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 "InstCombine.h"
15 #include "llvm/Intrinsics.h"
16 #include "llvm/Analysis/InstructionSimplify.h"
17 #include "llvm/Transforms/Utils/CmpInstAnalysis.h"
18 #include "llvm/Support/ConstantRange.h"
19 #include "llvm/Support/PatternMatch.h"
21 using namespace PatternMatch;
24 /// AddOne - Add one to a ConstantInt.
25 static Constant *AddOne(Constant *C) {
26 return ConstantExpr::getAdd(C, ConstantInt::get(C->getType(), 1));
28 /// SubOne - Subtract one from a ConstantInt.
29 static Constant *SubOne(ConstantInt *C) {
30 return ConstantInt::get(C->getContext(), C->getValue()-1);
33 /// isFreeToInvert - Return true if the specified value is free to invert (apply
34 /// ~ to). This happens in cases where the ~ can be eliminated.
35 static inline bool isFreeToInvert(Value *V) {
37 if (BinaryOperator::isNot(V))
40 // Constants can be considered to be not'ed values.
41 if (isa<ConstantInt>(V))
44 // Compares can be inverted if they have a single use.
45 if (CmpInst *CI = dyn_cast<CmpInst>(V))
46 return CI->hasOneUse();
51 static inline Value *dyn_castNotVal(Value *V) {
52 // If this is not(not(x)) don't return that this is a not: we want the two
53 // not's to be folded first.
54 if (BinaryOperator::isNot(V)) {
55 Value *Operand = BinaryOperator::getNotArgument(V);
56 if (!isFreeToInvert(Operand))
60 // Constants can be considered to be not'ed values...
61 if (ConstantInt *C = dyn_cast<ConstantInt>(V))
62 return ConstantInt::get(C->getType(), ~C->getValue());
66 /// getFCmpCode - Similar to getICmpCode but for FCmpInst. This encodes a fcmp
67 /// predicate into a three bit mask. It also returns whether it is an ordered
68 /// predicate by reference.
69 static unsigned getFCmpCode(FCmpInst::Predicate CC, bool &isOrdered) {
72 case FCmpInst::FCMP_ORD: isOrdered = true; return 0; // 000
73 case FCmpInst::FCMP_UNO: return 0; // 000
74 case FCmpInst::FCMP_OGT: isOrdered = true; return 1; // 001
75 case FCmpInst::FCMP_UGT: return 1; // 001
76 case FCmpInst::FCMP_OEQ: isOrdered = true; return 2; // 010
77 case FCmpInst::FCMP_UEQ: return 2; // 010
78 case FCmpInst::FCMP_OGE: isOrdered = true; return 3; // 011
79 case FCmpInst::FCMP_UGE: return 3; // 011
80 case FCmpInst::FCMP_OLT: isOrdered = true; return 4; // 100
81 case FCmpInst::FCMP_ULT: return 4; // 100
82 case FCmpInst::FCMP_ONE: isOrdered = true; return 5; // 101
83 case FCmpInst::FCMP_UNE: return 5; // 101
84 case FCmpInst::FCMP_OLE: isOrdered = true; return 6; // 110
85 case FCmpInst::FCMP_ULE: return 6; // 110
88 // Not expecting FCMP_FALSE and FCMP_TRUE;
89 llvm_unreachable("Unexpected FCmp predicate!");
93 /// getNewICmpValue - This is the complement of getICmpCode, which turns an
94 /// opcode and two operands into either a constant true or false, or a brand
95 /// new ICmp instruction. The sign is passed in to determine which kind
96 /// of predicate to use in the new icmp instruction.
97 static Value *getNewICmpValue(bool Sign, unsigned Code, Value *LHS, Value *RHS,
98 InstCombiner::BuilderTy *Builder) {
99 ICmpInst::Predicate NewPred;
100 if (Value *NewConstant = getICmpValue(Sign, Code, LHS, RHS, NewPred))
102 return Builder->CreateICmp(NewPred, LHS, RHS);
105 /// getFCmpValue - This is the complement of getFCmpCode, which turns an
106 /// opcode and two operands into either a FCmp instruction. isordered is passed
107 /// in to determine which kind of predicate to use in the new fcmp instruction.
108 static Value *getFCmpValue(bool isordered, unsigned code,
109 Value *LHS, Value *RHS,
110 InstCombiner::BuilderTy *Builder) {
111 CmpInst::Predicate Pred;
113 default: llvm_unreachable("Illegal FCmp code!");
114 case 0: Pred = isordered ? FCmpInst::FCMP_ORD : FCmpInst::FCMP_UNO; break;
115 case 1: Pred = isordered ? FCmpInst::FCMP_OGT : FCmpInst::FCMP_UGT; break;
116 case 2: Pred = isordered ? FCmpInst::FCMP_OEQ : FCmpInst::FCMP_UEQ; break;
117 case 3: Pred = isordered ? FCmpInst::FCMP_OGE : FCmpInst::FCMP_UGE; break;
118 case 4: Pred = isordered ? FCmpInst::FCMP_OLT : FCmpInst::FCMP_ULT; break;
119 case 5: Pred = isordered ? FCmpInst::FCMP_ONE : FCmpInst::FCMP_UNE; break;
120 case 6: Pred = isordered ? FCmpInst::FCMP_OLE : FCmpInst::FCMP_ULE; break;
122 if (!isordered) return ConstantInt::getTrue(LHS->getContext());
123 Pred = FCmpInst::FCMP_ORD; break;
125 return Builder->CreateFCmp(Pred, LHS, RHS);
128 // OptAndOp - This handles expressions of the form ((val OP C1) & C2). Where
129 // the Op parameter is 'OP', OpRHS is 'C1', and AndRHS is 'C2'. Op is
130 // guaranteed to be a binary operator.
131 Instruction *InstCombiner::OptAndOp(Instruction *Op,
134 BinaryOperator &TheAnd) {
135 Value *X = Op->getOperand(0);
136 Constant *Together = 0;
138 Together = ConstantExpr::getAnd(AndRHS, OpRHS);
140 switch (Op->getOpcode()) {
141 case Instruction::Xor:
142 if (Op->hasOneUse()) {
143 // (X ^ C1) & C2 --> (X & C2) ^ (C1&C2)
144 Value *And = Builder->CreateAnd(X, AndRHS);
146 return BinaryOperator::CreateXor(And, Together);
149 case Instruction::Or:
150 if (Op->hasOneUse()){
151 if (Together != OpRHS) {
152 // (X | C1) & C2 --> (X | (C1&C2)) & C2
153 Value *Or = Builder->CreateOr(X, Together);
155 return BinaryOperator::CreateAnd(Or, AndRHS);
158 ConstantInt *TogetherCI = dyn_cast<ConstantInt>(Together);
159 if (TogetherCI && !TogetherCI->isZero()){
160 // (X | C1) & C2 --> (X & (C2^(C1&C2))) | C1
161 // NOTE: This reduces the number of bits set in the & mask, which
162 // can expose opportunities for store narrowing.
163 Together = ConstantExpr::getXor(AndRHS, Together);
164 Value *And = Builder->CreateAnd(X, Together);
166 return BinaryOperator::CreateOr(And, OpRHS);
171 case Instruction::Add:
172 if (Op->hasOneUse()) {
173 // Adding a one to a single bit bit-field should be turned into an XOR
174 // of the bit. First thing to check is to see if this AND is with a
175 // single bit constant.
176 const APInt &AndRHSV = cast<ConstantInt>(AndRHS)->getValue();
178 // If there is only one bit set.
179 if (AndRHSV.isPowerOf2()) {
180 // Ok, at this point, we know that we are masking the result of the
181 // ADD down to exactly one bit. If the constant we are adding has
182 // no bits set below this bit, then we can eliminate the ADD.
183 const APInt& AddRHS = cast<ConstantInt>(OpRHS)->getValue();
185 // Check to see if any bits below the one bit set in AndRHSV are set.
186 if ((AddRHS & (AndRHSV-1)) == 0) {
187 // If not, the only thing that can effect the output of the AND is
188 // the bit specified by AndRHSV. If that bit is set, the effect of
189 // the XOR is to toggle the bit. If it is clear, then the ADD has
191 if ((AddRHS & AndRHSV) == 0) { // Bit is not set, noop
192 TheAnd.setOperand(0, X);
195 // Pull the XOR out of the AND.
196 Value *NewAnd = Builder->CreateAnd(X, AndRHS);
197 NewAnd->takeName(Op);
198 return BinaryOperator::CreateXor(NewAnd, AndRHS);
205 case Instruction::Shl: {
206 // We know that the AND will not produce any of the bits shifted in, so if
207 // the anded constant includes them, clear them now!
209 uint32_t BitWidth = AndRHS->getType()->getBitWidth();
210 uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth);
211 APInt ShlMask(APInt::getHighBitsSet(BitWidth, BitWidth-OpRHSVal));
212 ConstantInt *CI = ConstantInt::get(AndRHS->getContext(),
213 AndRHS->getValue() & ShlMask);
215 if (CI->getValue() == ShlMask)
216 // Masking out bits that the shift already masks.
217 return ReplaceInstUsesWith(TheAnd, Op); // No need for the and.
219 if (CI != AndRHS) { // Reducing bits set in and.
220 TheAnd.setOperand(1, CI);
225 case Instruction::LShr: {
226 // We know that the AND will not produce any of the bits shifted in, so if
227 // the anded constant includes them, clear them now! This only applies to
228 // unsigned shifts, because a signed shr may bring in set bits!
230 uint32_t BitWidth = AndRHS->getType()->getBitWidth();
231 uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth);
232 APInt ShrMask(APInt::getLowBitsSet(BitWidth, BitWidth - OpRHSVal));
233 ConstantInt *CI = ConstantInt::get(Op->getContext(),
234 AndRHS->getValue() & ShrMask);
236 if (CI->getValue() == ShrMask)
237 // Masking out bits that the shift already masks.
238 return ReplaceInstUsesWith(TheAnd, Op);
241 TheAnd.setOperand(1, CI); // Reduce bits set in and cst.
246 case Instruction::AShr:
248 // See if this is shifting in some sign extension, then masking it out
250 if (Op->hasOneUse()) {
251 uint32_t BitWidth = AndRHS->getType()->getBitWidth();
252 uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth);
253 APInt ShrMask(APInt::getLowBitsSet(BitWidth, BitWidth - OpRHSVal));
254 Constant *C = ConstantInt::get(Op->getContext(),
255 AndRHS->getValue() & ShrMask);
256 if (C == AndRHS) { // Masking out bits shifted in.
257 // (Val ashr C1) & C2 -> (Val lshr C1) & C2
258 // Make the argument unsigned.
259 Value *ShVal = Op->getOperand(0);
260 ShVal = Builder->CreateLShr(ShVal, OpRHS, Op->getName());
261 return BinaryOperator::CreateAnd(ShVal, AndRHS, TheAnd.getName());
270 /// InsertRangeTest - Emit a computation of: (V >= Lo && V < Hi) if Inside is
271 /// true, otherwise (V < Lo || V >= Hi). In practice, we emit the more efficient
272 /// (V-Lo) <u Hi-Lo. This method expects that Lo <= Hi. isSigned indicates
273 /// whether to treat the V, Lo and HI as signed or not. IB is the location to
274 /// insert new instructions.
275 Value *InstCombiner::InsertRangeTest(Value *V, Constant *Lo, Constant *Hi,
276 bool isSigned, bool Inside) {
277 assert(cast<ConstantInt>(ConstantExpr::getICmp((isSigned ?
278 ICmpInst::ICMP_SLE:ICmpInst::ICMP_ULE), Lo, Hi))->getZExtValue() &&
279 "Lo is not <= Hi in range emission code!");
282 if (Lo == Hi) // Trivially false.
283 return ConstantInt::getFalse(V->getContext());
285 // V >= Min && V < Hi --> V < Hi
286 if (cast<ConstantInt>(Lo)->isMinValue(isSigned)) {
287 ICmpInst::Predicate pred = (isSigned ?
288 ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT);
289 return Builder->CreateICmp(pred, V, Hi);
292 // Emit V-Lo <u Hi-Lo
293 Constant *NegLo = ConstantExpr::getNeg(Lo);
294 Value *Add = Builder->CreateAdd(V, NegLo, V->getName()+".off");
295 Constant *UpperBound = ConstantExpr::getAdd(NegLo, Hi);
296 return Builder->CreateICmpULT(Add, UpperBound);
299 if (Lo == Hi) // Trivially true.
300 return ConstantInt::getTrue(V->getContext());
302 // V < Min || V >= Hi -> V > Hi-1
303 Hi = SubOne(cast<ConstantInt>(Hi));
304 if (cast<ConstantInt>(Lo)->isMinValue(isSigned)) {
305 ICmpInst::Predicate pred = (isSigned ?
306 ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT);
307 return Builder->CreateICmp(pred, V, Hi);
310 // Emit V-Lo >u Hi-1-Lo
311 // Note that Hi has already had one subtracted from it, above.
312 ConstantInt *NegLo = cast<ConstantInt>(ConstantExpr::getNeg(Lo));
313 Value *Add = Builder->CreateAdd(V, NegLo, V->getName()+".off");
314 Constant *LowerBound = ConstantExpr::getAdd(NegLo, Hi);
315 return Builder->CreateICmpUGT(Add, LowerBound);
318 // isRunOfOnes - Returns true if Val consists of one contiguous run of 1s with
319 // any number of 0s on either side. The 1s are allowed to wrap from LSB to
320 // MSB, so 0x000FFF0, 0x0000FFFF, and 0xFF0000FF are all runs. 0x0F0F0000 is
321 // not, since all 1s are not contiguous.
