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 assert(V->getType()->getScalarType()->isPointerTy());
674 // Without DataLayout, just be conservative for now. Theoretically, more could
675 // be done in this case.
677 return ConstantInt::get(IntegerType::get(V->getContext(), 64), 0);
679 Type *IntPtrTy = TD->getIntPtrType(V->getType())->getScalarType();
680 APInt Offset = APInt::getNullValue(IntPtrTy->getIntegerBitWidth());
682 // Even though we don't look through PHI nodes, we could be called on an
683 // instruction in an unreachable block, which may be on a cycle.
684 SmallPtrSet<Value *, 4> Visited;
687 if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
688 if (!GEP->isInBounds() || !GEP->accumulateConstantOffset(*TD, Offset))
690 V = GEP->getPointerOperand();
691 } else if (Operator::getOpcode(V) == Instruction::BitCast) {
692 V = cast<Operator>(V)->getOperand(0);
693 } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
694 if (GA->mayBeOverridden())
696 V = GA->getAliasee();
700 assert(V->getType()->getScalarType()->isPointerTy() &&
701 "Unexpected operand type!");
702 } while (Visited.insert(V));
704 Constant *OffsetIntPtr = ConstantInt::get(IntPtrTy, Offset);
705 if (V->getType()->isVectorTy())
706 return ConstantVector::getSplat(V->getType()->getVectorNumElements(),
711 /// \brief Compute the constant difference between two pointer values.
712 /// If the difference is not a constant, returns zero.
713 static Constant *computePointerDifference(const DataLayout *TD,
714 Value *LHS, Value *RHS) {
715 Constant *LHSOffset = stripAndComputeConstantOffsets(TD, LHS);
716 Constant *RHSOffset = stripAndComputeConstantOffsets(TD, RHS);
718 // If LHS and RHS are not related via constant offsets to the same base
719 // value, there is nothing we can do here.
723 // Otherwise, the difference of LHS - RHS can be computed as:
725 // = (LHSOffset + Base) - (RHSOffset + Base)
726 // = LHSOffset - RHSOffset
727 return ConstantExpr::getSub(LHSOffset, RHSOffset);
730 /// SimplifySubInst - Given operands for a Sub, see if we can
731 /// fold the result. If not, this returns null.
732 static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
733 const Query &Q, unsigned MaxRecurse) {
734 if (Constant *CLHS = dyn_cast<Constant>(Op0))
735 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
736 Constant *Ops[] = { CLHS, CRHS };
737 return ConstantFoldInstOperands(Instruction::Sub, CLHS->getType(),
741 // X - undef -> undef
742 // undef - X -> undef
743 if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
744 return UndefValue::get(Op0->getType());
747 if (match(Op1, m_Zero()))
752 return Constant::getNullValue(Op0->getType());
757 if (match(Op0, m_Mul(m_Specific(Op1), m_ConstantInt<2>())) ||
758 match(Op0, m_Shl(m_Specific(Op1), m_One())))
761 // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
762 // For example, (X + Y) - Y -> X; (Y + X) - Y -> X
763 Value *Y = 0, *Z = Op1;
764 if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z
765 // See if "V === Y - Z" simplifies.
766 if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, Q, MaxRecurse-1))
767 // It does! Now see if "X + V" simplifies.
768 if (Value *W = SimplifyBinOp(Instruction::Add, X, V, Q, MaxRecurse-1)) {
769 // It does, we successfully reassociated!
773 // See if "V === X - Z" simplifies.
774 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
775 // It does! Now see if "Y + V" simplifies.
776 if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, Q, MaxRecurse-1)) {
777 // It does, we successfully reassociated!
783 // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
784 // For example, X - (X + 1) -> -1
786 if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z)
787 // See if "V === X - Y" simplifies.
788 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
789 // It does! Now see if "V - Z" simplifies.
790 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, Q, MaxRecurse-1)) {
791 // It does, we successfully reassociated!
795 // See if "V === X - Z" simplifies.
796 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
797 // It does! Now see if "V - Y" simplifies.
798 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, Q, MaxRecurse-1)) {
799 // It does, we successfully reassociated!
805 // Z - (X - Y) -> (Z - X) + Y if everything simplifies.
806 // For example, X - (X - Y) -> Y.
808 if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y)
809 // See if "V === Z - X" simplifies.
810 if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, Q, MaxRecurse-1))
811 // It does! Now see if "V + Y" simplifies.
812 if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, Q, MaxRecurse-1)) {
813 // It does, we successfully reassociated!
818 // trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies.
819 if (MaxRecurse && match(Op0, m_Trunc(m_Value(X))) &&
820 match(Op1, m_Trunc(m_Value(Y))))
821 if (X->getType() == Y->getType())
822 // See if "V === X - Y" simplifies.
823 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
824 // It does! Now see if "trunc V" simplifies.
825 if (Value *W = SimplifyTruncInst(V, Op0->getType(), Q, MaxRecurse-1))
826 // It does, return the simplified "trunc V".
829 // Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...).
830 if (match(Op0, m_PtrToInt(m_Value(X))) &&
831 match(Op1, m_PtrToInt(m_Value(Y))))
832 if (Constant *Result = computePointerDifference(Q.TD, X, Y))
833 return ConstantExpr::getIntegerCast(Result, Op0->getType(), true);
835 // Mul distributes over Sub. Try some generic simplifications based on this.
836 if (Value *V = FactorizeBinOp(Instruction::Sub, Op0, Op1, Instruction::Mul,
841 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
842 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
845 // Threading Sub over selects and phi nodes is pointless, so don't bother.
846 // Threading over the select in "A - select(cond, B, C)" means evaluating
847 // "A-B" and "A-C" and seeing if they are equal; but they are equal if and
848 // only if B and C are equal. If B and C are equal then (since we assume
849 // that operands have already been simplified) "select(cond, B, C)" should
850 // have been simplified to the common value of B and C already. Analysing
851 // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly
852 // for threading over phi nodes.
857 Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
858 const DataLayout *TD, const TargetLibraryInfo *TLI,
859 const DominatorTree *DT) {
860 return ::SimplifySubInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT),
864 /// Given operands for an FAdd, see if we can fold the result. If not, this
866 static Value *SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
867 const Query &Q, unsigned MaxRecurse) {
868 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
869 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
870 Constant *Ops[] = { CLHS, CRHS };
871 return ConstantFoldInstOperands(Instruction::FAdd, CLHS->getType(),
875 // Canonicalize the constant to the RHS.
880 if (match(Op1, m_NegZero()))
883 // fadd X, 0 ==> X, when we know X is not -0
884 if (match(Op1, m_Zero()) &&
885 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
888 // fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
889 // where nnan and ninf have to occur at least once somewhere in this
892 if (match(Op1, m_FSub(m_AnyZero(), m_Specific(Op0))))
894 else if (match(Op0, m_FSub(m_AnyZero(), m_Specific(Op1))))
897 Instruction *FSub = cast<Instruction>(SubOp);
898 if ((FMF.noNaNs() || FSub->hasNoNaNs()) &&
899 (FMF.noInfs() || FSub->hasNoInfs()))
900 return Constant::getNullValue(Op0->getType());
906 /// Given operands for an FSub, see if we can fold the result. If not, this
908 static Value *SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
909 const Query &Q, unsigned MaxRecurse) {
910 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
911 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
912 Constant *Ops[] = { CLHS, CRHS };
913 return ConstantFoldInstOperands(Instruction::FSub, CLHS->getType(),
919 if (match(Op1, m_Zero()))
922 // fsub X, -0 ==> X, when we know X is not -0
923 if (match(Op1, m_NegZero()) &&
924 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
927 // fsub 0, (fsub -0.0, X) ==> X
929 if (match(Op0, m_AnyZero())) {
930 if (match(Op1, m_FSub(m_NegZero(), m_Value(X))))
932 if (FMF.noSignedZeros() && match(Op1, m_FSub(m_AnyZero(), m_Value(X))))
936 // fsub nnan ninf x, x ==> 0.0
937 if (FMF.noNaNs() && FMF.noInfs() && Op0 == Op1)
938 return Constant::getNullValue(Op0->getType());
943 /// Given the operands for an FMul, see if we can fold the result
944 static Value *SimplifyFMulInst(Value *Op0, Value *Op1,
947 unsigned MaxRecurse) {
948 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
949 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
950 Constant *Ops[] = { CLHS, CRHS };
951 return ConstantFoldInstOperands(Instruction::FMul, CLHS->getType(),
955 // Canonicalize the constant to the RHS.
960 if (match(Op1, m_FPOne()))
963 // fmul nnan nsz X, 0 ==> 0
964 if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZero()))
970 /// SimplifyMulInst - Given operands for a Mul, see if we can
971 /// fold the result. If not, this returns null.
972 static Value *SimplifyMulInst(Value *Op0, Value *Op1, const Query &Q,
973 unsigned MaxRecurse) {
974 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
975 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
976 Constant *Ops[] = { CLHS, CRHS };
977 return ConstantFoldInstOperands(Instruction::Mul, CLHS->getType(),
981 // Canonicalize the constant to the RHS.
986 if (match(Op1, m_Undef()))
987 return Constant::getNullValue(Op0->getType());
990 if (match(Op1, m_Zero()))
994 if (match(Op1, m_One()))
997 // (X / Y) * Y -> X if the division is exact.
999 if (match(Op0, m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y
1000 match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0))))) // Y * (X / Y)
1004 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
1005 if (Value *V = SimplifyAndInst(Op0, Op1, Q, MaxRecurse-1))
1008 // Try some generic simplifications for associative operations.
1009 if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, Q,
1013 // Mul distributes over Add. Try some generic simplifications based on this.
1014 if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add,
1018 // If the operation is with the result of a select instruction, check whether
1019 // operating on either branch of the select always yields the same value.
