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/Operator.h"
22 #include "llvm/ADT/Statistic.h"
23 #include "llvm/Analysis/InstructionSimplify.h"
24 #include "llvm/Analysis/ConstantFolding.h"
25 #include "llvm/Analysis/Dominators.h"
26 #include "llvm/Analysis/ValueTracking.h"
27 #include "llvm/Support/ConstantRange.h"
28 #include "llvm/Support/PatternMatch.h"
29 #include "llvm/Support/ValueHandle.h"
30 #include "llvm/Target/TargetData.h"
32 using namespace llvm::PatternMatch;
34 enum { RecursionLimit = 3 };
36 STATISTIC(NumExpand, "Number of expansions");
37 STATISTIC(NumFactor , "Number of factorizations");
38 STATISTIC(NumReassoc, "Number of reassociations");
40 static Value *SimplifyAndInst(Value *, Value *, const TargetData *,
41 const DominatorTree *, unsigned);
42 static Value *SimplifyBinOp(unsigned, Value *, Value *, const TargetData *,
43 const DominatorTree *, unsigned);
44 static Value *SimplifyCmpInst(unsigned, Value *, Value *, const TargetData *,
45 const DominatorTree *, unsigned);
46 static Value *SimplifyOrInst(Value *, Value *, const TargetData *,
47 const DominatorTree *, unsigned);
48 static Value *SimplifyXorInst(Value *, Value *, const TargetData *,
49 const DominatorTree *, unsigned);
51 /// getFalse - For a boolean type, or a vector of boolean type, return false, or
52 /// a vector with every element false, as appropriate for the type.
53 static Constant *getFalse(Type *Ty) {
54 assert((Ty->isIntegerTy(1) ||
56 cast<VectorType>(Ty)->getElementType()->isIntegerTy(1))) &&
57 "Expected i1 type or a vector of i1!");
58 return Constant::getNullValue(Ty);
61 /// getTrue - For a boolean type, or a vector of boolean type, return true, or
62 /// a vector with every element true, as appropriate for the type.
63 static Constant *getTrue(Type *Ty) {
64 assert((Ty->isIntegerTy(1) ||
66 cast<VectorType>(Ty)->getElementType()->isIntegerTy(1))) &&
67 "Expected i1 type or a vector of i1!");
68 return Constant::getAllOnesValue(Ty);
71 /// ValueDominatesPHI - Does the given value dominate the specified phi node?
72 static bool ValueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
73 Instruction *I = dyn_cast<Instruction>(V);
75 // Arguments and constants dominate all instructions.
78 // If we have a DominatorTree then do a precise test.
80 return DT->dominates(I, P);
82 // Otherwise, if the instruction is in the entry block, and is not an invoke,
83 // then it obviously dominates all phi nodes.
84 if (I->getParent() == &I->getParent()->getParent()->getEntryBlock() &&
91 /// ExpandBinOp - Simplify "A op (B op' C)" by distributing op over op', turning
92 /// it into "(A op B) op' (A op C)". Here "op" is given by Opcode and "op'" is
93 /// given by OpcodeToExpand, while "A" corresponds to LHS and "B op' C" to RHS.
94 /// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)".
95 /// Returns the simplified value, or null if no simplification was performed.
96 static Value *ExpandBinOp(unsigned Opcode, Value *LHS, Value *RHS,
97 unsigned OpcToExpand, const TargetData *TD,
98 const DominatorTree *DT, unsigned MaxRecurse) {
99 Instruction::BinaryOps OpcodeToExpand = (Instruction::BinaryOps)OpcToExpand;
100 // Recursion is always used, so bail out at once if we already hit the limit.
104 // Check whether the expression has the form "(A op' B) op C".
105 if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS))
106 if (Op0->getOpcode() == OpcodeToExpand) {
107 // It does! Try turning it into "(A op C) op' (B op C)".
108 Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS;
109 // Do "A op C" and "B op C" both simplify?
110 if (Value *L = SimplifyBinOp(Opcode, A, C, TD, DT, MaxRecurse))
111 if (Value *R = SimplifyBinOp(Opcode, B, C, TD, DT, MaxRecurse)) {
112 // They do! Return "L op' R" if it simplifies or is already available.
113 // If "L op' R" equals "A op' B" then "L op' R" is just the LHS.
114 if ((L == A && R == B) || (Instruction::isCommutative(OpcodeToExpand)
115 && L == B && R == A)) {
119 // Otherwise return "L op' R" if it simplifies.
120 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, TD, DT,
128 // Check whether the expression has the form "A op (B op' C)".
129 if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS))
130 if (Op1->getOpcode() == OpcodeToExpand) {
131 // It does! Try turning it into "(A op B) op' (A op C)".
132 Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1);
133 // Do "A op B" and "A op C" both simplify?
134 if (Value *L = SimplifyBinOp(Opcode, A, B, TD, DT, MaxRecurse))
135 if (Value *R = SimplifyBinOp(Opcode, A, C, TD, DT, MaxRecurse)) {
136 // They do! Return "L op' R" if it simplifies or is already available.
137 // If "L op' R" equals "B op' C" then "L op' R" is just the RHS.
138 if ((L == B && R == C) || (Instruction::isCommutative(OpcodeToExpand)
139 && L == C && R == B)) {
143 // Otherwise return "L op' R" if it simplifies.
144 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, TD, DT,
155 /// FactorizeBinOp - Simplify "LHS Opcode RHS" by factorizing out a common term
156 /// using the operation OpCodeToExtract. For example, when Opcode is Add and
157 /// OpCodeToExtract is Mul then this tries to turn "(A*B)+(A*C)" into "A*(B+C)".
158 /// Returns the simplified value, or null if no simplification was performed.
159 static Value *FactorizeBinOp(unsigned Opcode, Value *LHS, Value *RHS,
160 unsigned OpcToExtract, const TargetData *TD,
161 const DominatorTree *DT, unsigned MaxRecurse) {
162 Instruction::BinaryOps OpcodeToExtract = (Instruction::BinaryOps)OpcToExtract;
163 // Recursion is always used, so bail out at once if we already hit the limit.
167 BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
168 BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
170 if (!Op0 || Op0->getOpcode() != OpcodeToExtract ||
171 !Op1 || Op1->getOpcode() != OpcodeToExtract)
174 // The expression has the form "(A op' B) op (C op' D)".
175 Value *A = Op0->getOperand(0), *B = Op0->getOperand(1);
176 Value *C = Op1->getOperand(0), *D = Op1->getOperand(1);
178 // Use left distributivity, i.e. "X op' (Y op Z) = (X op' Y) op (X op' Z)".
179 // Does the instruction have the form "(A op' B) op (A op' D)" or, in the
180 // commutative case, "(A op' B) op (C op' A)"?
181 if (A == C || (Instruction::isCommutative(OpcodeToExtract) && A == D)) {
182 Value *DD = A == C ? D : C;
183 // Form "A op' (B op DD)" if it simplifies completely.
184 // Does "B op DD" simplify?
185 if (Value *V = SimplifyBinOp(Opcode, B, DD, TD, DT, MaxRecurse)) {
186 // It does! Return "A op' V" if it simplifies or is already available.
187 // If V equals B then "A op' V" is just the LHS. If V equals DD then
188 // "A op' V" is just the RHS.
189 if (V == B || V == DD) {
191 return V == B ? LHS : RHS;
193 // Otherwise return "A op' V" if it simplifies.
194 if (Value *W = SimplifyBinOp(OpcodeToExtract, A, V, TD, DT, MaxRecurse)) {
201 // Use right distributivity, i.e. "(X op Y) op' Z = (X op' Z) op (Y op' Z)".
202 // Does the instruction have the form "(A op' B) op (C op' B)" or, in the
203 // commutative case, "(A op' B) op (B op' D)"?
204 if (B == D || (Instruction::isCommutative(OpcodeToExtract) && B == C)) {
205 Value *CC = B == D ? C : D;
206 // Form "(A op CC) op' B" if it simplifies completely..
207 // Does "A op CC" simplify?
208 if (Value *V = SimplifyBinOp(Opcode, A, CC, TD, DT, MaxRecurse)) {
209 // It does! Return "V op' B" if it simplifies or is already available.
210 // If V equals A then "V op' B" is just the LHS. If V equals CC then
211 // "V op' B" is just the RHS.
212 if (V == A || V == CC) {
214 return V == A ? LHS : RHS;
216 // Otherwise return "V op' B" if it simplifies.
217 if (Value *W = SimplifyBinOp(OpcodeToExtract, V, B, TD, DT, MaxRecurse)) {
227 /// SimplifyAssociativeBinOp - Generic simplifications for associative binary
228 /// operations. Returns the simpler value, or null if none was found.
229 static Value *SimplifyAssociativeBinOp(unsigned Opc, Value *LHS, Value *RHS,
230 const TargetData *TD,
231 const DominatorTree *DT,
232 unsigned MaxRecurse) {
233 Instruction::BinaryOps Opcode = (Instruction::BinaryOps)Opc;
234 assert(Instruction::isAssociative(Opcode) && "Not an associative operation!");
236 // Recursion is always used, so bail out at once if we already hit the limit.
240 BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
241 BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
243 // Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely.
244 if (Op0 && Op0->getOpcode() == Opcode) {
245 Value *A = Op0->getOperand(0);
246 Value *B = Op0->getOperand(1);
249 // Does "B op C" simplify?
250 if (Value *V = SimplifyBinOp(Opcode, B, C, TD, DT, MaxRecurse)) {
251 // It does! Return "A op V" if it simplifies or is already available.
252 // If V equals B then "A op V" is just the LHS.
253 if (V == B) return LHS;
254 // Otherwise return "A op V" if it simplifies.
255 if (Value *W = SimplifyBinOp(Opcode, A, V, TD, DT, MaxRecurse)) {
262 // Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely.
263 if (Op1 && Op1->getOpcode() == Opcode) {
265 Value *B = Op1->getOperand(0);
266 Value *C = Op1->getOperand(1);
268 // Does "A op B" simplify?
269 if (Value *V = SimplifyBinOp(Opcode, A, B, TD, DT, MaxRecurse)) {
270 // It does! Return "V op C" if it simplifies or is already available.
271 // If V equals B then "V op C" is just the RHS.
272 if (V == B) return RHS;
273 // Otherwise return "V op C" if it simplifies.
274 if (Value *W = SimplifyBinOp(Opcode, V, C, TD, DT, MaxRecurse)) {
281 // The remaining transforms require commutativity as well as associativity.
282 if (!Instruction::isCommutative(Opcode))
285 // Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely.
286 if (Op0 && Op0->getOpcode() == Opcode) {
287 Value *A = Op0->getOperand(0);
288 Value *B = Op0->getOperand(1);
291 // Does "C op A" simplify?
