1 //===- InstCombineAndOrXor.cpp --------------------------------------------===//
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 the visitAnd, visitOr, and visitXor functions.
12 //===----------------------------------------------------------------------===//
14 #include "InstCombineInternal.h"
15 #include "llvm/Analysis/InstructionSimplify.h"
16 #include "llvm/IR/ConstantRange.h"
17 #include "llvm/IR/Intrinsics.h"
18 #include "llvm/IR/PatternMatch.h"
19 #include "llvm/Transforms/Utils/CmpInstAnalysis.h"
21 using namespace PatternMatch;
23 #define DEBUG_TYPE "instcombine"
25 static inline Value *dyn_castNotVal(Value *V) {
26 // If this is not(not(x)) don't return that this is a not: we want the two
27 // not's to be folded first.
28 if (BinaryOperator::isNot(V)) {
29 Value *Operand = BinaryOperator::getNotArgument(V);
30 if (!IsFreeToInvert(Operand, Operand->hasOneUse()))
34 // Constants can be considered to be not'ed values...
35 if (ConstantInt *C = dyn_cast<ConstantInt>(V))
36 return ConstantInt::get(C->getType(), ~C->getValue());
40 /// Similar to getICmpCode but for FCmpInst. This encodes a fcmp predicate into
41 /// a three bit mask. It also returns whether it is an ordered predicate by
43 static unsigned getFCmpCode(FCmpInst::Predicate CC, bool &isOrdered) {
46 case FCmpInst::FCMP_ORD: isOrdered = true; return 0; // 000
47 case FCmpInst::FCMP_UNO: return 0; // 000
48 case FCmpInst::FCMP_OGT: isOrdered = true; return 1; // 001
49 case FCmpInst::FCMP_UGT: return 1; // 001
50 case FCmpInst::FCMP_OEQ: isOrdered = true; return 2; // 010
51 case FCmpInst::FCMP_UEQ: return 2; // 010
52 case FCmpInst::FCMP_OGE: isOrdered = true; return 3; // 011
53 case FCmpInst::FCMP_UGE: return 3; // 011
54 case FCmpInst::FCMP_OLT: isOrdered = true; return 4; // 100
55 case FCmpInst::FCMP_ULT: return 4; // 100
56 case FCmpInst::FCMP_ONE: isOrdered = true; return 5; // 101
57 case FCmpInst::FCMP_UNE: return 5; // 101
58 case FCmpInst::FCMP_OLE: isOrdered = true; return 6; // 110
59 case FCmpInst::FCMP_ULE: return 6; // 110
62 // Not expecting FCMP_FALSE and FCMP_TRUE;
63 llvm_unreachable("Unexpected FCmp predicate!");
67 /// This is the complement of getICmpCode, which turns an opcode and two
68 /// operands into either a constant true or false, or a brand new ICmp
69 /// instruction. The sign is passed in to determine which kind of predicate to
70 /// use in the new icmp instruction.
71 static Value *getNewICmpValue(bool Sign, unsigned Code, Value *LHS, Value *RHS,
72 InstCombiner::BuilderTy *Builder) {
73 ICmpInst::Predicate NewPred;
74 if (Value *NewConstant = getICmpValue(Sign, Code, LHS, RHS, NewPred))
76 return Builder->CreateICmp(NewPred, LHS, RHS);
79 /// This is the complement of getFCmpCode, which turns an opcode and two
80 /// operands into either a FCmp instruction. isordered is passed in to determine
81 /// which kind of predicate to use in the new fcmp instruction.
82 static Value *getFCmpValue(bool isordered, unsigned code,
83 Value *LHS, Value *RHS,
84 InstCombiner::BuilderTy *Builder) {
85 CmpInst::Predicate Pred;
87 default: llvm_unreachable("Illegal FCmp code!");
88 case 0: Pred = isordered ? FCmpInst::FCMP_ORD : FCmpInst::FCMP_UNO; break;
89 case 1: Pred = isordered ? FCmpInst::FCMP_OGT : FCmpInst::FCMP_UGT; break;
90 case 2: Pred = isordered ? FCmpInst::FCMP_OEQ : FCmpInst::FCMP_UEQ; break;
91 case 3: Pred = isordered ? FCmpInst::FCMP_OGE : FCmpInst::FCMP_UGE; break;
92 case 4: Pred = isordered ? FCmpInst::FCMP_OLT : FCmpInst::FCMP_ULT; break;
93 case 5: Pred = isordered ? FCmpInst::FCMP_ONE : FCmpInst::FCMP_UNE; break;
94 case 6: Pred = isordered ? FCmpInst::FCMP_OLE : FCmpInst::FCMP_ULE; break;
97 return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 1);
98 Pred = FCmpInst::FCMP_ORD; break;
100 return Builder->CreateFCmp(Pred, LHS, RHS);
103 /// \brief Transform BITWISE_OP(BSWAP(A),BSWAP(B)) to BSWAP(BITWISE_OP(A, B))
104 /// \param I Binary operator to transform.
105 /// \return Pointer to node that must replace the original binary operator, or
106 /// null pointer if no transformation was made.
107 Value *InstCombiner::SimplifyBSwap(BinaryOperator &I) {
108 IntegerType *ITy = dyn_cast<IntegerType>(I.getType());
111 if (I.getType()->isVectorTy()) return nullptr;
113 // Can only do bitwise ops.
114 unsigned Op = I.getOpcode();
115 if (Op != Instruction::And && Op != Instruction::Or &&
116 Op != Instruction::Xor)
119 Value *OldLHS = I.getOperand(0);
120 Value *OldRHS = I.getOperand(1);
121 ConstantInt *ConstLHS = dyn_cast<ConstantInt>(OldLHS);
122 ConstantInt *ConstRHS = dyn_cast<ConstantInt>(OldRHS);
123 IntrinsicInst *IntrLHS = dyn_cast<IntrinsicInst>(OldLHS);
124 IntrinsicInst *IntrRHS = dyn_cast<IntrinsicInst>(OldRHS);
125 bool IsBswapLHS = (IntrLHS && IntrLHS->getIntrinsicID() == Intrinsic::bswap);
126 bool IsBswapRHS = (IntrRHS && IntrRHS->getIntrinsicID() == Intrinsic::bswap);
128 if (!IsBswapLHS && !IsBswapRHS)
131 if (!IsBswapLHS && !ConstLHS)
134 if (!IsBswapRHS && !ConstRHS)
137 /// OP( BSWAP(x), BSWAP(y) ) -> BSWAP( OP(x, y) )
138 /// OP( BSWAP(x), CONSTANT ) -> BSWAP( OP(x, BSWAP(CONSTANT) ) )
139 Value *NewLHS = IsBswapLHS ? IntrLHS->getOperand(0) :
140 Builder->getInt(ConstLHS->getValue().byteSwap());
142 Value *NewRHS = IsBswapRHS ? IntrRHS->getOperand(0) :
143 Builder->getInt(ConstRHS->getValue().byteSwap());
145 Value *BinOp = nullptr;
146 if (Op == Instruction::And)
147 BinOp = Builder->CreateAnd(NewLHS, NewRHS);
148 else if (Op == Instruction::Or)
149 BinOp = Builder->CreateOr(NewLHS, NewRHS);
150 else //if (Op == Instruction::Xor)
151 BinOp = Builder->CreateXor(NewLHS, NewRHS);
153 Module *M = I.getParent()->getParent()->getParent();
154 Function *F = Intrinsic::getDeclaration(M, Intrinsic::bswap, ITy);
155 return Builder->CreateCall(F, BinOp);
158 /// This handles expressions of the form ((val OP C1) & C2). Where
159 /// the Op parameter is 'OP', OpRHS is 'C1', and AndRHS is 'C2'. Op is
160 /// guaranteed to be a binary operator.
161 Instruction *InstCombiner::OptAndOp(Instruction *Op,
164 BinaryOperator &TheAnd) {
165 Value *X = Op->getOperand(0);
166 Constant *Together = nullptr;
168 Together = ConstantExpr::getAnd(AndRHS, OpRHS);
170 switch (Op->getOpcode()) {
171 case Instruction::Xor:
172 if (Op->hasOneUse()) {
173 // (X ^ C1) & C2 --> (X & C2) ^ (C1&C2)
174 Value *And = Builder->CreateAnd(X, AndRHS);
176 return BinaryOperator::CreateXor(And, Together);
179 case Instruction::Or:
180 if (Op->hasOneUse()){
181 if (Together != OpRHS) {
182 // (X | C1) & C2 --> (X | (C1&C2)) & C2
183 Value *Or = Builder->CreateOr(X, Together);
185 return BinaryOperator::CreateAnd(Or, AndRHS);
188 ConstantInt *TogetherCI = dyn_cast<ConstantInt>(Together);
189 if (TogetherCI && !TogetherCI->isZero()){
190 // (X | C1) & C2 --> (X & (C2^(C1&C2))) | C1
191 // NOTE: This reduces the number of bits set in the & mask, which
192 // can expose opportunities for store narrowing.
193 Together = ConstantExpr::getXor(AndRHS, Together);
194 Value *And = Builder->CreateAnd(X, Together);
196 return BinaryOperator::CreateOr(And, OpRHS);
201 case Instruction::Add:
202 if (Op->hasOneUse()) {
203 // Adding a one to a single bit bit-field should be turned into an XOR
204 // of the bit. First thing to check is to see if this AND is with a
205 // single bit constant.
206 const APInt &AndRHSV = AndRHS->getValue();
208 // If there is only one bit set.
209 if (AndRHSV.isPowerOf2()) {
210 // Ok, at this point, we know that we are masking the result of the
211 // ADD down to exactly one bit. If the constant we are adding has
212 // no bits set below this bit, then we can eliminate the ADD.
213 const APInt& AddRHS = OpRHS->getValue();
215 // Check to see if any bits below the one bit set in AndRHSV are set.
216 if ((AddRHS & (AndRHSV-1)) == 0) {
217 // If not, the only thing that can effect the output of the AND is
218 // the bit specified by AndRHSV. If that bit is set, the effect of
219 // the XOR is to toggle the bit. If it is clear, then the ADD has
221 if ((AddRHS & AndRHSV) == 0) { // Bit is not set, noop
222 TheAnd.setOperand(0, X);
225 // Pull the XOR out of the AND.
226 Value *NewAnd = Builder->CreateAnd(X, AndRHS);
227 NewAnd->takeName(Op);
228 return BinaryOperator::CreateXor(NewAnd, AndRHS);
235 case Instruction::Shl: {
236 // We know that the AND will not produce any of the bits shifted in, so if
237 // the anded constant includes them, clear them now!
239 uint32_t BitWidth = AndRHS->getType()->getBitWidth();
240 uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth);
241 APInt ShlMask(APInt::getHighBitsSet(BitWidth, BitWidth-OpRHSVal));
242 ConstantInt *CI = Builder->getInt(AndRHS->getValue() & ShlMask);
244 if (CI->getValue() == ShlMask)
245 // Masking out bits that the shift already masks.
246 return ReplaceInstUsesWith(TheAnd, Op); // No need for the and.
248 if (CI != AndRHS) { // Reducing bits set in and.
249 TheAnd.setOperand(1, CI);
254 case Instruction::LShr: {
255 // We know that the AND will not produce any of the bits shifted in, so if
256 // the anded constant includes them, clear them now! This only applies to
257 // unsigned shifts, because a signed shr may bring in set bits!
259 uint32_t BitWidth = AndRHS->getType()->getBitWidth();
260 uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth);
261 APInt ShrMask(APInt::getLowBitsSet(BitWidth, BitWidth - OpRHSVal));
262 ConstantInt *CI = Builder->getInt(AndRHS->getValue() & ShrMask);
264 if (CI->getValue() == ShrMask)
265 // Masking out bits that the shift already masks.
266 return ReplaceInstUsesWith(TheAnd, Op);
269 TheAnd.setOperand(1, CI); // Reduce bits set in and cst.
274 case Instruction::AShr:
276 // See if this is shifting in some sign extension, then masking it out
278 if (Op->hasOneUse()) {
279 uint32_t BitWidth = AndRHS->getType()->getBitWidth();
280 uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth);
281 APInt ShrMask(APInt::getLowBitsSet(BitWidth, BitWidth - OpRHSVal));
282 Constant *C = Builder->getInt(AndRHS->getValue() & ShrMask);
283 if (C == AndRHS) { // Masking out bits shifted in.
284 // (Val ashr C1) & C2 -> (Val lshr C1) & C2
285 // Make the argument unsigned.
286 Value *ShVal = Op->getOperand(0);
287 ShVal = Builder->CreateLShr(ShVal, OpRHS, Op->getName());
288 return BinaryOperator::CreateAnd(ShVal, AndRHS, TheAnd.getName());
296 /// Emit a computation of: (V >= Lo && V < Hi) if Inside is true, otherwise
297 /// (V < Lo || V >= Hi). In practice, we emit the more efficient
298 /// (V-Lo) \<u Hi-Lo. This method expects that Lo <= Hi. isSigned indicates
299 /// whether to treat the V, Lo and HI as signed or not. IB is the location to
300 /// insert new instructions.
301 Value *InstCombiner::InsertRangeTest(Value *V, Constant *Lo, Constant *Hi,
302 bool isSigned, bool Inside) {
303 assert(cast<ConstantInt>(ConstantExpr::getICmp((isSigned ?
304 ICmpInst::ICMP_SLE:ICmpInst::ICMP_ULE), Lo, Hi))->getZExtValue() &&
305 "Lo is not <= Hi in range emission code!");
308 if (Lo == Hi) // Trivially false.
309 return Builder->getFalse();
311 // V >= Min && V < Hi --> V < Hi
312 if (cast<ConstantInt>(Lo)->isMinValue(isSigned)) {
313 ICmpInst::Predicate pred = (isSigned ?
314 ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT);
315 return Builder->CreateICmp(pred, V, Hi);
318 // Emit V-Lo <u Hi-Lo
319 Constant *NegLo = ConstantExpr::getNeg(Lo);
320 Value *Add = Builder->CreateAdd(V, NegLo, V->getName()+".off");
321 Constant *UpperBound = ConstantExpr::getAdd(NegLo, Hi);
322 return Builder->CreateICmpULT(Add, UpperBound);
325 if (Lo == Hi) // Trivially true.
326 return Builder->getTrue();
328 // V < Min || V >= Hi -> V > Hi-1
329 Hi = SubOne(cast<ConstantInt>(Hi));
330 if (cast<ConstantInt>(Lo)->isMinValue(isSigned)) {
331 ICmpInst::Predicate pred = (isSigned ?
332 ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT);
333 return Builder->CreateICmp(pred, V, Hi);
336 // Emit V-Lo >u Hi-1-Lo
337 // Note that Hi has already had one subtracted from it, above.
338 ConstantInt *NegLo = cast<ConstantInt>(ConstantExpr::getNeg(Lo));
339 Value *Add = Builder->CreateAdd(V, NegLo, V->getName()+".off");
340 Constant *LowerBound = ConstantExpr::getAdd(NegLo, Hi);
341 return Builder->CreateICmpUGT(Add, LowerBound);
344 /// Returns true iff Val consists of one contiguous run of 1s with any number
345 /// of 0s on either side. The 1s are allowed to wrap from LSB to MSB,
346 /// so 0x000FFF0, 0x0000FFFF, and 0xFF0000FF are all runs. 0x0F0F0000 is
347 /// not, since all 1s are not contiguous.
348 static bool isRunOfOnes(ConstantInt *Val, uint32_t &MB, uint32_t &ME) {
349 const APInt& V = Val->getValue();
350 uint32_t BitWidth = Val->getType()->getBitWidth();
351 if (!APIntOps::isShiftedMask(BitWidth, V)) return false;
353 // look for the first zero bit after the run of ones
354 MB = BitWidth - ((V - 1) ^ V).countLeadingZeros();
355 // look for the first non-zero bit
356 ME = V.getActiveBits();
360 /// This is part of an expression (LHS +/- RHS) & Mask, where isSub determines
361 /// whether the operator is a sub. If we can fold one of the following xforms:
363 /// ((A & N) +/- B) & Mask -> (A +/- B) & Mask iff N&Mask == Mask
364 /// ((A | N) +/- B) & Mask -> (A +/- B) & Mask iff N&Mask == 0
365 /// ((A ^ N) +/- B) & Mask -> (A +/- B) & Mask iff N&Mask == 0
367 /// return (A +/- B).
369 Value *InstCombiner::FoldLogicalPlusAnd(Value *LHS, Value *RHS,
370 ConstantInt *Mask, bool isSub,
372 Instruction *LHSI = dyn_cast<Instruction>(LHS);
373 if (!LHSI || LHSI->getNumOperands() != 2 ||
374 !isa<ConstantInt>(LHSI->getOperand(1))) return nullptr;
376 ConstantInt *N = cast<ConstantInt>(LHSI->getOperand(1));
378 switch (LHSI->getOpcode()) {
379 default: return nullptr;
380 case Instruction::And:
381 if (ConstantExpr::getAnd(N, Mask) == Mask) {
382 // If the AndRHS is a power of two minus one (0+1+), this is simple.
383 if ((Mask->getValue().countLeadingZeros() +
384 Mask->getValue().countPopulation()) ==
385 Mask->getValue().getBitWidth())
388 // Otherwise, if Mask is 0+1+0+, and if B is known to have the low 0+
389 // part, we don't need any explicit masks to take them out of A. If that
390 // is all N is, ignore it.
