LLVM 19.0.0git
InstCombineAndOrXor.cpp
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1//===- InstCombineAndOrXor.cpp --------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements the visitAnd, visitOr, and visitXor functions.
10//
11//===----------------------------------------------------------------------===//
12
13#include "InstCombineInternal.h"
17#include "llvm/IR/Intrinsics.h"
21
22using namespace llvm;
23using namespace PatternMatch;
24
25#define DEBUG_TYPE "instcombine"
26
27/// This is the complement of getICmpCode, which turns an opcode and two
28/// operands into either a constant true or false, or a brand new ICmp
29/// instruction. The sign is passed in to determine which kind of predicate to
30/// use in the new icmp instruction.
31static Value *getNewICmpValue(unsigned Code, bool Sign, Value *LHS, Value *RHS,
32 InstCombiner::BuilderTy &Builder) {
33 ICmpInst::Predicate NewPred;
34 if (Constant *TorF = getPredForICmpCode(Code, Sign, LHS->getType(), NewPred))
35 return TorF;
36 return Builder.CreateICmp(NewPred, LHS, RHS);
37}
38
39/// This is the complement of getFCmpCode, which turns an opcode and two
40/// operands into either a FCmp instruction, or a true/false constant.
41static Value *getFCmpValue(unsigned Code, Value *LHS, Value *RHS,
42 InstCombiner::BuilderTy &Builder) {
43 FCmpInst::Predicate NewPred;
44 if (Constant *TorF = getPredForFCmpCode(Code, LHS->getType(), NewPred))
45 return TorF;
46 return Builder.CreateFCmp(NewPred, LHS, RHS);
47}
48
49/// Emit a computation of: (V >= Lo && V < Hi) if Inside is true, otherwise
50/// (V < Lo || V >= Hi). This method expects that Lo < Hi. IsSigned indicates
51/// whether to treat V, Lo, and Hi as signed or not.
53 const APInt &Hi, bool isSigned,
54 bool Inside) {
55 assert((isSigned ? Lo.slt(Hi) : Lo.ult(Hi)) &&
56 "Lo is not < Hi in range emission code!");
57
58 Type *Ty = V->getType();
59
60 // V >= Min && V < Hi --> V < Hi
61 // V < Min || V >= Hi --> V >= Hi
63 if (isSigned ? Lo.isMinSignedValue() : Lo.isMinValue()) {
64 Pred = isSigned ? ICmpInst::getSignedPredicate(Pred) : Pred;
65 return Builder.CreateICmp(Pred, V, ConstantInt::get(Ty, Hi));
66 }
67
68 // V >= Lo && V < Hi --> V - Lo u< Hi - Lo
69 // V < Lo || V >= Hi --> V - Lo u>= Hi - Lo
70 Value *VMinusLo =
71 Builder.CreateSub(V, ConstantInt::get(Ty, Lo), V->getName() + ".off");
72 Constant *HiMinusLo = ConstantInt::get(Ty, Hi - Lo);
73 return Builder.CreateICmp(Pred, VMinusLo, HiMinusLo);
74}
75
76/// Classify (icmp eq (A & B), C) and (icmp ne (A & B), C) as matching patterns
77/// that can be simplified.
78/// One of A and B is considered the mask. The other is the value. This is
79/// described as the "AMask" or "BMask" part of the enum. If the enum contains
80/// only "Mask", then both A and B can be considered masks. If A is the mask,
81/// then it was proven that (A & C) == C. This is trivial if C == A or C == 0.
82/// If both A and C are constants, this proof is also easy.
83/// For the following explanations, we assume that A is the mask.
84///
85/// "AllOnes" declares that the comparison is true only if (A & B) == A or all
86/// bits of A are set in B.
87/// Example: (icmp eq (A & 3), 3) -> AMask_AllOnes
88///
89/// "AllZeros" declares that the comparison is true only if (A & B) == 0 or all
90/// bits of A are cleared in B.
91/// Example: (icmp eq (A & 3), 0) -> Mask_AllZeroes
92///
93/// "Mixed" declares that (A & B) == C and C might or might not contain any
94/// number of one bits and zero bits.
95/// Example: (icmp eq (A & 3), 1) -> AMask_Mixed
96///
97/// "Not" means that in above descriptions "==" should be replaced by "!=".
98/// Example: (icmp ne (A & 3), 3) -> AMask_NotAllOnes
99///
100/// If the mask A contains a single bit, then the following is equivalent:
101/// (icmp eq (A & B), A) equals (icmp ne (A & B), 0)
102/// (icmp ne (A & B), A) equals (icmp eq (A & B), 0)
113 BMask_NotMixed = 512
115
116/// Return the set of patterns (from MaskedICmpType) that (icmp SCC (A & B), C)
117/// satisfies.
118static unsigned getMaskedICmpType(Value *A, Value *B, Value *C,
119 ICmpInst::Predicate Pred) {
120 const APInt *ConstA = nullptr, *ConstB = nullptr, *ConstC = nullptr;
121 match(A, m_APInt(ConstA));
122 match(B, m_APInt(ConstB));
123 match(C, m_APInt(ConstC));
124 bool IsEq = (Pred == ICmpInst::ICMP_EQ);
125 bool IsAPow2 = ConstA && ConstA->isPowerOf2();
126 bool IsBPow2 = ConstB && ConstB->isPowerOf2();
127 unsigned MaskVal = 0;
128 if (ConstC && ConstC->isZero()) {
129 // if C is zero, then both A and B qualify as mask
130 MaskVal |= (IsEq ? (Mask_AllZeros | AMask_Mixed | BMask_Mixed)
132 if (IsAPow2)
133 MaskVal |= (IsEq ? (AMask_NotAllOnes | AMask_NotMixed)
135 if (IsBPow2)
136 MaskVal |= (IsEq ? (BMask_NotAllOnes | BMask_NotMixed)
138 return MaskVal;
139 }
140
141 if (A == C) {
142 MaskVal |= (IsEq ? (AMask_AllOnes | AMask_Mixed)
144 if (IsAPow2)
145 MaskVal |= (IsEq ? (Mask_NotAllZeros | AMask_NotMixed)
147 } else if (ConstA && ConstC && ConstC->isSubsetOf(*ConstA)) {
148 MaskVal |= (IsEq ? AMask_Mixed : AMask_NotMixed);
149 }
150
151 if (B == C) {
152 MaskVal |= (IsEq ? (BMask_AllOnes | BMask_Mixed)
154 if (IsBPow2)
155 MaskVal |= (IsEq ? (Mask_NotAllZeros | BMask_NotMixed)
157 } else if (ConstB && ConstC && ConstC->isSubsetOf(*ConstB)) {
158 MaskVal |= (IsEq ? BMask_Mixed : BMask_NotMixed);
159 }
160
161 return MaskVal;
162}
163
164/// Convert an analysis of a masked ICmp into its equivalent if all boolean
165/// operations had the opposite sense. Since each "NotXXX" flag (recording !=)
166/// is adjacent to the corresponding normal flag (recording ==), this just
167/// involves swapping those bits over.
168static unsigned conjugateICmpMask(unsigned Mask) {
169 unsigned NewMask;
170 NewMask = (Mask & (AMask_AllOnes | BMask_AllOnes | Mask_AllZeros |
172 << 1;
173
174 NewMask |= (Mask & (AMask_NotAllOnes | BMask_NotAllOnes | Mask_NotAllZeros |
176 >> 1;
177
178 return NewMask;
179}
180
181// Adapts the external decomposeBitTestICmp for local use.
183 Value *&X, Value *&Y, Value *&Z) {
184 APInt Mask;
185 if (!llvm::decomposeBitTestICmp(LHS, RHS, Pred, X, Mask))
186 return false;
187
188 Y = ConstantInt::get(X->getType(), Mask);
189 Z = ConstantInt::get(X->getType(), 0);
190 return true;
191}
192
193/// Handle (icmp(A & B) ==/!= C) &/| (icmp(A & D) ==/!= E).
194/// Return the pattern classes (from MaskedICmpType) for the left hand side and
195/// the right hand side as a pair.
196/// LHS and RHS are the left hand side and the right hand side ICmps and PredL
197/// and PredR are their predicates, respectively.
198static std::optional<std::pair<unsigned, unsigned>> getMaskedTypeForICmpPair(
199 Value *&A, Value *&B, Value *&C, Value *&D, Value *&E, ICmpInst *LHS,
200 ICmpInst *RHS, ICmpInst::Predicate &PredL, ICmpInst::Predicate &PredR) {
201 // Don't allow pointers. Splat vectors are fine.
202 if (!LHS->getOperand(0)->getType()->isIntOrIntVectorTy() ||
203 !RHS->getOperand(0)->getType()->isIntOrIntVectorTy())
204 return std::nullopt;
205
206 // Here comes the tricky part:
207 // LHS might be of the form L11 & L12 == X, X == L21 & L22,
208 // and L11 & L12 == L21 & L22. The same goes for RHS.
209 // Now we must find those components L** and R**, that are equal, so
210 // that we can extract the parameters A, B, C, D, and E for the canonical
211 // above.
212 Value *L1 = LHS->getOperand(0);
213 Value *L2 = LHS->getOperand(1);
214 Value *L11, *L12, *L21, *L22;
215 // Check whether the icmp can be decomposed into a bit test.
216 if (decomposeBitTestICmp(L1, L2, PredL, L11, L12, L2)) {
217 L21 = L22 = L1 = nullptr;
218 } else {
219 // Look for ANDs in the LHS icmp.
220 if (!match(L1, m_And(m_Value(L11), m_Value(L12)))) {
221 // Any icmp can be viewed as being trivially masked; if it allows us to
222 // remove one, it's worth it.
223 L11 = L1;
225 }
226
227 if (!match(L2, m_And(m_Value(L21), m_Value(L22)))) {
228 L21 = L2;
230 }
231 }
232
233 // Bail if LHS was a icmp that can't be decomposed into an equality.
234 if (!ICmpInst::isEquality(PredL))
235 return std::nullopt;
236
237 Value *R1 = RHS->getOperand(0);
238 Value *R2 = RHS->getOperand(1);
239 Value *R11, *R12;
240 bool Ok = false;
241 if (decomposeBitTestICmp(R1, R2, PredR, R11, R12, R2)) {
242 if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
243 A = R11;
244 D = R12;
245 } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
246 A = R12;
247 D = R11;
248 } else {
249 return std::nullopt;
250 }
251 E = R2;
252 R1 = nullptr;
253 Ok = true;
254 } else {
255 if (!match(R1, m_And(m_Value(R11), m_Value(R12)))) {
256 // As before, model no mask as a trivial mask if it'll let us do an
257 // optimization.
258 R11 = R1;
260 }
261
262 if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
263 A = R11;
264 D = R12;
265 E = R2;
266 Ok = true;
267 } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
268 A = R12;
269 D = R11;
270 E = R2;
271 Ok = true;
272 }
273 }
274
275 // Bail if RHS was a icmp that can't be decomposed into an equality.
276 if (!ICmpInst::isEquality(PredR))
277 return std::nullopt;
278
279 // Look for ANDs on the right side of the RHS icmp.
280 if (!Ok) {
281 if (!match(R2, m_And(m_Value(R11), m_Value(R12)))) {
282 R11 = R2;
283 R12 = Constant::getAllOnesValue(R2->getType());
284 }
285
286 if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
287 A = R11;
288 D = R12;
289 E = R1;
290 Ok = true;
291 } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
292 A = R12;
293 D = R11;
294 E = R1;
295 Ok = true;
296 } else {
297 return std::nullopt;
298 }
299
300 assert(Ok && "Failed to find AND on the right side of the RHS icmp.");
301 }
302
303 if (L11 == A) {
304 B = L12;
305 C = L2;
306 } else if (L12 == A) {
307 B = L11;
308 C = L2;
309 } else if (L21 == A) {
310 B = L22;
311 C = L1;
312 } else if (L22 == A) {
313 B = L21;
314 C = L1;
315 }
316
317 unsigned LeftType = getMaskedICmpType(A, B, C, PredL);
318 unsigned RightType = getMaskedICmpType(A, D, E, PredR);
319 return std::optional<std::pair<unsigned, unsigned>>(
320 std::make_pair(LeftType, RightType));
321}
322
323/// Try to fold (icmp(A & B) ==/!= C) &/| (icmp(A & D) ==/!= E) into a single
324/// (icmp(A & X) ==/!= Y), where the left-hand side is of type Mask_NotAllZeros
325/// and the right hand side is of type BMask_Mixed. For example,
326/// (icmp (A & 12) != 0) & (icmp (A & 15) == 8) -> (icmp (A & 15) == 8).
327/// Also used for logical and/or, must be poison safe.
329 ICmpInst *LHS, ICmpInst *RHS, bool IsAnd, Value *A, Value *B, Value *C,
331 InstCombiner::BuilderTy &Builder) {
332 // We are given the canonical form:
333 // (icmp ne (A & B), 0) & (icmp eq (A & D), E).
334 // where D & E == E.
335 //
336 // If IsAnd is false, we get it in negated form:
337 // (icmp eq (A & B), 0) | (icmp ne (A & D), E) ->
338 // !((icmp ne (A & B), 0) & (icmp eq (A & D), E)).
339 //
340 // We currently handle the case of B, C, D, E are constant.
341 //
342 const APInt *BCst, *CCst, *DCst, *OrigECst;
343 if (!match(B, m_APInt(BCst)) || !match(C, m_APInt(CCst)) ||
344 !match(D, m_APInt(DCst)) || !match(E, m_APInt(OrigECst)))
345 return nullptr;
346
348
349 // Update E to the canonical form when D is a power of two and RHS is
350 // canonicalized as,
351 // (icmp ne (A & D), 0) -> (icmp eq (A & D), D) or
352 // (icmp ne (A & D), D) -> (icmp eq (A & D), 0).
353 APInt ECst = *OrigECst;
354 if (PredR != NewCC)
355 ECst ^= *DCst;
356
357 // If B or D is zero, skip because if LHS or RHS can be trivially folded by
358 // other folding rules and this pattern won't apply any more.
359 if (*BCst == 0 || *DCst == 0)
360 return nullptr;
361
362 // If B and D don't intersect, ie. (B & D) == 0, no folding because we can't
363 // deduce anything from it.
364 // For example,
365 // (icmp ne (A & 12), 0) & (icmp eq (A & 3), 1) -> no folding.
366 if ((*BCst & *DCst) == 0)
367 return nullptr;
368
369 // If the following two conditions are met:
370 //
371 // 1. mask B covers only a single bit that's not covered by mask D, that is,
372 // (B & (B ^ D)) is a power of 2 (in other words, B minus the intersection of
373 // B and D has only one bit set) and,
374 //
375 // 2. RHS (and E) indicates that the rest of B's bits are zero (in other
376 // words, the intersection of B and D is zero), that is, ((B & D) & E) == 0
377 //
378 // then that single bit in B must be one and thus the whole expression can be
379 // folded to
380 // (A & (B | D)) == (B & (B ^ D)) | E.
381 //
382 // For example,
383 // (icmp ne (A & 12), 0) & (icmp eq (A & 7), 1) -> (icmp eq (A & 15), 9)
384 // (icmp ne (A & 15), 0) & (icmp eq (A & 7), 0) -> (icmp eq (A & 15), 8)
385 if ((((*BCst & *DCst) & ECst) == 0) &&
386 (*BCst & (*BCst ^ *DCst)).isPowerOf2()) {
387 APInt BorD = *BCst | *DCst;
388 APInt BandBxorDorE = (*BCst & (*BCst ^ *DCst)) | ECst;
389 Value *NewMask = ConstantInt::get(A->getType(), BorD);
390 Value *NewMaskedValue = ConstantInt::get(A->getType(), BandBxorDorE);
391 Value *NewAnd = Builder.CreateAnd(A, NewMask);
392 return Builder.CreateICmp(NewCC, NewAnd, NewMaskedValue);
393 }
394
395 auto IsSubSetOrEqual = [](const APInt *C1, const APInt *C2) {
396 return (*C1 & *C2) == *C1;
397 };
398 auto IsSuperSetOrEqual = [](const APInt *C1, const APInt *C2) {
399 return (*C1 & *C2) == *C2;
400 };
401
402 // In the following, we consider only the cases where B is a superset of D, B
403 // is a subset of D, or B == D because otherwise there's at least one bit
404 // covered by B but not D, in which case we can't deduce much from it, so
405 // no folding (aside from the single must-be-one bit case right above.)
406 // For example,
407 // (icmp ne (A & 14), 0) & (icmp eq (A & 3), 1) -> no folding.
408 if (!IsSubSetOrEqual(BCst, DCst) && !IsSuperSetOrEqual(BCst, DCst))
409 return nullptr;
410
411 // At this point, either B is a superset of D, B is a subset of D or B == D.
412
413 // If E is zero, if B is a subset of (or equal to) D, LHS and RHS contradict
414 // and the whole expression becomes false (or true if negated), otherwise, no
415 // folding.
416 // For example,
417 // (icmp ne (A & 3), 0) & (icmp eq (A & 7), 0) -> false.
418 // (icmp ne (A & 15), 0) & (icmp eq (A & 3), 0) -> no folding.
