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/GlobalAlias.h"
22 #include "llvm/Operator.h"
23 #include "llvm/ADT/Statistic.h"
24 #include "llvm/Analysis/InstructionSimplify.h"
25 #include "llvm/Analysis/AliasAnalysis.h"
26 #include "llvm/Analysis/ConstantFolding.h"
27 #include "llvm/Analysis/Dominators.h"
28 #include "llvm/Analysis/ValueTracking.h"
29 #include "llvm/Support/ConstantRange.h"
30 #include "llvm/Support/GetElementPtrTypeIterator.h"
31 #include "llvm/Support/PatternMatch.h"
32 #include "llvm/Support/ValueHandle.h"
33 #include "llvm/Target/TargetData.h"
35 using namespace llvm::PatternMatch;
37 enum { RecursionLimit = 3 };
39 STATISTIC(NumExpand, "Number of expansions");
40 STATISTIC(NumFactor , "Number of factorizations");
41 STATISTIC(NumReassoc, "Number of reassociations");
45 const TargetLibraryInfo *TLI;
46 const DominatorTree *DT;
48 Query(const TargetData *td, const TargetLibraryInfo *tli,
49 const DominatorTree *dt) : TD(td), TLI(tli), DT(dt) {};
52 static Value *SimplifyAndInst(Value *, Value *, const Query &, unsigned);
53 static Value *SimplifyBinOp(unsigned, Value *, Value *, const Query &,
55 static Value *SimplifyCmpInst(unsigned, Value *, Value *, const Query &,
57 static Value *SimplifyOrInst(Value *, Value *, const Query &, unsigned);
58 static Value *SimplifyXorInst(Value *, Value *, const Query &, unsigned);
59 static Value *SimplifyTruncInst(Value *, Type *, const Query &, unsigned);
61 /// getFalse - For a boolean type, or a vector of boolean type, return false, or
62 /// a vector with every element false, as appropriate for the type.
63 static Constant *getFalse(Type *Ty) {
64 assert(Ty->getScalarType()->isIntegerTy(1) &&
65 "Expected i1 type or a vector of i1!");
66 return Constant::getNullValue(Ty);
69 /// getTrue - For a boolean type, or a vector of boolean type, return true, or
70 /// a vector with every element true, as appropriate for the type.
71 static Constant *getTrue(Type *Ty) {
72 assert(Ty->getScalarType()->isIntegerTy(1) &&
73 "Expected i1 type or a vector of i1!");
74 return Constant::getAllOnesValue(Ty);
77 /// isSameCompare - Is V equivalent to the comparison "LHS Pred RHS"?
78 static bool isSameCompare(Value *V, CmpInst::Predicate Pred, Value *LHS,
80 CmpInst *Cmp = dyn_cast<CmpInst>(V);
83 CmpInst::Predicate CPred = Cmp->getPredicate();
84 Value *CLHS = Cmp->getOperand(0), *CRHS = Cmp->getOperand(1);
85 if (CPred == Pred && CLHS == LHS && CRHS == RHS)
87 return CPred == CmpInst::getSwappedPredicate(Pred) && CLHS == RHS &&
91 /// ValueDominatesPHI - Does the given value dominate the specified phi node?
92 static bool ValueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
93 Instruction *I = dyn_cast<Instruction>(V);
95 // Arguments and constants dominate all instructions.
98 // If we have a DominatorTree then do a precise test.
100 if (!DT->isReachableFromEntry(P->getParent()))
102 if (!DT->isReachableFromEntry(I->getParent()))
104 return DT->dominates(I, P);
107 // Otherwise, if the instruction is in the entry block, and is not an invoke,
108 // then it obviously dominates all phi nodes.
109 if (I->getParent() == &I->getParent()->getParent()->getEntryBlock() &&
116 /// ExpandBinOp - Simplify "A op (B op' C)" by distributing op over op', turning
117 /// it into "(A op B) op' (A op C)". Here "op" is given by Opcode and "op'" is
118 /// given by OpcodeToExpand, while "A" corresponds to LHS and "B op' C" to RHS.
119 /// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)".
120 /// Returns the simplified value, or null if no simplification was performed.
121 static Value *ExpandBinOp(unsigned Opcode, Value *LHS, Value *RHS,
122 unsigned OpcToExpand, const Query &Q,
123 unsigned MaxRecurse) {
124 Instruction::BinaryOps OpcodeToExpand = (Instruction::BinaryOps)OpcToExpand;
125 // Recursion is always used, so bail out at once if we already hit the limit.
129 // Check whether the expression has the form "(A op' B) op C".
130 if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS))
131 if (Op0->getOpcode() == OpcodeToExpand) {
132 // It does! Try turning it into "(A op C) op' (B op C)".
133 Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS;
134 // Do "A op C" and "B op C" both simplify?
135 if (Value *L = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse))
136 if (Value *R = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
137 // They do! Return "L op' R" if it simplifies or is already available.
138 // If "L op' R" equals "A op' B" then "L op' R" is just the LHS.
139 if ((L == A && R == B) || (Instruction::isCommutative(OpcodeToExpand)
140 && L == B && R == A)) {
144 // Otherwise return "L op' R" if it simplifies.
145 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
152 // Check whether the expression has the form "A op (B op' C)".
153 if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS))
154 if (Op1->getOpcode() == OpcodeToExpand) {
155 // It does! Try turning it into "(A op B) op' (A op C)".
156 Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1);
157 // Do "A op B" and "A op C" both simplify?
158 if (Value *L = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse))
159 if (Value *R = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse)) {
160 // They do! Return "L op' R" if it simplifies or is already available.
161 // If "L op' R" equals "B op' C" then "L op' R" is just the RHS.
162 if ((L == B && R == C) || (Instruction::isCommutative(OpcodeToExpand)
163 && L == C && R == B)) {
167 // Otherwise return "L op' R" if it simplifies.
168 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
178 /// FactorizeBinOp - Simplify "LHS Opcode RHS" by factorizing out a common term
179 /// using the operation OpCodeToExtract. For example, when Opcode is Add and
180 /// OpCodeToExtract is Mul then this tries to turn "(A*B)+(A*C)" into "A*(B+C)".
181 /// Returns the simplified value, or null if no simplification was performed.
182 static Value *FactorizeBinOp(unsigned Opcode, Value *LHS, Value *RHS,
183 unsigned OpcToExtract, const Query &Q,
184 unsigned MaxRecurse) {
185 Instruction::BinaryOps OpcodeToExtract = (Instruction::BinaryOps)OpcToExtract;
186 // Recursion is always used, so bail out at once if we already hit the limit.
190 BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
191 BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
193 if (!Op0 || Op0->getOpcode() != OpcodeToExtract ||
194 !Op1 || Op1->getOpcode() != OpcodeToExtract)
197 // The expression has the form "(A op' B) op (C op' D)".
198 Value *A = Op0->getOperand(0), *B = Op0->getOperand(1);
199 Value *C = Op1->getOperand(0), *D = Op1->getOperand(1);
201 // Use left distributivity, i.e. "X op' (Y op Z) = (X op' Y) op (X op' Z)".
202 // Does the instruction have the form "(A op' B) op (A op' D)" or, in the
203 // commutative case, "(A op' B) op (C op' A)"?
204 if (A == C || (Instruction::isCommutative(OpcodeToExtract) && A == D)) {
205 Value *DD = A == C ? D : C;
206 // Form "A op' (B op DD)" if it simplifies completely.
207 // Does "B op DD" simplify?
208 if (Value *V = SimplifyBinOp(Opcode, B, DD, Q, MaxRecurse)) {
209 // It does! Return "A op' V" if it simplifies or is already available.
210 // If V equals B then "A op' V" is just the LHS. If V equals DD then
211 // "A op' V" is just the RHS.
212 if (V == B || V == DD) {
214 return V == B ? LHS : RHS;
216 // Otherwise return "A op' V" if it simplifies.
217 if (Value *W = SimplifyBinOp(OpcodeToExtract, A, V, Q, MaxRecurse)) {
224 // Use right distributivity, i.e. "(X op Y) op' Z = (X op' Z) op (Y op' Z)".
225 // Does the instruction have the form "(A op' B) op (C op' B)" or, in the
226 // commutative case, "(A op' B) op (B op' D)"?
227 if (B == D || (Instruction::isCommutative(OpcodeToExtract) && B == C)) {
228 Value *CC = B == D ? C : D;
229 // Form "(A op CC) op' B" if it simplifies completely..
230 // Does "A op CC" simplify?
231 if (Value *V = SimplifyBinOp(Opcode, A, CC, Q, MaxRecurse)) {
232 // It does! Return "V op' B" if it simplifies or is already available.
233 // If V equals A then "V op' B" is just the LHS. If V equals CC then
234 // "V op' B" is just the RHS.
235 if (V == A || V == CC) {
237 return V == A ? LHS : RHS;
239 // Otherwise return "V op' B" if it simplifies.
240 if (Value *W = SimplifyBinOp(OpcodeToExtract, V, B, Q, MaxRecurse)) {
250 /// SimplifyAssociativeBinOp - Generic simplifications for associative binary
251 /// operations. Returns the simpler value, or null if none was found.
252 static Value *SimplifyAssociativeBinOp(unsigned Opc, Value *LHS, Value *RHS,
253 const Query &Q, unsigned MaxRecurse) {
254 Instruction::BinaryOps Opcode = (Instruction::BinaryOps)Opc;
255 assert(Instruction::isAssociative(Opcode) && "Not an associative operation!");
257 // Recursion is always used, so bail out at once if we already hit the limit.
261 BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
262 BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
264 // Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely.
265 if (Op0 && Op0->getOpcode() == Opcode) {
266 Value *A = Op0->getOperand(0);
267 Value *B = Op0->getOperand(1);
270 // Does "B op C" simplify?
271 if (Value *V = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
272 // It does! Return "A op V" if it simplifies or is already available.
273 // If V equals B then "A op V" is just the LHS.
274 if (V == B) return LHS;
275 // Otherwise return "A op V" if it simplifies.
276 if (Value *W = SimplifyBinOp(Opcode, A, V, Q, MaxRecurse)) {
283 // Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely.
284 if (Op1 && Op1->getOpcode() == Opcode) {
286 Value *B = Op1->getOperand(0);
287 Value *C = Op1->getOperand(1);
289 // Does "A op B" simplify?
290 if (Value *V = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse)) {
291 // It does! Return "V op C" if it simplifies or is already available.
292 // If V equals B then "V op C" is just the RHS.
293 if (V == B) return RHS;
294 // Otherwise return "V op C" if it simplifies.
295 if (Value *W = SimplifyBinOp(Opcode, V, C, Q, MaxRecurse)) {
302 // The remaining transforms require commutativity as well as associativity.
303 if (!Instruction::isCommutative(Opcode))
306 // Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely.
307 if (Op0 && Op0->getOpcode() == Opcode) {
308 Value *A = Op0->getOperand(0);
309 Value *B = Op0->getOperand(1);
312 // Does "C op A" simplify?
313 if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
314 // It does! Return "V op B" if it simplifies or is already available.
315 // If V equals A then "V op B" is just the LHS.
316 if (V == A) return LHS;
317 // Otherwise return "V op B" if it simplifies.
318 if (Value *W = SimplifyBinOp(Opcode, V, B, Q, MaxRecurse)) {
325 // Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely.