391 uint32_t MB = 0, ME = 0;
392 if (isRunOfOnes(Mask, MB, ME)) { // begin/end bit of run, inclusive
393 uint32_t BitWidth = cast<IntegerType>(RHS->getType())->getBitWidth();
394 APInt Mask(APInt::getLowBitsSet(BitWidth, MB-1));
395 if (MaskedValueIsZero(RHS, Mask, 0, &I))
400 case Instruction::Or:
401 case Instruction::Xor:
402 // If the AndRHS is a power of two minus one (0+1+), and N&Mask == 0
403 if ((Mask->getValue().countLeadingZeros() +
404 Mask->getValue().countPopulation()) == Mask->getValue().getBitWidth()
405 && ConstantExpr::getAnd(N, Mask)->isNullValue())
411 return Builder->CreateSub(LHSI->getOperand(0), RHS, "fold");
412 return Builder->CreateAdd(LHSI->getOperand(0), RHS, "fold");
415 /// enum for classifying (icmp eq (A & B), C) and (icmp ne (A & B), C)
416 /// One of A and B is considered the mask, the other the value. This is
417 /// described as the "AMask" or "BMask" part of the enum. If the enum
418 /// contains only "Mask", then both A and B can be considered masks.
419 /// If A is the mask, then it was proven, that (A & C) == C. This
420 /// is trivial if C == A, or C == 0. If both A and C are constants, this
421 /// proof is also easy.
422 /// For the following explanations we assume that A is the mask.
423 /// The part "AllOnes" declares, that the comparison is true only
424 /// if (A & B) == A, or all bits of A are set in B.
425 /// Example: (icmp eq (A & 3), 3) -> FoldMskICmp_AMask_AllOnes
426 /// The part "AllZeroes" declares, that the comparison is true only
427 /// if (A & B) == 0, or all bits of A are cleared in B.
428 /// Example: (icmp eq (A & 3), 0) -> FoldMskICmp_Mask_AllZeroes
429 /// The part "Mixed" declares, that (A & B) == C and C might or might not
430 /// contain any number of one bits and zero bits.
431 /// Example: (icmp eq (A & 3), 1) -> FoldMskICmp_AMask_Mixed
432 /// The Part "Not" means, that in above descriptions "==" should be replaced
434 /// Example: (icmp ne (A & 3), 3) -> FoldMskICmp_AMask_NotAllOnes
435 /// If the mask A contains a single bit, then the following is equivalent:
436 /// (icmp eq (A & B), A) equals (icmp ne (A & B), 0)
437 /// (icmp ne (A & B), A) equals (icmp eq (A & B), 0)
438 enum MaskedICmpType {
439 FoldMskICmp_AMask_AllOnes = 1,
440 FoldMskICmp_AMask_NotAllOnes = 2,
441 FoldMskICmp_BMask_AllOnes = 4,
442 FoldMskICmp_BMask_NotAllOnes = 8,
443 FoldMskICmp_Mask_AllZeroes = 16,
444 FoldMskICmp_Mask_NotAllZeroes = 32,
445 FoldMskICmp_AMask_Mixed = 64,
446 FoldMskICmp_AMask_NotMixed = 128,
447 FoldMskICmp_BMask_Mixed = 256,
448 FoldMskICmp_BMask_NotMixed = 512
451 /// Return the set of pattern classes (from MaskedICmpType)
452 /// that (icmp SCC (A & B), C) satisfies.
453 static unsigned getTypeOfMaskedICmp(Value* A, Value* B, Value* C,
454 ICmpInst::Predicate SCC)
456 ConstantInt *ACst = dyn_cast<ConstantInt>(A);
457 ConstantInt *BCst = dyn_cast<ConstantInt>(B);
458 ConstantInt *CCst = dyn_cast<ConstantInt>(C);
459 bool icmp_eq = (SCC == ICmpInst::ICMP_EQ);
460 bool icmp_abit = (ACst && !ACst->isZero() &&
461 ACst->getValue().isPowerOf2());
462 bool icmp_bbit = (BCst && !BCst->isZero() &&
463 BCst->getValue().isPowerOf2());
465 if (CCst && CCst->isZero()) {
466 // if C is zero, then both A and B qualify as mask
467 result |= (icmp_eq ? (FoldMskICmp_Mask_AllZeroes |
468 FoldMskICmp_Mask_AllZeroes |
469 FoldMskICmp_AMask_Mixed |
470 FoldMskICmp_BMask_Mixed)
471 : (FoldMskICmp_Mask_NotAllZeroes |
472 FoldMskICmp_Mask_NotAllZeroes |
473 FoldMskICmp_AMask_NotMixed |
474 FoldMskICmp_BMask_NotMixed));
476 result |= (icmp_eq ? (FoldMskICmp_AMask_NotAllOnes |
477 FoldMskICmp_AMask_NotMixed)
478 : (FoldMskICmp_AMask_AllOnes |
479 FoldMskICmp_AMask_Mixed));
481 result |= (icmp_eq ? (FoldMskICmp_BMask_NotAllOnes |
482 FoldMskICmp_BMask_NotMixed)
483 : (FoldMskICmp_BMask_AllOnes |
484 FoldMskICmp_BMask_Mixed));
488 result |= (icmp_eq ? (FoldMskICmp_AMask_AllOnes |
489 FoldMskICmp_AMask_Mixed)
490 : (FoldMskICmp_AMask_NotAllOnes |
491 FoldMskICmp_AMask_NotMixed));
493 result |= (icmp_eq ? (FoldMskICmp_Mask_NotAllZeroes |
494 FoldMskICmp_AMask_NotMixed)
495 : (FoldMskICmp_Mask_AllZeroes |
496 FoldMskICmp_AMask_Mixed));
497 } else if (ACst && CCst &&
498 ConstantExpr::getAnd(ACst, CCst) == CCst) {
499 result |= (icmp_eq ? FoldMskICmp_AMask_Mixed
500 : FoldMskICmp_AMask_NotMixed);
503 result |= (icmp_eq ? (FoldMskICmp_BMask_AllOnes |
504 FoldMskICmp_BMask_Mixed)
505 : (FoldMskICmp_BMask_NotAllOnes |
506 FoldMskICmp_BMask_NotMixed));
508 result |= (icmp_eq ? (FoldMskICmp_Mask_NotAllZeroes |
509 FoldMskICmp_BMask_NotMixed)
510 : (FoldMskICmp_Mask_AllZeroes |
511 FoldMskICmp_BMask_Mixed));
512 } else if (BCst && CCst &&
513 ConstantExpr::getAnd(BCst, CCst) == CCst) {
514 result |= (icmp_eq ? FoldMskICmp_BMask_Mixed
515 : FoldMskICmp_BMask_NotMixed);
520 /// Convert an analysis of a masked ICmp into its equivalent if all boolean
521 /// operations had the opposite sense. Since each "NotXXX" flag (recording !=)
522 /// is adjacent to the corresponding normal flag (recording ==), this just
523 /// involves swapping those bits over.
524 static unsigned conjugateICmpMask(unsigned Mask) {
526 NewMask = (Mask & (FoldMskICmp_AMask_AllOnes | FoldMskICmp_BMask_AllOnes |
527 FoldMskICmp_Mask_AllZeroes | FoldMskICmp_AMask_Mixed |
528 FoldMskICmp_BMask_Mixed))
532 (Mask & (FoldMskICmp_AMask_NotAllOnes | FoldMskICmp_BMask_NotAllOnes |
533 FoldMskICmp_Mask_NotAllZeroes | FoldMskICmp_AMask_NotMixed |
534 FoldMskICmp_BMask_NotMixed))
540 /// Decompose an icmp into the form ((X & Y) pred Z) if possible.
541 /// The returned predicate is either == or !=. Returns false if
542 /// decomposition fails.
543 static bool decomposeBitTestICmp(const ICmpInst *I, ICmpInst::Predicate &Pred,
544 Value *&X, Value *&Y, Value *&Z) {
545 ConstantInt *C = dyn_cast<ConstantInt>(I->getOperand(1));
549 switch (I->getPredicate()) {
552 case ICmpInst::ICMP_SLT:
553 // X < 0 is equivalent to (X & SignBit) != 0.
556 Y = ConstantInt::get(I->getContext(), APInt::getSignBit(C->getBitWidth()));
557 Pred = ICmpInst::ICMP_NE;
559 case ICmpInst::ICMP_SGT:
560 // X > -1 is equivalent to (X & SignBit) == 0.
561 if (!C->isAllOnesValue())
563 Y = ConstantInt::get(I->getContext(), APInt::getSignBit(C->getBitWidth()));
564 Pred = ICmpInst::ICMP_EQ;
566 case ICmpInst::ICMP_ULT:
567 // X <u 2^n is equivalent to (X & ~(2^n-1)) == 0.
568 if (!C->getValue().isPowerOf2())
570 Y = ConstantInt::get(I->getContext(), -C->getValue());
571 Pred = ICmpInst::ICMP_EQ;
573 case ICmpInst::ICMP_UGT:
574 // X >u 2^n-1 is equivalent to (X & ~(2^n-1)) != 0.
575 if (!(C->getValue() + 1).isPowerOf2())
577 Y = ConstantInt::get(I->getContext(), ~C->getValue());
578 Pred = ICmpInst::ICMP_NE;
582 X = I->getOperand(0);
583 Z = ConstantInt::getNullValue(C->getType());
587 /// Handle (icmp(A & B) ==/!= C) &/| (icmp(A & D) ==/!= E)
588 /// Return the set of pattern classes (from MaskedICmpType)
589 /// that both LHS and RHS satisfy.
590 static unsigned foldLogOpOfMaskedICmpsHelper(Value*& A,
591 Value*& B, Value*& C,
592 Value*& D, Value*& E,
593 ICmpInst *LHS, ICmpInst *RHS,
594 ICmpInst::Predicate &LHSCC,
595 ICmpInst::Predicate &RHSCC) {
596 if (LHS->getOperand(0)->getType() != RHS->getOperand(0)->getType()) return 0;
597 // vectors are not (yet?) supported
598 if (LHS->getOperand(0)->getType()->isVectorTy()) return 0;
600 // Here comes the tricky part:
601 // LHS might be of the form L11 & L12 == X, X == L21 & L22,
602 // and L11 & L12 == L21 & L22. The same goes for RHS.
603 // Now we must find those components L** and R**, that are equal, so
604 // that we can extract the parameters A, B, C, D, and E for the canonical
606 Value *L1 = LHS->getOperand(0);
607 Value *L2 = LHS->getOperand(1);
608 Value *L11,*L12,*L21,*L22;
609 // Check whether the icmp can be decomposed into a bit test.
610 if (decomposeBitTestICmp(LHS, LHSCC, L11, L12, L2)) {
611 L21 = L22 = L1 = nullptr;
613 // Look for ANDs in the LHS icmp.
614 if (!L1->getType()->isIntegerTy()) {
615 // You can icmp pointers, for example. They really aren't masks.
617 } else if (!match(L1, m_And(m_Value(L11), m_Value(L12)))) {
618 // Any icmp can be viewed as being trivially masked; if it allows us to
619 // remove one, it's worth it.
621 L12 = Constant::getAllOnesValue(L1->getType());
624 if (!L2->getType()->isIntegerTy()) {
625 // You can icmp pointers, for example. They really aren't masks.
627 } else if (!match(L2, m_And(m_Value(L21), m_Value(L22)))) {
629 L22 = Constant::getAllOnesValue(L2->getType());
633 // Bail if LHS was a icmp that can't be decomposed into an equality.
634 if (!ICmpInst::isEquality(LHSCC))
637 Value *R1 = RHS->getOperand(0);
638 Value *R2 = RHS->getOperand(1);
641 if (decomposeBitTestICmp(RHS, RHSCC, R11, R12, R2)) {
642 if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
644 } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
649 E = R2; R1 = nullptr; ok = true;
650 } else if (R1->getType()->isIntegerTy()) {
651 if (!match(R1, m_And(m_Value(R11), m_Value(R12)))) {
652 // As before, model no mask as a trivial mask if it'll let us do an
655 R12 = Constant::getAllOnesValue(R1->getType());
658 if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
659 A = R11; D = R12; E = R2; ok = true;
660 } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
661 A = R12; D = R11; E = R2; ok = true;
665 // Bail if RHS was a icmp that can't be decomposed into an equality.
666 if (!ICmpInst::isEquality(RHSCC))
669 // Look for ANDs in on the right side of the RHS icmp.
670 if (!ok && R2->getType()->isIntegerTy()) {
671 if (!match(R2, m_And(m_Value(R11), m_Value(R12)))) {
673 R12 = Constant::getAllOnesValue(R2->getType());
676 if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
677 A = R11; D = R12; E = R1; ok = true;
678 } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
679 A = R12; D = R11; E = R1; ok = true;
689 } else if (L12 == A) {
691 } else if (L21 == A) {
693 } else if (L22 == A) {
697 unsigned left_type = getTypeOfMaskedICmp(A, B, C, LHSCC);
698 unsigned right_type = getTypeOfMaskedICmp(A, D, E, RHSCC);
699 return left_type & right_type;
702 /// Try to fold (icmp(A & B) ==/!= C) &/| (icmp(A & D) ==/!= E)
703 /// into a single (icmp(A & X) ==/!= Y).
704 static Value *foldLogOpOfMaskedICmps(ICmpInst *LHS, ICmpInst *RHS, bool IsAnd,
705 llvm::InstCombiner::BuilderTy *Builder) {
706 Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr, *E = nullptr;
707 ICmpInst::Predicate LHSCC = LHS->getPredicate(), RHSCC = RHS->getPredicate();
708 unsigned mask = foldLogOpOfMaskedICmpsHelper(A, B, C, D, E, LHS, RHS,
710 if (mask == 0) return nullptr;
711 assert(ICmpInst::isEquality(LHSCC) && ICmpInst::isEquality(RHSCC) &&
712 "foldLogOpOfMaskedICmpsHelper must return an equality predicate.");
714 // In full generality:
715 // (icmp (A & B) Op C) | (icmp (A & D) Op E)
716 // == ![ (icmp (A & B) !Op C) & (icmp (A & D) !Op E) ]
718 // If the latter can be converted into (icmp (A & X) Op Y) then the former is
719 // equivalent to (icmp (A & X) !Op Y).
721 // Therefore, we can pretend for the rest of this function that we're dealing
722 // with the conjunction, provided we flip the sense of any comparisons (both
723 // input and output).
725 // In most cases we're going to produce an EQ for the "&&" case.
726 ICmpInst::Predicate NEWCC = IsAnd ? ICmpInst::ICMP_EQ : ICmpInst::ICMP_NE;
728 // Convert the masking analysis into its equivalent with negated
730 mask = conjugateICmpMask(mask);
733 if (mask & FoldMskICmp_Mask_AllZeroes) {
734 // (icmp eq (A & B), 0) & (icmp eq (A & D), 0)
735 // -> (icmp eq (A & (B|D)), 0)
736 Value *newOr = Builder->CreateOr(B, D);
737 Value *newAnd = Builder->CreateAnd(A, newOr);
738 // we can't use C as zero, because we might actually handle
739 // (icmp ne (A & B), B) & (icmp ne (A & D), D)
740 // with B and D, having a single bit set
741 Value *zero = Constant::getNullValue(A->getType());
742 return Builder->CreateICmp(NEWCC, newAnd, zero);
744 if (mask & FoldMskICmp_BMask_AllOnes) {
745 // (icmp eq (A & B), B) & (icmp eq (A & D), D)
746 // -> (icmp eq (A & (B|D)), (B|D))
747 Value *newOr = Builder->CreateOr(B, D);
748 Value *newAnd = Builder->CreateAnd(A, newOr);
749 return Builder->CreateICmp(NEWCC, newAnd, newOr);
751 if (mask & FoldMskICmp_AMask_AllOnes) {
752 // (icmp eq (A & B), A) & (icmp eq (A & D), A)
753 // -> (icmp eq (A & (B&D)), A)
754 Value *newAnd1 = Builder->CreateAnd(B, D);
755 Value *newAnd = Builder->CreateAnd(A, newAnd1);
756 return Builder->CreateICmp(NEWCC, newAnd, A);
759 // Remaining cases assume at least that B and D are constant, and depend on
760 // their actual values. This isn't strictly, necessary, just a "handle the
761 // easy cases for now" decision.
762 ConstantInt *BCst = dyn_cast<ConstantInt>(B);
763 if (!BCst) return nullptr;
764 ConstantInt *DCst = dyn_cast<ConstantInt>(D);
765 if (!DCst) return nullptr;
767 if (mask & (FoldMskICmp_Mask_NotAllZeroes | FoldMskICmp_BMask_NotAllOnes)) {
768 // (icmp ne (A & B), 0) & (icmp ne (A & D), 0) and
769 // (icmp ne (A & B), B) & (icmp ne (A & D), D)
770 // -> (icmp ne (A & B), 0) or (icmp ne (A & D), 0)
771 // Only valid if one of the masks is a superset of the other (check "B&D" is
772 // the same as either B or D).
773 APInt NewMask = BCst->getValue() & DCst->getValue();
775 if (NewMask == BCst->getValue())
777 else if (NewMask == DCst->getValue())
780 if (mask & FoldMskICmp_AMask_NotAllOnes) {
781 // (icmp ne (A & B), B) & (icmp ne (A & D), D)
782 // -> (icmp ne (A & B), A) or (icmp ne (A & D), A)
783 // Only valid if one of the masks is a superset of the other (check "B|D" is
784 // the same as either B or D).
785 APInt NewMask = BCst->getValue() | DCst->getValue();
787 if (NewMask == BCst->getValue())
789 else if (NewMask == DCst->getValue())
792 if (mask & FoldMskICmp_BMask_Mixed) {
793 // (icmp eq (A & B), C) & (icmp eq (A & D), E)
794 // We already know that B & C == C && D & E == E.
