or one is a pointer to one past the
1722 // end of one array object and the other is a pointer to the start of a
1723 // different array object that happens to immediately follow the first array
1724 // object in the address space.)
1726 // C11's version is more restrictive, however there's no reason why an argument
1727 // couldn't be a one-past-the-end value for a stack object in the caller and be
1728 // equal to the beginning of a stack object in the callee.
1730 // If the C and C++ standards are ever made sufficiently restrictive in this
1731 // area, it may be possible to update LLVM's semantics accordingly and reinstate
1732 // this optimization.
1733 static Constant *computePointerICmp(const DataLayout *TD,
1734 const TargetLibraryInfo *TLI,
1735 CmpInst::Predicate Pred,
1736 Value *LHS, Value *RHS) {
1737 // First, skip past any trivial no-ops.
1738 LHS = LHS->stripPointerCasts();
1739 RHS = RHS->stripPointerCasts();
1741 // A non-null pointer is not equal to a null pointer.
1742 if (llvm::isKnownNonNull(LHS, TLI) && isa<ConstantPointerNull>(RHS) &&
1743 (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE))
1744 return ConstantInt::get(GetCompareTy(LHS),
1745 !CmpInst::isTrueWhenEqual(Pred));
1747 // We can only fold certain predicates on pointer comparisons.
1752 // Equality comaprisons are easy to fold.
1753 case CmpInst::ICMP_EQ:
1754 case CmpInst::ICMP_NE:
1757 // We can only handle unsigned relational comparisons because 'inbounds' on
1758 // a GEP only protects against unsigned wrapping.
1759 case CmpInst::ICMP_UGT:
1760 case CmpInst::ICMP_UGE:
1761 case CmpInst::ICMP_ULT:
1762 case CmpInst::ICMP_ULE:
1763 // However, we have to switch them to their signed variants to handle
1764 // negative indices from the base pointer.
1765 Pred = ICmpInst::getSignedPredicate(Pred);
1769 // Strip off any constant offsets so that we can reason about them.
1770 // It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets
1771 // here and compare base addresses like AliasAnalysis does, however there are
1772 // numerous hazards. AliasAnalysis and its utilities rely on special rules
1773 // governing loads and stores which don't apply to icmps. Also, AliasAnalysis
1774 // doesn't need to guarantee pointer inequality when it says NoAlias.
1775 Constant *LHSOffset = stripAndComputeConstantOffsets(TD, LHS);
1776 Constant *RHSOffset = stripAndComputeConstantOffsets(TD, RHS);
1778 // If LHS and RHS are related via constant offsets to the same base
1779 // value, we can replace it with an icmp which just compares the offsets.
1781 return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset);
1783 // Various optimizations for (in)equality comparisons.
1784 if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE) {
1785 // Different non-empty allocations that exist at the same time have
1786 // different addresses (if the program can tell). Global variables always
1787 // exist, so they always exist during the lifetime of each other and all
1788 // allocas. Two different allocas usually have different addresses...
1790 // However, if there's an @llvm.stackrestore dynamically in between two
1791 // allocas, they may have the same address. It's tempting to reduce the
1792 // scope of the problem by only looking at *static* allocas here. That would
1793 // cover the majority of allocas while significantly reducing the likelihood
1794 // of having an @llvm.stackrestore pop up in the middle. However, it's not
1795 // actually impossible for an @llvm.stackrestore to pop up in the middle of
1796 // an entry block. Also, if we have a block that's not attached to a
1797 // function, we can't tell if it's "static" under the current definition.
1798 // Theoretically, this problem could be fixed by creating a new kind of
1799 // instruction kind specifically for static allocas. Such a new instruction
1800 // could be required to be at the top of the entry block, thus preventing it
1801 // from being subject to a @llvm.stackrestore. Instcombine could even
1802 // convert regular allocas into these special allocas. It'd be nifty.
1803 // However, until then, this problem remains open.
1805 // So, we'll assume that two non-empty allocas have different addresses
1808 // With all that, if the offsets are within the bounds of their allocations
1809 // (and not one-past-the-end! so we can't use inbounds!), and their
1810 // allocations aren't the same, the pointers are not equal.
1812 // Note that it's not necessary to check for LHS being a global variable
1813 // address, due to canonicalization and constant folding.
1814 if (isa<AllocaInst>(LHS) &&
1815 (isa<AllocaInst>(RHS) || isa<GlobalVariable>(RHS))) {
1816 ConstantInt *LHSOffsetCI = dyn_cast<ConstantInt>(LHSOffset);
1817 ConstantInt *RHSOffsetCI = dyn_cast<ConstantInt>(RHSOffset);
1818 uint64_t LHSSize, RHSSize;
1819 if (LHSOffsetCI && RHSOffsetCI &&
1820 getObjectSize(LHS, LHSSize, TD, TLI) &&
1821 getObjectSize(RHS, RHSSize, TD, TLI)) {
1822 const APInt &LHSOffsetValue = LHSOffsetCI->getValue();
1823 const APInt &RHSOffsetValue = RHSOffsetCI->getValue();
1824 if (!LHSOffsetValue.isNegative() &&
1825 !RHSOffsetValue.isNegative() &&
1826 LHSOffsetValue.ult(LHSSize) &&
1827 RHSOffsetValue.ult(RHSSize)) {
1828 return ConstantInt::get(GetCompareTy(LHS),
1829 !CmpInst::isTrueWhenEqual(Pred));
1833 // Repeat the above check but this time without depending on DataLayout
1834 // or being able to compute a precise size.
1835 if (!cast<PointerType>(LHS->getType())->isEmptyTy() &&
1836 !cast<PointerType>(RHS->getType())->isEmptyTy() &&
1837 LHSOffset->isNullValue() &&
1838 RHSOffset->isNullValue())
1839 return ConstantInt::get(GetCompareTy(LHS),
1840 !CmpInst::isTrueWhenEqual(Pred));
1843 // Even if an non-inbounds GEP occurs along the path we can still optimize
1844 // equality comparisons concerning the result. We avoid walking the whole
1845 // chain again by starting where the last calls to
1846 // stripAndComputeConstantOffsets left off and accumulate the offsets.