322 static bool isRunOfOnes(ConstantInt *Val, uint32_t &MB, uint32_t &ME) {
323 const APInt& V = Val->getValue();
324 uint32_t BitWidth = Val->getType()->getBitWidth();
325 if (!APIntOps::isShiftedMask(BitWidth, V)) return false;
327 // look for the first zero bit after the run of ones
328 MB = BitWidth - ((V - 1) ^ V).countLeadingZeros();
329 // look for the first non-zero bit
330 ME = V.getActiveBits();
334 /// FoldLogicalPlusAnd - This is part of an expression (LHS +/- RHS) & Mask,
335 /// where isSub determines whether the operator is a sub. If we can fold one of
336 /// the following xforms:
338 /// ((A & N) +/- B) & Mask -> (A +/- B) & Mask if N&Mask == Mask
339 /// ((A | N) +/- B) & Mask -> (A +/- B) & Mask if N&Mask == 0
340 /// ((A ^ N) +/- B) & Mask -> (A +/- B) & Mask if N&Mask == 0
342 /// return (A +/- B).
344 Value *InstCombiner::FoldLogicalPlusAnd(Value *LHS, Value *RHS,
345 ConstantInt *Mask, bool isSub,
347 Instruction *LHSI = dyn_cast<Instruction>(LHS);
348 if (!LHSI || LHSI->getNumOperands() != 2 ||
349 !isa<ConstantInt>(LHSI->getOperand(1))) return 0;
351 ConstantInt *N = cast<ConstantInt>(LHSI->getOperand(1));
353 switch (LHSI->getOpcode()) {
355 case Instruction::And:
356 if (ConstantExpr::getAnd(N, Mask) == Mask) {
357 // If the AndRHS is a power of two minus one (0+1+), this is simple.
358 if ((Mask->getValue().countLeadingZeros() +
359 Mask->getValue().countPopulation()) ==
360 Mask->getValue().getBitWidth())
363 // Otherwise, if Mask is 0+1+0+, and if B is known to have the low 0+
364 // part, we don't need any explicit masks to take them out of A. If that
365 // is all N is, ignore it.
366 uint32_t MB = 0, ME = 0;
367 if (isRunOfOnes(Mask, MB, ME)) { // begin/end bit of run, inclusive
368 uint32_t BitWidth = cast<IntegerType>(RHS->getType())->getBitWidth();
369 APInt Mask(APInt::getLowBitsSet(BitWidth, MB-1));
370 if (MaskedValueIsZero(RHS, Mask))
375 case Instruction::Or:
376 case Instruction::Xor:
377 // If the AndRHS is a power of two minus one (0+1+), and N&Mask == 0
378 if ((Mask->getValue().countLeadingZeros() +
379 Mask->getValue().countPopulation()) == Mask->getValue().getBitWidth()
380 && ConstantExpr::getAnd(N, Mask)->isNullValue())
386 return Builder->CreateSub(LHSI->getOperand(0), RHS, "fold");
387 return Builder->CreateAdd(LHSI->getOperand(0), RHS, "fold");
390 /// enum for classifying (icmp eq (A & B), C) and (icmp ne (A & B), C)
391 /// One of A and B is considered the mask, the other the value. This is
392 /// described as the "AMask" or "BMask" part of the enum. If the enum
393 /// contains only "Mask", then both A and B can be considered masks.
394 /// If A is the mask, then it was proven, that (A & C) == C. This
395 /// is trivial if C == A, or C == 0. If both A and C are constants, this
396 /// proof is also easy.
397 /// For the following explanations we assume that A is the mask.
398 /// The part "AllOnes" declares, that the comparison is true only
399 /// if (A & B) == A, or all bits of A are set in B.
400 /// Example: (icmp eq (A & 3), 3) -> FoldMskICmp_AMask_AllOnes
401 /// The part "AllZeroes" declares, that the comparison is true only
402 /// if (A & B) == 0, or all bits of A are cleared in B.
403 /// Example: (icmp eq (A & 3), 0) -> FoldMskICmp_Mask_AllZeroes
404 /// The part "Mixed" declares, that (A & B) == C and C might or might not
405 /// contain any number of one bits and zero bits.
406 /// Example: (icmp eq (A & 3), 1) -> FoldMskICmp_AMask_Mixed
407 /// The Part "Not" means, that in above descriptions "==" should be replaced
409 /// Example: (icmp ne (A & 3), 3) -> FoldMskICmp_AMask_NotAllOnes
410 /// If the mask A contains a single bit, then the following is equivalent:
411 /// (icmp eq (A & B), A) equals (icmp ne (A & B), 0)
412 /// (icmp ne (A & B), A) equals (icmp eq (A & B), 0)
413 enum MaskedICmpType {
414 FoldMskICmp_AMask_AllOnes = 1,
415 FoldMskICmp_AMask_NotAllOnes = 2,
416 FoldMskICmp_BMask_AllOnes = 4,
417 FoldMskICmp_BMask_NotAllOnes = 8,
418 FoldMskICmp_Mask_AllZeroes = 16,
419 FoldMskICmp_Mask_NotAllZeroes = 32,
420 FoldMskICmp_AMask_Mixed = 64,
421 FoldMskICmp_AMask_NotMixed = 128,
422 FoldMskICmp_BMask_Mixed = 256,
423 FoldMskICmp_BMask_NotMixed = 512
426 /// return the set of pattern classes (from MaskedICmpType)
427 /// that (icmp SCC (A & B), C) satisfies
428 static unsigned getTypeOfMaskedICmp(Value* A, Value* B, Value* C,
429 ICmpInst::Predicate SCC)
431 ConstantInt *ACst = dyn_cast<ConstantInt>(A);
432 ConstantInt *BCst = dyn_cast<ConstantInt>(B);
433 ConstantInt *CCst = dyn_cast<ConstantInt>(C);
434 bool icmp_eq = (SCC == ICmpInst::ICMP_EQ);
435 bool icmp_abit = (ACst != 0 && !ACst->isZero() &&
436 ACst->getValue().isPowerOf2());
437 bool icmp_bbit = (BCst != 0 && !BCst->isZero() &&
438 BCst->getValue().isPowerOf2());
440 if (CCst != 0 && CCst->isZero()) {
441 // if C is zero, then both A and B qualify as mask
442 result |= (icmp_eq ? (FoldMskICmp_Mask_AllZeroes |
443 FoldMskICmp_Mask_AllZeroes |
444 FoldMskICmp_AMask_Mixed |
445 FoldMskICmp_BMask_Mixed)
446 : (FoldMskICmp_Mask_NotAllZeroes |
447 FoldMskICmp_Mask_NotAllZeroes |
448 FoldMskICmp_AMask_NotMixed |
449 FoldMskICmp_BMask_NotMixed));
451 result |= (icmp_eq ? (FoldMskICmp_AMask_NotAllOnes |
452 FoldMskICmp_AMask_NotMixed)
453 : (FoldMskICmp_AMask_AllOnes |
454 FoldMskICmp_AMask_Mixed));
456 result |= (icmp_eq ? (FoldMskICmp_BMask_NotAllOnes |
457 FoldMskICmp_BMask_NotMixed)
458 : (FoldMskICmp_BMask_AllOnes |
459 FoldMskICmp_BMask_Mixed));
463 result |= (icmp_eq ? (FoldMskICmp_AMask_AllOnes |
464 FoldMskICmp_AMask_Mixed)
465 : (FoldMskICmp_AMask_NotAllOnes |
466 FoldMskICmp_AMask_NotMixed));
468 result |= (icmp_eq ? (FoldMskICmp_Mask_NotAllZeroes |
469 FoldMskICmp_AMask_NotMixed)
470 : (FoldMskICmp_Mask_AllZeroes |
471 FoldMskICmp_AMask_Mixed));
473 else if (ACst != 0 && CCst != 0 &&
474 ConstantExpr::getAnd(ACst, CCst) == CCst) {
475 result |= (icmp_eq ? FoldMskICmp_AMask_Mixed
476 : FoldMskICmp_AMask_NotMixed);
480 result |= (icmp_eq ? (FoldMskICmp_BMask_AllOnes |
481 FoldMskICmp_BMask_Mixed)
482 : (FoldMskICmp_BMask_NotAllOnes |
483 FoldMskICmp_BMask_NotMixed));
485 result |= (icmp_eq ? (FoldMskICmp_Mask_NotAllZeroes |
486 FoldMskICmp_BMask_NotMixed)
487 : (FoldMskICmp_Mask_AllZeroes |
488 FoldMskICmp_BMask_Mixed));
490 else if (BCst != 0 && CCst != 0 &&
491 ConstantExpr::getAnd(BCst, CCst) == CCst) {
492 result |= (icmp_eq ? FoldMskICmp_BMask_Mixed
493 : FoldMskICmp_BMask_NotMixed);
498 /// decomposeBitTestICmp - Decompose an icmp into the form ((X & Y) pred Z)
499 /// if possible. The returned predicate is either == or !=. Returns false if
500 /// decomposition fails.
501 static bool decomposeBitTestICmp(const ICmpInst *I, ICmpInst::Predicate &Pred,
502 Value *&X, Value *&Y, Value *&Z) {
503 // X < 0 is equivalent to (X & SignBit) != 0.
504 if (I->getPredicate() == ICmpInst::ICMP_SLT)
505 if (ConstantInt *C = dyn_cast<ConstantInt>(I->getOperand(1)))
507 X = I->getOperand(0);
508 Y = ConstantInt::get(I->getContext(),
509 APInt::getSignBit(C->getBitWidth()));
510 Pred = ICmpInst::ICMP_NE;
515 // X > -1 is equivalent to (X & SignBit) == 0.
516 if (I->getPredicate() == ICmpInst::ICMP_SGT)
517 if (ConstantInt *C = dyn_cast<ConstantInt>(I->getOperand(1)))
518 if (C->isAllOnesValue()) {
519 X = I->getOperand(0);
520 Y = ConstantInt::get(I->getContext(),
521 APInt::getSignBit(C->getBitWidth()));
522 Pred = ICmpInst::ICMP_EQ;
523 Z = ConstantInt::getNullValue(C->getType());
530 /// foldLogOpOfMaskedICmpsHelper:
531 /// handle (icmp(A & B) ==/!= C) &/| (icmp(A & D) ==/!= E)
532 /// return the set of pattern classes (from MaskedICmpType)
533 /// that both LHS and RHS satisfy
534 static unsigned foldLogOpOfMaskedICmpsHelper(Value*& A,
535 Value*& B, Value*& C,
536 Value*& D, Value*& E,
537 ICmpInst *LHS, ICmpInst *RHS,
538 ICmpInst::Predicate &LHSCC,
539 ICmpInst::Predicate &RHSCC) {
540 if (LHS->getOperand(0)->getType() != RHS->getOperand(0)->getType()) return 0;
541 // vectors are not (yet?) supported
542 if (LHS->getOperand(0)->getType()->isVectorTy()) return 0;
544 // Here comes the tricky part:
545 // LHS might be of the form L11 & L12 == X, X == L21 & L22,
546 // and L11 & L12 == L21 & L22. The same goes for RHS.
547 // Now we must find those components L** and R**, that are equal, so
548 // that we can extract the parameters A, B, C, D, and E for the canonical
550 Value *L1 = LHS->getOperand(0);
551 Value *L2 = LHS->getOperand(1);
552 Value *L11,*L12,*L21,*L22;
553 // Check whether the icmp can be decomposed into a bit test.
554 if (decomposeBitTestICmp(LHS, LHSCC, L11, L12, L2)) {
557 // Look for ANDs in the LHS icmp.
558 if (match(L1, m_And(m_Value(L11), m_Value(L12)))) {
559 if (!match(L2, m_And(m_Value(L21), m_Value(L22))))
562 if (!match(L2, m_And(m_Value(L11), m_Value(L12))))
569 // Bail if LHS was a icmp that can't be decomposed into an equality.
570 if (!ICmpInst::isEquality(LHSCC))
573 Value *R1 = RHS->getOperand(0);
574 Value *R2 = RHS->getOperand(1);
577 if (decomposeBitTestICmp(RHS, RHSCC, R11, R12, R2)) {
578 if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
580 } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
585 E = R2; R1 = 0; ok = true;
586 } else if (match(R1, m_And(m_Value(R11), m_Value(R12)))) {
587 if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
588 A = R11; D = R12; E = R2; ok = true;
589 } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
590 A = R12; D = R11; E = R2; ok = true;
594 // Bail if RHS was a icmp that can't be decomposed into an equality.
595 if (!ICmpInst::isEquality(RHSCC))
598 // Look for ANDs in on the right side of the RHS icmp.