419 if (ECst.isZero()) {
420 if (IsSubSetOrEqual(BCst, DCst))
421 return ConstantInt::get(LHS->getType(), !IsAnd);
422 return nullptr;
423 }
424
425 // At this point, B, D, E aren't zero and (B & D) == B, (B & D) == D or B ==
426 // D. If B is a superset of (or equal to) D, since E is not zero, LHS is
427 // subsumed by RHS (RHS implies LHS.) So the whole expression becomes
428 // RHS. For example,
429 // (icmp ne (A & 255), 0) & (icmp eq (A & 15), 8) -> (icmp eq (A & 15), 8).
430 // (icmp ne (A & 15), 0) & (icmp eq (A & 15), 8) -> (icmp eq (A & 15), 8).
431 if (IsSuperSetOrEqual(BCst, DCst))
432 return RHS;
433 // Otherwise, B is a subset of D. If B and E have a common bit set,
434 // ie. (B & E) != 0, then LHS is subsumed by RHS. For example.
435 // (icmp ne (A & 12), 0) & (icmp eq (A & 15), 8) -> (icmp eq (A & 15), 8).
436 assert(IsSubSetOrEqual(BCst, DCst) && "Precondition due to above code");
437 if ((*BCst & ECst) != 0)
438 return RHS;
439 // Otherwise, LHS and RHS contradict and the whole expression becomes false
440 // (or true if negated.) For example,
441 // (icmp ne (A & 7), 0) & (icmp eq (A & 15), 8) -> false.
442 // (icmp ne (A & 6), 0) & (icmp eq (A & 15), 8) -> false.
443 return ConstantInt::get(LHS->getType(), !IsAnd);
444}
445
446/// Try to fold (icmp(A & B) ==/!= 0) &/| (icmp(A & D) ==/!= E) into a single
447/// (icmp(A & X) ==/!= Y), where the left-hand side and the right hand side
448/// aren't of the common mask pattern type.
449/// Also used for logical and/or, must be poison safe.
451 ICmpInst *LHS, ICmpInst *RHS, bool IsAnd, Value *A, Value *B, Value *C,
453 unsigned LHSMask, unsigned RHSMask, InstCombiner::BuilderTy &Builder) {
455 "Expected equality predicates for masked type of icmps.");
456 // Handle Mask_NotAllZeros-BMask_Mixed cases.
457 // (icmp ne/eq (A & B), C) &/| (icmp eq/ne (A & D), E), or
458 // (icmp eq/ne (A & B), C) &/| (icmp ne/eq (A & D), E)
459 // which gets swapped to
460 // (icmp ne/eq (A & D), E) &/| (icmp eq/ne (A & B), C).
461 if (!IsAnd) {
462 LHSMask = conjugateICmpMask(LHSMask);
463 RHSMask = conjugateICmpMask(RHSMask);
464 }
465 if ((LHSMask & Mask_NotAllZeros) && (RHSMask & BMask_Mixed)) {
467 LHS, RHS, IsAnd, A, B, C, D, E,
468 PredL, PredR, Builder)) {
469 return V;
470 }
471 } else if ((LHSMask & BMask_Mixed) && (RHSMask & Mask_NotAllZeros)) {
473 RHS, LHS, IsAnd, A, D, E, B, C,
474 PredR, PredL, Builder)) {
475 return V;
476 }
477 }
478 return nullptr;
479}
480
481/// Try to fold (icmp(A & B) ==/!= C) &/| (icmp(A & D) ==/!= E)
482/// into a single (icmp(A & X) ==/!= Y).
483static Value *foldLogOpOfMaskedICmps(ICmpInst *LHS, ICmpInst *RHS, bool IsAnd,
484 bool IsLogical,
485 InstCombiner::BuilderTy &Builder) {
486 Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr, *E = nullptr;
487 ICmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
488 std::optional<std::pair<unsigned, unsigned>> MaskPair =
489 getMaskedTypeForICmpPair(A, B, C, D, E, LHS, RHS, PredL, PredR);
490 if (!MaskPair)
491 return nullptr;
493 "Expected equality predicates for masked type of icmps.");
494 unsigned LHSMask = MaskPair->first;
495 unsigned RHSMask = MaskPair->second;
496 unsigned Mask = LHSMask & RHSMask;
497 if (Mask == 0) {
498 // Even if the two sides don't share a common pattern, check if folding can
499 // still happen.
501 LHS, RHS, IsAnd, A, B, C, D, E, PredL, PredR, LHSMask, RHSMask,
502 Builder))
503 return V;
504 return nullptr;
505 }
506
507 // In full generality:
508 // (icmp (A & B) Op C) | (icmp (A & D) Op E)
509 // == ![ (icmp (A & B) !Op C) & (icmp (A & D) !Op E) ]
510 //
511 // If the latter can be converted into (icmp (A & X) Op Y) then the former is
512 // equivalent to (icmp (A & X) !Op Y).
513 //
514 // Therefore, we can pretend for the rest of this function that we're dealing
515 // with the conjunction, provided we flip the sense of any comparisons (both
516 // input and output).
517
518 // In most cases we're going to produce an EQ for the "&&" case.
520 if (!IsAnd) {
521 // Convert the masking analysis into its equivalent with negated
522 // comparisons.
523 Mask = conjugateICmpMask(Mask);
524 }
525
526 if (Mask & Mask_AllZeros) {
527 // (icmp eq (A & B), 0) & (icmp eq (A & D), 0)
528 // -> (icmp eq (A & (B|D)), 0)
529 if (IsLogical && !isGuaranteedNotToBeUndefOrPoison(D))
530 return nullptr; // TODO: Use freeze?
531 Value *NewOr = Builder.CreateOr(B, D);
532 Value *NewAnd = Builder.CreateAnd(A, NewOr);
533 // We can't use C as zero because we might actually handle
534 // (icmp ne (A & B), B) & (icmp ne (A & D), D)
535 // with B and D, having a single bit set.
536 Value *Zero = Constant::getNullValue(A->getType());
537 return Builder.CreateICmp(NewCC, NewAnd, Zero);
538 }
539 if (Mask & BMask_AllOnes) {
540 // (icmp eq (A & B), B) & (icmp eq (A & D), D)
541 // -> (icmp eq (A & (B|D)), (B|D))
542 if (IsLogical && !isGuaranteedNotToBeUndefOrPoison(D))
543 return nullptr; // TODO: Use freeze?
544 Value *NewOr = Builder.CreateOr(B, D);
545 Value *NewAnd = Builder.CreateAnd(A, NewOr);
546 return Builder.CreateICmp(NewCC, NewAnd, NewOr);
547 }
548 if (Mask & AMask_AllOnes) {
549 // (icmp eq (A & B), A) & (icmp eq (A & D), A)
550 // -> (icmp eq (A & (B&D)), A)
551 if (IsLogical && !isGuaranteedNotToBeUndefOrPoison(D))
552 return nullptr; // TODO: Use freeze?
553 Value *NewAnd1 = Builder.CreateAnd(B, D);
554 Value *NewAnd2 = Builder.CreateAnd(A, NewAnd1);
555 return Builder.CreateICmp(NewCC, NewAnd2, A);
556 }
557
558 // Remaining cases assume at least that B and D are constant, and depend on
559 // their actual values. This isn't strictly necessary, just a "handle the
560 // easy cases for now" decision.
561 const APInt *ConstB, *ConstD;
562 if (!match(B, m_APInt(ConstB)) || !match(D, m_APInt(ConstD)))
563 return nullptr;
564
565 if (Mask & (Mask_NotAllZeros | BMask_NotAllOnes)) {
566 // (icmp ne (A & B), 0) & (icmp ne (A & D), 0) and
567 // (icmp ne (A & B), B) & (icmp ne (A & D), D)
568 // -> (icmp ne (A & B), 0) or (icmp ne (A & D), 0)
569 // Only valid if one of the masks is a superset of the other (check "B&D" is
570 // the same as either B or D).
571 APInt NewMask = *ConstB & *ConstD;
572 if (NewMask == *ConstB)
573 return LHS;
574 else if (NewMask == *ConstD)
575 return RHS;
576 }
577
578 if (Mask & AMask_NotAllOnes) {
579 // (icmp ne (A & B), B) & (icmp ne (A & D), D)
580 // -> (icmp ne (A & B), A) or (icmp ne (A & D), A)
581 // Only valid if one of the masks is a superset of the other (check "B|D" is
582 // the same as either B or D).
583 APInt NewMask = *ConstB | *ConstD;
584 if (NewMask == *ConstB)
585 return LHS;
586 else if (NewMask == *ConstD)
587 return RHS;
588 }
589
590 if (Mask & (BMask_Mixed | BMask_NotMixed)) {
591 // Mixed:
592 // (icmp eq (A & B), C) & (icmp eq (A & D), E)
593 // We already know that B & C == C && D & E == E.
594 // If we can prove that (B & D) & (C ^ E) == 0, that is, the bits of
595 // C and E, which are shared by both the mask B and the mask D, don't
596 // contradict, then we can transform to
597 // -> (icmp eq (A & (B|D)), (C|E))
598 // Currently, we only handle the case of B, C, D, and E being constant.
599 // We can't simply use C and E because we might actually handle
600 // (icmp ne (A & B), B) & (icmp eq (A & D), D)
601 // with B and D, having a single bit set.
602
603 // NotMixed:
604 // (icmp ne (A & B), C) & (icmp ne (A & D), E)
605 // -> (icmp ne (A & (B & D)), (C & E))
606 // Check the intersection (B & D) for inequality.
607 // Assume that (B & D) == B || (B & D) == D, i.e B/D is a subset of D/B
608 // and (B & D) & (C ^ E) == 0, bits of C and E, which are shared by both the
609 // B and the D, don't contradict.
610 // Note that we can assume (~B & C) == 0 && (~D & E) == 0, previous
611 // operation should delete these icmps if it hadn't been met.
612
613 const APInt *OldConstC, *OldConstE;
614 if (!match(C, m_APInt(OldConstC)) || !match(E, m_APInt(OldConstE)))
615 return nullptr;
616
617 auto FoldBMixed = [&](ICmpInst::Predicate CC, bool IsNot) -> Value * {
619 const APInt ConstC = PredL != CC ? *ConstB ^ *OldConstC : *OldConstC;
620 const APInt ConstE = PredR != CC ? *ConstD ^ *OldConstE : *OldConstE;
621
622 if (((*ConstB & *ConstD) & (ConstC ^ ConstE)).getBoolValue())
623 return IsNot ? nullptr : ConstantInt::get(LHS->getType(), !IsAnd);
624
625 if (IsNot && !ConstB->isSubsetOf(*ConstD) && !ConstD->isSubsetOf(*ConstB))
626 return nullptr;
627
628 APInt BD, CE;
629 if (IsNot) {
630 BD = *ConstB & *ConstD;
631 CE = ConstC & ConstE;
632 } else {
633 BD = *ConstB | *ConstD;
634 CE = ConstC | ConstE;
635 }
636 Value *NewAnd = Builder.CreateAnd(A, BD);
637 Value *CEVal = ConstantInt::get(A->getType(), CE);
638 return Builder.CreateICmp(CC, CEVal, NewAnd);
639 };
640
641 if (Mask & BMask_Mixed)
642 return FoldBMixed(NewCC, false);
643 if (Mask & BMask_NotMixed) // can be else also
644 return FoldBMixed(NewCC, true);
645 }
646 return nullptr;
647}
648
649/// Try to fold a signed range checked with lower bound 0 to an unsigned icmp.
650/// Example: (icmp sge x, 0) & (icmp slt x, n) --> icmp ult x, n
651/// If \p Inverted is true then the check is for the inverted range, e.g.
652/// (icmp slt x, 0) | (icmp sgt x, n) --> icmp ugt x, n
654 bool Inverted) {
655 // Check the lower range comparison, e.g. x >= 0
656 // InstCombine already ensured that if there is a constant it's on the RHS.
657 ConstantInt *RangeStart = dyn_cast<ConstantInt>(Cmp0->getOperand(1));
658 if (!RangeStart)
659 return nullptr;
660
661 ICmpInst::Predicate Pred0 = (Inverted ? Cmp0->getInversePredicate() :
662 Cmp0->getPredicate());
663
664 // Accept x > -1 or x >= 0 (after potentially inverting the predicate).
665 if (!((Pred0 == ICmpInst::ICMP_SGT && RangeStart->isMinusOne()) ||
666 (Pred0 == ICmpInst::ICMP_SGE && RangeStart->isZero())))
667 return nullptr;
668
669 ICmpInst::Predicate Pred1 = (Inverted ? Cmp1->getInversePredicate() :
670 Cmp1->getPredicate());
671
672 Value *Input = Cmp0->getOperand(0);
673 Value *RangeEnd;
674 if (Cmp1->getOperand(0) == Input) {
675 // For the upper range compare we have: icmp x, n
676 RangeEnd = Cmp1->getOperand(1);
677 } else if (Cmp1->getOperand(1) == Input) {
678 // For the upper range compare we have: icmp n, x
679 RangeEnd = Cmp1->getOperand(0);
680 Pred1 = ICmpInst::getSwappedPredicate(Pred1);
681 } else {
682 return nullptr;
683 }
684
685 // Check the upper range comparison, e.g. x < n
686 ICmpInst::Predicate NewPred;
687 switch (Pred1) {
688 case ICmpInst::ICMP_SLT: NewPred = ICmpInst::ICMP_ULT; break;
689 case ICmpInst::ICMP_SLE: NewPred = ICmpInst::ICMP_ULE; break;
690 default: return nullptr;
691 }
692
693 // This simplification is only valid if the upper range is not negative.
694 KnownBits Known = computeKnownBits(RangeEnd, /*Depth=*/0, Cmp1);
695 if (!Known.isNonNegative())
696 return nullptr;
697
698 if (Inverted)
699 NewPred = ICmpInst::getInversePredicate(NewPred);
700
701 return Builder.CreateICmp(NewPred, Input, RangeEnd);
702}
703
704// Fold (iszero(A & K1) | iszero(A & K2)) -> (A & (K1 | K2)) != (K1 | K2)
705// Fold (!iszero(A & K1) & !iszero(A & K2)) -> (A & (K1 | K2)) == (K1 | K2)
706Value *InstCombinerImpl::foldAndOrOfICmpsOfAndWithPow2(ICmpInst *LHS,
707 ICmpInst *RHS,
708 Instruction *CxtI,
709 bool IsAnd,
710 bool IsLogical) {
712 if (LHS->getPredicate() != Pred || RHS->getPredicate() != Pred)
713 return nullptr;
714
715 if (!match(LHS->getOperand(1), m_Zero()) ||
716 !match(RHS->getOperand(1), m_Zero()))
717 return nullptr;
718
719 Value *L1, *L2, *R1, *R2;
720 if (match(LHS->getOperand(0), m_And(m_Value(L1), m_Value(L2))) &&
721 match(RHS->getOperand(0), m_And(m_Value(R1), m_Value(R2)))) {
722 if (L1 == R2 || L2 == R2)
723 std::swap(R1, R2);
724 if (L2 == R1)
725 std::swap(L1, L2);
726
727 if (L1 == R1 &&
728 isKnownToBeAPowerOfTwo(L2, false, 0, CxtI) &&
729 isKnownToBeAPowerOfTwo(R2, false, 0, CxtI)) {
730 // If this is a logical and/or, then we must prevent propagation of a
731 // poison value from the RHS by inserting freeze.
732 if (IsLogical)
734 Value *Mask = Builder.CreateOr(L2, R2);
735 Value *Masked = Builder.CreateAnd(L1, Mask);
736 auto NewPred = IsAnd ? CmpInst::ICMP_EQ : CmpInst::ICMP_NE;
737 return Builder.CreateICmp(NewPred, Masked, Mask);
738 }
739 }
740
741 return nullptr;
742}
743
744/// General pattern:
745/// X & Y
746///
747/// Where Y is checking that all the high bits (covered by a mask 4294967168)
748/// are uniform, i.e. %arg & 4294967168 can be either 4294967168 or 0
749/// Pattern can be one of:
750/// %t = add i32 %arg, 128
751/// %r = icmp ult i32 %t, 256
752/// Or
753/// %t0 = shl i32 %arg, 24
754/// %t1 = ashr i32 %t0, 24
755/// %r = icmp eq i32 %t1, %arg
756/// Or
757/// %t0 = trunc i32 %arg to i8
758/// %t1 = sext i8 %t0 to i32
759/// %r = icmp eq i32 %t1, %arg
760/// This pattern is a signed truncation check.
761///
762/// And X is checking that some bit in that same mask is zero.
763/// I.e. can be one of:
764/// %r = icmp sgt i32 %arg, -1
765/// Or
766/// %t = and i32 %arg, 2147483648
767/// %r = icmp eq i32 %t, 0
768///
769/// Since we are checking that all the bits in that mask are the same,
770/// and a particular bit is zero, what we are really checking is that all the
771/// masked bits are zero.
772/// So this should be transformed to:
773/// %r = icmp ult i32 %arg, 128
775 Instruction &CxtI,
776 InstCombiner::BuilderTy &Builder) {
777 assert(CxtI.getOpcode() == Instruction::And);
778
779 // Match icmp ult (add %arg, C01), C1 (C1 == C01 << 1; powers of two)
780 auto tryToMatchSignedTruncationCheck = [](ICmpInst *ICmp, Value *&X,
781 APInt &SignBitMask) -> bool {
783 const APInt *I01, *I1; // powers of two; I1 == I01 << 1
784 if (!(match(ICmp,
785 m_ICmp(Pred, m_Add(m_Value(X), m_Power2(I01)), m_Power2(I1))) &&
786 Pred == ICmpInst::ICMP_ULT && I1->ugt(*I01) && I01->shl(1) == *I1))
787 return false;
788 // Which bit is the new sign bit as per the 'signed truncation' pattern?