1847 Constant *LHSNoBound = stripAndComputeConstantOffsets(TD, LHS, true);
1848 Constant *RHSNoBound = stripAndComputeConstantOffsets(TD, RHS, true);
1850 return ConstantExpr::getICmp(Pred,
1851 ConstantExpr::getAdd(LHSOffset, LHSNoBound),
1852 ConstantExpr::getAdd(RHSOffset, RHSNoBound));
1859 /// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
1860 /// fold the result. If not, this returns null.
1861 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
1862 const Query &Q, unsigned MaxRecurse) {
1863 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
1864 assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
1866 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
1867 if (Constant *CRHS = dyn_cast<Constant>(RHS))
1868 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.TD, Q.TLI);
1870 // If we have a constant, make sure it is on the RHS.
1871 std::swap(LHS, RHS);
1872 Pred = CmpInst::getSwappedPredicate(Pred);
1875 Type *ITy = GetCompareTy(LHS); // The return type.
1876 Type *OpTy = LHS->getType(); // The operand type.
1878 // icmp X, X -> true/false
1879 // X icmp undef -> true/false. For example, icmp ugt %X, undef -> false
1880 // because X could be 0.
1881 if (LHS == RHS || isa<UndefValue>(RHS))
1882 return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
1884 // Special case logic when the operands have i1 type.
1885 if (OpTy->getScalarType()->isIntegerTy(1)) {
1888 case ICmpInst::ICMP_EQ:
1890 if (match(RHS, m_One()))
1893 case ICmpInst::ICMP_NE:
1895 if (match(RHS, m_Zero()))
1898 case ICmpInst::ICMP_UGT:
1900 if (match(RHS, m_Zero()))
1903 case ICmpInst::ICMP_UGE:
1905 if (match(RHS, m_One()))
1908 case ICmpInst::ICMP_SLT:
1910 if (match(RHS, m_Zero()))
1913 case ICmpInst::ICMP_SLE:
1915 if (match(RHS, m_One()))
1921 // If we are comparing with zero then try hard since this is a common case.
1922 if (match(RHS, m_Zero())) {
1923 bool LHSKnownNonNegative, LHSKnownNegative;
1925 default: llvm_unreachable("Unknown ICmp predicate!");
1926 case ICmpInst::ICMP_ULT:
1927 return getFalse(ITy);
1928 case ICmpInst::ICMP_UGE:
1929 return getTrue(ITy);
1930 case ICmpInst::ICMP_EQ:
1931 case ICmpInst::ICMP_ULE:
1932 if (isKnownNonZero(LHS, Q.TD))
1933 return getFalse(ITy);
1935 case ICmpInst::ICMP_NE:
1936 case ICmpInst::ICMP_UGT:
1937 if (isKnownNonZero(LHS, Q.TD))
1938 return getTrue(ITy);
1940 case ICmpInst::ICMP_SLT:
1941 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1942 if (LHSKnownNegative)
1943 return getTrue(ITy);
1944 if (LHSKnownNonNegative)
1945 return getFalse(ITy);
1947 case ICmpInst::ICMP_SLE:
1948 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1949 if (LHSKnownNegative)
1950 return getTrue(ITy);
1951 if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.TD))
1952 return getFalse(ITy);
1954 case ICmpInst::ICMP_SGE:
1955 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1956 if (LHSKnownNegative)
1957 return getFalse(ITy);
1958 if (LHSKnownNonNegative)
1959 return getTrue(ITy);
1961 case ICmpInst::ICMP_SGT:
1962 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1963 if (LHSKnownNegative)
1964 return getFalse(ITy);
1965 if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.TD))
1966 return getTrue(ITy);
1971 // See if we are doing a comparison with a constant integer.
1972 if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
1973 // Rule out tautological comparisons (eg., ult 0 or uge 0).
1974 ConstantRange RHS_CR = ICmpInst::makeConstantRange(Pred, CI->getValue());
1975 if (RHS_CR.isEmptySet())
1976 return ConstantInt::getFalse(CI->getContext());
1977 if (RHS_CR.isFullSet())
1978 return ConstantInt::getTrue(CI->getContext());
1980 // Many binary operators with constant RHS have easy to compute constant
1981 // range. Use them to check whether the comparison is a tautology.
1982 uint32_t Width = CI->getBitWidth();
1983 APInt Lower = APInt(Width, 0);
1984 APInt Upper = APInt(Width, 0);
1986 if (match(LHS, m_URem(m_Value(), m_ConstantInt(CI2)))) {
1987 // 'urem x, CI2' produces [0, CI2).
1988 Upper = CI2->getValue();
1989 } else if (match(LHS, m_SRem(m_Value(), m_ConstantInt(CI2)))) {
1990 // 'srem x, CI2' produces (-|CI2|, |CI2|).
1991 Upper = CI2->getValue().abs();
1992 Lower = (-Upper) + 1;
1993 } else if (match(LHS, m_UDiv(m_ConstantInt(CI2), m_Value()))) {
1994 // 'udiv CI2, x' produces [0, CI2].
1995 Upper = CI2->getValue() + 1;
1996 } else if (match(LHS, m_UDiv(m_Value(), m_ConstantInt(CI2)))) {
1997 // 'udiv x, CI2' produces [0, UINT_MAX / CI2].
1998 APInt NegOne = APInt::getAllOnesValue(Width);
2000 Upper = NegOne.udiv(CI2->getValue()) + 1;
2001 } else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) {
2002 // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2].
2003 APInt IntMin = APInt::getSignedMinValue(Width);
2004 APInt IntMax = APInt::getSignedMaxValue(Width);
2005 APInt Val = CI2->getValue().abs();
2006 if (!Val.isMinValue()) {
2007 Lower = IntMin.sdiv(Val);
2008 Upper = IntMax.sdiv(Val) + 1;
2010 } else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) {
2011 // 'lshr x, CI2' produces [0, UINT_MAX >> CI2].
2012 APInt NegOne = APInt::getAllOnesValue(Width);
2013 if (CI2->getValue().ult(Width))
2014 Upper = NegOne.lshr(CI2->getValue()) + 1;
2015 } else if (match(LHS, m_AShr(m_Value(), m_ConstantInt(CI2)))) {
2016 // 'ashr x, CI2' produces [INT_MIN >> CI2, INT_MAX >> CI2].