1020 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1021 if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, Q,
1025 // If the operation is with the result of a phi instruction, check whether
1026 // operating on all incoming values of the phi always yields the same value.
1027 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1028 if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, Q,
1035 Value *llvm::SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
1036 const DataLayout *TD, const TargetLibraryInfo *TLI,
1037 const DominatorTree *DT) {
1038 return ::SimplifyFAddInst(Op0, Op1, FMF, Query (TD, TLI, DT), RecursionLimit);
1041 Value *llvm::SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
1042 const DataLayout *TD, const TargetLibraryInfo *TLI,
1043 const DominatorTree *DT) {
1044 return ::SimplifyFSubInst(Op0, Op1, FMF, Query (TD, TLI, DT), RecursionLimit);
1047 Value *llvm::SimplifyFMulInst(Value *Op0, Value *Op1,
1049 const DataLayout *TD,
1050 const TargetLibraryInfo *TLI,
1051 const DominatorTree *DT) {
1052 return ::SimplifyFMulInst(Op0, Op1, FMF, Query (TD, TLI, DT), RecursionLimit);
1055 Value *llvm::SimplifyMulInst(Value *Op0, Value *Op1, const DataLayout *TD,
1056 const TargetLibraryInfo *TLI,
1057 const DominatorTree *DT) {
1058 return ::SimplifyMulInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1061 /// SimplifyDiv - Given operands for an SDiv or UDiv, see if we can
1062 /// fold the result. If not, this returns null.
1063 static Value *SimplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
1064 const Query &Q, unsigned MaxRecurse) {
1065 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1066 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1067 Constant *Ops[] = { C0, C1 };
1068 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI);
1072 bool isSigned = Opcode == Instruction::SDiv;
1074 // X / undef -> undef
1075 if (match(Op1, m_Undef()))
1079 if (match(Op0, m_Undef()))
1080 return Constant::getNullValue(Op0->getType());
1082 // 0 / X -> 0, we don't need to preserve faults!
1083 if (match(Op0, m_Zero()))
1087 if (match(Op1, m_One()))
1090 if (Op0->getType()->isIntegerTy(1))
1091 // It can't be division by zero, hence it must be division by one.
1096 return ConstantInt::get(Op0->getType(), 1);
1098 // (X * Y) / Y -> X if the multiplication does not overflow.
1099 Value *X = 0, *Y = 0;
1100 if (match(Op0, m_Mul(m_Value(X), m_Value(Y))) && (X == Op1 || Y == Op1)) {
1101 if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1
1102 OverflowingBinaryOperator *Mul = cast<OverflowingBinaryOperator>(Op0);
1103 // If the Mul knows it does not overflow, then we are good to go.
1104 if ((isSigned && Mul->hasNoSignedWrap()) ||
1105 (!isSigned && Mul->hasNoUnsignedWrap()))
1107 // If X has the form X = A / Y then X * Y cannot overflow.
1108 if (BinaryOperator *Div = dyn_cast<BinaryOperator>(X))
1109 if (Div->getOpcode() == Opcode && Div->getOperand(1) == Y)
1113 // (X rem Y) / Y -> 0
1114 if ((isSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1115 (!isSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1116 return Constant::getNullValue(Op0->getType());
1118 // If the operation is with the result of a select instruction, check whether
1119 // operating on either branch of the select always yields the same value.
1120 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1121 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1124 // If the operation is with the result of a phi instruction, check whether
1125 // operating on all incoming values of the phi always yields the same value.
1126 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1127 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1133 /// SimplifySDivInst - Given operands for an SDiv, see if we can
1134 /// fold the result. If not, this returns null.
1135 static Value *SimplifySDivInst(Value *Op0, Value *Op1, const Query &Q,
1136 unsigned MaxRecurse) {
1137 if (Value *V = SimplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse))
1143 Value *llvm::SimplifySDivInst(Value *Op0, Value *Op1, const DataLayout *TD,
1144 const TargetLibraryInfo *TLI,
1145 const DominatorTree *DT) {
1146 return ::SimplifySDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1149 /// SimplifyUDivInst - Given operands for a UDiv, see if we can
1150 /// fold the result. If not, this returns null.
1151 static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const Query &Q,
1152 unsigned MaxRecurse) {
1153 if (Value *V = SimplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse))
1159 Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const DataLayout *TD,
1160 const TargetLibraryInfo *TLI,
1161 const DominatorTree *DT) {
1162 return ::SimplifyUDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1165 static Value *SimplifyFDivInst(Value *Op0, Value *Op1, const Query &Q,
1167 // undef / X -> undef (the undef could be a snan).
1168 if (match(Op0, m_Undef()))
1171 // X / undef -> undef
1172 if (match(Op1, m_Undef()))
1178 Value *llvm::SimplifyFDivInst(Value *Op0, Value *Op1, const DataLayout *TD,
1179 const TargetLibraryInfo *TLI,
1180 const DominatorTree *DT) {
1181 return ::SimplifyFDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1184 /// SimplifyRem - Given operands for an SRem or URem, see if we can
1185 /// fold the result. If not, this returns null.
1186 static Value *SimplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
1187 const Query &Q, unsigned MaxRecurse) {
1188 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1189 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1190 Constant *Ops[] = { C0, C1 };
1191 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI);
1195 // X % undef -> undef
1196 if (match(Op1, m_Undef()))
1200 if (match(Op0, m_Undef()))
1201 return Constant::getNullValue(Op0->getType());
1203 // 0 % X -> 0, we don't need to preserve faults!
1204 if (match(Op0, m_Zero()))
1207 // X % 0 -> undef, we don't need to preserve faults!
1208 if (match(Op1, m_Zero()))
1209 return UndefValue::get(Op0->getType());
1212 if (match(Op1, m_One()))
1213 return Constant::getNullValue(Op0->getType());
1215 if (Op0->getType()->isIntegerTy(1))
1216 // It can't be remainder by zero, hence it must be remainder by one.
1217 return Constant::getNullValue(Op0->getType());
1221 return Constant::getNullValue(Op0->getType());
1223 // If the operation is with the result of a select instruction, check whether
1224 // operating on either branch of the select always yields the same value.
1225 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1226 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1229 // If the operation is with the result of a phi instruction, check whether
1230 // operating on all incoming values of the phi always yields the same value.
1231 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1232 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1238 /// SimplifySRemInst - Given operands for an SRem, see if we can
1239 /// fold the result. If not, this returns null.
1240 static Value *SimplifySRemInst(Value *Op0, Value *Op1, const Query &Q,
1241 unsigned MaxRecurse) {
1242 if (Value *V = SimplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse))
1248 Value *llvm::SimplifySRemInst(Value *Op0, Value *Op1, const DataLayout *TD,
1249 const TargetLibraryInfo *TLI,
1250 const DominatorTree *DT) {
1251 return ::SimplifySRemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1254 /// SimplifyURemInst - Given operands for a URem, see if we can
1255 /// fold the result. If not, this returns null.
1256 static Value *SimplifyURemInst(Value *Op0, Value *Op1, const Query &Q,
1257 unsigned MaxRecurse) {
1258 if (Value *V = SimplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse))
1264 Value *llvm::SimplifyURemInst(Value *Op0, Value *Op1, const DataLayout *TD,
1265 const TargetLibraryInfo *TLI,
1266 const DominatorTree *DT) {
1267 return ::SimplifyURemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1270 static Value *SimplifyFRemInst(Value *Op0, Value *Op1, const Query &,
1272 // undef % X -> undef (the undef could be a snan).
1273 if (match(Op0, m_Undef()))
1276 // X % undef -> undef
1277 if (match(Op1, m_Undef()))
1283 Value *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, const DataLayout *TD,
1284 const TargetLibraryInfo *TLI,
1285 const DominatorTree *DT) {
1286 return ::SimplifyFRemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1289 /// SimplifyShift - Given operands for an Shl, LShr or AShr, see if we can
1290 /// fold the result. If not, this returns null.
1291 static Value *SimplifyShift(unsigned Opcode, Value *Op0, Value *Op1,
1292 const Query &Q, unsigned MaxRecurse) {
1293 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1294 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1295 Constant *Ops[] = { C0, C1 };
1296 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI);
1300 // 0 shift by X -> 0
1301 if (match(Op0, m_Zero()))
1304 // X shift by 0 -> X
1305 if (match(Op1, m_Zero()))
1308 // X shift by undef -> undef because it may shift by the bitwidth.
1309 if (match(Op1, m_Undef()))
1312 // Shifting by the bitwidth or more is undefined.
1313 if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1))
1314 if (CI->getValue().getLimitedValue() >=
1315 Op0->getType()->getScalarSizeInBits())
1316 return UndefValue::get(Op0->getType());
1318 // If the operation is with the result of a select instruction, check whether
1319 // operating on either branch of the select always yields the same value.
1320 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1321 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1324 // If the operation is with the result of a phi instruction, check whether
1325 // operating on all incoming values of the phi always yields the same value.
1326 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1327 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1333 /// SimplifyShlInst - Given operands for an Shl, see if we can
1334 /// fold the result. If not, this returns null.
1335 static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1336 const Query &Q, unsigned MaxRecurse) {
1337 if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse))
1341 if (match(Op0, m_Undef()))
1342 return Constant::getNullValue(Op0->getType());
1344 // (X >> A) << A -> X
1346 if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
1351 Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1352 const DataLayout *TD, const TargetLibraryInfo *TLI,
1353 const DominatorTree *DT) {
1354 return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT),
1358 /// SimplifyLShrInst - Given operands for an LShr, see if we can
1359 /// fold the result. If not, this returns null.
