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 ConstantInt *stripAndComputeConstantOffsets(const DataLayout *TD,
672 assert(V->getType()->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 unsigned IntPtrWidth = TD->getPointerSizeInBits();
680 APInt Offset = APInt::getNullValue(IntPtrWidth);
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()->isPointerTy() && "Unexpected operand type!");
701 } while (Visited.insert(V));
703 Type *IntPtrTy = TD->getIntPtrType(V->getContext());
704 return cast<ConstantInt>(ConstantInt::get(IntPtrTy, Offset));
707 /// \brief Compute the constant difference between two pointer values.
708 /// If the difference is not a constant, returns zero.
709 static Constant *computePointerDifference(const DataLayout *TD,
710 Value *LHS, Value *RHS) {
711 Constant *LHSOffset = stripAndComputeConstantOffsets(TD, LHS);
712 Constant *RHSOffset = stripAndComputeConstantOffsets(TD, RHS);
714 // If LHS and RHS are not related via constant offsets to the same base
715 // value, there is nothing we can do here.
719 // Otherwise, the difference of LHS - RHS can be computed as:
721 // = (LHSOffset + Base) - (RHSOffset + Base)
722 // = LHSOffset - RHSOffset
723 return ConstantExpr::getSub(LHSOffset, RHSOffset);
726 /// SimplifySubInst - Given operands for a Sub, see if we can
727 /// fold the result. If not, this returns null.
728 static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
729 const Query &Q, unsigned MaxRecurse) {
730 if (Constant *CLHS = dyn_cast<Constant>(Op0))
731 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
732 Constant *Ops[] = { CLHS, CRHS };
733 return ConstantFoldInstOperands(Instruction::Sub, CLHS->getType(),
737 // X - undef -> undef
738 // undef - X -> undef
739 if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
740 return UndefValue::get(Op0->getType());
743 if (match(Op1, m_Zero()))
748 return Constant::getNullValue(Op0->getType());
753 if (match(Op0, m_Mul(m_Specific(Op1), m_ConstantInt<2>())) ||
754 match(Op0, m_Shl(m_Specific(Op1), m_One())))
757 // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
758 // For example, (X + Y) - Y -> X; (Y + X) - Y -> X
759 Value *Y = 0, *Z = Op1;
760 if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z
761 // See if "V === Y - Z" simplifies.
762 if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, Q, MaxRecurse-1))
763 // It does! Now see if "X + V" simplifies.
764 if (Value *W = SimplifyBinOp(Instruction::Add, X, V, Q, MaxRecurse-1)) {
765 // It does, we successfully reassociated!
769 // See if "V === X - Z" simplifies.
770 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
771 // It does! Now see if "Y + V" simplifies.
772 if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, Q, MaxRecurse-1)) {
773 // It does, we successfully reassociated!
779 // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
780 // For example, X - (X + 1) -> -1
782 if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z)
783 // See if "V === X - Y" simplifies.
784 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
785 // It does! Now see if "V - Z" simplifies.
786 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, Q, MaxRecurse-1)) {
787 // It does, we successfully reassociated!
791 // See if "V === X - Z" simplifies.
792 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
793 // It does! Now see if "V - Y" simplifies.
794 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, Q, MaxRecurse-1)) {
795 // It does, we successfully reassociated!
801 // Z - (X - Y) -> (Z - X) + Y if everything simplifies.
802 // For example, X - (X - Y) -> Y.
804 if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y)
805 // See if "V === Z - X" simplifies.
806 if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, Q, MaxRecurse-1))
807 // It does! Now see if "V + Y" simplifies.
808 if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, Q, MaxRecurse-1)) {
809 // It does, we successfully reassociated!
814 // trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies.
815 if (MaxRecurse && match(Op0, m_Trunc(m_Value(X))) &&
816 match(Op1, m_Trunc(m_Value(Y))))
817 if (X->getType() == Y->getType())
818 // See if "V === X - Y" simplifies.
819 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
820 // It does! Now see if "trunc V" simplifies.
821 if (Value *W = SimplifyTruncInst(V, Op0->getType(), Q, MaxRecurse-1))
822 // It does, return the simplified "trunc V".
825 // Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...).
826 if (match(Op0, m_PtrToInt(m_Value(X))) &&
827 match(Op1, m_PtrToInt(m_Value(Y))))
828 if (Constant *Result = computePointerDifference(Q.TD, X, Y))
829 return ConstantExpr::getIntegerCast(Result, Op0->getType(), true);
831 // Mul distributes over Sub. Try some generic simplifications based on this.
832 if (Value *V = FactorizeBinOp(Instruction::Sub, Op0, Op1, Instruction::Mul,
837 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
838 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
841 // Threading Sub over selects and phi nodes is pointless, so don't bother.
842 // Threading over the select in "A - select(cond, B, C)" means evaluating
843 // "A-B" and "A-C" and seeing if they are equal; but they are equal if and
844 // only if B and C are equal. If B and C are equal then (since we assume
845 // that operands have already been simplified) "select(cond, B, C)" should
846 // have been simplified to the common value of B and C already. Analysing
847 // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly
848 // for threading over phi nodes.
853 Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
854 const DataLayout *TD, const TargetLibraryInfo *TLI,
855 const DominatorTree *DT) {
856 return ::SimplifySubInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT),
860 /// Given operands for an FAdd, see if we can fold the result. If not, this
862 static Value *SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
863 const Query &Q, unsigned MaxRecurse) {
864 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
865 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
866 Constant *Ops[] = { CLHS, CRHS };
867 return ConstantFoldInstOperands(Instruction::FAdd, CLHS->getType(),
871 // Canonicalize the constant to the RHS.
876 if (match(Op1, m_NegZero()))
879 // fadd X, 0 ==> X, when we know X is not -0
880 if (match(Op1, m_Zero()) &&
881 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
884 // fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
885 // where nnan and ninf have to occur at least once somewhere in this
888 if (match(Op1, m_FSub(m_AnyZero(), m_Specific(Op0))))
890 else if (match(Op0, m_FSub(m_AnyZero(), m_Specific(Op1))))
893 Instruction *FSub = cast<Instruction>(SubOp);
894 if ((FMF.noNaNs() || FSub->hasNoNaNs()) &&
895 (FMF.noInfs() || FSub->hasNoInfs()))
896 return Constant::getNullValue(Op0->getType());
902 /// Given operands for an FSub, see if we can fold the result. If not, this
904 static Value *SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
905 const Query &Q, unsigned MaxRecurse) {
906 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
907 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
908 Constant *Ops[] = { CLHS, CRHS };
909 return ConstantFoldInstOperands(Instruction::FSub, CLHS->getType(),
915 if (match(Op1, m_Zero()))
918 // fsub X, -0 ==> X, when we know X is not -0
919 if (match(Op1, m_NegZero()) &&
920 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0)))
923 // fsub 0, (fsub -0.0, X) ==> X
925 if (match(Op0, m_AnyZero())) {
926 if (match(Op1, m_FSub(m_NegZero(), m_Value(X))))
928 if (FMF.noSignedZeros() && match(Op1, m_FSub(m_AnyZero(), m_Value(X))))
932 // fsub nnan ninf x, x ==> 0.0
933 if (FMF.noNaNs() && FMF.noInfs() && Op0 == Op1)
934 return Constant::getNullValue(Op0->getType());
939 /// Given the operands for an FMul, see if we can fold the result
940 static Value *SimplifyFMulInst(Value *Op0, Value *Op1,
943 unsigned MaxRecurse) {
944 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
945 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
946 Constant *Ops[] = { CLHS, CRHS };
947 return ConstantFoldInstOperands(Instruction::FMul, CLHS->getType(),
951 // Canonicalize the constant to the RHS.
956 if (match(Op1, m_FPOne()))
959 // fmul nnan nsz X, 0 ==> 0
960 if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZero()))
966 /// SimplifyMulInst - Given operands for a Mul, see if we can
967 /// fold the result. If not, this returns null.
968 static Value *SimplifyMulInst(Value *Op0, Value *Op1, const Query &Q,
969 unsigned MaxRecurse) {
970 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
971 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
972 Constant *Ops[] = { CLHS, CRHS };
973 return ConstantFoldInstOperands(Instruction::Mul, CLHS->getType(),
977 // Canonicalize the constant to the RHS.
982 if (match(Op1, m_Undef()))
983 return Constant::getNullValue(Op0->getType());
986 if (match(Op1, m_Zero()))
990 if (match(Op1, m_One()))
993 // (X / Y) * Y -> X if the division is exact.
995 if (match(Op0, m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y
996 match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0))))) // Y * (X / Y)
1000 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
1001 if (Value *V = SimplifyAndInst(Op0, Op1, Q, MaxRecurse-1))
1004 // Try some generic simplifications for associative operations.
1005 if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, Q,
1009 // Mul distributes over Add. Try some generic simplifications based on this.
1010 if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add,
1014 // If the operation is with the result of a select instruction, check whether
1015 // operating on either branch of the select always yields the same value.
1016 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1017 if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, Q,
1021 // If the operation is with the result of a phi instruction, check whether
1022 // operating on all incoming values of the phi always yields the same value.