2017 APInt IntMin = APInt::getSignedMinValue(Width);
2018 APInt IntMax = APInt::getSignedMaxValue(Width);
2019 if (CI2->getValue().ult(Width)) {
2020 Lower = IntMin.ashr(CI2->getValue());
2021 Upper = IntMax.ashr(CI2->getValue()) + 1;
2023 } else if (match(LHS, m_Or(m_Value(), m_ConstantInt(CI2)))) {
2024 // 'or x, CI2' produces [CI2, UINT_MAX].
2025 Lower = CI2->getValue();
2026 } else if (match(LHS, m_And(m_Value(), m_ConstantInt(CI2)))) {
2027 // 'and x, CI2' produces [0, CI2].
2028 Upper = CI2->getValue() + 1;
2030 if (Lower != Upper) {
2031 ConstantRange LHS_CR = ConstantRange(Lower, Upper);
2032 if (RHS_CR.contains(LHS_CR))
2033 return ConstantInt::getTrue(RHS->getContext());
2034 if (RHS_CR.inverse().contains(LHS_CR))
2035 return ConstantInt::getFalse(RHS->getContext());
2039 // Compare of cast, for example (zext X) != 0 -> X != 0
2040 if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
2041 Instruction *LI = cast<CastInst>(LHS);
2042 Value *SrcOp = LI->getOperand(0);
2043 Type *SrcTy = SrcOp->getType();
2044 Type *DstTy = LI->getType();
2046 // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
2047 // if the integer type is the same size as the pointer type.
2048 if (MaxRecurse && Q.TD && isa<PtrToIntInst>(LI) &&
2049 Q.TD->getTypeSizeInBits(SrcTy) == DstTy->getPrimitiveSizeInBits()) {
2050 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
2051 // Transfer the cast to the constant.
2052 if (Value *V = SimplifyICmpInst(Pred, SrcOp,
2053 ConstantExpr::getIntToPtr(RHSC, SrcTy),
2056 } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
2057 if (RI->getOperand(0)->getType() == SrcTy)
2058 // Compare without the cast.
2059 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2065 if (isa<ZExtInst>(LHS)) {
2066 // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
2068 if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
2069 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2070 // Compare X and Y. Note that signed predicates become unsigned.
2071 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
2072 SrcOp, RI->getOperand(0), Q,
2076 // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
2077 // too. If not, then try to deduce the result of the comparison.
2078 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2079 // Compute the constant that would happen if we truncated to SrcTy then
2080 // reextended to DstTy.
2081 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2082 Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
2084 // If the re-extended constant didn't change then this is effectively
2085 // also a case of comparing two zero-extended values.
2086 if (RExt == CI && MaxRecurse)
2087 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
2088 SrcOp, Trunc, Q, MaxRecurse-1))
2091 // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
2092 // there. Use this to work out the result of the comparison.
2095 default: llvm_unreachable("Unknown ICmp predicate!");
2097 case ICmpInst::ICMP_EQ:
2098 case ICmpInst::ICMP_UGT:
2099 case ICmpInst::ICMP_UGE:
2100 return ConstantInt::getFalse(CI->getContext());
2102 case ICmpInst::ICMP_NE:
2103 case ICmpInst::ICMP_ULT:
2104 case ICmpInst::ICMP_ULE:
2105 return ConstantInt::getTrue(CI->getContext());
2107 // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
2108 // is non-negative then LHS <s RHS.
2109 case ICmpInst::ICMP_SGT:
2110 case ICmpInst::ICMP_SGE:
2111 return CI->getValue().isNegative() ?
2112 ConstantInt::getTrue(CI->getContext()) :
2113 ConstantInt::getFalse(CI->getContext());
2115 case ICmpInst::ICMP_SLT:
2116 case ICmpInst::ICMP_SLE:
2117 return CI->getValue().isNegative() ?
2118 ConstantInt::getFalse(CI->getContext()) :
2119 ConstantInt::getTrue(CI->getContext());
2125 if (isa<SExtInst>(LHS)) {
2126 // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
2128 if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
2129 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2130 // Compare X and Y. Note that the predicate does not change.
2131 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2135 // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
2136 // too. If not, then try to deduce the result of the comparison.
2137 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2138 // Compute the constant that would happen if we truncated to SrcTy then
2139 // reextended to DstTy.
2140 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2141 Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
2143 // If the re-extended constant didn't change then this is effectively
2144 // also a case of comparing two sign-extended values.
2145 if (RExt == CI && MaxRecurse)
2146 if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
2149 // Otherwise the upper bits of LHS are all equal, while RHS has varying
2150 // bits there. Use this to work out the result of the comparison.
2153 default: llvm_unreachable("Unknown ICmp predicate!");
2154 case ICmpInst::ICMP_EQ:
2155 return ConstantInt::getFalse(CI->getContext());
2156 case ICmpInst::ICMP_NE:
2157 return ConstantInt::getTrue(CI->getContext());
2159 // If RHS is non-negative then LHS <s RHS. If RHS is negative then
2161 case ICmpInst::ICMP_SGT:
2162 case ICmpInst::ICMP_SGE:
2163 return CI->getValue().isNegative() ?
2164 ConstantInt::getTrue(CI->getContext()) :
2165 ConstantInt::getFalse(CI->getContext());
2166 case ICmpInst::ICMP_SLT:
2167 case ICmpInst::ICMP_SLE:
2168 return CI->getValue().isNegative() ?
2169 ConstantInt::getFalse(CI->getContext()) :
2170 ConstantInt::getTrue(CI->getContext());
2172 // If LHS is non-negative then LHS <u RHS. If LHS is negative then
2174 case ICmpInst::ICMP_UGT:
2175 case ICmpInst::ICMP_UGE:
2176 // Comparison is true iff the LHS <s 0.
2178 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
2179 Constant::getNullValue(SrcTy),
2183 case ICmpInst::ICMP_ULT:
2184 case ICmpInst::ICMP_ULE:
2185 // Comparison is true iff the LHS >=s 0.
2187 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
2188 Constant::getNullValue(SrcTy),
2198 // Special logic for binary operators.
2199 BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
2200 BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
2201 if (MaxRecurse && (LBO || RBO)) {
2202 // Analyze the case when either LHS or RHS is an add instruction.