1360 static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1361 const Query &Q, unsigned MaxRecurse) {
1362 if (Value *V = SimplifyShift(Instruction::LShr, Op0, Op1, Q, MaxRecurse))
1367 return Constant::getNullValue(Op0->getType());
1370 if (match(Op0, m_Undef()))
1371 return Constant::getNullValue(Op0->getType());
1373 // (X << A) >> A -> X
1375 if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) &&
1376 cast<OverflowingBinaryOperator>(Op0)->hasNoUnsignedWrap())
1382 Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1383 const DataLayout *TD,
1384 const TargetLibraryInfo *TLI,
1385 const DominatorTree *DT) {
1386 return ::SimplifyLShrInst(Op0, Op1, isExact, Query (TD, TLI, DT),
1390 /// SimplifyAShrInst - Given operands for an AShr, see if we can
1391 /// fold the result. If not, this returns null.
1392 static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1393 const Query &Q, unsigned MaxRecurse) {
1394 if (Value *V = SimplifyShift(Instruction::AShr, Op0, Op1, Q, MaxRecurse))
1399 return Constant::getNullValue(Op0->getType());
1401 // all ones >>a X -> all ones
1402 if (match(Op0, m_AllOnes()))
1405 // undef >>a X -> all ones
1406 if (match(Op0, m_Undef()))
1407 return Constant::getAllOnesValue(Op0->getType());
1409 // (X << A) >> A -> X
1411 if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) &&
1412 cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap())
1418 Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1419 const DataLayout *TD,
1420 const TargetLibraryInfo *TLI,
1421 const DominatorTree *DT) {
1422 return ::SimplifyAShrInst(Op0, Op1, isExact, Query (TD, TLI, DT),
1426 /// SimplifyAndInst - Given operands for an And, see if we can
1427 /// fold the result. If not, this returns null.
1428 static Value *SimplifyAndInst(Value *Op0, Value *Op1, const Query &Q,
1429 unsigned MaxRecurse) {
1430 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1431 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1432 Constant *Ops[] = { CLHS, CRHS };
1433 return ConstantFoldInstOperands(Instruction::And, CLHS->getType(),
1437 // Canonicalize the constant to the RHS.
1438 std::swap(Op0, Op1);
1442 if (match(Op1, m_Undef()))
1443 return Constant::getNullValue(Op0->getType());
1450 if (match(Op1, m_Zero()))
1454 if (match(Op1, m_AllOnes()))
1457 // A & ~A = ~A & A = 0
1458 if (match(Op0, m_Not(m_Specific(Op1))) ||
1459 match(Op1, m_Not(m_Specific(Op0))))
1460 return Constant::getNullValue(Op0->getType());
1463 Value *A = 0, *B = 0;
1464 if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
1465 (A == Op1 || B == Op1))
1469 if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
1470 (A == Op0 || B == Op0))
1473 // A & (-A) = A if A is a power of two or zero.
1474 if (match(Op0, m_Neg(m_Specific(Op1))) ||
1475 match(Op1, m_Neg(m_Specific(Op0)))) {
1476 if (isKnownToBeAPowerOfTwo(Op0, /*OrZero*/true))
1478 if (isKnownToBeAPowerOfTwo(Op1, /*OrZero*/true))
1482 // Try some generic simplifications for associative operations.
1483 if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
1487 // And distributes over Or. Try some generic simplifications based on this.
1488 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1492 // And distributes over Xor. Try some generic simplifications based on this.
1493 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
1497 // Or distributes over And. Try some generic simplifications based on this.
1498 if (Value *V = FactorizeBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1502 // If the operation is with the result of a select instruction, check whether
1503 // operating on either branch of the select always yields the same value.
1504 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1505 if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
1509 // If the operation is with the result of a phi instruction, check whether
1510 // operating on all incoming values of the phi always yields the same value.
1511 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1512 if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
1519 Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const DataLayout *TD,
1520 const TargetLibraryInfo *TLI,
1521 const DominatorTree *DT) {
1522 return ::SimplifyAndInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1525 /// SimplifyOrInst - Given operands for an Or, see if we can
1526 /// fold the result. If not, this returns null.
1527 static Value *SimplifyOrInst(Value *Op0, Value *Op1, const Query &Q,
1528 unsigned MaxRecurse) {
1529 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1530 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1531 Constant *Ops[] = { CLHS, CRHS };
1532 return ConstantFoldInstOperands(Instruction::Or, CLHS->getType(),
1536 // Canonicalize the constant to the RHS.
1537 std::swap(Op0, Op1);
1541 if (match(Op1, m_Undef()))
1542 return Constant::getAllOnesValue(Op0->getType());
1549 if (match(Op1, m_Zero()))
1553 if (match(Op1, m_AllOnes()))
1556 // A | ~A = ~A | A = -1
1557 if (match(Op0, m_Not(m_Specific(Op1))) ||
1558 match(Op1, m_Not(m_Specific(Op0))))
1559 return Constant::getAllOnesValue(Op0->getType());
1562 Value *A = 0, *B = 0;
1563 if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
1564 (A == Op1 || B == Op1))
1568 if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
1569 (A == Op0 || B == Op0))
1572 // ~(A & ?) | A = -1
1573 if (match(Op0, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1574 (A == Op1 || B == Op1))
1575 return Constant::getAllOnesValue(Op1->getType());
1577 // A | ~(A & ?) = -1
1578 if (match(Op1, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1579 (A == Op0 || B == Op0))
1580 return Constant::getAllOnesValue(Op0->getType());
1582 // Try some generic simplifications for associative operations.
1583 if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
1587 // Or distributes over And. Try some generic simplifications based on this.
1588 if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
1592 // And distributes over Or. Try some generic simplifications based on this.
1593 if (Value *V = FactorizeBinOp(Instruction::Or, Op0, Op1, Instruction::And,
1597 // If the operation is with the result of a select instruction, check whether
1598 // operating on either branch of the select always yields the same value.
1599 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1600 if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
1604 // If the operation is with the result of a phi instruction, check whether
1605 // operating on all incoming values of the phi always yields the same value.
1606 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1607 if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
1613 Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const DataLayout *TD,
1614 const TargetLibraryInfo *TLI,
1615 const DominatorTree *DT) {
1616 return ::SimplifyOrInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1619 /// SimplifyXorInst - Given operands for a Xor, see if we can
1620 /// fold the result. If not, this returns null.
1621 static Value *SimplifyXorInst(Value *Op0, Value *Op1, const Query &Q,
1622 unsigned MaxRecurse) {
1623 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1624 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1625 Constant *Ops[] = { CLHS, CRHS };
1626 return ConstantFoldInstOperands(Instruction::Xor, CLHS->getType(),
1630 // Canonicalize the constant to the RHS.
1631 std::swap(Op0, Op1);
1634 // A ^ undef -> undef
1635 if (match(Op1, m_Undef()))
1639 if (match(Op1, m_Zero()))
1644 return Constant::getNullValue(Op0->getType());
1646 // A ^ ~A = ~A ^ A = -1
1647 if (match(Op0, m_Not(m_Specific(Op1))) ||
1648 match(Op1, m_Not(m_Specific(Op0))))
1649 return Constant::getAllOnesValue(Op0->getType());
1651 // Try some generic simplifications for associative operations.
1652 if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
1656 // And distributes over Xor. Try some generic simplifications based on this.
1657 if (Value *V = FactorizeBinOp(Instruction::Xor, Op0, Op1, Instruction::And,
1661 // Threading Xor over selects and phi nodes is pointless, so don't bother.
1662 // Threading over the select in "A ^ select(cond, B, C)" means evaluating
1663 // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
1664 // only if B and C are equal. If B and C are equal then (since we assume
1665 // that operands have already been simplified) "select(cond, B, C)" should
1666 // have been simplified to the common value of B and C already. Analysing
1667 // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
1668 // for threading over phi nodes.
1673 Value *llvm::SimplifyXorInst(Value *Op0, Value *Op1, const DataLayout *TD,
1674 const TargetLibraryInfo *TLI,
1675 const DominatorTree *DT) {
1676 return ::SimplifyXorInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1679 static Type *GetCompareTy(Value *Op) {
1680 return CmpInst::makeCmpResultType(Op->getType());
1683 /// ExtractEquivalentCondition - Rummage around inside V looking for something
1684 /// equivalent to the comparison "LHS Pred RHS". Return such a value if found,
1685 /// otherwise return null. Helper function for analyzing max/min idioms.
1686 static Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred,
1687 Value *LHS, Value *RHS) {
1688 SelectInst *SI = dyn_cast<SelectInst>(V);
1691 CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
1694 Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
1695 if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
1697 if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
1698 LHS == CmpRHS && RHS == CmpLHS)
1703 // A significant optimization not implemented here is assuming that alloca
1704 // addresses are not equal to incoming argument values. They don't *alias*,
1705 // as we say, but that doesn't mean they aren't equal, so we take a
1706 // conservative approach.
1708 // This is inspired in part by C++11 5.10p1:
1709 // "Two pointers of the same type compare equal if and only if they are both
1710 // null, both point to the same function, or both represent the same
1713 // This is pretty permissive.
1715 // It's also partly due to C11 6.5.9p6:
1716 // "Two pointers compare equal if and only if both are null pointers, both are
1717 // pointers to the same object (including a pointer to an object and a
1718 // subobject at its beginning) or function, both are pointers to one past the
1719 // last element of the same array object, or one is a pointer to one past the
1720 // end of one array object and the other is a pointer to the start of a
1721 // different array object that happens to immediately follow the first array
1722 // object in the address space.)
1724 // C11's version is more restrictive, however there's no reason why an argument
1725 // couldn't be a one-past-the-end value for a stack object in the caller and be
1726 // equal to the beginning of a stack object in the callee.
1728 // If the C and C++ standards are ever made sufficiently restrictive in this
1729 // area, it may be possible to update LLVM's semantics accordingly and reinstate
1730 // this optimization.