326 if (Op1 && Op1->getOpcode() == Opcode) {
328 Value *B = Op1->getOperand(0);
329 Value *C = Op1->getOperand(1);
331 // Does "C op A" simplify?
332 if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
333 // It does! Return "B op V" if it simplifies or is already available.
334 // If V equals C then "B op V" is just the RHS.
335 if (V == C) return RHS;
336 // Otherwise return "B op V" if it simplifies.
337 if (Value *W = SimplifyBinOp(Opcode, B, V, Q, MaxRecurse)) {
347 /// ThreadBinOpOverSelect - In the case of a binary operation with a select
348 /// instruction as an operand, try to simplify the binop by seeing whether
349 /// evaluating it on both branches of the select results in the same value.
350 /// Returns the common value if so, otherwise returns null.
351 static Value *ThreadBinOpOverSelect(unsigned Opcode, Value *LHS, Value *RHS,
352 const Query &Q, unsigned MaxRecurse) {
353 // Recursion is always used, so bail out at once if we already hit the limit.
358 if (isa<SelectInst>(LHS)) {
359 SI = cast<SelectInst>(LHS);
361 assert(isa<SelectInst>(RHS) && "No select instruction operand!");
362 SI = cast<SelectInst>(RHS);
365 // Evaluate the BinOp on the true and false branches of the select.
369 TV = SimplifyBinOp(Opcode, SI->getTrueValue(), RHS, Q, MaxRecurse);
370 FV = SimplifyBinOp(Opcode, SI->getFalseValue(), RHS, Q, MaxRecurse);
372 TV = SimplifyBinOp(Opcode, LHS, SI->getTrueValue(), Q, MaxRecurse);
373 FV = SimplifyBinOp(Opcode, LHS, SI->getFalseValue(), Q, MaxRecurse);
376 // If they simplified to the same value, then return the common value.
377 // If they both failed to simplify then return null.
381 // If one branch simplified to undef, return the other one.
382 if (TV && isa<UndefValue>(TV))
384 if (FV && isa<UndefValue>(FV))
387 // If applying the operation did not change the true and false select values,
388 // then the result of the binop is the select itself.
389 if (TV == SI->getTrueValue() && FV == SI->getFalseValue())
392 // If one branch simplified and the other did not, and the simplified
393 // value is equal to the unsimplified one, return the simplified value.
394 // For example, select (cond, X, X & Z) & Z -> X & Z.
395 if ((FV && !TV) || (TV && !FV)) {
396 // Check that the simplified value has the form "X op Y" where "op" is the
397 // same as the original operation.
398 Instruction *Simplified = dyn_cast<Instruction>(FV ? FV : TV);
399 if (Simplified && Simplified->getOpcode() == Opcode) {
400 // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS".
401 // We already know that "op" is the same as for the simplified value. See
402 // if the operands match too. If so, return the simplified value.
403 Value *UnsimplifiedBranch = FV ? SI->getTrueValue() : SI->getFalseValue();
404 Value *UnsimplifiedLHS = SI == LHS ? UnsimplifiedBranch : LHS;
405 Value *UnsimplifiedRHS = SI == LHS ? RHS : UnsimplifiedBranch;
406 if (Simplified->getOperand(0) == UnsimplifiedLHS &&
407 Simplified->getOperand(1) == UnsimplifiedRHS)
409 if (Simplified->isCommutative() &&
410 Simplified->getOperand(1) == UnsimplifiedLHS &&
411 Simplified->getOperand(0) == UnsimplifiedRHS)
419 /// ThreadCmpOverSelect - In the case of a comparison with a select instruction,
420 /// try to simplify the comparison by seeing whether both branches of the select
421 /// result in the same value. Returns the common value if so, otherwise returns
423 static Value *ThreadCmpOverSelect(CmpInst::Predicate Pred, Value *LHS,
424 Value *RHS, const Query &Q,
425 unsigned MaxRecurse) {
426 // Recursion is always used, so bail out at once if we already hit the limit.
430 // Make sure the select is on the LHS.
431 if (!isa<SelectInst>(LHS)) {
433 Pred = CmpInst::getSwappedPredicate(Pred);
435 assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!");
436 SelectInst *SI = cast<SelectInst>(LHS);
437 Value *Cond = SI->getCondition();
438 Value *TV = SI->getTrueValue();
439 Value *FV = SI->getFalseValue();
441 // Now that we have "cmp select(Cond, TV, FV), RHS", analyse it.
442 // Does "cmp TV, RHS" simplify?
443 Value *TCmp = SimplifyCmpInst(Pred, TV, RHS, Q, MaxRecurse);
445 // It not only simplified, it simplified to the select condition. Replace
447 TCmp = getTrue(Cond->getType());
449 // It didn't simplify. However if "cmp TV, RHS" is equal to the select
450 // condition then we can replace it with 'true'. Otherwise give up.
451 if (!isSameCompare(Cond, Pred, TV, RHS))
453 TCmp = getTrue(Cond->getType());
456 // Does "cmp FV, RHS" simplify?
457 Value *FCmp = SimplifyCmpInst(Pred, FV, RHS, Q, MaxRecurse);
459 // It not only simplified, it simplified to the select condition. Replace
461 FCmp = getFalse(Cond->getType());
463 // It didn't simplify. However if "cmp FV, RHS" is equal to the select
464 // condition then we can replace it with 'false'. Otherwise give up.
465 if (!isSameCompare(Cond, Pred, FV, RHS))
467 FCmp = getFalse(Cond->getType());
470 // If both sides simplified to the same value, then use it as the result of
471 // the original comparison.
475 // The remaining cases only make sense if the select condition has the same
476 // type as the result of the comparison, so bail out if this is not so.
477 if (Cond->getType()->isVectorTy() != RHS->getType()->isVectorTy())
479 // If the false value simplified to false, then the result of the compare
480 // is equal to "Cond && TCmp". This also catches the case when the false
481 // value simplified to false and the true value to true, returning "Cond".
482 if (match(FCmp, m_Zero()))
483 if (Value *V = SimplifyAndInst(Cond, TCmp, Q, MaxRecurse))
485 // If the true value simplified to true, then the result of the compare
486 // is equal to "Cond || FCmp".
487 if (match(TCmp, m_One()))
488 if (Value *V = SimplifyOrInst(Cond, FCmp, Q, MaxRecurse))
490 // Finally, if the false value simplified to true and the true value to
491 // false, then the result of the compare is equal to "!Cond".
492 if (match(FCmp, m_One()) && match(TCmp, m_Zero()))
494 SimplifyXorInst(Cond, Constant::getAllOnesValue(Cond->getType()),
501 /// ThreadBinOpOverPHI - In the case of a binary operation with an operand that
502 /// is a PHI instruction, try to simplify the binop by seeing whether evaluating
503 /// it on the incoming phi values yields the same result for every value. If so
504 /// returns the common value, otherwise returns null.
505 static Value *ThreadBinOpOverPHI(unsigned Opcode, Value *LHS, Value *RHS,
506 const Query &Q, unsigned MaxRecurse) {
507 // Recursion is always used, so bail out at once if we already hit the limit.
512 if (isa<PHINode>(LHS)) {
513 PI = cast<PHINode>(LHS);
514 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
515 if (!ValueDominatesPHI(RHS, PI, Q.DT))
518 assert(isa<PHINode>(RHS) && "No PHI instruction operand!");
519 PI = cast<PHINode>(RHS);
520 // Bail out if LHS and the phi may be mutually interdependent due to a loop.
521 if (!ValueDominatesPHI(LHS, PI, Q.DT))
525 // Evaluate the BinOp on the incoming phi values.
526 Value *CommonValue = 0;
527 for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
528 Value *Incoming = PI->getIncomingValue(i);
529 // If the incoming value is the phi node itself, it can safely be skipped.
530 if (Incoming == PI) continue;
531 Value *V = PI == LHS ?
532 SimplifyBinOp(Opcode, Incoming, RHS, Q, MaxRecurse) :
533 SimplifyBinOp(Opcode, LHS, Incoming, Q, MaxRecurse);
534 // If the operation failed to simplify, or simplified to a different value
535 // to previously, then give up.
536 if (!V || (CommonValue && V != CommonValue))
544 /// ThreadCmpOverPHI - In the case of a comparison with a PHI instruction, try
545 /// try to simplify the comparison by seeing whether comparing with all of the
546 /// incoming phi values yields the same result every time. If so returns the
547 /// common result, otherwise returns null.
548 static Value *ThreadCmpOverPHI(CmpInst::Predicate Pred, Value *LHS, Value *RHS,
549 const Query &Q, unsigned MaxRecurse) {
550 // Recursion is always used, so bail out at once if we already hit the limit.
554 // Make sure the phi is on the LHS.
555 if (!isa<PHINode>(LHS)) {
557 Pred = CmpInst::getSwappedPredicate(Pred);
559 assert(isa<PHINode>(LHS) && "Not comparing with a phi instruction!");
560 PHINode *PI = cast<PHINode>(LHS);
562 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
563 if (!ValueDominatesPHI(RHS, PI, Q.DT))
566 // Evaluate the BinOp on the incoming phi values.
567 Value *CommonValue = 0;
568 for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
569 Value *Incoming = PI->getIncomingValue(i);
570 // If the incoming value is the phi node itself, it can safely be skipped.
571 if (Incoming == PI) continue;
572 Value *V = SimplifyCmpInst(Pred, Incoming, RHS, Q, MaxRecurse);
573 // If the operation failed to simplify, or simplified to a different value
574 // to previously, then give up.
575 if (!V || (CommonValue && V != CommonValue))
583 /// SimplifyAddInst - Given operands for an Add, see if we can
584 /// fold the result. If not, this returns null.
585 static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
586 const Query &Q, unsigned MaxRecurse) {
587 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
588 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
589 Constant *Ops[] = { CLHS, CRHS };
590 return ConstantFoldInstOperands(Instruction::Add, CLHS->getType(), Ops,
594 // Canonicalize the constant to the RHS.
598 // X + undef -> undef
599 if (match(Op1, m_Undef()))
603 if (match(Op1, m_Zero()))
610 if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) ||
611 match(Op0, m_Sub(m_Value(Y), m_Specific(Op1))))
614 // X + ~X -> -1 since ~X = -X-1
615 if (match(Op0, m_Not(m_Specific(Op1))) ||
616 match(Op1, m_Not(m_Specific(Op0))))
617 return Constant::getAllOnesValue(Op0->getType());
620 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
621 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
624 // Try some generic simplifications for associative operations.
625 if (Value *V = SimplifyAssociativeBinOp(Instruction::Add, Op0, Op1, Q,
629 // Mul distributes over Add. Try some generic simplifications based on this.
630 if (Value *V = FactorizeBinOp(Instruction::Add, Op0, Op1, Instruction::Mul,
634 // Threading Add over selects and phi nodes is pointless, so don't bother.
635 // Threading over the select in "A + select(cond, B, C)" means evaluating
636 // "A+B" and "A+C" and seeing if they are equal; but they are equal if and
637 // only if B and C are equal. If B and C are equal then (since we assume
638 // that operands have already been simplified) "select(cond, B, C)" should
639 // have been simplified to the common value of B and C already. Analysing
640 // "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly
641 // for threading over phi nodes.
646 Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
647 const TargetData *TD, const TargetLibraryInfo *TLI,
648 const DominatorTree *DT) {
649 return ::SimplifyAddInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT),
653 /// \brief Accumulate the constant integer offset a GEP represents.