1023 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1024 if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, Q,
1031 Value *llvm::SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
1032 const DataLayout *TD, const TargetLibraryInfo *TLI,
1033 const DominatorTree *DT) {
1034 return ::SimplifyFAddInst(Op0, Op1, FMF, Query (TD, TLI, DT), RecursionLimit);
1037 Value *llvm::SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
1038 const DataLayout *TD, const TargetLibraryInfo *TLI,
1039 const DominatorTree *DT) {
1040 return ::SimplifyFSubInst(Op0, Op1, FMF, Query (TD, TLI, DT), RecursionLimit);
1043 Value *llvm::SimplifyFMulInst(Value *Op0, Value *Op1,
1045 const DataLayout *TD,
1046 const TargetLibraryInfo *TLI,
1047 const DominatorTree *DT) {
1048 return ::SimplifyFMulInst(Op0, Op1, FMF, Query (TD, TLI, DT), RecursionLimit);
1051 Value *llvm::SimplifyMulInst(Value *Op0, Value *Op1, const DataLayout *TD,
1052 const TargetLibraryInfo *TLI,
1053 const DominatorTree *DT) {
1054 return ::SimplifyMulInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1057 /// SimplifyDiv - Given operands for an SDiv or UDiv, see if we can
1058 /// fold the result. If not, this returns null.
1059 static Value *SimplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
1060 const Query &Q, unsigned MaxRecurse) {
1061 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1062 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1063 Constant *Ops[] = { C0, C1 };
1064 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI);
1068 bool isSigned = Opcode == Instruction::SDiv;
1070 // X / undef -> undef
1071 if (match(Op1, m_Undef()))
1075 if (match(Op0, m_Undef()))
1076 return Constant::getNullValue(Op0->getType());
1078 // 0 / X -> 0, we don't need to preserve faults!
1079 if (match(Op0, m_Zero()))
1083 if (match(Op1, m_One()))
1086 if (Op0->getType()->isIntegerTy(1))
1087 // It can't be division by zero, hence it must be division by one.
1092 return ConstantInt::get(Op0->getType(), 1);
1094 // (X * Y) / Y -> X if the multiplication does not overflow.
1095 Value *X = 0, *Y = 0;
1096 if (match(Op0, m_Mul(m_Value(X), m_Value(Y))) && (X == Op1 || Y == Op1)) {
1097 if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1
1098 OverflowingBinaryOperator *Mul = cast<OverflowingBinaryOperator>(Op0);
1099 // If the Mul knows it does not overflow, then we are good to go.
1100 if ((isSigned && Mul->hasNoSignedWrap()) ||
1101 (!isSigned && Mul->hasNoUnsignedWrap()))
1103 // If X has the form X = A / Y then X * Y cannot overflow.
1104 if (BinaryOperator *Div = dyn_cast<BinaryOperator>(X))
1105 if (Div->getOpcode() == Opcode && Div->getOperand(1) == Y)
1109 // (X rem Y) / Y -> 0
1110 if ((isSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1111 (!isSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1112 return Constant::getNullValue(Op0->getType());
1114 // If the operation is with the result of a select instruction, check whether
1115 // operating on either branch of the select always yields the same value.
1116 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1117 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1120 // If the operation is with the result of a phi instruction, check whether
1121 // operating on all incoming values of the phi always yields the same value.
1122 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1123 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1129 /// SimplifySDivInst - Given operands for an SDiv, see if we can
1130 /// fold the result. If not, this returns null.
1131 static Value *SimplifySDivInst(Value *Op0, Value *Op1, const Query &Q,
1132 unsigned MaxRecurse) {
1133 if (Value *V = SimplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse))
1139 Value *llvm::SimplifySDivInst(Value *Op0, Value *Op1, const DataLayout *TD,
1140 const TargetLibraryInfo *TLI,
1141 const DominatorTree *DT) {
1142 return ::SimplifySDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1145 /// SimplifyUDivInst - Given operands for a UDiv, see if we can
1146 /// fold the result. If not, this returns null.
1147 static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const Query &Q,
1148 unsigned MaxRecurse) {
1149 if (Value *V = SimplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse))
1155 Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const DataLayout *TD,
1156 const TargetLibraryInfo *TLI,
1157 const DominatorTree *DT) {
1158 return ::SimplifyUDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1161 static Value *SimplifyFDivInst(Value *Op0, Value *Op1, const Query &Q,
1163 // undef / X -> undef (the undef could be a snan).
1164 if (match(Op0, m_Undef()))
1167 // X / undef -> undef
1168 if (match(Op1, m_Undef()))
1174 Value *llvm::SimplifyFDivInst(Value *Op0, Value *Op1, const DataLayout *TD,
1175 const TargetLibraryInfo *TLI,
1176 const DominatorTree *DT) {
1177 return ::SimplifyFDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1180 /// SimplifyRem - Given operands for an SRem or URem, see if we can
1181 /// fold the result. If not, this returns null.
1182 static Value *SimplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
1183 const Query &Q, unsigned MaxRecurse) {
1184 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1185 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1186 Constant *Ops[] = { C0, C1 };
1187 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI);
1191 // X % undef -> undef
1192 if (match(Op1, m_Undef()))
1196 if (match(Op0, m_Undef()))
1197 return Constant::getNullValue(Op0->getType());
1199 // 0 % X -> 0, we don't need to preserve faults!
1200 if (match(Op0, m_Zero()))
1203 // X % 0 -> undef, we don't need to preserve faults!
1204 if (match(Op1, m_Zero()))
1205 return UndefValue::get(Op0->getType());
1208 if (match(Op1, m_One()))
1209 return Constant::getNullValue(Op0->getType());
1211 if (Op0->getType()->isIntegerTy(1))
1212 // It can't be remainder by zero, hence it must be remainder by one.
1213 return Constant::getNullValue(Op0->getType());
1217 return Constant::getNullValue(Op0->getType());
1219 // If the operation is with the result of a select instruction, check whether
1220 // operating on either branch of the select always yields the same value.
1221 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1222 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1225 // If the operation is with the result of a phi instruction, check whether
1226 // operating on all incoming values of the phi always yields the same value.
1227 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1228 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1234 /// SimplifySRemInst - Given operands for an SRem, see if we can
1235 /// fold the result. If not, this returns null.
1236 static Value *SimplifySRemInst(Value *Op0, Value *Op1, const Query &Q,
1237 unsigned MaxRecurse) {
1238 if (Value *V = SimplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse))
1244 Value *llvm::SimplifySRemInst(Value *Op0, Value *Op1, const DataLayout *TD,
1245 const TargetLibraryInfo *TLI,
1246 const DominatorTree *DT) {
1247 return ::SimplifySRemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1250 /// SimplifyURemInst - Given operands for a URem, see if we can
1251 /// fold the result. If not, this returns null.
1252 static Value *SimplifyURemInst(Value *Op0, Value *Op1, const Query &Q,
1253 unsigned MaxRecurse) {
1254 if (Value *V = SimplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse))
1260 Value *llvm::SimplifyURemInst(Value *Op0, Value *Op1, const DataLayout *TD,
1261 const TargetLibraryInfo *TLI,
1262 const DominatorTree *DT) {
1263 return ::SimplifyURemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1266 static Value *SimplifyFRemInst(Value *Op0, Value *Op1, const Query &,
1268 // undef % X -> undef (the undef could be a snan).
1269 if (match(Op0, m_Undef()))
1272 // X % undef -> undef
1273 if (match(Op1, m_Undef()))
1279 Value *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, const DataLayout *TD,
1280 const TargetLibraryInfo *TLI,
1281 const DominatorTree *DT) {
1282 return ::SimplifyFRemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1285 /// SimplifyShift - Given operands for an Shl, LShr or AShr, see if we can
1286 /// fold the result. If not, this returns null.
1287 static Value *SimplifyShift(unsigned Opcode, Value *Op0, Value *Op1,
1288 const Query &Q, unsigned MaxRecurse) {
1289 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1290 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1291 Constant *Ops[] = { C0, C1 };
1292 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI);
1296 // 0 shift by X -> 0
1297 if (match(Op0, m_Zero()))
1300 // X shift by 0 -> X
1301 if (match(Op1, m_Zero()))
1304 // X shift by undef -> undef because it may shift by the bitwidth.
1305 if (match(Op1, m_Undef()))
1308 // Shifting by the bitwidth or more is undefined.
1309 if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1))
1310 if (CI->getValue().getLimitedValue() >=
1311 Op0->getType()->getScalarSizeInBits())
1312 return UndefValue::get(Op0->getType());
1314 // If the operation is with the result of a select instruction, check whether
1315 // operating on either branch of the select always yields the same value.
1316 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1317 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1320 // If the operation is with the result of a phi instruction, check whether
1321 // operating on all incoming values of the phi always yields the same value.
1322 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1323 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1329 /// SimplifyShlInst - Given operands for an Shl, see if we can
1330 /// fold the result. If not, this returns null.
1331 static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1332 const Query &Q, unsigned MaxRecurse) {
1333 if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse))
1337 if (match(Op0, m_Undef()))
1338 return Constant::getNullValue(Op0->getType());
1340 // (X >> A) << A -> X
1342 if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
1347 Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1348 const DataLayout *TD, const TargetLibraryInfo *TLI,
1349 const DominatorTree *DT) {
1350 return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT),
1354 /// SimplifyLShrInst - Given operands for an LShr, see if we can
1355 /// fold the result. If not, this returns null.