1731 static Constant *computePointerICmp(const DataLayout *TD,
1732 const TargetLibraryInfo *TLI,
1733 CmpInst::Predicate Pred,
1734 Value *LHS, Value *RHS) {
1735 // First, skip past any trivial no-ops.
1736 LHS = LHS->stripPointerCasts();
1737 RHS = RHS->stripPointerCasts();
1739 // A non-null pointer is not equal to a null pointer.
1740 if (llvm::isKnownNonNull(LHS) && isa<ConstantPointerNull>(RHS) &&
1741 (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE))
1742 return ConstantInt::get(GetCompareTy(LHS),
1743 !CmpInst::isTrueWhenEqual(Pred));
1745 // We can only fold certain predicates on pointer comparisons.
1750 // Equality comaprisons are easy to fold.
1751 case CmpInst::ICMP_EQ:
1752 case CmpInst::ICMP_NE:
1755 // We can only handle unsigned relational comparisons because 'inbounds' on
1756 // a GEP only protects against unsigned wrapping.
1757 case CmpInst::ICMP_UGT:
1758 case CmpInst::ICMP_UGE:
1759 case CmpInst::ICMP_ULT:
1760 case CmpInst::ICMP_ULE:
1761 // However, we have to switch them to their signed variants to handle
1762 // negative indices from the base pointer.
1763 Pred = ICmpInst::getSignedPredicate(Pred);
1767 // Strip off any constant offsets so that we can reason about them.
1768 // It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets
1769 // here and compare base addresses like AliasAnalysis does, however there are
1770 // numerous hazards. AliasAnalysis and its utilities rely on special rules
1771 // governing loads and stores which don't apply to icmps. Also, AliasAnalysis
1772 // doesn't need to guarantee pointer inequality when it says NoAlias.
1773 Constant *LHSOffset = stripAndComputeConstantOffsets(TD, LHS);
1774 Constant *RHSOffset = stripAndComputeConstantOffsets(TD, RHS);
1776 // If LHS and RHS are related via constant offsets to the same base
1777 // value, we can replace it with an icmp which just compares the offsets.
1779 return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset);
1781 // Various optimizations for (in)equality comparisons.
1782 if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE) {
1783 // Different non-empty allocations that exist at the same time have
1784 // different addresses (if the program can tell). Global variables always
1785 // exist, so they always exist during the lifetime of each other and all
1786 // allocas. Two different allocas usually have different addresses...
1788 // However, if there's an @llvm.stackrestore dynamically in between two
1789 // allocas, they may have the same address. It's tempting to reduce the
1790 // scope of the problem by only looking at *static* allocas here. That would
1791 // cover the majority of allocas while significantly reducing the likelihood
1792 // of having an @llvm.stackrestore pop up in the middle. However, it's not
1793 // actually impossible for an @llvm.stackrestore to pop up in the middle of
1794 // an entry block. Also, if we have a block that's not attached to a
1795 // function, we can't tell if it's "static" under the current definition.
1796 // Theoretically, this problem could be fixed by creating a new kind of
1797 // instruction kind specifically for static allocas. Such a new instruction
1798 // could be required to be at the top of the entry block, thus preventing it
1799 // from being subject to a @llvm.stackrestore. Instcombine could even
1800 // convert regular allocas into these special allocas. It'd be nifty.
1801 // However, until then, this problem remains open.
1803 // So, we'll assume that two non-empty allocas have different addresses
1806 // With all that, if the offsets are within the bounds of their allocations
1807 // (and not one-past-the-end! so we can't use inbounds!), and their
1808 // allocations aren't the same, the pointers are not equal.
1810 // Note that it's not necessary to check for LHS being a global variable
1811 // address, due to canonicalization and constant folding.
1812 if (isa<AllocaInst>(LHS) &&
1813 (isa<AllocaInst>(RHS) || isa<GlobalVariable>(RHS))) {
1814 ConstantInt *LHSOffsetCI = dyn_cast<ConstantInt>(LHSOffset);
1815 ConstantInt *RHSOffsetCI = dyn_cast<ConstantInt>(RHSOffset);
1816 uint64_t LHSSize, RHSSize;
1817 if (LHSOffsetCI && RHSOffsetCI &&
1818 getObjectSize(LHS, LHSSize, TD, TLI) &&
1819 getObjectSize(RHS, RHSSize, TD, TLI)) {
1820 const APInt &LHSOffsetValue = LHSOffsetCI->getValue();
1821 const APInt &RHSOffsetValue = RHSOffsetCI->getValue();
1822 if (!LHSOffsetValue.isNegative() &&
1823 !RHSOffsetValue.isNegative() &&
1824 LHSOffsetValue.ult(LHSSize) &&
1825 RHSOffsetValue.ult(RHSSize)) {
1826 return ConstantInt::get(GetCompareTy(LHS),
1827 !CmpInst::isTrueWhenEqual(Pred));
1831 // Repeat the above check but this time without depending on DataLayout
1832 // or being able to compute a precise size.
1833 if (!cast<PointerType>(LHS->getType())->isEmptyTy() &&
1834 !cast<PointerType>(RHS->getType())->isEmptyTy() &&
1835 LHSOffset->isNullValue() &&
1836 RHSOffset->isNullValue())
1837 return ConstantInt::get(GetCompareTy(LHS),
1838 !CmpInst::isTrueWhenEqual(Pred));
1846 /// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
1847 /// fold the result. If not, this returns null.
1848 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
1849 const Query &Q, unsigned MaxRecurse) {
1850 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
1851 assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
1853 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
1854 if (Constant *CRHS = dyn_cast<Constant>(RHS))
1855 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.TD, Q.TLI);
1857 // If we have a constant, make sure it is on the RHS.
1858 std::swap(LHS, RHS);
1859 Pred = CmpInst::getSwappedPredicate(Pred);
1862 Type *ITy = GetCompareTy(LHS); // The return type.
1863 Type *OpTy = LHS->getType(); // The operand type.
1865 // icmp X, X -> true/false
1866 // X icmp undef -> true/false. For example, icmp ugt %X, undef -> false
1867 // because X could be 0.
1868 if (LHS == RHS || isa<UndefValue>(RHS))
1869 return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
1871 // Special case logic when the operands have i1 type.
1872 if (OpTy->getScalarType()->isIntegerTy(1)) {
1875 case ICmpInst::ICMP_EQ:
1877 if (match(RHS, m_One()))
1880 case ICmpInst::ICMP_NE:
1882 if (match(RHS, m_Zero()))
1885 case ICmpInst::ICMP_UGT:
1887 if (match(RHS, m_Zero()))
1890 case ICmpInst::ICMP_UGE:
1892 if (match(RHS, m_One()))
1895 case ICmpInst::ICMP_SLT:
1897 if (match(RHS, m_Zero()))
1900 case ICmpInst::ICMP_SLE:
1902 if (match(RHS, m_One()))
1908 // If we are comparing with zero then try hard since this is a common case.
1909 if (match(RHS, m_Zero())) {
1910 bool LHSKnownNonNegative, LHSKnownNegative;
1912 default: llvm_unreachable("Unknown ICmp predicate!");
1913 case ICmpInst::ICMP_ULT:
1914 return getFalse(ITy);
1915 case ICmpInst::ICMP_UGE:
1916 return getTrue(ITy);
1917 case ICmpInst::ICMP_EQ:
1918 case ICmpInst::ICMP_ULE:
1919 if (isKnownNonZero(LHS, Q.TD))
1920 return getFalse(ITy);
1922 case ICmpInst::ICMP_NE:
1923 case ICmpInst::ICMP_UGT:
1924 if (isKnownNonZero(LHS, Q.TD))
1925 return getTrue(ITy);
1927 case ICmpInst::ICMP_SLT:
1928 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1929 if (LHSKnownNegative)
1930 return getTrue(ITy);
1931 if (LHSKnownNonNegative)
1932 return getFalse(ITy);
1934 case ICmpInst::ICMP_SLE:
1935 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1936 if (LHSKnownNegative)
1937 return getTrue(ITy);
1938 if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.TD))
1939 return getFalse(ITy);
1941 case ICmpInst::ICMP_SGE:
1942 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1943 if (LHSKnownNegative)
1944 return getFalse(ITy);
1945 if (LHSKnownNonNegative)
1946 return getTrue(ITy);
1948 case ICmpInst::ICMP_SGT:
1949 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1950 if (LHSKnownNegative)
1951 return getFalse(ITy);
1952 if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.TD))
1953 return getTrue(ITy);
1958 // See if we are doing a comparison with a constant integer.
1959 if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
1960 // Rule out tautological comparisons (eg., ult 0 or uge 0).
1961 ConstantRange RHS_CR = ICmpInst::makeConstantRange(Pred, CI->getValue());
1962 if (RHS_CR.isEmptySet())
1963 return ConstantInt::getFalse(CI->getContext());
1964 if (RHS_CR.isFullSet())
1965 return ConstantInt::getTrue(CI->getContext());
1967 // Many binary operators with constant RHS have easy to compute constant
1968 // range. Use them to check whether the comparison is a tautology.
1969 uint32_t Width = CI->getBitWidth();
1970 APInt Lower = APInt(Width, 0);
1971 APInt Upper = APInt(Width, 0);
1973 if (match(LHS, m_URem(m_Value(), m_ConstantInt(CI2)))) {
1974 // 'urem x, CI2' produces [0, CI2).
1975 Upper = CI2->getValue();
1976 } else if (match(LHS, m_SRem(m_Value(), m_ConstantInt(CI2)))) {
1977 // 'srem x, CI2' produces (-|CI2|, |CI2|).
1978 Upper = CI2->getValue().abs();
1979 Lower = (-Upper) + 1;
1980 } else if (match(LHS, m_UDiv(m_ConstantInt(CI2), m_Value()))) {
1981 // 'udiv CI2, x' produces [0, CI2].