655 /// Given a getelementptr instruction/constantexpr, accumulate the constant
656 /// offset from the base pointer into the provided APInt 'Offset'. Returns true
657 /// if the GEP has all-constant indices. Returns false if any non-constant
658 /// index is encountered leaving the 'Offset' in an undefined state. The
659 /// 'Offset' APInt must be the bitwidth of the target's pointer size.
660 static bool accumulateGEPOffset(const TargetData &TD, GEPOperator *GEP,
662 unsigned IntPtrWidth = TD.getPointerSizeInBits();
663 assert(IntPtrWidth == Offset.getBitWidth());
665 gep_type_iterator GTI = gep_type_begin(GEP);
666 for (User::op_iterator I = GEP->op_begin() + 1, E = GEP->op_end(); I != E;
668 ConstantInt *OpC = dyn_cast<ConstantInt>(*I);
669 if (!OpC) return false;
670 if (OpC->isZero()) continue;
672 // Handle a struct index, which adds its field offset to the pointer.
673 if (StructType *STy = dyn_cast<StructType>(*GTI)) {
674 unsigned ElementIdx = OpC->getZExtValue();
675 const StructLayout *SL = TD.getStructLayout(STy);
676 Offset += APInt(IntPtrWidth, SL->getElementOffset(ElementIdx));
680 APInt TypeSize(IntPtrWidth, TD.getTypeAllocSize(GTI.getIndexedType()));
681 Offset += OpC->getValue().sextOrTrunc(IntPtrWidth) * TypeSize;
686 /// \brief Compute the base pointer and cumulative constant offsets for V.
688 /// This strips all constant offsets off of V, leaving it the base pointer, and
689 /// accumulates the total constant offset applied in the returned constant. It
690 /// returns 0 if V is not a pointer, and returns the constant '0' if there are
691 /// no constant offsets applied.
692 static Constant *stripAndComputeConstantOffsets(const TargetData &TD,
694 if (!V->getType()->isPointerTy())
697 unsigned IntPtrWidth = TD.getPointerSizeInBits();
698 APInt Offset = APInt::getNullValue(IntPtrWidth);
700 // Even though we don't look through PHI nodes, we could be called on an
701 // instruction in an unreachable block, which may be on a cycle.
702 SmallPtrSet<Value *, 4> Visited;
705 if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
706 if (!accumulateGEPOffset(TD, GEP, Offset))
708 V = GEP->getPointerOperand();
709 } else if (Operator::getOpcode(V) == Instruction::BitCast) {
710 V = cast<Operator>(V)->getOperand(0);
711 } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
712 if (GA->mayBeOverridden())
714 V = GA->getAliasee();
718 assert(V->getType()->isPointerTy() && "Unexpected operand type!");
719 } while (Visited.insert(V));
721 Type *IntPtrTy = TD.getIntPtrType(V->getContext());
722 return ConstantInt::get(IntPtrTy, Offset);
725 /// \brief Compute the constant difference between two pointer values.
726 /// If the difference is not a constant, returns zero.
727 static Constant *computePointerDifference(const TargetData &TD,
728 Value *LHS, Value *RHS) {
729 Constant *LHSOffset = stripAndComputeConstantOffsets(TD, LHS);
732 Constant *RHSOffset = stripAndComputeConstantOffsets(TD, RHS);
736 // If LHS and RHS are not related via constant offsets to the same base
737 // value, there is nothing we can do here.
741 // Otherwise, the difference of LHS - RHS can be computed as:
743 // = (LHSOffset + Base) - (RHSOffset + Base)
744 // = LHSOffset - RHSOffset
745 return ConstantExpr::getSub(LHSOffset, RHSOffset);
748 /// SimplifySubInst - Given operands for a Sub, see if we can
749 /// fold the result. If not, this returns null.
750 static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
751 const Query &Q, unsigned MaxRecurse) {
752 if (Constant *CLHS = dyn_cast<Constant>(Op0))
753 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
754 Constant *Ops[] = { CLHS, CRHS };
755 return ConstantFoldInstOperands(Instruction::Sub, CLHS->getType(),
759 // X - undef -> undef
760 // undef - X -> undef
761 if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
762 return UndefValue::get(Op0->getType());
765 if (match(Op1, m_Zero()))
770 return Constant::getNullValue(Op0->getType());
775 if (match(Op0, m_Mul(m_Specific(Op1), m_ConstantInt<2>())) ||
776 match(Op0, m_Shl(m_Specific(Op1), m_One())))
779 // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
780 // For example, (X + Y) - Y -> X; (Y + X) - Y -> X
781 Value *Y = 0, *Z = Op1;
782 if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z
783 // See if "V === Y - Z" simplifies.
784 if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, Q, MaxRecurse-1))
785 // It does! Now see if "X + V" simplifies.
786 if (Value *W = SimplifyBinOp(Instruction::Add, X, V, 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 "Y + V" simplifies.
794 if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, Q, MaxRecurse-1)) {
795 // It does, we successfully reassociated!
801 // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
802 // For example, X - (X + 1) -> -1
804 if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z)
805 // See if "V === X - Y" simplifies.
806 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
807 // It does! Now see if "V - Z" simplifies.
808 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, Q, MaxRecurse-1)) {
809 // It does, we successfully reassociated!
813 // See if "V === X - Z" simplifies.
814 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
815 // It does! Now see if "V - Y" simplifies.
816 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, Q, MaxRecurse-1)) {
817 // It does, we successfully reassociated!
823 // Z - (X - Y) -> (Z - X) + Y if everything simplifies.
824 // For example, X - (X - Y) -> Y.
826 if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y)
827 // See if "V === Z - X" simplifies.
828 if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, Q, MaxRecurse-1))
829 // It does! Now see if "V + Y" simplifies.
830 if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, Q, MaxRecurse-1)) {
831 // It does, we successfully reassociated!
836 // trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies.
837 if (MaxRecurse && match(Op0, m_Trunc(m_Value(X))) &&
838 match(Op1, m_Trunc(m_Value(Y))))
839 if (X->getType() == Y->getType())
840 // See if "V === X - Y" simplifies.
841 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
842 // It does! Now see if "trunc V" simplifies.
843 if (Value *W = SimplifyTruncInst(V, Op0->getType(), Q, MaxRecurse-1))
844 // It does, return the simplified "trunc V".
847 // Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...).
848 if (Q.TD && match(Op0, m_PtrToInt(m_Value(X))) &&
849 match(Op1, m_PtrToInt(m_Value(Y))))
850 if (Constant *Result = computePointerDifference(*Q.TD, X, Y))
851 return ConstantExpr::getIntegerCast(Result, Op0->getType(), true);
853 // Mul distributes over Sub. Try some generic simplifications based on this.
854 if (Value *V = FactorizeBinOp(Instruction::Sub, Op0, Op1, Instruction::Mul,
859 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
860 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
863 // Threading Sub over selects and phi nodes is pointless, so don't bother.
864 // Threading over the select in "A - select(cond, B, C)" means evaluating
865 // "A-B" and "A-C" and seeing if they are equal; but they are equal if and
866 // only if B and C are equal. If B and C are equal then (since we assume
867 // that operands have already been simplified) "select(cond, B, C)" should
868 // have been simplified to the common value of B and C already. Analysing
869 // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly
870 // for threading over phi nodes.
875 Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
876 const TargetData *TD, const TargetLibraryInfo *TLI,
877 const DominatorTree *DT) {
878 return ::SimplifySubInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT),
882 /// SimplifyMulInst - Given operands for a Mul, see if we can
883 /// fold the result. If not, this returns null.
884 static Value *SimplifyMulInst(Value *Op0, Value *Op1, const Query &Q,
885 unsigned MaxRecurse) {
886 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
887 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
888 Constant *Ops[] = { CLHS, CRHS };
889 return ConstantFoldInstOperands(Instruction::Mul, CLHS->getType(),
893 // Canonicalize the constant to the RHS.
898 if (match(Op1, m_Undef()))
899 return Constant::getNullValue(Op0->getType());
902 if (match(Op1, m_Zero()))
906 if (match(Op1, m_One()))
909 // (X / Y) * Y -> X if the division is exact.
911 if (match(Op0, m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y
912 match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0))))) // Y * (X / Y)
916 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
917 if (Value *V = SimplifyAndInst(Op0, Op1, Q, MaxRecurse-1))
920 // Try some generic simplifications for associative operations.
921 if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, Q,
925 // Mul distributes over Add. Try some generic simplifications based on this.
926 if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add,
930 // If the operation is with the result of a select instruction, check whether
931 // operating on either branch of the select always yields the same value.
932 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
933 if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, Q,
937 // If the operation is with the result of a phi instruction, check whether
938 // operating on all incoming values of the phi always yields the same value.
939 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
940 if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, Q,
947 Value *llvm::SimplifyMulInst(Value *Op0, Value *Op1, const TargetData *TD,
948 const TargetLibraryInfo *TLI,
949 const DominatorTree *DT) {
950 return ::SimplifyMulInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
953 /// SimplifyDiv - Given operands for an SDiv or UDiv, see if we can
954 /// fold the result. If not, this returns null.
955 static Value *SimplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
956 const Query &Q, unsigned MaxRecurse) {
957 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
958 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
959 Constant *Ops[] = { C0, C1 };
960 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI);
964 bool isSigned = Opcode == Instruction::SDiv;
966 // X / undef -> undef
967 if (match(Op1, m_Undef()))
971 if (match(Op0, m_Undef()))
972 return Constant::getNullValue(Op0->getType());
974 // 0 / X -> 0, we don't need to preserve faults!
975 if (match(Op0, m_Zero()))
979 if (match(Op1, m_One()))
982 if (Op0->getType()->isIntegerTy(1))
983 // It can't be division by zero, hence it must be division by one.
988 return ConstantInt::get(Op0->getType(), 1);
990 // (X * Y) / Y -> X if the multiplication does not overflow.
991 Value *X = 0, *Y = 0;
992 if (match(Op0, m_Mul(m_Value(X), m_Value(Y))) && (X == Op1 || Y == Op1)) {
993 if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1
994 OverflowingBinaryOperator *Mul = cast<OverflowingBinaryOperator>(Op0);
995 // If the Mul knows it does not overflow, then we are good to go.
996 if ((isSigned && Mul->hasNoSignedWrap()) ||
997 (!isSigned && Mul->hasNoUnsignedWrap()))
999 // If X has the form X = A / Y then X * Y cannot overflow.
1000 if (BinaryOperator *Div = dyn_cast<BinaryOperator>(X))
1001 if (Div->getOpcode() == Opcode && Div->getOperand(1) == Y)
1005 // (X rem Y) / Y -> 0
1006 if ((isSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1007 (!isSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1008 return Constant::getNullValue(Op0->getType());
1010 // If the operation is with the result of a select instruction, check whether
1011 // operating on either branch of the select always yields the same value.
1012 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1013 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1016 // If the operation is with the result of a phi instruction, check whether
1017 // operating on all incoming values of the phi always yields the same value.
1018 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1019 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1025 /// SimplifySDivInst - Given operands for an SDiv, see if we can
1026 /// fold the result. If not, this returns null.