789 SignBitMask = *I01;
790 return true;
791 };
792
793 // One icmp needs to be 'signed truncation check'.
794 // We need to match this first, else we will mismatch commutative cases.
795 Value *X1;
796 APInt HighestBit;
797 ICmpInst *OtherICmp;
798 if (tryToMatchSignedTruncationCheck(ICmp1, X1, HighestBit))
799 OtherICmp = ICmp0;
800 else if (tryToMatchSignedTruncationCheck(ICmp0, X1, HighestBit))
801 OtherICmp = ICmp1;
802 else
803 return nullptr;
804
805 assert(HighestBit.isPowerOf2() && "expected to be power of two (non-zero)");
806
807 // Try to match/decompose into: icmp eq (X & Mask), 0
808 auto tryToDecompose = [](ICmpInst *ICmp, Value *&X,
809 APInt &UnsetBitsMask) -> bool {
810 CmpInst::Predicate Pred = ICmp->getPredicate();
811 // Can it be decomposed into icmp eq (X & Mask), 0 ?
812 if (llvm::decomposeBitTestICmp(ICmp->getOperand(0), ICmp->getOperand(1),
813 Pred, X, UnsetBitsMask,
814 /*LookThroughTrunc=*/false) &&
815 Pred == ICmpInst::ICMP_EQ)
816 return true;
817 // Is it icmp eq (X & Mask), 0 already?
818 const APInt *Mask;
819 if (match(ICmp, m_ICmp(Pred, m_And(m_Value(X), m_APInt(Mask)), m_Zero())) &&
820 Pred == ICmpInst::ICMP_EQ) {
821 UnsetBitsMask = *Mask;
822 return true;
823 }
824 return false;
825 };
826
827 // And the other icmp needs to be decomposable into a bit test.
828 Value *X0;
829 APInt UnsetBitsMask;
830 if (!tryToDecompose(OtherICmp, X0, UnsetBitsMask))
831 return nullptr;
832
833 assert(!UnsetBitsMask.isZero() && "empty mask makes no sense.");
834
835 // Are they working on the same value?
836 Value *X;
837 if (X1 == X0) {
838 // Ok as is.
839 X = X1;
840 } else if (match(X0, m_Trunc(m_Specific(X1)))) {
841 UnsetBitsMask = UnsetBitsMask.zext(X1->getType()->getScalarSizeInBits());
842 X = X1;
843 } else
844 return nullptr;
845
846 // So which bits should be uniform as per the 'signed truncation check'?
847 // (all the bits starting with (i.e. including) HighestBit)
848 APInt SignBitsMask = ~(HighestBit - 1U);
849
850 // UnsetBitsMask must have some common bits with SignBitsMask,
851 if (!UnsetBitsMask.intersects(SignBitsMask))
852 return nullptr;
853
854 // Does UnsetBitsMask contain any bits outside of SignBitsMask?
855 if (!UnsetBitsMask.isSubsetOf(SignBitsMask)) {
856 APInt OtherHighestBit = (~UnsetBitsMask) + 1U;
857 if (!OtherHighestBit.isPowerOf2())
858 return nullptr;
859 HighestBit = APIntOps::umin(HighestBit, OtherHighestBit);
860 }
861 // Else, if it does not, then all is ok as-is.
862
863 // %r = icmp ult %X, SignBit
864 return Builder.CreateICmpULT(X, ConstantInt::get(X->getType(), HighestBit),
865 CxtI.getName() + ".simplified");
866}
867
868/// Fold (icmp eq ctpop(X) 1) | (icmp eq X 0) into (icmp ult ctpop(X) 2) and
869/// fold (icmp ne ctpop(X) 1) & (icmp ne X 0) into (icmp ugt ctpop(X) 1).
870/// Also used for logical and/or, must be poison safe.
871static Value *foldIsPowerOf2OrZero(ICmpInst *Cmp0, ICmpInst *Cmp1, bool IsAnd,
872 InstCombiner::BuilderTy &Builder) {
873 CmpInst::Predicate Pred0, Pred1;
874 Value *X;
875 if (!match(Cmp0, m_ICmp(Pred0, m_Intrinsic<Intrinsic::ctpop>(m_Value(X)),
876 m_SpecificInt(1))) ||
877 !match(Cmp1, m_ICmp(Pred1, m_Specific(X), m_ZeroInt())))
878 return nullptr;
879
880 Value *CtPop = Cmp0->getOperand(0);
881 if (IsAnd && Pred0 == ICmpInst::ICMP_NE && Pred1 == ICmpInst::ICMP_NE)
882 return Builder.CreateICmpUGT(CtPop, ConstantInt::get(CtPop->getType(), 1));
883 if (!IsAnd && Pred0 == ICmpInst::ICMP_EQ && Pred1 == ICmpInst::ICMP_EQ)
884 return Builder.CreateICmpULT(CtPop, ConstantInt::get(CtPop->getType(), 2));
885
886 return nullptr;
887}
888
889/// Reduce a pair of compares that check if a value has exactly 1 bit set.
890/// Also used for logical and/or, must be poison safe.
891static Value *foldIsPowerOf2(ICmpInst *Cmp0, ICmpInst *Cmp1, bool JoinedByAnd,
892 InstCombiner::BuilderTy &Builder) {
893 // Handle 'and' / 'or' commutation: make the equality check the first operand.
894 if (JoinedByAnd && Cmp1->getPredicate() == ICmpInst::ICMP_NE)
895 std::swap(Cmp0, Cmp1);
896 else if (!JoinedByAnd && Cmp1->getPredicate() == ICmpInst::ICMP_EQ)
897 std::swap(Cmp0, Cmp1);
898
899 // (X != 0) && (ctpop(X) u< 2) --> ctpop(X) == 1
900 CmpInst::Predicate Pred0, Pred1;
901 Value *X;
902 if (JoinedByAnd && match(Cmp0, m_ICmp(Pred0, m_Value(X), m_ZeroInt())) &&
903 match(Cmp1, m_ICmp(Pred1, m_Intrinsic<Intrinsic::ctpop>(m_Specific(X)),
904 m_SpecificInt(2))) &&
905 Pred0 == ICmpInst::ICMP_NE && Pred1 == ICmpInst::ICMP_ULT) {
906 Value *CtPop = Cmp1->getOperand(0);
907 return Builder.CreateICmpEQ(CtPop, ConstantInt::get(CtPop->getType(), 1));
908 }
909 // (X == 0) || (ctpop(X) u> 1) --> ctpop(X) != 1
910 if (!JoinedByAnd && match(Cmp0, m_ICmp(Pred0, m_Value(X), m_ZeroInt())) &&
911 match(Cmp1, m_ICmp(Pred1, m_Intrinsic<Intrinsic::ctpop>(m_Specific(X)),
912 m_SpecificInt(1))) &&
913 Pred0 == ICmpInst::ICMP_EQ && Pred1 == ICmpInst::ICMP_UGT) {
914 Value *CtPop = Cmp1->getOperand(0);
915 return Builder.CreateICmpNE(CtPop, ConstantInt::get(CtPop->getType(), 1));
916 }
917 return nullptr;
918}
919
920/// Try to fold (icmp(A & B) == 0) & (icmp(A & D) != E) into (icmp A u< D) iff
921/// B is a contiguous set of ones starting from the most significant bit
922/// (negative power of 2), D and E are equal, and D is a contiguous set of ones
923/// starting at the most significant zero bit in B. Parameter B supports masking
924/// using undef/poison in either scalar or vector values.
926 Value *A, Value *B, Value *D, Value *E, ICmpInst::Predicate PredL,
929 "Expected equality predicates for masked type of icmps.");
930 if (PredL != ICmpInst::ICMP_EQ || PredR != ICmpInst::ICMP_NE)
931 return nullptr;
932
933 if (!match(B, m_NegatedPower2()) || !match(D, m_ShiftedMask()) ||
934 !match(E, m_ShiftedMask()))
935 return nullptr;
936
937 // Test scalar arguments for conversion. B has been validated earlier to be a
938 // negative power of two and thus is guaranteed to have one or more contiguous
939 // ones starting from the MSB followed by zero or more contiguous zeros. D has
940 // been validated earlier to be a shifted set of one or more contiguous ones.
941 // In order to match, B leading ones and D leading zeros should be equal. The
942 // predicate that B be a negative power of 2 prevents the condition of there
943 // ever being zero leading ones. Thus 0 == 0 cannot occur. The predicate that
944 // D always be a shifted mask prevents the condition of D equaling 0. This
945 // prevents matching the condition where B contains the maximum number of
946 // leading one bits (-1) and D contains the maximum number of leading zero
947 // bits (0).
948 auto isReducible = [](const Value *B, const Value *D, const Value *E) {
949 const APInt *BCst, *DCst, *ECst;
950 return match(B, m_APIntAllowPoison(BCst)) && match(D, m_APInt(DCst)) &&
951 match(E, m_APInt(ECst)) && *DCst == *ECst &&
952 (isa<PoisonValue>(B) ||
953 (BCst->countLeadingOnes() == DCst->countLeadingZeros()));
954 };
955
956 // Test vector type arguments for conversion.
957 if (const auto *BVTy = dyn_cast<VectorType>(B->getType())) {
958 const auto *BFVTy = dyn_cast<FixedVectorType>(BVTy);
959 const auto *BConst = dyn_cast<Constant>(B);
960 const auto *DConst = dyn_cast<Constant>(D);
961 const auto *EConst = dyn_cast<Constant>(E);
962
963 if (!BFVTy || !BConst || !DConst || !EConst)
964 return nullptr;
965
966 for (unsigned I = 0; I != BFVTy->getNumElements(); ++I) {
967 const auto *BElt = BConst->getAggregateElement(I);
968 const auto *DElt = DConst->getAggregateElement(I);
969 const auto *EElt = EConst->getAggregateElement(I);
970
971 if (!BElt || !DElt || !EElt)
972 return nullptr;
973 if (!isReducible(BElt, DElt, EElt))
974 return nullptr;
975 }
976 } else {
977 // Test scalar type arguments for conversion.
978 if (!isReducible(B, D, E))
979 return nullptr;
980 }
981 return Builder.CreateICmp(ICmpInst::ICMP_ULT, A, D);
982}
983
984/// Try to fold ((icmp X u< P) & (icmp(X & M) != M)) or ((icmp X s> -1) &
985/// (icmp(X & M) != M)) into (icmp X u< M). Where P is a power of 2, M < P, and
986/// M is a contiguous shifted mask starting at the right most significant zero
987/// bit in P. SGT is supported as when P is the largest representable power of
988/// 2, an earlier optimization converts the expression into (icmp X s> -1).
989/// Parameter P supports masking using undef/poison in either scalar or vector
990/// values.
992 bool JoinedByAnd,
993 InstCombiner::BuilderTy &Builder) {
994 if (!JoinedByAnd)
995 return nullptr;
996 Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr, *E = nullptr;
997 ICmpInst::Predicate CmpPred0 = Cmp0->getPredicate(),
998 CmpPred1 = Cmp1->getPredicate();
999 // Assuming P is a 2^n, getMaskedTypeForICmpPair will normalize (icmp X u<
1000 // 2^n) into (icmp (X & ~(2^n-1)) == 0) and (icmp X s> -1) into (icmp (X &
1001 // SignMask) == 0).
1002 std::optional<std::pair<unsigned, unsigned>> MaskPair =
1003 getMaskedTypeForICmpPair(A, B, C, D, E, Cmp0, Cmp1, CmpPred0, CmpPred1);
1004 if (!MaskPair)
1005 return nullptr;
1006
1007 const auto compareBMask = BMask_NotMixed | BMask_NotAllOnes;
1008 unsigned CmpMask0 = MaskPair->first;
1009 unsigned CmpMask1 = MaskPair->second;
1010 if ((CmpMask0 & Mask_AllZeros) && (CmpMask1 == compareBMask)) {
1011 if (Value *V = foldNegativePower2AndShiftedMask(A, B, D, E, CmpPred0,
1012 CmpPred1, Builder))
1013 return V;
1014 } else if ((CmpMask0 == compareBMask) && (CmpMask1 & Mask_AllZeros)) {
1015 if (Value *V = foldNegativePower2AndShiftedMask(A, D, B, C, CmpPred1,
1016 CmpPred0, Builder))
1017 return V;
1018 }
1019 return nullptr;
1020}
1021
1022/// Commuted variants are assumed to be handled by calling this function again
1023/// with the parameters swapped.
1025 ICmpInst *UnsignedICmp, bool IsAnd,
1026 const SimplifyQuery &Q,
1027 InstCombiner::BuilderTy &Builder) {
1028 Value *ZeroCmpOp;
1029 ICmpInst::Predicate EqPred;
1030 if (!match(ZeroICmp, m_ICmp(EqPred, m_Value(ZeroCmpOp), m_Zero())) ||
1031 !ICmpInst::isEquality(EqPred))
1032 return nullptr;
1033
1034 ICmpInst::Predicate UnsignedPred;
1035
1036 Value *A, *B;
1037 if (match(UnsignedICmp,
1038 m_c_ICmp(UnsignedPred, m_Specific(ZeroCmpOp), m_Value(A))) &&
1039 match(ZeroCmpOp, m_c_Add(m_Specific(A), m_Value(B))) &&
1040 (ZeroICmp->hasOneUse() || UnsignedICmp->hasOneUse())) {
1041 auto GetKnownNonZeroAndOther = [&](Value *&NonZero, Value *&Other) {
1042 if (!isKnownNonZero(NonZero, Q))
1043 std::swap(NonZero, Other);
1044 return isKnownNonZero(NonZero, Q);
1045 };
1046
1047 // Given ZeroCmpOp = (A + B)
1048 // ZeroCmpOp < A && ZeroCmpOp != 0 --> (0-X) < Y iff
1049 // ZeroCmpOp >= A || ZeroCmpOp == 0 --> (0-X) >= Y iff
1050 // with X being the value (A/B) that is known to be non-zero,
1051 // and Y being remaining value.
1052 if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_NE &&
1053 IsAnd && GetKnownNonZeroAndOther(B, A))
1054 return Builder.CreateICmpULT(Builder.CreateNeg(B), A);
1055 if (UnsignedPred == ICmpInst::ICMP_UGE && EqPred == ICmpInst::ICMP_EQ &&
1056 !IsAnd && GetKnownNonZeroAndOther(B, A))
1057 return Builder.CreateICmpUGE(Builder.CreateNeg(B), A);
1058 }
1059
1060 return nullptr;
1061}
1062
1063struct IntPart {
1065 unsigned StartBit;
1066 unsigned NumBits;
1067};
1068
1069/// Match an extraction of bits from an integer.
1070static std::optional<IntPart> matchIntPart(Value *V) {
1071 Value *X;
1072 if (!match(V, m_OneUse(m_Trunc(m_Value(X)))))
1073 return std::nullopt;
1074
1075 unsigned NumOriginalBits = X->getType()->getScalarSizeInBits();
1076 unsigned NumExtractedBits = V->getType()->getScalarSizeInBits();
1077 Value *Y;
1078 const APInt *Shift;
1079 // For a trunc(lshr Y, Shift) pattern, make sure we're only extracting bits
1080 // from Y, not any shifted-in zeroes.
1081 if (match(X, m_OneUse(m_LShr(m_Value(Y), m_APInt(Shift)))) &&
1082 Shift->ule(NumOriginalBits - NumExtractedBits))
1083 return {{Y, (unsigned)Shift->getZExtValue(), NumExtractedBits}};
1084 return {{X, 0, NumExtractedBits}};
1085}
1086
1087/// Materialize an extraction of bits from an integer in IR.
1088static Value *extractIntPart(const IntPart &P, IRBuilderBase &Builder) {
1089 Value *V = P.From;
1090 if (P.StartBit)
1091 V = Builder.CreateLShr(V, P.StartBit);
1092 Type *TruncTy = V->getType()->getWithNewBitWidth(P.NumBits);
1093 if (TruncTy != V->getType())
1094 V = Builder.CreateTrunc(V, TruncTy);
1095 return V;
1096}
1097
1098/// (icmp eq X0, Y0) & (icmp eq X1, Y1) -> icmp eq X01, Y01
1099/// (icmp ne X0, Y0) | (icmp ne X1, Y1) -> icmp ne X01, Y01
1100/// where X0, X1 and Y0, Y1 are adjacent parts extracted from an integer.
1101Value *InstCombinerImpl::foldEqOfParts(ICmpInst *Cmp0, ICmpInst *Cmp1,
1102 bool IsAnd) {
1103 if (!Cmp0->hasOneUse() || !Cmp1->hasOneUse())
1104 return nullptr;
1105
1107 auto GetMatchPart = [&](ICmpInst *Cmp,
1108 unsigned OpNo) -> std::optional<IntPart> {
1109 if (Pred == Cmp->getPredicate())
1110 return matchIntPart(Cmp->getOperand(OpNo));
1111
1112 const APInt *C;
1113 // (icmp eq (lshr x, C), (lshr y, C)) gets optimized to:
1114 // (icmp ult (xor x, y), 1 << C) so also look for that.