599 if (!ok && match(R2, m_And(m_Value(R11), m_Value(R12)))) {
600 if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
601 A = R11; D = R12; E = R1; ok = true;
602 } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
603 A = R12; D = R11; E = R1; ok = true;
624 unsigned left_type = getTypeOfMaskedICmp(A, B, C, LHSCC);
625 unsigned right_type = getTypeOfMaskedICmp(A, D, E, RHSCC);
626 return left_type & right_type;
628 /// foldLogOpOfMaskedICmps:
629 /// try to fold (icmp(A & B) ==/!= C) &/| (icmp(A & D) ==/!= E)
630 /// into a single (icmp(A & X) ==/!= Y)
631 static Value* foldLogOpOfMaskedICmps(ICmpInst *LHS, ICmpInst *RHS,
632 ICmpInst::Predicate NEWCC,
633 llvm::InstCombiner::BuilderTy* Builder) {
634 Value *A = 0, *B = 0, *C = 0, *D = 0, *E = 0;
635 ICmpInst::Predicate LHSCC = LHS->getPredicate(), RHSCC = RHS->getPredicate();
636 unsigned mask = foldLogOpOfMaskedICmpsHelper(A, B, C, D, E, LHS, RHS,
638 if (mask == 0) return 0;
639 assert(ICmpInst::isEquality(LHSCC) && ICmpInst::isEquality(RHSCC) &&
640 "foldLogOpOfMaskedICmpsHelper must return an equality predicate.");
642 if (NEWCC == ICmpInst::ICMP_NE)
643 mask >>= 1; // treat "Not"-states as normal states
645 if (mask & FoldMskICmp_Mask_AllZeroes) {
646 // (icmp eq (A & B), 0) & (icmp eq (A & D), 0)
647 // -> (icmp eq (A & (B|D)), 0)
648 Value* newOr = Builder->CreateOr(B, D);
649 Value* newAnd = Builder->CreateAnd(A, newOr);
650 // we can't use C as zero, because we might actually handle
651 // (icmp ne (A & B), B) & (icmp ne (A & D), D)
652 // with B and D, having a single bit set
653 Value* zero = Constant::getNullValue(A->getType());
654 return Builder->CreateICmp(NEWCC, newAnd, zero);
656 else if (mask & FoldMskICmp_BMask_AllOnes) {
657 // (icmp eq (A & B), B) & (icmp eq (A & D), D)
658 // -> (icmp eq (A & (B|D)), (B|D))
659 Value* newOr = Builder->CreateOr(B, D);
660 Value* newAnd = Builder->CreateAnd(A, newOr);
661 return Builder->CreateICmp(NEWCC, newAnd, newOr);
663 else if (mask & FoldMskICmp_AMask_AllOnes) {
664 // (icmp eq (A & B), A) & (icmp eq (A & D), A)
665 // -> (icmp eq (A & (B&D)), A)
666 Value* newAnd1 = Builder->CreateAnd(B, D);
667 Value* newAnd = Builder->CreateAnd(A, newAnd1);
668 return Builder->CreateICmp(NEWCC, newAnd, A);
670 else if (mask & FoldMskICmp_BMask_Mixed) {
671 // (icmp eq (A & B), C) & (icmp eq (A & D), E)
672 // We already know that B & C == C && D & E == E.
673 // If we can prove that (B & D) & (C ^ E) == 0, that is, the bits of
674 // C and E, which are shared by both the mask B and the mask D, don't
675 // contradict, then we can transform to
676 // -> (icmp eq (A & (B|D)), (C|E))
677 // Currently, we only handle the case of B, C, D, and E being constant.
678 ConstantInt *BCst = dyn_cast<ConstantInt>(B);
679 if (BCst == 0) return 0;
680 ConstantInt *DCst = dyn_cast<ConstantInt>(D);
681 if (DCst == 0) return 0;
682 // we can't simply use C and E, because we might actually handle
683 // (icmp ne (A & B), B) & (icmp eq (A & D), D)
684 // with B and D, having a single bit set
686 ConstantInt *CCst = dyn_cast<ConstantInt>(C);
687 if (CCst == 0) return 0;
689 CCst = dyn_cast<ConstantInt>( ConstantExpr::getXor(BCst, CCst) );
690 ConstantInt *ECst = dyn_cast<ConstantInt>(E);
691 if (ECst == 0) return 0;
693 ECst = dyn_cast<ConstantInt>( ConstantExpr::getXor(DCst, ECst) );
694 ConstantInt* MCst = dyn_cast<ConstantInt>(
695 ConstantExpr::getAnd(ConstantExpr::getAnd(BCst, DCst),
696 ConstantExpr::getXor(CCst, ECst)) );
697 // if there is a conflict we should actually return a false for the
701 Value *newOr1 = Builder->CreateOr(B, D);
702 Value *newOr2 = ConstantExpr::getOr(CCst, ECst);
703 Value *newAnd = Builder->CreateAnd(A, newOr1);
704 return Builder->CreateICmp(NEWCC, newAnd, newOr2);
709 /// FoldAndOfICmps - Fold (icmp)&(icmp) if possible.
710 Value *InstCombiner::FoldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
711 ICmpInst::Predicate LHSCC = LHS->getPredicate(), RHSCC = RHS->getPredicate();
713 // (icmp1 A, B) & (icmp2 A, B) --> (icmp3 A, B)
714 if (PredicatesFoldable(LHSCC, RHSCC)) {
715 if (LHS->getOperand(0) == RHS->getOperand(1) &&
716 LHS->getOperand(1) == RHS->getOperand(0))
718 if (LHS->getOperand(0) == RHS->getOperand(0) &&
719 LHS->getOperand(1) == RHS->getOperand(1)) {
720 Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1);
721 unsigned Code = getICmpCode(LHS) & getICmpCode(RHS);
722 bool isSigned = LHS->isSigned() || RHS->isSigned();
723 return getNewICmpValue(isSigned, Code, Op0, Op1, Builder);
727 // handle (roughly): (icmp eq (A & B), C) & (icmp eq (A & D), E)
728 if (Value *V = foldLogOpOfMaskedICmps(LHS, RHS, ICmpInst::ICMP_EQ, Builder))
731 // This only handles icmp of constants: (icmp1 A, C1) & (icmp2 B, C2).
732 Value *Val = LHS->getOperand(0), *Val2 = RHS->getOperand(0);
733 ConstantInt *LHSCst = dyn_cast<ConstantInt>(LHS->getOperand(1));
734 ConstantInt *RHSCst = dyn_cast<ConstantInt>(RHS->getOperand(1));
735 if (LHSCst == 0 || RHSCst == 0) return 0;
737 if (LHSCst == RHSCst && LHSCC == RHSCC) {
738 // (icmp ult A, C) & (icmp ult B, C) --> (icmp ult (A|B), C)
739 // where C is a power of 2
740 if (LHSCC == ICmpInst::ICMP_ULT &&
741 LHSCst->getValue().isPowerOf2()) {
742 Value *NewOr = Builder->CreateOr(Val, Val2);
743 return Builder->CreateICmp(LHSCC, NewOr, LHSCst);
746 // (icmp eq A, 0) & (icmp eq B, 0) --> (icmp eq (A|B), 0)
747 if (LHSCC == ICmpInst::ICMP_EQ && LHSCst->isZero()) {
748 Value *NewOr = Builder->CreateOr(Val, Val2);
749 return Builder->CreateICmp(LHSCC, NewOr, LHSCst);
753 // (trunc x) == C1 & (and x, CA) == C2 -> (and x, CA|CMAX) == C1|C2
754 // where CMAX is the all ones value for the truncated type,
755 // if the lower bits of C2 and CA are zero.
756 if (LHSCC == ICmpInst::ICMP_EQ && LHSCC == RHSCC &&
757 LHS->hasOneUse() && RHS->hasOneUse()) {
759 ConstantInt *AndCst, *SmallCst = 0, *BigCst = 0;
761 // (trunc x) == C1 & (and x, CA) == C2
762 if (match(Val2, m_Trunc(m_Value(V))) &&
763 match(Val, m_And(m_Specific(V), m_ConstantInt(AndCst)))) {
767 // (and x, CA) == C2 & (trunc x) == C1
768 else if (match(Val, m_Trunc(m_Value(V))) &&
769 match(Val2, m_And(m_Specific(V), m_ConstantInt(AndCst)))) {
774 if (SmallCst && BigCst) {
775 unsigned BigBitSize = BigCst->getType()->getBitWidth();
776 unsigned SmallBitSize = SmallCst->getType()->getBitWidth();
778 // Check that the low bits are zero.
779 APInt Low = APInt::getLowBitsSet(BigBitSize, SmallBitSize);
780 if ((Low & AndCst->getValue()) == 0 && (Low & BigCst->getValue()) == 0) {
781 Value *NewAnd = Builder->CreateAnd(V, Low | AndCst->getValue());
782 APInt N = SmallCst->getValue().zext(BigBitSize) | BigCst->getValue();
783 Value *NewVal = ConstantInt::get(AndCst->getType()->getContext(), N);
784 return Builder->CreateICmp(LHSCC, NewAnd, NewVal);
789 // From here on, we only handle:
790 // (icmp1 A, C1) & (icmp2 A, C2) --> something simpler.
791 if (Val != Val2) return 0;
793 // ICMP_[US][GL]E X, CST is folded to ICMP_[US][GL]T elsewhere.
794 if (LHSCC == ICmpInst::ICMP_UGE || LHSCC == ICmpInst::ICMP_ULE ||
795 RHSCC == ICmpInst::ICMP_UGE || RHSCC == ICmpInst::ICMP_ULE ||
796 LHSCC == ICmpInst::ICMP_SGE || LHSCC == ICmpInst::ICMP_SLE ||
797 RHSCC == ICmpInst::ICMP_SGE || RHSCC == ICmpInst::ICMP_SLE)
800 // Make a constant range that's the intersection of the two icmp ranges.
801 // If the intersection is empty, we know that the result is false.
802 ConstantRange LHSRange =
803 ConstantRange::makeICmpRegion(LHSCC, LHSCst->getValue());
804 ConstantRange RHSRange =
805 ConstantRange::makeICmpRegion(RHSCC, RHSCst->getValue());
807 if (LHSRange.intersectWith(RHSRange).isEmptySet())
808 return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
810 // We can't fold (ugt x, C) & (sgt x, C2).
811 if (!PredicatesFoldable(LHSCC, RHSCC))
814 // Ensure that the larger constant is on the RHS.
816 if (CmpInst::isSigned(LHSCC) ||
817 (ICmpInst::isEquality(LHSCC) &&
818 CmpInst::isSigned(RHSCC)))
819 ShouldSwap = LHSCst->getValue().sgt(RHSCst->getValue());
821 ShouldSwap = LHSCst->getValue().ugt(RHSCst->getValue());
825 std::swap(LHSCst, RHSCst);
826 std::swap(LHSCC, RHSCC);
829 // At this point, we know we have two icmp instructions
830 // comparing a value against two constants and and'ing the result
831 // together. Because of the above check, we know that we only have
832 // icmp eq, icmp ne, icmp [su]lt, and icmp [SU]gt here. We also know
833 // (from the icmp folding check above), that the two constants
834 // are not equal and that the larger constant is on the RHS
835 assert(LHSCst != RHSCst && "Compares not folded above?");
838 default: llvm_unreachable("Unknown integer condition code!");
839 case ICmpInst::ICMP_EQ:
841 default: llvm_unreachable("Unknown integer condition code!");
842 case ICmpInst::ICMP_NE: // (X == 13 & X != 15) -> X == 13
843 case ICmpInst::ICMP_ULT: // (X == 13 & X < 15) -> X == 13
844 case ICmpInst::ICMP_SLT: // (X == 13 & X < 15) -> X == 13
847 case ICmpInst::ICMP_NE:
849 default: llvm_unreachable("Unknown integer condition code!");
850 case ICmpInst::ICMP_ULT:
851 if (LHSCst == SubOne(RHSCst)) // (X != 13 & X u< 14) -> X < 13
852 return Builder->CreateICmpULT(Val, LHSCst);
853 break; // (X != 13 & X u< 15) -> no change
854 case ICmpInst::ICMP_SLT:
855 if (LHSCst == SubOne(RHSCst)) // (X != 13 & X s< 14) -> X < 13
856 return Builder->CreateICmpSLT(Val, LHSCst);
857 break; // (X != 13 & X s< 15) -> no change
858 case ICmpInst::ICMP_EQ: // (X != 13 & X == 15) -> X == 15
859 case ICmpInst::ICMP_UGT: // (X != 13 & X u> 15) -> X u> 15
860 case ICmpInst::ICMP_SGT: // (X != 13 & X s> 15) -> X s> 15
862 case ICmpInst::ICMP_NE:
863 if (LHSCst == SubOne(RHSCst)){// (X != 13 & X != 14) -> X-13 >u 1
864 Constant *AddCST = ConstantExpr::getNeg(LHSCst);
865 Value *Add = Builder->CreateAdd(Val, AddCST, Val->getName()+".off");
866 return Builder->CreateICmpUGT(Add, ConstantInt::get(Add->getType(), 1));
868 break; // (X != 13 & X != 15) -> no change
871 case ICmpInst::ICMP_ULT:
873 default: llvm_unreachable("Unknown integer condition code!");
874 case ICmpInst::ICMP_EQ: // (X u< 13 & X == 15) -> false
875 case ICmpInst::ICMP_UGT: // (X u< 13 & X u> 15) -> false
876 return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
877 case ICmpInst::ICMP_SGT: // (X u< 13 & X s> 15) -> no change
879 case ICmpInst::ICMP_NE: // (X u< 13 & X != 15) -> X u< 13
880 case ICmpInst::ICMP_ULT: // (X u< 13 & X u< 15) -> X u< 13
882 case ICmpInst::ICMP_SLT: // (X u< 13 & X s< 15) -> no change
886 case ICmpInst::ICMP_SLT:
888 default: llvm_unreachable("Unknown integer condition code!");
889 case ICmpInst::ICMP_UGT: // (X s< 13 & X u> 15) -> no change
891 case ICmpInst::ICMP_NE: // (X s< 13 & X != 15) -> X < 13
892 case ICmpInst::ICMP_SLT: // (X s< 13 & X s< 15) -> X < 13
894 case ICmpInst::ICMP_ULT: // (X s< 13 & X u< 15) -> no change
898 case ICmpInst::ICMP_UGT:
900 default: llvm_unreachable("Unknown integer condition code!");
901 case ICmpInst::ICMP_EQ: // (X u> 13 & X == 15) -> X == 15
902 case ICmpInst::ICMP_UGT: // (X u> 13 & X u> 15) -> X u> 15
904 case ICmpInst::ICMP_SGT: // (X u> 13 & X s> 15) -> no change
906 case ICmpInst::ICMP_NE:
907 if (RHSCst == AddOne(LHSCst)) // (X u> 13 & X != 14) -> X u> 14
908 return Builder->CreateICmp(LHSCC, Val, RHSCst);
909 break; // (X u> 13 & X != 15) -> no change
910 case ICmpInst::ICMP_ULT: // (X u> 13 & X u< 15) -> (X-14) <u 1
911 return InsertRangeTest(Val, AddOne(LHSCst), RHSCst, false, true);
912 case ICmpInst::ICMP_SLT: // (X u> 13 & X s< 15) -> no change
916 case ICmpInst::ICMP_SGT:
918 default: llvm_unreachable("Unknown integer condition code!");
919 case ICmpInst::ICMP_EQ: // (X s> 13 & X == 15) -> X == 15
920 case ICmpInst::ICMP_SGT: // (X s> 13 & X s> 15) -> X s> 15
922 case ICmpInst::ICMP_UGT: // (X s> 13 & X u> 15) -> no change
924 case ICmpInst::ICMP_NE:
925 if (RHSCst == AddOne(LHSCst)) // (X s> 13 & X != 14) -> X s> 14
926 return Builder->CreateICmp(LHSCC, Val, RHSCst);
927 break; // (X s> 13 & X != 15) -> no change
928 case ICmpInst::ICMP_SLT: // (X s> 13 & X s< 15) -> (X-14) s< 1
929 return InsertRangeTest(Val, AddOne(LHSCst), RHSCst, true, true);
930 case ICmpInst::ICMP_ULT: // (X s> 13 & X u< 15) -> no change
939 /// FoldAndOfFCmps - Optimize (fcmp)&(fcmp). NOTE: Unlike the rest of
940 /// instcombine, this returns a Value which should already be inserted into the
942 Value *InstCombiner::FoldAndOfFCmps(FCmpInst *LHS, FCmpInst *RHS) {
943 if (LHS->getPredicate() == FCmpInst::FCMP_ORD &&
944 RHS->getPredicate() == FCmpInst::FCMP_ORD) {
945 // (fcmp ord x, c) & (fcmp ord y, c) -> (fcmp ord x, y)
946 if (ConstantFP *LHSC = dyn_cast<ConstantFP>(LHS->getOperand(1)))
947 if (ConstantFP *RHSC = dyn_cast<ConstantFP>(RHS->getOperand(1))) {
948 // If either of the constants are nans, then the whole thing returns
950 if (LHSC->getValueAPF().isNaN() || RHSC->getValueAPF().isNaN())
951 return ConstantInt::getFalse(LHS->getContext());
952 return Builder->CreateFCmpORD(LHS->getOperand(0), RHS->getOperand(0));
955 // Handle vector zeros. This occurs because the canonical form of
956 // "fcmp ord x,x" is "fcmp ord x, 0".