795 // If we can prove that (B & D) & (C ^ E) == 0, that is, the bits of
796 // C and E, which are shared by both the mask B and the mask D, don't
797 // contradict, then we can transform to
798 // -> (icmp eq (A & (B|D)), (C|E))
799 // Currently, we only handle the case of B, C, D, and E being constant.
800 // we can't simply use C and E, because we might actually handle
801 // (icmp ne (A & B), B) & (icmp eq (A & D), D)
802 // with B and D, having a single bit set
803 ConstantInt *CCst = dyn_cast<ConstantInt>(C);
804 if (!CCst) return nullptr;
805 ConstantInt *ECst = dyn_cast<ConstantInt>(E);
806 if (!ECst) return nullptr;
808 CCst = cast<ConstantInt>(ConstantExpr::getXor(BCst, CCst));
810 ECst = cast<ConstantInt>(ConstantExpr::getXor(DCst, ECst));
811 // if there is a conflict we should actually return a false for the
813 if (((BCst->getValue() & DCst->getValue()) &
814 (CCst->getValue() ^ ECst->getValue())) != 0)
815 return ConstantInt::get(LHS->getType(), !IsAnd);
816 Value *newOr1 = Builder->CreateOr(B, D);
817 Value *newOr2 = ConstantExpr::getOr(CCst, ECst);
818 Value *newAnd = Builder->CreateAnd(A, newOr1);
819 return Builder->CreateICmp(NEWCC, newAnd, newOr2);
824 /// Try to fold a signed range checked with lower bound 0 to an unsigned icmp.
825 /// Example: (icmp sge x, 0) & (icmp slt x, n) --> icmp ult x, n
826 /// If \p Inverted is true then the check is for the inverted range, e.g.
827 /// (icmp slt x, 0) | (icmp sgt x, n) --> icmp ugt x, n
828 Value *InstCombiner::simplifyRangeCheck(ICmpInst *Cmp0, ICmpInst *Cmp1,
830 // Check the lower range comparison, e.g. x >= 0
831 // InstCombine already ensured that if there is a constant it's on the RHS.
832 ConstantInt *RangeStart = dyn_cast<ConstantInt>(Cmp0->getOperand(1));
836 ICmpInst::Predicate Pred0 = (Inverted ? Cmp0->getInversePredicate() :
837 Cmp0->getPredicate());
839 // Accept x > -1 or x >= 0 (after potentially inverting the predicate).
840 if (!((Pred0 == ICmpInst::ICMP_SGT && RangeStart->isMinusOne()) ||
841 (Pred0 == ICmpInst::ICMP_SGE && RangeStart->isZero())))
844 ICmpInst::Predicate Pred1 = (Inverted ? Cmp1->getInversePredicate() :
845 Cmp1->getPredicate());
847 Value *Input = Cmp0->getOperand(0);
849 if (Cmp1->getOperand(0) == Input) {
850 // For the upper range compare we have: icmp x, n
851 RangeEnd = Cmp1->getOperand(1);
852 } else if (Cmp1->getOperand(1) == Input) {
853 // For the upper range compare we have: icmp n, x
854 RangeEnd = Cmp1->getOperand(0);
855 Pred1 = ICmpInst::getSwappedPredicate(Pred1);
860 // Check the upper range comparison, e.g. x < n
861 ICmpInst::Predicate NewPred;
863 case ICmpInst::ICMP_SLT: NewPred = ICmpInst::ICMP_ULT; break;
864 case ICmpInst::ICMP_SLE: NewPred = ICmpInst::ICMP_ULE; break;
865 default: return nullptr;
868 // This simplification is only valid if the upper range is not negative.
869 bool IsNegative, IsNotNegative;
870 ComputeSignBit(RangeEnd, IsNotNegative, IsNegative, /*Depth=*/0, Cmp1);
875 NewPred = ICmpInst::getInversePredicate(NewPred);
877 return Builder->CreateICmp(NewPred, Input, RangeEnd);
880 /// Fold (icmp)&(icmp) if possible.
881 Value *InstCombiner::FoldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
882 ICmpInst::Predicate LHSCC = LHS->getPredicate(), RHSCC = RHS->getPredicate();
884 // (icmp1 A, B) & (icmp2 A, B) --> (icmp3 A, B)
885 if (PredicatesFoldable(LHSCC, RHSCC)) {
886 if (LHS->getOperand(0) == RHS->getOperand(1) &&
887 LHS->getOperand(1) == RHS->getOperand(0))
889 if (LHS->getOperand(0) == RHS->getOperand(0) &&
890 LHS->getOperand(1) == RHS->getOperand(1)) {
891 Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1);
892 unsigned Code = getICmpCode(LHS) & getICmpCode(RHS);
893 bool isSigned = LHS->isSigned() || RHS->isSigned();
894 return getNewICmpValue(isSigned, Code, Op0, Op1, Builder);
898 // handle (roughly): (icmp eq (A & B), C) & (icmp eq (A & D), E)
899 if (Value *V = foldLogOpOfMaskedICmps(LHS, RHS, true, Builder))
902 // E.g. (icmp sge x, 0) & (icmp slt x, n) --> icmp ult x, n
903 if (Value *V = simplifyRangeCheck(LHS, RHS, /*Inverted=*/false))
906 // E.g. (icmp slt x, n) & (icmp sge x, 0) --> icmp ult x, n
907 if (Value *V = simplifyRangeCheck(RHS, LHS, /*Inverted=*/false))
910 // This only handles icmp of constants: (icmp1 A, C1) & (icmp2 B, C2).
911 Value *Val = LHS->getOperand(0), *Val2 = RHS->getOperand(0);
912 ConstantInt *LHSCst = dyn_cast<ConstantInt>(LHS->getOperand(1));
913 ConstantInt *RHSCst = dyn_cast<ConstantInt>(RHS->getOperand(1));
914 if (!LHSCst || !RHSCst) return nullptr;
916 if (LHSCst == RHSCst && LHSCC == RHSCC) {
917 // (icmp ult A, C) & (icmp ult B, C) --> (icmp ult (A|B), C)
918 // where C is a power of 2
919 if (LHSCC == ICmpInst::ICMP_ULT &&
920 LHSCst->getValue().isPowerOf2()) {
921 Value *NewOr = Builder->CreateOr(Val, Val2);
922 return Builder->CreateICmp(LHSCC, NewOr, LHSCst);
925 // (icmp eq A, 0) & (icmp eq B, 0) --> (icmp eq (A|B), 0)
926 if (LHSCC == ICmpInst::ICMP_EQ && LHSCst->isZero()) {
927 Value *NewOr = Builder->CreateOr(Val, Val2);
928 return Builder->CreateICmp(LHSCC, NewOr, LHSCst);
932 // (trunc x) == C1 & (and x, CA) == C2 -> (and x, CA|CMAX) == C1|C2
933 // where CMAX is the all ones value for the truncated type,
934 // iff the lower bits of C2 and CA are zero.
935 if (LHSCC == ICmpInst::ICMP_EQ && LHSCC == RHSCC &&
936 LHS->hasOneUse() && RHS->hasOneUse()) {
938 ConstantInt *AndCst, *SmallCst = nullptr, *BigCst = nullptr;
940 // (trunc x) == C1 & (and x, CA) == C2
941 // (and x, CA) == C2 & (trunc x) == C1
942 if (match(Val2, m_Trunc(m_Value(V))) &&
943 match(Val, m_And(m_Specific(V), m_ConstantInt(AndCst)))) {
946 } else if (match(Val, m_Trunc(m_Value(V))) &&
947 match(Val2, m_And(m_Specific(V), m_ConstantInt(AndCst)))) {
952 if (SmallCst && BigCst) {
953 unsigned BigBitSize = BigCst->getType()->getBitWidth();
954 unsigned SmallBitSize = SmallCst->getType()->getBitWidth();
956 // Check that the low bits are zero.
957 APInt Low = APInt::getLowBitsSet(BigBitSize, SmallBitSize);
958 if ((Low & AndCst->getValue()) == 0 && (Low & BigCst->getValue()) == 0) {
959 Value *NewAnd = Builder->CreateAnd(V, Low | AndCst->getValue());
960 APInt N = SmallCst->getValue().zext(BigBitSize) | BigCst->getValue();
961 Value *NewVal = ConstantInt::get(AndCst->getType()->getContext(), N);
962 return Builder->CreateICmp(LHSCC, NewAnd, NewVal);
967 // From here on, we only handle:
968 // (icmp1 A, C1) & (icmp2 A, C2) --> something simpler.
969 if (Val != Val2) return nullptr;
971 // ICMP_[US][GL]E X, CST is folded to ICMP_[US][GL]T elsewhere.
972 if (LHSCC == ICmpInst::ICMP_UGE || LHSCC == ICmpInst::ICMP_ULE ||
973 RHSCC == ICmpInst::ICMP_UGE || RHSCC == ICmpInst::ICMP_ULE ||
974 LHSCC == ICmpInst::ICMP_SGE || LHSCC == ICmpInst::ICMP_SLE ||
975 RHSCC == ICmpInst::ICMP_SGE || RHSCC == ICmpInst::ICMP_SLE)
978 // Make a constant range that's the intersection of the two icmp ranges.
979 // If the intersection is empty, we know that the result is false.
980 ConstantRange LHSRange =
981 ConstantRange::makeAllowedICmpRegion(LHSCC, LHSCst->getValue());
982 ConstantRange RHSRange =
983 ConstantRange::makeAllowedICmpRegion(RHSCC, RHSCst->getValue());
985 if (LHSRange.intersectWith(RHSRange).isEmptySet())
986 return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
988 // We can't fold (ugt x, C) & (sgt x, C2).
989 if (!PredicatesFoldable(LHSCC, RHSCC))
992 // Ensure that the larger constant is on the RHS.
994 if (CmpInst::isSigned(LHSCC) ||
995 (ICmpInst::isEquality(LHSCC) &&
996 CmpInst::isSigned(RHSCC)))
997 ShouldSwap = LHSCst->getValue().sgt(RHSCst->getValue());
999 ShouldSwap = LHSCst->getValue().ugt(RHSCst->getValue());
1002 std::swap(LHS, RHS);
1003 std::swap(LHSCst, RHSCst);
1004 std::swap(LHSCC, RHSCC);
1007 // At this point, we know we have two icmp instructions
1008 // comparing a value against two constants and and'ing the result
1009 // together. Because of the above check, we know that we only have
1010 // icmp eq, icmp ne, icmp [su]lt, and icmp [SU]gt here. We also know
1011 // (from the icmp folding check above), that the two constants
1012 // are not equal and that the larger constant is on the RHS
1013 assert(LHSCst != RHSCst && "Compares not folded above?");
1016 default: llvm_unreachable("Unknown integer condition code!");
1017 case ICmpInst::ICMP_EQ:
1019 default: llvm_unreachable("Unknown integer condition code!");
1020 case ICmpInst::ICMP_NE: // (X == 13 & X != 15) -> X == 13
1021 case ICmpInst::ICMP_ULT: // (X == 13 & X < 15) -> X == 13
1022 case ICmpInst::ICMP_SLT: // (X == 13 & X < 15) -> X == 13
1025 case ICmpInst::ICMP_NE:
1027 default: llvm_unreachable("Unknown integer condition code!");
1028 case ICmpInst::ICMP_ULT:
1029 if (LHSCst == SubOne(RHSCst)) // (X != 13 & X u< 14) -> X < 13
1030 return Builder->CreateICmpULT(Val, LHSCst);
1031 if (LHSCst->isNullValue()) // (X != 0 & X u< 14) -> X-1 u< 13
1032 return InsertRangeTest(Val, AddOne(LHSCst), RHSCst, false, true);
1033 break; // (X != 13 & X u< 15) -> no change
1034 case ICmpInst::ICMP_SLT:
1035 if (LHSCst == SubOne(RHSCst)) // (X != 13 & X s< 14) -> X < 13
1036 return Builder->CreateICmpSLT(Val, LHSCst);
1037 break; // (X != 13 & X s< 15) -> no change
1038 case ICmpInst::ICMP_EQ: // (X != 13 & X == 15) -> X == 15
1039 case ICmpInst::ICMP_UGT: // (X != 13 & X u> 15) -> X u> 15
1040 case ICmpInst::ICMP_SGT: // (X != 13 & X s> 15) -> X s> 15
1042 case ICmpInst::ICMP_NE:
1043 // Special case to get the ordering right when the values wrap around
1045 if (LHSCst->getValue() == 0 && RHSCst->getValue().isAllOnesValue())
1046 std::swap(LHSCst, RHSCst);
1047 if (LHSCst == SubOne(RHSCst)){// (X != 13 & X != 14) -> X-13 >u 1
1048 Constant *AddCST = ConstantExpr::getNeg(LHSCst);
1049 Value *Add = Builder->CreateAdd(Val, AddCST, Val->getName()+".off");
1050 return Builder->CreateICmpUGT(Add, ConstantInt::get(Add->getType(), 1),
1051 Val->getName()+".cmp");
1053 break; // (X != 13 & X != 15) -> no change
1056 case ICmpInst::ICMP_ULT:
1058 default: llvm_unreachable("Unknown integer condition code!");
1059 case ICmpInst::ICMP_EQ: // (X u< 13 & X == 15) -> false
1060 case ICmpInst::ICMP_UGT: // (X u< 13 & X u> 15) -> false
1061 return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
1062 case ICmpInst::ICMP_SGT: // (X u< 13 & X s> 15) -> no change
1064 case ICmpInst::ICMP_NE: // (X u< 13 & X != 15) -> X u< 13
1065 case ICmpInst::ICMP_ULT: // (X u< 13 & X u< 15) -> X u< 13
1067 case ICmpInst::ICMP_SLT: // (X u< 13 & X s< 15) -> no change
1071 case ICmpInst::ICMP_SLT:
1073 default: llvm_unreachable("Unknown integer condition code!");
1074 case ICmpInst::ICMP_UGT: // (X s< 13 & X u> 15) -> no change
1076 case ICmpInst::ICMP_NE: // (X s< 13 & X != 15) -> X < 13
1077 case ICmpInst::ICMP_SLT: // (X s< 13 & X s< 15) -> X < 13
1079 case ICmpInst::ICMP_ULT: // (X s< 13 & X u< 15) -> no change
1083 case ICmpInst::ICMP_UGT:
1085 default: llvm_unreachable("Unknown integer condition code!");
1086 case ICmpInst::ICMP_EQ: // (X u> 13 & X == 15) -> X == 15
1087 case ICmpInst::ICMP_UGT: // (X u> 13 & X u> 15) -> X u> 15
1089 case ICmpInst::ICMP_SGT: // (X u> 13 & X s> 15) -> no change
1091 case ICmpInst::ICMP_NE:
1092 if (RHSCst == AddOne(LHSCst)) // (X u> 13 & X != 14) -> X u> 14
1093 return Builder->CreateICmp(LHSCC, Val, RHSCst);
1094 break; // (X u> 13 & X != 15) -> no change
1095 case ICmpInst::ICMP_ULT: // (X u> 13 & X u< 15) -> (X-14) <u 1
1096 return InsertRangeTest(Val, AddOne(LHSCst), RHSCst, false, true);
1097 case ICmpInst::ICMP_SLT: // (X u> 13 & X s< 15) -> no change
1101 case ICmpInst::ICMP_SGT:
1103 default: llvm_unreachable("Unknown integer condition code!");
1104 case ICmpInst::ICMP_EQ: // (X s> 13 & X == 15) -> X == 15
1105 case ICmpInst::ICMP_SGT: // (X s> 13 & X s> 15) -> X s> 15
1107 case ICmpInst::ICMP_UGT: // (X s> 13 & X u> 15) -> no change
1109 case ICmpInst::ICMP_NE:
1110 if (RHSCst == AddOne(LHSCst)) // (X s> 13 & X != 14) -> X s> 14
1111 return Builder->CreateICmp(LHSCC, Val, RHSCst);
1112 break; // (X s> 13 & X != 15) -> no change
1113 case ICmpInst::ICMP_SLT: // (X s> 13 & X s< 15) -> (X-14) s< 1
1114 return InsertRangeTest(Val, AddOne(LHSCst), RHSCst, true, true);
1115 case ICmpInst::ICMP_ULT: // (X s> 13 & X u< 15) -> no change
1124 /// Optimize (fcmp)&(fcmp). NOTE: Unlike the rest of instcombine, this returns
1125 /// a Value which should already be inserted into the function.
1126 Value *InstCombiner::FoldAndOfFCmps(FCmpInst *LHS, FCmpInst *RHS) {
1127 if (LHS->getPredicate() == FCmpInst::FCMP_ORD &&
1128 RHS->getPredicate() == FCmpInst::FCMP_ORD) {
1129 if (LHS->getOperand(0)->getType() != RHS->getOperand(0)->getType())
1132 // (fcmp ord x, c) & (fcmp ord y, c) -> (fcmp ord x, y)
1133 if (ConstantFP *LHSC = dyn_cast<ConstantFP>(LHS->getOperand(1)))
1134 if (ConstantFP *RHSC = dyn_cast<ConstantFP>(RHS->getOperand(1))) {
1135 // If either of the constants are nans, then the whole thing returns
1137 if (LHSC->getValueAPF().isNaN() || RHSC->getValueAPF().isNaN())
1138 return Builder->getFalse();
1139 return Builder->CreateFCmpORD(LHS->getOperand(0), RHS->getOperand(0));
1142 // Handle vector zeros. This occurs because the canonical form of
1143 // "fcmp ord x,x" is "fcmp ord x, 0".