1982 Upper = CI2->getValue() + 1;
1983 } else if (match(LHS, m_UDiv(m_Value(), m_ConstantInt(CI2)))) {
1984 // 'udiv x, CI2' produces [0, UINT_MAX / CI2].
1985 APInt NegOne = APInt::getAllOnesValue(Width);
1987 Upper = NegOne.udiv(CI2->getValue()) + 1;
1988 } else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) {
1989 // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2].
1990 APInt IntMin = APInt::getSignedMinValue(Width);
1991 APInt IntMax = APInt::getSignedMaxValue(Width);
1992 APInt Val = CI2->getValue().abs();
1993 if (!Val.isMinValue()) {
1994 Lower = IntMin.sdiv(Val);
1995 Upper = IntMax.sdiv(Val) + 1;
1997 } else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) {
1998 // 'lshr x, CI2' produces [0, UINT_MAX >> CI2].
1999 APInt NegOne = APInt::getAllOnesValue(Width);
2000 if (CI2->getValue().ult(Width))
2001 Upper = NegOne.lshr(CI2->getValue()) + 1;
2002 } else if (match(LHS, m_AShr(m_Value(), m_ConstantInt(CI2)))) {
2003 // 'ashr x, CI2' produces [INT_MIN >> CI2, INT_MAX >> CI2].
2004 APInt IntMin = APInt::getSignedMinValue(Width);
2005 APInt IntMax = APInt::getSignedMaxValue(Width);
2006 if (CI2->getValue().ult(Width)) {
2007 Lower = IntMin.ashr(CI2->getValue());
2008 Upper = IntMax.ashr(CI2->getValue()) + 1;
2010 } else if (match(LHS, m_Or(m_Value(), m_ConstantInt(CI2)))) {
2011 // 'or x, CI2' produces [CI2, UINT_MAX].
2012 Lower = CI2->getValue();
2013 } else if (match(LHS, m_And(m_Value(), m_ConstantInt(CI2)))) {
2014 // 'and x, CI2' produces [0, CI2].
2015 Upper = CI2->getValue() + 1;
2017 if (Lower != Upper) {
2018 ConstantRange LHS_CR = ConstantRange(Lower, Upper);
2019 if (RHS_CR.contains(LHS_CR))
2020 return ConstantInt::getTrue(RHS->getContext());
2021 if (RHS_CR.inverse().contains(LHS_CR))
2022 return ConstantInt::getFalse(RHS->getContext());
2026 // Compare of cast, for example (zext X) != 0 -> X != 0
2027 if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
2028 Instruction *LI = cast<CastInst>(LHS);
2029 Value *SrcOp = LI->getOperand(0);
2030 Type *SrcTy = SrcOp->getType();
2031 Type *DstTy = LI->getType();
2033 // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
2034 // if the integer type is the same size as the pointer type.
2035 if (MaxRecurse && Q.TD && isa<PtrToIntInst>(LI) &&
2036 Q.TD->getTypeSizeInBits(SrcTy) == DstTy->getPrimitiveSizeInBits()) {
2037 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
2038 // Transfer the cast to the constant.
2039 if (Value *V = SimplifyICmpInst(Pred, SrcOp,
2040 ConstantExpr::getIntToPtr(RHSC, SrcTy),
2043 } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
2044 if (RI->getOperand(0)->getType() == SrcTy)
2045 // Compare without the cast.
2046 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2052 if (isa<ZExtInst>(LHS)) {
2053 // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
2055 if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
2056 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2057 // Compare X and Y. Note that signed predicates become unsigned.
2058 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
2059 SrcOp, RI->getOperand(0), Q,
2063 // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
2064 // too. If not, then try to deduce the result of the comparison.
2065 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2066 // Compute the constant that would happen if we truncated to SrcTy then
2067 // reextended to DstTy.
2068 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2069 Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
2071 // If the re-extended constant didn't change then this is effectively
2072 // also a case of comparing two zero-extended values.
2073 if (RExt == CI && MaxRecurse)
2074 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
2075 SrcOp, Trunc, Q, MaxRecurse-1))
2078 // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
2079 // there. Use this to work out the result of the comparison.
2082 default: llvm_unreachable("Unknown ICmp predicate!");
2084 case ICmpInst::ICMP_EQ:
2085 case ICmpInst::ICMP_UGT:
2086 case ICmpInst::ICMP_UGE:
2087 return ConstantInt::getFalse(CI->getContext());
2089 case ICmpInst::ICMP_NE:
2090 case ICmpInst::ICMP_ULT:
2091 case ICmpInst::ICMP_ULE:
2092 return ConstantInt::getTrue(CI->getContext());
2094 // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
2095 // is non-negative then LHS <s RHS.
2096 case ICmpInst::ICMP_SGT:
2097 case ICmpInst::ICMP_SGE:
2098 return CI->getValue().isNegative() ?
2099 ConstantInt::getTrue(CI->getContext()) :
2100 ConstantInt::getFalse(CI->getContext());
2102 case ICmpInst::ICMP_SLT:
2103 case ICmpInst::ICMP_SLE:
2104 return CI->getValue().isNegative() ?
2105 ConstantInt::getFalse(CI->getContext()) :
2106 ConstantInt::getTrue(CI->getContext());
2112 if (isa<SExtInst>(LHS)) {
2113 // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
2115 if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
2116 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2117 // Compare X and Y. Note that the predicate does not change.
2118 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2122 // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
2123 // too. If not, then try to deduce the result of the comparison.
2124 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2125 // Compute the constant that would happen if we truncated to SrcTy then
2126 // reextended to DstTy.
2127 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2128 Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
2130 // If the re-extended constant didn't change then this is effectively
2131 // also a case of comparing two sign-extended values.
2132 if (RExt == CI && MaxRecurse)
2133 if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
2136 // Otherwise the upper bits of LHS are all equal, while RHS has varying
2137 // bits there. Use this to work out the result of the comparison.
2140 default: llvm_unreachable("Unknown ICmp predicate!");
2141 case ICmpInst::ICMP_EQ:
2142 return ConstantInt::getFalse(CI->getContext());
2143 case ICmpInst::ICMP_NE:
2144 return ConstantInt::getTrue(CI->getContext());
2146 // If RHS is non-negative then LHS <s RHS. If RHS is negative then
2148 case ICmpInst::ICMP_SGT:
2149 case ICmpInst::ICMP_SGE:
2150 return CI->getValue().isNegative() ?
2151 ConstantInt::getTrue(CI->getContext()) :
2152 ConstantInt::getFalse(CI->getContext());
2153 case ICmpInst::ICMP_SLT:
2154 case ICmpInst::ICMP_SLE:
2155 return CI->getValue().isNegative() ?
2156 ConstantInt::getFalse(CI->getContext()) :
2157 ConstantInt::getTrue(CI->getContext());
2159 // If LHS is non-negative then LHS <u RHS. If LHS is negative then
2161 case ICmpInst::ICMP_UGT:
2162 case ICmpInst::ICMP_UGE:
2163 // Comparison is true iff the LHS <s 0.
2165 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
2166 Constant::getNullValue(SrcTy),
2170 case ICmpInst::ICMP_ULT:
2171 case ICmpInst::ICMP_ULE:
2172 // Comparison is true iff the LHS >=s 0.
2174 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
2175 Constant::getNullValue(SrcTy),
2185 // Special logic for binary operators.
2186 BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
2187 BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
2188 if (MaxRecurse && (LBO || RBO)) {
2189 // Analyze the case when either LHS or RHS is an add instruction.
2190 Value *A = 0, *B = 0, *C = 0, *D = 0;
2191 // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
2192 bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
2193 if (LBO && LBO->getOpcode() == Instruction::Add) {
2194 A = LBO->getOperand(0); B = LBO->getOperand(1);
2195 NoLHSWrapProblem = ICmpInst::isEquality(Pred) ||
2196 (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
2197 (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
2199 if (RBO && RBO->getOpcode() == Instruction::Add) {
2200 C = RBO->getOperand(0); D = RBO->getOperand(1);
2201 NoRHSWrapProblem = ICmpInst::isEquality(Pred) ||
2202 (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
2203 (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
2206 // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
2207 if ((A == RHS || B == RHS) && NoLHSWrapProblem)
2208 if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
2209 Constant::getNullValue(RHS->getType()),
2213 // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
2214 if ((C == LHS || D == LHS) && NoRHSWrapProblem)
2215 if (Value *V = SimplifyICmpInst(Pred,
2216 Constant::getNullValue(LHS->getType()),
2217 C == LHS ? D : C, Q, MaxRecurse-1))
2220 // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
2221 if (A && C && (A == C || A == D || B == C || B == D) &&
2222 NoLHSWrapProblem && NoRHSWrapProblem) {
2223 // Determine Y and Z in the form icmp (X+Y), (X+Z).