957 if (isa<ConstantAggregateZero>(LHS->getOperand(1)) &&
958 isa<ConstantAggregateZero>(RHS->getOperand(1)))
959 return Builder->CreateFCmpORD(LHS->getOperand(0), RHS->getOperand(0));
963 Value *Op0LHS = LHS->getOperand(0), *Op0RHS = LHS->getOperand(1);
964 Value *Op1LHS = RHS->getOperand(0), *Op1RHS = RHS->getOperand(1);
965 FCmpInst::Predicate Op0CC = LHS->getPredicate(), Op1CC = RHS->getPredicate();
968 if (Op0LHS == Op1RHS && Op0RHS == Op1LHS) {
969 // Swap RHS operands to match LHS.
970 Op1CC = FCmpInst::getSwappedPredicate(Op1CC);
971 std::swap(Op1LHS, Op1RHS);
974 if (Op0LHS == Op1LHS && Op0RHS == Op1RHS) {
975 // Simplify (fcmp cc0 x, y) & (fcmp cc1 x, y).
977 return Builder->CreateFCmp((FCmpInst::Predicate)Op0CC, Op0LHS, Op0RHS);
978 if (Op0CC == FCmpInst::FCMP_FALSE || Op1CC == FCmpInst::FCMP_FALSE)
979 return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
980 if (Op0CC == FCmpInst::FCMP_TRUE)
982 if (Op1CC == FCmpInst::FCMP_TRUE)
987 unsigned Op0Pred = getFCmpCode(Op0CC, Op0Ordered);
988 unsigned Op1Pred = getFCmpCode(Op1CC, Op1Ordered);
989 // uno && ord -> false
990 if (Op0Pred == 0 && Op1Pred == 0 && Op0Ordered != Op1Ordered)
991 return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
994 std::swap(Op0Pred, Op1Pred);
995 std::swap(Op0Ordered, Op1Ordered);
998 // uno && ueq -> uno && (uno || eq) -> uno
999 // ord && olt -> ord && (ord && lt) -> olt
1000 if (!Op0Ordered && (Op0Ordered == Op1Ordered))
1002 if (Op0Ordered && (Op0Ordered == Op1Ordered))
1005 // uno && oeq -> uno && (ord && eq) -> false
1007 return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
1008 // ord && ueq -> ord && (uno || eq) -> oeq
1009 return getFCmpValue(true, Op1Pred, Op0LHS, Op0RHS, Builder);
1017 Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
1018 bool Changed = SimplifyAssociativeOrCommutative(I);
1019 Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
1021 if (Value *V = SimplifyAndInst(Op0, Op1, TD))
1022 return ReplaceInstUsesWith(I, V);
1024 // (A|B)&(A|C) -> A|(B&C) etc
1025 if (Value *V = SimplifyUsingDistributiveLaws(I))
1026 return ReplaceInstUsesWith(I, V);
1028 // See if we can simplify any instructions used by the instruction whose sole
1029 // purpose is to compute bits we don't care about.
1030 if (SimplifyDemandedInstructionBits(I))
1033 if (ConstantInt *AndRHS = dyn_cast<ConstantInt>(Op1)) {
1034 const APInt &AndRHSMask = AndRHS->getValue();
1036 // Optimize a variety of ((val OP C1) & C2) combinations...
1037 if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
1038 Value *Op0LHS = Op0I->getOperand(0);
1039 Value *Op0RHS = Op0I->getOperand(1);
1040 switch (Op0I->getOpcode()) {
1042 case Instruction::Xor:
1043 case Instruction::Or: {
1044 // If the mask is only needed on one incoming arm, push it up.
1045 if (!Op0I->hasOneUse()) break;
1047 APInt NotAndRHS(~AndRHSMask);
1048 if (MaskedValueIsZero(Op0LHS, NotAndRHS)) {
1049 // Not masking anything out for the LHS, move to RHS.
1050 Value *NewRHS = Builder->CreateAnd(Op0RHS, AndRHS,
1051 Op0RHS->getName()+".masked");
1052 return BinaryOperator::Create(Op0I->getOpcode(), Op0LHS, NewRHS);
1054 if (!isa<Constant>(Op0RHS) &&
1055 MaskedValueIsZero(Op0RHS, NotAndRHS)) {
1056 // Not masking anything out for the RHS, move to LHS.
1057 Value *NewLHS = Builder->CreateAnd(Op0LHS, AndRHS,
1058 Op0LHS->getName()+".masked");
1059 return BinaryOperator::Create(Op0I->getOpcode(), NewLHS, Op0RHS);
1064 case Instruction::Add:
1065 // ((A & N) + B) & AndRHS -> (A + B) & AndRHS if N&AndRHS == AndRHS.
1066 // ((A | N) + B) & AndRHS -> (A + B) & AndRHS if N&AndRHS == 0
1067 // ((A ^ N) + B) & AndRHS -> (A + B) & AndRHS if N&AndRHS == 0
1068 if (Value *V = FoldLogicalPlusAnd(Op0LHS, Op0RHS, AndRHS, false, I))
1069 return BinaryOperator::CreateAnd(V, AndRHS);
1070 if (Value *V = FoldLogicalPlusAnd(Op0RHS, Op0LHS, AndRHS, false, I))
1071 return BinaryOperator::CreateAnd(V, AndRHS); // Add commutes
1074 case Instruction::Sub:
1075 // ((A & N) - B) & AndRHS -> (A - B) & AndRHS if N&AndRHS == AndRHS.
1076 // ((A | N) - B) & AndRHS -> (A - B) & AndRHS if N&AndRHS == 0
1077 // ((A ^ N) - B) & AndRHS -> (A - B) & AndRHS if N&AndRHS == 0
1078 if (Value *V = FoldLogicalPlusAnd(Op0LHS, Op0RHS, AndRHS, true, I))
1079 return BinaryOperator::CreateAnd(V, AndRHS);
1081 // (A - N) & AndRHS -> -N & AndRHS if A&AndRHS==0 and AndRHS
1082 // has 1's for all bits that the subtraction with A might affect.
1083 if (Op0I->hasOneUse() && !match(Op0LHS, m_Zero())) {
1084 uint32_t BitWidth = AndRHSMask.getBitWidth();
1085 uint32_t Zeros = AndRHSMask.countLeadingZeros();
1086 APInt Mask = APInt::getLowBitsSet(BitWidth, BitWidth - Zeros);
1088 if (MaskedValueIsZero(Op0LHS, Mask)) {
1089 Value *NewNeg = Builder->CreateNeg(Op0RHS);
1090 return BinaryOperator::CreateAnd(NewNeg, AndRHS);
1095 case Instruction::Shl:
1096 case Instruction::LShr:
1097 // (1 << x) & 1 --> zext(x == 0)
1098 // (1 >> x) & 1 --> zext(x == 0)
1099 if (AndRHSMask == 1 && Op0LHS == AndRHS) {
1101 Builder->CreateICmpEQ(Op0RHS, Constant::getNullValue(I.getType()));
1102 return new ZExtInst(NewICmp, I.getType());
1107 if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1)))
1108 if (Instruction *Res = OptAndOp(Op0I, Op0CI, AndRHS, I))
1112 // If this is an integer truncation, and if the source is an 'and' with
1113 // immediate, transform it. This frequently occurs for bitfield accesses.
1115 Value *X = 0; ConstantInt *YC = 0;
1116 if (match(Op0, m_Trunc(m_And(m_Value(X), m_ConstantInt(YC))))) {
1117 // Change: and (trunc (and X, YC) to T), C2
1118 // into : and (trunc X to T), trunc(YC) & C2
1119 // This will fold the two constants together, which may allow
1120 // other simplifications.
1121 Value *NewCast = Builder->CreateTrunc(X, I.getType(), "and.shrunk");
1122 Constant *C3 = ConstantExpr::getTrunc(YC, I.getType());
1123 C3 = ConstantExpr::getAnd(C3, AndRHS);
1124 return BinaryOperator::CreateAnd(NewCast, C3);
1128 // Try to fold constant and into select arguments.
1129 if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
1130 if (Instruction *R = FoldOpIntoSelect(I, SI))
1132 if (isa<PHINode>(Op0))
1133 if (Instruction *NV = FoldOpIntoPhi(I))
1138 // (~A & ~B) == (~(A | B)) - De Morgan's Law
1139 if (Value *Op0NotVal = dyn_castNotVal(Op0))
1140 if (Value *Op1NotVal = dyn_castNotVal(Op1))
1141 if (Op0->hasOneUse() && Op1->hasOneUse()) {
1142 Value *Or = Builder->CreateOr(Op0NotVal, Op1NotVal,
1143 I.getName()+".demorgan");
1144 return BinaryOperator::CreateNot(Or);
1148 Value *A = 0, *B = 0, *C = 0, *D = 0;
1149 // (A|B) & ~(A&B) -> A^B
1150 if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
1151 match(Op1, m_Not(m_And(m_Value(C), m_Value(D)))) &&
1152 ((A == C && B == D) || (A == D && B == C)))
1153 return BinaryOperator::CreateXor(A, B);
1155 // ~(A&B) & (A|B) -> A^B
1156 if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
1157 match(Op0, m_Not(m_And(m_Value(C), m_Value(D)))) &&
1158 ((A == C && B == D) || (A == D && B == C)))
1159 return BinaryOperator::CreateXor(A, B);
1161 // A&(A^B) => A & ~B
1163 Value *tmpOp0 = Op0;
1164 Value *tmpOp1 = Op1;
1165 if (Op0->hasOneUse() &&
1166 match(Op0, m_Xor(m_Value(A), m_Value(B)))) {
1167 if (A == Op1 || B == Op1 ) {
1174 if (tmpOp1->hasOneUse() &&
1175 match(tmpOp1, m_Xor(m_Value(A), m_Value(B)))) {
1179 // Notice that the patten (A&(~B)) is actually (A&(-1^B)), so if
1180 // A is originally -1 (or a vector of -1 and undefs), then we enter
1181 // an endless loop. By checking that A is non-constant we ensure that
1182 // we will never get to the loop.