1144 if (isa<ConstantAggregateZero>(LHS->getOperand(1)) &&
1145 isa<ConstantAggregateZero>(RHS->getOperand(1)))
1146 return Builder->CreateFCmpORD(LHS->getOperand(0), RHS->getOperand(0));
1150 Value *Op0LHS = LHS->getOperand(0), *Op0RHS = LHS->getOperand(1);
1151 Value *Op1LHS = RHS->getOperand(0), *Op1RHS = RHS->getOperand(1);
1152 FCmpInst::Predicate Op0CC = LHS->getPredicate(), Op1CC = RHS->getPredicate();
1155 if (Op0LHS == Op1RHS && Op0RHS == Op1LHS) {
1156 // Swap RHS operands to match LHS.
1157 Op1CC = FCmpInst::getSwappedPredicate(Op1CC);
1158 std::swap(Op1LHS, Op1RHS);
1161 if (Op0LHS == Op1LHS && Op0RHS == Op1RHS) {
1162 // Simplify (fcmp cc0 x, y) & (fcmp cc1 x, y).
1164 return Builder->CreateFCmp((FCmpInst::Predicate)Op0CC, Op0LHS, Op0RHS);
1165 if (Op0CC == FCmpInst::FCMP_FALSE || Op1CC == FCmpInst::FCMP_FALSE)
1166 return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
1167 if (Op0CC == FCmpInst::FCMP_TRUE)
1169 if (Op1CC == FCmpInst::FCMP_TRUE)
1174 unsigned Op0Pred = getFCmpCode(Op0CC, Op0Ordered);
1175 unsigned Op1Pred = getFCmpCode(Op1CC, Op1Ordered);
1176 // uno && ord -> false
1177 if (Op0Pred == 0 && Op1Pred == 0 && Op0Ordered != Op1Ordered)
1178 return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
1180 std::swap(LHS, RHS);
1181 std::swap(Op0Pred, Op1Pred);
1182 std::swap(Op0Ordered, Op1Ordered);
1185 // uno && ueq -> uno && (uno || eq) -> uno
1186 // ord && olt -> ord && (ord && lt) -> olt
1187 if (!Op0Ordered && (Op0Ordered == Op1Ordered))
1189 if (Op0Ordered && (Op0Ordered == Op1Ordered))
1192 // uno && oeq -> uno && (ord && eq) -> false
1194 return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
1195 // ord && ueq -> ord && (uno || eq) -> oeq
1196 return getFCmpValue(true, Op1Pred, Op0LHS, Op0RHS, Builder);
1203 /// Match De Morgan's Laws:
1204 /// (~A & ~B) == (~(A | B))
1205 /// (~A | ~B) == (~(A & B))
1206 static Instruction *matchDeMorgansLaws(BinaryOperator &I,
1207 InstCombiner::BuilderTy *Builder) {
1208 auto Opcode = I.getOpcode();
1209 assert((Opcode == Instruction::And || Opcode == Instruction::Or) &&
1210 "Trying to match De Morgan's Laws with something other than and/or");
1211 // Flip the logic operation.
1212 if (Opcode == Instruction::And)
1213 Opcode = Instruction::Or;
1215 Opcode = Instruction::And;
1217 Value *Op0 = I.getOperand(0);
1218 Value *Op1 = I.getOperand(1);
1219 // TODO: Use pattern matchers instead of dyn_cast.
1220 if (Value *Op0NotVal = dyn_castNotVal(Op0))
1221 if (Value *Op1NotVal = dyn_castNotVal(Op1))
1222 if (Op0->hasOneUse() && Op1->hasOneUse()) {
1223 Value *LogicOp = Builder->CreateBinOp(Opcode, Op0NotVal, Op1NotVal,
1224 I.getName() + ".demorgan");
1225 return BinaryOperator::CreateNot(LogicOp);
1228 // De Morgan's Law in disguise:
1229 // (zext(bool A) ^ 1) & (zext(bool B) ^ 1) -> zext(~(A | B))
1230 // (zext(bool A) ^ 1) | (zext(bool B) ^ 1) -> zext(~(A & B))
1233 ConstantInt *C1 = nullptr;
1234 if (match(Op0, m_OneUse(m_Xor(m_ZExt(m_Value(A)), m_ConstantInt(C1)))) &&
1235 match(Op1, m_OneUse(m_Xor(m_ZExt(m_Value(B)), m_Specific(C1))))) {
1236 // TODO: This check could be loosened to handle different type sizes.
1237 // Alternatively, we could fix the definition of m_Not to recognize a not
1238 // operation hidden by a zext?
1239 if (A->getType()->isIntegerTy(1) && B->getType()->isIntegerTy(1) &&
1241 Value *LogicOp = Builder->CreateBinOp(Opcode, A, B,
1242 I.getName() + ".demorgan");
1243 Value *Not = Builder->CreateNot(LogicOp);
1244 return CastInst::CreateZExtOrBitCast(Not, I.getType());
1251 Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
1252 bool Changed = SimplifyAssociativeOrCommutative(I);
1253 Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
1255 if (Value *V = SimplifyVectorOp(I))
1256 return ReplaceInstUsesWith(I, V);
1258 if (Value *V = SimplifyAndInst(Op0, Op1, DL, TLI, DT, AC))
1259 return ReplaceInstUsesWith(I, V);
1261 // (A|B)&(A|C) -> A|(B&C) etc
1262 if (Value *V = SimplifyUsingDistributiveLaws(I))
1263 return ReplaceInstUsesWith(I, V);
1265 // See if we can simplify any instructions used by the instruction whose sole
1266 // purpose is to compute bits we don't care about.
1267 if (SimplifyDemandedInstructionBits(I))
1270 if (Value *V = SimplifyBSwap(I))
1271 return ReplaceInstUsesWith(I, V);
1273 if (ConstantInt *AndRHS = dyn_cast<ConstantInt>(Op1)) {
1274 const APInt &AndRHSMask = AndRHS->getValue();
1276 // Optimize a variety of ((val OP C1) & C2) combinations...
1277 if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
1278 Value *Op0LHS = Op0I->getOperand(0);
1279 Value *Op0RHS = Op0I->getOperand(1);
1280 switch (Op0I->getOpcode()) {
1282 case Instruction::Xor:
1283 case Instruction::Or: {
1284 // If the mask is only needed on one incoming arm, push it up.
1285 if (!Op0I->hasOneUse()) break;
1287 APInt NotAndRHS(~AndRHSMask);
1288 if (MaskedValueIsZero(Op0LHS, NotAndRHS, 0, &I)) {
1289 // Not masking anything out for the LHS, move to RHS.
1290 Value *NewRHS = Builder->CreateAnd(Op0RHS, AndRHS,
1291 Op0RHS->getName()+".masked");
1292 return BinaryOperator::Create(Op0I->getOpcode(), Op0LHS, NewRHS);
1294 if (!isa<Constant>(Op0RHS) &&
1295 MaskedValueIsZero(Op0RHS, NotAndRHS, 0, &I)) {
1296 // Not masking anything out for the RHS, move to LHS.
1297 Value *NewLHS = Builder->CreateAnd(Op0LHS, AndRHS,
1298 Op0LHS->getName()+".masked");
1299 return BinaryOperator::Create(Op0I->getOpcode(), NewLHS, Op0RHS);
1304 case Instruction::Add:
1305 // ((A & N) + B) & AndRHS -> (A + B) & AndRHS iff N&AndRHS == AndRHS.
1306 // ((A | N) + B) & AndRHS -> (A + B) & AndRHS iff N&AndRHS == 0
1307 // ((A ^ N) + B) & AndRHS -> (A + B) & AndRHS iff N&AndRHS == 0
1308 if (Value *V = FoldLogicalPlusAnd(Op0LHS, Op0RHS, AndRHS, false, I))
1309 return BinaryOperator::CreateAnd(V, AndRHS);
1310 if (Value *V = FoldLogicalPlusAnd(Op0RHS, Op0LHS, AndRHS, false, I))
1311 return BinaryOperator::CreateAnd(V, AndRHS); // Add commutes
1314 case Instruction::Sub:
1315 // ((A & N) - B) & AndRHS -> (A - B) & AndRHS iff N&AndRHS == AndRHS.
1316 // ((A | N) - B) & AndRHS -> (A - B) & AndRHS iff N&AndRHS == 0
1317 // ((A ^ N) - B) & AndRHS -> (A - B) & AndRHS iff N&AndRHS == 0
1318 if (Value *V = FoldLogicalPlusAnd(Op0LHS, Op0RHS, AndRHS, true, I))
1319 return BinaryOperator::CreateAnd(V, AndRHS);
1322 if (AndRHSMask == 1 && match(Op0LHS, m_Zero()))
1323 return BinaryOperator::CreateAnd(Op0RHS, AndRHS);
1325 // (A - N) & AndRHS -> -N & AndRHS iff A&AndRHS==0 and AndRHS
1326 // has 1's for all bits that the subtraction with A might affect.
1327 if (Op0I->hasOneUse() && !match(Op0LHS, m_Zero())) {
1328 uint32_t BitWidth = AndRHSMask.getBitWidth();
1329 uint32_t Zeros = AndRHSMask.countLeadingZeros();
1330 APInt Mask = APInt::getLowBitsSet(BitWidth, BitWidth - Zeros);
1332 if (MaskedValueIsZero(Op0LHS, Mask, 0, &I)) {
1333 Value *NewNeg = Builder->CreateNeg(Op0RHS);
1334 return BinaryOperator::CreateAnd(NewNeg, AndRHS);
1339 case Instruction::Shl:
1340 case Instruction::LShr:
1341 // (1 << x) & 1 --> zext(x == 0)
1342 // (1 >> x) & 1 --> zext(x == 0)
1343 if (AndRHSMask == 1 && Op0LHS == AndRHS) {
1345 Builder->CreateICmpEQ(Op0RHS, Constant::getNullValue(I.getType()));
1346 return new ZExtInst(NewICmp, I.getType());
1351 if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1)))
1352 if (Instruction *Res = OptAndOp(Op0I, Op0CI, AndRHS, I))
1356 // If this is an integer truncation, and if the source is an 'and' with
1357 // immediate, transform it. This frequently occurs for bitfield accesses.
1359 Value *X = nullptr; ConstantInt *YC = nullptr;
1360 if (match(Op0, m_Trunc(m_And(m_Value(X), m_ConstantInt(YC))))) {
1361 // Change: and (trunc (and X, YC) to T), C2
1362 // into : and (trunc X to T), trunc(YC) & C2
1363 // This will fold the two constants together, which may allow
1364 // other simplifications.
1365 Value *NewCast = Builder->CreateTrunc(X, I.getType(), "and.shrunk");
1366 Constant *C3 = ConstantExpr::getTrunc(YC, I.getType());
1367 C3 = ConstantExpr::getAnd(C3, AndRHS);
1368 return BinaryOperator::CreateAnd(NewCast, C3);
1372 // Try to fold constant and into select arguments.
1373 if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
1374 if (Instruction *R = FoldOpIntoSelect(I, SI))
1376 if (isa<PHINode>(Op0))
1377 if (Instruction *NV = FoldOpIntoPhi(I))
1381 if (Instruction *DeMorgan = matchDeMorgansLaws(I, Builder))
1385 Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
1386 // (A|B) & ~(A&B) -> A^B
1387 if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
1388 match(Op1, m_Not(m_And(m_Value(C), m_Value(D)))) &&
1389 ((A == C && B == D) || (A == D && B == C)))
1390 return BinaryOperator::CreateXor(A, B);
1392 // ~(A&B) & (A|B) -> A^B
1393 if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
1394 match(Op0, m_Not(m_And(m_Value(C), m_Value(D)))) &&
1395 ((A == C && B == D) || (A == D && B == C)))
1396 return BinaryOperator::CreateXor(A, B);
1398 // A&(A^B) => A & ~B
1400 Value *tmpOp0 = Op0;
1401 Value *tmpOp1 = Op1;
1402 if (Op0->hasOneUse() &&
1403 match(Op0, m_Xor(m_Value(A), m_Value(B)))) {
1404 if (A == Op1 || B == Op1 ) {
1411 if (tmpOp1->hasOneUse() &&
1412 match(tmpOp1, m_Xor(m_Value(A), m_Value(B)))) {
1416 // Notice that the patten (A&(~B)) is actually (A&(-1^B)), so if
1417 // A is originally -1 (or a vector of -1 and undefs), then we enter
1418 // an endless loop. By checking that A is non-constant we ensure that
1419 // we will never get to the loop.
1420 if (A == tmpOp0 && !isa<Constant>(A)) // A&(A^B) -> A & ~B
1421 return BinaryOperator::CreateAnd(A, Builder->CreateNot(B));
1425 // (A&((~A)|B)) -> A&B
1426 if (match(Op0, m_Or(m_Not(m_Specific(Op1)), m_Value(A))) ||
1427 match(Op0, m_Or(m_Value(A), m_Not(m_Specific(Op1)))))
1428 return BinaryOperator::CreateAnd(A, Op1);
1429 if (match(Op1, m_Or(m_Not(m_Specific(Op0)), m_Value(A))) ||
1430 match(Op1, m_Or(m_Value(A), m_Not(m_Specific(Op0)))))
1431 return BinaryOperator::CreateAnd(A, Op0);
1433 // (A ^ B) & ((B ^ C) ^ A) -> (A ^ B) & ~C
1434 if (match(Op0, m_Xor(m_Value(A), m_Value(B))))
1435 if (match(Op1, m_Xor(m_Xor(m_Specific(B), m_Value(C)), m_Specific(A))))
1436 if (Op1->hasOneUse() || cast<BinaryOperator>(Op1)->hasOneUse())
1437 return BinaryOperator::CreateAnd(Op0, Builder->CreateNot(C));
1439 // ((A ^ C) ^ B) & (B ^ A) -> (B ^ A) & ~C
1440 if (match(Op0, m_Xor(m_Xor(m_Value(A), m_Value(C)), m_Value(B))))
1441 if (match(Op1, m_Xor(m_Specific(B), m_Specific(A))))
1442 if (Op0->hasOneUse() || cast<BinaryOperator>(Op0)->hasOneUse())
1443 return BinaryOperator::CreateAnd(Op1, Builder->CreateNot(C));
1445 // (A | B) & ((~A) ^ B) -> (A & B)
1446 if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
1447 match(Op1, m_Xor(m_Not(m_Specific(A)), m_Specific(B))))
1448 return BinaryOperator::CreateAnd(A, B);
1450 // ((~A) ^ B) & (A | B) -> (A & B)
1451 if (match(Op0, m_Xor(m_Not(m_Value(A)), m_Value(B))) &&
1452 match(Op1, m_Or(m_Specific(A), m_Specific(B))))
1453 return BinaryOperator::CreateAnd(A, B);
1457 ICmpInst *LHS = dyn_cast<ICmpInst>(Op0);
1458 ICmpInst *RHS = dyn_cast<ICmpInst>(Op1);
1460 if (Value *Res = FoldAndOfICmps(LHS, RHS))
1461 return ReplaceInstUsesWith(I, Res);
1463 // TODO: Make this recursive; it's a little tricky because an arbitrary
1464 // number of 'and' instructions might have to be created.
1466 if (LHS && match(Op1, m_OneUse(m_And(m_Value(X), m_Value(Y))))) {
1467 if (auto *Cmp = dyn_cast<ICmpInst>(X))
1468 if (Value *Res = FoldAndOfICmps(LHS, Cmp))
1469 return ReplaceInstUsesWith(I, Builder->CreateAnd(Res, Y));
1470 if (auto *Cmp = dyn_cast<ICmpInst>(Y))
1471 if (Value *Res = FoldAndOfICmps(LHS, Cmp))
1472 return ReplaceInstUsesWith(I, Builder->CreateAnd(Res, X));
1474 if (RHS && match(Op0, m_OneUse(m_And(m_Value(X), m_Value(Y))))) {
1475 if (auto *Cmp = dyn_cast<ICmpInst>(X))
1476 if (Value *Res = FoldAndOfICmps(Cmp, RHS))
1477 return ReplaceInstUsesWith(I, Builder->CreateAnd(Res, Y));
1478 if (auto *Cmp = dyn_cast<ICmpInst>(Y))
1479 if (Value *Res = FoldAndOfICmps(Cmp, RHS))
1480 return ReplaceInstUsesWith(I, Builder->CreateAnd(Res, X));
1484 // If and'ing two fcmp, try combine them into one.
1485 if (FCmpInst *LHS = dyn_cast<FCmpInst>(I.getOperand(0)))
1486 if (FCmpInst *RHS = dyn_cast<FCmpInst>(I.getOperand(1)))
1487 if (Value *Res = FoldAndOfFCmps(LHS, RHS))
1488 return ReplaceInstUsesWith(I, Res);
1491 if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
1492 Value *Op0COp = Op0C->getOperand(0);
1493 Type *SrcTy = Op0COp->getType();
1494 // fold (and (cast A), (cast B)) -> (cast (and A, B))
1495 if (CastInst *Op1C = dyn_cast<CastInst>(Op1)) {
1496 if (Op0C->getOpcode() == Op1C->getOpcode() && // same cast kind ?
1497 SrcTy == Op1C->getOperand(0)->getType() &&
1498 SrcTy->isIntOrIntVectorTy()) {
1499 Value *Op1COp = Op1C->getOperand(0);
1501 // Only do this if the casts both really cause code to be generated.