1027 static Value *SimplifySDivInst(Value *Op0, Value *Op1, const Query &Q,
1028 unsigned MaxRecurse) {
1029 if (Value *V = SimplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse))
1035 Value *llvm::SimplifySDivInst(Value *Op0, Value *Op1, const TargetData *TD,
1036 const TargetLibraryInfo *TLI,
1037 const DominatorTree *DT) {
1038 return ::SimplifySDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1041 /// SimplifyUDivInst - Given operands for a UDiv, see if we can
1042 /// fold the result. If not, this returns null.
1043 static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const Query &Q,
1044 unsigned MaxRecurse) {
1045 if (Value *V = SimplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse))
1051 Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const TargetData *TD,
1052 const TargetLibraryInfo *TLI,
1053 const DominatorTree *DT) {
1054 return ::SimplifyUDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1057 static Value *SimplifyFDivInst(Value *Op0, Value *Op1, const Query &Q,
1059 // undef / X -> undef (the undef could be a snan).
1060 if (match(Op0, m_Undef()))
1063 // X / undef -> undef
1064 if (match(Op1, m_Undef()))
1070 Value *llvm::SimplifyFDivInst(Value *Op0, Value *Op1, const TargetData *TD,
1071 const TargetLibraryInfo *TLI,
1072 const DominatorTree *DT) {
1073 return ::SimplifyFDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1076 /// SimplifyRem - Given operands for an SRem or URem, see if we can
1077 /// fold the result. If not, this returns null.
1078 static Value *SimplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
1079 const Query &Q, unsigned MaxRecurse) {
1080 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1081 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1082 Constant *Ops[] = { C0, C1 };
1083 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI);
1087 // X % undef -> undef
1088 if (match(Op1, m_Undef()))
1092 if (match(Op0, m_Undef()))
1093 return Constant::getNullValue(Op0->getType());
1095 // 0 % X -> 0, we don't need to preserve faults!
1096 if (match(Op0, m_Zero()))
1099 // X % 0 -> undef, we don't need to preserve faults!
1100 if (match(Op1, m_Zero()))
1101 return UndefValue::get(Op0->getType());
1104 if (match(Op1, m_One()))
1105 return Constant::getNullValue(Op0->getType());
1107 if (Op0->getType()->isIntegerTy(1))
1108 // It can't be remainder by zero, hence it must be remainder by one.
1109 return Constant::getNullValue(Op0->getType());
1113 return Constant::getNullValue(Op0->getType());
1115 // If the operation is with the result of a select instruction, check whether
1116 // operating on either branch of the select always yields the same value.
1117 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1118 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1121 // If the operation is with the result of a phi instruction, check whether
1122 // operating on all incoming values of the phi always yields the same value.
1123 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1124 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1130 /// SimplifySRemInst - Given operands for an SRem, see if we can
1131 /// fold the result. If not, this returns null.
1132 static Value *SimplifySRemInst(Value *Op0, Value *Op1, const Query &Q,
1133 unsigned MaxRecurse) {
1134 if (Value *V = SimplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse))
1140 Value *llvm::SimplifySRemInst(Value *Op0, Value *Op1, const TargetData *TD,
1141 const TargetLibraryInfo *TLI,
1142 const DominatorTree *DT) {
1143 return ::SimplifySRemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1146 /// SimplifyURemInst - Given operands for a URem, see if we can
1147 /// fold the result. If not, this returns null.
1148 static Value *SimplifyURemInst(Value *Op0, Value *Op1, const Query &Q,
1149 unsigned MaxRecurse) {
1150 if (Value *V = SimplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse))
1156 Value *llvm::SimplifyURemInst(Value *Op0, Value *Op1, const TargetData *TD,
1157 const TargetLibraryInfo *TLI,
1158 const DominatorTree *DT) {
1159 return ::SimplifyURemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1162 static Value *SimplifyFRemInst(Value *Op0, Value *Op1, const Query &,
1164 // undef % X -> undef (the undef could be a snan).
1165 if (match(Op0, m_Undef()))
1168 // X % undef -> undef
1169 if (match(Op1, m_Undef()))
1175 Value *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, const TargetData *TD,
1176 const TargetLibraryInfo *TLI,
1177 const DominatorTree *DT) {
1178 return ::SimplifyFRemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1181 /// SimplifyShift - Given operands for an Shl, LShr or AShr, see if we can
1182 /// fold the result. If not, this returns null.
1183 static Value *SimplifyShift(unsigned Opcode, Value *Op0, Value *Op1,
1184 const Query &Q, unsigned MaxRecurse) {
1185 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1186 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1187 Constant *Ops[] = { C0, C1 };
1188 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI);
1192 // 0 shift by X -> 0
1193 if (match(Op0, m_Zero()))
1196 // X shift by 0 -> X
1197 if (match(Op1, m_Zero()))
1200 // X shift by undef -> undef because it may shift by the bitwidth.
1201 if (match(Op1, m_Undef()))
1204 // Shifting by the bitwidth or more is undefined.
1205 if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1))
1206 if (CI->getValue().getLimitedValue() >=
1207 Op0->getType()->getScalarSizeInBits())
1208 return UndefValue::get(Op0->getType());
1210 // If the operation is with the result of a select instruction, check whether
1211 // operating on either branch of the select always yields the same value.
1212 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1213 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1216 // If the operation is with the result of a phi instruction, check whether
1217 // operating on all incoming values of the phi always yields the same value.
1218 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1219 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1225 /// SimplifyShlInst - Given operands for an Shl, see if we can
1226 /// fold the result. If not, this returns null.
1227 static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1228 const Query &Q, unsigned MaxRecurse) {
1229 if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse))
1233 if (match(Op0, m_Undef()))
1234 return Constant::getNullValue(Op0->getType());
1236 // (X >> A) << A -> X
1238 if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
1243 Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1244 const TargetData *TD, const TargetLibraryInfo *TLI,
1245 const DominatorTree *DT) {
1246 return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT),
1250 /// SimplifyLShrInst - Given operands for an LShr, see if we can
1251 /// fold the result. If not, this returns null.
1252 static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1253 const Query &Q, unsigned MaxRecurse) {
1254 if (Value *V = SimplifyShift(Instruction::LShr, Op0, Op1, Q, MaxRecurse))
1258 if (match(Op0, m_Undef()))
1259 return Constant::getNullValue(Op0->getType());
1261 // (X << A) >> A -> X
1263 if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) &&
1264 cast<OverflowingBinaryOperator>(Op0)->hasNoUnsignedWrap())
1270 Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1271 const TargetData *TD,
1272 const TargetLibraryInfo *TLI,
1273 const DominatorTree *DT) {
1274 return ::SimplifyLShrInst(Op0, Op1, isExact, Query (TD, TLI, DT),
1278 /// SimplifyAShrInst - Given operands for an AShr, see if we can
1279 /// fold the result. If not, this returns null.
1280 static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1281 const Query &Q, unsigned MaxRecurse) {
1282 if (Value *V = SimplifyShift(Instruction::AShr, Op0, Op1, Q, MaxRecurse))
1285 // all ones >>a X -> all ones
1286 if (match(Op0, m_AllOnes()))
1289 // undef >>a X -> all ones
1290 if (match(Op0, m_Undef()))
1291 return Constant::getAllOnesValue(Op0->getType());
1293 // (X << A) >> A -> X
1295 if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) &&
1296 cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap())
1302 Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1303 const TargetData *TD,
1304 const TargetLibraryInfo *TLI,
1305 const DominatorTree *DT) {
1306 return ::SimplifyAShrInst(Op0, Op1, isExact, Query (TD, TLI, DT),
1310 /// SimplifyAndInst - Given operands for an And, see if we can
1311 /// fold the result. If not, this returns null.
1312 static Value *SimplifyAndInst(Value *Op0, Value *Op1, const Query &Q,
1313 unsigned MaxRecurse) {
1314 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1315 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1316 Constant *Ops[] = { CLHS, CRHS };
1317 return ConstantFoldInstOperands(Instruction::And, CLHS->getType(),
1321 // Canonicalize the constant to the RHS.
1322 std::swap(Op0, Op1);
1326 if (match(Op1, m_Undef()))
1327 return Constant::getNullValue(Op0->getType());
1334 if (match(Op1, m_Zero()))
1338 if (match(Op1, m_AllOnes()))
1341 // A & ~A = ~A & A = 0
1342 if (match(Op0, m_Not(m_Specific(Op1))) ||
1343 match(Op1, m_Not(m_Specific(Op0))))
1344 return Constant::getNullValue(Op0->getType());
1347 Value *A = 0, *B = 0;
1348 if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
1349 (A == Op1 || B == Op1))
1353 if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
1354 (A == Op0 || B == Op0))
1357 // A & (-A) = A if A is a power of two or zero.
1358 if (match(Op0, m_Neg(m_Specific(Op1))) ||
1359 match(Op1, m_Neg(m_Specific(Op0)))) {
1360 if (isPowerOfTwo(Op0, Q.TD, /*OrZero*/true))
1362 if (isPowerOfTwo(Op1, Q.TD, /*OrZero*/true))
1366 // Try some generic simplifications for associative operations.
1367 if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
1371 // And distributes over Or. Try some generic simplifications based on this.
1372 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1376 // And distributes over Xor. Try some generic simplifications based on this.
1377 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
1381 // Or distributes over And. Try some generic simplifications based on this.
1382 if (Value *V = FactorizeBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1386 // If the operation is with the result of a select instruction, check whether
1387 // operating on either branch of the select always yields the same value.
1388 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1389 if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
1393 // If the operation is with the result of a phi instruction, check whether
1394 // operating on all incoming values of the phi always yields the same value.
1395 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1396 if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
1403 Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const TargetData *TD,
1404 const TargetLibraryInfo *TLI,
1405 const DominatorTree *DT) {
1406 return ::SimplifyAndInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1409 /// SimplifyOrInst - Given operands for an Or, see if we can
1410 /// fold the result. If not, this returns null.
1411 static Value *SimplifyOrInst(Value *Op0, Value *Op1, const Query &Q,
1412 unsigned MaxRecurse) {
1413 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1414 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1415 Constant *Ops[] = { CLHS, CRHS };
1416 return ConstantFoldInstOperands(Instruction::Or, CLHS->getType(),
1420 // Canonicalize the constant to the RHS.
1421 std::swap(Op0, Op1);
1425 if (match(Op1, m_Undef()))
1426 return Constant::getAllOnesValue(Op0->getType());
1433 if (match(Op1, m_Zero()))
1437 if (match(Op1, m_AllOnes()))
1440 // A | ~A = ~A | A = -1
1441 if (match(Op0, m_Not(m_Specific(Op1))) ||
1442 match(Op1, m_Not(m_Specific(Op0))))
1443 return Constant::getAllOnesValue(Op0->getType());
1446 Value *A = 0, *B = 0;
1447 if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
1448 (A == Op1 || B == Op1))
1452 if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
1453 (A == Op0 || B == Op0))
1456 // ~(A & ?) | A = -1
1457 if (match(Op0, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1458 (A == Op1 || B == Op1))
1459 return Constant::getAllOnesValue(Op1->getType());
1461 // A | ~(A & ?) = -1
1462 if (match(Op1, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1463 (A == Op0 || B == Op0))
1464 return Constant::getAllOnesValue(Op0->getType());
1466 // Try some generic simplifications for associative operations.
1467 if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
1471 // Or distributes over And. Try some generic simplifications based on this.