1183 if (A == tmpOp0 && !isa<Constant>(A)) // A&(A^B) -> A & ~B
1184 return BinaryOperator::CreateAnd(A, Builder->CreateNot(B));
1188 // (A&((~A)|B)) -> A&B
1189 if (match(Op0, m_Or(m_Not(m_Specific(Op1)), m_Value(A))) ||
1190 match(Op0, m_Or(m_Value(A), m_Not(m_Specific(Op1)))))
1191 return BinaryOperator::CreateAnd(A, Op1);
1192 if (match(Op1, m_Or(m_Not(m_Specific(Op0)), m_Value(A))) ||
1193 match(Op1, m_Or(m_Value(A), m_Not(m_Specific(Op0)))))
1194 return BinaryOperator::CreateAnd(A, Op0);
1197 if (ICmpInst *RHS = dyn_cast<ICmpInst>(Op1))
1198 if (ICmpInst *LHS = dyn_cast<ICmpInst>(Op0))
1199 if (Value *Res = FoldAndOfICmps(LHS, RHS))
1200 return ReplaceInstUsesWith(I, Res);
1202 // If and'ing two fcmp, try combine them into one.
1203 if (FCmpInst *LHS = dyn_cast<FCmpInst>(I.getOperand(0)))
1204 if (FCmpInst *RHS = dyn_cast<FCmpInst>(I.getOperand(1)))
1205 if (Value *Res = FoldAndOfFCmps(LHS, RHS))
1206 return ReplaceInstUsesWith(I, Res);
1209 // fold (and (cast A), (cast B)) -> (cast (and A, B))
1210 if (CastInst *Op0C = dyn_cast<CastInst>(Op0))
1211 if (CastInst *Op1C = dyn_cast<CastInst>(Op1)) {
1212 Type *SrcTy = Op0C->getOperand(0)->getType();
1213 if (Op0C->getOpcode() == Op1C->getOpcode() && // same cast kind ?
1214 SrcTy == Op1C->getOperand(0)->getType() &&
1215 SrcTy->isIntOrIntVectorTy()) {
1216 Value *Op0COp = Op0C->getOperand(0), *Op1COp = Op1C->getOperand(0);
1218 // Only do this if the casts both really cause code to be generated.
1219 if (ShouldOptimizeCast(Op0C->getOpcode(), Op0COp, I.getType()) &&
1220 ShouldOptimizeCast(Op1C->getOpcode(), Op1COp, I.getType())) {
1221 Value *NewOp = Builder->CreateAnd(Op0COp, Op1COp, I.getName());
1222 return CastInst::Create(Op0C->getOpcode(), NewOp, I.getType());
1225 // If this is and(cast(icmp), cast(icmp)), try to fold this even if the
1226 // cast is otherwise not optimizable. This happens for vector sexts.
1227 if (ICmpInst *RHS = dyn_cast<ICmpInst>(Op1COp))
1228 if (ICmpInst *LHS = dyn_cast<ICmpInst>(Op0COp))
1229 if (Value *Res = FoldAndOfICmps(LHS, RHS))
1230 return CastInst::Create(Op0C->getOpcode(), Res, I.getType());
1232 // If this is and(cast(fcmp), cast(fcmp)), try to fold this even if the
1233 // cast is otherwise not optimizable. This happens for vector sexts.
1234 if (FCmpInst *RHS = dyn_cast<FCmpInst>(Op1COp))
1235 if (FCmpInst *LHS = dyn_cast<FCmpInst>(Op0COp))
1236 if (Value *Res = FoldAndOfFCmps(LHS, RHS))
1237 return CastInst::Create(Op0C->getOpcode(), Res, I.getType());
1241 // (X >> Z) & (Y >> Z) -> (X&Y) >> Z for all shifts.
1242 if (BinaryOperator *SI1 = dyn_cast<BinaryOperator>(Op1)) {
1243 if (BinaryOperator *SI0 = dyn_cast<BinaryOperator>(Op0))
1244 if (SI0->isShift() && SI0->getOpcode() == SI1->getOpcode() &&
1245 SI0->getOperand(1) == SI1->getOperand(1) &&
1246 (SI0->hasOneUse() || SI1->hasOneUse())) {
1248 Builder->CreateAnd(SI0->getOperand(0), SI1->getOperand(0),
1250 return BinaryOperator::Create(SI1->getOpcode(), NewOp,
1251 SI1->getOperand(1));
1255 return Changed ? &I : 0;
1258 /// CollectBSwapParts - Analyze the specified subexpression and see if it is
1259 /// capable of providing pieces of a bswap. The subexpression provides pieces
1260 /// of a bswap if it is proven that each of the non-zero bytes in the output of
1261 /// the expression came from the corresponding "byte swapped" byte in some other
1262 /// value. For example, if the current subexpression is "(shl i32 %X, 24)" then
1263 /// we know that the expression deposits the low byte of %X into the high byte
1264 /// of the bswap result and that all other bytes are zero. This expression is
1265 /// accepted, the high byte of ByteValues is set to X to indicate a correct
1268 /// This function returns true if the match was unsuccessful and false if so.
1269 /// On entry to the function the "OverallLeftShift" is a signed integer value
1270 /// indicating the number of bytes that the subexpression is later shifted. For
1271 /// example, if the expression is later right shifted by 16 bits, the
1272 /// OverallLeftShift value would be -2 on entry. This is used to specify which
1273 /// byte of ByteValues is actually being set.
1275 /// Similarly, ByteMask is a bitmask where a bit is clear if its corresponding
1276 /// byte is masked to zero by a user. For example, in (X & 255), X will be
1277 /// processed with a bytemask of 1. Because bytemask is 32-bits, this limits
1278 /// this function to working on up to 32-byte (256 bit) values. ByteMask is
1279 /// always in the local (OverallLeftShift) coordinate space.
1281 static bool CollectBSwapParts(Value *V, int OverallLeftShift, uint32_t ByteMask,
1282 SmallVector<Value*, 8> &ByteValues) {
1283 if (Instruction *I = dyn_cast<Instruction>(V)) {
1284 // If this is an or instruction, it may be an inner node of the bswap.
1285 if (I->getOpcode() == Instruction::Or) {
1286 return CollectBSwapParts(I->getOperand(0), OverallLeftShift, ByteMask,
1288 CollectBSwapParts(I->getOperand(1), OverallLeftShift, ByteMask,
1292 // If this is a logical shift by a constant multiple of 8, recurse with
1293 // OverallLeftShift and ByteMask adjusted.
1294 if (I->isLogicalShift() && isa<ConstantInt>(I->getOperand(1))) {
1296 cast<ConstantInt>(I->getOperand(1))->getLimitedValue(~0U);
1297 // Ensure the shift amount is defined and of a byte value.
1298 if ((ShAmt & 7) || (ShAmt > 8*ByteValues.size()))
1301 unsigned ByteShift = ShAmt >> 3;
1302 if (I->getOpcode() == Instruction::Shl) {
1303 // X << 2 -> collect(X, +2)
1304 OverallLeftShift += ByteShift;
1305 ByteMask >>= ByteShift;
1307 // X >>u 2 -> collect(X, -2)
1308 OverallLeftShift -= ByteShift;
1309 ByteMask <<= ByteShift;
1310 ByteMask &= (~0U >> (32-ByteValues.size()));
1313 if (OverallLeftShift >= (int)ByteValues.size()) return true;
1314 if (OverallLeftShift <= -(int)ByteValues.size()) return true;
1316 return CollectBSwapParts(I->getOperand(0), OverallLeftShift, ByteMask,
1320 // If this is a logical 'and' with a mask that clears bytes, clear the
1321 // corresponding bytes in ByteMask.
1322 if (I->getOpcode() == Instruction::And &&
1323 isa<ConstantInt>(I->getOperand(1))) {
1324 // Scan every byte of the and mask, seeing if the byte is either 0 or 255.
1325 unsigned NumBytes = ByteValues.size();
1326 APInt Byte(I->getType()->getPrimitiveSizeInBits(), 255);
1327 const APInt &AndMask = cast<ConstantInt>(I->getOperand(1))->getValue();
1329 for (unsigned i = 0; i != NumBytes; ++i, Byte <<= 8) {
1330 // If this byte is masked out by a later operation, we don't care what
1332 if ((ByteMask & (1 << i)) == 0)
1335 // If the AndMask is all zeros for this byte, clear the bit.
1336 APInt MaskB = AndMask & Byte;
1338 ByteMask &= ~(1U << i);
1342 // If the AndMask is not all ones for this byte, it's not a bytezap.
1346 // Otherwise, this byte is kept.
1349 return CollectBSwapParts(I->getOperand(0), OverallLeftShift, ByteMask,
1354 // Okay, we got to something that isn't a shift, 'or' or 'and'. This must be
1355 // the input value to the bswap. Some observations: 1) if more than one byte
1356 // is demanded from this input, then it could not be successfully assembled
1357 // into a byteswap. At least one of the two bytes would not be aligned with
1358 // their ultimate destination.
1359 if (!isPowerOf2_32(ByteMask)) return true;
1360 unsigned InputByteNo = CountTrailingZeros_32(ByteMask);
1362 // 2) The input and ultimate destinations must line up: if byte 3 of an i32
1363 // is demanded, it needs to go into byte 0 of the result. This means that the
1364 // byte needs to be shifted until it lands in the right byte bucket. The
1365 // shift amount depends on the position: if the byte is coming from the high
1366 // part of the value (e.g. byte 3) then it must be shifted right. If from the
1367 // low part, it must be shifted left.
1368 unsigned DestByteNo = InputByteNo + OverallLeftShift;
1369 if (ByteValues.size()-1-DestByteNo != InputByteNo)
1372 // If the destination byte value is already defined, the values are or'd
1373 // together, which isn't a bswap (unless it's an or of the same bits).
1374 if (ByteValues[DestByteNo] && ByteValues[DestByteNo] != V)
1376 ByteValues[DestByteNo] = V;
1380 /// MatchBSwap - Given an OR instruction, check to see if this is a bswap idiom.
1381 /// If so, insert the new bswap intrinsic and return it.
1382 Instruction *InstCombiner::MatchBSwap(BinaryOperator &I) {
1383 IntegerType *ITy = dyn_cast<IntegerType>(I.getType());
1384 if (!ITy || ITy->getBitWidth() % 16 ||
1385 // ByteMask only allows up to 32-byte values.
1386 ITy->getBitWidth() > 32*8)
1387 return 0; // Can only bswap pairs of bytes. Can't do vectors.
1389 /// ByteValues - For each byte of the result, we keep track of which value
1390 /// defines each byte.
1391 SmallVector<Value*, 8> ByteValues;
1392 ByteValues.resize(ITy->getBitWidth()/8);
1394 // Try to find all the pieces corresponding to the bswap.
1395 uint32_t ByteMask = ~0U >> (32-ByteValues.size());
1396 if (CollectBSwapParts(&I, 0, ByteMask, ByteValues))
1399 // Check to see if all of the bytes come from the same value.
1400 Value *V = ByteValues[0];
1401 if (V == 0) return 0; // Didn't find a byte? Must be zero.
1403 // Check to make sure that all of the bytes come from the same value.
1404 for (unsigned i = 1, e = ByteValues.size(); i != e; ++i)
1405 if (ByteValues[i] != V)
1407 Module *M = I.getParent()->getParent()->getParent();
1408 Function *F = Intrinsic::getDeclaration(M, Intrinsic::bswap, ITy);
1409 return CallInst::Create(F, V);
1412 /// MatchSelectFromAndOr - We have an expression of the form (A&C)|(B&D). Check
1413 /// If A is (cond?-1:0) and either B or D is ~(cond?-1,0) or (cond?0,-1), then
1414 /// we can simplify this expression to "cond ? C : D or B".
1415 static Instruction *MatchSelectFromAndOr(Value *A, Value *B,
1416 Value *C, Value *D) {
1417 // If A is not a select of -1/0, this cannot match.
1419 if (!match(A, m_SExt(m_Value(Cond))) ||
1420 !Cond->getType()->isIntegerTy(1))
1423 // ((cond?-1:0)&C) | (B&(cond?0:-1)) -> cond ? C : B.
1424 if (match(D, m_Not(m_SExt(m_Specific(Cond)))))
1425 return SelectInst::Create(Cond, C, B);
1426 if (match(D, m_SExt(m_Not(m_Specific(Cond)))))
1427 return SelectInst::Create(Cond, C, B);
1429 // ((cond?-1:0)&C) | ((cond?0:-1)&D) -> cond ? C : D.
1430 if (match(B, m_Not(m_SExt(m_Specific(Cond)))))
1431 return SelectInst::Create(Cond, C, D);
1432 if (match(B, m_SExt(m_Not(m_Specific(Cond)))))
1433 return SelectInst::Create(Cond, C, D);
1437 /// FoldOrOfICmps - Fold (icmp)|(icmp) if possible.
1438 Value *InstCombiner::FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
1439 ICmpInst::Predicate LHSCC = LHS->getPredicate(), RHSCC = RHS->getPredicate();
1441 // (icmp1 A, B) | (icmp2 A, B) --> (icmp3 A, B)
1442 if (PredicatesFoldable(LHSCC, RHSCC)) {
1443 if (LHS->getOperand(0) == RHS->getOperand(1) &&
1444 LHS->getOperand(1) == RHS->getOperand(0))
1445 LHS->swapOperands();
1446 if (LHS->getOperand(0) == RHS->getOperand(0) &&
1447 LHS->getOperand(1) == RHS->getOperand(1)) {
1448 Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1);
1449 unsigned Code = getICmpCode(LHS) | getICmpCode(RHS);
1450 bool isSigned = LHS->isSigned() || RHS->isSigned();
1451 return getNewICmpValue(isSigned, Code, Op0, Op1, Builder);
1455 // handle (roughly):
1456 // (icmp ne (A & B), C) | (icmp ne (A & D), E)
1457 if (Value *V = foldLogOpOfMaskedICmps(LHS, RHS, ICmpInst::ICMP_NE, Builder))
1460 // This only handles icmp of constants: (icmp1 A, C1) | (icmp2 B, C2).