292 if (Value *V = SimplifyBinOp(Opcode, C, A, TD, DT, MaxRecurse)) {
293 // It does! Return "V op B" if it simplifies or is already available.
294 // If V equals A then "V op B" is just the LHS.
295 if (V == A) return LHS;
296 // Otherwise return "V op B" if it simplifies.
297 if (Value *W = SimplifyBinOp(Opcode, V, B, TD, DT, MaxRecurse)) {
304 // Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely.
305 if (Op1 && Op1->getOpcode() == Opcode) {
307 Value *B = Op1->getOperand(0);
308 Value *C = Op1->getOperand(1);
310 // Does "C op A" simplify?
311 if (Value *V = SimplifyBinOp(Opcode, C, A, TD, DT, MaxRecurse)) {
312 // It does! Return "B op V" if it simplifies or is already available.
313 // If V equals C then "B op V" is just the RHS.
314 if (V == C) return RHS;
315 // Otherwise return "B op V" if it simplifies.
316 if (Value *W = SimplifyBinOp(Opcode, B, V, TD, DT, MaxRecurse)) {
326 /// ThreadBinOpOverSelect - In the case of a binary operation with a select
327 /// instruction as an operand, try to simplify the binop by seeing whether
328 /// evaluating it on both branches of the select results in the same value.
329 /// Returns the common value if so, otherwise returns null.
330 static Value *ThreadBinOpOverSelect(unsigned Opcode, Value *LHS, Value *RHS,
331 const TargetData *TD,
332 const DominatorTree *DT,
333 unsigned MaxRecurse) {
334 // Recursion is always used, so bail out at once if we already hit the limit.
339 if (isa<SelectInst>(LHS)) {
340 SI = cast<SelectInst>(LHS);
342 assert(isa<SelectInst>(RHS) && "No select instruction operand!");
343 SI = cast<SelectInst>(RHS);
346 // Evaluate the BinOp on the true and false branches of the select.
350 TV = SimplifyBinOp(Opcode, SI->getTrueValue(), RHS, TD, DT, MaxRecurse);
351 FV = SimplifyBinOp(Opcode, SI->getFalseValue(), RHS, TD, DT, MaxRecurse);
353 TV = SimplifyBinOp(Opcode, LHS, SI->getTrueValue(), TD, DT, MaxRecurse);
354 FV = SimplifyBinOp(Opcode, LHS, SI->getFalseValue(), TD, DT, MaxRecurse);
357 // If they simplified to the same value, then return the common value.
358 // If they both failed to simplify then return null.
362 // If one branch simplified to undef, return the other one.
363 if (TV && isa<UndefValue>(TV))
365 if (FV && isa<UndefValue>(FV))
368 // If applying the operation did not change the true and false select values,
369 // then the result of the binop is the select itself.
370 if (TV == SI->getTrueValue() && FV == SI->getFalseValue())
373 // If one branch simplified and the other did not, and the simplified
374 // value is equal to the unsimplified one, return the simplified value.
375 // For example, select (cond, X, X & Z) & Z -> X & Z.
376 if ((FV && !TV) || (TV && !FV)) {
377 // Check that the simplified value has the form "X op Y" where "op" is the
378 // same as the original operation.
379 Instruction *Simplified = dyn_cast<Instruction>(FV ? FV : TV);
380 if (Simplified && Simplified->getOpcode() == Opcode) {
381 // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS".
382 // We already know that "op" is the same as for the simplified value. See
383 // if the operands match too. If so, return the simplified value.
384 Value *UnsimplifiedBranch = FV ? SI->getTrueValue() : SI->getFalseValue();
385 Value *UnsimplifiedLHS = SI == LHS ? UnsimplifiedBranch : LHS;
386 Value *UnsimplifiedRHS = SI == LHS ? RHS : UnsimplifiedBranch;
387 if (Simplified->getOperand(0) == UnsimplifiedLHS &&
388 Simplified->getOperand(1) == UnsimplifiedRHS)
390 if (Simplified->isCommutative() &&
391 Simplified->getOperand(1) == UnsimplifiedLHS &&
392 Simplified->getOperand(0) == UnsimplifiedRHS)
400 /// ThreadCmpOverSelect - In the case of a comparison with a select instruction,
401 /// try to simplify the comparison by seeing whether both branches of the select
402 /// result in the same value. Returns the common value if so, otherwise returns
404 static Value *ThreadCmpOverSelect(CmpInst::Predicate Pred, Value *LHS,
405 Value *RHS, const TargetData *TD,
406 const DominatorTree *DT,
407 unsigned MaxRecurse) {
408 // Recursion is always used, so bail out at once if we already hit the limit.
412 // Make sure the select is on the LHS.
413 if (!isa<SelectInst>(LHS)) {
415 Pred = CmpInst::getSwappedPredicate(Pred);
417 assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!");
418 SelectInst *SI = cast<SelectInst>(LHS);
420 // Now that we have "cmp select(Cond, TV, FV), RHS", analyse it.
421 // Does "cmp TV, RHS" simplify?
422 if (Value *TCmp = SimplifyCmpInst(Pred, SI->getTrueValue(), RHS, TD, DT,
424 // It does! Does "cmp FV, RHS" simplify?
425 if (Value *FCmp = SimplifyCmpInst(Pred, SI->getFalseValue(), RHS, TD, DT,
427 // It does! If they simplified to the same value, then use it as the
428 // result of the original comparison.
431 Value *Cond = SI->getCondition();
432 // If the false value simplified to false, then the result of the compare
433 // is equal to "Cond && TCmp". This also catches the case when the false
434 // value simplified to false and the true value to true, returning "Cond".
435 if (match(FCmp, m_Zero()))
436 if (Value *V = SimplifyAndInst(Cond, TCmp, TD, DT, MaxRecurse))
438 // If the true value simplified to true, then the result of the compare
439 // is equal to "Cond || FCmp".
440 if (match(TCmp, m_One()))
441 if (Value *V = SimplifyOrInst(Cond, FCmp, TD, DT, MaxRecurse))
443 // Finally, if the false value simplified to true and the true value to
444 // false, then the result of the compare is equal to "!Cond".
445 if (match(FCmp, m_One()) && match(TCmp, m_Zero()))
447 SimplifyXorInst(Cond, Constant::getAllOnesValue(Cond->getType()),
456 /// ThreadBinOpOverPHI - In the case of a binary operation with an operand that
457 /// is a PHI instruction, try to simplify the binop by seeing whether evaluating
458 /// it on the incoming phi values yields the same result for every value. If so
459 /// returns the common value, otherwise returns null.
460 static Value *ThreadBinOpOverPHI(unsigned Opcode, Value *LHS, Value *RHS,
461 const TargetData *TD, const DominatorTree *DT,
462 unsigned MaxRecurse) {
463 // Recursion is always used, so bail out at once if we already hit the limit.
468 if (isa<PHINode>(LHS)) {
469 PI = cast<PHINode>(LHS);
470 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
471 if (!ValueDominatesPHI(RHS, PI, DT))
474 assert(isa<PHINode>(RHS) && "No PHI instruction operand!");
475 PI = cast<PHINode>(RHS);
476 // Bail out if LHS and the phi may be mutually interdependent due to a loop.
477 if (!ValueDominatesPHI(LHS, PI, DT))
481 // Evaluate the BinOp on the incoming phi values.
482 Value *CommonValue = 0;
483 for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
484 Value *Incoming = PI->getIncomingValue(i);
485 // If the incoming value is the phi node itself, it can safely be skipped.
486 if (Incoming == PI) continue;
487 Value *V = PI == LHS ?
488 SimplifyBinOp(Opcode, Incoming, RHS, TD, DT, MaxRecurse) :
489 SimplifyBinOp(Opcode, LHS, Incoming, TD, DT, MaxRecurse);
490 // If the operation failed to simplify, or simplified to a different value
491 // to previously, then give up.
492 if (!V || (CommonValue && V != CommonValue))
500 /// ThreadCmpOverPHI - In the case of a comparison with a PHI instruction, try
501 /// try to simplify the comparison by seeing whether comparing with all of the
502 /// incoming phi values yields the same result every time. If so returns the
503 /// common result, otherwise returns null.
504 static Value *ThreadCmpOverPHI(CmpInst::Predicate Pred, Value *LHS, Value *RHS,
505 const TargetData *TD, const DominatorTree *DT,
506 unsigned MaxRecurse) {
507 // Recursion is always used, so bail out at once if we already hit the limit.
511 // Make sure the phi is on the LHS.
512 if (!isa<PHINode>(LHS)) {
514 Pred = CmpInst::getSwappedPredicate(Pred);
516 assert(isa<PHINode>(LHS) && "Not comparing with a phi instruction!");
517 PHINode *PI = cast<PHINode>(LHS);
519 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
520 if (!ValueDominatesPHI(RHS, PI, DT))
523 // Evaluate the BinOp on the incoming phi values.
524 Value *CommonValue = 0;
525 for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
526 Value *Incoming = PI->getIncomingValue(i);
527 // If the incoming value is the phi node itself, it can safely be skipped.
528 if (Incoming == PI) continue;
529 Value *V = SimplifyCmpInst(Pred, Incoming, RHS, TD, DT, MaxRecurse);
530 // If the operation failed to simplify, or simplified to a different value
531 // to previously, then give up.
532 if (!V || (CommonValue && V != CommonValue))
540 /// SimplifyAddInst - Given operands for an Add, see if we can
541 /// fold the result. If not, this returns null.
542 static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
543 const TargetData *TD, const DominatorTree *DT,
544 unsigned MaxRecurse) {
545 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
546 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
547 Constant *Ops[] = { CLHS, CRHS };
548 return ConstantFoldInstOperands(Instruction::Add, CLHS->getType(),
552 // Canonicalize the constant to the RHS.
556 // X + undef -> undef
557 if (match(Op1, m_Undef()))
561 if (match(Op1, m_Zero()))
568 if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) ||
569 match(Op0, m_Sub(m_Value(Y), m_Specific(Op1))))
572 // X + ~X -> -1 since ~X = -X-1
573 if (match(Op0, m_Not(m_Specific(Op1))) ||
574 match(Op1, m_Not(m_Specific(Op0))))
575 return Constant::getAllOnesValue(Op0->getType());
578 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
579 if (Value *V = SimplifyXorInst(Op0, Op1, TD, DT, MaxRecurse-1))
582 // Try some generic simplifications for associative operations.
583 if (Value *V = SimplifyAssociativeBinOp(Instruction::Add, Op0, Op1, TD, DT,
587 // Mul distributes over Add. Try some generic simplifications based on this.
588 if (Value *V = FactorizeBinOp(Instruction::Add, Op0, Op1, Instruction::Mul,
592 // Threading Add over selects and phi nodes is pointless, so don't bother.