1115 if (Pred == CmpInst::ICMP_EQ && Cmp->getPredicate() == CmpInst::ICMP_ULT) {
1116 if (!match(Cmp->getOperand(1), m_Power2(C)) ||
1117 !match(Cmp->getOperand(0), m_Xor(m_Value(), m_Value())))
1118 return std::nullopt;
1119 }
1120
1121 // (icmp ne (lshr x, C), (lshr y, C)) gets optimized to:
1122 // (icmp ugt (xor x, y), (1 << C) - 1) so also look for that.
1123 else if (Pred == CmpInst::ICMP_NE &&
1124 Cmp->getPredicate() == CmpInst::ICMP_UGT) {
1125 if (!match(Cmp->getOperand(1), m_LowBitMask(C)) ||
1126 !match(Cmp->getOperand(0), m_Xor(m_Value(), m_Value())))
1127 return std::nullopt;
1128 } else {
1129 return std::nullopt;
1130 }
1131
1132 unsigned From = Pred == CmpInst::ICMP_NE ? C->popcount() : C->countr_zero();
1133 Instruction *I = cast<Instruction>(Cmp->getOperand(0));
1134 return {{I->getOperand(OpNo), From, C->getBitWidth() - From}};
1135 };
1136
1137 std::optional<IntPart> L0 = GetMatchPart(Cmp0, 0);
1138 std::optional<IntPart> R0 = GetMatchPart(Cmp0, 1);
1139 std::optional<IntPart> L1 = GetMatchPart(Cmp1, 0);
1140 std::optional<IntPart> R1 = GetMatchPart(Cmp1, 1);
1141 if (!L0 || !R0 || !L1 || !R1)
1142 return nullptr;
1143
1144 // Make sure the LHS/RHS compare a part of the same value, possibly after
1145 // an operand swap.
1146 if (L0->From != L1->From || R0->From != R1->From) {
1147 if (L0->From != R1->From || R0->From != L1->From)
1148 return nullptr;
1149 std::swap(L1, R1);
1150 }
1151
1152 // Make sure the extracted parts are adjacent, canonicalizing to L0/R0 being
1153 // the low part and L1/R1 being the high part.
1154 if (L0->StartBit + L0->NumBits != L1->StartBit ||
1155 R0->StartBit + R0->NumBits != R1->StartBit) {
1156 if (L1->StartBit + L1->NumBits != L0->StartBit ||
1157 R1->StartBit + R1->NumBits != R0->StartBit)
1158 return nullptr;
1159 std::swap(L0, L1);
1160 std::swap(R0, R1);
1161 }
1162
1163 // We can simplify to a comparison of these larger parts of the integers.
1164 IntPart L = {L0->From, L0->StartBit, L0->NumBits + L1->NumBits};
1165 IntPart R = {R0->From, R0->StartBit, R0->NumBits + R1->NumBits};
1168 return Builder.CreateICmp(Pred, LValue, RValue);
1169}
1170
1171/// Reduce logic-of-compares with equality to a constant by substituting a
1172/// common operand with the constant. Callers are expected to call this with
1173/// Cmp0/Cmp1 switched to handle logic op commutativity.
1175 bool IsAnd, bool IsLogical,
1176 InstCombiner::BuilderTy &Builder,
1177 const SimplifyQuery &Q) {
1178 // Match an equality compare with a non-poison constant as Cmp0.
1179 // Also, give up if the compare can be constant-folded to avoid looping.
1180 ICmpInst::Predicate Pred0;
1181 Value *X;
1182 Constant *C;
1183 if (!match(Cmp0, m_ICmp(Pred0, m_Value(X), m_Constant(C))) ||
1184 !isGuaranteedNotToBeUndefOrPoison(C) || isa<Constant>(X))
1185 return nullptr;
1186 if ((IsAnd && Pred0 != ICmpInst::ICMP_EQ) ||
1187 (!IsAnd && Pred0 != ICmpInst::ICMP_NE))
1188 return nullptr;
1189
1190 // The other compare must include a common operand (X). Canonicalize the
1191 // common operand as operand 1 (Pred1 is swapped if the common operand was
1192 // operand 0).
1193 Value *Y;
1194 ICmpInst::Predicate Pred1;
1195 if (!match(Cmp1, m_c_ICmp(Pred1, m_Value(Y), m_Deferred(X))))
1196 return nullptr;
1197
1198 // Replace variable with constant value equivalence to remove a variable use:
1199 // (X == C) && (Y Pred1 X) --> (X == C) && (Y Pred1 C)
1200 // (X != C) || (Y Pred1 X) --> (X != C) || (Y Pred1 C)
1201 // Can think of the 'or' substitution with the 'and' bool equivalent:
1202 // A || B --> A || (!A && B)
1203 Value *SubstituteCmp = simplifyICmpInst(Pred1, Y, C, Q);
1204 if (!SubstituteCmp) {
1205 // If we need to create a new instruction, require that the old compare can
1206 // be removed.
1207 if (!Cmp1->hasOneUse())
1208 return nullptr;
1209 SubstituteCmp = Builder.CreateICmp(Pred1, Y, C);
1210 }
1211 if (IsLogical)
1212 return IsAnd ? Builder.CreateLogicalAnd(Cmp0, SubstituteCmp)
1213 : Builder.CreateLogicalOr(Cmp0, SubstituteCmp);
1214 return Builder.CreateBinOp(IsAnd ? Instruction::And : Instruction::Or, Cmp0,
1215 SubstituteCmp);
1216}
1217
1218/// Fold (icmp Pred1 V1, C1) & (icmp Pred2 V2, C2)
1219/// or (icmp Pred1 V1, C1) | (icmp Pred2 V2, C2)
1220/// into a single comparison using range-based reasoning.
1221/// NOTE: This is also used for logical and/or, must be poison-safe!
1222Value *InstCombinerImpl::foldAndOrOfICmpsUsingRanges(ICmpInst *ICmp1,
1223 ICmpInst *ICmp2,
1224 bool IsAnd) {
1225 ICmpInst::Predicate Pred1, Pred2;
1226 Value *V1, *V2;
1227 const APInt *C1, *C2;
1228 if (!match(ICmp1, m_ICmp(Pred1, m_Value(V1), m_APInt(C1))) ||
1229 !match(ICmp2, m_ICmp(Pred2, m_Value(V2), m_APInt(C2))))
1230 return nullptr;
1231
1232 // Look through add of a constant offset on V1, V2, or both operands. This
1233 // allows us to interpret the V + C' < C'' range idiom into a proper range.
1234 const APInt *Offset1 = nullptr, *Offset2 = nullptr;
1235 if (V1 != V2) {
1236 Value *X;
1237 if (match(V1, m_Add(m_Value(X), m_APInt(Offset1))))
1238 V1 = X;
1239 if (match(V2, m_Add(m_Value(X), m_APInt(Offset2))))
1240 V2 = X;
1241 }
1242
1243 if (V1 != V2)
1244 return nullptr;
1245
1247 IsAnd ? ICmpInst::getInversePredicate(Pred1) : Pred1, *C1);
1248 if (Offset1)
1249 CR1 = CR1.subtract(*Offset1);
1250
1252 IsAnd ? ICmpInst::getInversePredicate(Pred2) : Pred2, *C2);
1253 if (Offset2)
1254 CR2 = CR2.subtract(*Offset2);
1255
1256 Type *Ty = V1->getType();
1257 Value *NewV = V1;
1258 std::optional<ConstantRange> CR = CR1.exactUnionWith(CR2);
1259 if (!CR) {
1260 if (!(ICmp1->hasOneUse() && ICmp2->hasOneUse()) || CR1.isWrappedSet() ||
1261 CR2.isWrappedSet())
1262 return nullptr;
1263
1264 // Check whether we have equal-size ranges that only differ by one bit.
1265 // In that case we can apply a mask to map one range onto the other.
1266 APInt LowerDiff = CR1.getLower() ^ CR2.getLower();
1267 APInt UpperDiff = (CR1.getUpper() - 1) ^ (CR2.getUpper() - 1);
1268 APInt CR1Size = CR1.getUpper() - CR1.getLower();
1269 if (!LowerDiff.isPowerOf2() || LowerDiff != UpperDiff ||
1270 CR1Size != CR2.getUpper() - CR2.getLower())
1271 return nullptr;
1272
1273 CR = CR1.getLower().ult(CR2.getLower()) ? CR1 : CR2;
1274 NewV = Builder.CreateAnd(NewV, ConstantInt::get(Ty, ~LowerDiff));
1275 }
1276
1277 if (IsAnd)
1278 CR = CR->inverse();
1279
1280 CmpInst::Predicate NewPred;
1281 APInt NewC, Offset;
1282 CR->getEquivalentICmp(NewPred, NewC, Offset);
1283
1284 if (Offset != 0)
1285 NewV = Builder.CreateAdd(NewV, ConstantInt::get(Ty, Offset));
1286 return Builder.CreateICmp(NewPred, NewV, ConstantInt::get(Ty, NewC));
1287}
1288
1289/// Ignore all operations which only change the sign of a value, returning the
1290/// underlying magnitude value.
1292 match(Val, m_FNeg(m_Value(Val)));
1293 match(Val, m_FAbs(m_Value(Val)));
1294 match(Val, m_CopySign(m_Value(Val), m_Value()));
1295 return Val;
1296}
1297
1298/// Matches canonical form of isnan, fcmp ord x, 0
1300 return P == FCmpInst::FCMP_ORD && match(RHS, m_AnyZeroFP());
1301}
1302
1303/// Matches fcmp u__ x, +/-inf
1305 Value *RHS) {
1306 return FCmpInst::isUnordered(P) && match(RHS, m_Inf());
1307}
1308
1309/// and (fcmp ord x, 0), (fcmp u* x, inf) -> fcmp o* x, inf
1310///
1311/// Clang emits this pattern for doing an isfinite check in __builtin_isnormal.
1313 FCmpInst *RHS) {
1314 Value *LHS0 = LHS->getOperand(0), *LHS1 = LHS->getOperand(1);
1315 Value *RHS0 = RHS->getOperand(0), *RHS1 = RHS->getOperand(1);
1316 FCmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
1317
1318 if (!matchIsNotNaN(PredL, LHS0, LHS1) ||
1319 !matchUnorderedInfCompare(PredR, RHS0, RHS1))
1320 return nullptr;
1321
1322 IRBuilder<>::FastMathFlagGuard FMFG(Builder);
1323 FastMathFlags FMF = LHS->getFastMathFlags();
1324 FMF &= RHS->getFastMathFlags();
1325 Builder.setFastMathFlags(FMF);
1326
1327 return Builder.CreateFCmp(FCmpInst::getOrderedPredicate(PredR), RHS0, RHS1);
1328}
1329
1330Value *InstCombinerImpl::foldLogicOfFCmps(FCmpInst *LHS, FCmpInst *RHS,
1331 bool IsAnd, bool IsLogicalSelect) {
1332 Value *LHS0 = LHS->getOperand(0), *LHS1 = LHS->getOperand(1);
1333 Value *RHS0 = RHS->getOperand(0), *RHS1 = RHS->getOperand(1);
1334 FCmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
1335
1336 if (LHS0 == RHS1 && RHS0 == LHS1) {
1337 // Swap RHS operands to match LHS.
1338 PredR = FCmpInst::getSwappedPredicate(PredR);
1339 std::swap(RHS0, RHS1);
1340 }
1341
1342 // Simplify (fcmp cc0 x, y) & (fcmp cc1 x, y).
1343 // Suppose the relation between x and y is R, where R is one of
1344 // U(1000), L(0100), G(0010) or E(0001), and CC0 and CC1 are the bitmasks for
1345 // testing the desired relations.
1346 //
1347 // Since (R & CC0) and (R & CC1) are either R or 0, we actually have this:
1348 // bool(R & CC0) && bool(R & CC1)
1349 // = bool((R & CC0) & (R & CC1))
1350 // = bool(R & (CC0 & CC1)) <= by re-association, commutation, and idempotency
1351 //
1352 // Since (R & CC0) and (R & CC1) are either R or 0, we actually have this:
1353 // bool(R & CC0) || bool(R & CC1)
1354 // = bool((R & CC0) | (R & CC1))
1355 // = bool(R & (CC0 | CC1)) <= by reversed distribution (contribution? ;)
1356 if (LHS0 == RHS0 && LHS1 == RHS1) {
1357 unsigned FCmpCodeL = getFCmpCode(PredL);
1358 unsigned FCmpCodeR = getFCmpCode(PredR);
1359 unsigned NewPred = IsAnd ? FCmpCodeL & FCmpCodeR : FCmpCodeL | FCmpCodeR;
1360
1361 // Intersect the fast math flags.
1362 // TODO: We can union the fast math flags unless this is a logical select.
1364 FastMathFlags FMF = LHS->getFastMathFlags();
1365 FMF &= RHS->getFastMathFlags();
1367
1368 return getFCmpValue(NewPred, LHS0, LHS1, Builder);
1369 }
1370
1371 // This transform is not valid for a logical select.
1372 if (!IsLogicalSelect &&
1373 ((PredL == FCmpInst::FCMP_ORD && PredR == FCmpInst::FCMP_ORD && IsAnd) ||
1374 (PredL == FCmpInst::FCMP_UNO && PredR == FCmpInst::FCMP_UNO &&
1375 !IsAnd))) {
1376 if (LHS0->getType() != RHS0->getType())
1377 return nullptr;
1378
1379 // FCmp canonicalization ensures that (fcmp ord/uno X, X) and
1380 // (fcmp ord/uno X, C) will be transformed to (fcmp X, +0.0).
1381 if (match(LHS1, m_PosZeroFP()) && match(RHS1, m_PosZeroFP()))
1382 // Ignore the constants because they are obviously not NANs:
1383 // (fcmp ord x, 0.0) & (fcmp ord y, 0.0) -> (fcmp ord x, y)
1384 // (fcmp uno x, 0.0) | (fcmp uno y, 0.0) -> (fcmp uno x, y)
1385 return Builder.CreateFCmp(PredL, LHS0, RHS0);
1386 }
1387
1388 if (IsAnd && stripSignOnlyFPOps(LHS0) == stripSignOnlyFPOps(RHS0)) {
1389 // and (fcmp ord x, 0), (fcmp u* x, inf) -> fcmp o* x, inf
1390 // and (fcmp ord x, 0), (fcmp u* fabs(x), inf) -> fcmp o* x, inf
1391 if (Value *Left = matchIsFiniteTest(Builder, LHS, RHS))
1392 return Left;
1393 if (Value *Right = matchIsFiniteTest(Builder, RHS, LHS))
1394 return Right;
1395 }
1396
1397 // Turn at least two fcmps with constants into llvm.is.fpclass.
1398 //
1399 // If we can represent a combined value test with one class call, we can
1400 // potentially eliminate 4-6 instructions. If we can represent a test with a
1401 // single fcmp with fneg and fabs, that's likely a better canonical form.
1402 if (LHS->hasOneUse() && RHS->hasOneUse()) {
1403 auto [ClassValRHS, ClassMaskRHS] =
1404 fcmpToClassTest(PredR, *RHS->getFunction(), RHS0, RHS1);
1405 if (ClassValRHS) {
1406 auto [ClassValLHS, ClassMaskLHS] =
1407 fcmpToClassTest(PredL, *LHS->getFunction(), LHS0, LHS1);
1408 if (ClassValLHS == ClassValRHS) {
1409 unsigned CombinedMask = IsAnd ? (ClassMaskLHS & ClassMaskRHS)
1410 : (ClassMaskLHS | ClassMaskRHS);
1411 return Builder.CreateIntrinsic(
1412 Intrinsic::is_fpclass, {ClassValLHS->getType()},
1413 {ClassValLHS, Builder.getInt32(CombinedMask)});
1414 }
1415 }
1416 }
1417
1418 // Canonicalize the range check idiom:
1419 // and (fcmp olt/ole/ult/ule x, C), (fcmp ogt/oge/ugt/uge x, -C)
1420 // --> fabs(x) olt/ole/ult/ule C
1421 // or (fcmp ogt/oge/ugt/uge x, C), (fcmp olt/ole/ult/ule x, -C)
1422 // --> fabs(x) ogt/oge/ugt/uge C
1423 // TODO: Generalize to handle a negated variable operand?
1424 const APFloat *LHSC, *RHSC;
1425 if (LHS0 == RHS0 && LHS->hasOneUse() && RHS->hasOneUse() &&
1426 FCmpInst::getSwappedPredicate(PredL) == PredR &&
1427 match(LHS1, m_APFloatAllowPoison(LHSC)) &&
1428 match(RHS1, m_APFloatAllowPoison(RHSC)) &&
1429 LHSC->bitwiseIsEqual(neg(*RHSC))) {
1430 auto IsLessThanOrLessEqual = [](FCmpInst::Predicate Pred) {
1431 switch (Pred) {
1432 case FCmpInst::FCMP_OLT:
1433 case FCmpInst::FCMP_OLE:
1434 case FCmpInst::FCMP_ULT:
1435 case FCmpInst::FCMP_ULE:
1436 return true;
1437 default:
1438 return false;
1439 }
1440 };
1441 if (IsLessThanOrLessEqual(IsAnd ? PredR : PredL)) {
1442 std::swap(LHSC, RHSC);
1443 std::swap(PredL, PredR);
1444 }
1445 if (IsLessThanOrLessEqual(IsAnd ? PredL : PredR)) {
1447 Builder.setFastMathFlags(LHS->getFastMathFlags() |
1448 RHS->getFastMathFlags());
1449
1450 Value *FAbs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, LHS0);
1451 return Builder.CreateFCmp(PredL, FAbs,
1452 ConstantFP::get(LHS0->getType(), *LHSC));
1453 }
1454 }
1455
1456 return nullptr;
1457}
1458
1459/// Match an fcmp against a special value that performs a test possible by
1460/// llvm.is.fpclass.