1472 if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
1476 // And distributes over Or. Try some generic simplifications based on this.
1477 if (Value *V = FactorizeBinOp(Instruction::Or, Op0, Op1, Instruction::And,
1481 // If the operation is with the result of a select instruction, check whether
1482 // operating on either branch of the select always yields the same value.
1483 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1484 if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
1488 // If the operation is with the result of a phi instruction, check whether
1489 // operating on all incoming values of the phi always yields the same value.
1490 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1491 if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
1497 Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const TargetData *TD,
1498 const TargetLibraryInfo *TLI,
1499 const DominatorTree *DT) {
1500 return ::SimplifyOrInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1503 /// SimplifyXorInst - Given operands for a Xor, see if we can
1504 /// fold the result. If not, this returns null.
1505 static Value *SimplifyXorInst(Value *Op0, Value *Op1, const Query &Q,
1506 unsigned MaxRecurse) {
1507 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1508 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1509 Constant *Ops[] = { CLHS, CRHS };
1510 return ConstantFoldInstOperands(Instruction::Xor, CLHS->getType(),
1514 // Canonicalize the constant to the RHS.
1515 std::swap(Op0, Op1);
1518 // A ^ undef -> undef
1519 if (match(Op1, m_Undef()))
1523 if (match(Op1, m_Zero()))
1528 return Constant::getNullValue(Op0->getType());
1530 // A ^ ~A = ~A ^ A = -1
1531 if (match(Op0, m_Not(m_Specific(Op1))) ||
1532 match(Op1, m_Not(m_Specific(Op0))))
1533 return Constant::getAllOnesValue(Op0->getType());
1535 // Try some generic simplifications for associative operations.
1536 if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
1540 // And distributes over Xor. Try some generic simplifications based on this.
1541 if (Value *V = FactorizeBinOp(Instruction::Xor, Op0, Op1, Instruction::And,
1545 // Threading Xor over selects and phi nodes is pointless, so don't bother.
1546 // Threading over the select in "A ^ select(cond, B, C)" means evaluating
1547 // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
1548 // only if B and C are equal. If B and C are equal then (since we assume
1549 // that operands have already been simplified) "select(cond, B, C)" should
1550 // have been simplified to the common value of B and C already. Analysing
1551 // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
1552 // for threading over phi nodes.
1557 Value *llvm::SimplifyXorInst(Value *Op0, Value *Op1, const TargetData *TD,
1558 const TargetLibraryInfo *TLI,
1559 const DominatorTree *DT) {
1560 return ::SimplifyXorInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
1563 static Type *GetCompareTy(Value *Op) {
1564 return CmpInst::makeCmpResultType(Op->getType());
1567 /// ExtractEquivalentCondition - Rummage around inside V looking for something
1568 /// equivalent to the comparison "LHS Pred RHS". Return such a value if found,
1569 /// otherwise return null. Helper function for analyzing max/min idioms.
1570 static Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred,
1571 Value *LHS, Value *RHS) {
1572 SelectInst *SI = dyn_cast<SelectInst>(V);
1575 CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
1578 Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
1579 if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
1581 if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
1582 LHS == CmpRHS && RHS == CmpLHS)
1588 /// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
1589 /// fold the result. If not, this returns null.
1590 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
1591 const Query &Q, unsigned MaxRecurse) {
1592 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
1593 assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
1595 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
1596 if (Constant *CRHS = dyn_cast<Constant>(RHS))
1597 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.TD, Q.TLI);
1599 // If we have a constant, make sure it is on the RHS.
1600 std::swap(LHS, RHS);
1601 Pred = CmpInst::getSwappedPredicate(Pred);
1604 Type *ITy = GetCompareTy(LHS); // The return type.
1605 Type *OpTy = LHS->getType(); // The operand type.
1607 // icmp X, X -> true/false
1608 // X icmp undef -> true/false. For example, icmp ugt %X, undef -> false
1609 // because X could be 0.
1610 if (LHS == RHS || isa<UndefValue>(RHS))
1611 return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
1613 // Special case logic when the operands have i1 type.
1614 if (OpTy->getScalarType()->isIntegerTy(1)) {
1617 case ICmpInst::ICMP_EQ:
1619 if (match(RHS, m_One()))
1622 case ICmpInst::ICMP_NE:
1624 if (match(RHS, m_Zero()))
1627 case ICmpInst::ICMP_UGT:
1629 if (match(RHS, m_Zero()))
1632 case ICmpInst::ICMP_UGE:
1634 if (match(RHS, m_One()))
1637 case ICmpInst::ICMP_SLT:
1639 if (match(RHS, m_Zero()))
1642 case ICmpInst::ICMP_SLE:
1644 if (match(RHS, m_One()))
1650 // icmp <object*>, <object*/null> - Different identified objects have
1651 // different addresses (unless null), and what's more the address of an
1652 // identified local is never equal to another argument (again, barring null).
1653 // Note that generalizing to the case where LHS is a global variable address
1654 // or null is pointless, since if both LHS and RHS are constants then we
1655 // already constant folded the compare, and if only one of them is then we
1656 // moved it to RHS already.
1657 Value *LHSPtr = LHS->stripPointerCasts();
1658 Value *RHSPtr = RHS->stripPointerCasts();
1659 if (LHSPtr == RHSPtr)
1660 return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
1662 // Be more aggressive about stripping pointer adjustments when checking a
1663 // comparison of an alloca address to another object. We can rip off all
1664 // inbounds GEP operations, even if they are variable.
1665 LHSPtr = LHSPtr->stripInBoundsOffsets();
1666 if (llvm::isIdentifiedObject(LHSPtr)) {
1667 RHSPtr = RHSPtr->stripInBoundsOffsets();
1668 if (llvm::isKnownNonNull(LHSPtr) || llvm::isKnownNonNull(RHSPtr)) {
1669 // If both sides are different identified objects, they aren't equal
1670 // unless they're null.
1671 if (LHSPtr != RHSPtr && llvm::isIdentifiedObject(RHSPtr) &&
1672 Pred == CmpInst::ICMP_EQ)
1673 return ConstantInt::get(ITy, false);
1675 // A local identified object (alloca or noalias call) can't equal any
1676 // incoming argument, unless they're both null.
1677 if (isa<Instruction>(LHSPtr) && isa<Argument>(RHSPtr) &&
1678 Pred == CmpInst::ICMP_EQ)
1679 return ConstantInt::get(ITy, false);
1682 // Assume that the constant null is on the right.
1683 if (llvm::isKnownNonNull(LHSPtr) && isa<ConstantPointerNull>(RHSPtr)) {
1684 if (Pred == CmpInst::ICMP_EQ)
1685 return ConstantInt::get(ITy, false);
1686 else if (Pred == CmpInst::ICMP_NE)
1687 return ConstantInt::get(ITy, true);
1689 } else if (isa<Argument>(LHSPtr)) {
1690 RHSPtr = RHSPtr->stripInBoundsOffsets();
1691 // An alloca can't be equal to an argument.
1692 if (isa<AllocaInst>(RHSPtr)) {
1693 if (Pred == CmpInst::ICMP_EQ)
1694 return ConstantInt::get(ITy, false);
1695 else if (Pred == CmpInst::ICMP_NE)
1696 return ConstantInt::get(ITy, true);
1700 // If we are comparing with zero then try hard since this is a common case.
1701 if (match(RHS, m_Zero())) {
1702 bool LHSKnownNonNegative, LHSKnownNegative;
1704 default: llvm_unreachable("Unknown ICmp predicate!");
1705 case ICmpInst::ICMP_ULT:
1706 return getFalse(ITy);
1707 case ICmpInst::ICMP_UGE:
1708 return getTrue(ITy);
1709 case ICmpInst::ICMP_EQ:
1710 case ICmpInst::ICMP_ULE:
1711 if (isKnownNonZero(LHS, Q.TD))
1712 return getFalse(ITy);
1714 case ICmpInst::ICMP_NE:
1715 case ICmpInst::ICMP_UGT:
1716 if (isKnownNonZero(LHS, Q.TD))
1717 return getTrue(ITy);
1719 case ICmpInst::ICMP_SLT:
1720 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1721 if (LHSKnownNegative)
1722 return getTrue(ITy);
1723 if (LHSKnownNonNegative)
1724 return getFalse(ITy);
1726 case ICmpInst::ICMP_SLE:
1727 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1728 if (LHSKnownNegative)
1729 return getTrue(ITy);
1730 if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.TD))
1731 return getFalse(ITy);
1733 case ICmpInst::ICMP_SGE:
1734 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1735 if (LHSKnownNegative)
1736 return getFalse(ITy);
1737 if (LHSKnownNonNegative)
1738 return getTrue(ITy);
1740 case ICmpInst::ICMP_SGT:
1741 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
1742 if (LHSKnownNegative)
1743 return getFalse(ITy);
1744 if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.TD))
1745 return getTrue(ITy);
1750 // See if we are doing a comparison with a constant integer.
1751 if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
1752 // Rule out tautological comparisons (eg., ult 0 or uge 0).
1753 ConstantRange RHS_CR = ICmpInst::makeConstantRange(Pred, CI->getValue());
1754 if (RHS_CR.isEmptySet())
1755 return ConstantInt::getFalse(CI->getContext());
1756 if (RHS_CR.isFullSet())
1757 return ConstantInt::getTrue(CI->getContext());
1759 // Many binary operators with constant RHS have easy to compute constant
1760 // range. Use them to check whether the comparison is a tautology.
1761 uint32_t Width = CI->getBitWidth();
1762 APInt Lower = APInt(Width, 0);
1763 APInt Upper = APInt(Width, 0);
1765 if (match(LHS, m_URem(m_Value(), m_ConstantInt(CI2)))) {
1766 // 'urem x, CI2' produces [0, CI2).
1767 Upper = CI2->getValue();
1768 } else if (match(LHS, m_SRem(m_Value(), m_ConstantInt(CI2)))) {
1769 // 'srem x, CI2' produces (-|CI2|, |CI2|).
1770 Upper = CI2->getValue().abs();
1771 Lower = (-Upper) + 1;
1772 } else if (match(LHS, m_UDiv(m_ConstantInt(CI2), m_Value()))) {
1773 // 'udiv CI2, x' produces [0, CI2].
1774 Upper = CI2->getValue() + 1;
1775 } else if (match(LHS, m_UDiv(m_Value(), m_ConstantInt(CI2)))) {
1776 // 'udiv x, CI2' produces [0, UINT_MAX / CI2].
1777 APInt NegOne = APInt::getAllOnesValue(Width);
1779 Upper = NegOne.udiv(CI2->getValue()) + 1;
1780 } else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) {
1781 // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2].
1782 APInt IntMin = APInt::getSignedMinValue(Width);
1783 APInt IntMax = APInt::getSignedMaxValue(Width);
1784 APInt Val = CI2->getValue().abs();
1785 if (!Val.isMinValue()) {
1786 Lower = IntMin.sdiv(Val);
1787 Upper = IntMax.sdiv(Val) + 1;
1789 } else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) {
1790 // 'lshr x, CI2' produces [0, UINT_MAX >> CI2].
1791 APInt NegOne = APInt::getAllOnesValue(Width);
1792 if (CI2->getValue().ult(Width))
1793 Upper = NegOne.lshr(CI2->getValue()) + 1;
1794 } else if (match(LHS, m_AShr(m_Value(), m_ConstantInt(CI2)))) {
1795 // 'ashr x, CI2' produces [INT_MIN >> CI2, INT_MAX >> CI2].