2203 Value *A = 0, *B = 0, *C = 0, *D = 0;
2204 // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
2205 bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
2206 if (LBO && LBO->getOpcode() == Instruction::Add) {
2207 A = LBO->getOperand(0); B = LBO->getOperand(1);
2208 NoLHSWrapProblem = ICmpInst::isEquality(Pred) ||
2209 (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
2210 (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
2212 if (RBO && RBO->getOpcode() == Instruction::Add) {
2213 C = RBO->getOperand(0); D = RBO->getOperand(1);
2214 NoRHSWrapProblem = ICmpInst::isEquality(Pred) ||
2215 (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
2216 (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
2219 // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
2220 if ((A == RHS || B == RHS) && NoLHSWrapProblem)
2221 if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
2222 Constant::getNullValue(RHS->getType()),
2226 // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
2227 if ((C == LHS || D == LHS) && NoRHSWrapProblem)
2228 if (Value *V = SimplifyICmpInst(Pred,
2229 Constant::getNullValue(LHS->getType()),
2230 C == LHS ? D : C, Q, MaxRecurse-1))
2233 // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
2234 if (A && C && (A == C || A == D || B == C || B == D) &&
2235 NoLHSWrapProblem && NoRHSWrapProblem) {
2236 // Determine Y and Z in the form icmp (X+Y), (X+Z).
2239 // C + B == C + D -> B == D
2242 } else if (A == D) {
2243 // D + B == C + D -> B == C
2246 } else if (B == C) {
2247 // A + C == C + D -> A == D
2252 // A + D == C + D -> A == C
2256 if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse-1))
2261 // icmp pred (urem X, Y), Y
2262 if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
2263 bool KnownNonNegative, KnownNegative;
2267 case ICmpInst::ICMP_SGT:
2268 case ICmpInst::ICMP_SGE:
2269 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.TD);
2270 if (!KnownNonNegative)
2273 case ICmpInst::ICMP_EQ:
2274 case ICmpInst::ICMP_UGT:
2275 case ICmpInst::ICMP_UGE:
2276 return getFalse(ITy);
2277 case ICmpInst::ICMP_SLT:
2278 case ICmpInst::ICMP_SLE:
2279 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.TD);
2280 if (!KnownNonNegative)
2283 case ICmpInst::ICMP_NE:
2284 case ICmpInst::ICMP_ULT:
2285 case ICmpInst::ICMP_ULE:
2286 return getTrue(ITy);
2290 // icmp pred X, (urem Y, X)
2291 if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
2292 bool KnownNonNegative, KnownNegative;
2296 case ICmpInst::ICMP_SGT:
2297 case ICmpInst::ICMP_SGE:
2298 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.TD);
2299 if (!KnownNonNegative)
2302 case ICmpInst::ICMP_NE:
2303 case ICmpInst::ICMP_UGT:
2304 case ICmpInst::ICMP_UGE:
2305 return getTrue(ITy);
2306 case ICmpInst::ICMP_SLT:
2307 case ICmpInst::ICMP_SLE:
2308 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.TD);
2309 if (!KnownNonNegative)
2312 case ICmpInst::ICMP_EQ:
2313 case ICmpInst::ICMP_ULT:
2314 case ICmpInst::ICMP_ULE:
2315 return getFalse(ITy);
2320 if (LBO && match(LBO, m_UDiv(m_Specific(RHS), m_Value()))) {
2321 // icmp pred (X /u Y), X
2322 if (Pred == ICmpInst::ICMP_UGT)
2323 return getFalse(ITy);
2324 if (Pred == ICmpInst::ICMP_ULE)
2325 return getTrue(ITy);
2328 if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
2329 LBO->getOperand(1) == RBO->getOperand(1)) {
2330 switch (LBO->getOpcode()) {
2332 case Instruction::UDiv:
2333 case Instruction::LShr:
2334 if (ICmpInst::isSigned(Pred))
2337 case Instruction::SDiv:
2338 case Instruction::AShr:
2339 if (!LBO->isExact() || !RBO->isExact())
2341 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2342 RBO->getOperand(0), Q, MaxRecurse-1))
2345 case Instruction::Shl: {
2346 bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
2347 bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
2350 if (!NSW && ICmpInst::isSigned(Pred))
2352 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2353 RBO->getOperand(0), Q, MaxRecurse-1))
2360 // Simplify comparisons involving max/min.
2362 CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE;
2363 CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
2365 // Signed variants on "max(a,b)>=a -> true".
2366 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2367 if (A != RHS) std::swap(A, B); // smax(A, B) pred A.
2368 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2369 // We analyze this as smax(A, B) pred A.
2371 } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
2372 (A == LHS || B == LHS)) {
2373 if (A != LHS) std::swap(A, B); // A pred smax(A, B).
2374 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2375 // We analyze this as smax(A, B) swapped-pred A.
2376 P = CmpInst::getSwappedPredicate(Pred);
2377 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2378 (A == RHS || B == RHS)) {
2379 if (A != RHS) std::swap(A, B); // smin(A, B) pred A.
2380 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2381 // We analyze this as smax(-A, -B) swapped-pred -A.
2382 // Note that we do not need to actually form -A or -B thanks to EqP.
2383 P = CmpInst::getSwappedPredicate(Pred);
2384 } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
2385 (A == LHS || B == LHS)) {
2386 if (A != LHS) std::swap(A, B); // A pred smin(A, B).
2387 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2388 // We analyze this as smax(-A, -B) pred -A.
2389 // Note that we do not need to actually form -A or -B thanks to EqP.
2392 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2393 // Cases correspond to "max(A, B) p A".
2397 case CmpInst::ICMP_EQ:
2398 case CmpInst::ICMP_SLE:
2399 // Equivalent to "A EqP B". This may be the same as the condition tested
2400 // in the max/min; if so, we can just return that.
2401 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2403 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2405 // Otherwise, see if "A EqP B" simplifies.
2407 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2410 case CmpInst::ICMP_NE:
2411 case CmpInst::ICMP_SGT: {
2412 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2413 // Equivalent to "A InvEqP B". This may be the same as the condition
2414 // tested in the max/min; if so, we can just return that.
2415 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2417 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2419 // Otherwise, see if "A InvEqP B" simplifies.
2421 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2425 case CmpInst::ICMP_SGE:
2427 return getTrue(ITy);
2428 case CmpInst::ICMP_SLT:
2430 return getFalse(ITy);
2434 // Unsigned variants on "max(a,b)>=a -> true".
2435 P = CmpInst::BAD_ICMP_PREDICATE;
2436 if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2437 if (A != RHS) std::swap(A, B); // umax(A, B) pred A.