1461 Value *Val = LHS->getOperand(0), *Val2 = RHS->getOperand(0);
1462 ConstantInt *LHSCst = dyn_cast<ConstantInt>(LHS->getOperand(1));
1463 ConstantInt *RHSCst = dyn_cast<ConstantInt>(RHS->getOperand(1));
1464 if (LHSCst == 0 || RHSCst == 0) return 0;
1466 if (LHSCst == RHSCst && LHSCC == RHSCC) {
1467 // (icmp ne A, 0) | (icmp ne B, 0) --> (icmp ne (A|B), 0)
1468 if (LHSCC == ICmpInst::ICMP_NE && LHSCst->isZero()) {
1469 Value *NewOr = Builder->CreateOr(Val, Val2);
1470 return Builder->CreateICmp(LHSCC, NewOr, LHSCst);
1474 // (icmp ult (X + CA), C1) | (icmp eq X, C2) -> (icmp ule (X + CA), C1)
1475 // if C2 + CA == C1.
1476 if (LHSCC == ICmpInst::ICMP_ULT && RHSCC == ICmpInst::ICMP_EQ) {
1477 ConstantInt *AddCst;
1478 if (match(Val, m_Add(m_Specific(Val2), m_ConstantInt(AddCst))))
1479 if (RHSCst->getValue() + AddCst->getValue() == LHSCst->getValue())
1480 return Builder->CreateICmpULE(Val, LHSCst);
1483 // From here on, we only handle:
1484 // (icmp1 A, C1) | (icmp2 A, C2) --> something simpler.
1485 if (Val != Val2) return 0;
1487 // ICMP_[US][GL]E X, CST is folded to ICMP_[US][GL]T elsewhere.
1488 if (LHSCC == ICmpInst::ICMP_UGE || LHSCC == ICmpInst::ICMP_ULE ||
1489 RHSCC == ICmpInst::ICMP_UGE || RHSCC == ICmpInst::ICMP_ULE ||
1490 LHSCC == ICmpInst::ICMP_SGE || LHSCC == ICmpInst::ICMP_SLE ||
1491 RHSCC == ICmpInst::ICMP_SGE || RHSCC == ICmpInst::ICMP_SLE)
1494 // We can't fold (ugt x, C) | (sgt x, C2).
1495 if (!PredicatesFoldable(LHSCC, RHSCC))
1498 // Ensure that the larger constant is on the RHS.
1500 if (CmpInst::isSigned(LHSCC) ||
1501 (ICmpInst::isEquality(LHSCC) &&
1502 CmpInst::isSigned(RHSCC)))
1503 ShouldSwap = LHSCst->getValue().sgt(RHSCst->getValue());
1505 ShouldSwap = LHSCst->getValue().ugt(RHSCst->getValue());
1508 std::swap(LHS, RHS);
1509 std::swap(LHSCst, RHSCst);
1510 std::swap(LHSCC, RHSCC);
1513 // At this point, we know we have two icmp instructions
1514 // comparing a value against two constants and or'ing the result
1515 // together. Because of the above check, we know that we only have
1516 // ICMP_EQ, ICMP_NE, ICMP_LT, and ICMP_GT here. We also know (from the
1517 // icmp folding check above), that the two constants are not
1519 assert(LHSCst != RHSCst && "Compares not folded above?");
1522 default: llvm_unreachable("Unknown integer condition code!");
1523 case ICmpInst::ICMP_EQ:
1525 default: llvm_unreachable("Unknown integer condition code!");
1526 case ICmpInst::ICMP_EQ:
1527 if (LHSCst == SubOne(RHSCst)) {
1528 // (X == 13 | X == 14) -> X-13 <u 2
1529 Constant *AddCST = ConstantExpr::getNeg(LHSCst);
1530 Value *Add = Builder->CreateAdd(Val, AddCST, Val->getName()+".off");
1531 AddCST = ConstantExpr::getSub(AddOne(RHSCst), LHSCst);
1532 return Builder->CreateICmpULT(Add, AddCST);
1534 break; // (X == 13 | X == 15) -> no change
1535 case ICmpInst::ICMP_UGT: // (X == 13 | X u> 14) -> no change
1536 case ICmpInst::ICMP_SGT: // (X == 13 | X s> 14) -> no change
1538 case ICmpInst::ICMP_NE: // (X == 13 | X != 15) -> X != 15
1539 case ICmpInst::ICMP_ULT: // (X == 13 | X u< 15) -> X u< 15
1540 case ICmpInst::ICMP_SLT: // (X == 13 | X s< 15) -> X s< 15
1544 case ICmpInst::ICMP_NE:
1546 default: llvm_unreachable("Unknown integer condition code!");
1547 case ICmpInst::ICMP_EQ: // (X != 13 | X == 15) -> X != 13
1548 case ICmpInst::ICMP_UGT: // (X != 13 | X u> 15) -> X != 13
1549 case ICmpInst::ICMP_SGT: // (X != 13 | X s> 15) -> X != 13
1551 case ICmpInst::ICMP_NE: // (X != 13 | X != 15) -> true
1552 case ICmpInst::ICMP_ULT: // (X != 13 | X u< 15) -> true
1553 case ICmpInst::ICMP_SLT: // (X != 13 | X s< 15) -> true
1554 return ConstantInt::getTrue(LHS->getContext());
1556 case ICmpInst::ICMP_ULT:
1558 default: llvm_unreachable("Unknown integer condition code!");
1559 case ICmpInst::ICMP_EQ: // (X u< 13 | X == 14) -> no change
1561 case ICmpInst::ICMP_UGT: // (X u< 13 | X u> 15) -> (X-13) u> 2
1562 // If RHSCst is [us]MAXINT, it is always false. Not handling
1563 // this can cause overflow.
1564 if (RHSCst->isMaxValue(false))
1566 return InsertRangeTest(Val, LHSCst, AddOne(RHSCst), false, false);
1567 case ICmpInst::ICMP_SGT: // (X u< 13 | X s> 15) -> no change
1569 case ICmpInst::ICMP_NE: // (X u< 13 | X != 15) -> X != 15
1570 case ICmpInst::ICMP_ULT: // (X u< 13 | X u< 15) -> X u< 15
1572 case ICmpInst::ICMP_SLT: // (X u< 13 | X s< 15) -> no change
1576 case ICmpInst::ICMP_SLT:
1578 default: llvm_unreachable("Unknown integer condition code!");
1579 case ICmpInst::ICMP_EQ: // (X s< 13 | X == 14) -> no change
1581 case ICmpInst::ICMP_SGT: // (X s< 13 | X s> 15) -> (X-13) s> 2
1582 // If RHSCst is [us]MAXINT, it is always false. Not handling
1583 // this can cause overflow.
1584 if (RHSCst->isMaxValue(true))
1586 return InsertRangeTest(Val, LHSCst, AddOne(RHSCst), true, false);
1587 case ICmpInst::ICMP_UGT: // (X s< 13 | X u> 15) -> no change
1589 case ICmpInst::ICMP_NE: // (X s< 13 | X != 15) -> X != 15
1590 case ICmpInst::ICMP_SLT: // (X s< 13 | X s< 15) -> X s< 15
1592 case ICmpInst::ICMP_ULT: // (X s< 13 | X u< 15) -> no change
1596 case ICmpInst::ICMP_UGT:
1598 default: llvm_unreachable("Unknown integer condition code!");
1599 case ICmpInst::ICMP_EQ: // (X u> 13 | X == 15) -> X u> 13
1600 case ICmpInst::ICMP_UGT: // (X u> 13 | X u> 15) -> X u> 13
1602 case ICmpInst::ICMP_SGT: // (X u> 13 | X s> 15) -> no change
1604 case ICmpInst::ICMP_NE: // (X u> 13 | X != 15) -> true
1605 case ICmpInst::ICMP_ULT: // (X u> 13 | X u< 15) -> true
1606 return ConstantInt::getTrue(LHS->getContext());
1607 case ICmpInst::ICMP_SLT: // (X u> 13 | X s< 15) -> no change
1611 case ICmpInst::ICMP_SGT:
1613 default: llvm_unreachable("Unknown integer condition code!");
1614 case ICmpInst::ICMP_EQ: // (X s> 13 | X == 15) -> X > 13
1615 case ICmpInst::ICMP_SGT: // (X s> 13 | X s> 15) -> X > 13
1617 case ICmpInst::ICMP_UGT: // (X s> 13 | X u> 15) -> no change
1619 case ICmpInst::ICMP_NE: // (X s> 13 | X != 15) -> true
1620 case ICmpInst::ICMP_SLT: // (X s> 13 | X s< 15) -> true
1621 return ConstantInt::getTrue(LHS->getContext());
1622 case ICmpInst::ICMP_ULT: // (X s> 13 | X u< 15) -> no change
1630 /// FoldOrOfFCmps - Optimize (fcmp)|(fcmp). NOTE: Unlike the rest of
1631 /// instcombine, this returns a Value which should already be inserted into the
1633 Value *InstCombiner::FoldOrOfFCmps(FCmpInst *LHS, FCmpInst *RHS) {
1634 if (LHS->getPredicate() == FCmpInst::FCMP_UNO &&
1635 RHS->getPredicate() == FCmpInst::FCMP_UNO &&
1636 LHS->getOperand(0)->getType() == RHS->getOperand(0)->getType()) {
1637 if (ConstantFP *LHSC = dyn_cast<ConstantFP>(LHS->getOperand(1)))
1638 if (ConstantFP *RHSC = dyn_cast<ConstantFP>(RHS->getOperand(1))) {
1639 // If either of the constants are nans, then the whole thing returns
1641 if (LHSC->getValueAPF().isNaN() || RHSC->getValueAPF().isNaN())
1642 return ConstantInt::getTrue(LHS->getContext());
1644 // Otherwise, no need to compare the two constants, compare the
1646 return Builder->CreateFCmpUNO(LHS->getOperand(0), RHS->getOperand(0));
1649 // Handle vector zeros. This occurs because the canonical form of
1650 // "fcmp uno x,x" is "fcmp uno x, 0".
1651 if (isa<ConstantAggregateZero>(LHS->getOperand(1)) &&
1652 isa<ConstantAggregateZero>(RHS->getOperand(1)))
1653 return Builder->CreateFCmpUNO(LHS->getOperand(0), RHS->getOperand(0));
1658 Value *Op0LHS = LHS->getOperand(0), *Op0RHS = LHS->getOperand(1);
1659 Value *Op1LHS = RHS->getOperand(0), *Op1RHS = RHS->getOperand(1);
1660 FCmpInst::Predicate Op0CC = LHS->getPredicate(), Op1CC = RHS->getPredicate();
1662 if (Op0LHS == Op1RHS && Op0RHS == Op1LHS) {
1663 // Swap RHS operands to match LHS.
1664 Op1CC = FCmpInst::getSwappedPredicate(Op1CC);
1665 std::swap(Op1LHS, Op1RHS);
1667 if (Op0LHS == Op1LHS && Op0RHS == Op1RHS) {
1668 // Simplify (fcmp cc0 x, y) | (fcmp cc1 x, y).
1670 return Builder->CreateFCmp((FCmpInst::Predicate)Op0CC, Op0LHS, Op0RHS);
1671 if (Op0CC == FCmpInst::FCMP_TRUE || Op1CC == FCmpInst::FCMP_TRUE)
1672 return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 1);
1673 if (Op0CC == FCmpInst::FCMP_FALSE)
1675 if (Op1CC == FCmpInst::FCMP_FALSE)
1679 unsigned Op0Pred = getFCmpCode(Op0CC, Op0Ordered);
1680 unsigned Op1Pred = getFCmpCode(Op1CC, Op1Ordered);
1681 if (Op0Ordered == Op1Ordered) {
1682 // If both are ordered or unordered, return a new fcmp with
1683 // or'ed predicates.
1684 return getFCmpValue(Op0Ordered, Op0Pred|Op1Pred, Op0LHS, Op0RHS, Builder);
1690 /// FoldOrWithConstants - This helper function folds:
1692 /// ((A | B) & C1) | (B & C2)
1698 /// when the XOR of the two constants is "all ones" (-1).
1699 Instruction *InstCombiner::FoldOrWithConstants(BinaryOperator &I, Value *Op,
1700 Value *A, Value *B, Value *C) {
1701 ConstantInt *CI1 = dyn_cast<ConstantInt>(C);
1705 ConstantInt *CI2 = 0;
1706 if (!match(Op, m_And(m_Value(V1), m_ConstantInt(CI2)))) return 0;
1708 APInt Xor = CI1->getValue() ^ CI2->getValue();
1709 if (!Xor.isAllOnesValue()) return 0;
1711 if (V1 == A || V1 == B) {
1712 Value *NewOp = Builder->CreateAnd((V1 == A) ? B : A, CI1);
1713 return BinaryOperator::CreateOr(NewOp, V1);
1719 Instruction *InstCombiner::visitOr(BinaryOperator &I) {
1720 bool Changed = SimplifyAssociativeOrCommutative(I);
1721 Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
1723 if (Value *V = SimplifyOrInst(Op0, Op1, TD))
1724 return ReplaceInstUsesWith(I, V);
1726 // (A&B)|(A&C) -> A&(B|C) etc
1727 if (Value *V = SimplifyUsingDistributiveLaws(I))
1728 return ReplaceInstUsesWith(I, V);
1730 // See if we can simplify any instructions used by the instruction whose sole
1731 // purpose is to compute bits we don't care about.
1732 if (SimplifyDemandedInstructionBits(I))
1735 if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
1736 ConstantInt *C1 = 0; Value *X = 0;
1737 // (X & C1) | C2 --> (X | C2) & (C1|C2)
1738 // if (C1 & C2) == 0.