1796 APInt IntMin = APInt::getSignedMinValue(Width);
1797 APInt IntMax = APInt::getSignedMaxValue(Width);
1798 if (CI2->getValue().ult(Width)) {
1799 Lower = IntMin.ashr(CI2->getValue());
1800 Upper = IntMax.ashr(CI2->getValue()) + 1;
1802 } else if (match(LHS, m_Or(m_Value(), m_ConstantInt(CI2)))) {
1803 // 'or x, CI2' produces [CI2, UINT_MAX].
1804 Lower = CI2->getValue();
1805 } else if (match(LHS, m_And(m_Value(), m_ConstantInt(CI2)))) {
1806 // 'and x, CI2' produces [0, CI2].
1807 Upper = CI2->getValue() + 1;
1809 if (Lower != Upper) {
1810 ConstantRange LHS_CR = ConstantRange(Lower, Upper);
1811 if (RHS_CR.contains(LHS_CR))
1812 return ConstantInt::getTrue(RHS->getContext());
1813 if (RHS_CR.inverse().contains(LHS_CR))
1814 return ConstantInt::getFalse(RHS->getContext());
1818 // Compare of cast, for example (zext X) != 0 -> X != 0
1819 if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
1820 Instruction *LI = cast<CastInst>(LHS);
1821 Value *SrcOp = LI->getOperand(0);
1822 Type *SrcTy = SrcOp->getType();
1823 Type *DstTy = LI->getType();
1825 // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
1826 // if the integer type is the same size as the pointer type.
1827 if (MaxRecurse && Q.TD && isa<PtrToIntInst>(LI) &&
1828 Q.TD->getPointerSizeInBits() == DstTy->getPrimitiveSizeInBits()) {
1829 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
1830 // Transfer the cast to the constant.
1831 if (Value *V = SimplifyICmpInst(Pred, SrcOp,
1832 ConstantExpr::getIntToPtr(RHSC, SrcTy),
1835 } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
1836 if (RI->getOperand(0)->getType() == SrcTy)
1837 // Compare without the cast.
1838 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
1844 if (isa<ZExtInst>(LHS)) {
1845 // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
1847 if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
1848 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
1849 // Compare X and Y. Note that signed predicates become unsigned.
1850 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
1851 SrcOp, RI->getOperand(0), Q,
1855 // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
1856 // too. If not, then try to deduce the result of the comparison.
1857 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
1858 // Compute the constant that would happen if we truncated to SrcTy then
1859 // reextended to DstTy.
1860 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
1861 Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
1863 // If the re-extended constant didn't change then this is effectively
1864 // also a case of comparing two zero-extended values.
1865 if (RExt == CI && MaxRecurse)
1866 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
1867 SrcOp, Trunc, Q, MaxRecurse-1))
1870 // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
1871 // there. Use this to work out the result of the comparison.
1874 default: llvm_unreachable("Unknown ICmp predicate!");
1876 case ICmpInst::ICMP_EQ:
1877 case ICmpInst::ICMP_UGT:
1878 case ICmpInst::ICMP_UGE:
1879 return ConstantInt::getFalse(CI->getContext());
1881 case ICmpInst::ICMP_NE:
1882 case ICmpInst::ICMP_ULT:
1883 case ICmpInst::ICMP_ULE:
1884 return ConstantInt::getTrue(CI->getContext());
1886 // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
1887 // is non-negative then LHS <s RHS.
1888 case ICmpInst::ICMP_SGT:
1889 case ICmpInst::ICMP_SGE:
1890 return CI->getValue().isNegative() ?
1891 ConstantInt::getTrue(CI->getContext()) :
1892 ConstantInt::getFalse(CI->getContext());
1894 case ICmpInst::ICMP_SLT:
1895 case ICmpInst::ICMP_SLE:
1896 return CI->getValue().isNegative() ?
1897 ConstantInt::getFalse(CI->getContext()) :
1898 ConstantInt::getTrue(CI->getContext());
1904 if (isa<SExtInst>(LHS)) {
1905 // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
1907 if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
1908 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
1909 // Compare X and Y. Note that the predicate does not change.
1910 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
1914 // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
1915 // too. If not, then try to deduce the result of the comparison.
1916 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
1917 // Compute the constant that would happen if we truncated to SrcTy then
1918 // reextended to DstTy.
1919 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
1920 Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
1922 // If the re-extended constant didn't change then this is effectively
1923 // also a case of comparing two sign-extended values.
1924 if (RExt == CI && MaxRecurse)
1925 if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
1928 // Otherwise the upper bits of LHS are all equal, while RHS has varying
1929 // bits there. Use this to work out the result of the comparison.
1932 default: llvm_unreachable("Unknown ICmp predicate!");
1933 case ICmpInst::ICMP_EQ:
1934 return ConstantInt::getFalse(CI->getContext());
1935 case ICmpInst::ICMP_NE:
1936 return ConstantInt::getTrue(CI->getContext());
1938 // If RHS is non-negative then LHS <s RHS. If RHS is negative then
1940 case ICmpInst::ICMP_SGT:
1941 case ICmpInst::ICMP_SGE:
1942 return CI->getValue().isNegative() ?
1943 ConstantInt::getTrue(CI->getContext()) :
1944 ConstantInt::getFalse(CI->getContext());
1945 case ICmpInst::ICMP_SLT:
1946 case ICmpInst::ICMP_SLE:
1947 return CI->getValue().isNegative() ?
1948 ConstantInt::getFalse(CI->getContext()) :
1949 ConstantInt::getTrue(CI->getContext());
1951 // If LHS is non-negative then LHS <u RHS. If LHS is negative then
1953 case ICmpInst::ICMP_UGT:
1954 case ICmpInst::ICMP_UGE:
1955 // Comparison is true iff the LHS <s 0.
1957 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
1958 Constant::getNullValue(SrcTy),
1962 case ICmpInst::ICMP_ULT:
1963 case ICmpInst::ICMP_ULE:
1964 // Comparison is true iff the LHS >=s 0.
1966 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
1967 Constant::getNullValue(SrcTy),
1977 // Special logic for binary operators.
1978 BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
1979 BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
1980 if (MaxRecurse && (LBO || RBO)) {
1981 // Analyze the case when either LHS or RHS is an add instruction.
1982 Value *A = 0, *B = 0, *C = 0, *D = 0;
1983 // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
1984 bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
1985 if (LBO && LBO->getOpcode() == Instruction::Add) {
1986 A = LBO->getOperand(0); B = LBO->getOperand(1);
1987 NoLHSWrapProblem = ICmpInst::isEquality(Pred) ||
1988 (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
1989 (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
1991 if (RBO && RBO->getOpcode() == Instruction::Add) {
1992 C = RBO->getOperand(0); D = RBO->getOperand(1);
1993 NoRHSWrapProblem = ICmpInst::isEquality(Pred) ||
1994 (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
1995 (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
1998 // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
1999 if ((A == RHS || B == RHS) && NoLHSWrapProblem)
2000 if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
2001 Constant::getNullValue(RHS->getType()),
2005 // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
2006 if ((C == LHS || D == LHS) && NoRHSWrapProblem)
2007 if (Value *V = SimplifyICmpInst(Pred,
2008 Constant::getNullValue(LHS->getType()),
2009 C == LHS ? D : C, Q, MaxRecurse-1))
2012 // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
2013 if (A && C && (A == C || A == D || B == C || B == D) &&
2014 NoLHSWrapProblem && NoRHSWrapProblem) {
2015 // Determine Y and Z in the form icmp (X+Y), (X+Z).
2016 Value *Y = (A == C || A == D) ? B : A;
2017 Value *Z = (C == A || C == B) ? D : C;
2018 if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse-1))
2023 if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
2024 bool KnownNonNegative, KnownNegative;
2028 case ICmpInst::ICMP_SGT:
2029 case ICmpInst::ICMP_SGE:
2030 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.TD);
2031 if (!KnownNonNegative)
2034 case ICmpInst::ICMP_EQ:
2035 case ICmpInst::ICMP_UGT:
2036 case ICmpInst::ICMP_UGE:
2037 return getFalse(ITy);
2038 case ICmpInst::ICMP_SLT:
2039 case ICmpInst::ICMP_SLE:
2040 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.TD);
2041 if (!KnownNonNegative)
2044 case ICmpInst::ICMP_NE:
2045 case ICmpInst::ICMP_ULT:
2046 case ICmpInst::ICMP_ULE:
2047 return getTrue(ITy);
2050 if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
2051 bool KnownNonNegative, KnownNegative;
2055 case ICmpInst::ICMP_SGT:
2056 case ICmpInst::ICMP_SGE:
2057 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.TD);
2058 if (!KnownNonNegative)
2061 case ICmpInst::ICMP_NE:
2062 case ICmpInst::ICMP_UGT:
2063 case ICmpInst::ICMP_UGE:
2064 return getTrue(ITy);
2065 case ICmpInst::ICMP_SLT:
2066 case ICmpInst::ICMP_SLE:
2067 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.TD);
2068 if (!KnownNonNegative)
2071 case ICmpInst::ICMP_EQ:
2072 case ICmpInst::ICMP_ULT:
2073 case ICmpInst::ICMP_ULE:
2074 return getFalse(ITy);
2079 if (LBO && match(LBO, m_UDiv(m_Specific(RHS), m_Value()))) {
2080 // icmp pred (X /u Y), X
2081 if (Pred == ICmpInst::ICMP_UGT)
2082 return getFalse(ITy);
2083 if (Pred == ICmpInst::ICMP_ULE)
2084 return getTrue(ITy);
2087 if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
2088 LBO->getOperand(1) == RBO->getOperand(1)) {
2089 switch (LBO->getOpcode()) {
2091 case Instruction::UDiv:
2092 case Instruction::LShr:
2093 if (ICmpInst::isSigned(Pred))
2096 case Instruction::SDiv:
2097 case Instruction::AShr:
2098 if (!LBO->isExact() || !RBO->isExact())
2100 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2101 RBO->getOperand(0), Q, MaxRecurse-1))
2104 case Instruction::Shl: {
2105 bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
2106 bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
2109 if (!NSW && ICmpInst::isSigned(Pred))
2111 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
2112 RBO->getOperand(0), Q, MaxRecurse-1))
2119 // Simplify comparisons involving max/min.
2121 CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE;
2122 CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
2124 // Signed variants on "max(a,b)>=a -> true".
2125 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2126 if (A != RHS) std::swap(A, B); // smax(A, B) pred A.
2127 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2128 // We analyze this as smax(A, B) pred A.
2130 } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
2131 (A == LHS || B == LHS)) {
2132 if (A != LHS) std::swap(A, B); // A pred smax(A, B).
2133 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
2134 // We analyze this as smax(A, B) swapped-pred A.
2135 P = CmpInst::getSwappedPredicate(Pred);
2136 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2137 (A == RHS || B == RHS)) {
2138 if (A != RHS) std::swap(A, B); // smin(A, B) pred A.
2139 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2140 // We analyze this as smax(-A, -B) swapped-pred -A.
2141 // Note that we do not need to actually form -A or -B thanks to EqP.
2142 P = CmpInst::getSwappedPredicate(Pred);
2143 } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
2144 (A == LHS || B == LHS)) {
2145 if (A != LHS) std::swap(A, B); // A pred smin(A, B).