2438 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2439 // We analyze this as umax(A, B) pred A.
2441 } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
2442 (A == LHS || B == LHS)) {
2443 if (A != LHS) std::swap(A, B); // A pred umax(A, B).
2444 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2445 // We analyze this as umax(A, B) swapped-pred A.
2446 P = CmpInst::getSwappedPredicate(Pred);
2447 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2448 (A == RHS || B == RHS)) {
2449 if (A != RHS) std::swap(A, B); // umin(A, B) pred A.
2450 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2451 // We analyze this as umax(-A, -B) swapped-pred -A.
2452 // Note that we do not need to actually form -A or -B thanks to EqP.
2453 P = CmpInst::getSwappedPredicate(Pred);
2454 } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
2455 (A == LHS || B == LHS)) {
2456 if (A != LHS) std::swap(A, B); // A pred umin(A, B).
2457 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2458 // We analyze this as umax(-A, -B) pred -A.
2459 // Note that we do not need to actually form -A or -B thanks to EqP.
2462 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2463 // Cases correspond to "max(A, B) p A".
2467 case CmpInst::ICMP_EQ:
2468 case CmpInst::ICMP_ULE:
2469 // Equivalent to "A EqP B". This may be the same as the condition tested
2470 // in the max/min; if so, we can just return that.
2471 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2473 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2475 // Otherwise, see if "A EqP B" simplifies.
2477 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2480 case CmpInst::ICMP_NE:
2481 case CmpInst::ICMP_UGT: {
2482 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2483 // Equivalent to "A InvEqP B". This may be the same as the condition
2484 // tested in the max/min; if so, we can just return that.
2485 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2487 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2489 // Otherwise, see if "A InvEqP B" simplifies.
2491 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2495 case CmpInst::ICMP_UGE:
2497 return getTrue(ITy);
2498 case CmpInst::ICMP_ULT:
2500 return getFalse(ITy);
2504 // Variants on "max(x,y) >= min(x,z)".
2506 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
2507 match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
2508 (A == C || A == D || B == C || B == D)) {
2509 // max(x, ?) pred min(x, ?).
2510 if (Pred == CmpInst::ICMP_SGE)
2512 return getTrue(ITy);
2513 if (Pred == CmpInst::ICMP_SLT)
2515 return getFalse(ITy);
2516 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2517 match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
2518 (A == C || A == D || B == C || B == D)) {
2519 // min(x, ?) pred max(x, ?).
2520 if (Pred == CmpInst::ICMP_SLE)
2522 return getTrue(ITy);
2523 if (Pred == CmpInst::ICMP_SGT)
2525 return getFalse(ITy);
2526 } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
2527 match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
2528 (A == C || A == D || B == C || B == D)) {
2529 // max(x, ?) pred min(x, ?).
2530 if (Pred == CmpInst::ICMP_UGE)
2532 return getTrue(ITy);
2533 if (Pred == CmpInst::ICMP_ULT)
2535 return getFalse(ITy);
2536 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2537 match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
2538 (A == C || A == D || B == C || B == D)) {
2539 // min(x, ?) pred max(x, ?).
2540 if (Pred == CmpInst::ICMP_ULE)
2542 return getTrue(ITy);
2543 if (Pred == CmpInst::ICMP_UGT)
2545 return getFalse(ITy);
2548 // Simplify comparisons of related pointers using a powerful, recursive
2549 // GEP-walk when we have target data available..
2550 if (LHS->getType()->isPointerTy())
2551 if (Constant *C = computePointerICmp(Q.TD, Q.TLI, Pred, LHS, RHS))
2554 if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
2555 if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
2556 if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
2557 GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
2558 (ICmpInst::isEquality(Pred) ||
2559 (GLHS->isInBounds() && GRHS->isInBounds() &&
2560 Pred == ICmpInst::getSignedPredicate(Pred)))) {
2561 // The bases are equal and the indices are constant. Build a constant
2562 // expression GEP with the same indices and a null base pointer to see
2563 // what constant folding can make out of it.
2564 Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
2565 SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
2566 Constant *NewLHS = ConstantExpr::getGetElementPtr(Null, IndicesLHS);
2568 SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
2569 Constant *NewRHS = ConstantExpr::getGetElementPtr(Null, IndicesRHS);
2570 return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
2575 // If the comparison is with the result of a select instruction, check whether
2576 // comparing with either branch of the select always yields the same value.
2577 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2578 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
2581 // If the comparison is with the result of a phi instruction, check whether
2582 // doing the compare with each incoming phi value yields a common result.
2583 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2584 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
2590 Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2591 const DataLayout *TD,
2592 const TargetLibraryInfo *TLI,
2593 const DominatorTree *DT) {
2594 return ::SimplifyICmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
2598 /// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can
2599 /// fold the result. If not, this returns null.
2600 static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2601 const Query &Q, unsigned MaxRecurse) {
2602 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
2603 assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
2605 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
2606 if (Constant *CRHS = dyn_cast<Constant>(RHS))
2607 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.TD, Q.TLI);
2609 // If we have a constant, make sure it is on the RHS.
2610 std::swap(LHS, RHS);
2611 Pred = CmpInst::getSwappedPredicate(Pred);
2614 // Fold trivial predicates.
2615 if (Pred == FCmpInst::FCMP_FALSE)
2616 return ConstantInt::get(GetCompareTy(LHS), 0);
2617 if (Pred == FCmpInst::FCMP_TRUE)
2618 return ConstantInt::get(GetCompareTy(LHS), 1);
2620 if (isa<UndefValue>(RHS)) // fcmp pred X, undef -> undef
2621 return UndefValue::get(GetCompareTy(LHS));
2623 // fcmp x,x -> true/false. Not all compares are foldable.
2625 if (CmpInst::isTrueWhenEqual(Pred))
2626 return ConstantInt::get(GetCompareTy(LHS), 1);
2627 if (CmpInst::isFalseWhenEqual(Pred))
2628 return ConstantInt::get(GetCompareTy(LHS), 0);
2631 // Handle fcmp with constant RHS
2632 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
2633 // If the constant is a nan, see if we can fold the comparison based on it.
2634 if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHSC)) {
2635 if (CFP->getValueAPF().isNaN()) {
2636 if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo"
2637 return ConstantInt::getFalse(CFP->getContext());
2638 assert(FCmpInst::isUnordered(Pred) &&
2639 "Comparison must be either ordered or unordered!");
2640 // True if unordered.