1461static bool matchIsFPClassLikeFCmp(Value *Op, Value *&ClassVal,
1462 uint64_t &ClassMask) {
1463 auto *FCmp = dyn_cast<FCmpInst>(Op);
1464 if (!FCmp || !FCmp->hasOneUse())
1465 return false;
1466
1467 std::tie(ClassVal, ClassMask) =
1468 fcmpToClassTest(FCmp->getPredicate(), *FCmp->getParent()->getParent(),
1469 FCmp->getOperand(0), FCmp->getOperand(1));
1470 return ClassVal != nullptr;
1471}
1472
1473/// or (is_fpclass x, mask0), (is_fpclass x, mask1)
1474/// -> is_fpclass x, (mask0 | mask1)
1475/// and (is_fpclass x, mask0), (is_fpclass x, mask1)
1476/// -> is_fpclass x, (mask0 & mask1)
1477/// xor (is_fpclass x, mask0), (is_fpclass x, mask1)
1478/// -> is_fpclass x, (mask0 ^ mask1)
1479Instruction *InstCombinerImpl::foldLogicOfIsFPClass(BinaryOperator &BO,
1480 Value *Op0, Value *Op1) {
1481 Value *ClassVal0 = nullptr;
1482 Value *ClassVal1 = nullptr;
1483 uint64_t ClassMask0, ClassMask1;
1484
1485 // Restrict to folding one fcmp into one is.fpclass for now, don't introduce a
1486 // new class.
1487 //
1488 // TODO: Support forming is.fpclass out of 2 separate fcmps when codegen is
1489 // better.
1490
1491 bool IsLHSClass =
1492 match(Op0, m_OneUse(m_Intrinsic<Intrinsic::is_fpclass>(
1493 m_Value(ClassVal0), m_ConstantInt(ClassMask0))));
1494 bool IsRHSClass =
1495 match(Op1, m_OneUse(m_Intrinsic<Intrinsic::is_fpclass>(
1496 m_Value(ClassVal1), m_ConstantInt(ClassMask1))));
1497 if ((((IsLHSClass || matchIsFPClassLikeFCmp(Op0, ClassVal0, ClassMask0)) &&
1498 (IsRHSClass || matchIsFPClassLikeFCmp(Op1, ClassVal1, ClassMask1)))) &&
1499 ClassVal0 == ClassVal1) {
1500 unsigned NewClassMask;
1501 switch (BO.getOpcode()) {
1502 case Instruction::And:
1503 NewClassMask = ClassMask0 & ClassMask1;
1504 break;
1505 case Instruction::Or:
1506 NewClassMask = ClassMask0 | ClassMask1;
1507 break;
1508 case Instruction::Xor:
1509 NewClassMask = ClassMask0 ^ ClassMask1;
1510 break;
1511 default:
1512 llvm_unreachable("not a binary logic operator");
1513 }
1514
1515 if (IsLHSClass) {
1516 auto *II = cast<IntrinsicInst>(Op0);
1517 II->setArgOperand(
1518 1, ConstantInt::get(II->getArgOperand(1)->getType(), NewClassMask));
1519 return replaceInstUsesWith(BO, II);
1520 }
1521
1522 if (IsRHSClass) {
1523 auto *II = cast<IntrinsicInst>(Op1);
1524 II->setArgOperand(
1525 1, ConstantInt::get(II->getArgOperand(1)->getType(), NewClassMask));
1526 return replaceInstUsesWith(BO, II);
1527 }
1528
1529 CallInst *NewClass =
1530 Builder.CreateIntrinsic(Intrinsic::is_fpclass, {ClassVal0->getType()},
1531 {ClassVal0, Builder.getInt32(NewClassMask)});
1532 return replaceInstUsesWith(BO, NewClass);
1533 }
1534
1535 return nullptr;
1536}
1537
1538/// Look for the pattern that conditionally negates a value via math operations:
1539/// cond.splat = sext i1 cond
1540/// sub = add cond.splat, x
1541/// xor = xor sub, cond.splat
1542/// and rewrite it to do the same, but via logical operations:
1543/// value.neg = sub 0, value
1544/// cond = select i1 neg, value.neg, value
1545Instruction *InstCombinerImpl::canonicalizeConditionalNegationViaMathToSelect(
1546 BinaryOperator &I) {
1547 assert(I.getOpcode() == BinaryOperator::Xor && "Only for xor!");
1548 Value *Cond, *X;
1549 // As per complexity ordering, `xor` is not commutative here.
1550 if (!match(&I, m_c_BinOp(m_OneUse(m_Value()), m_Value())) ||
1551 !match(I.getOperand(1), m_SExt(m_Value(Cond))) ||
1552 !Cond->getType()->isIntOrIntVectorTy(1) ||
1553 !match(I.getOperand(0), m_c_Add(m_SExt(m_Deferred(Cond)), m_Value(X))))
1554 return nullptr;
1555 return SelectInst::Create(Cond, Builder.CreateNeg(X, X->getName() + ".neg"),
1556 X);
1557}
1558
1559/// This a limited reassociation for a special case (see above) where we are
1560/// checking if two values are either both NAN (unordered) or not-NAN (ordered).
1561/// This could be handled more generally in '-reassociation', but it seems like
1562/// an unlikely pattern for a large number of logic ops and fcmps.
1564 InstCombiner::BuilderTy &Builder) {
1565 Instruction::BinaryOps Opcode = BO.getOpcode();
1566 assert((Opcode == Instruction::And || Opcode == Instruction::Or) &&
1567 "Expecting and/or op for fcmp transform");
1568
1569 // There are 4 commuted variants of the pattern. Canonicalize operands of this
1570 // logic op so an fcmp is operand 0 and a matching logic op is operand 1.
1571 Value *Op0 = BO.getOperand(0), *Op1 = BO.getOperand(1), *X;
1573 if (match(Op1, m_FCmp(Pred, m_Value(), m_AnyZeroFP())))
1574 std::swap(Op0, Op1);
1575
1576 // Match inner binop and the predicate for combining 2 NAN checks into 1.
1577 Value *BO10, *BO11;
1578 FCmpInst::Predicate NanPred = Opcode == Instruction::And ? FCmpInst::FCMP_ORD
1580 if (!match(Op0, m_FCmp(Pred, m_Value(X), m_AnyZeroFP())) || Pred != NanPred ||
1581 !match(Op1, m_BinOp(Opcode, m_Value(BO10), m_Value(BO11))))
1582 return nullptr;
1583
1584 // The inner logic op must have a matching fcmp operand.
1585 Value *Y;
1586 if (!match(BO10, m_FCmp(Pred, m_Value(Y), m_AnyZeroFP())) ||
1587 Pred != NanPred || X->getType() != Y->getType())
1588 std::swap(BO10, BO11);
1589
1590 if (!match(BO10, m_FCmp(Pred, m_Value(Y), m_AnyZeroFP())) ||
1591 Pred != NanPred || X->getType() != Y->getType())
1592 return nullptr;
1593
1594 // and (fcmp ord X, 0), (and (fcmp ord Y, 0), Z) --> and (fcmp ord X, Y), Z
1595 // or (fcmp uno X, 0), (or (fcmp uno Y, 0), Z) --> or (fcmp uno X, Y), Z
1596 Value *NewFCmp = Builder.CreateFCmp(Pred, X, Y);
1597 if (auto *NewFCmpInst = dyn_cast<FCmpInst>(NewFCmp)) {
1598 // Intersect FMF from the 2 source fcmps.
1599 NewFCmpInst->copyIRFlags(Op0);
1600 NewFCmpInst->andIRFlags(BO10);
1601 }
1602 return BinaryOperator::Create(Opcode, NewFCmp, BO11);
1603}
1604
1605/// Match variations of De Morgan's Laws:
1606/// (~A & ~B) == (~(A | B))
1607/// (~A | ~B) == (~(A & B))
1609 InstCombiner &IC) {
1610 const Instruction::BinaryOps Opcode = I.getOpcode();
1611 assert((Opcode == Instruction::And || Opcode == Instruction::Or) &&
1612 "Trying to match De Morgan's Laws with something other than and/or");
1613
1614 // Flip the logic operation.
1615 const Instruction::BinaryOps FlippedOpcode =
1616 (Opcode == Instruction::And) ? Instruction::Or : Instruction::And;
1617
1618 Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
1619 Value *A, *B;
1620 if (match(Op0, m_OneUse(m_Not(m_Value(A)))) &&
1621 match(Op1, m_OneUse(m_Not(m_Value(B)))) &&
1622 !IC.isFreeToInvert(A, A->hasOneUse()) &&
1623 !IC.isFreeToInvert(B, B->hasOneUse())) {
1624 Value *AndOr =
1625 IC.Builder.CreateBinOp(FlippedOpcode, A, B, I.getName() + ".demorgan");
1626 return BinaryOperator::CreateNot(AndOr);
1627 }
1628
1629 // The 'not' ops may require reassociation.
1630 // (A & ~B) & ~C --> A & ~(B | C)
1631 // (~B & A) & ~C --> A & ~(B | C)
1632 // (A | ~B) | ~C --> A | ~(B & C)
1633 // (~B | A) | ~C --> A | ~(B & C)
1634 Value *C;
1635 if (match(Op0, m_OneUse(m_c_BinOp(Opcode, m_Value(A), m_Not(m_Value(B))))) &&
1636 match(Op1, m_Not(m_Value(C)))) {
1637 Value *FlippedBO = IC.Builder.CreateBinOp(FlippedOpcode, B, C);
1638 return BinaryOperator::Create(Opcode, A, IC.Builder.CreateNot(FlippedBO));
1639 }
1640
1641 return nullptr;
1642}
1643
1644bool InstCombinerImpl::shouldOptimizeCast(CastInst *CI) {
1645 Value *CastSrc = CI->getOperand(0);
1646
1647 // Noop casts and casts of constants should be eliminated trivially.
1648 if (CI->getSrcTy() == CI->getDestTy() || isa<Constant>(CastSrc))
1649 return false;
1650
1651 // If this cast is paired with another cast that can be eliminated, we prefer
1652 // to have it eliminated.
1653 if (const auto *PrecedingCI = dyn_cast<CastInst>(CastSrc))
1654 if (isEliminableCastPair(PrecedingCI, CI))
1655 return false;
1656
1657 return true;
1658}
1659
1660/// Fold {and,or,xor} (cast X), C.
1662 InstCombinerImpl &IC) {
1663 Constant *C = dyn_cast<Constant>(Logic.getOperand(1));
1664 if (!C)
1665 return nullptr;
1666
1667 auto LogicOpc = Logic.getOpcode();
1668 Type *DestTy = Logic.getType();
1669 Type *SrcTy = Cast->getSrcTy();
1670
1671 // Move the logic operation ahead of a zext or sext if the constant is
1672 // unchanged in the smaller source type. Performing the logic in a smaller
1673 // type may provide more information to later folds, and the smaller logic
1674 // instruction may be cheaper (particularly in the case of vectors).
1675 Value *X;
1676 if (match(Cast, m_OneUse(m_ZExt(m_Value(X))))) {
1677 if (Constant *TruncC = IC.getLosslessUnsignedTrunc(C, SrcTy)) {
1678 // LogicOpc (zext X), C --> zext (LogicOpc X, C)
1679 Value *NewOp = IC.Builder.CreateBinOp(LogicOpc, X, TruncC);
1680 return new ZExtInst(NewOp, DestTy);
1681 }
1682 }
1683
1684 if (match(Cast, m_OneUse(m_SExtLike(m_Value(X))))) {
1685 if (Constant *TruncC = IC.getLosslessSignedTrunc(C, SrcTy)) {
1686 // LogicOpc (sext X), C --> sext (LogicOpc X, C)
1687 Value *NewOp = IC.Builder.CreateBinOp(LogicOpc, X, TruncC);
1688 return new SExtInst(NewOp, DestTy);
1689 }
1690 }
1691
1692 return nullptr;
1693}
1694
1695/// Fold {and,or,xor} (cast X), Y.
1696Instruction *InstCombinerImpl::foldCastedBitwiseLogic(BinaryOperator &I) {
1697 auto LogicOpc = I.getOpcode();
1698 assert(I.isBitwiseLogicOp() && "Unexpected opcode for bitwise logic folding");
1699
1700 Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
1701
1702 // fold bitwise(A >> BW - 1, zext(icmp)) (BW is the scalar bits of the
1703 // type of A)
1704 // -> bitwise(zext(A < 0), zext(icmp))
1705 // -> zext(bitwise(A < 0, icmp))
1706 auto FoldBitwiseICmpZeroWithICmp = [&](Value *Op0,
1707 Value *Op1) -> Instruction * {
1709 Value *A;
1710 bool IsMatched =
1711 match(Op0,
1713 m_Value(A),
1714 m_SpecificInt(Op0->getType()->getScalarSizeInBits() - 1)))) &&
1715 match(Op1, m_OneUse(m_ZExt(m_ICmp(Pred, m_Value(), m_Value()))));
1716
1717 if (!IsMatched)
1718 return nullptr;
1719
1720 auto *ICmpL =
1722 auto *ICmpR = cast<ZExtInst>(Op1)->getOperand(0);
1723 auto *BitwiseOp = Builder.CreateBinOp(LogicOpc, ICmpL, ICmpR);
1724
1725 return new ZExtInst(BitwiseOp, Op0->getType());
1726 };
1727
1728 if (auto *Ret = FoldBitwiseICmpZeroWithICmp(Op0, Op1))
1729 return Ret;
1730
1731 if (auto *Ret = FoldBitwiseICmpZeroWithICmp(Op1, Op0))
1732 return Ret;
1733
1734 CastInst *Cast0 = dyn_cast<CastInst>(Op0);
1735 if (!Cast0)
1736 return nullptr;
1737
1738 // This must be a cast from an integer or integer vector source type to allow
1739 // transformation of the logic operation to the source type.
1740 Type *DestTy = I.getType();
1741 Type *SrcTy = Cast0->getSrcTy();
1742 if (!SrcTy->isIntOrIntVectorTy())
1743 return nullptr;
1744
1745 if (Instruction *Ret = foldLogicCastConstant(I, Cast0, *this))
1746 return Ret;
1747
1748 CastInst *Cast1 = dyn_cast<CastInst>(Op1);
1749 if (!Cast1)
1750 return nullptr;
1751
1752 // Both operands of the logic operation are casts. The casts must be the
1753 // same kind for reduction.
1754 Instruction::CastOps CastOpcode = Cast0->getOpcode();
1755 if (CastOpcode != Cast1->getOpcode())
1756 return nullptr;
1757
1758 // If the source types do not match, but the casts are matching extends, we
1759 // can still narrow the logic op.
1760 if (SrcTy != Cast1->getSrcTy()) {
1761 Value *X, *Y;
1762 if (match(Cast0, m_OneUse(m_ZExtOrSExt(m_Value(X)))) &&
1763 match(Cast1, m_OneUse(m_ZExtOrSExt(m_Value(Y))))) {
1764 // Cast the narrower source to the wider source type.
1765 unsigned XNumBits = X->getType()->getScalarSizeInBits();
1766 unsigned YNumBits = Y->getType()->getScalarSizeInBits();
1767 if (XNumBits < YNumBits)
1768 X = Builder.CreateCast(CastOpcode, X, Y->getType());
1769 else
1770 Y = Builder.CreateCast(CastOpcode, Y, X->getType());
1771 // Do the logic op in the intermediate width, then widen more.
1772 Value *NarrowLogic = Builder.CreateBinOp(LogicOpc, X, Y);
1773 return CastInst::Create(CastOpcode, NarrowLogic, DestTy);
1774 }
1775
1776 // Give up for other cast opcodes.
1777 return nullptr;
1778 }
1779
1780 Value *Cast0Src = Cast0->getOperand(0);
1781 Value *Cast1Src = Cast1->getOperand(0);
1782
1783 // fold logic(cast(A), cast(B)) -> cast(logic(A, B))
1784 if ((Cast0->hasOneUse() || Cast1->hasOneUse()) &&
1785 shouldOptimizeCast(Cast0) && shouldOptimizeCast(Cast1)) {
1786 Value *NewOp = Builder.CreateBinOp(LogicOpc, Cast0Src, Cast1Src,
1787 I.getName());
1788 return CastInst::Create(CastOpcode, NewOp, DestTy);
1789 }
1790
1791 return nullptr;
1792}
1793
1795 InstCombiner::BuilderTy &Builder) {
1796 assert(I.getOpcode() == Instruction::And);
1797 Value *Op0 = I.getOperand(0);
1798 Value *Op1 = I.getOperand(1);
1799 Value *A, *B;
1800
1801 // Operand complexity canonicalization guarantees that the 'or' is Op0.