2146 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
2147 // We analyze this as smax(-A, -B) pred -A.
2148 // Note that we do not need to actually form -A or -B thanks to EqP.
2151 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2152 // Cases correspond to "max(A, B) p A".
2156 case CmpInst::ICMP_EQ:
2157 case CmpInst::ICMP_SLE:
2158 // Equivalent to "A EqP B". This may be the same as the condition tested
2159 // in the max/min; if so, we can just return that.
2160 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2162 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2164 // Otherwise, see if "A EqP B" simplifies.
2166 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2169 case CmpInst::ICMP_NE:
2170 case CmpInst::ICMP_SGT: {
2171 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2172 // Equivalent to "A InvEqP B". This may be the same as the condition
2173 // tested in the max/min; if so, we can just return that.
2174 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2176 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2178 // Otherwise, see if "A InvEqP B" simplifies.
2180 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2184 case CmpInst::ICMP_SGE:
2186 return getTrue(ITy);
2187 case CmpInst::ICMP_SLT:
2189 return getFalse(ITy);
2193 // Unsigned variants on "max(a,b)>=a -> true".
2194 P = CmpInst::BAD_ICMP_PREDICATE;
2195 if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2196 if (A != RHS) std::swap(A, B); // umax(A, B) pred A.
2197 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2198 // We analyze this as umax(A, B) pred A.
2200 } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
2201 (A == LHS || B == LHS)) {
2202 if (A != LHS) std::swap(A, B); // A pred umax(A, B).
2203 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2204 // We analyze this as umax(A, B) swapped-pred A.
2205 P = CmpInst::getSwappedPredicate(Pred);
2206 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2207 (A == RHS || B == RHS)) {
2208 if (A != RHS) std::swap(A, B); // umin(A, B) pred A.
2209 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2210 // We analyze this as umax(-A, -B) swapped-pred -A.
2211 // Note that we do not need to actually form -A or -B thanks to EqP.
2212 P = CmpInst::getSwappedPredicate(Pred);
2213 } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
2214 (A == LHS || B == LHS)) {
2215 if (A != LHS) std::swap(A, B); // A pred umin(A, B).
2216 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2217 // We analyze this as umax(-A, -B) pred -A.
2218 // Note that we do not need to actually form -A or -B thanks to EqP.
2221 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2222 // Cases correspond to "max(A, B) p A".
2226 case CmpInst::ICMP_EQ:
2227 case CmpInst::ICMP_ULE:
2228 // Equivalent to "A EqP B". This may be the same as the condition tested
2229 // in the max/min; if so, we can just return that.
2230 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2232 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2234 // Otherwise, see if "A EqP B" simplifies.
2236 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
2239 case CmpInst::ICMP_NE:
2240 case CmpInst::ICMP_UGT: {
2241 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2242 // Equivalent to "A InvEqP B". This may be the same as the condition
2243 // tested in the max/min; if so, we can just return that.
2244 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2246 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2248 // Otherwise, see if "A InvEqP B" simplifies.
2250 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
2254 case CmpInst::ICMP_UGE:
2256 return getTrue(ITy);
2257 case CmpInst::ICMP_ULT:
2259 return getFalse(ITy);
2263 // Variants on "max(x,y) >= min(x,z)".
2265 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
2266 match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
2267 (A == C || A == D || B == C || B == D)) {
2268 // max(x, ?) pred min(x, ?).
2269 if (Pred == CmpInst::ICMP_SGE)
2271 return getTrue(ITy);
2272 if (Pred == CmpInst::ICMP_SLT)
2274 return getFalse(ITy);
2275 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2276 match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
2277 (A == C || A == D || B == C || B == D)) {
2278 // min(x, ?) pred max(x, ?).
2279 if (Pred == CmpInst::ICMP_SLE)
2281 return getTrue(ITy);
2282 if (Pred == CmpInst::ICMP_SGT)
2284 return getFalse(ITy);
2285 } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
2286 match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
2287 (A == C || A == D || B == C || B == D)) {
2288 // max(x, ?) pred min(x, ?).
2289 if (Pred == CmpInst::ICMP_UGE)
2291 return getTrue(ITy);
2292 if (Pred == CmpInst::ICMP_ULT)
2294 return getFalse(ITy);
2295 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2296 match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
2297 (A == C || A == D || B == C || B == D)) {
2298 // min(x, ?) pred max(x, ?).
2299 if (Pred == CmpInst::ICMP_ULE)
2301 return getTrue(ITy);
2302 if (Pred == CmpInst::ICMP_UGT)
2304 return getFalse(ITy);
2307 // Simplify comparisons of GEPs.
2308 if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
2309 if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
2310 if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
2311 GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
2312 (ICmpInst::isEquality(Pred) ||
2313 (GLHS->isInBounds() && GRHS->isInBounds() &&
2314 Pred == ICmpInst::getSignedPredicate(Pred)))) {
2315 // The bases are equal and the indices are constant. Build a constant
2316 // expression GEP with the same indices and a null base pointer to see
2317 // what constant folding can make out of it.
2318 Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
2319 SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
2320 Constant *NewLHS = ConstantExpr::getGetElementPtr(Null, IndicesLHS);
2322 SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
2323 Constant *NewRHS = ConstantExpr::getGetElementPtr(Null, IndicesRHS);
2324 return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
2329 // If the comparison is with the result of a select instruction, check whether
2330 // comparing with either branch of the select always yields the same value.
2331 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2332 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
2335 // If the comparison is with the result of a phi instruction, check whether
2336 // doing the compare with each incoming phi value yields a common result.
2337 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2338 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
2344 Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2345 const TargetData *TD,
2346 const TargetLibraryInfo *TLI,
2347 const DominatorTree *DT) {
2348 return ::SimplifyICmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
2352 /// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can
2353 /// fold the result. If not, this returns null.
2354 static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2355 const Query &Q, unsigned MaxRecurse) {
2356 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
2357 assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
2359 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
2360 if (Constant *CRHS = dyn_cast<Constant>(RHS))
2361 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.TD, Q.TLI);
2363 // If we have a constant, make sure it is on the RHS.
2364 std::swap(LHS, RHS);
2365 Pred = CmpInst::getSwappedPredicate(Pred);
2368 // Fold trivial predicates.
2369 if (Pred == FCmpInst::FCMP_FALSE)
2370 return ConstantInt::get(GetCompareTy(LHS), 0);
2371 if (Pred == FCmpInst::FCMP_TRUE)
2372 return ConstantInt::get(GetCompareTy(LHS), 1);
2374 if (isa<UndefValue>(RHS)) // fcmp pred X, undef -> undef
2375 return UndefValue::get(GetCompareTy(LHS));
2377 // fcmp x,x -> true/false. Not all compares are foldable.
2379 if (CmpInst::isTrueWhenEqual(Pred))
2380 return ConstantInt::get(GetCompareTy(LHS), 1);
2381 if (CmpInst::isFalseWhenEqual(Pred))
2382 return ConstantInt::get(GetCompareTy(LHS), 0);
2385 // Handle fcmp with constant RHS
2386 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
2387 // If the constant is a nan, see if we can fold the comparison based on it.
2388 if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHSC)) {
2389 if (CFP->getValueAPF().isNaN()) {
2390 if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo"
2391 return ConstantInt::getFalse(CFP->getContext());
2392 assert(FCmpInst::isUnordered(Pred) &&
2393 "Comparison must be either ordered or unordered!");
2394 // True if unordered.
2395 return ConstantInt::getTrue(CFP->getContext());
2397 // Check whether the constant is an infinity.
2398 if (CFP->getValueAPF().isInfinity()) {
2399 if (CFP->getValueAPF().isNegative()) {
2401 case FCmpInst::FCMP_OLT:
2402 // No value is ordered and less than negative infinity.
2403 return ConstantInt::getFalse(CFP->getContext());
2404 case FCmpInst::FCMP_UGE:
2405 // All values are unordered with or at least negative infinity.
2406 return ConstantInt::getTrue(CFP->getContext());
2412 case FCmpInst::FCMP_OGT:
2413 // No value is ordered and greater than infinity.
2414 return ConstantInt::getFalse(CFP->getContext());
2415 case FCmpInst::FCMP_ULE:
2416 // All values are unordered with and at most infinity.
2417 return ConstantInt::getTrue(CFP->getContext());
2426 // If the comparison is with the result of a select instruction, check whether
2427 // comparing with either branch of the select always yields the same value.
2428 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2429 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
2432 // If the comparison is with the result of a phi instruction, check whether
2433 // doing the compare with each incoming phi value yields a common result.
2434 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2435 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
2441 Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2442 const TargetData *TD,
2443 const TargetLibraryInfo *TLI,
2444 const DominatorTree *DT) {
2445 return ::SimplifyFCmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
2449 /// SimplifySelectInst - Given operands for a SelectInst, see if we can fold
2450 /// the result. If not, this returns null.
2451 static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal,
2452 Value *FalseVal, const Query &Q,
2453 unsigned MaxRecurse) {
2454 // select true, X, Y -> X
2455 // select false, X, Y -> Y
2456 if (ConstantInt *CB = dyn_cast<ConstantInt>(CondVal))
2457 return CB->getZExtValue() ? TrueVal : FalseVal;
2459 // select C, X, X -> X
2460 if (TrueVal == FalseVal)
2463 if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y
2464 if (isa<Constant>(TrueVal))
2468 if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X
2470 if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
2476 Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
2477 const TargetData *TD,
2478 const TargetLibraryInfo *TLI,
2479 const DominatorTree *DT) {
2480 return ::SimplifySelectInst(Cond, TrueVal, FalseVal, Query (TD, TLI, DT),
2484 /// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
2485 /// fold the result. If not, this returns null.
2486 static Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const Query &Q, unsigned) {
2487 // The type of the GEP pointer operand.
2488 PointerType *PtrTy = dyn_cast<PointerType>(Ops[0]->getType());
2489 // The GEP pointer operand is not a pointer, it's a vector of pointers.
2493 // getelementptr P -> P.
2494 if (Ops.size() == 1)
2497 if (isa<UndefValue>(Ops[0])) {
2498 // Compute the (pointer) type returned by the GEP instruction.
2499 Type *LastType = GetElementPtrInst::getIndexedType(PtrTy, Ops.slice(1));
2500 Type *GEPTy = PointerType::get(LastType, PtrTy->getAddressSpace());
2501 return UndefValue::get(GEPTy);
2504 if (Ops.size() == 2) {
2505 // getelementptr P, 0 -> P.
2506 if (ConstantInt *C = dyn_cast<ConstantInt>(Ops[1]))
2509 // getelementptr P, N -> P if P points to a type of zero size.
2511 Type *Ty = PtrTy->getElementType();
2512 if (Ty->isSized() && Q.TD->getTypeAllocSize(Ty) == 0)
2517 // Check to see if this is constant foldable.
2518 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
2519 if (!isa<Constant>(Ops[i]))
2522 return ConstantExpr::getGetElementPtr(cast<Constant>(Ops[0]), Ops.slice(1));
2525 Value *llvm::SimplifyGEPInst(ArrayRef<Value *> Ops, const TargetData *TD,
2526 const TargetLibraryInfo *TLI,
2527 const DominatorTree *DT) {
2528 return ::SimplifyGEPInst(Ops, Query (TD, TLI, DT), RecursionLimit);
2531 /// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we
2532 /// can fold the result. If not, this returns null.