2641 return ConstantInt::getTrue(CFP->getContext());
2643 // Check whether the constant is an infinity.
2644 if (CFP->getValueAPF().isInfinity()) {
2645 if (CFP->getValueAPF().isNegative()) {
2647 case FCmpInst::FCMP_OLT:
2648 // No value is ordered and less than negative infinity.
2649 return ConstantInt::getFalse(CFP->getContext());
2650 case FCmpInst::FCMP_UGE:
2651 // All values are unordered with or at least negative infinity.
2652 return ConstantInt::getTrue(CFP->getContext());
2658 case FCmpInst::FCMP_OGT:
2659 // No value is ordered and greater than infinity.
2660 return ConstantInt::getFalse(CFP->getContext());
2661 case FCmpInst::FCMP_ULE:
2662 // All values are unordered with and at most infinity.
2663 return ConstantInt::getTrue(CFP->getContext());
2672 // If the comparison is with the result of a select instruction, check whether
2673 // comparing with either branch of the select always yields the same value.
2674 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2675 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
2678 // If the comparison is with the result of a phi instruction, check whether
2679 // doing the compare with each incoming phi value yields a common result.
2680 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2681 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
2687 Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2688 const DataLayout *TD,
2689 const TargetLibraryInfo *TLI,
2690 const DominatorTree *DT) {
2691 return ::SimplifyFCmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
2695 /// SimplifySelectInst - Given operands for a SelectInst, see if we can fold
2696 /// the result. If not, this returns null.
2697 static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal,
2698 Value *FalseVal, const Query &Q,
2699 unsigned MaxRecurse) {
2700 // select true, X, Y -> X
2701 // select false, X, Y -> Y
2702 if (ConstantInt *CB = dyn_cast<ConstantInt>(CondVal))
2703 return CB->getZExtValue() ? TrueVal : FalseVal;
2705 // select C, X, X -> X
2706 if (TrueVal == FalseVal)
2709 if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y
2710 if (isa<Constant>(TrueVal))
2714 if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X
2716 if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
2722 Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
2723 const DataLayout *TD,
2724 const TargetLibraryInfo *TLI,
2725 const DominatorTree *DT) {
2726 return ::SimplifySelectInst(Cond, TrueVal, FalseVal, Query (TD, TLI, DT),
2730 /// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
2731 /// fold the result. If not, this returns null.
2732 static Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const Query &Q, unsigned) {
2733 // The type of the GEP pointer operand.
2734 PointerType *PtrTy = dyn_cast<PointerType>(Ops[0]->getType());
2735 // The GEP pointer operand is not a pointer, it's a vector of pointers.
2739 // getelementptr P -> P.
2740 if (Ops.size() == 1)
2743 if (isa<UndefValue>(Ops[0])) {
2744 // Compute the (pointer) type returned by the GEP instruction.
2745 Type *LastType = GetElementPtrInst::getIndexedType(PtrTy, Ops.slice(1));
2746 Type *GEPTy = PointerType::get(LastType, PtrTy->getAddressSpace());
2747 return UndefValue::get(GEPTy);
2750 if (Ops.size() == 2) {
2751 // getelementptr P, 0 -> P.
2752 if (ConstantInt *C = dyn_cast<ConstantInt>(Ops[1]))
2755 // getelementptr P, N -> P if P points to a type of zero size.
2757 Type *Ty = PtrTy->getElementType();
2758 if (Ty->isSized() && Q.TD->getTypeAllocSize(Ty) == 0)
2763 // Check to see if this is constant foldable.
2764 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
2765 if (!isa<Constant>(Ops[i]))
2768 return ConstantExpr::getGetElementPtr(cast<Constant>(Ops[0]), Ops.slice(1));
2771 Value *llvm::SimplifyGEPInst(ArrayRef<Value *> Ops, const DataLayout *TD,
2772 const TargetLibraryInfo *TLI,
2773 const DominatorTree *DT) {
2774 return ::SimplifyGEPInst(Ops, Query (TD, TLI, DT), RecursionLimit);
2777 /// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we
2778 /// can fold the result. If not, this returns null.
2779 static Value *SimplifyInsertValueInst(Value *Agg, Value *Val,
2780 ArrayRef<unsigned> Idxs, const Query &Q,
2782 if (Constant *CAgg = dyn_cast<Constant>(Agg))
2783 if (Constant *CVal = dyn_cast<Constant>(Val))
2784 return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
2786 // insertvalue x, undef, n -> x
2787 if (match(Val, m_Undef()))
2790 // insertvalue x, (extractvalue y, n), n
2791 if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
2792 if (EV->getAggregateOperand()->getType() == Agg->getType() &&
2793 EV->getIndices() == Idxs) {
2794 // insertvalue undef, (extractvalue y, n), n -> y
2795 if (match(Agg, m_Undef()))
2796 return EV->getAggregateOperand();
2798 // insertvalue y, (extractvalue y, n), n -> y
2799 if (Agg == EV->getAggregateOperand())
2806 Value *llvm::SimplifyInsertValueInst(Value *Agg, Value *Val,
2807 ArrayRef<unsigned> Idxs,
2808 const DataLayout *TD,
2809 const TargetLibraryInfo *TLI,
2810 const DominatorTree *DT) {
2811 return ::SimplifyInsertValueInst(Agg, Val, Idxs, Query (TD, TLI, DT),
2815 /// SimplifyPHINode - See if we can fold the given phi. If not, returns null.
2816 static Value *SimplifyPHINode(PHINode *PN, const Query &Q) {
2817 // If all of the PHI's incoming values are the same then replace the PHI node
2818 // with the common value.
2819 Value *CommonValue = 0;
2820 bool HasUndefInput = false;
2821 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
2822 Value *Incoming = PN->getIncomingValue(i);
2823 // If the incoming value is the phi node itself, it can safely be skipped.
2824 if (Incoming == PN) continue;
2825 if (isa<UndefValue>(Incoming)) {
2826 // Remember that we saw an undef value, but otherwise ignore them.
2827 HasUndefInput = true;
2830 if (CommonValue && Incoming != CommonValue)
2831 return 0; // Not the same, bail out.
2832 CommonValue = Incoming;
2835 // If CommonValue is null then all of the incoming values were either undef or
2836 // equal to the phi node itself.