1502 if (ShouldOptimizeCast(Op0C->getOpcode(), Op0COp, I.getType()) &&
1503 ShouldOptimizeCast(Op1C->getOpcode(), Op1COp, I.getType())) {
1504 Value *NewOp = Builder->CreateAnd(Op0COp, Op1COp, I.getName());
1505 return CastInst::Create(Op0C->getOpcode(), NewOp, I.getType());
1508 // If this is and(cast(icmp), cast(icmp)), try to fold this even if the
1509 // cast is otherwise not optimizable. This happens for vector sexts.
1510 if (ICmpInst *RHS = dyn_cast<ICmpInst>(Op1COp))
1511 if (ICmpInst *LHS = dyn_cast<ICmpInst>(Op0COp))
1512 if (Value *Res = FoldAndOfICmps(LHS, RHS))
1513 return CastInst::Create(Op0C->getOpcode(), Res, I.getType());
1515 // If this is and(cast(fcmp), cast(fcmp)), try to fold this even if the
1516 // cast is otherwise not optimizable. This happens for vector sexts.
1517 if (FCmpInst *RHS = dyn_cast<FCmpInst>(Op1COp))
1518 if (FCmpInst *LHS = dyn_cast<FCmpInst>(Op0COp))
1519 if (Value *Res = FoldAndOfFCmps(LHS, RHS))
1520 return CastInst::Create(Op0C->getOpcode(), Res, I.getType());
1524 // If we are masking off the sign bit of a floating-point value, convert
1525 // this to the canonical fabs intrinsic call and cast back to integer.
1526 // The backend should know how to optimize fabs().
1527 // TODO: This transform should also apply to vectors.
1529 if (isa<BitCastInst>(Op0C) && SrcTy->isFloatingPointTy() &&
1530 match(Op1, m_ConstantInt(CI)) && CI->isMaxValue(true)) {
1531 Module *M = I.getParent()->getParent()->getParent();
1532 Function *Fabs = Intrinsic::getDeclaration(M, Intrinsic::fabs, SrcTy);
1533 Value *Call = Builder->CreateCall(Fabs, Op0COp, "fabs");
1534 return CastInst::CreateBitOrPointerCast(Call, I.getType());
1540 bool OpsSwapped = false;
1541 // Canonicalize SExt or Not to the LHS
1542 if (match(Op1, m_SExt(m_Value())) ||
1543 match(Op1, m_Not(m_Value()))) {
1544 std::swap(Op0, Op1);
1548 // Fold (and (sext bool to A), B) --> (select bool, B, 0)
1549 if (match(Op0, m_SExt(m_Value(X))) &&
1550 X->getType()->getScalarType()->isIntegerTy(1)) {
1551 Value *Zero = Constant::getNullValue(Op1->getType());
1552 return SelectInst::Create(X, Op1, Zero);
1555 // Fold (and ~(sext bool to A), B) --> (select bool, 0, B)
1556 if (match(Op0, m_Not(m_SExt(m_Value(X)))) &&
1557 X->getType()->getScalarType()->isIntegerTy(1)) {
1558 Value *Zero = Constant::getNullValue(Op0->getType());
1559 return SelectInst::Create(X, Zero, Op1);
1563 std::swap(Op0, Op1);
1566 return Changed ? &I : nullptr;
1569 /// Analyze the specified subexpression and see if it is capable of providing
1570 /// pieces of a bswap. The subexpression provides pieces of a bswap if it is
1571 /// proven that each of the non-zero bytes in the output of the expression came
1572 /// from the corresponding "byte swapped" byte in some other value.
1573 /// For example, if the current subexpression is "(shl i32 %X, 24)" then
1574 /// we know that the expression deposits the low byte of %X into the high byte
1575 /// of the bswap result and that all other bytes are zero. This expression is
1576 /// accepted, the high byte of ByteValues is set to X to indicate a correct
1579 /// This function returns true if the match was unsuccessful and false if so.
1580 /// On entry to the function the "OverallLeftShift" is a signed integer value
1581 /// indicating the number of bytes that the subexpression is later shifted. For
1582 /// example, if the expression is later right shifted by 16 bits, the
1583 /// OverallLeftShift value would be -2 on entry. This is used to specify which
1584 /// byte of ByteValues is actually being set.
1586 /// Similarly, ByteMask is a bitmask where a bit is clear if its corresponding
1587 /// byte is masked to zero by a user. For example, in (X & 255), X will be
1588 /// processed with a bytemask of 1. Because bytemask is 32-bits, this limits
1589 /// this function to working on up to 32-byte (256 bit) values. ByteMask is
1590 /// always in the local (OverallLeftShift) coordinate space.
1592 static bool CollectBSwapParts(Value *V, int OverallLeftShift, uint32_t ByteMask,
1593 SmallVectorImpl<Value *> &ByteValues) {
1594 if (Instruction *I = dyn_cast<Instruction>(V)) {
1595 // If this is an or instruction, it may be an inner node of the bswap.
1596 if (I->getOpcode() == Instruction::Or) {
1597 return CollectBSwapParts(I->getOperand(0), OverallLeftShift, ByteMask,
1599 CollectBSwapParts(I->getOperand(1), OverallLeftShift, ByteMask,
1603 // If this is a logical shift by a constant multiple of 8, recurse with
1604 // OverallLeftShift and ByteMask adjusted.
1605 if (I->isLogicalShift() && isa<ConstantInt>(I->getOperand(1))) {
1607 cast<ConstantInt>(I->getOperand(1))->getLimitedValue(~0U);
1608 // Ensure the shift amount is defined and of a byte value.
1609 if ((ShAmt & 7) || (ShAmt > 8*ByteValues.size()))
1612 unsigned ByteShift = ShAmt >> 3;
1613 if (I->getOpcode() == Instruction::Shl) {
1614 // X << 2 -> collect(X, +2)
1615 OverallLeftShift += ByteShift;
1616 ByteMask >>= ByteShift;
1618 // X >>u 2 -> collect(X, -2)
1619 OverallLeftShift -= ByteShift;
1620 ByteMask <<= ByteShift;
1621 ByteMask &= (~0U >> (32-ByteValues.size()));
1624 if (OverallLeftShift >= (int)ByteValues.size()) return true;
1625 if (OverallLeftShift <= -(int)ByteValues.size()) return true;
1627 return CollectBSwapParts(I->getOperand(0), OverallLeftShift, ByteMask,
1631 // If this is a logical 'and' with a mask that clears bytes, clear the
1632 // corresponding bytes in ByteMask.
1633 if (I->getOpcode() == Instruction::And &&
1634 isa<ConstantInt>(I->getOperand(1))) {
1635 // Scan every byte of the and mask, seeing if the byte is either 0 or 255.
1636 unsigned NumBytes = ByteValues.size();
1637 APInt Byte(I->getType()->getPrimitiveSizeInBits(), 255);
1638 const APInt &AndMask = cast<ConstantInt>(I->getOperand(1))->getValue();
1640 for (unsigned i = 0; i != NumBytes; ++i, Byte <<= 8) {
1641 // If this byte is masked out by a later operation, we don't care what
1643 if ((ByteMask & (1 << i)) == 0)
1646 // If the AndMask is all zeros for this byte, clear the bit.
1647 APInt MaskB = AndMask & Byte;
1649 ByteMask &= ~(1U << i);
1653 // If the AndMask is not all ones for this byte, it's not a bytezap.
1657 // Otherwise, this byte is kept.
1660 return CollectBSwapParts(I->getOperand(0), OverallLeftShift, ByteMask,
1665 // Okay, we got to something that isn't a shift, 'or' or 'and'. This must be
1666 // the input value to the bswap. Some observations: 1) if more than one byte
1667 // is demanded from this input, then it could not be successfully assembled
1668 // into a byteswap. At least one of the two bytes would not be aligned with
1669 // their ultimate destination.
1670 if (!isPowerOf2_32(ByteMask)) return true;
1671 unsigned InputByteNo = countTrailingZeros(ByteMask);
1673 // 2) The input and ultimate destinations must line up: if byte 3 of an i32
1674 // is demanded, it needs to go into byte 0 of the result. This means that the
1675 // byte needs to be shifted until it lands in the right byte bucket. The
1676 // shift amount depends on the position: if the byte is coming from the high
1677 // part of the value (e.g. byte 3) then it must be shifted right. If from the
1678 // low part, it must be shifted left.
1679 unsigned DestByteNo = InputByteNo + OverallLeftShift;
1680 if (ByteValues.size()-1-DestByteNo != InputByteNo)
1683 // If the destination byte value is already defined, the values are or'd
1684 // together, which isn't a bswap (unless it's an or of the same bits).
1685 if (ByteValues[DestByteNo] && ByteValues[DestByteNo] != V)
1687 ByteValues[DestByteNo] = V;
1691 /// Given an OR instruction, check to see if this is a bswap idiom.
1692 /// If so, insert the new bswap intrinsic and return it.
1693 Instruction *InstCombiner::MatchBSwap(BinaryOperator &I) {
1694 IntegerType *ITy = dyn_cast<IntegerType>(I.getType());
1695 if (!ITy || ITy->getBitWidth() % 16 ||
1696 // ByteMask only allows up to 32-byte values.
1697 ITy->getBitWidth() > 32*8)
1698 return nullptr; // Can only bswap pairs of bytes. Can't do vectors.
1700 /// ByteValues - For each byte of the result, we keep track of which value
1701 /// defines each byte.
1702 SmallVector<Value*, 8> ByteValues;
1703 ByteValues.resize(ITy->getBitWidth()/8);
1705 // Try to find all the pieces corresponding to the bswap.
1706 uint32_t ByteMask = ~0U >> (32-ByteValues.size());
1707 if (CollectBSwapParts(&I, 0, ByteMask, ByteValues))
1710 // Check to see if all of the bytes come from the same value.
1711 Value *V = ByteValues[0];
1712 if (!V) return nullptr; // Didn't find a byte? Must be zero.
1714 // Check to make sure that all of the bytes come from the same value.
1715 for (unsigned i = 1, e = ByteValues.size(); i != e; ++i)
1716 if (ByteValues[i] != V)
1718 Module *M = I.getParent()->getParent()->getParent();
1719 Function *F = Intrinsic::getDeclaration(M, Intrinsic::bswap, ITy);
1720 return CallInst::Create(F, V);
1723 /// We have an expression of the form (A&C)|(B&D). Check if A is (cond?-1:0)
1724 /// and either B or D is ~(cond?-1,0) or (cond?0,-1), then we can simplify this
1725 /// expression to "cond ? C : D or B".
1726 static Instruction *MatchSelectFromAndOr(Value *A, Value *B,
1727 Value *C, Value *D) {
1728 // If A is not a select of -1/0, this cannot match.
1729 Value *Cond = nullptr;
1730 if (!match(A, m_SExt(m_Value(Cond))) ||
1731 !Cond->getType()->isIntegerTy(1))
1734 // ((cond?-1:0)&C) | (B&(cond?0:-1)) -> cond ? C : B.
1735 if (match(D, m_Not(m_SExt(m_Specific(Cond)))))
1736 return SelectInst::Create(Cond, C, B);
1737 if (match(D, m_SExt(m_Not(m_Specific(Cond)))))
1738 return SelectInst::Create(Cond, C, B);
1740 // ((cond?-1:0)&C) | ((cond?0:-1)&D) -> cond ? C : D.
1741 if (match(B, m_Not(m_SExt(m_Specific(Cond)))))
1742 return SelectInst::Create(Cond, C, D);
1743 if (match(B, m_SExt(m_Not(m_Specific(Cond)))))
1744 return SelectInst::Create(Cond, C, D);
1748 /// Fold (icmp)|(icmp) if possible.
1749 Value *InstCombiner::FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS,
1750 Instruction *CxtI) {
1751 ICmpInst::Predicate LHSCC = LHS->getPredicate(), RHSCC = RHS->getPredicate();
1753 // Fold (iszero(A & K1) | iszero(A & K2)) -> (A & (K1 | K2)) != (K1 | K2)
1754 // if K1 and K2 are a one-bit mask.
1755 ConstantInt *LHSCst = dyn_cast<ConstantInt>(LHS->getOperand(1));
1756 ConstantInt *RHSCst = dyn_cast<ConstantInt>(RHS->getOperand(1));
1758 if (LHS->getPredicate() == ICmpInst::ICMP_EQ && LHSCst && LHSCst->isZero() &&
1759 RHS->getPredicate() == ICmpInst::ICMP_EQ && RHSCst && RHSCst->isZero()) {
1761 BinaryOperator *LAnd = dyn_cast<BinaryOperator>(LHS->getOperand(0));
1762 BinaryOperator *RAnd = dyn_cast<BinaryOperator>(RHS->getOperand(0));
1763 if (LAnd && RAnd && LAnd->hasOneUse() && RHS->hasOneUse() &&
1764 LAnd->getOpcode() == Instruction::And &&
1765 RAnd->getOpcode() == Instruction::And) {
1767 Value *Mask = nullptr;
1768 Value *Masked = nullptr;
1769 if (LAnd->getOperand(0) == RAnd->getOperand(0) &&
1770 isKnownToBeAPowerOfTwo(LAnd->getOperand(1), DL, false, 0, AC, CxtI,
1772 isKnownToBeAPowerOfTwo(RAnd->getOperand(1), DL, false, 0, AC, CxtI,
1774 Mask = Builder->CreateOr(LAnd->getOperand(1), RAnd->getOperand(1));
1775 Masked = Builder->CreateAnd(LAnd->getOperand(0), Mask);
1776 } else if (LAnd->getOperand(1) == RAnd->getOperand(1) &&
1777 isKnownToBeAPowerOfTwo(LAnd->getOperand(0), DL, false, 0, AC,
1779 isKnownToBeAPowerOfTwo(RAnd->getOperand(0), DL, false, 0, AC,
1781 Mask = Builder->CreateOr(LAnd->getOperand(0), RAnd->getOperand(0));
1782 Masked = Builder->CreateAnd(LAnd->getOperand(1), Mask);
1786 return Builder->CreateICmp(ICmpInst::ICMP_NE, Masked, Mask);
1790 // Fold (icmp ult/ule (A + C1), C3) | (icmp ult/ule (A + C2), C3)
1791 // --> (icmp ult/ule ((A & ~(C1 ^ C2)) + max(C1, C2)), C3)
1792 // The original condition actually refers to the following two ranges:
1793 // [MAX_UINT-C1+1, MAX_UINT-C1+1+C3] and [MAX_UINT-C2+1, MAX_UINT-C2+1+C3]
1794 // We can fold these two ranges if:
1795 // 1) C1 and C2 is unsigned greater than C3.
1796 // 2) The two ranges are separated.
1797 // 3) C1 ^ C2 is one-bit mask.
1798 // 4) LowRange1 ^ LowRange2 and HighRange1 ^ HighRange2 are one-bit mask.
1799 // This implies all values in the two ranges differ by exactly one bit.