593 // Threading over the select in "A + select(cond, B, C)" means evaluating
594 // "A+B" and "A+C" and seeing if they are equal; but they are equal if and
595 // only if B and C are equal. If B and C are equal then (since we assume
596 // that operands have already been simplified) "select(cond, B, C)" should
597 // have been simplified to the common value of B and C already. Analysing
598 // "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly
599 // for threading over phi nodes.
604 Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
605 const TargetData *TD, const DominatorTree *DT) {
606 return ::SimplifyAddInst(Op0, Op1, isNSW, isNUW, TD, DT, RecursionLimit);
609 /// SimplifySubInst - Given operands for a Sub, see if we can
610 /// fold the result. If not, this returns null.
611 static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
612 const TargetData *TD, const DominatorTree *DT,
613 unsigned MaxRecurse) {
614 if (Constant *CLHS = dyn_cast<Constant>(Op0))
615 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
616 Constant *Ops[] = { CLHS, CRHS };
617 return ConstantFoldInstOperands(Instruction::Sub, CLHS->getType(),
621 // X - undef -> undef
622 // undef - X -> undef
623 if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
624 return UndefValue::get(Op0->getType());
627 if (match(Op1, m_Zero()))
632 return Constant::getNullValue(Op0->getType());
637 if (match(Op0, m_Mul(m_Specific(Op1), m_ConstantInt<2>())) ||
638 match(Op0, m_Shl(m_Specific(Op1), m_One())))
641 // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
642 // For example, (X + Y) - Y -> X; (Y + X) - Y -> X
643 Value *Y = 0, *Z = Op1;
644 if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z
645 // See if "V === Y - Z" simplifies.
646 if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, TD, DT, MaxRecurse-1))
647 // It does! Now see if "X + V" simplifies.
648 if (Value *W = SimplifyBinOp(Instruction::Add, X, V, TD, DT,
650 // It does, we successfully reassociated!
654 // See if "V === X - Z" simplifies.
655 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, TD, DT, MaxRecurse-1))
656 // It does! Now see if "Y + V" simplifies.
657 if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, TD, DT,
659 // It does, we successfully reassociated!
665 // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
666 // For example, X - (X + 1) -> -1
668 if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z)
669 // See if "V === X - Y" simplifies.
670 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, TD, DT, MaxRecurse-1))
671 // It does! Now see if "V - Z" simplifies.
672 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, TD, DT,
674 // It does, we successfully reassociated!
678 // See if "V === X - Z" simplifies.
679 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, TD, DT, MaxRecurse-1))
680 // It does! Now see if "V - Y" simplifies.
681 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, TD, DT,
683 // It does, we successfully reassociated!
689 // Z - (X - Y) -> (Z - X) + Y if everything simplifies.
690 // For example, X - (X - Y) -> Y.
692 if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y)
693 // See if "V === Z - X" simplifies.
694 if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, TD, DT, MaxRecurse-1))
695 // It does! Now see if "V + Y" simplifies.
696 if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, TD, DT,
698 // It does, we successfully reassociated!
703 // Mul distributes over Sub. Try some generic simplifications based on this.
704 if (Value *V = FactorizeBinOp(Instruction::Sub, Op0, Op1, Instruction::Mul,
709 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
710 if (Value *V = SimplifyXorInst(Op0, Op1, TD, DT, MaxRecurse-1))
713 // Threading Sub over selects and phi nodes is pointless, so don't bother.
714 // Threading over the select in "A - select(cond, B, C)" means evaluating
715 // "A-B" and "A-C" and seeing if they are equal; but they are equal if and
716 // only if B and C are equal. If B and C are equal then (since we assume
717 // that operands have already been simplified) "select(cond, B, C)" should
718 // have been simplified to the common value of B and C already. Analysing
719 // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly
720 // for threading over phi nodes.
725 Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
726 const TargetData *TD, const DominatorTree *DT) {
727 return ::SimplifySubInst(Op0, Op1, isNSW, isNUW, TD, DT, RecursionLimit);
730 /// SimplifyMulInst - Given operands for a Mul, see if we can
731 /// fold the result. If not, this returns null.
732 static Value *SimplifyMulInst(Value *Op0, Value *Op1, const TargetData *TD,
733 const DominatorTree *DT, unsigned MaxRecurse) {
734 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
735 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
736 Constant *Ops[] = { CLHS, CRHS };
737 return ConstantFoldInstOperands(Instruction::Mul, CLHS->getType(),
741 // Canonicalize the constant to the RHS.
746 if (match(Op1, m_Undef()))
747 return Constant::getNullValue(Op0->getType());
750 if (match(Op1, m_Zero()))
754 if (match(Op1, m_One()))
757 // (X / Y) * Y -> X if the division is exact.
758 Value *X = 0, *Y = 0;
759 if ((match(Op0, m_IDiv(m_Value(X), m_Value(Y))) && Y == Op1) || // (X / Y) * Y
760 (match(Op1, m_IDiv(m_Value(X), m_Value(Y))) && Y == Op0)) { // Y * (X / Y)
761 PossiblyExactOperator *Div =
762 cast<PossiblyExactOperator>(Y == Op1 ? Op0 : Op1);
768 if (MaxRecurse && Op0->getType()->isIntegerTy(1))
769 if (Value *V = SimplifyAndInst(Op0, Op1, TD, DT, MaxRecurse-1))
772 // Try some generic simplifications for associative operations.
773 if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, TD, DT,
777 // Mul distributes over Add. Try some generic simplifications based on this.
778 if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add,
782 // If the operation is with the result of a select instruction, check whether
783 // operating on either branch of the select always yields the same value.
784 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
785 if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, TD, DT,
789 // If the operation is with the result of a phi instruction, check whether
790 // operating on all incoming values of the phi always yields the same value.
791 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
792 if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, TD, DT,
799 Value *llvm::SimplifyMulInst(Value *Op0, Value *Op1, const TargetData *TD,
800 const DominatorTree *DT) {
801 return ::SimplifyMulInst(Op0, Op1, TD, DT, RecursionLimit);
804 /// SimplifyDiv - Given operands for an SDiv or UDiv, see if we can
805 /// fold the result. If not, this returns null.
806 static Value *SimplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
807 const TargetData *TD, const DominatorTree *DT,
808 unsigned MaxRecurse) {
809 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
810 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
811 Constant *Ops[] = { C0, C1 };
812 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, TD);
816 bool isSigned = Opcode == Instruction::SDiv;
818 // X / undef -> undef
819 if (match(Op1, m_Undef()))
823 if (match(Op0, m_Undef()))
824 return Constant::getNullValue(Op0->getType());
826 // 0 / X -> 0, we don't need to preserve faults!
827 if (match(Op0, m_Zero()))
831 if (match(Op1, m_One()))
834 if (Op0->getType()->isIntegerTy(1))
835 // It can't be division by zero, hence it must be division by one.
840 return ConstantInt::get(Op0->getType(), 1);
842 // (X * Y) / Y -> X if the multiplication does not overflow.
843 Value *X = 0, *Y = 0;
844 if (match(Op0, m_Mul(m_Value(X), m_Value(Y))) && (X == Op1 || Y == Op1)) {
845 if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1
846 OverflowingBinaryOperator *Mul = cast<OverflowingBinaryOperator>(Op0);
847 // If the Mul knows it does not overflow, then we are good to go.
848 if ((isSigned && Mul->hasNoSignedWrap()) ||
849 (!isSigned && Mul->hasNoUnsignedWrap()))
851 // If X has the form X = A / Y then X * Y cannot overflow.
852 if (BinaryOperator *Div = dyn_cast<BinaryOperator>(X))
853 if (Div->getOpcode() == Opcode && Div->getOperand(1) == Y)
857 // (X rem Y) / Y -> 0
858 if ((isSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
859 (!isSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
860 return Constant::getNullValue(Op0->getType());
862 // If the operation is with the result of a select instruction, check whether
863 // operating on either branch of the select always yields the same value.
864 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
865 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, TD, DT, MaxRecurse))
868 // If the operation is with the result of a phi instruction, check whether
869 // operating on all incoming values of the phi always yields the same value.
870 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
871 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, TD, DT, MaxRecurse))
877 /// SimplifySDivInst - Given operands for an SDiv, see if we can
878 /// fold the result. If not, this returns null.
879 static Value *SimplifySDivInst(Value *Op0, Value *Op1, const TargetData *TD,
880 const DominatorTree *DT, unsigned MaxRecurse) {
881 if (Value *V = SimplifyDiv(Instruction::SDiv, Op0, Op1, TD, DT, MaxRecurse))
887 Value *llvm::SimplifySDivInst(Value *Op0, Value *Op1, const TargetData *TD,
888 const DominatorTree *DT) {
889 return ::SimplifySDivInst(Op0, Op1, TD, DT, RecursionLimit);
892 /// SimplifyUDivInst - Given operands for a UDiv, see if we can
893 /// fold the result. If not, this returns null.
894 static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const TargetData *TD,
895 const DominatorTree *DT, unsigned MaxRecurse) {
896 if (Value *V = SimplifyDiv(Instruction::UDiv, Op0, Op1, TD, DT, MaxRecurse))
902 Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const TargetData *TD,
903 const DominatorTree *DT) {
904 return ::SimplifyUDivInst(Op0, Op1, TD, DT, RecursionLimit);
907 static Value *SimplifyFDivInst(Value *Op0, Value *Op1, const TargetData *,
908 const DominatorTree *, unsigned) {
909 // undef / X -> undef (the undef could be a snan).
910 if (match(Op0, m_Undef()))
913 // X / undef -> undef
914 if (match(Op1, m_Undef()))
920 Value *llvm::SimplifyFDivInst(Value *Op0, Value *Op1, const TargetData *TD,
921 const DominatorTree *DT) {
922 return ::SimplifyFDivInst(Op0, Op1, TD, DT, RecursionLimit);
925 /// SimplifyRem - Given operands for an SRem or URem, see if we can
926 /// fold the result. If not, this returns null.
927 static Value *SimplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
928 const TargetData *TD, const DominatorTree *DT,
929 unsigned MaxRecurse) {
930 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
931 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
932 Constant *Ops[] = { C0, C1 };
933 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, TD);
937 // X % undef -> undef
938 if (match(Op1, m_Undef()))
942 if (match(Op0, m_Undef()))
943 return Constant::getNullValue(Op0->getType());
945 // 0 % X -> 0, we don't need to preserve faults!
946 if (match(Op0, m_Zero()))
949 // X % 0 -> undef, we don't need to preserve faults!
950 if (match(Op1, m_Zero()))
951 return UndefValue::get(Op0->getType());
954 if (match(Op1, m_One()))
955 return Constant::getNullValue(Op0->getType());
957 if (Op0->getType()->isIntegerTy(1))
958 // It can't be remainder by zero, hence it must be remainder by one.