1802 // (A | B) & ~(A & B) --> A ^ B
1803 // (A | B) & ~(B & A) --> A ^ B
1804 if (match(&I, m_BinOp(m_Or(m_Value(A), m_Value(B)),
1806 return BinaryOperator::CreateXor(A, B);
1807
1808 // (A | ~B) & (~A | B) --> ~(A ^ B)
1809 // (A | ~B) & (B | ~A) --> ~(A ^ B)
1810 // (~B | A) & (~A | B) --> ~(A ^ B)
1811 // (~B | A) & (B | ~A) --> ~(A ^ B)
1812 if (Op0->hasOneUse() || Op1->hasOneUse())
1815 return BinaryOperator::CreateNot(Builder.CreateXor(A, B));
1816
1817 return nullptr;
1818}
1819
1821 InstCombiner::BuilderTy &Builder) {
1822 assert(I.getOpcode() == Instruction::Or);
1823 Value *Op0 = I.getOperand(0);
1824 Value *Op1 = I.getOperand(1);
1825 Value *A, *B;
1826
1827 // Operand complexity canonicalization guarantees that the 'and' is Op0.
1828 // (A & B) | ~(A | B) --> ~(A ^ B)
1829 // (A & B) | ~(B | A) --> ~(A ^ B)
1830 if (Op0->hasOneUse() || Op1->hasOneUse())
1831 if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
1833 return BinaryOperator::CreateNot(Builder.CreateXor(A, B));
1834
1835 // Operand complexity canonicalization guarantees that the 'xor' is Op0.
1836 // (A ^ B) | ~(A | B) --> ~(A & B)
1837 // (A ^ B) | ~(B | A) --> ~(A & B)
1838 if (Op0->hasOneUse() || Op1->hasOneUse())
1839 if (match(Op0, m_Xor(m_Value(A), m_Value(B))) &&
1841 return BinaryOperator::CreateNot(Builder.CreateAnd(A, B));
1842
1843 // (A & ~B) | (~A & B) --> A ^ B
1844 // (A & ~B) | (B & ~A) --> A ^ B
1845 // (~B & A) | (~A & B) --> A ^ B
1846 // (~B & A) | (B & ~A) --> A ^ B
1847 if (match(Op0, m_c_And(m_Value(A), m_Not(m_Value(B)))) &&
1849 return BinaryOperator::CreateXor(A, B);
1850
1851 return nullptr;
1852}
1853
1854/// Return true if a constant shift amount is always less than the specified
1855/// bit-width. If not, the shift could create poison in the narrower type.
1856static bool canNarrowShiftAmt(Constant *C, unsigned BitWidth) {
1857 APInt Threshold(C->getType()->getScalarSizeInBits(), BitWidth);
1858 return match(C, m_SpecificInt_ICMP(ICmpInst::ICMP_ULT, Threshold));
1859}
1860
1861/// Try to use narrower ops (sink zext ops) for an 'and' with binop operand and
1862/// a common zext operand: and (binop (zext X), C), (zext X).
1863Instruction *InstCombinerImpl::narrowMaskedBinOp(BinaryOperator &And) {
1864 // This transform could also apply to {or, and, xor}, but there are better
1865 // folds for those cases, so we don't expect those patterns here. AShr is not
1866 // handled because it should always be transformed to LShr in this sequence.
1867 // The subtract transform is different because it has a constant on the left.
1868 // Add/mul commute the constant to RHS; sub with constant RHS becomes add.
1869 Value *Op0 = And.getOperand(0), *Op1 = And.getOperand(1);
1870 Constant *C;
1871 if (!match(Op0, m_OneUse(m_Add(m_Specific(Op1), m_Constant(C)))) &&
1872 !match(Op0, m_OneUse(m_Mul(m_Specific(Op1), m_Constant(C)))) &&
1873 !match(Op0, m_OneUse(m_LShr(m_Specific(Op1), m_Constant(C)))) &&
1874 !match(Op0, m_OneUse(m_Shl(m_Specific(Op1), m_Constant(C)))) &&
1875 !match(Op0, m_OneUse(m_Sub(m_Constant(C), m_Specific(Op1)))))
1876 return nullptr;
1877
1878 Value *X;
1879 if (!match(Op1, m_ZExt(m_Value(X))) || Op1->hasNUsesOrMore(3))
1880 return nullptr;
1881
1882 Type *Ty = And.getType();
1883 if (!isa<VectorType>(Ty) && !shouldChangeType(Ty, X->getType()))
1884 return nullptr;
1885
1886 // If we're narrowing a shift, the shift amount must be safe (less than the
1887 // width) in the narrower type. If the shift amount is greater, instsimplify
1888 // usually handles that case, but we can't guarantee/assert it.
1889 Instruction::BinaryOps Opc = cast<BinaryOperator>(Op0)->getOpcode();
1890 if (Opc == Instruction::LShr || Opc == Instruction::Shl)
1891 if (!canNarrowShiftAmt(C, X->getType()->getScalarSizeInBits()))
1892 return nullptr;
1893
1894 // and (sub C, (zext X)), (zext X) --> zext (and (sub C', X), X)
1895 // and (binop (zext X), C), (zext X) --> zext (and (binop X, C'), X)
1896 Value *NewC = ConstantExpr::getTrunc(C, X->getType());
1897 Value *NewBO = Opc == Instruction::Sub ? Builder.CreateBinOp(Opc, NewC, X)
1898 : Builder.CreateBinOp(Opc, X, NewC);
1899 return new ZExtInst(Builder.CreateAnd(NewBO, X), Ty);
1900}
1901
1902/// Try folding relatively complex patterns for both And and Or operations
1903/// with all And and Or swapped.
1905 InstCombiner::BuilderTy &Builder) {
1906 const Instruction::BinaryOps Opcode = I.getOpcode();
1907 assert(Opcode == Instruction::And || Opcode == Instruction::Or);
1908
1909 // Flip the logic operation.
1910 const Instruction::BinaryOps FlippedOpcode =
1911 (Opcode == Instruction::And) ? Instruction::Or : Instruction::And;
1912
1913 Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
1914 Value *A, *B, *C, *X, *Y, *Dummy;
1915
1916 // Match following expressions:
1917 // (~(A | B) & C)
1918 // (~(A & B) | C)
1919 // Captures X = ~(A | B) or ~(A & B)
1920 const auto matchNotOrAnd =
1921 [Opcode, FlippedOpcode](Value *Op, auto m_A, auto m_B, auto m_C,
1922 Value *&X, bool CountUses = false) -> bool {
1923 if (CountUses && !Op->hasOneUse())
1924 return false;
1925
1926 if (match(Op, m_c_BinOp(FlippedOpcode,
1928 m_Not(m_c_BinOp(Opcode, m_A, m_B))),
1929 m_C)))
1930 return !CountUses || X->hasOneUse();
1931
1932 return false;
1933 };
1934
1935 // (~(A | B) & C) | ... --> ...
1936 // (~(A & B) | C) & ... --> ...
1937 // TODO: One use checks are conservative. We just need to check that a total
1938 // number of multiple used values does not exceed reduction
1939 // in operations.
1940 if (matchNotOrAnd(Op0, m_Value(A), m_Value(B), m_Value(C), X)) {
1941 // (~(A | B) & C) | (~(A | C) & B) --> (B ^ C) & ~A
1942 // (~(A & B) | C) & (~(A & C) | B) --> ~((B ^ C) & A)
1943 if (matchNotOrAnd(Op1, m_Specific(A), m_Specific(C), m_Specific(B), Dummy,
1944 true)) {
1945 Value *Xor = Builder.CreateXor(B, C);
1946 return (Opcode == Instruction::Or)
1947 ? BinaryOperator::CreateAnd(Xor, Builder.CreateNot(A))
1949 }
1950
1951 // (~(A | B) & C) | (~(B | C) & A) --> (A ^ C) & ~B
1952 // (~(A & B) | C) & (~(B & C) | A) --> ~((A ^ C) & B)
1953 if (matchNotOrAnd(Op1, m_Specific(B), m_Specific(C), m_Specific(A), Dummy,
1954 true)) {
1955 Value *Xor = Builder.CreateXor(A, C);
1956 return (Opcode == Instruction::Or)
1957 ? BinaryOperator::CreateAnd(Xor, Builder.CreateNot(B))
1959 }
1960
1961 // (~(A | B) & C) | ~(A | C) --> ~((B & C) | A)
1962 // (~(A & B) | C) & ~(A & C) --> ~((B | C) & A)
1963 if (match(Op1, m_OneUse(m_Not(m_OneUse(
1964 m_c_BinOp(Opcode, m_Specific(A), m_Specific(C)))))))
1966 Opcode, Builder.CreateBinOp(FlippedOpcode, B, C), A));
1967
1968 // (~(A | B) & C) | ~(B | C) --> ~((A & C) | B)
1969 // (~(A & B) | C) & ~(B & C) --> ~((A | C) & B)
1970 if (match(Op1, m_OneUse(m_Not(m_OneUse(
1971 m_c_BinOp(Opcode, m_Specific(B), m_Specific(C)))))))
1973 Opcode, Builder.CreateBinOp(FlippedOpcode, A, C), B));
1974
1975 // (~(A | B) & C) | ~(C | (A ^ B)) --> ~((A | B) & (C | (A ^ B)))
1976 // Note, the pattern with swapped and/or is not handled because the
1977 // result is more undefined than a source:
1978 // (~(A & B) | C) & ~(C & (A ^ B)) --> (A ^ B ^ C) | ~(A | C) is invalid.
1979 if (Opcode == Instruction::Or && Op0->hasOneUse() &&
1981 m_Value(Y),
1982 m_c_BinOp(Opcode, m_Specific(C),
1983 m_c_Xor(m_Specific(A), m_Specific(B)))))))) {
1984 // X = ~(A | B)
1985 // Y = (C | (A ^ B)
1986 Value *Or = cast<BinaryOperator>(X)->getOperand(0);
1987 return BinaryOperator::CreateNot(Builder.CreateAnd(Or, Y));
1988 }
1989 }
1990
1991 // (~A & B & C) | ... --> ...
1992 // (~A | B | C) | ... --> ...
1993 // TODO: One use checks are conservative. We just need to check that a total
1994 // number of multiple used values does not exceed reduction
1995 // in operations.
1996 if (match(Op0,
1997 m_OneUse(m_c_BinOp(FlippedOpcode,
1998 m_BinOp(FlippedOpcode, m_Value(B), m_Value(C)),
1999 m_CombineAnd(m_Value(X), m_Not(m_Value(A)))))) ||
2001 FlippedOpcode,
2002 m_c_BinOp(FlippedOpcode, m_Value(C),
2004 m_Value(B))))) {
2005 // X = ~A
2006 // (~A & B & C) | ~(A | B | C) --> ~(A | (B ^ C))
2007 // (~A | B | C) & ~(A & B & C) --> (~A | (B ^ C))
2008 if (match(Op1, m_OneUse(m_Not(m_c_BinOp(
2009 Opcode, m_c_BinOp(Opcode, m_Specific(A), m_Specific(B)),
2010 m_Specific(C))))) ||
2012 Opcode, m_c_BinOp(Opcode, m_Specific(B), m_Specific(C)),
2013 m_Specific(A))))) ||
2015 Opcode, m_c_BinOp(Opcode, m_Specific(A), m_Specific(C)),
2016 m_Specific(B)))))) {
2017 Value *Xor = Builder.CreateXor(B, C);
2018 return (Opcode == Instruction::Or)
2020 : BinaryOperator::CreateOr(Xor, X);
2021 }
2022
2023 // (~A & B & C) | ~(A | B) --> (C | ~B) & ~A
2024 // (~A | B | C) & ~(A & B) --> (C & ~B) | ~A
2025 if (match(Op1, m_OneUse(m_Not(m_OneUse(
2026 m_c_BinOp(Opcode, m_Specific(A), m_Specific(B)))))))
2028 FlippedOpcode, Builder.CreateBinOp(Opcode, C, Builder.CreateNot(B)),
2029 X);
2030
2031 // (~A & B & C) | ~(A | C) --> (B | ~C) & ~A
2032 // (~A | B | C) & ~(A & C) --> (B & ~C) | ~A
2033 if (match(Op1, m_OneUse(m_Not(m_OneUse(
2034 m_c_BinOp(Opcode, m_Specific(A), m_Specific(C)))))))
2036 FlippedOpcode, Builder.CreateBinOp(Opcode, B, Builder.CreateNot(C)),
2037 X);
2038 }
2039
2040 return nullptr;
2041}
2042
2043/// Try to reassociate a pair of binops so that values with one use only are
2044/// part of the same instruction. This may enable folds that are limited with
2045/// multi-use restrictions and makes it more likely to match other patterns that
2046/// are looking for a common operand.
2048 InstCombinerImpl::BuilderTy &Builder) {
2049 Instruction::BinaryOps Opcode = BO.getOpcode();
2050 Value *X, *Y, *Z;
2051 if (match(&BO,
2052 m_c_BinOp(Opcode, m_OneUse(m_BinOp(Opcode, m_Value(X), m_Value(Y))),
2053 m_OneUse(m_Value(Z))))) {
2054 if (!isa<Constant>(X) && !isa<Constant>(Y) && !isa<Constant>(Z)) {
2055 // (X op Y) op Z --> (Y op Z) op X
2056 if (!X->hasOneUse()) {
2057 Value *YZ = Builder.CreateBinOp(Opcode, Y, Z);
2058 return BinaryOperator::Create(Opcode, YZ, X);
2059 }
2060 // (X op Y) op Z --> (X op Z) op Y
2061 if (!Y->hasOneUse()) {
2062 Value *XZ = Builder.CreateBinOp(Opcode, X, Z);
2063 return BinaryOperator::Create(Opcode, XZ, Y);
2064 }
2065 }
2066 }
2067
2068 return nullptr;
2069}
2070
2071// Match
2072// (X + C2) | C
2073// (X + C2) ^ C
2074// (X + C2) & C
2075// and convert to do the bitwise logic first:
2076// (X | C) + C2
2077// (X ^ C) + C2
2078// (X & C) + C2
2079// iff bits affected by logic op are lower than last bit affected by math op
2081 InstCombiner::BuilderTy &Builder) {
2082 Type *Ty = I.getType();
2083 Instruction::BinaryOps OpC = I.getOpcode();
2084 Value *Op0 = I.getOperand(0);
2085 Value *Op1 = I.getOperand(1);
2086 Value *X;
2087 const APInt *C, *C2;
2088
2089 if (!(match(Op0, m_OneUse(m_Add(m_Value(X), m_APInt(C2)))) &&
2090 match(Op1, m_APInt(C))))
2091 return nullptr;
2092
2093 unsigned Width = Ty->getScalarSizeInBits();
2094 unsigned LastOneMath = Width - C2->countr_zero();
2095
2096 switch (OpC) {
2097 case Instruction::And:
2098 if (C->countl_one() < LastOneMath)
2099 return nullptr;
2100 break;
2101 case Instruction::Xor:
2102 case Instruction::Or:
2103 if (C->countl_zero() < LastOneMath)
2104 return nullptr;
2105 break;
2106 default:
2107 llvm_unreachable("Unexpected BinaryOp!");
2108 }
2109
2110 Value *NewBinOp = Builder.CreateBinOp(OpC, X, ConstantInt::get(Ty, *C));
2111 return BinaryOperator::CreateWithCopiedFlags(Instruction::Add, NewBinOp,
2112 ConstantInt::get(Ty, *C2), Op0);
2113}
2114
2115// binop(shift(ShiftedC1, ShAmt), shift(ShiftedC2, add(ShAmt, AddC))) ->
2116// shift(binop(ShiftedC1, shift(ShiftedC2, AddC)), ShAmt)
2117// where both shifts are the same and AddC is a valid shift amount.
2118Instruction *InstCombinerImpl::foldBinOpOfDisplacedShifts(BinaryOperator &I) {
2119 assert((I.isBitwiseLogicOp() || I.getOpcode() == Instruction::Add) &&
2120 "Unexpected opcode");
2121
2122 Value *ShAmt;
2123 Constant *ShiftedC1, *ShiftedC2, *AddC;
2124 Type *Ty = I.getType();
2125 unsigned BitWidth = Ty->getScalarSizeInBits();
2126 if (!match(&I, m_c_BinOp(m_Shift(m_ImmConstant(ShiftedC1), m_Value(ShAmt)),
2127 m_Shift(m_ImmConstant(ShiftedC2),
2128 m_AddLike(m_Deferred(ShAmt),
2129 m_ImmConstant(AddC))))))
2130 return nullptr;
2131
2132 // Make sure the add constant is a valid shift amount.
2133 if (!match(AddC,
2135 return nullptr;
2136
2137 // Avoid constant expressions.
2138 auto *Op0Inst = dyn_cast<Instruction>(I.getOperand(0));
2139 auto *Op1Inst = dyn_cast<Instruction>(I.getOperand(1));
2140 if (!Op0Inst || !Op1Inst)
2141 return nullptr;
2142
2143 // Both shifts must be the same.
2144 Instruction::BinaryOps ShiftOp =
2145 static_cast<Instruction::BinaryOps>(Op0Inst->getOpcode());
2146 if (ShiftOp != Op1Inst->getOpcode())
2147 return nullptr;
2148
2149 // For adds, only left shifts are supported.