1356 static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1357 const Query &Q, unsigned MaxRecurse) {
1358 if (Value *V = SimplifyShift(Instruction::LShr, Op0, Op1, Q, MaxRecurse))
1362 if (match(Op0, m_Undef()))
1363 return Constant::getNullValue(Op0->getType());
1365 // (X << A) >> A -> X
1367 if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) &&
1368 cast<OverflowingBinaryOperator>(Op0)->hasNoUnsignedWrap())
1374 Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1375 const DataLayout *TD,
1376 const TargetLibraryInfo *TLI,
1377 const DominatorTree *DT) {
1378 return ::SimplifyLShrInst(Op0, Op1, isExact, Query (TD, TLI, DT),
1382 /// SimplifyAShrInst - Given operands for an AShr, see if we can
1383 /// fold the result. If not, this returns null.
1384 static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1385 const Query &Q, unsigned MaxRecurse) {
1386 if (Value *V = SimplifyShift(Instruction::AShr, Op0, Op1, Q, MaxRecurse))
1389 // all ones >>a X -> all ones
1390 if (match(Op0, m_AllOnes()))
1393 // undef >>a X -> all ones
1394 if (match(Op0, m_Undef()))
1395 return Constant::getAllOnesValue(Op0->getType());
1397 // (X << A) >> A -> X
1399 if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) &&
1400 cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap())
1406 Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1407 const DataLayout *TD,
1408 const TargetLibraryInfo *TLI,
1409 const DominatorTree *DT) {
1410 return ::SimplifyAShrInst(Op0, Op1, isExact, Query (TD, TLI, DT),
1414 /// SimplifyAndInst - Given operands for an And, see if we can
1415 /// fold the result. If not, this returns null.
1416 static Value *SimplifyAndInst(Value *Op0, Value *Op1, const Query &Q,
1417 unsigned MaxRecurse) {
1418 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1419 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1420 Constant *Ops[] = { CLHS, CRHS };
1421 return ConstantFoldInstOperands(Instruction::And, CLHS->getType(),
1425 // Canonicalize the constant to the RHS.
1426 std::swap(Op0, Op1);
1430 if (match(Op1, m_Undef()))
1431 return Constant::getNullValue(Op0->getType());
1438 if (match(Op1, m_Zero()))
1442 if (match(Op1, m_AllOnes()))
1445 // A & ~A = ~A & A = 0
1446 if (match(Op0, m_Not(m_Specific(Op1))) ||
1447 match(Op1, m_Not(m_Specific(Op0))))
1448 return Constant::getNullValue(Op0->getType());
1451 Value *A = 0, *B = 0;
1452 if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
1453 (A == Op1 || B == Op1))
1457 if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
1458 (A == Op0 || B == Op0))
1461 // A & (-A) = A if A is a power of two or zero.
1462 if (match(Op0, m_Neg(m_Specific(Op1))) ||
1463 match(Op1, m_Neg(m_Specific(Op0)))) {
1464 if (isKnownToBeAPowerOfTwo(Op0, /*OrZero*/true))
1466 if (isKnownToBeAPowerOfTwo(Op1, /*OrZero*/true))
1470 // Try some generic simplifications for associative operations.
1471 if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
1475 // And distributes over Or. Try some generic simplifications based on this.
1476 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1480 // And distributes over Xor. Try some generic simplifications based on this.
1481 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
1485 // Or distributes over And. Try some generic simplifications based on this.
1486 if (Value *V = FactorizeBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1490 // If the operation is with the result of a select instruction, check whether
1491 // operating on either branch of the select always yields the same value.
1492 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1493 if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
1497 // If the operation is with the result of a phi instruction, check whether
1498 // operating on all incoming values of the phi always yields the same value.
1499 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1500 if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
1507 Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const DataLayout *TD,
1508 const TargetLibraryInfo *TLI,
1509 const DominatorTree *DT) {
1510 return ::SimplifyAndInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1513 /// SimplifyOrInst - Given operands for an Or, see if we can
1514 /// fold the result. If not, this returns null.
1515 static Value *SimplifyOrInst(Value *Op0, Value *Op1, const Query &Q,
1516 unsigned MaxRecurse) {
1517 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1518 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1519 Constant *Ops[] = { CLHS, CRHS };
1520 return ConstantFoldInstOperands(Instruction::Or, CLHS->getType(),
1524 // Canonicalize the constant to the RHS.
1525 std::swap(Op0, Op1);
1529 if (match(Op1, m_Undef()))
1530 return Constant::getAllOnesValue(Op0->getType());
1537 if (match(Op1, m_Zero()))
1541 if (match(Op1, m_AllOnes()))
1544 // A | ~A = ~A | A = -1
1545 if (match(Op0, m_Not(m_Specific(Op1))) ||
1546 match(Op1, m_Not(m_Specific(Op0))))
1547 return Constant::getAllOnesValue(Op0->getType());
1550 Value *A = 0, *B = 0;
1551 if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
1552 (A == Op1 || B == Op1))
1556 if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
1557 (A == Op0 || B == Op0))
1560 // ~(A & ?) | A = -1
1561 if (match(Op0, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1562 (A == Op1 || B == Op1))
1563 return Constant::getAllOnesValue(Op1->getType());
1565 // A | ~(A & ?) = -1
1566 if (match(Op1, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1567 (A == Op0 || B == Op0))
1568 return Constant::getAllOnesValue(Op0->getType());
1570 // Try some generic simplifications for associative operations.
1571 if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
1575 // Or distributes over And. Try some generic simplifications based on this.
1576 if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
1580 // And distributes over Or. Try some generic simplifications based on this.
1581 if (Value *V = FactorizeBinOp(Instruction::Or, Op0, Op1, Instruction::And,
1585 // If the operation is with the result of a select instruction, check whether
1586 // operating on either branch of the select always yields the same value.
1587 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1588 if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
1592 // If the operation is with the result of a phi instruction, check whether
1593 // operating on all incoming values of the phi always yields the same value.
1594 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1595 if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
1601 Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const DataLayout *TD,
1602 const TargetLibraryInfo *TLI,
1603 const DominatorTree *DT) {
1604 return ::SimplifyOrInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1607 /// SimplifyXorInst - Given operands for a Xor, see if we can
1608 /// fold the result. If not, this returns null.
1609 static Value *SimplifyXorInst(Value *Op0, Value *Op1, const Query &Q,
1610 unsigned MaxRecurse) {
1611 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1612 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1613 Constant *Ops[] = { CLHS, CRHS };
1614 return ConstantFoldInstOperands(Instruction::Xor, CLHS->getType(),
1618 // Canonicalize the constant to the RHS.
1619 std::swap(Op0, Op1);
1622 // A ^ undef -> undef
1623 if (match(Op1, m_Undef()))
1627 if (match(Op1, m_Zero()))
1632 return Constant::getNullValue(Op0->getType());
1634 // A ^ ~A = ~A ^ A = -1
1635 if (match(Op0, m_Not(m_Specific(Op1))) ||
1636 match(Op1, m_Not(m_Specific(Op0))))
1637 return Constant::getAllOnesValue(Op0->getType());
1639 // Try some generic simplifications for associative operations.
1640 if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
1644 // And distributes over Xor. Try some generic simplifications based on this.
1645 if (Value *V = FactorizeBinOp(Instruction::Xor, Op0, Op1, Instruction::And,
1649 // Threading Xor over selects and phi nodes is pointless, so don't bother.
1650 // Threading over the select in "A ^ select(cond, B, C)" means evaluating
1651 // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
1652 // only if B and C are equal. If B and C are equal then (since we assume
1653 // that operands have already been simplified) "select(cond, B, C)" should
1654 // have been simplified to the common value of B and C already. Analysing
1655 // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
1656 // for threading over phi nodes.
1661 Value *llvm::SimplifyXorInst(Value *Op0, Value *Op1, const DataLayout *TD,
1662 const TargetLibraryInfo *TLI,
1663 const DominatorTree *DT) {
1664 return ::SimplifyXorInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1667 static Type *GetCompareTy(Value *Op) {
1668 return CmpInst::makeCmpResultType(Op->getType());
1671 /// ExtractEquivalentCondition - Rummage around inside V looking for something
1672 /// equivalent to the comparison "LHS Pred RHS". Return such a value if found,
1673 /// otherwise return null. Helper function for analyzing max/min idioms.
1674 static Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred,
1675 Value *LHS, Value *RHS) {
1676 SelectInst *SI = dyn_cast<SelectInst>(V);
1679 CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
1682 Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
1683 if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
1685 if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
1686 LHS == CmpRHS && RHS == CmpLHS)
1691 static Constant *computePointerICmp(const DataLayout *TD,
1692 const TargetLibraryInfo *TLI,
1693 CmpInst::Predicate Pred,
1694 Value *LHS, Value *RHS) {
1695 // First, skip past any trivial no-ops.
1696 LHS = LHS->stripPointerCasts();
1697 RHS = RHS->stripPointerCasts();
1699 // A non-null pointer is not equal to a null pointer.
1700 if (llvm::isKnownNonNull(LHS) && isa<ConstantPointerNull>(RHS) &&
1701 (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE))
1702 return ConstantInt::get(GetCompareTy(LHS),
1703 !CmpInst::isTrueWhenEqual(Pred));
1705 // We can only fold certain predicates on pointer comparisons.
1710 // Equality comaprisons are easy to fold.
1711 case CmpInst::ICMP_EQ:
1712 case CmpInst::ICMP_NE:
1715 // We can only handle unsigned relational comparisons because 'inbounds' on
1716 // a GEP only protects against unsigned wrapping.