2838 return UndefValue::get(PN->getType());
2840 // If we have a PHI node like phi(X, undef, X), where X is defined by some
2841 // instruction, we cannot return X as the result of the PHI node unless it
2842 // dominates the PHI block.
2844 return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : 0;
2849 static Value *SimplifyTruncInst(Value *Op, Type *Ty, const Query &Q, unsigned) {
2850 if (Constant *C = dyn_cast<Constant>(Op))
2851 return ConstantFoldInstOperands(Instruction::Trunc, Ty, C, Q.TD, Q.TLI);
2856 Value *llvm::SimplifyTruncInst(Value *Op, Type *Ty, const DataLayout *TD,
2857 const TargetLibraryInfo *TLI,
2858 const DominatorTree *DT) {
2859 return ::SimplifyTruncInst(Op, Ty, Query (TD, TLI, DT), RecursionLimit);
2862 //=== Helper functions for higher up the class hierarchy.
2864 /// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
2865 /// fold the result. If not, this returns null.
2866 static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
2867 const Query &Q, unsigned MaxRecurse) {
2869 case Instruction::Add:
2870 return SimplifyAddInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2872 case Instruction::FAdd:
2873 return SimplifyFAddInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
2875 case Instruction::Sub:
2876 return SimplifySubInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2878 case Instruction::FSub:
2879 return SimplifyFSubInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
2881 case Instruction::Mul: return SimplifyMulInst (LHS, RHS, Q, MaxRecurse);
2882 case Instruction::FMul:
2883 return SimplifyFMulInst (LHS, RHS, FastMathFlags(), Q, MaxRecurse);
2884 case Instruction::SDiv: return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
2885 case Instruction::UDiv: return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
2886 case Instruction::FDiv: return SimplifyFDivInst(LHS, RHS, Q, MaxRecurse);
2887 case Instruction::SRem: return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
2888 case Instruction::URem: return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
2889 case Instruction::FRem: return SimplifyFRemInst(LHS, RHS, Q, MaxRecurse);
2890 case Instruction::Shl:
2891 return SimplifyShlInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2893 case Instruction::LShr:
2894 return SimplifyLShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
2895 case Instruction::AShr:
2896 return SimplifyAShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
2897 case Instruction::And: return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
2898 case Instruction::Or: return SimplifyOrInst (LHS, RHS, Q, MaxRecurse);
2899 case Instruction::Xor: return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
2901 if (Constant *CLHS = dyn_cast<Constant>(LHS))
2902 if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
2903 Constant *COps[] = {CLHS, CRHS};
2904 return ConstantFoldInstOperands(Opcode, LHS->getType(), COps, Q.TD,
2908 // If the operation is associative, try some generic simplifications.
2909 if (Instruction::isAssociative(Opcode))
2910 if (Value *V = SimplifyAssociativeBinOp(Opcode, LHS, RHS, Q, MaxRecurse))
2913 // If the operation is with the result of a select instruction check whether
2914 // operating on either branch of the select always yields the same value.
2915 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2916 if (Value *V = ThreadBinOpOverSelect(Opcode, LHS, RHS, Q, MaxRecurse))
2919 // If the operation is with the result of a phi instruction, check whether
2920 // operating on all incoming values of the phi always yields the same value.
2921 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2922 if (Value *V = ThreadBinOpOverPHI(Opcode, LHS, RHS, Q, MaxRecurse))
2929 Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
2930 const DataLayout *TD, const TargetLibraryInfo *TLI,
2931 const DominatorTree *DT) {
2932 return ::SimplifyBinOp(Opcode, LHS, RHS, Query (TD, TLI, DT), RecursionLimit);
2935 /// SimplifyCmpInst - Given operands for a CmpInst, see if we can
2936 /// fold the result.
2937 static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2938 const Query &Q, unsigned MaxRecurse) {
2939 if (CmpInst::isIntPredicate((CmpInst::Predicate)Predicate))
2940 return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
2941 return SimplifyFCmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
2944 Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2945 const DataLayout *TD, const TargetLibraryInfo *TLI,
2946 const DominatorTree *DT) {
2947 return ::SimplifyCmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
2951 static bool IsIdempotent(Intrinsic::ID ID) {
2953 default: return false;
2955 // Unary idempotent: f(f(x)) = f(x)
2956 case Intrinsic::fabs:
2957 case Intrinsic::floor:
2958 case Intrinsic::ceil:
2959 case Intrinsic::trunc:
2960 case Intrinsic::rint:
2961 case Intrinsic::nearbyint:
2962 case Intrinsic::round:
2967 template <typename IterTy>
2968 static Value *SimplifyIntrinsic(Intrinsic::ID IID, IterTy ArgBegin, IterTy ArgEnd,
2969 const Query &Q, unsigned MaxRecurse) {
2970 // Perform idempotent optimizations
2971 if (!IsIdempotent(IID))
2975 if (std::distance(ArgBegin, ArgEnd) == 1)
2976 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(*ArgBegin))
2977 if (II->getIntrinsicID() == IID)
2983 template <typename IterTy>
2984 static Value *SimplifyCall(Value *V, IterTy ArgBegin, IterTy ArgEnd,
2985 const Query &Q, unsigned MaxRecurse) {
2986 Type *Ty = V->getType();
2987 if (PointerType *PTy = dyn_cast<PointerType>(Ty))
2988 Ty = PTy->getElementType();
2989 FunctionType *FTy = cast<FunctionType>(Ty);
2991 // call undef -> undef
2992 if (isa<UndefValue>(V))
2993 return UndefValue::get(FTy->getReturnType());
2995 Function *F = dyn_cast<Function>(V);
2999 if (unsigned IID = F->getIntrinsicID())
3001 SimplifyIntrinsic((Intrinsic::ID) IID, ArgBegin, ArgEnd, Q, MaxRecurse))
3004 if (!canConstantFoldCallTo(F))
3007 SmallVector<Constant *, 4> ConstantArgs;
3008 ConstantArgs.reserve(ArgEnd - ArgBegin);
3009 for (IterTy I = ArgBegin, E = ArgEnd; I != E; ++I) {
3010 Constant *C = dyn_cast<Constant>(*I);
3013 ConstantArgs.push_back(C);
3016 return ConstantFoldCall(F, ConstantArgs, Q.TLI);
3019 Value *llvm::SimplifyCall(Value *V, User::op_iterator ArgBegin,
3020 User::op_iterator ArgEnd, const DataLayout *TD,
3021 const TargetLibraryInfo *TLI,
3022 const DominatorTree *DT) {
3023 return ::SimplifyCall(V, ArgBegin, ArgEnd, Query(TD, TLI, DT),
3027 Value *llvm::SimplifyCall(Value *V, ArrayRef<Value *> Args,
3028 const DataLayout *TD, const TargetLibraryInfo *TLI,
3029 const DominatorTree *DT) {
3030 return ::SimplifyCall(V, Args.begin(), Args.end(), Query(TD, TLI, DT),
3034 /// SimplifyInstruction - See if we can compute a simplified version of this
3035 /// instruction. If not, this returns null.