2150 if (I.getOpcode() == Instruction::Add && ShiftOp != Instruction::Shl)
2151 return nullptr;
2152
2153 Value *NewC = Builder.CreateBinOp(
2154 I.getOpcode(), ShiftedC1, Builder.CreateBinOp(ShiftOp, ShiftedC2, AddC));
2155 return BinaryOperator::Create(ShiftOp, NewC, ShAmt);
2156}
2157
2158// Fold and/or/xor with two equal intrinsic IDs:
2159// bitwise(fshl (A, B, ShAmt), fshl(C, D, ShAmt))
2160// -> fshl(bitwise(A, C), bitwise(B, D), ShAmt)
2161// bitwise(fshr (A, B, ShAmt), fshr(C, D, ShAmt))
2162// -> fshr(bitwise(A, C), bitwise(B, D), ShAmt)
2163// bitwise(bswap(A), bswap(B)) -> bswap(bitwise(A, B))
2164// bitwise(bswap(A), C) -> bswap(bitwise(A, bswap(C)))
2165// bitwise(bitreverse(A), bitreverse(B)) -> bitreverse(bitwise(A, B))
2166// bitwise(bitreverse(A), C) -> bitreverse(bitwise(A, bitreverse(C)))
2167static Instruction *
2169 InstCombiner::BuilderTy &Builder) {
2170 assert(I.isBitwiseLogicOp() && "Should and/or/xor");
2171 if (!I.getOperand(0)->hasOneUse())
2172 return nullptr;
2173 IntrinsicInst *X = dyn_cast<IntrinsicInst>(I.getOperand(0));
2174 if (!X)
2175 return nullptr;
2176
2177 IntrinsicInst *Y = dyn_cast<IntrinsicInst>(I.getOperand(1));
2178 if (Y && (!Y->hasOneUse() || X->getIntrinsicID() != Y->getIntrinsicID()))
2179 return nullptr;
2180
2181 Intrinsic::ID IID = X->getIntrinsicID();
2182 const APInt *RHSC;
2183 // Try to match constant RHS.
2184 if (!Y && (!(IID == Intrinsic::bswap || IID == Intrinsic::bitreverse) ||
2185 !match(I.getOperand(1), m_APInt(RHSC))))
2186 return nullptr;
2187
2188 switch (IID) {
2189 case Intrinsic::fshl:
2190 case Intrinsic::fshr: {
2191 if (X->getOperand(2) != Y->getOperand(2))
2192 return nullptr;
2193 Value *NewOp0 =
2194 Builder.CreateBinOp(I.getOpcode(), X->getOperand(0), Y->getOperand(0));
2195 Value *NewOp1 =
2196 Builder.CreateBinOp(I.getOpcode(), X->getOperand(1), Y->getOperand(1));
2197 Function *F = Intrinsic::getDeclaration(I.getModule(), IID, I.getType());
2198 return CallInst::Create(F, {NewOp0, NewOp1, X->getOperand(2)});
2199 }
2200 case Intrinsic::bswap:
2201 case Intrinsic::bitreverse: {
2202 Value *NewOp0 = Builder.CreateBinOp(
2203 I.getOpcode(), X->getOperand(0),
2204 Y ? Y->getOperand(0)
2205 : ConstantInt::get(I.getType(), IID == Intrinsic::bswap
2206 ? RHSC->byteSwap()
2207 : RHSC->reverseBits()));
2208 Function *F = Intrinsic::getDeclaration(I.getModule(), IID, I.getType());
2209 return CallInst::Create(F, {NewOp0});
2210 }
2211 default:
2212 return nullptr;
2213 }
2214}
2215
2216// Try to simplify V by replacing occurrences of Op with RepOp, but only look
2217// through bitwise operations. In particular, for X | Y we try to replace Y with
2218// 0 inside X and for X & Y we try to replace Y with -1 inside X.
2219// Return the simplified result of X if successful, and nullptr otherwise.
2220// If SimplifyOnly is true, no new instructions will be created.
2222 bool SimplifyOnly,
2223 InstCombinerImpl &IC,
2224 unsigned Depth = 0) {
2225 if (Op == RepOp)
2226 return nullptr;
2227
2228 if (V == Op)
2229 return RepOp;
2230
2231 auto *I = dyn_cast<BinaryOperator>(V);
2232 if (!I || !I->isBitwiseLogicOp() || Depth >= 3)
2233 return nullptr;
2234
2235 if (!I->hasOneUse())
2236 SimplifyOnly = true;
2237
2238 Value *NewOp0 = simplifyAndOrWithOpReplaced(I->getOperand(0), Op, RepOp,
2239 SimplifyOnly, IC, Depth + 1);
2240 Value *NewOp1 = simplifyAndOrWithOpReplaced(I->getOperand(1), Op, RepOp,
2241 SimplifyOnly, IC, Depth + 1);
2242 if (!NewOp0 && !NewOp1)
2243 return nullptr;
2244
2245 if (!NewOp0)
2246 NewOp0 = I->getOperand(0);
2247 if (!NewOp1)
2248 NewOp1 = I->getOperand(1);
2249
2250 if (Value *Res = simplifyBinOp(I->getOpcode(), NewOp0, NewOp1,
2252 return Res;
2253
2254 if (SimplifyOnly)
2255 return nullptr;
2256 return IC.Builder.CreateBinOp(I->getOpcode(), NewOp0, NewOp1);
2257}
2258
2259// FIXME: We use commutative matchers (m_c_*) for some, but not all, matches
2260// here. We should standardize that construct where it is needed or choose some
2261// other way to ensure that commutated variants of patterns are not missed.
2263 Type *Ty = I.getType();
2264
2265 if (Value *V = simplifyAndInst(I.getOperand(0), I.getOperand(1),
2267 return replaceInstUsesWith(I, V);
2268
2270 return &I;
2271
2273 return X;
2274
2276 return Phi;
2277
2278 // See if we can simplify any instructions used by the instruction whose sole
2279 // purpose is to compute bits we don't care about.
2281 return &I;
2282
2283 // Do this before using distributive laws to catch simple and/or/not patterns.
2285 return Xor;
2286
2288 return X;
2289
2290 // (A|B)&(A|C) -> A|(B&C) etc
2292 return replaceInstUsesWith(I, V);
2293
2295 return R;
2296
2297 Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
2298
2299 Value *X, *Y;
2300 const APInt *C;
2301 if ((match(Op0, m_OneUse(m_LogicalShift(m_One(), m_Value(X)))) ||
2302 (match(Op0, m_OneUse(m_Shl(m_APInt(C), m_Value(X)))) && (*C)[0])) &&
2303 match(Op1, m_One())) {
2304 // (1 >> X) & 1 --> zext(X == 0)
2305 // (C << X) & 1 --> zext(X == 0), when C is odd
2306 Value *IsZero = Builder.CreateICmpEQ(X, ConstantInt::get(Ty, 0));
2307 return new ZExtInst(IsZero, Ty);
2308 }
2309
2310 // (-(X & 1)) & Y --> (X & 1) == 0 ? 0 : Y
2311 Value *Neg;
2312 if (match(&I,
2314 m_OneUse(m_Neg(m_And(m_Value(), m_One())))),
2315 m_Value(Y)))) {
2316 Value *Cmp = Builder.CreateIsNull(Neg);
2318 }
2319
2320 // Canonicalize:
2321 // (X +/- Y) & Y --> ~X & Y when Y is a power of 2.
2324 m_Sub(m_Value(X), m_Deferred(Y)))))) &&
2325 isKnownToBeAPowerOfTwo(Y, /*OrZero*/ true, /*Depth*/ 0, &I))
2326 return BinaryOperator::CreateAnd(Builder.CreateNot(X), Y);
2327
2328 if (match(Op1, m_APInt(C))) {
2329 const APInt *XorC;
2330 if (match(Op0, m_OneUse(m_Xor(m_Value(X), m_APInt(XorC))))) {
2331 // (X ^ C1) & C2 --> (X & C2) ^ (C1&C2)
2332 Constant *NewC = ConstantInt::get(Ty, *C & *XorC);
2333 Value *And = Builder.CreateAnd(X, Op1);
2334 And->takeName(Op0);
2335 return BinaryOperator::CreateXor(And, NewC);
2336 }
2337
2338 const APInt *OrC;
2339 if (match(Op0, m_OneUse(m_Or(m_Value(X), m_APInt(OrC))))) {
2340 // (X | C1) & C2 --> (X & C2^(C1&C2)) | (C1&C2)
2341 // NOTE: This reduces the number of bits set in the & mask, which
2342 // can expose opportunities for store narrowing for scalars.
2343 // NOTE: SimplifyDemandedBits should have already removed bits from C1
2344 // that aren't set in C2. Meaning we can replace (C1&C2) with C1 in
2345 // above, but this feels safer.
2346 APInt Together = *C & *OrC;
2347 Value *And = Builder.CreateAnd(X, ConstantInt::get(Ty, Together ^ *C));
2348 And->takeName(Op0);
2349 return BinaryOperator::CreateOr(And, ConstantInt::get(Ty, Together));
2350 }
2351
2352 unsigned Width = Ty->getScalarSizeInBits();
2353 const APInt *ShiftC;
2354 if (match(Op0, m_OneUse(m_SExt(m_AShr(m_Value(X), m_APInt(ShiftC))))) &&
2355 ShiftC->ult(Width)) {
2356 if (*C == APInt::getLowBitsSet(Width, Width - ShiftC->getZExtValue())) {
2357 // We are clearing high bits that were potentially set by sext+ashr:
2358 // and (sext (ashr X, ShiftC)), C --> lshr (sext X), ShiftC
2359 Value *Sext = Builder.CreateSExt(X, Ty);
2360 Constant *ShAmtC = ConstantInt::get(Ty, ShiftC->zext(Width));
2361 return BinaryOperator::CreateLShr(Sext, ShAmtC);
2362 }
2363 }
2364
2365 // If this 'and' clears the sign-bits added by ashr, replace with lshr:
2366 // and (ashr X, ShiftC), C --> lshr X, ShiftC
2367 if (match(Op0, m_AShr(m_Value(X), m_APInt(ShiftC))) && ShiftC->ult(Width) &&
2368 C->isMask(Width - ShiftC->getZExtValue()))
2369 return BinaryOperator::CreateLShr(X, ConstantInt::get(Ty, *ShiftC));
2370
2371 const APInt *AddC;
2372 if (match(Op0, m_Add(m_Value(X), m_APInt(AddC)))) {
2373 // If we are masking the result of the add down to exactly one bit and
2374 // the constant we are adding has no bits set below that bit, then the
2375 // add is flipping a single bit. Example:
2376 // (X + 4) & 4 --> (X & 4) ^ 4
2377 if (Op0->hasOneUse() && C->isPowerOf2() && (*AddC & (*C - 1)) == 0) {
2378 assert((*C & *AddC) != 0 && "Expected common bit");
2379 Value *NewAnd = Builder.CreateAnd(X, Op1);
2380 return BinaryOperator::CreateXor(NewAnd, Op1);
2381 }
2382 }
2383
2384 // ((C1 OP zext(X)) & C2) -> zext((C1 OP X) & C2) if C2 fits in the
2385 // bitwidth of X and OP behaves well when given trunc(C1) and X.
2386 auto isNarrowableBinOpcode = [](BinaryOperator *B) {
2387 switch (B->getOpcode()) {
2388 case Instruction::Xor:
2389 case Instruction::Or:
2390 case Instruction::Mul:
2391 case Instruction::Add:
2392 case Instruction::Sub:
2393 return true;
2394 default:
2395 return false;
2396 }
2397 };
2398 BinaryOperator *BO;
2399 if (match(Op0, m_OneUse(m_BinOp(BO))) && isNarrowableBinOpcode(BO)) {
2400 Instruction::BinaryOps BOpcode = BO->getOpcode();
2401 Value *X;
2402 const APInt *C1;
2403 // TODO: The one-use restrictions could be relaxed a little if the AND
2404 // is going to be removed.
2405 // Try to narrow the 'and' and a binop with constant operand:
2406 // and (bo (zext X), C1), C --> zext (and (bo X, TruncC1), TruncC)
2407 if (match(BO, m_c_BinOp(m_OneUse(m_ZExt(m_Value(X))), m_APInt(C1))) &&
2408 C->isIntN(X->getType()->getScalarSizeInBits())) {
2409 unsigned XWidth = X->getType()->getScalarSizeInBits();
2410 Constant *TruncC1 = ConstantInt::get(X->getType(), C1->trunc(XWidth));
2411 Value *BinOp = isa<ZExtInst>(BO->getOperand(0))
2412 ? Builder.CreateBinOp(BOpcode, X, TruncC1)
2413 : Builder.CreateBinOp(BOpcode, TruncC1, X);
2414 Constant *TruncC = ConstantInt::get(X->getType(), C->trunc(XWidth));
2415 Value *And = Builder.CreateAnd(BinOp, TruncC);
2416 return new ZExtInst(And, Ty);
2417 }
2418
2419 // Similar to above: if the mask matches the zext input width, then the
2420 // 'and' can be eliminated, so we can truncate the other variable op:
2421 // and (bo (zext X), Y), C --> zext (bo X, (trunc Y))
2422 if (isa<Instruction>(BO->getOperand(0)) &&
2423 match(BO->getOperand(0), m_OneUse(m_ZExt(m_Value(X)))) &&
2424 C->isMask(X->getType()->getScalarSizeInBits())) {
2425 Y = BO->getOperand(1);
2426 Value *TrY = Builder.CreateTrunc(Y, X->getType(), Y->getName() + ".tr");
2427 Value *NewBO =
2428 Builder.CreateBinOp(BOpcode, X, TrY, BO->getName() + ".narrow");
2429 return new ZExtInst(NewBO, Ty);
2430 }
2431 // and (bo Y, (zext X)), C --> zext (bo (trunc Y), X)
2432 if (isa<Instruction>(BO->getOperand(1)) &&
2433 match(BO->getOperand(1), m_OneUse(m_ZExt(m_Value(X)))) &&
2434 C->isMask(X->getType()->getScalarSizeInBits())) {
2435 Y = BO->getOperand(0);
2436 Value *TrY = Builder.CreateTrunc(Y, X->getType(), Y->getName() + ".tr");
2437 Value *NewBO =
2438 Builder.CreateBinOp(BOpcode, TrY, X, BO->getName() + ".narrow");
2439 return new ZExtInst(NewBO, Ty);
2440 }
2441 }
2442
2443 // This is intentionally placed after the narrowing transforms for
2444 // efficiency (transform directly to the narrow logic op if possible).
2445 // If the mask is only needed on one incoming arm, push the 'and' op up.
2446 if (match(Op0, m_OneUse(m_Xor(m_Value(X), m_Value(Y)))) ||
2447 match(Op0, m_OneUse(m_Or(m_Value(X), m_Value(Y))))) {
2448 APInt NotAndMask(~(*C));
2449 BinaryOperator::BinaryOps BinOp = cast<BinaryOperator>(Op0)->getOpcode();
2450 if (MaskedValueIsZero(X, NotAndMask, 0, &I)) {
2451 // Not masking anything out for the LHS, move mask to RHS.
2452 // and ({x}or X, Y), C --> {x}or X, (and Y, C)
2453 Value *NewRHS = Builder.CreateAnd(Y, Op1, Y->getName() + ".masked");
2454 return BinaryOperator::Create(BinOp, X, NewRHS);
2455 }
2456 if (!isa<Constant>(Y) && MaskedValueIsZero(Y, NotAndMask, 0, &I)) {
2457 // Not masking anything out for the RHS, move mask to LHS.
2458 // and ({x}or X, Y), C --> {x}or (and X, C), Y
2459 Value *NewLHS = Builder.CreateAnd(X, Op1, X->getName() + ".masked");
2460 return BinaryOperator::Create(BinOp, NewLHS, Y);
2461 }
2462 }
2463
2464 // When the mask is a power-of-2 constant and op0 is a shifted-power-of-2
2465 // constant, test if the shift amount equals the offset bit index:
2466 // (ShiftC << X) & C --> X == (log2(C) - log2(ShiftC)) ? C : 0
2467 // (ShiftC >> X) & C --> X == (log2(ShiftC) - log2(C)) ? C : 0
2468 if (C->isPowerOf2() &&
2469 match(Op0, m_OneUse(m_LogicalShift(m_Power2(ShiftC), m_Value(X))))) {
2470 int Log2ShiftC = ShiftC->exactLogBase2();
2471 int Log2C = C->exactLogBase2();
2472 bool IsShiftLeft =
2473 cast<BinaryOperator>(Op0)->getOpcode() == Instruction::Shl;
2474 int BitNum = IsShiftLeft ? Log2C - Log2ShiftC : Log2ShiftC - Log2C;
2475 assert(BitNum >= 0 && "Expected demanded bits to handle impossible mask");
2476 Value *Cmp = Builder.CreateICmpEQ(X, ConstantInt::get(Ty, BitNum));
2477 return SelectInst::Create(Cmp, ConstantInt::get(Ty, *C),
2479 }
2480
2481 Constant *C1, *C2;
2482 const APInt *C3 = C;
2483 Value *X;
2484 if (C3->isPowerOf2()) {
2485 Constant *Log2C3 = ConstantInt::get(Ty, C3->countr_zero());
2487 m_ImmConstant(C2)))) &&
2488 match(C1, m_Power2())) {
2490 Constant *LshrC = ConstantExpr::getAdd(C2, Log2C3);
2491 KnownBits KnownLShrc = computeKnownBits(LshrC, 0, nullptr);
2492 if (KnownLShrc.getMaxValue().ult(Width)) {
2493 // iff C1,C3 is pow2 and C2 + cttz(C3) < BitWidth:
2494 // ((C1 << X) >> C2) & C3 -> X == (cttz(C3)+C2-cttz(C1)) ? C3 : 0
2495 Constant *CmpC = ConstantExpr::getSub(LshrC, Log2C1);
2496 Value *Cmp = Builder.CreateICmpEQ(X, CmpC);
2497 return SelectInst::Create(Cmp, ConstantInt::get(Ty, *C3),
2499 }
2500 }
2501
2503 m_ImmConstant(C2)))) &&
2504 match(C1, m_Power2())) {
2506 Constant *Cmp =
2508 if (Cmp && Cmp->isZeroValue()) {
2509 // iff C1,C3 is pow2 and Log2(C3) >= C2:
2510 // ((C1 >> X) << C2) & C3 -> X == (cttz(C1)+C2-cttz(C3)) ? C3 : 0
2511 Constant *ShlC = ConstantExpr::getAdd(C2, Log2C1);
2512 Constant *CmpC = ConstantExpr::getSub(ShlC, Log2C3);
2513 Value *Cmp = Builder.CreateICmpEQ(X, CmpC);
2514 return SelectInst::Create(Cmp, ConstantInt::get(Ty, *C3),
2516 }
2517 }
2518 }
2519 }
2520
2521 // If we are clearing the sign bit of a floating-point value, convert this to
2522 // fabs, then cast back to integer.