959 return Constant::getNullValue(Op0->getType());
963 return Constant::getNullValue(Op0->getType());
965 // If the operation is with the result of a select instruction, check whether
966 // operating on either branch of the select always yields the same value.
967 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
968 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, TD, DT, MaxRecurse))
971 // If the operation is with the result of a phi instruction, check whether
972 // operating on all incoming values of the phi always yields the same value.
973 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
974 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, TD, DT, MaxRecurse))
980 /// SimplifySRemInst - Given operands for an SRem, see if we can
981 /// fold the result. If not, this returns null.
982 static Value *SimplifySRemInst(Value *Op0, Value *Op1, const TargetData *TD,
983 const DominatorTree *DT, unsigned MaxRecurse) {
984 if (Value *V = SimplifyRem(Instruction::SRem, Op0, Op1, TD, DT, MaxRecurse))
990 Value *llvm::SimplifySRemInst(Value *Op0, Value *Op1, const TargetData *TD,
991 const DominatorTree *DT) {
992 return ::SimplifySRemInst(Op0, Op1, TD, DT, RecursionLimit);
995 /// SimplifyURemInst - Given operands for a URem, see if we can
996 /// fold the result. If not, this returns null.
997 static Value *SimplifyURemInst(Value *Op0, Value *Op1, const TargetData *TD,
998 const DominatorTree *DT, unsigned MaxRecurse) {
999 if (Value *V = SimplifyRem(Instruction::URem, Op0, Op1, TD, DT, MaxRecurse))
1005 Value *llvm::SimplifyURemInst(Value *Op0, Value *Op1, const TargetData *TD,
1006 const DominatorTree *DT) {
1007 return ::SimplifyURemInst(Op0, Op1, TD, DT, RecursionLimit);
1010 static Value *SimplifyFRemInst(Value *Op0, Value *Op1, const TargetData *,
1011 const DominatorTree *, unsigned) {
1012 // undef % X -> undef (the undef could be a snan).
1013 if (match(Op0, m_Undef()))
1016 // X % undef -> undef
1017 if (match(Op1, m_Undef()))
1023 Value *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, const TargetData *TD,
1024 const DominatorTree *DT) {
1025 return ::SimplifyFRemInst(Op0, Op1, TD, DT, RecursionLimit);
1028 /// SimplifyShift - Given operands for an Shl, LShr or AShr, see if we can
1029 /// fold the result. If not, this returns null.
1030 static Value *SimplifyShift(unsigned Opcode, Value *Op0, Value *Op1,
1031 const TargetData *TD, const DominatorTree *DT,
1032 unsigned MaxRecurse) {
1033 if (Constant *C0 = dyn_cast<Constant>(Op0)) {
1034 if (Constant *C1 = dyn_cast<Constant>(Op1)) {
1035 Constant *Ops[] = { C0, C1 };
1036 return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, TD);
1040 // 0 shift by X -> 0
1041 if (match(Op0, m_Zero()))
1044 // X shift by 0 -> X
1045 if (match(Op1, m_Zero()))
1048 // X shift by undef -> undef because it may shift by the bitwidth.
1049 if (match(Op1, m_Undef()))
1052 // Shifting by the bitwidth or more is undefined.
1053 if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1))
1054 if (CI->getValue().getLimitedValue() >=
1055 Op0->getType()->getScalarSizeInBits())
1056 return UndefValue::get(Op0->getType());
1058 // If the operation is with the result of a select instruction, check whether
1059 // operating on either branch of the select always yields the same value.
1060 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1061 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, TD, DT, MaxRecurse))
1064 // If the operation is with the result of a phi instruction, check whether
1065 // operating on all incoming values of the phi always yields the same value.
1066 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1067 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, TD, DT, MaxRecurse))
1073 /// SimplifyShlInst - Given operands for an Shl, see if we can
1074 /// fold the result. If not, this returns null.
1075 static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1076 const TargetData *TD, const DominatorTree *DT,
1077 unsigned MaxRecurse) {
1078 if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, TD, DT, MaxRecurse))
1082 if (match(Op0, m_Undef()))
1083 return Constant::getNullValue(Op0->getType());
1085 // (X >> A) << A -> X
1087 if (match(Op0, m_Shr(m_Value(X), m_Specific(Op1))) &&
1088 cast<PossiblyExactOperator>(Op0)->isExact())
1093 Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1094 const TargetData *TD, const DominatorTree *DT) {
1095 return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, TD, DT, RecursionLimit);
1098 /// SimplifyLShrInst - Given operands for an LShr, see if we can
1099 /// fold the result. If not, this returns null.
1100 static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1101 const TargetData *TD, const DominatorTree *DT,
1102 unsigned MaxRecurse) {
1103 if (Value *V = SimplifyShift(Instruction::LShr, Op0, Op1, TD, DT, MaxRecurse))
1107 if (match(Op0, m_Undef()))
1108 return Constant::getNullValue(Op0->getType());
1110 // (X << A) >> A -> X
1112 if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) &&
1113 cast<OverflowingBinaryOperator>(Op0)->hasNoUnsignedWrap())
1119 Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1120 const TargetData *TD, const DominatorTree *DT) {
1121 return ::SimplifyLShrInst(Op0, Op1, isExact, TD, DT, RecursionLimit);
1124 /// SimplifyAShrInst - Given operands for an AShr, see if we can
1125 /// fold the result. If not, this returns null.
1126 static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1127 const TargetData *TD, const DominatorTree *DT,
1128 unsigned MaxRecurse) {
1129 if (Value *V = SimplifyShift(Instruction::AShr, Op0, Op1, TD, DT, MaxRecurse))
1132 // all ones >>a X -> all ones
1133 if (match(Op0, m_AllOnes()))
1136 // undef >>a X -> all ones
1137 if (match(Op0, m_Undef()))
1138 return Constant::getAllOnesValue(Op0->getType());
1140 // (X << A) >> A -> X
1142 if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) &&
1143 cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap())
1149 Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1150 const TargetData *TD, const DominatorTree *DT) {
1151 return ::SimplifyAShrInst(Op0, Op1, isExact, TD, DT, RecursionLimit);
1154 /// SimplifyAndInst - Given operands for an And, see if we can
1155 /// fold the result. If not, this returns null.
1156 static Value *SimplifyAndInst(Value *Op0, Value *Op1, const TargetData *TD,
1157 const DominatorTree *DT, unsigned MaxRecurse) {
1158 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1159 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1160 Constant *Ops[] = { CLHS, CRHS };
1161 return ConstantFoldInstOperands(Instruction::And, CLHS->getType(),
1165 // Canonicalize the constant to the RHS.
1166 std::swap(Op0, Op1);
1170 if (match(Op1, m_Undef()))
1171 return Constant::getNullValue(Op0->getType());
1178 if (match(Op1, m_Zero()))
1182 if (match(Op1, m_AllOnes()))
1185 // A & ~A = ~A & A = 0
1186 if (match(Op0, m_Not(m_Specific(Op1))) ||
1187 match(Op1, m_Not(m_Specific(Op0))))
1188 return Constant::getNullValue(Op0->getType());
1191 Value *A = 0, *B = 0;
1192 if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
1193 (A == Op1 || B == Op1))
1197 if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
1198 (A == Op0 || B == Op0))
1201 // A & (-A) = A if A is a power of two or zero.
1202 if (match(Op0, m_Neg(m_Specific(Op1))) ||
1203 match(Op1, m_Neg(m_Specific(Op0)))) {
1204 if (isPowerOfTwo(Op0, TD, /*OrZero*/true))
1206 if (isPowerOfTwo(Op1, TD, /*OrZero*/true))
1210 // Try some generic simplifications for associative operations.
1211 if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, TD, DT,
1215 // And distributes over Or. Try some generic simplifications based on this.
1216 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1217 TD, DT, MaxRecurse))
1220 // And distributes over Xor. Try some generic simplifications based on this.
1221 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
1222 TD, DT, MaxRecurse))
1225 // Or distributes over And. Try some generic simplifications based on this.
1226 if (Value *V = FactorizeBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1227 TD, DT, MaxRecurse))
1230 // If the operation is with the result of a select instruction, check whether
1231 // operating on either branch of the select always yields the same value.
1232 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1233 if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, TD, DT,
1237 // If the operation is with the result of a phi instruction, check whether
1238 // operating on all incoming values of the phi always yields the same value.
1239 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1240 if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, TD, DT,
1247 Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const TargetData *TD,
1248 const DominatorTree *DT) {
1249 return ::SimplifyAndInst(Op0, Op1, TD, DT, RecursionLimit);
1252 /// SimplifyOrInst - Given operands for an Or, see if we can
1253 /// fold the result. If not, this returns null.
1254 static Value *SimplifyOrInst(Value *Op0, Value *Op1, const TargetData *TD,
1255 const DominatorTree *DT, unsigned MaxRecurse) {
1256 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1257 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1258 Constant *Ops[] = { CLHS, CRHS };
1259 return ConstantFoldInstOperands(Instruction::Or, CLHS->getType(),
1263 // Canonicalize the constant to the RHS.
1264 std::swap(Op0, Op1);
1268 if (match(Op1, m_Undef()))
1269 return Constant::getAllOnesValue(Op0->getType());
1276 if (match(Op1, m_Zero()))
1280 if (match(Op1, m_AllOnes()))
1283 // A | ~A = ~A | A = -1
1284 if (match(Op0, m_Not(m_Specific(Op1))) ||
1285 match(Op1, m_Not(m_Specific(Op0))))
1286 return Constant::getAllOnesValue(Op0->getType());
1289 Value *A = 0, *B = 0;
1290 if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
1291 (A == Op1 || B == Op1))
1295 if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
1296 (A == Op0 || B == Op0))
1299 // ~(A & ?) | A = -1
1300 if (match(Op0, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1301 (A == Op1 || B == Op1))
1302 return Constant::getAllOnesValue(Op1->getType());
1304 // A | ~(A & ?) = -1
1305 if (match(Op1, m_Not(m_And(m_Value(A), m_Value(B)))) &&
1306 (A == Op0 || B == Op0))
1307 return Constant::getAllOnesValue(Op0->getType());
1309 // Try some generic simplifications for associative operations.
1310 if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, TD, DT,
1314 // Or distributes over And. Try some generic simplifications based on this.
1315 if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And,
1316 TD, DT, MaxRecurse))
1319 // And distributes over Or. Try some generic simplifications based on this.
1320 if (Value *V = FactorizeBinOp(Instruction::Or, Op0, Op1, Instruction::And,
1321 TD, DT, MaxRecurse))
1324 // If the operation is with the result of a select instruction, check whether
1325 // operating on either branch of the select always yields the same value.
1326 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1327 if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, TD, DT,
1331 // If the operation is with the result of a phi instruction, check whether
1332 // operating on all incoming values of the phi always yields the same value.