1717 case CmpInst::ICMP_UGT:
1718 case CmpInst::ICMP_UGE:
1719 case CmpInst::ICMP_ULT:
1720 case CmpInst::ICMP_ULE:
1721 // However, we have to switch them to their signed variants to handle
1722 // negative indices from the base pointer.
1723 Pred = ICmpInst::getSignedPredicate(Pred);
1727 // Strip off any constant offsets so that we can reason about them.
1728 // It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets
1729 // here and compare base addresses like AliasAnalysis does, however there are
1730 // numerous hazards. AliasAnalysis and its utilities rely on special rules
1731 // governing loads and stores which don't apply to icmps. Also, AliasAnalysis
1732 // doesn't need to guarantee pointer inequality when it says NoAlias.
1733 ConstantInt *LHSOffset = stripAndComputeConstantOffsets(TD, LHS);
1734 ConstantInt *RHSOffset = stripAndComputeConstantOffsets(TD, RHS);
1736 // If LHS and RHS are related via constant offsets to the same base
1737 // value, we can replace it with an icmp which just compares the offsets.
1739 return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset);
1741 // Various optimizations for (in)equality comparisons.
1742 if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE) {
1743 // Different non-empty allocations that exist at the same time have
1744 // different addresses (if the program can tell). Global variables always
1745 // exist, so they always exist during the lifetime of each other and all
1746 // allocas. Two different allocas usually have different addresses...
1748 // However, if there's an @llvm.stackrestore dynamically in between two
1749 // allocas, they may have the same address. It's tempting to reduce the
1750 // scope of the problem by only looking at *static* allocas here. That would
1751 // cover the majority of allocas while significantly reducing the likelihood
1752 // of having an @llvm.stackrestore pop up in the middle. However, it's not
1753 // actually impossible for an @llvm.stackrestore to pop up in the middle of
1754 // an entry block. Also, if we have a block that's not attached to a
1755 // function, we can't tell if it's "static" under the current definition.
1756 // Theoretically, this problem could be fixed by creating a new kind of
1757 // instruction kind specifically for static allocas. Such a new instruction
1758 // could be required to be at the top of the entry block, thus preventing it
1759 // from being subject to a @llvm.stackrestore. Instcombine could even
1760 // convert regular allocas into these special allocas. It'd be nifty.
1761 // However, until then, this problem remains open.
1763 // So, we'll assume that two non-empty allocas have different addresses
1766 // With all that, if the offsets are within the bounds of their allocations
1767 // (and not one-past-the-end! so we can't use inbounds!), and their
1768 // allocations aren't the same, the pointers are not equal.
1770 // Note that it's not necessary to check for LHS being a global variable
1771 // address, due to canonicalization and constant folding.
1772 if (isa<AllocaInst>(LHS) &&
1773 (isa<AllocaInst>(RHS) || isa<GlobalVariable>(RHS))) {
1774 uint64_t LHSSize, RHSSize;
1775 if (getObjectSize(LHS, LHSSize, TD, TLI) &&
1776 getObjectSize(RHS, RHSSize, TD, TLI)) {
1777 const APInt &LHSOffsetValue = LHSOffset->getValue();
1778 const APInt &RHSOffsetValue = RHSOffset->getValue();
1779 if (!LHSOffsetValue.isNegative() &&
1780 !RHSOffsetValue.isNegative() &&
1781 LHSOffsetValue.ult(LHSSize) &&
1782 RHSOffsetValue.ult(RHSSize)) {
1783 return ConstantInt::get(GetCompareTy(LHS),
1784 !CmpInst::isTrueWhenEqual(Pred));
1788 // Repeat the above check but this time without depending on DataLayout
1789 // or being able to compute a precise size.
1790 if (!cast<PointerType>(LHS->getType())->isEmptyTy() &&
1791 !cast<PointerType>(RHS->getType())->isEmptyTy() &&
1792 LHSOffset->isNullValue() &&
1793 RHSOffset->isNullValue())
1794 return ConstantInt::get(GetCompareTy(LHS),
1795 !CmpInst::isTrueWhenEqual(Pred));
1803 /// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
1804 /// fold the result. If not, this returns null.
1805 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
1806 const Query &Q, unsigned MaxRecurse) {
1807 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
1808 assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
1810 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
1811 if (Constant *CRHS = dyn_cast<Constant>(RHS))
1812 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.TD, Q.TLI);
1814 // If we have a constant, make sure it is on the RHS.
1815 std::swap(LHS, RHS);
1816 Pred = CmpInst::getSwappedPredicate(Pred);
1819 Type *ITy = GetCompareTy(LHS); // The return type.
1820 Type *OpTy = LHS->getType(); // The operand type.
1822 // icmp X, X -> true/false
1823 // X icmp undef -> true/false. For example, icmp ugt %X, undef -> false
1824 // because X could be 0.
1825 if (LHS == RHS || isa<UndefValue>(RHS))
1826 return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
1828 // Special case logic when the operands have i1 type.
1829 if (OpTy->getScalarType()->isIntegerTy(1)) {
1832 case ICmpInst::ICMP_EQ:
1834 if (match(RHS, m_One()))
1837 case ICmpInst::ICMP_NE:
1839 if (match(RHS, m_Zero()))
1842 case ICmpInst::ICMP_UGT:
1844 if (match(RHS, m_Zero()))
1847 case ICmpInst::ICMP_UGE:
1849 if (match(RHS, m_One()))
1852 case ICmpInst::ICMP_SLT:
1854 if (match(RHS, m_Zero()))
1857 case ICmpInst::ICMP_SLE:
1859 if (match(RHS, m_One()))
1865 // If we are comparing with zero then try hard since this is a common case.
1866 if (match(RHS, m_Zero())) {
1867 bool LHSKnownNonNegative, LHSKnownNegative;
1869 default: llvm_unreachable("Unknown ICmp predicate!");
1870 case ICmpInst::ICMP_ULT:
1871 return getFalse(ITy);
1872 case ICmpInst::ICMP_UGE:
1873 return getTrue(ITy);
1874 case ICmpInst::ICMP_EQ:
1875 case ICmpInst::ICMP_ULE:
1876 if (isKnownNonZero(LHS, Q.TD))
1877 return getFalse(ITy);
1879 case ICmpInst::ICMP_NE:
1880 case ICmpInst::ICMP_UGT:
1881 if (isKnownNonZero(LHS, Q.TD))
1882 return getTrue(ITy);
1884 case ICmpInst::ICMP_SLT:
1885 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1886 if (LHSKnownNegative)
1887 return getTrue(ITy);
1888 if (LHSKnownNonNegative)
1889 return getFalse(ITy);
1891 case ICmpInst::ICMP_SLE:
1892 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1893 if (LHSKnownNegative)
1894 return getTrue(ITy);
1895 if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.TD))
1896 return getFalse(ITy);
1898 case ICmpInst::ICMP_SGE:
1899 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1900 if (LHSKnownNegative)
1901 return getFalse(ITy);
1902 if (LHSKnownNonNegative)
1903 return getTrue(ITy);
1905 case ICmpInst::ICMP_SGT:
1906 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1907 if (LHSKnownNegative)
1908 return getFalse(ITy);
1909 if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.TD))
1910 return getTrue(ITy);
1915 // See if we are doing a comparison with a constant integer.
1916 if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
1917 // Rule out tautological comparisons (eg., ult 0 or uge 0).
1918 ConstantRange RHS_CR = ICmpInst::makeConstantRange(Pred, CI->getValue());
1919 if (RHS_CR.isEmptySet())
1920 return ConstantInt::getFalse(CI->getContext());
1921 if (RHS_CR.isFullSet())
1922 return ConstantInt::getTrue(CI->getContext());
1924 // Many binary operators with constant RHS have easy to compute constant
1925 // range. Use them to check whether the comparison is a tautology.
1926 uint32_t Width = CI->getBitWidth();
1927 APInt Lower = APInt(Width, 0);
1928 APInt Upper = APInt(Width, 0);
1930 if (match(LHS, m_URem(m_Value(), m_ConstantInt(CI2)))) {
1931 // 'urem x, CI2' produces [0, CI2).
1932 Upper = CI2->getValue();
1933 } else if (match(LHS, m_SRem(m_Value(), m_ConstantInt(CI2)))) {
1934 // 'srem x, CI2' produces (-|CI2|, |CI2|).
1935 Upper = CI2->getValue().abs();
1936 Lower = (-Upper) + 1;
1937 } else if (match(LHS, m_UDiv(m_ConstantInt(CI2), m_Value()))) {
1938 // 'udiv CI2, x' produces [0, CI2].
1939 Upper = CI2->getValue() + 1;
1940 } else if (match(LHS, m_UDiv(m_Value(), m_ConstantInt(CI2)))) {
1941 // 'udiv x, CI2' produces [0, UINT_MAX / CI2].
1942 APInt NegOne = APInt::getAllOnesValue(Width);
1944 Upper = NegOne.udiv(CI2->getValue()) + 1;
1945 } else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) {
1946 // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2].
1947 APInt IntMin = APInt::getSignedMinValue(Width);
1948 APInt IntMax = APInt::getSignedMaxValue(Width);
1949 APInt Val = CI2->getValue().abs();
1950 if (!Val.isMinValue()) {
1951 Lower = IntMin.sdiv(Val);
1952 Upper = IntMax.sdiv(Val) + 1;
1954 } else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) {
1955 // 'lshr x, CI2' produces [0, UINT_MAX >> CI2].