1801 if ((LHSCC == ICmpInst::ICMP_ULT || LHSCC == ICmpInst::ICMP_ULE) &&
1802 LHSCC == RHSCC && LHSCst && RHSCst && LHS->hasOneUse() &&
1803 RHS->hasOneUse() && LHSCst->getType() == RHSCst->getType() &&
1804 LHSCst->getValue() == (RHSCst->getValue())) {
1806 Value *LAdd = LHS->getOperand(0);
1807 Value *RAdd = RHS->getOperand(0);
1809 Value *LAddOpnd, *RAddOpnd;
1810 ConstantInt *LAddCst, *RAddCst;
1811 if (match(LAdd, m_Add(m_Value(LAddOpnd), m_ConstantInt(LAddCst))) &&
1812 match(RAdd, m_Add(m_Value(RAddOpnd), m_ConstantInt(RAddCst))) &&
1813 LAddCst->getValue().ugt(LHSCst->getValue()) &&
1814 RAddCst->getValue().ugt(LHSCst->getValue())) {
1816 APInt DiffCst = LAddCst->getValue() ^ RAddCst->getValue();
1817 if (LAddOpnd == RAddOpnd && DiffCst.isPowerOf2()) {
1818 ConstantInt *MaxAddCst = nullptr;
1819 if (LAddCst->getValue().ult(RAddCst->getValue()))
1820 MaxAddCst = RAddCst;
1822 MaxAddCst = LAddCst;
1824 APInt RRangeLow = -RAddCst->getValue();
1825 APInt RRangeHigh = RRangeLow + LHSCst->getValue();
1826 APInt LRangeLow = -LAddCst->getValue();
1827 APInt LRangeHigh = LRangeLow + LHSCst->getValue();
1828 APInt LowRangeDiff = RRangeLow ^ LRangeLow;
1829 APInt HighRangeDiff = RRangeHigh ^ LRangeHigh;
1830 APInt RangeDiff = LRangeLow.sgt(RRangeLow) ? LRangeLow - RRangeLow
1831 : RRangeLow - LRangeLow;
1833 if (LowRangeDiff.isPowerOf2() && LowRangeDiff == HighRangeDiff &&
1834 RangeDiff.ugt(LHSCst->getValue())) {
1835 Value *MaskCst = ConstantInt::get(LAddCst->getType(), ~DiffCst);
1837 Value *NewAnd = Builder->CreateAnd(LAddOpnd, MaskCst);
1838 Value *NewAdd = Builder->CreateAdd(NewAnd, MaxAddCst);
1839 return (Builder->CreateICmp(LHS->getPredicate(), NewAdd, LHSCst));
1845 // (icmp1 A, B) | (icmp2 A, B) --> (icmp3 A, B)
1846 if (PredicatesFoldable(LHSCC, RHSCC)) {
1847 if (LHS->getOperand(0) == RHS->getOperand(1) &&
1848 LHS->getOperand(1) == RHS->getOperand(0))
1849 LHS->swapOperands();
1850 if (LHS->getOperand(0) == RHS->getOperand(0) &&
1851 LHS->getOperand(1) == RHS->getOperand(1)) {
1852 Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1);
1853 unsigned Code = getICmpCode(LHS) | getICmpCode(RHS);
1854 bool isSigned = LHS->isSigned() || RHS->isSigned();
1855 return getNewICmpValue(isSigned, Code, Op0, Op1, Builder);
1859 // handle (roughly):
1860 // (icmp ne (A & B), C) | (icmp ne (A & D), E)
1861 if (Value *V = foldLogOpOfMaskedICmps(LHS, RHS, false, Builder))
1864 Value *Val = LHS->getOperand(0), *Val2 = RHS->getOperand(0);
1865 if (LHS->hasOneUse() || RHS->hasOneUse()) {
1866 // (icmp eq B, 0) | (icmp ult A, B) -> (icmp ule A, B-1)
1867 // (icmp eq B, 0) | (icmp ugt B, A) -> (icmp ule A, B-1)
1868 Value *A = nullptr, *B = nullptr;
1869 if (LHSCC == ICmpInst::ICMP_EQ && LHSCst && LHSCst->isZero()) {
1871 if (RHSCC == ICmpInst::ICMP_ULT && Val == RHS->getOperand(1))
1873 else if (RHSCC == ICmpInst::ICMP_UGT && Val == Val2)
1874 A = RHS->getOperand(1);
1876 // (icmp ult A, B) | (icmp eq B, 0) -> (icmp ule A, B-1)
1877 // (icmp ugt B, A) | (icmp eq B, 0) -> (icmp ule A, B-1)
1878 else if (RHSCC == ICmpInst::ICMP_EQ && RHSCst && RHSCst->isZero()) {
1880 if (LHSCC == ICmpInst::ICMP_ULT && Val2 == LHS->getOperand(1))
1882 else if (LHSCC == ICmpInst::ICMP_UGT && Val2 == Val)
1883 A = LHS->getOperand(1);
1886 return Builder->CreateICmp(
1888 Builder->CreateAdd(B, ConstantInt::getSigned(B->getType(), -1)), A);
1891 // E.g. (icmp slt x, 0) | (icmp sgt x, n) --> icmp ugt x, n
1892 if (Value *V = simplifyRangeCheck(LHS, RHS, /*Inverted=*/true))
1895 // E.g. (icmp sgt x, n) | (icmp slt x, 0) --> icmp ugt x, n
1896 if (Value *V = simplifyRangeCheck(RHS, LHS, /*Inverted=*/true))
1899 // This only handles icmp of constants: (icmp1 A, C1) | (icmp2 B, C2).
1900 if (!LHSCst || !RHSCst) return nullptr;
1902 if (LHSCst == RHSCst && LHSCC == RHSCC) {
1903 // (icmp ne A, 0) | (icmp ne B, 0) --> (icmp ne (A|B), 0)
1904 if (LHSCC == ICmpInst::ICMP_NE && LHSCst->isZero()) {
1905 Value *NewOr = Builder->CreateOr(Val, Val2);
1906 return Builder->CreateICmp(LHSCC, NewOr, LHSCst);
1910 // (icmp ult (X + CA), C1) | (icmp eq X, C2) -> (icmp ule (X + CA), C1)
1911 // iff C2 + CA == C1.
1912 if (LHSCC == ICmpInst::ICMP_ULT && RHSCC == ICmpInst::ICMP_EQ) {
1913 ConstantInt *AddCst;
1914 if (match(Val, m_Add(m_Specific(Val2), m_ConstantInt(AddCst))))
1915 if (RHSCst->getValue() + AddCst->getValue() == LHSCst->getValue())
1916 return Builder->CreateICmpULE(Val, LHSCst);
1919 // From here on, we only handle:
1920 // (icmp1 A, C1) | (icmp2 A, C2) --> something simpler.
1921 if (Val != Val2) return nullptr;
1923 // ICMP_[US][GL]E X, CST is folded to ICMP_[US][GL]T elsewhere.
1924 if (LHSCC == ICmpInst::ICMP_UGE || LHSCC == ICmpInst::ICMP_ULE ||
1925 RHSCC == ICmpInst::ICMP_UGE || RHSCC == ICmpInst::ICMP_ULE ||
1926 LHSCC == ICmpInst::ICMP_SGE || LHSCC == ICmpInst::ICMP_SLE ||
1927 RHSCC == ICmpInst::ICMP_SGE || RHSCC == ICmpInst::ICMP_SLE)
1930 // We can't fold (ugt x, C) | (sgt x, C2).
1931 if (!PredicatesFoldable(LHSCC, RHSCC))
1934 // Ensure that the larger constant is on the RHS.
1936 if (CmpInst::isSigned(LHSCC) ||
1937 (ICmpInst::isEquality(LHSCC) &&
1938 CmpInst::isSigned(RHSCC)))
1939 ShouldSwap = LHSCst->getValue().sgt(RHSCst->getValue());
1941 ShouldSwap = LHSCst->getValue().ugt(RHSCst->getValue());
1944 std::swap(LHS, RHS);
1945 std::swap(LHSCst, RHSCst);
1946 std::swap(LHSCC, RHSCC);
1949 // At this point, we know we have two icmp instructions
1950 // comparing a value against two constants and or'ing the result
1951 // together. Because of the above check, we know that we only have
1952 // ICMP_EQ, ICMP_NE, ICMP_LT, and ICMP_GT here. We also know (from the
1953 // icmp folding check above), that the two constants are not
1955 assert(LHSCst != RHSCst && "Compares not folded above?");
1958 default: llvm_unreachable("Unknown integer condition code!");
1959 case ICmpInst::ICMP_EQ:
1961 default: llvm_unreachable("Unknown integer condition code!");
1962 case ICmpInst::ICMP_EQ:
1963 if (LHS->getOperand(0) == RHS->getOperand(0)) {
1964 // if LHSCst and RHSCst differ only by one bit:
1965 // (A == C1 || A == C2) -> (A | (C1 ^ C2)) == C2
1966 assert(LHSCst->getValue().ule(LHSCst->getValue()));
1968 APInt Xor = LHSCst->getValue() ^ RHSCst->getValue();
1969 if (Xor.isPowerOf2()) {
1970 Value *Cst = Builder->getInt(Xor);
1971 Value *Or = Builder->CreateOr(LHS->getOperand(0), Cst);
1972 return Builder->CreateICmp(ICmpInst::ICMP_EQ, Or, RHSCst);
1976 if (LHSCst == SubOne(RHSCst)) {
1977 // (X == 13 | X == 14) -> X-13 <u 2
1978 Constant *AddCST = ConstantExpr::getNeg(LHSCst);
1979 Value *Add = Builder->CreateAdd(Val, AddCST, Val->getName()+".off");
1980 AddCST = ConstantExpr::getSub(AddOne(RHSCst), LHSCst);
1981 return Builder->CreateICmpULT(Add, AddCST);
1984 break; // (X == 13 | X == 15) -> no change
1985 case ICmpInst::ICMP_UGT: // (X == 13 | X u> 14) -> no change
1986 case ICmpInst::ICMP_SGT: // (X == 13 | X s> 14) -> no change
1988 case ICmpInst::ICMP_NE: // (X == 13 | X != 15) -> X != 15
1989 case ICmpInst::ICMP_ULT: // (X == 13 | X u< 15) -> X u< 15
1990 case ICmpInst::ICMP_SLT: // (X == 13 | X s< 15) -> X s< 15
1994 case ICmpInst::ICMP_NE:
1996 default: llvm_unreachable("Unknown integer condition code!");
1997 case ICmpInst::ICMP_EQ: // (X != 13 | X == 15) -> X != 13
1998 case ICmpInst::ICMP_UGT: // (X != 13 | X u> 15) -> X != 13
1999 case ICmpInst::ICMP_SGT: // (X != 13 | X s> 15) -> X != 13
2001 case ICmpInst::ICMP_NE: // (X != 13 | X != 15) -> true
2002 case ICmpInst::ICMP_ULT: // (X != 13 | X u< 15) -> true
2003 case ICmpInst::ICMP_SLT: // (X != 13 | X s< 15) -> true
2004 return Builder->getTrue();
2006 case ICmpInst::ICMP_ULT:
2008 default: llvm_unreachable("Unknown integer condition code!");
2009 case ICmpInst::ICMP_EQ: // (X u< 13 | X == 14) -> no change
2011 case ICmpInst::ICMP_UGT: // (X u< 13 | X u> 15) -> (X-13) u> 2
2012 // If RHSCst is [us]MAXINT, it is always false. Not handling
2013 // this can cause overflow.
2014 if (RHSCst->isMaxValue(false))
2016 return InsertRangeTest(Val, LHSCst, AddOne(RHSCst), false, false);
2017 case ICmpInst::ICMP_SGT: // (X u< 13 | X s> 15) -> no change
2019 case ICmpInst::ICMP_NE: // (X u< 13 | X != 15) -> X != 15
2020 case ICmpInst::ICMP_ULT: // (X u< 13 | X u< 15) -> X u< 15
2022 case ICmpInst::ICMP_SLT: // (X u< 13 | X s< 15) -> no change
2026 case ICmpInst::ICMP_SLT:
2028 default: llvm_unreachable("Unknown integer condition code!");
2029 case ICmpInst::ICMP_EQ: // (X s< 13 | X == 14) -> no change
2031 case ICmpInst::ICMP_SGT: // (X s< 13 | X s> 15) -> (X-13) s> 2
2032 // If RHSCst is [us]MAXINT, it is always false. Not handling
2033 // this can cause overflow.
2034 if (RHSCst->isMaxValue(true))
2036 return InsertRangeTest(Val, LHSCst, AddOne(RHSCst), true, false);
2037 case ICmpInst::ICMP_UGT: // (X s< 13 | X u> 15) -> no change
2039 case ICmpInst::ICMP_NE: // (X s< 13 | X != 15) -> X != 15
2040 case ICmpInst::ICMP_SLT: // (X s< 13 | X s< 15) -> X s< 15
2042 case ICmpInst::ICMP_ULT: // (X s< 13 | X u< 15) -> no change
2046 case ICmpInst::ICMP_UGT:
2048 default: llvm_unreachable("Unknown integer condition code!");
2049 case ICmpInst::ICMP_EQ: // (X u> 13 | X == 15) -> X u> 13
2050 case ICmpInst::ICMP_UGT: // (X u> 13 | X u> 15) -> X u> 13
2052 case ICmpInst::ICMP_SGT: // (X u> 13 | X s> 15) -> no change
2054 case ICmpInst::ICMP_NE: // (X u> 13 | X != 15) -> true
2055 case ICmpInst::ICMP_ULT: // (X u> 13 | X u< 15) -> true
2056 return Builder->getTrue();
2057 case ICmpInst::ICMP_SLT: // (X u> 13 | X s< 15) -> no change
2061 case ICmpInst::ICMP_SGT:
2063 default: llvm_unreachable("Unknown integer condition code!");
2064 case ICmpInst::ICMP_EQ: // (X s> 13 | X == 15) -> X > 13
2065 case ICmpInst::ICMP_SGT: // (X s> 13 | X s> 15) -> X > 13
2067 case ICmpInst::ICMP_UGT: // (X s> 13 | X u> 15) -> no change
2069 case ICmpInst::ICMP_NE: // (X s> 13 | X != 15) -> true
2070 case ICmpInst::ICMP_SLT: // (X s> 13 | X s< 15) -> true
2071 return Builder->getTrue();
2072 case ICmpInst::ICMP_ULT: // (X s> 13 | X u< 15) -> no change
2080 /// Optimize (fcmp)|(fcmp). NOTE: Unlike the rest of instcombine, this returns
2081 /// a Value which should already be inserted into the function.
2082 Value *InstCombiner::FoldOrOfFCmps(FCmpInst *LHS, FCmpInst *RHS) {
2083 if (LHS->getPredicate() == FCmpInst::FCMP_UNO &&
2084 RHS->getPredicate() == FCmpInst::FCMP_UNO &&
2085 LHS->getOperand(0)->getType() == RHS->getOperand(0)->getType()) {
2086 if (ConstantFP *LHSC = dyn_cast<ConstantFP>(LHS->getOperand(1)))
2087 if (ConstantFP *RHSC = dyn_cast<ConstantFP>(RHS->getOperand(1))) {
2088 // If either of the constants are nans, then the whole thing returns
2090 if (LHSC->getValueAPF().isNaN() || RHSC->getValueAPF().isNaN())
2091 return Builder->getTrue();
2093 // Otherwise, no need to compare the two constants, compare the
2095 return Builder->CreateFCmpUNO(LHS->getOperand(0), RHS->getOperand(0));
2098 // Handle vector zeros. This occurs because the canonical form of
2099 // "fcmp uno x,x" is "fcmp uno x, 0".
2100 if (isa<ConstantAggregateZero>(LHS->getOperand(1)) &&
2101 isa<ConstantAggregateZero>(RHS->getOperand(1)))
2102 return Builder->CreateFCmpUNO(LHS->getOperand(0), RHS->getOperand(0));
2107 Value *Op0LHS = LHS->getOperand(0), *Op0RHS = LHS->getOperand(1);
2108 Value *Op1LHS = RHS->getOperand(0), *Op1RHS = RHS->getOperand(1);
2109 FCmpInst::Predicate Op0CC = LHS->getPredicate(), Op1CC = RHS->getPredicate();
2111 if (Op0LHS == Op1RHS && Op0RHS == Op1LHS) {
2112 // Swap RHS operands to match LHS.
2113 Op1CC = FCmpInst::getSwappedPredicate(Op1CC);
2114 std::swap(Op1LHS, Op1RHS);
2116 if (Op0LHS == Op1LHS && Op0RHS == Op1RHS) {
2117 // Simplify (fcmp cc0 x, y) | (fcmp cc1 x, y).
2119 return Builder->CreateFCmp((FCmpInst::Predicate)Op0CC, Op0LHS, Op0RHS);
2120 if (Op0CC == FCmpInst::FCMP_TRUE || Op1CC == FCmpInst::FCMP_TRUE)
2121 return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 1);
2122 if (Op0CC == FCmpInst::FCMP_FALSE)
2124 if (Op1CC == FCmpInst::FCMP_FALSE)
2128 unsigned Op0Pred = getFCmpCode(Op0CC, Op0Ordered);
2129 unsigned Op1Pred = getFCmpCode(Op1CC, Op1Ordered);
2130 if (Op0Ordered == Op1Ordered) {
2131 // If both are ordered or unordered, return a new fcmp with
2132 // or'ed predicates.
2133 return getFCmpValue(Op0Ordered, Op0Pred|Op1Pred, Op0LHS, Op0RHS, Builder);
2139 /// This helper function folds:
2141 /// ((A | B) & C1) | (B & C2)
2147 /// when the XOR of the two constants is "all ones" (-1).
2148 Instruction *InstCombiner::FoldOrWithConstants(BinaryOperator &I, Value *Op,
2149 Value *A, Value *B, Value *C) {
2150 ConstantInt *CI1 = dyn_cast<ConstantInt>(C);
2151 if (!CI1) return nullptr;
2153 Value *V1 = nullptr;
2154 ConstantInt *CI2 = nullptr;
2155 if (!match(Op, m_And(m_Value(V1), m_ConstantInt(CI2)))) return nullptr;
2157 APInt Xor = CI1->getValue() ^ CI2->getValue();
2158 if (!Xor.isAllOnesValue()) return nullptr;
2160 if (V1 == A || V1 == B) {
2161 Value *NewOp = Builder->CreateAnd((V1 == A) ? B : A, CI1);
2162 return BinaryOperator::CreateOr(NewOp, V1);
2168 /// \brief This helper function folds:
2170 /// ((A | B) & C1) ^ (B & C2)
2176 /// when the XOR of the two constants is "all ones" (-1).
2177 Instruction *InstCombiner::FoldXorWithConstants(BinaryOperator &I, Value *Op,
2178 Value *A, Value *B, Value *C) {
2179 ConstantInt *CI1 = dyn_cast<ConstantInt>(C);
2183 Value *V1 = nullptr;
2184 ConstantInt *CI2 = nullptr;
2185 if (!match(Op, m_And(m_Value(V1), m_ConstantInt(CI2))))
2188 APInt Xor = CI1->getValue() ^ CI2->getValue();
2189 if (!Xor.isAllOnesValue())
2192 if (V1 == A || V1 == B) {
2193 Value *NewOp = Builder->CreateAnd(V1 == A ? B : A, CI1);
2194 return BinaryOperator::CreateXor(NewOp, V1);
2200 Instruction *InstCombiner::visitOr(BinaryOperator &I) {
2201 bool Changed = SimplifyAssociativeOrCommutative(I);
2202 Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
2204 if (Value *V = SimplifyVectorOp(I))
2205 return ReplaceInstUsesWith(I, V);
2207 if (Value *V = SimplifyOrInst(Op0, Op1, DL, TLI, DT, AC))
2208 return ReplaceInstUsesWith(I, V);
2210 // (A&B)|(A&C) -> A&(B|C) etc
2211 if (Value *V = SimplifyUsingDistributiveLaws(I))
2212 return ReplaceInstUsesWith(I, V);
2214 // See if we can simplify any instructions used by the instruction whose sole
2215 // purpose is to compute bits we don't care about.