1739 if (match(Op0, m_And(m_Value(X), m_ConstantInt(C1))) &&
1740 (RHS->getValue() & C1->getValue()) != 0 &&
1742 Value *Or = Builder->CreateOr(X, RHS);
1744 return BinaryOperator::CreateAnd(Or,
1745 ConstantInt::get(I.getContext(),
1746 RHS->getValue() | C1->getValue()));
1749 // (X ^ C1) | C2 --> (X | C2) ^ (C1&~C2)
1750 if (match(Op0, m_Xor(m_Value(X), m_ConstantInt(C1))) &&
1752 Value *Or = Builder->CreateOr(X, RHS);
1754 return BinaryOperator::CreateXor(Or,
1755 ConstantInt::get(I.getContext(),
1756 C1->getValue() & ~RHS->getValue()));
1759 // Try to fold constant and into select arguments.
1760 if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
1761 if (Instruction *R = FoldOpIntoSelect(I, SI))
1764 if (isa<PHINode>(Op0))
1765 if (Instruction *NV = FoldOpIntoPhi(I))
1769 Value *A = 0, *B = 0;
1770 ConstantInt *C1 = 0, *C2 = 0;
1772 // (A | B) | C and A | (B | C) -> bswap if possible.
1773 // (A >> B) | (C << D) and (A << B) | (B >> C) -> bswap if possible.
1774 if (match(Op0, m_Or(m_Value(), m_Value())) ||
1775 match(Op1, m_Or(m_Value(), m_Value())) ||
1776 (match(Op0, m_LogicalShift(m_Value(), m_Value())) &&
1777 match(Op1, m_LogicalShift(m_Value(), m_Value())))) {
1778 if (Instruction *BSwap = MatchBSwap(I))
1782 // (X^C)|Y -> (X|Y)^C if Y&C == 0
1783 if (Op0->hasOneUse() &&
1784 match(Op0, m_Xor(m_Value(A), m_ConstantInt(C1))) &&
1785 MaskedValueIsZero(Op1, C1->getValue())) {
1786 Value *NOr = Builder->CreateOr(A, Op1);
1788 return BinaryOperator::CreateXor(NOr, C1);
1791 // Y|(X^C) -> (X|Y)^C if Y&C == 0
1792 if (Op1->hasOneUse() &&
1793 match(Op1, m_Xor(m_Value(A), m_ConstantInt(C1))) &&
1794 MaskedValueIsZero(Op0, C1->getValue())) {
1795 Value *NOr = Builder->CreateOr(A, Op0);
1797 return BinaryOperator::CreateXor(NOr, C1);
1801 Value *C = 0, *D = 0;
1802 if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
1803 match(Op1, m_And(m_Value(B), m_Value(D)))) {
1804 Value *V1 = 0, *V2 = 0;
1805 C1 = dyn_cast<ConstantInt>(C);
1806 C2 = dyn_cast<ConstantInt>(D);
1807 if (C1 && C2) { // (A & C1)|(B & C2)
1808 // If we have: ((V + N) & C1) | (V & C2)
1809 // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
1810 // replace with V+N.
1811 if (C1->getValue() == ~C2->getValue()) {
1812 if ((C2->getValue() & (C2->getValue()+1)) == 0 && // C2 == 0+1+
1813 match(A, m_Add(m_Value(V1), m_Value(V2)))) {
1814 // Add commutes, try both ways.
1815 if (V1 == B && MaskedValueIsZero(V2, C2->getValue()))
1816 return ReplaceInstUsesWith(I, A);
1817 if (V2 == B && MaskedValueIsZero(V1, C2->getValue()))
1818 return ReplaceInstUsesWith(I, A);
1820 // Or commutes, try both ways.
1821 if ((C1->getValue() & (C1->getValue()+1)) == 0 &&
1822 match(B, m_Add(m_Value(V1), m_Value(V2)))) {
1823 // Add commutes, try both ways.
1824 if (V1 == A && MaskedValueIsZero(V2, C1->getValue()))
1825 return ReplaceInstUsesWith(I, B);
1826 if (V2 == A && MaskedValueIsZero(V1, C1->getValue()))
1827 return ReplaceInstUsesWith(I, B);
1831 if ((C1->getValue() & C2->getValue()) == 0) {
1832 // ((V | N) & C1) | (V & C2) --> (V|N) & (C1|C2)
1833 // if (C1&C2) == 0 and (N&~C1) == 0
1834 if (match(A, m_Or(m_Value(V1), m_Value(V2))) &&
1835 ((V1 == B && MaskedValueIsZero(V2, ~C1->getValue())) || // (V|N)
1836 (V2 == B && MaskedValueIsZero(V1, ~C1->getValue())))) // (N|V)
1837 return BinaryOperator::CreateAnd(A,
1838 ConstantInt::get(A->getContext(),
1839 C1->getValue()|C2->getValue()));
1840 // Or commutes, try both ways.
1841 if (match(B, m_Or(m_Value(V1), m_Value(V2))) &&
1842 ((V1 == A && MaskedValueIsZero(V2, ~C2->getValue())) || // (V|N)
1843 (V2 == A && MaskedValueIsZero(V1, ~C2->getValue())))) // (N|V)
1844 return BinaryOperator::CreateAnd(B,
1845 ConstantInt::get(B->getContext(),
1846 C1->getValue()|C2->getValue()));
1848 // ((V|C3)&C1) | ((V|C4)&C2) --> (V|C3|C4)&(C1|C2)
1849 // if (C1&C2) == 0 and (C3&~C1) == 0 and (C4&~C2) == 0.
1850 ConstantInt *C3 = 0, *C4 = 0;
1851 if (match(A, m_Or(m_Value(V1), m_ConstantInt(C3))) &&
1852 (C3->getValue() & ~C1->getValue()) == 0 &&
1853 match(B, m_Or(m_Specific(V1), m_ConstantInt(C4))) &&
1854 (C4->getValue() & ~C2->getValue()) == 0) {
1855 V2 = Builder->CreateOr(V1, ConstantExpr::getOr(C3, C4), "bitfield");
1856 return BinaryOperator::CreateAnd(V2,
1857 ConstantInt::get(B->getContext(),
1858 C1->getValue()|C2->getValue()));
1863 // (A & (C0?-1:0)) | (B & ~(C0?-1:0)) -> C0 ? A : B, and commuted variants.
1864 // Don't do this for vector select idioms, the code generator doesn't handle
1866 if (!I.getType()->isVectorTy()) {
1867 if (Instruction *Match = MatchSelectFromAndOr(A, B, C, D))
1869 if (Instruction *Match = MatchSelectFromAndOr(B, A, D, C))
1871 if (Instruction *Match = MatchSelectFromAndOr(C, B, A, D))
1873 if (Instruction *Match = MatchSelectFromAndOr(D, A, B, C))
1877 // ((A&~B)|(~A&B)) -> A^B
1878 if ((match(C, m_Not(m_Specific(D))) &&
1879 match(B, m_Not(m_Specific(A)))))
1880 return BinaryOperator::CreateXor(A, D);
1881 // ((~B&A)|(~A&B)) -> A^B
1882 if ((match(A, m_Not(m_Specific(D))) &&
1883 match(B, m_Not(m_Specific(C)))))
1884 return BinaryOperator::CreateXor(C, D);
1885 // ((A&~B)|(B&~A)) -> A^B
1886 if ((match(C, m_Not(m_Specific(B))) &&
1887 match(D, m_Not(m_Specific(A)))))
1888 return BinaryOperator::CreateXor(A, B);
1889 // ((~B&A)|(B&~A)) -> A^B
1890 if ((match(A, m_Not(m_Specific(B))) &&
1891 match(D, m_Not(m_Specific(C)))))
1892 return BinaryOperator::CreateXor(C, B);
1894 // ((A|B)&1)|(B&-2) -> (A&1) | B
1895 if (match(A, m_Or(m_Value(V1), m_Specific(B))) ||
1896 match(A, m_Or(m_Specific(B), m_Value(V1)))) {
1897 Instruction *Ret = FoldOrWithConstants(I, Op1, V1, B, C);
1898 if (Ret) return Ret;
1900 // (B&-2)|((A|B)&1) -> (A&1) | B
1901 if (match(B, m_Or(m_Specific(A), m_Value(V1))) ||
1902 match(B, m_Or(m_Value(V1), m_Specific(A)))) {
1903 Instruction *Ret = FoldOrWithConstants(I, Op0, A, V1, D);
1904 if (Ret) return Ret;
1908 // (X >> Z) | (Y >> Z) -> (X|Y) >> Z for all shifts.
1909 if (BinaryOperator *SI1 = dyn_cast<BinaryOperator>(Op1)) {
1910 if (BinaryOperator *SI0 = dyn_cast<BinaryOperator>(Op0))
1911 if (SI0->isShift() && SI0->getOpcode() == SI1->getOpcode() &&
1912 SI0->getOperand(1) == SI1->getOperand(1) &&
1913 (SI0->hasOneUse() || SI1->hasOneUse())) {
1914 Value *NewOp = Builder->CreateOr(SI0->getOperand(0), SI1->getOperand(0),
1916 return BinaryOperator::Create(SI1->getOpcode(), NewOp,
1917 SI1->getOperand(1));
1921 // (~A | ~B) == (~(A & B)) - De Morgan's Law
1922 if (Value *Op0NotVal = dyn_castNotVal(Op0))
1923 if (Value *Op1NotVal = dyn_castNotVal(Op1))
1924 if (Op0->hasOneUse() && Op1->hasOneUse()) {
1925 Value *And = Builder->CreateAnd(Op0NotVal, Op1NotVal,
1926 I.getName()+".demorgan");
1927 return BinaryOperator::CreateNot(And);
1930 // Canonicalize xor to the RHS.
1931 bool SwappedForXor = false;
1932 if (match(Op0, m_Xor(m_Value(), m_Value()))) {
1933 std::swap(Op0, Op1);
1934 SwappedForXor = true;
1937 // A | ( A ^ B) -> A | B
1938 // A | (~A ^ B) -> A | ~B
1939 // (A & B) | (A ^ B)
1940 if (match(Op1, m_Xor(m_Value(A), m_Value(B)))) {
1941 if (Op0 == A || Op0 == B)
1942 return BinaryOperator::CreateOr(A, B);
1944 if (match(Op0, m_And(m_Specific(A), m_Specific(B))) ||
1945 match(Op0, m_And(m_Specific(B), m_Specific(A))))
1946 return BinaryOperator::CreateOr(A, B);
1948 if (Op1->hasOneUse() && match(A, m_Not(m_Specific(Op0)))) {
1949 Value *Not = Builder->CreateNot(B, B->getName()+".not");
1950 return BinaryOperator::CreateOr(Not, Op0);
1952 if (Op1->hasOneUse() && match(B, m_Not(m_Specific(Op0)))) {
1953 Value *Not = Builder->CreateNot(A, A->getName()+".not");
1954 return BinaryOperator::CreateOr(Not, Op0);
1958 // A | ~(A | B) -> A | ~B
1959 // A | ~(A ^ B) -> A | ~B
1960 if (match(Op1, m_Not(m_Value(A))))
1961 if (BinaryOperator *B = dyn_cast<BinaryOperator>(A))
1962 if ((Op0 == B->getOperand(0) || Op0 == B->getOperand(1)) &&
1963 Op1->hasOneUse() && (B->getOpcode() == Instruction::Or ||
1964 B->getOpcode() == Instruction::Xor)) {
1965 Value *NotOp = Op0 == B->getOperand(0) ? B->getOperand(1) :
1967 Value *Not = Builder->CreateNot(NotOp, NotOp->getName()+".not");
1968 return BinaryOperator::CreateOr(Not, Op0);
1972 std::swap(Op0, Op1);
1974 if (ICmpInst *RHS = dyn_cast<ICmpInst>(I.getOperand(1)))
1975 if (ICmpInst *LHS = dyn_cast<ICmpInst>(I.getOperand(0)))
1976 if (Value *Res = FoldOrOfICmps(LHS, RHS))
1977 return ReplaceInstUsesWith(I, Res);
1979 // (fcmp uno x, c) | (fcmp uno y, c) -> (fcmp uno x, y)
1980 if (FCmpInst *LHS = dyn_cast<FCmpInst>(I.getOperand(0)))
1981 if (FCmpInst *RHS = dyn_cast<FCmpInst>(I.getOperand(1)))
1982 if (Value *Res = FoldOrOfFCmps(LHS, RHS))
1983 return ReplaceInstUsesWith(I, Res);
1985 // fold (or (cast A), (cast B)) -> (cast (or A, B))
1986 if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
1987 CastInst *Op1C = dyn_cast<CastInst>(Op1);
1988 if (Op1C && Op0C->getOpcode() == Op1C->getOpcode()) {// same cast kind ?
1989 Type *SrcTy = Op0C->getOperand(0)->getType();
1990 if (SrcTy == Op1C->getOperand(0)->getType() &&
1991 SrcTy->isIntOrIntVectorTy()) {
1992 Value *Op0COp = Op0C->getOperand(0), *Op1COp = Op1C->getOperand(0);
1994 if ((!isa<ICmpInst>(Op0COp) || !isa<ICmpInst>(Op1COp)) &&
1995 // Only do this if the casts both really cause code to be
1997 ShouldOptimizeCast(Op0C->getOpcode(), Op0COp, I.getType()) &&
1998 ShouldOptimizeCast(Op1C->getOpcode(), Op1COp, I.getType())) {
1999 Value *NewOp = Builder->CreateOr(Op0COp, Op1COp, I.getName());
2000 return CastInst::Create(Op0C->getOpcode(), NewOp, I.getType());
2003 // If this is or(cast(icmp), cast(icmp)), try to fold this even if the
2004 // cast is otherwise not optimizable. This happens for vector sexts.