1956 APInt NegOne = APInt::getAllOnesValue(Width);
1957 if (CI2->getValue().ult(Width))
1958 Upper = NegOne.lshr(CI2->getValue()) + 1;
1959 } else if (match(LHS, m_AShr(m_Value(), m_ConstantInt(CI2)))) {
1960 // 'ashr x, CI2' produces [INT_MIN >> CI2, INT_MAX >> CI2].
1961 APInt IntMin = APInt::getSignedMinValue(Width);
1962 APInt IntMax = APInt::getSignedMaxValue(Width);
1963 if (CI2->getValue().ult(Width)) {
1964 Lower = IntMin.ashr(CI2->getValue());
1965 Upper = IntMax.ashr(CI2->getValue()) + 1;
1967 } else if (match(LHS, m_Or(m_Value(), m_ConstantInt(CI2)))) {
1968 // 'or x, CI2' produces [CI2, UINT_MAX].
1969 Lower = CI2->getValue();
1970 } else if (match(LHS, m_And(m_Value(), m_ConstantInt(CI2)))) {
1971 // 'and x, CI2' produces [0, CI2].
1972 Upper = CI2->getValue() + 1;
1974 if (Lower != Upper) {
1975 ConstantRange LHS_CR = ConstantRange(Lower, Upper);
1976 if (RHS_CR.contains(LHS_CR))
1977 return ConstantInt::getTrue(RHS->getContext());
1978 if (RHS_CR.inverse().contains(LHS_CR))
1979 return ConstantInt::getFalse(RHS->getContext());
1983 // Compare of cast, for example (zext X) != 0 -> X != 0
1984 if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
1985 Instruction *LI = cast<CastInst>(LHS);
1986 Value *SrcOp = LI->getOperand(0);
1987 Type *SrcTy = SrcOp->getType();
1988 Type *DstTy = LI->getType();
1990 // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
1991 // if the integer type is the same size as the pointer type.
1992 if (MaxRecurse && Q.TD && isa<PtrToIntInst>(LI) &&
1993 Q.TD->getPointerSizeInBits() == DstTy->getPrimitiveSizeInBits()) {
1994 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
1995 // Transfer the cast to the constant.
1996 if (Value *V = SimplifyICmpInst(Pred, SrcOp,
1997 ConstantExpr::getIntToPtr(RHSC, SrcTy),
2000 } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
2001 if (RI->getOperand(0)->getType() == SrcTy)
2002 // Compare without the cast.
2003 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2009 if (isa<ZExtInst>(LHS)) {
2010 // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
2012 if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
2013 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2014 // Compare X and Y. Note that signed predicates become unsigned.
2015 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
2016 SrcOp, RI->getOperand(0), Q,
2020 // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
2021 // too. If not, then try to deduce the result of the comparison.
2022 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2023 // Compute the constant that would happen if we truncated to SrcTy then
2024 // reextended to DstTy.
2025 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2026 Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
2028 // If the re-extended constant didn't change then this is effectively
2029 // also a case of comparing two zero-extended values.
2030 if (RExt == CI && MaxRecurse)
2031 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
2032 SrcOp, Trunc, Q, MaxRecurse-1))
2035 // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
2036 // there. Use this to work out the result of the comparison.
2039 default: llvm_unreachable("Unknown ICmp predicate!");
2041 case ICmpInst::ICMP_EQ:
2042 case ICmpInst::ICMP_UGT:
2043 case ICmpInst::ICMP_UGE:
2044 return ConstantInt::getFalse(CI->getContext());
2046 case ICmpInst::ICMP_NE:
2047 case ICmpInst::ICMP_ULT:
2048 case ICmpInst::ICMP_ULE:
2049 return ConstantInt::getTrue(CI->getContext());
2051 // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
2052 // is non-negative then LHS <s RHS.
2053 case ICmpInst::ICMP_SGT:
2054 case ICmpInst::ICMP_SGE:
2055 return CI->getValue().isNegative() ?
2056 ConstantInt::getTrue(CI->getContext()) :
2057 ConstantInt::getFalse(CI->getContext());
2059 case ICmpInst::ICMP_SLT:
2060 case ICmpInst::ICMP_SLE:
2061 return CI->getValue().isNegative() ?
2062 ConstantInt::getFalse(CI->getContext()) :
2063 ConstantInt::getTrue(CI->getContext());
2069 if (isa<SExtInst>(LHS)) {
2070 // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
2072 if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
2073 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
2074 // Compare X and Y. Note that the predicate does not change.
2075 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
2079 // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
2080 // too. If not, then try to deduce the result of the comparison.
2081 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
2082 // Compute the constant that would happen if we truncated to SrcTy then
2083 // reextended to DstTy.
2084 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
2085 Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
2087 // If the re-extended constant didn't change then this is effectively
2088 // also a case of comparing two sign-extended values.
2089 if (RExt == CI && MaxRecurse)
2090 if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
2093 // Otherwise the upper bits of LHS are all equal, while RHS has varying
2094 // bits there. Use this to work out the result of the comparison.
2097 default: llvm_unreachable("Unknown ICmp predicate!");
2098 case ICmpInst::ICMP_EQ:
2099 return ConstantInt::getFalse(CI->getContext());
2100 case ICmpInst::ICMP_NE:
2101 return ConstantInt::getTrue(CI->getContext());
2103 // If RHS is non-negative then LHS <s RHS. If RHS is negative then
2105 case ICmpInst::ICMP_SGT:
2106 case ICmpInst::ICMP_SGE:
2107 return CI->getValue().isNegative() ?
2108 ConstantInt::getTrue(CI->getContext()) :
2109 ConstantInt::getFalse(CI->getContext());
2110 case ICmpInst::ICMP_SLT:
2111 case ICmpInst::ICMP_SLE:
2112 return CI->getValue().isNegative() ?
2113 ConstantInt::getFalse(CI->getContext()) :
2114 ConstantInt::getTrue(CI->getContext());
2116 // If LHS is non-negative then LHS <u RHS. If LHS is negative then
2118 case ICmpInst::ICMP_UGT:
2119 case ICmpInst::ICMP_UGE:
2120 // Comparison is true iff the LHS <s 0.
2122 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
2123 Constant::getNullValue(SrcTy),
2127 case ICmpInst::ICMP_ULT:
2128 case ICmpInst::ICMP_ULE:
2129 // Comparison is true iff the LHS >=s 0.
2131 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
2132 Constant::getNullValue(SrcTy),
2142 // Special logic for binary operators.
2143 BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
2144 BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
2145 if (MaxRecurse && (LBO || RBO)) {
2146 // Analyze the case when either LHS or RHS is an add instruction.
2147 Value *A = 0, *B = 0, *C = 0, *D = 0;
2148 // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
2149 bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
2150 if (LBO && LBO->getOpcode() == Instruction::Add) {
2151 A = LBO->getOperand(0); B = LBO->getOperand(1);
2152 NoLHSWrapProblem = ICmpInst::isEquality(Pred) ||
2153 (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
2154 (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
2156 if (RBO && RBO->getOpcode() == Instruction::Add) {
2157 C = RBO->getOperand(0); D = RBO->getOperand(1);
2158 NoRHSWrapProblem = ICmpInst::isEquality(Pred) ||
2159 (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
2160 (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
2163 // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
2164 if ((A == RHS || B == RHS) && NoLHSWrapProblem)
2165 if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
2166 Constant::getNullValue(RHS->getType()),
2170 // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
2171 if ((C == LHS || D == LHS) && NoRHSWrapProblem)
2172 if (Value *V = SimplifyICmpInst(Pred,
2173 Constant::getNullValue(LHS->getType()),
2174 C == LHS ? D : C, Q, MaxRecurse-1))
2177 // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
2178 if (A && C && (A == C || A == D || B == C || B == D) &&
2179 NoLHSWrapProblem && NoRHSWrapProblem) {
2180 // Determine Y and Z in the form icmp (X+Y), (X+Z).