3036 Value *llvm::SimplifyInstruction(Instruction *I, const DataLayout *TD,
3037 const TargetLibraryInfo *TLI,
3038 const DominatorTree *DT) {
3041 switch (I->getOpcode()) {
3043 Result = ConstantFoldInstruction(I, TD, TLI);
3045 case Instruction::FAdd:
3046 Result = SimplifyFAddInst(I->getOperand(0), I->getOperand(1),
3047 I->getFastMathFlags(), TD, TLI, DT);
3049 case Instruction::Add:
3050 Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
3051 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3052 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3055 case Instruction::FSub:
3056 Result = SimplifyFSubInst(I->getOperand(0), I->getOperand(1),
3057 I->getFastMathFlags(), TD, TLI, DT);
3059 case Instruction::Sub:
3060 Result = SimplifySubInst(I->getOperand(0), I->getOperand(1),
3061 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3062 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3065 case Instruction::FMul:
3066 Result = SimplifyFMulInst(I->getOperand(0), I->getOperand(1),
3067 I->getFastMathFlags(), TD, TLI, DT);
3069 case Instruction::Mul:
3070 Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3072 case Instruction::SDiv:
3073 Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3075 case Instruction::UDiv:
3076 Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3078 case Instruction::FDiv:
3079 Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3081 case Instruction::SRem:
3082 Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3084 case Instruction::URem:
3085 Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3087 case Instruction::FRem:
3088 Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3090 case Instruction::Shl:
3091 Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1),
3092 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3093 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3096 case Instruction::LShr:
3097 Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
3098 cast<BinaryOperator>(I)->isExact(),
3101 case Instruction::AShr:
3102 Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
3103 cast<BinaryOperator>(I)->isExact(),
3106 case Instruction::And:
3107 Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3109 case Instruction::Or:
3110 Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3112 case Instruction::Xor:
3113 Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3115 case Instruction::ICmp:
3116 Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
3117 I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3119 case Instruction::FCmp:
3120 Result = SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(),
3121 I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3123 case Instruction::Select:
3124 Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
3125 I->getOperand(2), TD, TLI, DT);
3127 case Instruction::GetElementPtr: {
3128 SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end());
3129 Result = SimplifyGEPInst(Ops, TD, TLI, DT);
3132 case Instruction::InsertValue: {
3133 InsertValueInst *IV = cast<InsertValueInst>(I);
3134 Result = SimplifyInsertValueInst(IV->getAggregateOperand(),
3135 IV->getInsertedValueOperand(),
3136 IV->getIndices(), TD, TLI, DT);
3139 case Instruction::PHI:
3140 Result = SimplifyPHINode(cast<PHINode>(I), Query (TD, TLI, DT));
3142 case Instruction::Call: {
3143 CallSite CS(cast<CallInst>(I));
3144 Result = SimplifyCall(CS.getCalledValue(), CS.arg_begin(), CS.arg_end(),
3148 case Instruction::Trunc:
3149 Result = SimplifyTruncInst(I->getOperand(0), I->getType(), TD, TLI, DT);
3153 /// If called on unreachable code, the above logic may report that the
3154 /// instruction simplified to itself. Make life easier for users by
3155 /// detecting that case here, returning a safe value instead.
3156 return Result == I ? UndefValue::get(I->getType()) : Result;
3159 /// \brief Implementation of recursive simplification through an instructions
3162 /// This is the common implementation of the recursive simplification routines.
3163 /// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
3164 /// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
3165 /// instructions to process and attempt to simplify it using
3166 /// InstructionSimplify.
3168 /// This routine returns 'true' only when *it* simplifies something. The passed
3169 /// in simplified value does not count toward this.
3170 static bool replaceAndRecursivelySimplifyImpl(Instruction *I, Value *SimpleV,
3171 const DataLayout *TD,
3172 const TargetLibraryInfo *TLI,
3173 const DominatorTree *DT) {
3174 bool Simplified = false;
3175 SmallSetVector<Instruction *, 8> Worklist;
3177 // If we have an explicit value to collapse to, do that round of the
3178 // simplification loop by hand initially.
3180 for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE;
3183 Worklist.insert(cast<Instruction>(*UI));
3185 // Replace the instruction with its simplified value.
3186 I->replaceAllUsesWith(SimpleV);
3188 // Gracefully handle edge cases where the instruction is not wired into any
3191 I->eraseFromParent();
3196 // Note that we must test the size on each iteration, the worklist can grow.
3197 for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
3200 // See if this instruction simplifies.
3201 SimpleV = SimplifyInstruction(I, TD, TLI, DT);
3207 // Stash away all the uses of the old instruction so we can check them for
3208 // recursive simplifications after a RAUW. This is cheaper than checking all
3209 // uses of To on the recursive step in most cases.
3210 for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE;
3212 Worklist.insert(cast<Instruction>(*UI));
3214 // Replace the instruction with its simplified value.
3215 I->replaceAllUsesWith(SimpleV);
3217 // Gracefully handle edge cases where the instruction is not wired into any
3220 I->eraseFromParent();
3225 bool llvm::recursivelySimplifyInstruction(Instruction *I,
3226 const DataLayout *TD,
3227 const TargetLibraryInfo *TLI,
3228 const DominatorTree *DT) {
3229 return replaceAndRecursivelySimplifyImpl(I, 0, TD, TLI, DT);
3232 bool llvm::replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV,
3233 const DataLayout *TD,
3234 const TargetLibraryInfo *TLI,
3235 const DominatorTree *DT) {
3236 assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!");
3237 assert(SimpleV && "Must provide a simplified value.");
3238 return replaceAndRecursivelySimplifyImpl(I, SimpleV, TD, TLI, DT);