2226 // C + B == C + D -> B == D
2229 } else if (A == D) {
2230 // D + B == C + D -> B == C
2233 } else if (B == C) {
2234 // A + C == C + D -> A == D
2239 // A + D == C + D -> A == C
2243 if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse-1))
2248 // icmp pred (urem X, Y), Y
2249 if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
2250 bool KnownNonNegative, KnownNegative;
2254 case ICmpInst::ICMP_SGT:
2255 case ICmpInst::ICMP_SGE:
2256 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.TD);
2257 if (!KnownNonNegative)
2260 case ICmpInst::ICMP_EQ:
2261 case ICmpInst::ICMP_UGT:
2262 case ICmpInst::ICMP_UGE:
2263 return getFalse(ITy);
2264 case ICmpInst::ICMP_SLT:
2265 case ICmpInst::ICMP_SLE:
2266 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.TD);
2267 if (!KnownNonNegative)
2270 case ICmpInst::ICMP_NE:
2271 case ICmpInst::ICMP_ULT:
2272 case ICmpInst::ICMP_ULE:
2273 return getTrue(ITy);
2277 // icmp pred X, (urem Y, X)
2278 if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
2279 bool KnownNonNegative, KnownNegative;
2283 case ICmpInst::ICMP_SGT:
2284 case ICmpInst::ICMP_SGE:
2285 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.TD);
2286 if (!KnownNonNegative)
2289 case ICmpInst::ICMP_NE:
2290 case ICmpInst::ICMP_UGT:
2291 case ICmpInst::ICMP_UGE:
2292 return getTrue(ITy);
2293 case ICmpInst::ICMP_SLT:
2294 case ICmpInst::ICMP_SLE:
2295 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.TD);
2296 if (!KnownNonNegative)
2299 case ICmpInst::ICMP_EQ:
2300 case ICmpInst::ICMP_ULT:
2301 case ICmpInst::ICMP_ULE:
2302 return getFalse(ITy);
2307 if (LBO && match(LBO, m_UDiv(m_Specific(RHS), m_Value()))) {
2308 // icmp pred (X /u Y), X
2309 if (Pred == ICmpInst::ICMP_UGT)
2310 return getFalse(ITy);
2311 if (Pred == ICmpInst::ICMP_ULE)
2312 return getTrue(ITy);
2315 if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
2316 LBO->getOperand(1) == RBO->getOperand(1)) {
2317 switch (LBO->getOpcode()) {
2319 case Instruction::UDiv:
2320 case Instruction::LShr:
2321 if (ICmpInst::isSigned(Pred))
2324 case Instruction::SDiv:
2325 case Instruction::AShr:
2326 if (!LBO->isExact() || !RBO->isExact())
2328 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2329 RBO->getOperand(0), Q, MaxRecurse-1))
2332 case Instruction::Shl: {
2333 bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
2334 bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
2337 if (!NSW && ICmpInst::isSigned(Pred))
2339 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2340 RBO->getOperand(0), Q, MaxRecurse-1))
2347 // Simplify comparisons involving max/min.
2349 CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE;
2350 CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
2352 // Signed variants on "max(a,b)>=a -> true".
2353 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2354 if (A != RHS) std::swap(A, B); // smax(A, B) pred A.
2355 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2356 // We analyze this as smax(A, B) pred A.
2358 } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
2359 (A == LHS || B == LHS)) {
2360 if (A != LHS) std::swap(A, B); // A pred smax(A, B).
2361 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2362 // We analyze this as smax(A, B) swapped-pred A.
2363 P = CmpInst::getSwappedPredicate(Pred);
2364 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2365 (A == RHS || B == RHS)) {
2366 if (A != RHS) std::swap(A, B); // smin(A, B) pred A.
2367 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2368 // We analyze this as smax(-A, -B) swapped-pred -A.
2369 // Note that we do not need to actually form -A or -B thanks to EqP.
2370 P = CmpInst::getSwappedPredicate(Pred);
2371 } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
2372 (A == LHS || B == LHS)) {
2373 if (A != LHS) std::swap(A, B); // A pred smin(A, B).
2374 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2375 // We analyze this as smax(-A, -B) pred -A.
2376 // Note that we do not need to actually form -A or -B thanks to EqP.
2379 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2380 // Cases correspond to "max(A, B) p A".
2384 case CmpInst::ICMP_EQ:
2385 case CmpInst::ICMP_SLE:
2386 // Equivalent to "A EqP B". This may be the same as the condition tested
2387 // in the max/min; if so, we can just return that.
2388 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2390 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2392 // Otherwise, see if "A EqP B" simplifies.
2394 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2397 case CmpInst::ICMP_NE:
2398 case CmpInst::ICMP_SGT: {
2399 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2400 // Equivalent to "A InvEqP B". This may be the same as the condition
2401 // tested in the max/min; if so, we can just return that.
2402 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2404 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2406 // Otherwise, see if "A InvEqP B" simplifies.
2408 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2412 case CmpInst::ICMP_SGE:
2414 return getTrue(ITy);
2415 case CmpInst::ICMP_SLT:
2417 return getFalse(ITy);
2421 // Unsigned variants on "max(a,b)>=a -> true".
2422 P = CmpInst::BAD_ICMP_PREDICATE;
2423 if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2424 if (A != RHS) std::swap(A, B); // umax(A, B) pred A.
2425 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2426 // We analyze this as umax(A, B) pred A.
2428 } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
2429 (A == LHS || B == LHS)) {
2430 if (A != LHS) std::swap(A, B); // A pred umax(A, B).
2431 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2432 // We analyze this as umax(A, B) swapped-pred A.
2433 P = CmpInst::getSwappedPredicate(Pred);
2434 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2435 (A == RHS || B == RHS)) {
2436 if (A != RHS) std::swap(A, B); // umin(A, B) pred A.
2437 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2438 // We analyze this as umax(-A, -B) swapped-pred -A.
2439 // Note that we do not need to actually form -A or -B thanks to EqP.
2440 P = CmpInst::getSwappedPredicate(Pred);
2441 } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
2442 (A == LHS || B == LHS)) {
2443 if (A != LHS) std::swap(A, B); // A pred umin(A, B).
2444 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2445 // We analyze this as umax(-A, -B) pred -A.
2446 // Note that we do not need to actually form -A or -B thanks to EqP.
2449 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2450 // Cases correspond to "max(A, B) p A".
2454 case CmpInst::ICMP_EQ:
2455 case CmpInst::ICMP_ULE:
2456 // Equivalent to "A EqP B". This may be the same as the condition tested
2457 // in the max/min; if so, we can just return that.
2458 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2460 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2462 // Otherwise, see if "A EqP B" simplifies.
2464 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2467 case CmpInst::ICMP_NE:
2468 case CmpInst::ICMP_UGT: {
2469 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2470 // Equivalent to "A InvEqP B". This may be the same as the condition
2471 // tested in the max/min; if so, we can just return that.
2472 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2474 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2476 // Otherwise, see if "A InvEqP B" simplifies.
2478 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2482 case CmpInst::ICMP_UGE:
2484 return getTrue(ITy);
2485 case CmpInst::ICMP_ULT:
2487 return getFalse(ITy);
2491 // Variants on "max(x,y) >= min(x,z)".
2493 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
2494 match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
2495 (A == C || A == D || B == C || B == D)) {
2496 // max(x, ?) pred min(x, ?).
2497 if (Pred == CmpInst::ICMP_SGE)
2499 return getTrue(ITy);
2500 if (Pred == CmpInst::ICMP_SLT)
2502 return getFalse(ITy);
2503 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2504 match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
2505 (A == C || A == D || B == C || B == D)) {
2506 // min(x, ?) pred max(x, ?).
2507 if (Pred == CmpInst::ICMP_SLE)
2509 return getTrue(ITy);
2510 if (Pred == CmpInst::ICMP_SGT)
2512 return getFalse(ITy);
2513 } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
2514 match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
2515 (A == C || A == D || B == C || B == D)) {
2516 // max(x, ?) pred min(x, ?).
2517 if (Pred == CmpInst::ICMP_UGE)
2519 return getTrue(ITy);
2520 if (Pred == CmpInst::ICMP_ULT)
2522 return getFalse(ITy);
2523 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2524 match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
2525 (A == C || A == D || B == C || B == D)) {
2526 // min(x, ?) pred max(x, ?).
2527 if (Pred == CmpInst::ICMP_ULE)
2529 return getTrue(ITy);
2530 if (Pred == CmpInst::ICMP_UGT)
2532 return getFalse(ITy);
2535 // Simplify comparisons of related pointers using a powerful, recursive
2536 // GEP-walk when we have target data available..
2537 if (LHS->getType()->isPointerTy())
2538 if (Constant *C = computePointerICmp(Q.TD, Q.TLI, Pred, LHS, RHS))
2541 if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
2542 if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
2543 if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
2544 GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
2545 (ICmpInst::isEquality(Pred) ||
2546 (GLHS->isInBounds() && GRHS->isInBounds() &&
2547 Pred == ICmpInst::getSignedPredicate(Pred)))) {
2548 // The bases are equal and the indices are constant. Build a constant
2549 // expression GEP with the same indices and a null base pointer to see
2550 // what constant folding can make out of it.
2551 Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
2552 SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
2553 Constant *NewLHS = ConstantExpr::getGetElementPtr(Null, IndicesLHS);
2555 SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
2556 Constant *NewRHS = ConstantExpr::getGetElementPtr(Null, IndicesRHS);
2557 return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
2562 // If the comparison is with the result of a select instruction, check whether
2563 // comparing with either branch of the select always yields the same value.
2564 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2565 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
2568 // If the comparison is with the result of a phi instruction, check whether
2569 // doing the compare with each incoming phi value yields a common result.
2570 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2571 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
2577 Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2578 const DataLayout *TD,
2579 const TargetLibraryInfo *TLI,
2580 const DominatorTree *DT) {
2581 return ::SimplifyICmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
2585 /// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can
2586 /// fold the result. If not, this returns null.
2587 static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2588 const Query &Q, unsigned MaxRecurse) {
2589 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
2590 assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
2592 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
2593 if (Constant *CRHS = dyn_cast<Constant>(RHS))
2594 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.TD, Q.TLI);
2596 // If we have a constant, make sure it is on the RHS.
2597 std::swap(LHS, RHS);
2598 Pred = CmpInst::getSwappedPredicate(Pred);
2601 // Fold trivial predicates.
2602 if (Pred == FCmpInst::FCMP_FALSE)
2603 return ConstantInt::get(GetCompareTy(LHS), 0);
2604 if (Pred == FCmpInst::FCMP_TRUE)
2605 return ConstantInt::get(GetCompareTy(LHS), 1);
2607 if (isa<UndefValue>(RHS)) // fcmp pred X, undef -> undef
2608 return UndefValue::get(GetCompareTy(LHS));
2610 // fcmp x,x -> true/false. Not all compares are foldable.