2183 // C + B == C + D -> B == D
2186 } else if (A == D) {
2187 // D + B == C + D -> B == C
2190 } else if (B == C) {
2191 // A + C == C + D -> A == D
2196 // A + D == C + D -> A == C
2200 if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse-1))
2205 if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
2206 bool KnownNonNegative, KnownNegative;
2210 case ICmpInst::ICMP_SGT:
2211 case ICmpInst::ICMP_SGE:
2212 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.TD);
2213 if (!KnownNonNegative)
2216 case ICmpInst::ICMP_EQ:
2217 case ICmpInst::ICMP_UGT:
2218 case ICmpInst::ICMP_UGE:
2219 return getFalse(ITy);
2220 case ICmpInst::ICMP_SLT:
2221 case ICmpInst::ICMP_SLE:
2222 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.TD);
2223 if (!KnownNonNegative)
2226 case ICmpInst::ICMP_NE:
2227 case ICmpInst::ICMP_ULT:
2228 case ICmpInst::ICMP_ULE:
2229 return getTrue(ITy);
2232 if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
2233 bool KnownNonNegative, KnownNegative;
2237 case ICmpInst::ICMP_SGT:
2238 case ICmpInst::ICMP_SGE:
2239 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.TD);
2240 if (!KnownNonNegative)
2243 case ICmpInst::ICMP_NE:
2244 case ICmpInst::ICMP_UGT:
2245 case ICmpInst::ICMP_UGE:
2246 return getTrue(ITy);
2247 case ICmpInst::ICMP_SLT:
2248 case ICmpInst::ICMP_SLE:
2249 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.TD);
2250 if (!KnownNonNegative)
2253 case ICmpInst::ICMP_EQ:
2254 case ICmpInst::ICMP_ULT:
2255 case ICmpInst::ICMP_ULE:
2256 return getFalse(ITy);
2261 if (LBO && match(LBO, m_UDiv(m_Specific(RHS), m_Value()))) {
2262 // icmp pred (X /u Y), X
2263 if (Pred == ICmpInst::ICMP_UGT)
2264 return getFalse(ITy);
2265 if (Pred == ICmpInst::ICMP_ULE)
2266 return getTrue(ITy);
2269 if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
2270 LBO->getOperand(1) == RBO->getOperand(1)) {
2271 switch (LBO->getOpcode()) {
2273 case Instruction::UDiv:
2274 case Instruction::LShr:
2275 if (ICmpInst::isSigned(Pred))
2278 case Instruction::SDiv:
2279 case Instruction::AShr:
2280 if (!LBO->isExact() || !RBO->isExact())
2282 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2283 RBO->getOperand(0), Q, MaxRecurse-1))
2286 case Instruction::Shl: {
2287 bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
2288 bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
2291 if (!NSW && ICmpInst::isSigned(Pred))
2293 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2294 RBO->getOperand(0), Q, MaxRecurse-1))
2301 // Simplify comparisons involving max/min.
2303 CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE;
2304 CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
2306 // Signed variants on "max(a,b)>=a -> true".
2307 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2308 if (A != RHS) std::swap(A, B); // smax(A, B) pred A.
2309 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2310 // We analyze this as smax(A, B) pred A.
2312 } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
2313 (A == LHS || B == LHS)) {
2314 if (A != LHS) std::swap(A, B); // A pred smax(A, B).
2315 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2316 // We analyze this as smax(A, B) swapped-pred A.
2317 P = CmpInst::getSwappedPredicate(Pred);
2318 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2319 (A == RHS || B == RHS)) {
2320 if (A != RHS) std::swap(A, B); // smin(A, B) pred A.
2321 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2322 // We analyze this as smax(-A, -B) swapped-pred -A.
2323 // Note that we do not need to actually form -A or -B thanks to EqP.
2324 P = CmpInst::getSwappedPredicate(Pred);
2325 } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
2326 (A == LHS || B == LHS)) {
2327 if (A != LHS) std::swap(A, B); // A pred smin(A, B).
2328 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2329 // We analyze this as smax(-A, -B) pred -A.
2330 // Note that we do not need to actually form -A or -B thanks to EqP.
2333 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2334 // Cases correspond to "max(A, B) p A".
2338 case CmpInst::ICMP_EQ:
2339 case CmpInst::ICMP_SLE:
2340 // Equivalent to "A EqP B". This may be the same as the condition tested
2341 // in the max/min; if so, we can just return that.
2342 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2344 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2346 // Otherwise, see if "A EqP B" simplifies.
2348 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2351 case CmpInst::ICMP_NE:
2352 case CmpInst::ICMP_SGT: {
2353 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2354 // Equivalent to "A InvEqP B". This may be the same as the condition
2355 // tested in the max/min; if so, we can just return that.
2356 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2358 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2360 // Otherwise, see if "A InvEqP B" simplifies.
2362 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2366 case CmpInst::ICMP_SGE:
2368 return getTrue(ITy);
2369 case CmpInst::ICMP_SLT:
2371 return getFalse(ITy);
2375 // Unsigned variants on "max(a,b)>=a -> true".
2376 P = CmpInst::BAD_ICMP_PREDICATE;
2377 if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2378 if (A != RHS) std::swap(A, B); // umax(A, B) pred A.
2379 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2380 // We analyze this as umax(A, B) pred A.
2382 } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
2383 (A == LHS || B == LHS)) {
2384 if (A != LHS) std::swap(A, B); // A pred umax(A, B).
2385 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2386 // We analyze this as umax(A, B) swapped-pred A.
2387 P = CmpInst::getSwappedPredicate(Pred);
2388 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2389 (A == RHS || B == RHS)) {
2390 if (A != RHS) std::swap(A, B); // umin(A, B) pred A.
2391 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2392 // We analyze this as umax(-A, -B) swapped-pred -A.
2393 // Note that we do not need to actually form -A or -B thanks to EqP.
2394 P = CmpInst::getSwappedPredicate(Pred);
2395 } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
2396 (A == LHS || B == LHS)) {
2397 if (A != LHS) std::swap(A, B); // A pred umin(A, B).
2398 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2399 // We analyze this as umax(-A, -B) pred -A.
2400 // Note that we do not need to actually form -A or -B thanks to EqP.
2403 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2404 // Cases correspond to "max(A, B) p A".
2408 case CmpInst::ICMP_EQ:
2409 case CmpInst::ICMP_ULE:
2410 // Equivalent to "A EqP B". This may be the same as the condition tested
2411 // in the max/min; if so, we can just return that.
2412 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2414 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2416 // Otherwise, see if "A EqP B" simplifies.
2418 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2421 case CmpInst::ICMP_NE:
2422 case CmpInst::ICMP_UGT: {
2423 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2424 // Equivalent to "A InvEqP B". This may be the same as the condition
2425 // tested in the max/min; if so, we can just return that.
2426 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2428 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2430 // Otherwise, see if "A InvEqP B" simplifies.
2432 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2436 case CmpInst::ICMP_UGE:
2438 return getTrue(ITy);
2439 case CmpInst::ICMP_ULT:
2441 return getFalse(ITy);
2445 // Variants on "max(x,y) >= min(x,z)".
2447 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
2448 match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
2449 (A == C || A == D || B == C || B == D)) {
2450 // max(x, ?) pred min(x, ?).
2451 if (Pred == CmpInst::ICMP_SGE)
2453 return getTrue(ITy);
2454 if (Pred == CmpInst::ICMP_SLT)
2456 return getFalse(ITy);
2457 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2458 match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
2459 (A == C || A == D || B == C || B == D)) {
2460 // min(x, ?) pred max(x, ?).
2461 if (Pred == CmpInst::ICMP_SLE)
2463 return getTrue(ITy);
2464 if (Pred == CmpInst::ICMP_SGT)
2466 return getFalse(ITy);
2467 } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
2468 match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
2469 (A == C || A == D || B == C || B == D)) {
2470 // max(x, ?) pred min(x, ?).
2471 if (Pred == CmpInst::ICMP_UGE)
2473 return getTrue(ITy);
2474 if (Pred == CmpInst::ICMP_ULT)
2476 return getFalse(ITy);
2477 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2478 match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
2479 (A == C || A == D || B == C || B == D)) {
2480 // min(x, ?) pred max(x, ?).
2481 if (Pred == CmpInst::ICMP_ULE)
2483 return getTrue(ITy);
2484 if (Pred == CmpInst::ICMP_UGT)
2486 return getFalse(ITy);
2489 // Simplify comparisons of related pointers using a powerful, recursive
2490 // GEP-walk when we have target data available..
2491 if (LHS->getType()->isPointerTy())
2492 if (Constant *C = computePointerICmp(Q.TD, Q.TLI, Pred, LHS, RHS))
2495 if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
2496 if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
2497 if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
2498 GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
2499 (ICmpInst::isEquality(Pred) ||
2500 (GLHS->isInBounds() && GRHS->isInBounds() &&
2501 Pred == ICmpInst::getSignedPredicate(Pred)))) {
2502 // The bases are equal and the indices are constant. Build a constant
2503 // expression GEP with the same indices and a null base pointer to see
2504 // what constant folding can make out of it.
2505 Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
2506 SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
2507 Constant *NewLHS = ConstantExpr::getGetElementPtr(Null, IndicesLHS);
2509 SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
2510 Constant *NewRHS = ConstantExpr::getGetElementPtr(Null, IndicesRHS);
2511 return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
2516 // If the comparison is with the result of a select instruction, check whether
2517 // comparing with either branch of the select always yields the same value.
2518 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2519 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
2522 // If the comparison is with the result of a phi instruction, check whether
2523 // doing the compare with each incoming phi value yields a common result.
2524 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2525 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
2531 Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2532 const DataLayout *TD,
2533 const TargetLibraryInfo *TLI,
2534 const DominatorTree *DT) {
2535 return ::SimplifyICmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
2539 /// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can
2540 /// fold the result. If not, this returns null.
2541 static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2542 const Query &Q, unsigned MaxRecurse) {
2543 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
2544 assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
2546 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
2547 if (Constant *CRHS = dyn_cast<Constant>(RHS))
2548 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.TD, Q.TLI);
2550 // If we have a constant, make sure it is on the RHS.
2551 std::swap(LHS, RHS);
2552 Pred = CmpInst::getSwappedPredicate(Pred);
2555 // Fold trivial predicates.
2556 if (Pred == FCmpInst::FCMP_FALSE)
2557 return ConstantInt::get(GetCompareTy(LHS), 0);
2558 if (Pred == FCmpInst::FCMP_TRUE)
2559 return ConstantInt::get(GetCompareTy(LHS), 1);
2561 if (isa<UndefValue>(RHS)) // fcmp pred X, undef -> undef
2562 return UndefValue::get(GetCompareTy(LHS));
2564 // fcmp x,x -> true/false. Not all compares are foldable.