2216 if (SimplifyDemandedInstructionBits(I))
2219 if (Value *V = SimplifyBSwap(I))
2220 return ReplaceInstUsesWith(I, V);
2222 if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
2223 ConstantInt *C1 = nullptr; Value *X = nullptr;
2224 // (X & C1) | C2 --> (X | C2) & (C1|C2)
2225 // iff (C1 & C2) == 0.
2226 if (match(Op0, m_And(m_Value(X), m_ConstantInt(C1))) &&
2227 (RHS->getValue() & C1->getValue()) != 0 &&
2229 Value *Or = Builder->CreateOr(X, RHS);
2231 return BinaryOperator::CreateAnd(Or,
2232 Builder->getInt(RHS->getValue() | C1->getValue()));
2235 // (X ^ C1) | C2 --> (X | C2) ^ (C1&~C2)
2236 if (match(Op0, m_Xor(m_Value(X), m_ConstantInt(C1))) &&
2238 Value *Or = Builder->CreateOr(X, RHS);
2240 return BinaryOperator::CreateXor(Or,
2241 Builder->getInt(C1->getValue() & ~RHS->getValue()));
2244 // Try to fold constant and into select arguments.
2245 if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
2246 if (Instruction *R = FoldOpIntoSelect(I, SI))
2249 if (isa<PHINode>(Op0))
2250 if (Instruction *NV = FoldOpIntoPhi(I))
2254 Value *A = nullptr, *B = nullptr;
2255 ConstantInt *C1 = nullptr, *C2 = nullptr;
2257 // (A | B) | C and A | (B | C) -> bswap if possible.
2258 bool OrOfOrs = match(Op0, m_Or(m_Value(), m_Value())) ||
2259 match(Op1, m_Or(m_Value(), m_Value()));
2260 // (A >> B) | (C << D) and (A << B) | (B >> C) -> bswap if possible.
2261 bool OrOfShifts = match(Op0, m_LogicalShift(m_Value(), m_Value())) &&
2262 match(Op1, m_LogicalShift(m_Value(), m_Value()));
2263 // (A & B) | (C & D) -> bswap if possible.
2264 bool OrOfAnds = match(Op0, m_And(m_Value(), m_Value())) &&
2265 match(Op1, m_And(m_Value(), m_Value()));
2267 if (OrOfOrs || OrOfShifts || OrOfAnds)
2268 if (Instruction *BSwap = MatchBSwap(I))
2271 // (X^C)|Y -> (X|Y)^C iff Y&C == 0
2272 if (Op0->hasOneUse() &&
2273 match(Op0, m_Xor(m_Value(A), m_ConstantInt(C1))) &&
2274 MaskedValueIsZero(Op1, C1->getValue(), 0, &I)) {
2275 Value *NOr = Builder->CreateOr(A, Op1);
2277 return BinaryOperator::CreateXor(NOr, C1);
2280 // Y|(X^C) -> (X|Y)^C iff Y&C == 0
2281 if (Op1->hasOneUse() &&
2282 match(Op1, m_Xor(m_Value(A), m_ConstantInt(C1))) &&
2283 MaskedValueIsZero(Op0, C1->getValue(), 0, &I)) {
2284 Value *NOr = Builder->CreateOr(A, Op0);
2286 return BinaryOperator::CreateXor(NOr, C1);
2289 // ((~A & B) | A) -> (A | B)
2290 if (match(Op0, m_And(m_Not(m_Value(A)), m_Value(B))) &&
2291 match(Op1, m_Specific(A)))
2292 return BinaryOperator::CreateOr(A, B);
2294 // ((A & B) | ~A) -> (~A | B)
2295 if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
2296 match(Op1, m_Not(m_Specific(A))))
2297 return BinaryOperator::CreateOr(Builder->CreateNot(A), B);
2299 // (A & (~B)) | (A ^ B) -> (A ^ B)
2300 if (match(Op0, m_And(m_Value(A), m_Not(m_Value(B)))) &&
2301 match(Op1, m_Xor(m_Specific(A), m_Specific(B))))
2302 return BinaryOperator::CreateXor(A, B);
2304 // (A ^ B) | ( A & (~B)) -> (A ^ B)
2305 if (match(Op0, m_Xor(m_Value(A), m_Value(B))) &&
2306 match(Op1, m_And(m_Specific(A), m_Not(m_Specific(B)))))
2307 return BinaryOperator::CreateXor(A, B);
2310 Value *C = nullptr, *D = nullptr;
2311 if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
2312 match(Op1, m_And(m_Value(B), m_Value(D)))) {
2313 Value *V1 = nullptr, *V2 = nullptr;
2314 C1 = dyn_cast<ConstantInt>(C);
2315 C2 = dyn_cast<ConstantInt>(D);
2316 if (C1 && C2) { // (A & C1)|(B & C2)
2317 if ((C1->getValue() & C2->getValue()) == 0) {
2318 // ((V | N) & C1) | (V & C2) --> (V|N) & (C1|C2)
2319 // iff (C1&C2) == 0 and (N&~C1) == 0
2320 if (match(A, m_Or(m_Value(V1), m_Value(V2))) &&
2322 MaskedValueIsZero(V2, ~C1->getValue(), 0, &I)) || // (V|N)
2324 MaskedValueIsZero(V1, ~C1->getValue(), 0, &I)))) // (N|V)
2325 return BinaryOperator::CreateAnd(A,
2326 Builder->getInt(C1->getValue()|C2->getValue()));
2327 // Or commutes, try both ways.
2328 if (match(B, m_Or(m_Value(V1), m_Value(V2))) &&
2330 MaskedValueIsZero(V2, ~C2->getValue(), 0, &I)) || // (V|N)
2332 MaskedValueIsZero(V1, ~C2->getValue(), 0, &I)))) // (N|V)
2333 return BinaryOperator::CreateAnd(B,
2334 Builder->getInt(C1->getValue()|C2->getValue()));
2336 // ((V|C3)&C1) | ((V|C4)&C2) --> (V|C3|C4)&(C1|C2)
2337 // iff (C1&C2) == 0 and (C3&~C1) == 0 and (C4&~C2) == 0.
2338 ConstantInt *C3 = nullptr, *C4 = nullptr;
2339 if (match(A, m_Or(m_Value(V1), m_ConstantInt(C3))) &&
2340 (C3->getValue() & ~C1->getValue()) == 0 &&
2341 match(B, m_Or(m_Specific(V1), m_ConstantInt(C4))) &&
2342 (C4->getValue() & ~C2->getValue()) == 0) {
2343 V2 = Builder->CreateOr(V1, ConstantExpr::getOr(C3, C4), "bitfield");
2344 return BinaryOperator::CreateAnd(V2,
2345 Builder->getInt(C1->getValue()|C2->getValue()));
2350 // (A & (C0?-1:0)) | (B & ~(C0?-1:0)) -> C0 ? A : B, and commuted variants.
2351 // Don't do this for vector select idioms, the code generator doesn't handle
2353 if (!I.getType()->isVectorTy()) {
2354 if (Instruction *Match = MatchSelectFromAndOr(A, B, C, D))
2356 if (Instruction *Match = MatchSelectFromAndOr(B, A, D, C))
2358 if (Instruction *Match = MatchSelectFromAndOr(C, B, A, D))
2360 if (Instruction *Match = MatchSelectFromAndOr(D, A, B, C))
2364 // ((A&~B)|(~A&B)) -> A^B
2365 if ((match(C, m_Not(m_Specific(D))) &&
2366 match(B, m_Not(m_Specific(A)))))
2367 return BinaryOperator::CreateXor(A, D);
2368 // ((~B&A)|(~A&B)) -> A^B
2369 if ((match(A, m_Not(m_Specific(D))) &&
2370 match(B, m_Not(m_Specific(C)))))
2371 return BinaryOperator::CreateXor(C, D);
2372 // ((A&~B)|(B&~A)) -> A^B
2373 if ((match(C, m_Not(m_Specific(B))) &&
2374 match(D, m_Not(m_Specific(A)))))
2375 return BinaryOperator::CreateXor(A, B);
2376 // ((~B&A)|(B&~A)) -> A^B
2377 if ((match(A, m_Not(m_Specific(B))) &&
2378 match(D, m_Not(m_Specific(C)))))
2379 return BinaryOperator::CreateXor(C, B);
2381 // ((A|B)&1)|(B&-2) -> (A&1) | B
2382 if (match(A, m_Or(m_Value(V1), m_Specific(B))) ||
2383 match(A, m_Or(m_Specific(B), m_Value(V1)))) {
2384 Instruction *Ret = FoldOrWithConstants(I, Op1, V1, B, C);
2385 if (Ret) return Ret;
2387 // (B&-2)|((A|B)&1) -> (A&1) | B
2388 if (match(B, m_Or(m_Specific(A), m_Value(V1))) ||
2389 match(B, m_Or(m_Value(V1), m_Specific(A)))) {
2390 Instruction *Ret = FoldOrWithConstants(I, Op0, A, V1, D);
2391 if (Ret) return Ret;
2393 // ((A^B)&1)|(B&-2) -> (A&1) ^ B
2394 if (match(A, m_Xor(m_Value(V1), m_Specific(B))) ||
2395 match(A, m_Xor(m_Specific(B), m_Value(V1)))) {
2396 Instruction *Ret = FoldXorWithConstants(I, Op1, V1, B, C);
2397 if (Ret) return Ret;
2399 // (B&-2)|((A^B)&1) -> (A&1) ^ B
2400 if (match(B, m_Xor(m_Specific(A), m_Value(V1))) ||
2401 match(B, m_Xor(m_Value(V1), m_Specific(A)))) {
2402 Instruction *Ret = FoldXorWithConstants(I, Op0, A, V1, D);
2403 if (Ret) return Ret;
2407 // (A ^ B) | ((B ^ C) ^ A) -> (A ^ B) | C
2408 if (match(Op0, m_Xor(m_Value(A), m_Value(B))))
2409 if (match(Op1, m_Xor(m_Xor(m_Specific(B), m_Value(C)), m_Specific(A))))
2410 if (Op1->hasOneUse() || cast<BinaryOperator>(Op1)->hasOneUse())
2411 return BinaryOperator::CreateOr(Op0, C);
2413 // ((A ^ C) ^ B) | (B ^ A) -> (B ^ A) | C
2414 if (match(Op0, m_Xor(m_Xor(m_Value(A), m_Value(C)), m_Value(B))))
2415 if (match(Op1, m_Xor(m_Specific(B), m_Specific(A))))
2416 if (Op0->hasOneUse() || cast<BinaryOperator>(Op0)->hasOneUse())
2417 return BinaryOperator::CreateOr(Op1, C);
2419 // ((B | C) & A) | B -> B | (A & C)
2420 if (match(Op0, m_And(m_Or(m_Specific(Op1), m_Value(C)), m_Value(A))))
2421 return BinaryOperator::CreateOr(Op1, Builder->CreateAnd(A, C));
2423 if (Instruction *DeMorgan = matchDeMorgansLaws(I, Builder))
2426 // Canonicalize xor to the RHS.
2427 bool SwappedForXor = false;
2428 if (match(Op0, m_Xor(m_Value(), m_Value()))) {
2429 std::swap(Op0, Op1);
2430 SwappedForXor = true;
2433 // A | ( A ^ B) -> A | B
2434 // A | (~A ^ B) -> A | ~B
2435 // (A & B) | (A ^ B)
2436 if (match(Op1, m_Xor(m_Value(A), m_Value(B)))) {
2437 if (Op0 == A || Op0 == B)
2438 return BinaryOperator::CreateOr(A, B);
2440 if (match(Op0, m_And(m_Specific(A), m_Specific(B))) ||
2441 match(Op0, m_And(m_Specific(B), m_Specific(A))))
2442 return BinaryOperator::CreateOr(A, B);
2444 if (Op1->hasOneUse() && match(A, m_Not(m_Specific(Op0)))) {
2445 Value *Not = Builder->CreateNot(B, B->getName()+".not");
2446 return BinaryOperator::CreateOr(Not, Op0);
2448 if (Op1->hasOneUse() && match(B, m_Not(m_Specific(Op0)))) {
2449 Value *Not = Builder->CreateNot(A, A->getName()+".not");
2450 return BinaryOperator::CreateOr(Not, Op0);
2454 // A | ~(A | B) -> A | ~B
2455 // A | ~(A ^ B) -> A | ~B
2456 if (match(Op1, m_Not(m_Value(A))))
2457 if (BinaryOperator *B = dyn_cast<BinaryOperator>(A))
2458 if ((Op0 == B->getOperand(0) || Op0 == B->getOperand(1)) &&
2459 Op1->hasOneUse() && (B->getOpcode() == Instruction::Or ||
2460 B->getOpcode() == Instruction::Xor)) {
2461 Value *NotOp = Op0 == B->getOperand(0) ? B->getOperand(1) :
2463 Value *Not = Builder->CreateNot(NotOp, NotOp->getName()+".not");
2464 return BinaryOperator::CreateOr(Not, Op0);
2467 // (A & B) | ((~A) ^ B) -> (~A ^ B)
2468 if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
2469 match(Op1, m_Xor(m_Not(m_Specific(A)), m_Specific(B))))
2470 return BinaryOperator::CreateXor(Builder->CreateNot(A), B);
2472 // ((~A) ^ B) | (A & B) -> (~A ^ B)
2473 if (match(Op0, m_Xor(m_Not(m_Value(A)), m_Value(B))) &&
2474 match(Op1, m_And(m_Specific(A), m_Specific(B))))
2475 return BinaryOperator::CreateXor(Builder->CreateNot(A), B);
2478 std::swap(Op0, Op1);
2481 ICmpInst *LHS = dyn_cast<ICmpInst>(Op0);
2482 ICmpInst *RHS = dyn_cast<ICmpInst>(Op1);
2484 if (Value *Res = FoldOrOfICmps(LHS, RHS, &I))
2485 return ReplaceInstUsesWith(I, Res);
2487 // TODO: Make this recursive; it's a little tricky because an arbitrary
2488 // number of 'or' instructions might have to be created.
2490 if (LHS && match(Op1, m_OneUse(m_Or(m_Value(X), m_Value(Y))))) {
2491 if (auto *Cmp = dyn_cast<ICmpInst>(X))
2492 if (Value *Res = FoldOrOfICmps(LHS, Cmp, &I))
2493 return ReplaceInstUsesWith(I, Builder->CreateOr(Res, Y));
2494 if (auto *Cmp = dyn_cast<ICmpInst>(Y))
2495 if (Value *Res = FoldOrOfICmps(LHS, Cmp, &I))
2496 return ReplaceInstUsesWith(I, Builder->CreateOr(Res, X));
2498 if (RHS && match(Op0, m_OneUse(m_Or(m_Value(X), m_Value(Y))))) {
2499 if (auto *Cmp = dyn_cast<ICmpInst>(X))
2500 if (Value *Res = FoldOrOfICmps(Cmp, RHS, &I))
2501 return ReplaceInstUsesWith(I, Builder->CreateOr(Res, Y));
2502 if (auto *Cmp = dyn_cast<ICmpInst>(Y))
2503 if (Value *Res = FoldOrOfICmps(Cmp, RHS, &I))
2504 return ReplaceInstUsesWith(I, Builder->CreateOr(Res, X));
2508 // (fcmp uno x, c) | (fcmp uno y, c) -> (fcmp uno x, y)
2509 if (FCmpInst *LHS = dyn_cast<FCmpInst>(I.getOperand(0)))
2510 if (FCmpInst *RHS = dyn_cast<FCmpInst>(I.getOperand(1)))
2511 if (Value *Res = FoldOrOfFCmps(LHS, RHS))
2512 return ReplaceInstUsesWith(I, Res);
2514 // fold (or (cast A), (cast B)) -> (cast (or A, B))
2515 if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
2516 CastInst *Op1C = dyn_cast<CastInst>(Op1);
2517 if (Op1C && Op0C->getOpcode() == Op1C->getOpcode()) {// same cast kind ?
2518 Type *SrcTy = Op0C->getOperand(0)->getType();
2519 if (SrcTy == Op1C->getOperand(0)->getType() &&
2520 SrcTy->isIntOrIntVectorTy()) {
2521 Value *Op0COp = Op0C->getOperand(0), *Op1COp = Op1C->getOperand(0);
2523 if ((!isa<ICmpInst>(Op0COp) || !isa<ICmpInst>(Op1COp)) &&
2524 // Only do this if the casts both really cause code to be
2526 ShouldOptimizeCast(Op0C->getOpcode(), Op0COp, I.getType()) &&
2527 ShouldOptimizeCast(Op1C->getOpcode(), Op1COp, I.getType())) {
2528 Value *NewOp = Builder->CreateOr(Op0COp, Op1COp, I.getName());
2529 return CastInst::Create(Op0C->getOpcode(), NewOp, I.getType());
2532 // If this is or(cast(icmp), cast(icmp)), try to fold this even if the
2533 // cast is otherwise not optimizable. This happens for vector sexts.
2534 if (ICmpInst *RHS = dyn_cast<ICmpInst>(Op1COp))
2535 if (ICmpInst *LHS = dyn_cast<ICmpInst>(Op0COp))
2536 if (Value *Res = FoldOrOfICmps(LHS, RHS, &I))
2537 return CastInst::Create(Op0C->getOpcode(), Res, I.getType());
2539 // If this is or(cast(fcmp), cast(fcmp)), try to fold this even if the
2540 // cast is otherwise not optimizable. This happens for vector sexts.