2612 if (CmpInst::isTrueWhenEqual(Pred))
2613 return ConstantInt::get(GetCompareTy(LHS), 1);
2614 if (CmpInst::isFalseWhenEqual(Pred))
2615 return ConstantInt::get(GetCompareTy(LHS), 0);
2618 // Handle fcmp with constant RHS
2619 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
2620 // If the constant is a nan, see if we can fold the comparison based on it.
2621 if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHSC)) {
2622 if (CFP->getValueAPF().isNaN()) {
2623 if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo"
2624 return ConstantInt::getFalse(CFP->getContext());
2625 assert(FCmpInst::isUnordered(Pred) &&
2626 "Comparison must be either ordered or unordered!");
2627 // True if unordered.
2628 return ConstantInt::getTrue(CFP->getContext());
2630 // Check whether the constant is an infinity.
2631 if (CFP->getValueAPF().isInfinity()) {
2632 if (CFP->getValueAPF().isNegative()) {
2634 case FCmpInst::FCMP_OLT:
2635 // No value is ordered and less than negative infinity.
2636 return ConstantInt::getFalse(CFP->getContext());
2637 case FCmpInst::FCMP_UGE:
2638 // All values are unordered with or at least negative infinity.
2639 return ConstantInt::getTrue(CFP->getContext());
2645 case FCmpInst::FCMP_OGT:
2646 // No value is ordered and greater than infinity.
2647 return ConstantInt::getFalse(CFP->getContext());
2648 case FCmpInst::FCMP_ULE:
2649 // All values are unordered with and at most infinity.
2650 return ConstantInt::getTrue(CFP->getContext());
2659 // If the comparison is with the result of a select instruction, check whether
2660 // comparing with either branch of the select always yields the same value.
2661 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2662 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
2665 // If the comparison is with the result of a phi instruction, check whether
2666 // doing the compare with each incoming phi value yields a common result.
2667 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2668 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
2674 Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2675 const DataLayout *TD,
2676 const TargetLibraryInfo *TLI,
2677 const DominatorTree *DT) {
2678 return ::SimplifyFCmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
2682 /// SimplifySelectInst - Given operands for a SelectInst, see if we can fold
2683 /// the result. If not, this returns null.
2684 static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal,
2685 Value *FalseVal, const Query &Q,
2686 unsigned MaxRecurse) {
2687 // select true, X, Y -> X
2688 // select false, X, Y -> Y
2689 if (ConstantInt *CB = dyn_cast<ConstantInt>(CondVal))
2690 return CB->getZExtValue() ? TrueVal : FalseVal;
2692 // select C, X, X -> X
2693 if (TrueVal == FalseVal)
2696 if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y
2697 if (isa<Constant>(TrueVal))
2701 if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X
2703 if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
2709 Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
2710 const DataLayout *TD,
2711 const TargetLibraryInfo *TLI,
2712 const DominatorTree *DT) {
2713 return ::SimplifySelectInst(Cond, TrueVal, FalseVal, Query (TD, TLI, DT),
2717 /// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
2718 /// fold the result. If not, this returns null.
2719 static Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const Query &Q, unsigned) {
2720 // The type of the GEP pointer operand.
2721 PointerType *PtrTy = dyn_cast<PointerType>(Ops[0]->getType());
2722 // The GEP pointer operand is not a pointer, it's a vector of pointers.
2726 // getelementptr P -> P.
2727 if (Ops.size() == 1)
2730 if (isa<UndefValue>(Ops[0])) {
2731 // Compute the (pointer) type returned by the GEP instruction.
2732 Type *LastType = GetElementPtrInst::getIndexedType(PtrTy, Ops.slice(1));
2733 Type *GEPTy = PointerType::get(LastType, PtrTy->getAddressSpace());
2734 return UndefValue::get(GEPTy);
2737 if (Ops.size() == 2) {
2738 // getelementptr P, 0 -> P.
2739 if (ConstantInt *C = dyn_cast<ConstantInt>(Ops[1]))
2742 // getelementptr P, N -> P if P points to a type of zero size.
2744 Type *Ty = PtrTy->getElementType();
2745 if (Ty->isSized() && Q.TD->getTypeAllocSize(Ty) == 0)
2750 // Check to see if this is constant foldable.
2751 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
2752 if (!isa<Constant>(Ops[i]))
2755 return ConstantExpr::getGetElementPtr(cast<Constant>(Ops[0]), Ops.slice(1));
2758 Value *llvm::SimplifyGEPInst(ArrayRef<Value *> Ops, const DataLayout *TD,
2759 const TargetLibraryInfo *TLI,
2760 const DominatorTree *DT) {
2761 return ::SimplifyGEPInst(Ops, Query (TD, TLI, DT), RecursionLimit);
2764 /// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we
2765 /// can fold the result. If not, this returns null.
2766 static Value *SimplifyInsertValueInst(Value *Agg, Value *Val,
2767 ArrayRef<unsigned> Idxs, const Query &Q,
2769 if (Constant *CAgg = dyn_cast<Constant>(Agg))
2770 if (Constant *CVal = dyn_cast<Constant>(Val))
2771 return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
2773 // insertvalue x, undef, n -> x
2774 if (match(Val, m_Undef()))
2777 // insertvalue x, (extractvalue y, n), n
2778 if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
2779 if (EV->getAggregateOperand()->getType() == Agg->getType() &&
2780 EV->getIndices() == Idxs) {
2781 // insertvalue undef, (extractvalue y, n), n -> y
2782 if (match(Agg, m_Undef()))
2783 return EV->getAggregateOperand();
2785 // insertvalue y, (extractvalue y, n), n -> y
2786 if (Agg == EV->getAggregateOperand())
2793 Value *llvm::SimplifyInsertValueInst(Value *Agg, Value *Val,
2794 ArrayRef<unsigned> Idxs,
2795 const DataLayout *TD,
2796 const TargetLibraryInfo *TLI,
2797 const DominatorTree *DT) {
2798 return ::SimplifyInsertValueInst(Agg, Val, Idxs, Query (TD, TLI, DT),
2802 /// SimplifyPHINode - See if we can fold the given phi. If not, returns null.
2803 static Value *SimplifyPHINode(PHINode *PN, const Query &Q) {
2804 // If all of the PHI's incoming values are the same then replace the PHI node
2805 // with the common value.
2806 Value *CommonValue = 0;
2807 bool HasUndefInput = false;
2808 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
2809 Value *Incoming = PN->getIncomingValue(i);
2810 // If the incoming value is the phi node itself, it can safely be skipped.
2811 if (Incoming == PN) continue;
2812 if (isa<UndefValue>(Incoming)) {
2813 // Remember that we saw an undef value, but otherwise ignore them.
2814 HasUndefInput = true;
2817 if (CommonValue && Incoming != CommonValue)
2818 return 0; // Not the same, bail out.
2819 CommonValue = Incoming;
2822 // If CommonValue is null then all of the incoming values were either undef or
2823 // equal to the phi node itself.
2825 return UndefValue::get(PN->getType());
2827 // If we have a PHI node like phi(X, undef, X), where X is defined by some
2828 // instruction, we cannot return X as the result of the PHI node unless it
2829 // dominates the PHI block.
2831 return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : 0;
2836 static Value *SimplifyTruncInst(Value *Op, Type *Ty, const Query &Q, unsigned) {
2837 if (Constant *C = dyn_cast<Constant>(Op))
2838 return ConstantFoldInstOperands(Instruction::Trunc, Ty, C, Q.TD, Q.TLI);
2843 Value *llvm::SimplifyTruncInst(Value *Op, Type *Ty, const DataLayout *TD,
2844 const TargetLibraryInfo *TLI,
2845 const DominatorTree *DT) {
2846 return ::SimplifyTruncInst(Op, Ty, Query (TD, TLI, DT), RecursionLimit);
2849 //=== Helper functions for higher up the class hierarchy.
2851 /// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
2852 /// fold the result. If not, this returns null.
2853 static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
2854 const Query &Q, unsigned MaxRecurse) {
2856 case Instruction::Add:
2857 return SimplifyAddInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2859 case Instruction::FAdd:
2860 return SimplifyFAddInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
2862 case Instruction::Sub:
2863 return SimplifySubInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2865 case Instruction::FSub:
2866 return SimplifyFSubInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
2868 case Instruction::Mul: return SimplifyMulInst (LHS, RHS, Q, MaxRecurse);
2869 case Instruction::FMul:
2870 return SimplifyFMulInst (LHS, RHS, FastMathFlags(), Q, MaxRecurse);
2871 case Instruction::SDiv: return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
2872 case Instruction::UDiv: return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
2873 case Instruction::FDiv: return SimplifyFDivInst(LHS, RHS, Q, MaxRecurse);
2874 case Instruction::SRem: return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
2875 case Instruction::URem: return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
2876 case Instruction::FRem: return SimplifyFRemInst(LHS, RHS, Q, MaxRecurse);
2877 case Instruction::Shl:
2878 return SimplifyShlInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2880 case Instruction::LShr:
2881 return SimplifyLShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
2882 case Instruction::AShr:
2883 return SimplifyAShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
2884 case Instruction::And: return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
2885 case Instruction::Or: return SimplifyOrInst (LHS, RHS, Q, MaxRecurse);
2886 case Instruction::Xor: return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
2888 if (Constant *CLHS = dyn_cast<Constant>(LHS))
2889 if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
2890 Constant *COps[] = {CLHS, CRHS};
2891 return ConstantFoldInstOperands(Opcode, LHS->getType(), COps, Q.TD,
2895 // If the operation is associative, try some generic simplifications.
2896 if (Instruction::isAssociative(Opcode))
2897 if (Value *V = SimplifyAssociativeBinOp(Opcode, LHS, RHS, Q, MaxRecurse))
2900 // If the operation is with the result of a select instruction check whether
2901 // operating on either branch of the select always yields the same value.