1333 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1334 if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, TD, DT,
1341 Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const TargetData *TD,
1342 const DominatorTree *DT) {
1343 return ::SimplifyOrInst(Op0, Op1, TD, DT, RecursionLimit);
1346 /// SimplifyXorInst - Given operands for a Xor, see if we can
1347 /// fold the result. If not, this returns null.
1348 static Value *SimplifyXorInst(Value *Op0, Value *Op1, const TargetData *TD,
1349 const DominatorTree *DT, unsigned MaxRecurse) {
1350 if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
1351 if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
1352 Constant *Ops[] = { CLHS, CRHS };
1353 return ConstantFoldInstOperands(Instruction::Xor, CLHS->getType(),
1357 // Canonicalize the constant to the RHS.
1358 std::swap(Op0, Op1);
1361 // A ^ undef -> undef
1362 if (match(Op1, m_Undef()))
1366 if (match(Op1, m_Zero()))
1371 return Constant::getNullValue(Op0->getType());
1373 // A ^ ~A = ~A ^ A = -1
1374 if (match(Op0, m_Not(m_Specific(Op1))) ||
1375 match(Op1, m_Not(m_Specific(Op0))))
1376 return Constant::getAllOnesValue(Op0->getType());
1378 // Try some generic simplifications for associative operations.
1379 if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, TD, DT,
1383 // And distributes over Xor. Try some generic simplifications based on this.
1384 if (Value *V = FactorizeBinOp(Instruction::Xor, Op0, Op1, Instruction::And,
1385 TD, DT, MaxRecurse))
1388 // Threading Xor over selects and phi nodes is pointless, so don't bother.
1389 // Threading over the select in "A ^ select(cond, B, C)" means evaluating
1390 // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
1391 // only if B and C are equal. If B and C are equal then (since we assume
1392 // that operands have already been simplified) "select(cond, B, C)" should
1393 // have been simplified to the common value of B and C already. Analysing
1394 // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
1395 // for threading over phi nodes.
1400 Value *llvm::SimplifyXorInst(Value *Op0, Value *Op1, const TargetData *TD,
1401 const DominatorTree *DT) {
1402 return ::SimplifyXorInst(Op0, Op1, TD, DT, RecursionLimit);
1405 static Type *GetCompareTy(Value *Op) {
1406 return CmpInst::makeCmpResultType(Op->getType());
1409 /// ExtractEquivalentCondition - Rummage around inside V looking for something
1410 /// equivalent to the comparison "LHS Pred RHS". Return such a value if found,
1411 /// otherwise return null. Helper function for analyzing max/min idioms.
1412 static Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred,
1413 Value *LHS, Value *RHS) {
1414 SelectInst *SI = dyn_cast<SelectInst>(V);
1417 CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
1420 Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
1421 if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
1423 if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
1424 LHS == CmpRHS && RHS == CmpLHS)
1429 /// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
1430 /// fold the result. If not, this returns null.
1431 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
1432 const TargetData *TD, const DominatorTree *DT,
1433 unsigned MaxRecurse) {
1434 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
1435 assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
1437 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
1438 if (Constant *CRHS = dyn_cast<Constant>(RHS))
1439 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, TD);
1441 // If we have a constant, make sure it is on the RHS.
1442 std::swap(LHS, RHS);
1443 Pred = CmpInst::getSwappedPredicate(Pred);
1446 Type *ITy = GetCompareTy(LHS); // The return type.
1447 Type *OpTy = LHS->getType(); // The operand type.
1449 // icmp X, X -> true/false
1450 // X icmp undef -> true/false. For example, icmp ugt %X, undef -> false
1451 // because X could be 0.
1452 if (LHS == RHS || isa<UndefValue>(RHS))
1453 return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
1455 // Special case logic when the operands have i1 type.
1456 if (OpTy->isIntegerTy(1) || (OpTy->isVectorTy() &&
1457 cast<VectorType>(OpTy)->getElementType()->isIntegerTy(1))) {
1460 case ICmpInst::ICMP_EQ:
1462 if (match(RHS, m_One()))
1465 case ICmpInst::ICMP_NE:
1467 if (match(RHS, m_Zero()))
1470 case ICmpInst::ICMP_UGT:
1472 if (match(RHS, m_Zero()))
1475 case ICmpInst::ICMP_UGE:
1477 if (match(RHS, m_One()))
1480 case ICmpInst::ICMP_SLT:
1482 if (match(RHS, m_Zero()))
1485 case ICmpInst::ICMP_SLE:
1487 if (match(RHS, m_One()))
1493 // icmp <alloca*>, <global/alloca*/null> - Different stack variables have
1494 // different addresses, and what's more the address of a stack variable is
1495 // never null or equal to the address of a global. Note that generalizing
1496 // to the case where LHS is a global variable address or null is pointless,
1497 // since if both LHS and RHS are constants then we already constant folded
1498 // the compare, and if only one of them is then we moved it to RHS already.
1499 if (isa<AllocaInst>(LHS) && (isa<GlobalValue>(RHS) || isa<AllocaInst>(RHS) ||
1500 isa<ConstantPointerNull>(RHS)))
1501 // We already know that LHS != RHS.
1502 return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred));
1504 // If we are comparing with zero then try hard since this is a common case.
1505 if (match(RHS, m_Zero())) {
1506 bool LHSKnownNonNegative, LHSKnownNegative;
1509 assert(false && "Unknown ICmp predicate!");
1510 case ICmpInst::ICMP_ULT:
1511 return getFalse(ITy);
1512 case ICmpInst::ICMP_UGE:
1513 return getTrue(ITy);
1514 case ICmpInst::ICMP_EQ:
1515 case ICmpInst::ICMP_ULE:
1516 if (isKnownNonZero(LHS, TD))
1517 return getFalse(ITy);
1519 case ICmpInst::ICMP_NE:
1520 case ICmpInst::ICMP_UGT:
1521 if (isKnownNonZero(LHS, TD))
1522 return getTrue(ITy);
1524 case ICmpInst::ICMP_SLT:
1525 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, TD);
1526 if (LHSKnownNegative)
1527 return getTrue(ITy);
1528 if (LHSKnownNonNegative)
1529 return getFalse(ITy);
1531 case ICmpInst::ICMP_SLE:
1532 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, TD);
1533 if (LHSKnownNegative)
1534 return getTrue(ITy);
1535 if (LHSKnownNonNegative && isKnownNonZero(LHS, TD))
1536 return getFalse(ITy);
1538 case ICmpInst::ICMP_SGE:
1539 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, TD);
1540 if (LHSKnownNegative)
1541 return getFalse(ITy);
1542 if (LHSKnownNonNegative)
1543 return getTrue(ITy);
1545 case ICmpInst::ICMP_SGT:
1546 ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, TD);
1547 if (LHSKnownNegative)
1548 return getFalse(ITy);
1549 if (LHSKnownNonNegative && isKnownNonZero(LHS, TD))
1550 return getTrue(ITy);
1555 // See if we are doing a comparison with a constant integer.
1556 if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
1557 // Rule out tautological comparisons (eg., ult 0 or uge 0).
1558 ConstantRange RHS_CR = ICmpInst::makeConstantRange(Pred, CI->getValue());
1559 if (RHS_CR.isEmptySet())
1560 return ConstantInt::getFalse(CI->getContext());
1561 if (RHS_CR.isFullSet())
1562 return ConstantInt::getTrue(CI->getContext());
1564 // Many binary operators with constant RHS have easy to compute constant
1565 // range. Use them to check whether the comparison is a tautology.
1566 uint32_t Width = CI->getBitWidth();
1567 APInt Lower = APInt(Width, 0);
1568 APInt Upper = APInt(Width, 0);
1570 if (match(LHS, m_URem(m_Value(), m_ConstantInt(CI2)))) {
1571 // 'urem x, CI2' produces [0, CI2).
1572 Upper = CI2->getValue();
1573 } else if (match(LHS, m_SRem(m_Value(), m_ConstantInt(CI2)))) {
1574 // 'srem x, CI2' produces (-|CI2|, |CI2|).
1575 Upper = CI2->getValue().abs();
1576 Lower = (-Upper) + 1;
1577 } else if (match(LHS, m_UDiv(m_ConstantInt(CI2), m_Value()))) {
1578 // 'udiv CI2, x' produces [0, CI2].
1579 Upper = CI2->getValue();
1580 } else if (match(LHS, m_UDiv(m_Value(), m_ConstantInt(CI2)))) {
1581 // 'udiv x, CI2' produces [0, UINT_MAX / CI2].
1582 APInt NegOne = APInt::getAllOnesValue(Width);
1584 Upper = NegOne.udiv(CI2->getValue()) + 1;
1585 } else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) {
1586 // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2].
1587 APInt IntMin = APInt::getSignedMinValue(Width);
1588 APInt IntMax = APInt::getSignedMaxValue(Width);
1589 APInt Val = CI2->getValue().abs();
1590 if (!Val.isMinValue()) {
1591 Lower = IntMin.sdiv(Val);
1592 Upper = IntMax.sdiv(Val) + 1;
1594 } else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) {
1595 // 'lshr x, CI2' produces [0, UINT_MAX >> CI2].
1596 APInt NegOne = APInt::getAllOnesValue(Width);
1597 if (CI2->getValue().ult(Width))
1598 Upper = NegOne.lshr(CI2->getValue()) + 1;
1599 } else if (match(LHS, m_AShr(m_Value(), m_ConstantInt(CI2)))) {
1600 // 'ashr x, CI2' produces [INT_MIN >> CI2, INT_MAX >> CI2].
1601 APInt IntMin = APInt::getSignedMinValue(Width);
1602 APInt IntMax = APInt::getSignedMaxValue(Width);
1603 if (CI2->getValue().ult(Width)) {
1604 Lower = IntMin.ashr(CI2->getValue());
1605 Upper = IntMax.ashr(CI2->getValue()) + 1;
1607 } else if (match(LHS, m_Or(m_Value(), m_ConstantInt(CI2)))) {
1608 // 'or x, CI2' produces [CI2, UINT_MAX].
1609 Lower = CI2->getValue();
1610 } else if (match(LHS, m_And(m_Value(), m_ConstantInt(CI2)))) {
1611 // 'and x, CI2' produces [0, CI2].
1612 Upper = CI2->getValue() + 1;
1614 if (Lower != Upper) {
1615 ConstantRange LHS_CR = ConstantRange(Lower, Upper);
1616 if (RHS_CR.contains(LHS_CR))
1617 return ConstantInt::getTrue(RHS->getContext());
1618 if (RHS_CR.inverse().contains(LHS_CR))
1619 return ConstantInt::getFalse(RHS->getContext());
1623 // Compare of cast, for example (zext X) != 0 -> X != 0
1624 if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
1625 Instruction *LI = cast<CastInst>(LHS);
1626 Value *SrcOp = LI->getOperand(0);
1627 Type *SrcTy = SrcOp->getType();
1628 Type *DstTy = LI->getType();
1630 // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
1631 // if the integer type is the same size as the pointer type.