2566 if (CmpInst::isTrueWhenEqual(Pred))
2567 return ConstantInt::get(GetCompareTy(LHS), 1);
2568 if (CmpInst::isFalseWhenEqual(Pred))
2569 return ConstantInt::get(GetCompareTy(LHS), 0);
2572 // Handle fcmp with constant RHS
2573 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
2574 // If the constant is a nan, see if we can fold the comparison based on it.
2575 if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHSC)) {
2576 if (CFP->getValueAPF().isNaN()) {
2577 if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo"
2578 return ConstantInt::getFalse(CFP->getContext());
2579 assert(FCmpInst::isUnordered(Pred) &&
2580 "Comparison must be either ordered or unordered!");
2581 // True if unordered.
2582 return ConstantInt::getTrue(CFP->getContext());
2584 // Check whether the constant is an infinity.
2585 if (CFP->getValueAPF().isInfinity()) {
2586 if (CFP->getValueAPF().isNegative()) {
2588 case FCmpInst::FCMP_OLT:
2589 // No value is ordered and less than negative infinity.
2590 return ConstantInt::getFalse(CFP->getContext());
2591 case FCmpInst::FCMP_UGE:
2592 // All values are unordered with or at least negative infinity.
2593 return ConstantInt::getTrue(CFP->getContext());
2599 case FCmpInst::FCMP_OGT:
2600 // No value is ordered and greater than infinity.
2601 return ConstantInt::getFalse(CFP->getContext());
2602 case FCmpInst::FCMP_ULE:
2603 // All values are unordered with and at most infinity.
2604 return ConstantInt::getTrue(CFP->getContext());
2613 // If the comparison is with the result of a select instruction, check whether
2614 // comparing with either branch of the select always yields the same value.
2615 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2616 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
2619 // If the comparison is with the result of a phi instruction, check whether
2620 // doing the compare with each incoming phi value yields a common result.
2621 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2622 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
2628 Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2629 const DataLayout *TD,
2630 const TargetLibraryInfo *TLI,
2631 const DominatorTree *DT) {
2632 return ::SimplifyFCmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
2636 /// SimplifySelectInst - Given operands for a SelectInst, see if we can fold
2637 /// the result. If not, this returns null.
2638 static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal,
2639 Value *FalseVal, const Query &Q,
2640 unsigned MaxRecurse) {
2641 // select true, X, Y -> X
2642 // select false, X, Y -> Y
2643 if (ConstantInt *CB = dyn_cast<ConstantInt>(CondVal))
2644 return CB->getZExtValue() ? TrueVal : FalseVal;
2646 // select C, X, X -> X
2647 if (TrueVal == FalseVal)
2650 if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y
2651 if (isa<Constant>(TrueVal))
2655 if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X
2657 if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
2663 Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
2664 const DataLayout *TD,
2665 const TargetLibraryInfo *TLI,
2666 const DominatorTree *DT) {
2667 return ::SimplifySelectInst(Cond, TrueVal, FalseVal, Query (TD, TLI, DT),
2671 /// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
2672 /// fold the result. If not, this returns null.
2673 static Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const Query &Q, unsigned) {
2674 // The type of the GEP pointer operand.
2675 PointerType *PtrTy = dyn_cast<PointerType>(Ops[0]->getType());
2676 // The GEP pointer operand is not a pointer, it's a vector of pointers.
2680 // getelementptr P -> P.
2681 if (Ops.size() == 1)
2684 if (isa<UndefValue>(Ops[0])) {
2685 // Compute the (pointer) type returned by the GEP instruction.
2686 Type *LastType = GetElementPtrInst::getIndexedType(PtrTy, Ops.slice(1));
2687 Type *GEPTy = PointerType::get(LastType, PtrTy->getAddressSpace());
2688 return UndefValue::get(GEPTy);
2691 if (Ops.size() == 2) {
2692 // getelementptr P, 0 -> P.
2693 if (ConstantInt *C = dyn_cast<ConstantInt>(Ops[1]))
2696 // getelementptr P, N -> P if P points to a type of zero size.
2698 Type *Ty = PtrTy->getElementType();
2699 if (Ty->isSized() && Q.TD->getTypeAllocSize(Ty) == 0)
2704 // Check to see if this is constant foldable.
2705 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
2706 if (!isa<Constant>(Ops[i]))
2709 return ConstantExpr::getGetElementPtr(cast<Constant>(Ops[0]), Ops.slice(1));
2712 Value *llvm::SimplifyGEPInst(ArrayRef<Value *> Ops, const DataLayout *TD,
2713 const TargetLibraryInfo *TLI,
2714 const DominatorTree *DT) {
2715 return ::SimplifyGEPInst(Ops, Query (TD, TLI, DT), RecursionLimit);
2718 /// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we
2719 /// can fold the result. If not, this returns null.
2720 static Value *SimplifyInsertValueInst(Value *Agg, Value *Val,
2721 ArrayRef<unsigned> Idxs, const Query &Q,
2723 if (Constant *CAgg = dyn_cast<Constant>(Agg))
2724 if (Constant *CVal = dyn_cast<Constant>(Val))
2725 return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
2727 // insertvalue x, undef, n -> x
2728 if (match(Val, m_Undef()))
2731 // insertvalue x, (extractvalue y, n), n
2732 if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
2733 if (EV->getAggregateOperand()->getType() == Agg->getType() &&
2734 EV->getIndices() == Idxs) {
2735 // insertvalue undef, (extractvalue y, n), n -> y
2736 if (match(Agg, m_Undef()))
2737 return EV->getAggregateOperand();
2739 // insertvalue y, (extractvalue y, n), n -> y
2740 if (Agg == EV->getAggregateOperand())
2747 Value *llvm::SimplifyInsertValueInst(Value *Agg, Value *Val,
2748 ArrayRef<unsigned> Idxs,
2749 const DataLayout *TD,
2750 const TargetLibraryInfo *TLI,
2751 const DominatorTree *DT) {
2752 return ::SimplifyInsertValueInst(Agg, Val, Idxs, Query (TD, TLI, DT),
2756 /// SimplifyPHINode - See if we can fold the given phi. If not, returns null.
2757 static Value *SimplifyPHINode(PHINode *PN, const Query &Q) {
2758 // If all of the PHI's incoming values are the same then replace the PHI node
2759 // with the common value.
2760 Value *CommonValue = 0;
2761 bool HasUndefInput = false;
2762 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
2763 Value *Incoming = PN->getIncomingValue(i);
2764 // If the incoming value is the phi node itself, it can safely be skipped.
2765 if (Incoming == PN) continue;
2766 if (isa<UndefValue>(Incoming)) {
2767 // Remember that we saw an undef value, but otherwise ignore them.
2768 HasUndefInput = true;
2771 if (CommonValue && Incoming != CommonValue)
2772 return 0; // Not the same, bail out.
2773 CommonValue = Incoming;
2776 // If CommonValue is null then all of the incoming values were either undef or
2777 // equal to the phi node itself.
2779 return UndefValue::get(PN->getType());
2781 // If we have a PHI node like phi(X, undef, X), where X is defined by some
2782 // instruction, we cannot return X as the result of the PHI node unless it
2783 // dominates the PHI block.
2785 return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : 0;
2790 static Value *SimplifyTruncInst(Value *Op, Type *Ty, const Query &Q, unsigned) {
2791 if (Constant *C = dyn_cast<Constant>(Op))
2792 return ConstantFoldInstOperands(Instruction::Trunc, Ty, C, Q.TD, Q.TLI);
2797 Value *llvm::SimplifyTruncInst(Value *Op, Type *Ty, const DataLayout *TD,
2798 const TargetLibraryInfo *TLI,
2799 const DominatorTree *DT) {
2800 return ::SimplifyTruncInst(Op, Ty, Query (TD, TLI, DT), RecursionLimit);
2803 //=== Helper functions for higher up the class hierarchy.
2805 /// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
2806 /// fold the result. If not, this returns null.
2807 static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
2808 const Query &Q, unsigned MaxRecurse) {
2810 case Instruction::Add:
2811 return SimplifyAddInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2813 case Instruction::FAdd:
2814 return SimplifyFAddInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
2816 case Instruction::Sub:
2817 return SimplifySubInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2819 case Instruction::FSub:
2820 return SimplifyFSubInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
2822 case Instruction::Mul: return SimplifyMulInst (LHS, RHS, Q, MaxRecurse);
2823 case Instruction::FMul:
2824 return SimplifyFMulInst (LHS, RHS, FastMathFlags(), Q, MaxRecurse);
2825 case Instruction::SDiv: return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
2826 case Instruction::UDiv: return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
2827 case Instruction::FDiv: return SimplifyFDivInst(LHS, RHS, Q, MaxRecurse);
2828 case Instruction::SRem: return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
2829 case Instruction::URem: return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
2830 case Instruction::FRem: return SimplifyFRemInst(LHS, RHS, Q, MaxRecurse);
2831 case Instruction::Shl:
2832 return SimplifyShlInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2834 case Instruction::LShr:
2835 return SimplifyLShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
2836 case Instruction::AShr:
2837 return SimplifyAShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
2838 case Instruction::And: return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
2839 case Instruction::Or: return SimplifyOrInst (LHS, RHS, Q, MaxRecurse);
2840 case Instruction::Xor: return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
2842 if (Constant *CLHS = dyn_cast<Constant>(LHS))
2843 if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
2844 Constant *COps[] = {CLHS, CRHS};
2845 return ConstantFoldInstOperands(Opcode, LHS->getType(), COps, Q.TD,
2849 // If the operation is associative, try some generic simplifications.