2902 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2903 if (Value *V = ThreadBinOpOverSelect(Opcode, LHS, RHS, Q, MaxRecurse))
2906 // If the operation is with the result of a phi instruction, check whether
2907 // operating on all incoming values of the phi always yields the same value.
2908 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2909 if (Value *V = ThreadBinOpOverPHI(Opcode, LHS, RHS, Q, MaxRecurse))
2916 Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
2917 const DataLayout *TD, const TargetLibraryInfo *TLI,
2918 const DominatorTree *DT) {
2919 return ::SimplifyBinOp(Opcode, LHS, RHS, Query (TD, TLI, DT), RecursionLimit);
2922 /// SimplifyCmpInst - Given operands for a CmpInst, see if we can
2923 /// fold the result.
2924 static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2925 const Query &Q, unsigned MaxRecurse) {
2926 if (CmpInst::isIntPredicate((CmpInst::Predicate)Predicate))
2927 return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
2928 return SimplifyFCmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
2931 Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2932 const DataLayout *TD, const TargetLibraryInfo *TLI,
2933 const DominatorTree *DT) {
2934 return ::SimplifyCmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
2938 static bool IsIdempotent(Intrinsic::ID ID) {
2940 default: return false;
2942 // Unary idempotent: f(f(x)) = f(x)
2943 case Intrinsic::fabs:
2944 case Intrinsic::floor:
2945 case Intrinsic::ceil:
2946 case Intrinsic::trunc:
2947 case Intrinsic::rint:
2948 case Intrinsic::nearbyint:
2949 case Intrinsic::round:
2954 template <typename IterTy>
2955 static Value *SimplifyIntrinsic(Intrinsic::ID IID, IterTy ArgBegin, IterTy ArgEnd,
2956 const Query &Q, unsigned MaxRecurse) {
2957 // Perform idempotent optimizations
2958 if (!IsIdempotent(IID))
2962 if (std::distance(ArgBegin, ArgEnd) == 1)
2963 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(*ArgBegin))
2964 if (II->getIntrinsicID() == IID)
2970 template <typename IterTy>
2971 static Value *SimplifyCall(Value *V, IterTy ArgBegin, IterTy ArgEnd,
2972 const Query &Q, unsigned MaxRecurse) {
2973 Type *Ty = V->getType();
2974 if (PointerType *PTy = dyn_cast<PointerType>(Ty))
2975 Ty = PTy->getElementType();
2976 FunctionType *FTy = cast<FunctionType>(Ty);
2978 // call undef -> undef
2979 if (isa<UndefValue>(V))
2980 return UndefValue::get(FTy->getReturnType());
2982 Function *F = dyn_cast<Function>(V);
2986 if (unsigned IID = F->getIntrinsicID())
2988 SimplifyIntrinsic((Intrinsic::ID) IID, ArgBegin, ArgEnd, Q, MaxRecurse))
2991 if (!canConstantFoldCallTo(F))
2994 SmallVector<Constant *, 4> ConstantArgs;
2995 ConstantArgs.reserve(ArgEnd - ArgBegin);
2996 for (IterTy I = ArgBegin, E = ArgEnd; I != E; ++I) {
2997 Constant *C = dyn_cast<Constant>(*I);
3000 ConstantArgs.push_back(C);
3003 return ConstantFoldCall(F, ConstantArgs, Q.TLI);
3006 Value *llvm::SimplifyCall(Value *V, User::op_iterator ArgBegin,
3007 User::op_iterator ArgEnd, const DataLayout *TD,
3008 const TargetLibraryInfo *TLI,
3009 const DominatorTree *DT) {
3010 return ::SimplifyCall(V, ArgBegin, ArgEnd, Query(TD, TLI, DT),
3014 Value *llvm::SimplifyCall(Value *V, ArrayRef<Value *> Args,
3015 const DataLayout *TD, const TargetLibraryInfo *TLI,
3016 const DominatorTree *DT) {
3017 return ::SimplifyCall(V, Args.begin(), Args.end(), Query(TD, TLI, DT),
3021 /// SimplifyInstruction - See if we can compute a simplified version of this
3022 /// instruction. If not, this returns null.
3023 Value *llvm::SimplifyInstruction(Instruction *I, const DataLayout *TD,
3024 const TargetLibraryInfo *TLI,
3025 const DominatorTree *DT) {
3028 switch (I->getOpcode()) {
3030 Result = ConstantFoldInstruction(I, TD, TLI);
3032 case Instruction::FAdd:
3033 Result = SimplifyFAddInst(I->getOperand(0), I->getOperand(1),
3034 I->getFastMathFlags(), TD, TLI, DT);
3036 case Instruction::Add:
3037 Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
3038 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3039 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3042 case Instruction::FSub:
3043 Result = SimplifyFSubInst(I->getOperand(0), I->getOperand(1),
3044 I->getFastMathFlags(), TD, TLI, DT);
3046 case Instruction::Sub:
3047 Result = SimplifySubInst(I->getOperand(0), I->getOperand(1),
3048 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3049 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3052 case Instruction::FMul:
3053 Result = SimplifyFMulInst(I->getOperand(0), I->getOperand(1),
3054 I->getFastMathFlags(), TD, TLI, DT);
3056 case Instruction::Mul:
3057 Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3059 case Instruction::SDiv:
3060 Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3062 case Instruction::UDiv:
3063 Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3065 case Instruction::FDiv:
3066 Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3068 case Instruction::SRem:
3069 Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3071 case Instruction::URem:
3072 Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3074 case Instruction::FRem:
3075 Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3077 case Instruction::Shl:
3078 Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1),
3079 cast<BinaryOperator>(I)->hasNoSignedWrap(),
3080 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3083 case Instruction::LShr:
3084 Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
3085 cast<BinaryOperator>(I)->isExact(),
3088 case Instruction::AShr:
3089 Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
3090 cast<BinaryOperator>(I)->isExact(),
3093 case Instruction::And:
3094 Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3096 case Instruction::Or:
3097 Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3099 case Instruction::Xor:
3100 Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3102 case Instruction::ICmp:
3103 Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
3104 I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3106 case Instruction::FCmp:
3107 Result = SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(),
3108 I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3110 case Instruction::Select:
3111 Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
3112 I->getOperand(2), TD, TLI, DT);
3114 case Instruction::GetElementPtr: {
3115 SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end());
3116 Result = SimplifyGEPInst(Ops, TD, TLI, DT);
3119 case Instruction::InsertValue: {
3120 InsertValueInst *IV = cast<InsertValueInst>(I);
3121 Result = SimplifyInsertValueInst(IV->getAggregateOperand(),
3122 IV->getInsertedValueOperand(),
3123 IV->getIndices(), TD, TLI, DT);
3126 case Instruction::PHI:
3127 Result = SimplifyPHINode(cast<PHINode>(I), Query (TD, TLI, DT));
3129 case Instruction::Call: {
3130 CallSite CS(cast<CallInst>(I));
3131 Result = SimplifyCall(CS.getCalledValue(), CS.arg_begin(), CS.arg_end(),
3135 case Instruction::Trunc:
3136 Result = SimplifyTruncInst(I->getOperand(0), I->getType(), TD, TLI, DT);
3140 /// If called on unreachable code, the above logic may report that the
3141 /// instruction simplified to itself. Make life easier for users by
3142 /// detecting that case here, returning a safe value instead.
3143 return Result == I ? UndefValue::get(I->getType()) : Result;
3146 /// \brief Implementation of recursive simplification through an instructions
3149 /// This is the common implementation of the recursive simplification routines.
3150 /// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
3151 /// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
3152 /// instructions to process and attempt to simplify it using
3153 /// InstructionSimplify.
3155 /// This routine returns 'true' only when *it* simplifies something. The passed
3156 /// in simplified value does not count toward this.
3157 static bool replaceAndRecursivelySimplifyImpl(Instruction *I, Value *SimpleV,
3158 const DataLayout *TD,
3159 const TargetLibraryInfo *TLI,
3160 const DominatorTree *DT) {
3161 bool Simplified = false;
3162 SmallSetVector<Instruction *, 8> Worklist;
3164 // If we have an explicit value to collapse to, do that round of the
3165 // simplification loop by hand initially.
3167 for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE;
3170 Worklist.insert(cast<Instruction>(*UI));
3172 // Replace the instruction with its simplified value.
3173 I->replaceAllUsesWith(SimpleV);
3175 // Gracefully handle edge cases where the instruction is not wired into any
3178 I->eraseFromParent();
3183 // Note that we must test the size on each iteration, the worklist can grow.
3184 for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
3187 // See if this instruction simplifies.
3188 SimpleV = SimplifyInstruction(I, TD, TLI, DT);
3194 // Stash away all the uses of the old instruction so we can check them for
3195 // recursive simplifications after a RAUW. This is cheaper than checking all
3196 // uses of To on the recursive step in most cases.
3197 for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE;
3199 Worklist.insert(cast<Instruction>(*UI));
3201 // Replace the instruction with its simplified value.
3202 I->replaceAllUsesWith(SimpleV);
3204 // Gracefully handle edge cases where the instruction is not wired into any
3207 I->eraseFromParent();
3212 bool llvm::recursivelySimplifyInstruction(Instruction *I,
3213 const DataLayout *TD,
3214 const TargetLibraryInfo *TLI,
3215 const DominatorTree *DT) {
3216 return replaceAndRecursivelySimplifyImpl(I, 0, TD, TLI, DT);
3219 bool llvm::replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV,
3220 const DataLayout *TD,
3221 const TargetLibraryInfo *TLI,
3222 const DominatorTree *DT) {
3223 assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!");
3224 assert(SimpleV && "Must provide a simplified value.");
3225 return replaceAndRecursivelySimplifyImpl(I, SimpleV, TD, TLI, DT);