1632 if (MaxRecurse && TD && isa<PtrToIntInst>(LI) &&
1633 TD->getPointerSizeInBits() == DstTy->getPrimitiveSizeInBits()) {
1634 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
1635 // Transfer the cast to the constant.
1636 if (Value *V = SimplifyICmpInst(Pred, SrcOp,
1637 ConstantExpr::getIntToPtr(RHSC, SrcTy),
1638 TD, DT, MaxRecurse-1))
1640 } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
1641 if (RI->getOperand(0)->getType() == SrcTy)
1642 // Compare without the cast.
1643 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
1644 TD, DT, MaxRecurse-1))
1649 if (isa<ZExtInst>(LHS)) {
1650 // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
1652 if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
1653 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
1654 // Compare X and Y. Note that signed predicates become unsigned.
1655 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
1656 SrcOp, RI->getOperand(0), TD, DT,
1660 // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
1661 // too. If not, then try to deduce the result of the comparison.
1662 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
1663 // Compute the constant that would happen if we truncated to SrcTy then
1664 // reextended to DstTy.
1665 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
1666 Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
1668 // If the re-extended constant didn't change then this is effectively
1669 // also a case of comparing two zero-extended values.
1670 if (RExt == CI && MaxRecurse)
1671 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
1672 SrcOp, Trunc, TD, DT, MaxRecurse-1))
1675 // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
1676 // there. Use this to work out the result of the comparison.
1680 assert(false && "Unknown ICmp predicate!");
1682 case ICmpInst::ICMP_EQ:
1683 case ICmpInst::ICMP_UGT:
1684 case ICmpInst::ICMP_UGE:
1685 return ConstantInt::getFalse(CI->getContext());
1687 case ICmpInst::ICMP_NE:
1688 case ICmpInst::ICMP_ULT:
1689 case ICmpInst::ICMP_ULE:
1690 return ConstantInt::getTrue(CI->getContext());
1692 // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
1693 // is non-negative then LHS <s RHS.
1694 case ICmpInst::ICMP_SGT:
1695 case ICmpInst::ICMP_SGE:
1696 return CI->getValue().isNegative() ?
1697 ConstantInt::getTrue(CI->getContext()) :
1698 ConstantInt::getFalse(CI->getContext());
1700 case ICmpInst::ICMP_SLT:
1701 case ICmpInst::ICMP_SLE:
1702 return CI->getValue().isNegative() ?
1703 ConstantInt::getFalse(CI->getContext()) :
1704 ConstantInt::getTrue(CI->getContext());
1710 if (isa<SExtInst>(LHS)) {
1711 // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
1713 if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
1714 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
1715 // Compare X and Y. Note that the predicate does not change.
1716 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
1717 TD, DT, MaxRecurse-1))
1720 // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
1721 // too. If not, then try to deduce the result of the comparison.
1722 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
1723 // Compute the constant that would happen if we truncated to SrcTy then
1724 // reextended to DstTy.
1725 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
1726 Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
1728 // If the re-extended constant didn't change then this is effectively
1729 // also a case of comparing two sign-extended values.
1730 if (RExt == CI && MaxRecurse)
1731 if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, TD, DT,
1735 // Otherwise the upper bits of LHS are all equal, while RHS has varying
1736 // bits there. Use this to work out the result of the comparison.
1740 assert(false && "Unknown ICmp predicate!");
1741 case ICmpInst::ICMP_EQ:
1742 return ConstantInt::getFalse(CI->getContext());
1743 case ICmpInst::ICMP_NE:
1744 return ConstantInt::getTrue(CI->getContext());
1746 // If RHS is non-negative then LHS <s RHS. If RHS is negative then
1748 case ICmpInst::ICMP_SGT:
1749 case ICmpInst::ICMP_SGE:
1750 return CI->getValue().isNegative() ?
1751 ConstantInt::getTrue(CI->getContext()) :
1752 ConstantInt::getFalse(CI->getContext());
1753 case ICmpInst::ICMP_SLT:
1754 case ICmpInst::ICMP_SLE:
1755 return CI->getValue().isNegative() ?
1756 ConstantInt::getFalse(CI->getContext()) :
1757 ConstantInt::getTrue(CI->getContext());
1759 // If LHS is non-negative then LHS <u RHS. If LHS is negative then
1761 case ICmpInst::ICMP_UGT:
1762 case ICmpInst::ICMP_UGE:
1763 // Comparison is true iff the LHS <s 0.
1765 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
1766 Constant::getNullValue(SrcTy),
1767 TD, DT, MaxRecurse-1))
1770 case ICmpInst::ICMP_ULT:
1771 case ICmpInst::ICMP_ULE:
1772 // Comparison is true iff the LHS >=s 0.
1774 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
1775 Constant::getNullValue(SrcTy),
1776 TD, DT, MaxRecurse-1))
1785 // Special logic for binary operators.
1786 BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
1787 BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
1788 if (MaxRecurse && (LBO || RBO)) {
1789 // Analyze the case when either LHS or RHS is an add instruction.
1790 Value *A = 0, *B = 0, *C = 0, *D = 0;
1791 // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
1792 bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
1793 if (LBO && LBO->getOpcode() == Instruction::Add) {
1794 A = LBO->getOperand(0); B = LBO->getOperand(1);
1795 NoLHSWrapProblem = ICmpInst::isEquality(Pred) ||
1796 (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
1797 (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
1799 if (RBO && RBO->getOpcode() == Instruction::Add) {
1800 C = RBO->getOperand(0); D = RBO->getOperand(1);
1801 NoRHSWrapProblem = ICmpInst::isEquality(Pred) ||
1802 (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
1803 (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
1806 // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
1807 if ((A == RHS || B == RHS) && NoLHSWrapProblem)
1808 if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
1809 Constant::getNullValue(RHS->getType()),
1810 TD, DT, MaxRecurse-1))
1813 // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
1814 if ((C == LHS || D == LHS) && NoRHSWrapProblem)
1815 if (Value *V = SimplifyICmpInst(Pred,
1816 Constant::getNullValue(LHS->getType()),
1817 C == LHS ? D : C, TD, DT, MaxRecurse-1))
1820 // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
1821 if (A && C && (A == C || A == D || B == C || B == D) &&
1822 NoLHSWrapProblem && NoRHSWrapProblem) {
1823 // Determine Y and Z in the form icmp (X+Y), (X+Z).
1824 Value *Y = (A == C || A == D) ? B : A;
1825 Value *Z = (C == A || C == B) ? D : C;
1826 if (Value *V = SimplifyICmpInst(Pred, Y, Z, TD, DT, MaxRecurse-1))
1831 if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
1832 bool KnownNonNegative, KnownNegative;
1836 case ICmpInst::ICMP_SGT:
1837 case ICmpInst::ICMP_SGE:
1838 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, TD);
1839 if (!KnownNonNegative)
1842 case ICmpInst::ICMP_EQ:
1843 case ICmpInst::ICMP_UGT:
1844 case ICmpInst::ICMP_UGE:
1845 return getFalse(ITy);
1846 case ICmpInst::ICMP_SLT:
1847 case ICmpInst::ICMP_SLE:
1848 ComputeSignBit(LHS, KnownNonNegative, KnownNegative, TD);
1849 if (!KnownNonNegative)
1852 case ICmpInst::ICMP_NE:
1853 case ICmpInst::ICMP_ULT:
1854 case ICmpInst::ICMP_ULE:
1855 return getTrue(ITy);
1858 if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
1859 bool KnownNonNegative, KnownNegative;
1863 case ICmpInst::ICMP_SGT:
1864 case ICmpInst::ICMP_SGE:
1865 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, TD);
1866 if (!KnownNonNegative)
1869 case ICmpInst::ICMP_NE:
1870 case ICmpInst::ICMP_UGT:
1871 case ICmpInst::ICMP_UGE:
1872 return getTrue(ITy);
1873 case ICmpInst::ICMP_SLT:
1874 case ICmpInst::ICMP_SLE:
1875 ComputeSignBit(RHS, KnownNonNegative, KnownNegative, TD);
1876 if (!KnownNonNegative)
1879 case ICmpInst::ICMP_EQ:
1880 case ICmpInst::ICMP_ULT:
1881 case ICmpInst::ICMP_ULE:
1882 return getFalse(ITy);
1887 if (LBO && match(LBO, m_UDiv(m_Specific(RHS), m_Value()))) {
1888 // icmp pred (X /u Y), X
1889 if (Pred == ICmpInst::ICMP_UGT)
1890 return getFalse(ITy);
1891 if (Pred == ICmpInst::ICMP_ULE)
1892 return getTrue(ITy);
1895 if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
1896 LBO->getOperand(1) == RBO->getOperand(1)) {
1897 switch (LBO->getOpcode()) {
1899 case Instruction::UDiv:
1900 case Instruction::LShr:
1901 if (ICmpInst::isSigned(Pred))
1904 case Instruction::SDiv:
1905 case Instruction::AShr:
1906 if (!LBO->isExact() || !RBO->isExact())
1908 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
1909 RBO->getOperand(0), TD, DT, MaxRecurse-1))
1912 case Instruction::Shl: {
1913 bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
1914 bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
1917 if (!NSW && ICmpInst::isSigned(Pred))
1919 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
1920 RBO->getOperand(0), TD, DT, MaxRecurse-1))
1927 // Simplify comparisons involving max/min.
1929 CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE;
1930 CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
1932 // Signed variants on "max(a,b)>=a -> true".
1933 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
1934 if (A != RHS) std::swap(A, B); // smax(A, B) pred A.
1935 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
1936 // We analyze this as smax(A, B) pred A.
1938 } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
1939 (A == LHS || B == LHS)) {
1940 if (A != LHS) std::swap(A, B); // A pred smax(A, B).
1941 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
1942 // We analyze this as smax(A, B) swapped-pred A.
1943 P = CmpInst::getSwappedPredicate(Pred);
1944 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
1945 (A == RHS || B == RHS)) {
1946 if (A != RHS) std::swap(A, B); // smin(A, B) pred A.
1947 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
1948 // We analyze this as smax(-A, -B) swapped-pred -A.
1949 // Note that we do not need to actually form -A or -B thanks to EqP.
1950 P = CmpInst::getSwappedPredicate(Pred);
1951 } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
1952 (A == LHS || B == LHS)) {
1953 if (A != LHS) std::swap(A, B); // A pred smin(A, B).
1954 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
1955 // We analyze this as smax(-A, -B) pred -A.
1956 // Note that we do not need to actually form -A or -B thanks to EqP.
1959 if (P != CmpInst::BAD_ICMP_PREDICATE) {
1960 // Cases correspond to "max(A, B) p A".