2533 static Value *SimplifyInsertValueInst(Value *Agg, Value *Val,
2534 ArrayRef<unsigned> Idxs, const Query &Q,
2536 if (Constant *CAgg = dyn_cast<Constant>(Agg))
2537 if (Constant *CVal = dyn_cast<Constant>(Val))
2538 return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
2540 // insertvalue x, undef, n -> x
2541 if (match(Val, m_Undef()))
2544 // insertvalue x, (extractvalue y, n), n
2545 if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
2546 if (EV->getAggregateOperand()->getType() == Agg->getType() &&
2547 EV->getIndices() == Idxs) {
2548 // insertvalue undef, (extractvalue y, n), n -> y
2549 if (match(Agg, m_Undef()))
2550 return EV->getAggregateOperand();
2552 // insertvalue y, (extractvalue y, n), n -> y
2553 if (Agg == EV->getAggregateOperand())
2560 Value *llvm::SimplifyInsertValueInst(Value *Agg, Value *Val,
2561 ArrayRef<unsigned> Idxs,
2562 const TargetData *TD,
2563 const TargetLibraryInfo *TLI,
2564 const DominatorTree *DT) {
2565 return ::SimplifyInsertValueInst(Agg, Val, Idxs, Query (TD, TLI, DT),
2569 /// SimplifyPHINode - See if we can fold the given phi. If not, returns null.
2570 static Value *SimplifyPHINode(PHINode *PN, const Query &Q) {
2571 // If all of the PHI's incoming values are the same then replace the PHI node
2572 // with the common value.
2573 Value *CommonValue = 0;
2574 bool HasUndefInput = false;
2575 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
2576 Value *Incoming = PN->getIncomingValue(i);
2577 // If the incoming value is the phi node itself, it can safely be skipped.
2578 if (Incoming == PN) continue;
2579 if (isa<UndefValue>(Incoming)) {
2580 // Remember that we saw an undef value, but otherwise ignore them.
2581 HasUndefInput = true;
2584 if (CommonValue && Incoming != CommonValue)
2585 return 0; // Not the same, bail out.
2586 CommonValue = Incoming;
2589 // If CommonValue is null then all of the incoming values were either undef or
2590 // equal to the phi node itself.
2592 return UndefValue::get(PN->getType());
2594 // If we have a PHI node like phi(X, undef, X), where X is defined by some
2595 // instruction, we cannot return X as the result of the PHI node unless it
2596 // dominates the PHI block.
2598 return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : 0;
2603 static Value *SimplifyTruncInst(Value *Op, Type *Ty, const Query &Q, unsigned) {
2604 if (Constant *C = dyn_cast<Constant>(Op))
2605 return ConstantFoldInstOperands(Instruction::Trunc, Ty, C, Q.TD, Q.TLI);
2610 Value *llvm::SimplifyTruncInst(Value *Op, Type *Ty, const TargetData *TD,
2611 const TargetLibraryInfo *TLI,
2612 const DominatorTree *DT) {
2613 return ::SimplifyTruncInst(Op, Ty, Query (TD, TLI, DT), RecursionLimit);
2616 //=== Helper functions for higher up the class hierarchy.
2618 /// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
2619 /// fold the result. If not, this returns null.
2620 static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
2621 const Query &Q, unsigned MaxRecurse) {
2623 case Instruction::Add:
2624 return SimplifyAddInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2626 case Instruction::Sub:
2627 return SimplifySubInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2629 case Instruction::Mul: return SimplifyMulInst (LHS, RHS, Q, MaxRecurse);
2630 case Instruction::SDiv: return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
2631 case Instruction::UDiv: return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
2632 case Instruction::FDiv: return SimplifyFDivInst(LHS, RHS, Q, MaxRecurse);
2633 case Instruction::SRem: return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
2634 case Instruction::URem: return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
2635 case Instruction::FRem: return SimplifyFRemInst(LHS, RHS, Q, MaxRecurse);
2636 case Instruction::Shl:
2637 return SimplifyShlInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2639 case Instruction::LShr:
2640 return SimplifyLShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
2641 case Instruction::AShr:
2642 return SimplifyAShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
2643 case Instruction::And: return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
2644 case Instruction::Or: return SimplifyOrInst (LHS, RHS, Q, MaxRecurse);
2645 case Instruction::Xor: return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
2647 if (Constant *CLHS = dyn_cast<Constant>(LHS))
2648 if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
2649 Constant *COps[] = {CLHS, CRHS};
2650 return ConstantFoldInstOperands(Opcode, LHS->getType(), COps, Q.TD,
2654 // If the operation is associative, try some generic simplifications.
2655 if (Instruction::isAssociative(Opcode))
2656 if (Value *V = SimplifyAssociativeBinOp(Opcode, LHS, RHS, Q, MaxRecurse))
2659 // If the operation is with the result of a select instruction check whether
2660 // operating on either branch of the select always yields the same value.
2661 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2662 if (Value *V = ThreadBinOpOverSelect(Opcode, LHS, RHS, Q, MaxRecurse))
2665 // If the operation is with the result of a phi instruction, check whether
2666 // operating on all incoming values of the phi always yields the same value.
2667 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2668 if (Value *V = ThreadBinOpOverPHI(Opcode, LHS, RHS, Q, MaxRecurse))
2675 Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
2676 const TargetData *TD, const TargetLibraryInfo *TLI,
2677 const DominatorTree *DT) {
2678 return ::SimplifyBinOp(Opcode, LHS, RHS, Query (TD, TLI, DT), RecursionLimit);
2681 /// SimplifyCmpInst - Given operands for a CmpInst, see if we can
2682 /// fold the result.
2683 static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2684 const Query &Q, unsigned MaxRecurse) {
2685 if (CmpInst::isIntPredicate((CmpInst::Predicate)Predicate))
2686 return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
2687 return SimplifyFCmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
2690 Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2691 const TargetData *TD, const TargetLibraryInfo *TLI,
2692 const DominatorTree *DT) {
2693 return ::SimplifyCmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
2697 static Value *SimplifyCallInst(CallInst *CI, const Query &) {
2698 // call undef -> undef
2699 if (isa<UndefValue>(CI->getCalledValue()))
2700 return UndefValue::get(CI->getType());
2705 /// SimplifyInstruction - See if we can compute a simplified version of this
2706 /// instruction. If not, this returns null.
2707 Value *llvm::SimplifyInstruction(Instruction *I, const TargetData *TD,
2708 const TargetLibraryInfo *TLI,
2709 const DominatorTree *DT) {
2712 switch (I->getOpcode()) {
2714 Result = ConstantFoldInstruction(I, TD, TLI);
2716 case Instruction::Add:
2717 Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
2718 cast<BinaryOperator>(I)->hasNoSignedWrap(),
2719 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
2722 case Instruction::Sub:
2723 Result = SimplifySubInst(I->getOperand(0), I->getOperand(1),
2724 cast<BinaryOperator>(I)->hasNoSignedWrap(),
2725 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
2728 case Instruction::Mul:
2729 Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2731 case Instruction::SDiv:
2732 Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2734 case Instruction::UDiv:
2735 Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2737 case Instruction::FDiv:
2738 Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2740 case Instruction::SRem:
2741 Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2743 case Instruction::URem:
2744 Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2746 case Instruction::FRem:
2747 Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2749 case Instruction::Shl:
2750 Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1),
2751 cast<BinaryOperator>(I)->hasNoSignedWrap(),
2752 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
2755 case Instruction::LShr:
2756 Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
2757 cast<BinaryOperator>(I)->isExact(),
2760 case Instruction::AShr:
2761 Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
2762 cast<BinaryOperator>(I)->isExact(),
2765 case Instruction::And:
2766 Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2768 case Instruction::Or:
2769 Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2771 case Instruction::Xor:
2772 Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2774 case Instruction::ICmp:
2775 Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
2776 I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2778 case Instruction::FCmp:
2779 Result = SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(),
2780 I->getOperand(0), I->getOperand(1), TD, TLI, DT);
2782 case Instruction::Select:
2783 Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
2784 I->getOperand(2), TD, TLI, DT);
2786 case Instruction::GetElementPtr: {
2787 SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end());
2788 Result = SimplifyGEPInst(Ops, TD, TLI, DT);
2791 case Instruction::InsertValue: {
2792 InsertValueInst *IV = cast<InsertValueInst>(I);
2793 Result = SimplifyInsertValueInst(IV->getAggregateOperand(),
2794 IV->getInsertedValueOperand(),
2795 IV->getIndices(), TD, TLI, DT);
2798 case Instruction::PHI:
2799 Result = SimplifyPHINode(cast<PHINode>(I), Query (TD, TLI, DT));
2801 case Instruction::Call:
2802 Result = SimplifyCallInst(cast<CallInst>(I), Query (TD, TLI, DT));
2804 case Instruction::Trunc:
2805 Result = SimplifyTruncInst(I->getOperand(0), I->getType(), TD, TLI, DT);
2809 /// If called on unreachable code, the above logic may report that the
2810 /// instruction simplified to itself. Make life easier for users by
2811 /// detecting that case here, returning a safe value instead.
2812 return Result == I ? UndefValue::get(I->getType()) : Result;
2815 /// ReplaceAndSimplifyAllUses - Perform From->replaceAllUsesWith(To) and then
2816 /// delete the From instruction. In addition to a basic RAUW, this does a
2817 /// recursive simplification of the newly formed instructions. This catches
2818 /// things where one simplification exposes other opportunities. This only
2819 /// simplifies and deletes scalar operations, it does not change the CFG.
2821 void llvm::ReplaceAndSimplifyAllUses(Instruction *From, Value *To,
2822 const TargetData *TD,
2823 const TargetLibraryInfo *TLI,
2824 const DominatorTree *DT) {
2825 assert(From != To && "ReplaceAndSimplifyAllUses(X,X) is not valid!");
2827 // FromHandle/ToHandle - This keeps a WeakVH on the from/to values so that
2828 // we can know if it gets deleted out from under us or replaced in a
2829 // recursive simplification.
2830 WeakVH FromHandle(From);
2831 WeakVH ToHandle(To);
2833 while (!From->use_empty()) {
2834 // Update the instruction to use the new value.
2835 Use &TheUse = From->use_begin().getUse();
2836 Instruction *User = cast<Instruction>(TheUse.getUser());
2839 // Check to see if the instruction can be folded due to the operand
2840 // replacement. For example changing (or X, Y) into (or X, -1) can replace
2841 // the 'or' with -1.
2842 Value *SimplifiedVal;
2844 // Sanity check to make sure 'User' doesn't dangle across
2845 // SimplifyInstruction.
2846 AssertingVH<> UserHandle(User);
2848 SimplifiedVal = SimplifyInstruction(User, TD, TLI, DT);
2849 if (SimplifiedVal == 0) continue;
2852 // Recursively simplify this user to the new value.
2853 ReplaceAndSimplifyAllUses(User, SimplifiedVal, TD, TLI, DT);
2854 From = dyn_cast_or_null<Instruction>((Value*)FromHandle);
2857 assert(ToHandle && "To value deleted by recursive simplification?");
2859 // If the recursive simplification ended up revisiting and deleting
2860 // 'From' then we're done.
2865 // If 'From' has value handles referring to it, do a real RAUW to update them.
2866 From->replaceAllUsesWith(To);
2868 From->eraseFromParent();