2850 if (Instruction::isAssociative(Opcode))
2851 if (Value *V = SimplifyAssociativeBinOp(Opcode, LHS, RHS, Q, MaxRecurse))
2854 // If the operation is with the result of a select instruction check whether
2855 // operating on either branch of the select always yields the same value.
2856 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2857 if (Value *V = ThreadBinOpOverSelect(Opcode, LHS, RHS, Q, MaxRecurse))
2860 // If the operation is with the result of a phi instruction, check whether
2861 // operating on all incoming values of the phi always yields the same value.
2862 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2863 if (Value *V = ThreadBinOpOverPHI(Opcode, LHS, RHS, Q, MaxRecurse))
2870 Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
2871 const DataLayout *TD, const TargetLibraryInfo *TLI,
2872 const DominatorTree *DT) {
2873 return ::SimplifyBinOp(Opcode, LHS, RHS, Query (TD, TLI, DT), RecursionLimit);
2876 /// SimplifyCmpInst - Given operands for a CmpInst, see if we can
2877 /// fold the result.
2878 static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2879 const Query &Q, unsigned MaxRecurse) {
2880 if (CmpInst::isIntPredicate((CmpInst::Predicate)Predicate))
2881 return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
2882 return SimplifyFCmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
2885 Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2886 const DataLayout *TD, const TargetLibraryInfo *TLI,
2887 const DominatorTree *DT) {
2888 return ::SimplifyCmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
2892 template <typename IterTy>
2893 static Value *SimplifyCall(Value *V, IterTy ArgBegin, IterTy ArgEnd,
2894 const Query &Q, unsigned MaxRecurse) {
2895 Type *Ty = V->getType();
2896 if (PointerType *PTy = dyn_cast<PointerType>(Ty))
2897 Ty = PTy->getElementType();
2898 FunctionType *FTy = cast<FunctionType>(Ty);
2900 // call undef -> undef
2901 if (isa<UndefValue>(V))
2902 return UndefValue::get(FTy->getReturnType());
2904 Function *F = dyn_cast<Function>(V);
2908 if (!canConstantFoldCallTo(F))
2911 SmallVector<Constant *, 4> ConstantArgs;
2912 ConstantArgs.reserve(ArgEnd - ArgBegin);
2913 for (IterTy I = ArgBegin, E = ArgEnd; I != E; ++I) {
2914 Constant *C = dyn_cast<Constant>(*I);
2917 ConstantArgs.push_back(C);
2920 return ConstantFoldCall(F, ConstantArgs, Q.TLI);
2923 Value *llvm::SimplifyCall(Value *V, User::op_iterator ArgBegin,
2924 User::op_iterator ArgEnd, const DataLayout *TD,
2925 const TargetLibraryInfo *TLI,
2926 const DominatorTree *DT) {
2927 return ::SimplifyCall(V, ArgBegin, ArgEnd, Query(TD, TLI, DT),
2931 Value *llvm::SimplifyCall(Value *V, ArrayRef<Value *> Args,
2932 const DataLayout *TD, const TargetLibraryInfo *TLI,
2933 const DominatorTree *DT) {
2934 return ::SimplifyCall(V, Args.begin(), Args.end(), Query(TD, TLI, DT),
2938 /// SimplifyInstruction - See if we can compute a simplified version of this
2939 /// instruction. If not, this returns null.
2940 Value *llvm::SimplifyInstruction(Instruction *I, const DataLayout *TD,
2941 const TargetLibraryInfo *TLI,
2942 const DominatorTree *DT) {
2945 switch (I->getOpcode()) {
2947 Result = ConstantFoldInstruction(I, TD, TLI);
2949 case Instruction::FAdd:
2950 Result = SimplifyFAddInst(I->getOperand(0), I->getOperand(1),
2951 I->getFastMathFlags(), TD, TLI, DT);
2953 case Instruction::Add:
2954 Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
2955 cast<BinaryOperator>(I)->hasNoSignedWrap(),
2956 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
2959 case Instruction::FSub:
2960 Result = SimplifyFSubInst(I->getOperand(0), I->getOperand(1),
2961 I->getFastMathFlags(), TD, TLI, DT);
2963 case Instruction::Sub:
2964 Result = SimplifySubInst(I->getOperand(0), I->getOperand(1),
2965 cast<BinaryOperator>(I)->hasNoSignedWrap(),
2966 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
2969 case Instruction::FMul:
2970 Result = SimplifyFMulInst(I->getOperand(0), I->getOperand(1),
2971 I->getFastMathFlags(), TD, TLI, DT);
2973 case Instruction::Mul:
2974 Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2976 case Instruction::SDiv:
2977 Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2979 case Instruction::UDiv:
2980 Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2982 case Instruction::FDiv:
2983 Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2985 case Instruction::SRem:
2986 Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2988 case Instruction::URem:
2989 Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2991 case Instruction::FRem:
2992 Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2994 case Instruction::Shl:
2995 Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1),
2996 cast<BinaryOperator>(I)->hasNoSignedWrap(),
2997 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
3000 case Instruction::LShr:
3001 Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
3002 cast<BinaryOperator>(I)->isExact(),
3005 case Instruction::AShr:
3006 Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
3007 cast<BinaryOperator>(I)->isExact(),
3010 case Instruction::And:
3011 Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3013 case Instruction::Or:
3014 Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3016 case Instruction::Xor:
3017 Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3019 case Instruction::ICmp:
3020 Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
3021 I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3023 case Instruction::FCmp:
3024 Result = SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(),
3025 I->getOperand(0), I->getOperand(1), TD, TLI, DT);
3027 case Instruction::Select:
3028 Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
3029 I->getOperand(2), TD, TLI, DT);
3031 case Instruction::GetElementPtr: {
3032 SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end());
3033 Result = SimplifyGEPInst(Ops, TD, TLI, DT);
3036 case Instruction::InsertValue: {
3037 InsertValueInst *IV = cast<InsertValueInst>(I);
3038 Result = SimplifyInsertValueInst(IV->getAggregateOperand(),
3039 IV->getInsertedValueOperand(),
3040 IV->getIndices(), TD, TLI, DT);
3043 case Instruction::PHI:
3044 Result = SimplifyPHINode(cast<PHINode>(I), Query (TD, TLI, DT));
3046 case Instruction::Call: {
3047 CallSite CS(cast<CallInst>(I));
3048 Result = SimplifyCall(CS.getCalledValue(), CS.arg_begin(), CS.arg_end(),
3052 case Instruction::Trunc:
3053 Result = SimplifyTruncInst(I->getOperand(0), I->getType(), TD, TLI, DT);
3057 /// If called on unreachable code, the above logic may report that the
3058 /// instruction simplified to itself. Make life easier for users by
3059 /// detecting that case here, returning a safe value instead.
3060 return Result == I ? UndefValue::get(I->getType()) : Result;
3063 /// \brief Implementation of recursive simplification through an instructions
3066 /// This is the common implementation of the recursive simplification routines.
3067 /// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
3068 /// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
3069 /// instructions to process and attempt to simplify it using
3070 /// InstructionSimplify.
3072 /// This routine returns 'true' only when *it* simplifies something. The passed
3073 /// in simplified value does not count toward this.
3074 static bool replaceAndRecursivelySimplifyImpl(Instruction *I, Value *SimpleV,
3075 const DataLayout *TD,
3076 const TargetLibraryInfo *TLI,
3077 const DominatorTree *DT) {
3078 bool Simplified = false;
3079 SmallSetVector<Instruction *, 8> Worklist;
3081 // If we have an explicit value to collapse to, do that round of the
3082 // simplification loop by hand initially.
3084 for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE;
3087 Worklist.insert(cast<Instruction>(*UI));
3089 // Replace the instruction with its simplified value.
3090 I->replaceAllUsesWith(SimpleV);
3092 // Gracefully handle edge cases where the instruction is not wired into any
3095 I->eraseFromParent();
3100 // Note that we must test the size on each iteration, the worklist can grow.
3101 for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
3104 // See if this instruction simplifies.
3105 SimpleV = SimplifyInstruction(I, TD, TLI, DT);
3111 // Stash away all the uses of the old instruction so we can check them for
3112 // recursive simplifications after a RAUW. This is cheaper than checking all
3113 // uses of To on the recursive step in most cases.
3114 for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE;
3116 Worklist.insert(cast<Instruction>(*UI));
3118 // Replace the instruction with its simplified value.
3119 I->replaceAllUsesWith(SimpleV);
3121 // Gracefully handle edge cases where the instruction is not wired into any
3124 I->eraseFromParent();
3129 bool llvm::recursivelySimplifyInstruction(Instruction *I,
3130 const DataLayout *TD,
3131 const TargetLibraryInfo *TLI,
3132 const DominatorTree *DT) {
3133 return replaceAndRecursivelySimplifyImpl(I, 0, TD, TLI, DT);
3136 bool llvm::replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV,
3137 const DataLayout *TD,
3138 const TargetLibraryInfo *TLI,
3139 const DominatorTree *DT) {
3140 assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!");
3141 assert(SimpleV && "Must provide a simplified value.");
3142 return replaceAndRecursivelySimplifyImpl(I, SimpleV, TD, TLI, DT);