1964 case CmpInst::ICMP_EQ:
1965 case CmpInst::ICMP_SLE:
1966 // Equivalent to "A EqP B". This may be the same as the condition tested
1967 // in the max/min; if so, we can just return that.
1968 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
1970 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
1972 // Otherwise, see if "A EqP B" simplifies.
1974 if (Value *V = SimplifyICmpInst(EqP, A, B, TD, DT, MaxRecurse-1))
1977 case CmpInst::ICMP_NE:
1978 case CmpInst::ICMP_SGT: {
1979 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
1980 // Equivalent to "A InvEqP B". This may be the same as the condition
1981 // tested in the max/min; if so, we can just return that.
1982 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
1984 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
1986 // Otherwise, see if "A InvEqP B" simplifies.
1988 if (Value *V = SimplifyICmpInst(InvEqP, A, B, TD, DT, MaxRecurse-1))
1992 case CmpInst::ICMP_SGE:
1994 return getTrue(ITy);
1995 case CmpInst::ICMP_SLT:
1997 return getFalse(ITy);
2001 // Unsigned variants on "max(a,b)>=a -> true".
2002 P = CmpInst::BAD_ICMP_PREDICATE;
2003 if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
2004 if (A != RHS) std::swap(A, B); // umax(A, B) pred A.
2005 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2006 // We analyze this as umax(A, B) pred A.
2008 } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
2009 (A == LHS || B == LHS)) {
2010 if (A != LHS) std::swap(A, B); // A pred umax(A, B).
2011 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
2012 // We analyze this as umax(A, B) swapped-pred A.
2013 P = CmpInst::getSwappedPredicate(Pred);
2014 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2015 (A == RHS || B == RHS)) {
2016 if (A != RHS) std::swap(A, B); // umin(A, B) pred A.
2017 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2018 // We analyze this as umax(-A, -B) swapped-pred -A.
2019 // Note that we do not need to actually form -A or -B thanks to EqP.
2020 P = CmpInst::getSwappedPredicate(Pred);
2021 } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
2022 (A == LHS || B == LHS)) {
2023 if (A != LHS) std::swap(A, B); // A pred umin(A, B).
2024 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
2025 // We analyze this as umax(-A, -B) pred -A.
2026 // Note that we do not need to actually form -A or -B thanks to EqP.
2029 if (P != CmpInst::BAD_ICMP_PREDICATE) {
2030 // Cases correspond to "max(A, B) p A".
2034 case CmpInst::ICMP_EQ:
2035 case CmpInst::ICMP_ULE:
2036 // Equivalent to "A EqP B". This may be the same as the condition tested
2037 // in the max/min; if so, we can just return that.
2038 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
2040 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
2042 // Otherwise, see if "A EqP B" simplifies.
2044 if (Value *V = SimplifyICmpInst(EqP, A, B, TD, DT, MaxRecurse-1))
2047 case CmpInst::ICMP_NE:
2048 case CmpInst::ICMP_UGT: {
2049 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
2050 // Equivalent to "A InvEqP B". This may be the same as the condition
2051 // tested in the max/min; if so, we can just return that.
2052 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
2054 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
2056 // Otherwise, see if "A InvEqP B" simplifies.
2058 if (Value *V = SimplifyICmpInst(InvEqP, A, B, TD, DT, MaxRecurse-1))
2062 case CmpInst::ICMP_UGE:
2064 return getTrue(ITy);
2065 case CmpInst::ICMP_ULT:
2067 return getFalse(ITy);
2071 // Variants on "max(x,y) >= min(x,z)".
2073 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
2074 match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
2075 (A == C || A == D || B == C || B == D)) {
2076 // max(x, ?) pred min(x, ?).
2077 if (Pred == CmpInst::ICMP_SGE)
2079 return getTrue(ITy);
2080 if (Pred == CmpInst::ICMP_SLT)
2082 return getFalse(ITy);
2083 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
2084 match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
2085 (A == C || A == D || B == C || B == D)) {
2086 // min(x, ?) pred max(x, ?).
2087 if (Pred == CmpInst::ICMP_SLE)
2089 return getTrue(ITy);
2090 if (Pred == CmpInst::ICMP_SGT)
2092 return getFalse(ITy);
2093 } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
2094 match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
2095 (A == C || A == D || B == C || B == D)) {
2096 // max(x, ?) pred min(x, ?).
2097 if (Pred == CmpInst::ICMP_UGE)
2099 return getTrue(ITy);
2100 if (Pred == CmpInst::ICMP_ULT)
2102 return getFalse(ITy);
2103 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
2104 match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
2105 (A == C || A == D || B == C || B == D)) {
2106 // min(x, ?) pred max(x, ?).
2107 if (Pred == CmpInst::ICMP_ULE)
2109 return getTrue(ITy);
2110 if (Pred == CmpInst::ICMP_UGT)
2112 return getFalse(ITy);
2115 // If the comparison is with the result of a select instruction, check whether
2116 // comparing with either branch of the select always yields the same value.
2117 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2118 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, TD, DT, MaxRecurse))
2121 // If the comparison is with the result of a phi instruction, check whether
2122 // doing the compare with each incoming phi value yields a common result.
2123 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2124 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, TD, DT, MaxRecurse))
2130 Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2131 const TargetData *TD, const DominatorTree *DT) {
2132 return ::SimplifyICmpInst(Predicate, LHS, RHS, TD, DT, RecursionLimit);
2135 /// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can
2136 /// fold the result. If not, this returns null.
2137 static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2138 const TargetData *TD, const DominatorTree *DT,
2139 unsigned MaxRecurse) {
2140 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
2141 assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
2143 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
2144 if (Constant *CRHS = dyn_cast<Constant>(RHS))
2145 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, TD);
2147 // If we have a constant, make sure it is on the RHS.
2148 std::swap(LHS, RHS);
2149 Pred = CmpInst::getSwappedPredicate(Pred);
2152 // Fold trivial predicates.
2153 if (Pred == FCmpInst::FCMP_FALSE)
2154 return ConstantInt::get(GetCompareTy(LHS), 0);
2155 if (Pred == FCmpInst::FCMP_TRUE)
2156 return ConstantInt::get(GetCompareTy(LHS), 1);
2158 if (isa<UndefValue>(RHS)) // fcmp pred X, undef -> undef
2159 return UndefValue::get(GetCompareTy(LHS));
2161 // fcmp x,x -> true/false. Not all compares are foldable.
2163 if (CmpInst::isTrueWhenEqual(Pred))
2164 return ConstantInt::get(GetCompareTy(LHS), 1);
2165 if (CmpInst::isFalseWhenEqual(Pred))
2166 return ConstantInt::get(GetCompareTy(LHS), 0);
2169 // Handle fcmp with constant RHS
2170 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
2171 // If the constant is a nan, see if we can fold the comparison based on it.
2172 if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHSC)) {
2173 if (CFP->getValueAPF().isNaN()) {
2174 if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo"
2175 return ConstantInt::getFalse(CFP->getContext());
2176 assert(FCmpInst::isUnordered(Pred) &&
2177 "Comparison must be either ordered or unordered!");
2178 // True if unordered.
2179 return ConstantInt::getTrue(CFP->getContext());
2181 // Check whether the constant is an infinity.
2182 if (CFP->getValueAPF().isInfinity()) {
2183 if (CFP->getValueAPF().isNegative()) {
2185 case FCmpInst::FCMP_OLT:
2186 // No value is ordered and less than negative infinity.
2187 return ConstantInt::getFalse(CFP->getContext());
2188 case FCmpInst::FCMP_UGE:
2189 // All values are unordered with or at least negative infinity.
2190 return ConstantInt::getTrue(CFP->getContext());
2196 case FCmpInst::FCMP_OGT:
2197 // No value is ordered and greater than infinity.
2198 return ConstantInt::getFalse(CFP->getContext());
2199 case FCmpInst::FCMP_ULE:
2200 // All values are unordered with and at most infinity.
2201 return ConstantInt::getTrue(CFP->getContext());
2210 // If the comparison is with the result of a select instruction, check whether
2211 // comparing with either branch of the select always yields the same value.
2212 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2213 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, TD, DT, MaxRecurse))
2216 // If the comparison is with the result of a phi instruction, check whether
2217 // doing the compare with each incoming phi value yields a common result.
2218 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2219 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, TD, DT, MaxRecurse))
2225 Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2226 const TargetData *TD, const DominatorTree *DT) {
2227 return ::SimplifyFCmpInst(Predicate, LHS, RHS, TD, DT, RecursionLimit);
2230 /// SimplifySelectInst - Given operands for a SelectInst, see if we can fold
2231 /// the result. If not, this returns null.
2232 Value *llvm::SimplifySelectInst(Value *CondVal, Value *TrueVal, Value *FalseVal,
2233 const TargetData *TD, const DominatorTree *) {
2234 // select true, X, Y -> X
2235 // select false, X, Y -> Y
2236 if (ConstantInt *CB = dyn_cast<ConstantInt>(CondVal))
2237 return CB->getZExtValue() ? TrueVal : FalseVal;
2239 // select C, X, X -> X
2240 if (TrueVal == FalseVal)
2243 if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y
2244 if (isa<Constant>(TrueVal))
2248 if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X
2250 if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
2256 /// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
2257 /// fold the result. If not, this returns null.
2258 Value *llvm::SimplifyGEPInst(ArrayRef<Value *> Ops,
2259 const TargetData *TD, const DominatorTree *) {
2260 // The type of the GEP pointer operand.
2261 PointerType *PtrTy = cast<PointerType>(Ops[0]->getType());
2263 // getelementptr P -> P.
2264 if (Ops.size() == 1)
2267 if (isa<UndefValue>(Ops[0])) {
2268 // Compute the (pointer) type returned by the GEP instruction.
2269 Type *LastType = GetElementPtrInst::getIndexedType(PtrTy, Ops.slice(1));
2270 Type *GEPTy = PointerType::get(LastType, PtrTy->getAddressSpace());
2271 return UndefValue::get(GEPTy);
2274 if (Ops.size() == 2) {
2275 // getelementptr P, 0 -> P.
2276 if (ConstantInt *C = dyn_cast<ConstantInt>(Ops[1]))
2279 // getelementptr P, N -> P if P points to a type of zero size.
2281 Type *Ty = PtrTy->getElementType();
2282 if (Ty->isSized() && TD->getTypeAllocSize(Ty) == 0)
2287 // Check to see if this is constant foldable.
2288 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
2289 if (!isa<Constant>(Ops[i]))
2292 return ConstantExpr::getGetElementPtr(cast<Constant>(Ops[0]), Ops.slice(1));
2295 /// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we
2296 /// can fold the result. If not, this returns null.