2005 if (ICmpInst *RHS = dyn_cast<ICmpInst>(Op1COp))
2006 if (ICmpInst *LHS = dyn_cast<ICmpInst>(Op0COp))
2007 if (Value *Res = FoldOrOfICmps(LHS, RHS))
2008 return CastInst::Create(Op0C->getOpcode(), Res, I.getType());
2010 // If this is or(cast(fcmp), cast(fcmp)), try to fold this even if the
2011 // cast is otherwise not optimizable. This happens for vector sexts.
2012 if (FCmpInst *RHS = dyn_cast<FCmpInst>(Op1COp))
2013 if (FCmpInst *LHS = dyn_cast<FCmpInst>(Op0COp))
2014 if (Value *Res = FoldOrOfFCmps(LHS, RHS))
2015 return CastInst::Create(Op0C->getOpcode(), Res, I.getType());
2020 // or(sext(A), B) -> A ? -1 : B where A is an i1
2021 // or(A, sext(B)) -> B ? -1 : A where B is an i1
2022 if (match(Op0, m_SExt(m_Value(A))) && A->getType()->isIntegerTy(1))
2023 return SelectInst::Create(A, ConstantInt::getSigned(I.getType(), -1), Op1);
2024 if (match(Op1, m_SExt(m_Value(A))) && A->getType()->isIntegerTy(1))
2025 return SelectInst::Create(A, ConstantInt::getSigned(I.getType(), -1), Op0);
2027 // Note: If we've gotten to the point of visiting the outer OR, then the
2028 // inner one couldn't be simplified. If it was a constant, then it won't
2029 // be simplified by a later pass either, so we try swapping the inner/outer
2030 // ORs in the hopes that we'll be able to simplify it this way.
2031 // (X|C) | V --> (X|V) | C
2032 if (Op0->hasOneUse() && !isa<ConstantInt>(Op1) &&
2033 match(Op0, m_Or(m_Value(A), m_ConstantInt(C1)))) {
2034 Value *Inner = Builder->CreateOr(A, Op1);
2035 Inner->takeName(Op0);
2036 return BinaryOperator::CreateOr(Inner, C1);
2039 return Changed ? &I : 0;
2042 Instruction *InstCombiner::visitXor(BinaryOperator &I) {
2043 bool Changed = SimplifyAssociativeOrCommutative(I);
2044 Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
2046 if (Value *V = SimplifyXorInst(Op0, Op1, TD))
2047 return ReplaceInstUsesWith(I, V);
2049 // (A&B)^(A&C) -> A&(B^C) etc
2050 if (Value *V = SimplifyUsingDistributiveLaws(I))
2051 return ReplaceInstUsesWith(I, V);
2053 // See if we can simplify any instructions used by the instruction whose sole
2054 // purpose is to compute bits we don't care about.
2055 if (SimplifyDemandedInstructionBits(I))
2058 // Is this a ~ operation?
2059 if (Value *NotOp = dyn_castNotVal(&I)) {
2060 if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(NotOp)) {
2061 if (Op0I->getOpcode() == Instruction::And ||
2062 Op0I->getOpcode() == Instruction::Or) {
2063 // ~(~X & Y) --> (X | ~Y) - De Morgan's Law
2064 // ~(~X | Y) === (X & ~Y) - De Morgan's Law
2065 if (dyn_castNotVal(Op0I->getOperand(1)))
2066 Op0I->swapOperands();
2067 if (Value *Op0NotVal = dyn_castNotVal(Op0I->getOperand(0))) {
2069 Builder->CreateNot(Op0I->getOperand(1),
2070 Op0I->getOperand(1)->getName()+".not");
2071 if (Op0I->getOpcode() == Instruction::And)
2072 return BinaryOperator::CreateOr(Op0NotVal, NotY);
2073 return BinaryOperator::CreateAnd(Op0NotVal, NotY);
2076 // ~(X & Y) --> (~X | ~Y) - De Morgan's Law
2077 // ~(X | Y) === (~X & ~Y) - De Morgan's Law
2078 if (isFreeToInvert(Op0I->getOperand(0)) &&
2079 isFreeToInvert(Op0I->getOperand(1))) {
2081 Builder->CreateNot(Op0I->getOperand(0), "notlhs");
2083 Builder->CreateNot(Op0I->getOperand(1), "notrhs");
2084 if (Op0I->getOpcode() == Instruction::And)
2085 return BinaryOperator::CreateOr(NotX, NotY);
2086 return BinaryOperator::CreateAnd(NotX, NotY);
2089 } else if (Op0I->getOpcode() == Instruction::AShr) {
2090 // ~(~X >>s Y) --> (X >>s Y)
2091 if (Value *Op0NotVal = dyn_castNotVal(Op0I->getOperand(0)))
2092 return BinaryOperator::CreateAShr(Op0NotVal, Op0I->getOperand(1));
2098 if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
2099 if (RHS->isOne() && Op0->hasOneUse())
2100 // xor (cmp A, B), true = not (cmp A, B) = !cmp A, B
2101 if (CmpInst *CI = dyn_cast<CmpInst>(Op0))
2102 return CmpInst::Create(CI->getOpcode(),
2103 CI->getInversePredicate(),
2104 CI->getOperand(0), CI->getOperand(1));
2106 // fold (xor(zext(cmp)), 1) and (xor(sext(cmp)), -1) to ext(!cmp).
2107 if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
2108 if (CmpInst *CI = dyn_cast<CmpInst>(Op0C->getOperand(0))) {
2109 if (CI->hasOneUse() && Op0C->hasOneUse()) {
2110 Instruction::CastOps Opcode = Op0C->getOpcode();
2111 if ((Opcode == Instruction::ZExt || Opcode == Instruction::SExt) &&
2112 (RHS == ConstantExpr::getCast(Opcode,
2113 ConstantInt::getTrue(I.getContext()),
2114 Op0C->getDestTy()))) {
2115 CI->setPredicate(CI->getInversePredicate());
2116 return CastInst::Create(Opcode, CI, Op0C->getType());
2122 if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
2123 // ~(c-X) == X-c-1 == X+(-c-1)
2124 if (Op0I->getOpcode() == Instruction::Sub && RHS->isAllOnesValue())
2125 if (Constant *Op0I0C = dyn_cast<Constant>(Op0I->getOperand(0))) {
2126 Constant *NegOp0I0C = ConstantExpr::getNeg(Op0I0C);
2127 Constant *ConstantRHS = ConstantExpr::getSub(NegOp0I0C,
2128 ConstantInt::get(I.getType(), 1));
2129 return BinaryOperator::CreateAdd(Op0I->getOperand(1), ConstantRHS);
2132 if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) {
2133 if (Op0I->getOpcode() == Instruction::Add) {
2134 // ~(X-c) --> (-c-1)-X
2135 if (RHS->isAllOnesValue()) {
2136 Constant *NegOp0CI = ConstantExpr::getNeg(Op0CI);
2137 return BinaryOperator::CreateSub(
2138 ConstantExpr::getSub(NegOp0CI,
2139 ConstantInt::get(I.getType(), 1)),
2140 Op0I->getOperand(0));
2141 } else if (RHS->getValue().isSignBit()) {
2142 // (X + C) ^ signbit -> (X + C + signbit)
2143 Constant *C = ConstantInt::get(I.getContext(),
2144 RHS->getValue() + Op0CI->getValue());
2145 return BinaryOperator::CreateAdd(Op0I->getOperand(0), C);
2148 } else if (Op0I->getOpcode() == Instruction::Or) {
2149 // (X|C1)^C2 -> X^(C1|C2) if X&~C1 == 0
2150 if (MaskedValueIsZero(Op0I->getOperand(0), Op0CI->getValue())) {
2151 Constant *NewRHS = ConstantExpr::getOr(Op0CI, RHS);
2152 // Anything in both C1 and C2 is known to be zero, remove it from
2154 Constant *CommonBits = ConstantExpr::getAnd(Op0CI, RHS);
2155 NewRHS = ConstantExpr::getAnd(NewRHS,
2156 ConstantExpr::getNot(CommonBits));
2158 I.setOperand(0, Op0I->getOperand(0));
2159 I.setOperand(1, NewRHS);
2166 // Try to fold constant and into select arguments.
2167 if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
2168 if (Instruction *R = FoldOpIntoSelect(I, SI))
2170 if (isa<PHINode>(Op0))
2171 if (Instruction *NV = FoldOpIntoPhi(I))
2175 BinaryOperator *Op1I = dyn_cast<BinaryOperator>(Op1);
2178 if (match(Op1I, m_Or(m_Value(A), m_Value(B)))) {
2179 if (A == Op0) { // B^(B|A) == (A|B)^B
2180 Op1I->swapOperands();
2182 std::swap(Op0, Op1);
2183 } else if (B == Op0) { // B^(A|B) == (A|B)^B
2184 I.swapOperands(); // Simplified below.
2185 std::swap(Op0, Op1);
2187 } else if (match(Op1I, m_And(m_Value(A), m_Value(B))) &&
2189 if (A == Op0) { // A^(A&B) -> A^(B&A)
2190 Op1I->swapOperands();
2193 if (B == Op0) { // A^(B&A) -> (B&A)^A
2194 I.swapOperands(); // Simplified below.
2195 std::swap(Op0, Op1);
2200 BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0);
2203 if (match(Op0I, m_Or(m_Value(A), m_Value(B))) &&
2204 Op0I->hasOneUse()) {
2205 if (A == Op1) // (B|A)^B == (A|B)^B
2207 if (B == Op1) // (A|B)^B == A & ~B
2208 return BinaryOperator::CreateAnd(A, Builder->CreateNot(Op1));
2209 } else if (match(Op0I, m_And(m_Value(A), m_Value(B))) &&
2211 if (A == Op1) // (A&B)^A -> (B&A)^A
2213 if (B == Op1 && // (B&A)^A == ~B & A
2214 !isa<ConstantInt>(Op1)) { // Canonical form is (B&C)^C
2215 return BinaryOperator::CreateAnd(Builder->CreateNot(A), Op1);
2220 // (X >> Z) ^ (Y >> Z) -> (X^Y) >> Z for all shifts.
2221 if (Op0I && Op1I && Op0I->isShift() &&
2222 Op0I->getOpcode() == Op1I->getOpcode() &&
2223 Op0I->getOperand(1) == Op1I->getOperand(1) &&
2224 (Op0I->hasOneUse() || Op1I->hasOneUse())) {
2226 Builder->CreateXor(Op0I->getOperand(0), Op1I->getOperand(0),
2228 return BinaryOperator::Create(Op1I->getOpcode(), NewOp,
2229 Op1I->getOperand(1));
2233 Value *A, *B, *C, *D;
2234 // (A & B)^(A | B) -> A ^ B
2235 if (match(Op0I, m_And(m_Value(A), m_Value(B))) &&
2236 match(Op1I, m_Or(m_Value(C), m_Value(D)))) {
2237 if ((A == C && B == D) || (A == D && B == C))
2238 return BinaryOperator::CreateXor(A, B);
2240 // (A | B)^(A & B) -> A ^ B
2241 if (match(Op0I, m_Or(m_Value(A), m_Value(B))) &&
2242 match(Op1I, m_And(m_Value(C), m_Value(D)))) {
2243 if ((A == C && B == D) || (A == D && B == C))
2244 return BinaryOperator::CreateXor(A, B);
2248 // (icmp1 A, B) ^ (icmp2 A, B) --> (icmp3 A, B)
2249 if (ICmpInst *RHS = dyn_cast<ICmpInst>(I.getOperand(1)))
2250 if (ICmpInst *LHS = dyn_cast<ICmpInst>(I.getOperand(0)))
2251 if (PredicatesFoldable(LHS->getPredicate(), RHS->getPredicate())) {
2252 if (LHS->getOperand(0) == RHS->getOperand(1) &&
2253 LHS->getOperand(1) == RHS->getOperand(0))
2254 LHS->swapOperands();
2255 if (LHS->getOperand(0) == RHS->getOperand(0) &&
2256 LHS->getOperand(1) == RHS->getOperand(1)) {
2257 Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1);
2258 unsigned Code = getICmpCode(LHS) ^ getICmpCode(RHS);
2259 bool isSigned = LHS->isSigned() || RHS->isSigned();
2260 return ReplaceInstUsesWith(I,
2261 getNewICmpValue(isSigned, Code, Op0, Op1,
2266 // fold (xor (cast A), (cast B)) -> (cast (xor A, B))
2267 if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
2268 if (CastInst *Op1C = dyn_cast<CastInst>(Op1))
2269 if (Op0C->getOpcode() == Op1C->getOpcode()) { // same cast kind?
2270 Type *SrcTy = Op0C->getOperand(0)->getType();
2271 if (SrcTy == Op1C->getOperand(0)->getType() && SrcTy->isIntegerTy() &&
2272 // Only do this if the casts both really cause code to be generated.
2273 ShouldOptimizeCast(Op0C->getOpcode(), Op0C->getOperand(0),
2275 ShouldOptimizeCast(Op1C->getOpcode(), Op1C->getOperand(0),
2277 Value *NewOp = Builder->CreateXor(Op0C->getOperand(0),
2278 Op1C->getOperand(0), I.getName());
2279 return CastInst::Create(Op0C->getOpcode(), NewOp, I.getType());
2284 return Changed ? &I : 0;