2541 if (FCmpInst *RHS = dyn_cast<FCmpInst>(Op1COp))
2542 if (FCmpInst *LHS = dyn_cast<FCmpInst>(Op0COp))
2543 if (Value *Res = FoldOrOfFCmps(LHS, RHS))
2544 return CastInst::Create(Op0C->getOpcode(), Res, I.getType());
2549 // or(sext(A), B) -> A ? -1 : B where A is an i1
2550 // or(A, sext(B)) -> B ? -1 : A where B is an i1
2551 if (match(Op0, m_SExt(m_Value(A))) && A->getType()->isIntegerTy(1))
2552 return SelectInst::Create(A, ConstantInt::getSigned(I.getType(), -1), Op1);
2553 if (match(Op1, m_SExt(m_Value(A))) && A->getType()->isIntegerTy(1))
2554 return SelectInst::Create(A, ConstantInt::getSigned(I.getType(), -1), Op0);
2556 // Note: If we've gotten to the point of visiting the outer OR, then the
2557 // inner one couldn't be simplified. If it was a constant, then it won't
2558 // be simplified by a later pass either, so we try swapping the inner/outer
2559 // ORs in the hopes that we'll be able to simplify it this way.
2560 // (X|C) | V --> (X|V) | C
2561 if (Op0->hasOneUse() && !isa<ConstantInt>(Op1) &&
2562 match(Op0, m_Or(m_Value(A), m_ConstantInt(C1)))) {
2563 Value *Inner = Builder->CreateOr(A, Op1);
2564 Inner->takeName(Op0);
2565 return BinaryOperator::CreateOr(Inner, C1);
2568 // Change (or (bool?A:B),(bool?C:D)) --> (bool?(or A,C):(or B,D))
2569 // Since this OR statement hasn't been optimized further yet, we hope
2570 // that this transformation will allow the new ORs to be optimized.
2572 Value *X = nullptr, *Y = nullptr;
2573 if (Op0->hasOneUse() && Op1->hasOneUse() &&
2574 match(Op0, m_Select(m_Value(X), m_Value(A), m_Value(B))) &&
2575 match(Op1, m_Select(m_Value(Y), m_Value(C), m_Value(D))) && X == Y) {
2576 Value *orTrue = Builder->CreateOr(A, C);
2577 Value *orFalse = Builder->CreateOr(B, D);
2578 return SelectInst::Create(X, orTrue, orFalse);
2582 return Changed ? &I : nullptr;
2585 Instruction *InstCombiner::visitXor(BinaryOperator &I) {
2586 bool Changed = SimplifyAssociativeOrCommutative(I);
2587 Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
2589 if (Value *V = SimplifyVectorOp(I))
2590 return ReplaceInstUsesWith(I, V);
2592 if (Value *V = SimplifyXorInst(Op0, Op1, DL, TLI, DT, AC))
2593 return ReplaceInstUsesWith(I, V);
2595 // (A&B)^(A&C) -> A&(B^C) etc
2596 if (Value *V = SimplifyUsingDistributiveLaws(I))
2597 return ReplaceInstUsesWith(I, V);
2599 // See if we can simplify any instructions used by the instruction whose sole
2600 // purpose is to compute bits we don't care about.
2601 if (SimplifyDemandedInstructionBits(I))
2604 if (Value *V = SimplifyBSwap(I))
2605 return ReplaceInstUsesWith(I, V);
2607 // Is this a ~ operation?
2608 if (Value *NotOp = dyn_castNotVal(&I)) {
2609 if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(NotOp)) {
2610 if (Op0I->getOpcode() == Instruction::And ||
2611 Op0I->getOpcode() == Instruction::Or) {
2612 // ~(~X & Y) --> (X | ~Y) - De Morgan's Law
2613 // ~(~X | Y) === (X & ~Y) - De Morgan's Law
2614 if (dyn_castNotVal(Op0I->getOperand(1)))
2615 Op0I->swapOperands();
2616 if (Value *Op0NotVal = dyn_castNotVal(Op0I->getOperand(0))) {
2618 Builder->CreateNot(Op0I->getOperand(1),
2619 Op0I->getOperand(1)->getName()+".not");
2620 if (Op0I->getOpcode() == Instruction::And)
2621 return BinaryOperator::CreateOr(Op0NotVal, NotY);
2622 return BinaryOperator::CreateAnd(Op0NotVal, NotY);
2625 // ~(X & Y) --> (~X | ~Y) - De Morgan's Law
2626 // ~(X | Y) === (~X & ~Y) - De Morgan's Law
2627 if (IsFreeToInvert(Op0I->getOperand(0),
2628 Op0I->getOperand(0)->hasOneUse()) &&
2629 IsFreeToInvert(Op0I->getOperand(1),
2630 Op0I->getOperand(1)->hasOneUse())) {
2632 Builder->CreateNot(Op0I->getOperand(0), "notlhs");
2634 Builder->CreateNot(Op0I->getOperand(1), "notrhs");
2635 if (Op0I->getOpcode() == Instruction::And)
2636 return BinaryOperator::CreateOr(NotX, NotY);
2637 return BinaryOperator::CreateAnd(NotX, NotY);
2640 } else if (Op0I->getOpcode() == Instruction::AShr) {
2641 // ~(~X >>s Y) --> (X >>s Y)
2642 if (Value *Op0NotVal = dyn_castNotVal(Op0I->getOperand(0)))
2643 return BinaryOperator::CreateAShr(Op0NotVal, Op0I->getOperand(1));
2648 if (Constant *RHS = dyn_cast<Constant>(Op1)) {
2649 if (RHS->isAllOnesValue() && Op0->hasOneUse())
2650 // xor (cmp A, B), true = not (cmp A, B) = !cmp A, B
2651 if (CmpInst *CI = dyn_cast<CmpInst>(Op0))
2652 return CmpInst::Create(CI->getOpcode(),
2653 CI->getInversePredicate(),
2654 CI->getOperand(0), CI->getOperand(1));
2657 if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
2658 // fold (xor(zext(cmp)), 1) and (xor(sext(cmp)), -1) to ext(!cmp).
2659 if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
2660 if (CmpInst *CI = dyn_cast<CmpInst>(Op0C->getOperand(0))) {
2661 if (CI->hasOneUse() && Op0C->hasOneUse()) {
2662 Instruction::CastOps Opcode = Op0C->getOpcode();
2663 if ((Opcode == Instruction::ZExt || Opcode == Instruction::SExt) &&
2664 (RHS == ConstantExpr::getCast(Opcode, Builder->getTrue(),
2665 Op0C->getDestTy()))) {
2666 CI->setPredicate(CI->getInversePredicate());
2667 return CastInst::Create(Opcode, CI, Op0C->getType());
2673 if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
2674 // ~(c-X) == X-c-1 == X+(-c-1)
2675 if (Op0I->getOpcode() == Instruction::Sub && RHS->isAllOnesValue())
2676 if (Constant *Op0I0C = dyn_cast<Constant>(Op0I->getOperand(0))) {
2677 Constant *NegOp0I0C = ConstantExpr::getNeg(Op0I0C);
2678 Constant *ConstantRHS = ConstantExpr::getSub(NegOp0I0C,
2679 ConstantInt::get(I.getType(), 1));
2680 return BinaryOperator::CreateAdd(Op0I->getOperand(1), ConstantRHS);
2683 if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) {
2684 if (Op0I->getOpcode() == Instruction::Add) {
2685 // ~(X-c) --> (-c-1)-X
2686 if (RHS->isAllOnesValue()) {
2687 Constant *NegOp0CI = ConstantExpr::getNeg(Op0CI);
2688 return BinaryOperator::CreateSub(
2689 ConstantExpr::getSub(NegOp0CI,
2690 ConstantInt::get(I.getType(), 1)),
2691 Op0I->getOperand(0));
2692 } else if (RHS->getValue().isSignBit()) {
2693 // (X + C) ^ signbit -> (X + C + signbit)
2694 Constant *C = Builder->getInt(RHS->getValue() + Op0CI->getValue());
2695 return BinaryOperator::CreateAdd(Op0I->getOperand(0), C);
2698 } else if (Op0I->getOpcode() == Instruction::Or) {
2699 // (X|C1)^C2 -> X^(C1|C2) iff X&~C1 == 0
2700 if (MaskedValueIsZero(Op0I->getOperand(0), Op0CI->getValue(),
2702 Constant *NewRHS = ConstantExpr::getOr(Op0CI, RHS);
2703 // Anything in both C1 and C2 is known to be zero, remove it from
2705 Constant *CommonBits = ConstantExpr::getAnd(Op0CI, RHS);
2706 NewRHS = ConstantExpr::getAnd(NewRHS,
2707 ConstantExpr::getNot(CommonBits));
2709 I.setOperand(0, Op0I->getOperand(0));
2710 I.setOperand(1, NewRHS);
2713 } else if (Op0I->getOpcode() == Instruction::LShr) {
2714 // ((X^C1) >> C2) ^ C3 -> (X>>C2) ^ ((C1>>C2)^C3)
2718 if (Op0I->hasOneUse() &&
2719 (E1 = dyn_cast<BinaryOperator>(Op0I->getOperand(0))) &&
2720 E1->getOpcode() == Instruction::Xor &&
2721 (C1 = dyn_cast<ConstantInt>(E1->getOperand(1)))) {
2722 // fold (C1 >> C2) ^ C3
2723 ConstantInt *C2 = Op0CI, *C3 = RHS;
2724 APInt FoldConst = C1->getValue().lshr(C2->getValue());
2725 FoldConst ^= C3->getValue();
2726 // Prepare the two operands.
2727 Value *Opnd0 = Builder->CreateLShr(E1->getOperand(0), C2);
2728 Opnd0->takeName(Op0I);
2729 cast<Instruction>(Opnd0)->setDebugLoc(I.getDebugLoc());
2730 Value *FoldVal = ConstantInt::get(Opnd0->getType(), FoldConst);
2732 return BinaryOperator::CreateXor(Opnd0, FoldVal);
2738 // Try to fold constant and into select arguments.
2739 if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
2740 if (Instruction *R = FoldOpIntoSelect(I, SI))
2742 if (isa<PHINode>(Op0))
2743 if (Instruction *NV = FoldOpIntoPhi(I))
2747 BinaryOperator *Op1I = dyn_cast<BinaryOperator>(Op1);
2750 if (match(Op1I, m_Or(m_Value(A), m_Value(B)))) {
2751 if (A == Op0) { // B^(B|A) == (A|B)^B
2752 Op1I->swapOperands();
2754 std::swap(Op0, Op1);
2755 } else if (B == Op0) { // B^(A|B) == (A|B)^B
2756 I.swapOperands(); // Simplified below.
2757 std::swap(Op0, Op1);
2759 } else if (match(Op1I, m_And(m_Value(A), m_Value(B))) &&
2761 if (A == Op0) { // A^(A&B) -> A^(B&A)
2762 Op1I->swapOperands();
2765 if (B == Op0) { // A^(B&A) -> (B&A)^A
2766 I.swapOperands(); // Simplified below.
2767 std::swap(Op0, Op1);
2772 BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0);
2775 if (match(Op0I, m_Or(m_Value(A), m_Value(B))) &&
2776 Op0I->hasOneUse()) {
2777 if (A == Op1) // (B|A)^B == (A|B)^B
2779 if (B == Op1) // (A|B)^B == A & ~B
2780 return BinaryOperator::CreateAnd(A, Builder->CreateNot(Op1));
2781 } else if (match(Op0I, m_And(m_Value(A), m_Value(B))) &&
2783 if (A == Op1) // (A&B)^A -> (B&A)^A
2785 if (B == Op1 && // (B&A)^A == ~B & A
2786 !isa<ConstantInt>(Op1)) { // Canonical form is (B&C)^C
2787 return BinaryOperator::CreateAnd(Builder->CreateNot(A), Op1);
2793 Value *A, *B, *C, *D;
2794 // (A & B)^(A | B) -> A ^ B
2795 if (match(Op0I, m_And(m_Value(A), m_Value(B))) &&
2796 match(Op1I, m_Or(m_Value(C), m_Value(D)))) {
2797 if ((A == C && B == D) || (A == D && B == C))
2798 return BinaryOperator::CreateXor(A, B);
2800 // (A | B)^(A & B) -> A ^ B
2801 if (match(Op0I, m_Or(m_Value(A), m_Value(B))) &&
2802 match(Op1I, m_And(m_Value(C), m_Value(D)))) {
2803 if ((A == C && B == D) || (A == D && B == C))
2804 return BinaryOperator::CreateXor(A, B);
2806 // (A | ~B) ^ (~A | B) -> A ^ B
2807 if (match(Op0I, m_Or(m_Value(A), m_Not(m_Value(B)))) &&
2808 match(Op1I, m_Or(m_Not(m_Specific(A)), m_Specific(B)))) {
2809 return BinaryOperator::CreateXor(A, B);
2811 // (~A | B) ^ (A | ~B) -> A ^ B
2812 if (match(Op0I, m_Or(m_Not(m_Value(A)), m_Value(B))) &&
2813 match(Op1I, m_Or(m_Specific(A), m_Not(m_Specific(B))))) {
2814 return BinaryOperator::CreateXor(A, B);
2816 // (A & ~B) ^ (~A & B) -> A ^ B
2817 if (match(Op0I, m_And(m_Value(A), m_Not(m_Value(B)))) &&
2818 match(Op1I, m_And(m_Not(m_Specific(A)), m_Specific(B)))) {
2819 return BinaryOperator::CreateXor(A, B);
2821 // (~A & B) ^ (A & ~B) -> A ^ B
2822 if (match(Op0I, m_And(m_Not(m_Value(A)), m_Value(B))) &&
2823 match(Op1I, m_And(m_Specific(A), m_Not(m_Specific(B))))) {
2824 return BinaryOperator::CreateXor(A, B);
2826 // (A ^ C)^(A | B) -> ((~A) & B) ^ C
2827 if (match(Op0I, m_Xor(m_Value(D), m_Value(C))) &&
2828 match(Op1I, m_Or(m_Value(A), m_Value(B)))) {
2830 return BinaryOperator::CreateXor(
2831 Builder->CreateAnd(Builder->CreateNot(A), B), C);
2833 return BinaryOperator::CreateXor(
2834 Builder->CreateAnd(Builder->CreateNot(B), A), C);
2836 // (A | B)^(A ^ C) -> ((~A) & B) ^ C
2837 if (match(Op0I, m_Or(m_Value(A), m_Value(B))) &&
2838 match(Op1I, m_Xor(m_Value(D), m_Value(C)))) {
2840 return BinaryOperator::CreateXor(
2841 Builder->CreateAnd(Builder->CreateNot(A), B), C);
2843 return BinaryOperator::CreateXor(
2844 Builder->CreateAnd(Builder->CreateNot(B), A), C);
2846 // (A & B) ^ (A ^ B) -> (A | B)
2847 if (match(Op0I, m_And(m_Value(A), m_Value(B))) &&
2848 match(Op1I, m_Xor(m_Specific(A), m_Specific(B))))
2849 return BinaryOperator::CreateOr(A, B);
2850 // (A ^ B) ^ (A & B) -> (A | B)
2851 if (match(Op0I, m_Xor(m_Value(A), m_Value(B))) &&
2852 match(Op1I, m_And(m_Specific(A), m_Specific(B))))
2853 return BinaryOperator::CreateOr(A, B);
2856 Value *A = nullptr, *B = nullptr;
2857 // (A & ~B) ^ (~A) -> ~(A & B)
2858 if (match(Op0, m_And(m_Value(A), m_Not(m_Value(B)))) &&
2859 match(Op1, m_Not(m_Specific(A))))
2860 return BinaryOperator::CreateNot(Builder->CreateAnd(A, B));
2862 // (icmp1 A, B) ^ (icmp2 A, B) --> (icmp3 A, B)
2863 if (ICmpInst *RHS = dyn_cast<ICmpInst>(I.getOperand(1)))
2864 if (ICmpInst *LHS = dyn_cast<ICmpInst>(I.getOperand(0)))
2865 if (PredicatesFoldable(LHS->getPredicate(), RHS->getPredicate())) {
2866 if (LHS->getOperand(0) == RHS->getOperand(1) &&
2867 LHS->getOperand(1) == RHS->getOperand(0))
2868 LHS->swapOperands();
2869 if (LHS->getOperand(0) == RHS->getOperand(0) &&
2870 LHS->getOperand(1) == RHS->getOperand(1)) {
2871 Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1);
2872 unsigned Code = getICmpCode(LHS) ^ getICmpCode(RHS);
2873 bool isSigned = LHS->isSigned() || RHS->isSigned();
2874 return ReplaceInstUsesWith(I,
2875 getNewICmpValue(isSigned, Code, Op0, Op1,
2880 // fold (xor (cast A), (cast B)) -> (cast (xor A, B))
2881 if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
2882 if (CastInst *Op1C = dyn_cast<CastInst>(Op1))
2883 if (Op0C->getOpcode() == Op1C->getOpcode()) { // same cast kind?
2884 Type *SrcTy = Op0C->getOperand(0)->getType();
2885 if (SrcTy == Op1C->getOperand(0)->getType() && SrcTy->isIntegerTy() &&
2886 // Only do this if the casts both really cause code to be generated.
2887 ShouldOptimizeCast(Op0C->getOpcode(), Op0C->getOperand(0),
2889 ShouldOptimizeCast(Op1C->getOpcode(), Op1C->getOperand(0),
2891 Value *NewOp = Builder->CreateXor(Op0C->getOperand(0),
2892 Op1C->getOperand(0), I.getName());
2893 return CastInst::Create(Op0C->getOpcode(), NewOp, I.getType());
2898 return Changed ? &I : nullptr;