2297 Value *llvm::SimplifyInsertValueInst(Value *Agg, Value *Val,
2298 ArrayRef<unsigned> Idxs,
2300 const DominatorTree *) {
2301 if (Constant *CAgg = dyn_cast<Constant>(Agg))
2302 if (Constant *CVal = dyn_cast<Constant>(Val))
2303 return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
2305 // insertvalue x, undef, n -> x
2306 if (match(Val, m_Undef()))
2309 // insertvalue x, (extractvalue y, n), n
2310 if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
2311 if (EV->getAggregateOperand()->getType() == Agg->getType() &&
2312 EV->getIndices() == Idxs) {
2313 // insertvalue undef, (extractvalue y, n), n -> y
2314 if (match(Agg, m_Undef()))
2315 return EV->getAggregateOperand();
2317 // insertvalue y, (extractvalue y, n), n -> y
2318 if (Agg == EV->getAggregateOperand())
2325 /// SimplifyPHINode - See if we can fold the given phi. If not, returns null.
2326 static Value *SimplifyPHINode(PHINode *PN, const DominatorTree *DT) {
2327 // If all of the PHI's incoming values are the same then replace the PHI node
2328 // with the common value.
2329 Value *CommonValue = 0;
2330 bool HasUndefInput = false;
2331 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
2332 Value *Incoming = PN->getIncomingValue(i);
2333 // If the incoming value is the phi node itself, it can safely be skipped.
2334 if (Incoming == PN) continue;
2335 if (isa<UndefValue>(Incoming)) {
2336 // Remember that we saw an undef value, but otherwise ignore them.
2337 HasUndefInput = true;
2340 if (CommonValue && Incoming != CommonValue)
2341 return 0; // Not the same, bail out.
2342 CommonValue = Incoming;
2345 // If CommonValue is null then all of the incoming values were either undef or
2346 // equal to the phi node itself.
2348 return UndefValue::get(PN->getType());
2350 // If we have a PHI node like phi(X, undef, X), where X is defined by some
2351 // instruction, we cannot return X as the result of the PHI node unless it
2352 // dominates the PHI block.
2354 return ValueDominatesPHI(CommonValue, PN, DT) ? CommonValue : 0;
2360 //=== Helper functions for higher up the class hierarchy.
2362 /// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
2363 /// fold the result. If not, this returns null.
2364 static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
2365 const TargetData *TD, const DominatorTree *DT,
2366 unsigned MaxRecurse) {
2368 case Instruction::Add:
2369 return SimplifyAddInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2370 TD, DT, MaxRecurse);
2371 case Instruction::Sub:
2372 return SimplifySubInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2373 TD, DT, MaxRecurse);
2374 case Instruction::Mul: return SimplifyMulInst (LHS, RHS, TD, DT, MaxRecurse);
2375 case Instruction::SDiv: return SimplifySDivInst(LHS, RHS, TD, DT, MaxRecurse);
2376 case Instruction::UDiv: return SimplifyUDivInst(LHS, RHS, TD, DT, MaxRecurse);
2377 case Instruction::FDiv: return SimplifyFDivInst(LHS, RHS, TD, DT, MaxRecurse);
2378 case Instruction::SRem: return SimplifySRemInst(LHS, RHS, TD, DT, MaxRecurse);
2379 case Instruction::URem: return SimplifyURemInst(LHS, RHS, TD, DT, MaxRecurse);
2380 case Instruction::FRem: return SimplifyFRemInst(LHS, RHS, TD, DT, MaxRecurse);
2381 case Instruction::Shl:
2382 return SimplifyShlInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
2383 TD, DT, MaxRecurse);
2384 case Instruction::LShr:
2385 return SimplifyLShrInst(LHS, RHS, /*isExact*/false, TD, DT, MaxRecurse);
2386 case Instruction::AShr:
2387 return SimplifyAShrInst(LHS, RHS, /*isExact*/false, TD, DT, MaxRecurse);
2388 case Instruction::And: return SimplifyAndInst(LHS, RHS, TD, DT, MaxRecurse);
2389 case Instruction::Or: return SimplifyOrInst (LHS, RHS, TD, DT, MaxRecurse);
2390 case Instruction::Xor: return SimplifyXorInst(LHS, RHS, TD, DT, MaxRecurse);
2392 if (Constant *CLHS = dyn_cast<Constant>(LHS))
2393 if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
2394 Constant *COps[] = {CLHS, CRHS};
2395 return ConstantFoldInstOperands(Opcode, LHS->getType(), COps, TD);
2398 // If the operation is associative, try some generic simplifications.
2399 if (Instruction::isAssociative(Opcode))
2400 if (Value *V = SimplifyAssociativeBinOp(Opcode, LHS, RHS, TD, DT,
2404 // If the operation is with the result of a select instruction, check whether
2405 // operating on either branch of the select always yields the same value.
2406 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
2407 if (Value *V = ThreadBinOpOverSelect(Opcode, LHS, RHS, TD, DT,
2411 // If the operation is with the result of a phi instruction, check whether
2412 // operating on all incoming values of the phi always yields the same value.
2413 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
2414 if (Value *V = ThreadBinOpOverPHI(Opcode, LHS, RHS, TD, DT, MaxRecurse))
2421 Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
2422 const TargetData *TD, const DominatorTree *DT) {
2423 return ::SimplifyBinOp(Opcode, LHS, RHS, TD, DT, RecursionLimit);
2426 /// SimplifyCmpInst - Given operands for a CmpInst, see if we can
2427 /// fold the result.
2428 static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2429 const TargetData *TD, const DominatorTree *DT,
2430 unsigned MaxRecurse) {
2431 if (CmpInst::isIntPredicate((CmpInst::Predicate)Predicate))
2432 return SimplifyICmpInst(Predicate, LHS, RHS, TD, DT, MaxRecurse);
2433 return SimplifyFCmpInst(Predicate, LHS, RHS, TD, DT, MaxRecurse);
2436 Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
2437 const TargetData *TD, const DominatorTree *DT) {
2438 return ::SimplifyCmpInst(Predicate, LHS, RHS, TD, DT, RecursionLimit);
2441 /// SimplifyInstruction - See if we can compute a simplified version of this
2442 /// instruction. If not, this returns null.
2443 Value *llvm::SimplifyInstruction(Instruction *I, const TargetData *TD,
2444 const DominatorTree *DT) {
2447 switch (I->getOpcode()) {
2449 Result = ConstantFoldInstruction(I, TD);
2451 case Instruction::Add:
2452 Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
2453 cast<BinaryOperator>(I)->hasNoSignedWrap(),
2454 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
2457 case Instruction::Sub:
2458 Result = SimplifySubInst(I->getOperand(0), I->getOperand(1),
2459 cast<BinaryOperator>(I)->hasNoSignedWrap(),
2460 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
2463 case Instruction::Mul:
2464 Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1), TD, DT);
2466 case Instruction::SDiv:
2467 Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), TD, DT);
2469 case Instruction::UDiv:
2470 Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), TD, DT);
2472 case Instruction::FDiv:
2473 Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1), TD, DT);
2475 case Instruction::SRem:
2476 Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), TD, DT);
2478 case Instruction::URem:
2479 Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), TD, DT);
2481 case Instruction::FRem:
2482 Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1), TD, DT);
2484 case Instruction::Shl:
2485 Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1),
2486 cast<BinaryOperator>(I)->hasNoSignedWrap(),
2487 cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
2490 case Instruction::LShr:
2491 Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
2492 cast<BinaryOperator>(I)->isExact(),
2495 case Instruction::AShr:
2496 Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
2497 cast<BinaryOperator>(I)->isExact(),
2500 case Instruction::And:
2501 Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1), TD, DT);
2503 case Instruction::Or:
2504 Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), TD, DT);
2506 case Instruction::Xor:
2507 Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1), TD, DT);
2509 case Instruction::ICmp:
2510 Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
2511 I->getOperand(0), I->getOperand(1), TD, DT);
2513 case Instruction::FCmp:
2514 Result = SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(),
2515 I->getOperand(0), I->getOperand(1), TD, DT);
2517 case Instruction::Select:
2518 Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
2519 I->getOperand(2), TD, DT);
2521 case Instruction::GetElementPtr: {
2522 SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end());
2523 Result = SimplifyGEPInst(Ops, TD, DT);
2526 case Instruction::InsertValue: {
2527 InsertValueInst *IV = cast<InsertValueInst>(I);
2528 Result = SimplifyInsertValueInst(IV->getAggregateOperand(),
2529 IV->getInsertedValueOperand(),
2530 IV->getIndices(), TD, DT);
2533 case Instruction::PHI:
2534 Result = SimplifyPHINode(cast<PHINode>(I), DT);
2538 /// If called on unreachable code, the above logic may report that the
2539 /// instruction simplified to itself. Make life easier for users by
2540 /// detecting that case here, returning a safe value instead.
2541 return Result == I ? UndefValue::get(I->getType()) : Result;
2544 /// ReplaceAndSimplifyAllUses - Perform From->replaceAllUsesWith(To) and then
2545 /// delete the From instruction. In addition to a basic RAUW, this does a
2546 /// recursive simplification of the newly formed instructions. This catches
2547 /// things where one simplification exposes other opportunities. This only
2548 /// simplifies and deletes scalar operations, it does not change the CFG.
2550 void llvm::ReplaceAndSimplifyAllUses(Instruction *From, Value *To,
2551 const TargetData *TD,
2552 const DominatorTree *DT) {
2553 assert(From != To && "ReplaceAndSimplifyAllUses(X,X) is not valid!");
2555 // FromHandle/ToHandle - This keeps a WeakVH on the from/to values so that
2556 // we can know if it gets deleted out from under us or replaced in a
2557 // recursive simplification.
2558 WeakVH FromHandle(From);
2559 WeakVH ToHandle(To);
2561 while (!From->use_empty()) {
2562 // Update the instruction to use the new value.
2563 Use &TheUse = From->use_begin().getUse();
2564 Instruction *User = cast<Instruction>(TheUse.getUser());
2567 // Check to see if the instruction can be folded due to the operand
2568 // replacement. For example changing (or X, Y) into (or X, -1) can replace
2569 // the 'or' with -1.
2570 Value *SimplifiedVal;
2572 // Sanity check to make sure 'User' doesn't dangle across
2573 // SimplifyInstruction.
2574 AssertingVH<> UserHandle(User);
2576 SimplifiedVal = SimplifyInstruction(User, TD, DT);
2577 if (SimplifiedVal == 0) continue;
2580 // Recursively simplify this user to the new value.
2581 ReplaceAndSimplifyAllUses(User, SimplifiedVal, TD, DT);
2582 From = dyn_cast_or_null<Instruction>((Value*)FromHandle);
2585 assert(ToHandle && "To value deleted by recursive simplification?");
2587 // If the recursive simplification ended up revisiting and deleting
2588 // 'From' then we're done.
2593 // If 'From' has value handles referring to it, do a real RAUW to update them.
2594 From->replaceAllUsesWith(To);
2596 From->eraseFromParent();