2523 //
2524 // This is a generous interpretation for noimplicitfloat, this is not a true
2525 // floating-point operation.
2526 //
2527 // Assumes any IEEE-represented type has the sign bit in the high bit.
2528 // TODO: Unify with APInt matcher. This version allows undef unlike m_APInt
2529 Value *CastOp;
2530 if (match(Op0, m_ElementWiseBitCast(m_Value(CastOp))) &&
2531 match(Op1, m_MaxSignedValue()) &&
2533 Attribute::NoImplicitFloat)) {
2534 Type *EltTy = CastOp->getType()->getScalarType();
2535 if (EltTy->isFloatingPointTy() && EltTy->isIEEE()) {
2536 Value *FAbs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, CastOp);
2537 return new BitCastInst(FAbs, I.getType());
2538 }
2539 }
2540
2541 // and(shl(zext(X), Y), SignMask) -> and(sext(X), SignMask)
2542 // where Y is a valid shift amount.
2544 m_SignMask())) &&
2548 Ty->getScalarSizeInBits() -
2549 X->getType()->getScalarSizeInBits())))) {
2550 auto *SExt = Builder.CreateSExt(X, Ty, X->getName() + ".signext");
2551 return BinaryOperator::CreateAnd(SExt, Op1);
2552 }
2553
2554 if (Instruction *Z = narrowMaskedBinOp(I))
2555 return Z;
2556
2557 if (I.getType()->isIntOrIntVectorTy(1)) {
2558 if (auto *SI0 = dyn_cast<SelectInst>(Op0)) {
2559 if (auto *R =
2560 foldAndOrOfSelectUsingImpliedCond(Op1, *SI0, /* IsAnd */ true))
2561 return R;
2562 }
2563 if (auto *SI1 = dyn_cast<SelectInst>(Op1)) {
2564 if (auto *R =
2565 foldAndOrOfSelectUsingImpliedCond(Op0, *SI1, /* IsAnd */ true))
2566 return R;
2567 }
2568 }
2569
2570 if (Instruction *FoldedLogic = foldBinOpIntoSelectOrPhi(I))
2571 return FoldedLogic;
2572
2573 if (Instruction *DeMorgan = matchDeMorgansLaws(I, *this))
2574 return DeMorgan;
2575
2576 {
2577 Value *A, *B, *C;
2578 // A & ~(A ^ B) --> A & B
2579 if (match(Op1, m_Not(m_c_Xor(m_Specific(Op0), m_Value(B)))))
2580 return BinaryOperator::CreateAnd(Op0, B);
2581 // ~(A ^ B) & A --> A & B
2582 if (match(Op0, m_Not(m_c_Xor(m_Specific(Op1), m_Value(B)))))
2583 return BinaryOperator::CreateAnd(Op1, B);
2584
2585 // (A ^ B) & ((B ^ C) ^ A) -> (A ^ B) & ~C
2586 if (match(Op0, m_Xor(m_Value(A), m_Value(B))) &&
2587 match(Op1, m_Xor(m_Xor(m_Specific(B), m_Value(C)), m_Specific(A)))) {
2588 Value *NotC = Op1->hasOneUse()
2590 : getFreelyInverted(C, C->hasOneUse(), &Builder);
2591 if (NotC != nullptr)
2592 return BinaryOperator::CreateAnd(Op0, NotC);
2593 }
2594
2595 // ((A ^ C) ^ B) & (B ^ A) -> (B ^ A) & ~C
2596 if (match(Op0, m_Xor(m_Xor(m_Value(A), m_Value(C)), m_Value(B))) &&
2597 match(Op1, m_Xor(m_Specific(B), m_Specific(A)))) {
2598 Value *NotC = Op0->hasOneUse()
2600 : getFreelyInverted(C, C->hasOneUse(), &Builder);
2601 if (NotC != nullptr)
2602 return BinaryOperator::CreateAnd(Op1, Builder.CreateNot(C));
2603 }
2604
2605 // (A | B) & (~A ^ B) -> A & B
2606 // (A | B) & (B ^ ~A) -> A & B
2607 // (B | A) & (~A ^ B) -> A & B
2608 // (B | A) & (B ^ ~A) -> A & B
2609 if (match(Op1, m_c_Xor(m_Not(m_Value(A)), m_Value(B))) &&
2610 match(Op0, m_c_Or(m_Specific(A), m_Specific(B))))
2611 return BinaryOperator::CreateAnd(A, B);
2612
2613 // (~A ^ B) & (A | B) -> A & B
2614 // (~A ^ B) & (B | A) -> A & B
2615 // (B ^ ~A) & (A | B) -> A & B
2616 // (B ^ ~A) & (B | A) -> A & B
2617 if (match(Op0, m_c_Xor(m_Not(m_Value(A)), m_Value(B))) &&
2618 match(Op1, m_c_Or(m_Specific(A), m_Specific(B))))
2619 return BinaryOperator::CreateAnd(A, B);
2620
2621 // (~A | B) & (A ^ B) -> ~A & B
2622 // (~A | B) & (B ^ A) -> ~A & B
2623 // (B | ~A) & (A ^ B) -> ~A & B
2624 // (B | ~A) & (B ^ A) -> ~A & B
2625 if (match(Op0, m_c_Or(m_Not(m_Value(A)), m_Value(B))) &&
2627 return BinaryOperator::CreateAnd(Builder.CreateNot(A), B);
2628
2629 // (A ^ B) & (~A | B) -> ~A & B
2630 // (B ^ A) & (~A | B) -> ~A & B
2631 // (A ^ B) & (B | ~A) -> ~A & B
2632 // (B ^ A) & (B | ~A) -> ~A & B
2633 if (match(Op1, m_c_Or(m_Not(m_Value(A)), m_Value(B))) &&
2635 return BinaryOperator::CreateAnd(Builder.CreateNot(A), B);
2636 }
2637
2638 {
2639 ICmpInst *LHS = dyn_cast<ICmpInst>(Op0);
2640 ICmpInst *RHS = dyn_cast<ICmpInst>(Op1);
2641 if (LHS && RHS)
2642 if (Value *Res = foldAndOrOfICmps(LHS, RHS, I, /* IsAnd */ true))
2643 return replaceInstUsesWith(I, Res);
2644
2645 // TODO: Make this recursive; it's a little tricky because an arbitrary
2646 // number of 'and' instructions might have to be created.
2647 if (LHS && match(Op1, m_OneUse(m_LogicalAnd(m_Value(X), m_Value(Y))))) {
2648 bool IsLogical = isa<SelectInst>(Op1);
2649 // LHS & (X && Y) --> (LHS && X) && Y
2650 if (auto *Cmp = dyn_cast<ICmpInst>(X))
2651 if (Value *Res =
2652 foldAndOrOfICmps(LHS, Cmp, I, /* IsAnd */ true, IsLogical))
2653 return replaceInstUsesWith(I, IsLogical
2654 ? Builder.CreateLogicalAnd(Res, Y)
2655 : Builder.CreateAnd(Res, Y));
2656 // LHS & (X && Y) --> X && (LHS & Y)
2657 if (auto *Cmp = dyn_cast<ICmpInst>(Y))
2658 if (Value *Res = foldAndOrOfICmps(LHS, Cmp, I, /* IsAnd */ true,
2659 /* IsLogical */ false))
2660 return replaceInstUsesWith(I, IsLogical
2661 ? Builder.CreateLogicalAnd(X, Res)
2662 : Builder.CreateAnd(X, Res));
2663 }
2664 if (RHS && match(Op0, m_OneUse(m_LogicalAnd(m_Value(X), m_Value(Y))))) {
2665 bool IsLogical = isa<SelectInst>(Op0);
2666 // (X && Y) & RHS --> (X && RHS) && Y
2667 if (auto *Cmp = dyn_cast<ICmpInst>(X))
2668 if (Value *Res =
2669 foldAndOrOfICmps(Cmp, RHS, I, /* IsAnd */ true, IsLogical))
2670 return replaceInstUsesWith(I, IsLogical
2671 ? Builder.CreateLogicalAnd(Res, Y)
2672 : Builder.CreateAnd(Res, Y));
2673 // (X && Y) & RHS --> X && (Y & RHS)
2674 if (auto *Cmp = dyn_cast<ICmpInst>(Y))
2675 if (Value *Res = foldAndOrOfICmps(Cmp, RHS, I, /* IsAnd */ true,
2676 /* IsLogical */ false))
2677 return replaceInstUsesWith(I, IsLogical
2678 ? Builder.CreateLogicalAnd(X, Res)
2679 : Builder.CreateAnd(X, Res));
2680 }
2681 }
2682
2683 if (FCmpInst *LHS = dyn_cast<FCmpInst>(I.getOperand(0)))
2684 if (FCmpInst *RHS = dyn_cast<FCmpInst>(I.getOperand(1)))
2685 if (Value *Res = foldLogicOfFCmps(LHS, RHS, /*IsAnd*/ true))
2686 return replaceInstUsesWith(I, Res);
2687
2688 if (Instruction *FoldedFCmps = reassociateFCmps(I, Builder))
2689 return FoldedFCmps;
2690
2691 if (Instruction *CastedAnd = foldCastedBitwiseLogic(I))
2692 return CastedAnd;
2693
2694 if (Instruction *Sel = foldBinopOfSextBoolToSelect(I))
2695 return Sel;
2696
2697 // and(sext(A), B) / and(B, sext(A)) --> A ? B : 0, where A is i1 or <N x i1>.
2698 // TODO: Move this into foldBinopOfSextBoolToSelect as a more generalized fold
2699 // with binop identity constant. But creating a select with non-constant
2700 // arm may not be reversible due to poison semantics. Is that a good
2701 // canonicalization?
2702 Value *A, *B;
2703 if (match(&I, m_c_And(m_SExt(m_Value(A)), m_Value(B))) &&
2704 A->getType()->isIntOrIntVectorTy(1))
2706
2707 // Similarly, a 'not' of the bool translates to a swap of the select arms:
2708 // ~sext(A) & B / B & ~sext(A) --> A ? 0 : B
2709 if (match(&I, m_c_And(m_Not(m_SExt(m_Value(A))), m_Value(B))) &&
2710 A->getType()->isIntOrIntVectorTy(1))
2712
2713 // and(zext(A), B) -> A ? (B & 1) : 0
2714 if (match(&I, m_c_And(m_OneUse(m_ZExt(m_Value(A))), m_Value(B))) &&
2715 A->getType()->isIntOrIntVectorTy(1))
2716 return SelectInst::Create(A, Builder.CreateAnd(B, ConstantInt::get(Ty, 1)),
2718
2719 // (-1 + A) & B --> A ? 0 : B where A is 0/1.
2721 m_Value(B)))) {
2722 if (A->getType()->isIntOrIntVectorTy(1))
2724 if (computeKnownBits(A, /* Depth */ 0, &I).countMaxActiveBits() <= 1) {
2725 return SelectInst::Create(
2728 }
2729 }
2730
2731 // (iN X s>> (N-1)) & Y --> (X s< 0) ? Y : 0 -- with optional sext
2734 m_Value(Y))) &&
2735 *C == X->getType()->getScalarSizeInBits() - 1) {
2736 Value *IsNeg = Builder.CreateIsNeg(X, "isneg");
2738 }
2739 // If there's a 'not' of the shifted value, swap the select operands:
2740 // ~(iN X s>> (N-1)) & Y --> (X s< 0) ? 0 : Y -- with optional sext
2743 m_Value(Y))) &&
2744 *C == X->getType()->getScalarSizeInBits() - 1) {
2745 Value *IsNeg = Builder.CreateIsNeg(X, "isneg");
2747 }
2748
2749 // (~x) & y --> ~(x | (~y)) iff that gets rid of inversions
2751 return &I;
2752
2753 // An and recurrence w/loop invariant step is equivelent to (and start, step)
2754 PHINode *PN = nullptr;
2755 Value *Start = nullptr, *Step = nullptr;
2756 if (matchSimpleRecurrence(&I, PN, Start, Step) && DT.dominates(Step, PN))
2757 return replaceInstUsesWith(I, Builder.CreateAnd(Start, Step));
2758
2760 return R;
2761
2762 if (Instruction *Canonicalized = canonicalizeLogicFirst(I, Builder))
2763 return Canonicalized;
2764
2765 if (Instruction *Folded = foldLogicOfIsFPClass(I, Op0, Op1))
2766 return Folded;
2767
2768 if (Instruction *Res = foldBinOpOfDisplacedShifts(I))
2769 return Res;
2770
2772 return Res;
2773
2774 if (Value *V =
2776 /*SimplifyOnly*/ false, *this))
2777 return BinaryOperator::CreateAnd(V, Op1);
2778 if (Value *V =
2780 /*SimplifyOnly*/ false, *this))
2781 return BinaryOperator::CreateAnd(Op0, V);
2782
2783 return nullptr;
2784}
2785
2787 bool MatchBSwaps,
2788 bool MatchBitReversals) {
2790 if (!recognizeBSwapOrBitReverseIdiom(&I, MatchBSwaps, MatchBitReversals,
2791 Insts))
2792 return nullptr;
2793 Instruction *LastInst = Insts.pop_back_val();
2794 LastInst->removeFromParent();
2795
2796 for (auto *Inst : Insts)
2797 Worklist.push(Inst);
2798 return LastInst;
2799}
2800
2801std::optional<std::pair<Intrinsic::ID, SmallVector<Value *, 3>>>
2803 // TODO: Can we reduce the code duplication between this and the related
2804 // rotate matching code under visitSelect and visitTrunc?
2805 assert(Or.getOpcode() == BinaryOperator::Or && "Expecting or instruction");
2806
2807 unsigned Width = Or.getType()->getScalarSizeInBits();
2808
2809 Instruction *Or0, *Or1;
2810 if (!match(Or.getOperand(0), m_Instruction(Or0)) ||
2811 !match(Or.getOperand(1), m_Instruction(Or1)))
2812 return std::nullopt;
2813
2814 bool IsFshl = true; // Sub on LSHR.
2815 SmallVector<Value *, 3> FShiftArgs;
2816
2817 // First, find an or'd pair of opposite shifts:
2818 // or (lshr ShVal0, ShAmt0), (shl ShVal1, ShAmt1)
2819 if (isa<BinaryOperator>(Or0) && isa<BinaryOperator>(Or1)) {
2820 Value *ShVal0, *ShVal1, *ShAmt0, *ShAmt1;
2821 if (!match(Or0,
2822 m_OneUse(m_LogicalShift(m_Value(ShVal0), m_Value(ShAmt0)))) ||
2823 !match(Or1,
2824 m_OneUse(m_LogicalShift(m_Value(ShVal1), m_Value(ShAmt1)))) ||
2825 Or0->getOpcode() == Or1->getOpcode())
2826 return std::nullopt;
2827
2828 // Canonicalize to or(shl(ShVal0, ShAmt0), lshr(ShVal1, ShAmt1)).
2829 if (Or0->getOpcode() == BinaryOperator::LShr) {
2830 std::swap(Or0, Or1);
2831 std::swap(ShVal0, ShVal1);
2832 std::swap(ShAmt0, ShAmt1);
2833 }
2834 assert(Or0->getOpcode() == BinaryOperator::Shl &&
2835 Or1->getOpcode() == BinaryOperator::LShr &&
2836 "Illegal or(shift,shift) pair");
2837
2838 // Match the shift amount operands for a funnel shift pattern. This always
2839 // matches a subtraction on the R operand.
2840 auto matchShiftAmount = [&](Value *L, Value *R, unsigned Width) -> Value * {
2841 // Check for constant shift amounts that sum to the bitwidth.
2842 const APInt *LI, *RI;
2844 if (LI->ult(Width) && RI->ult(Width) && (*LI + *RI) == Width)
2845 return ConstantInt::get(L->getType(), *LI);
2846
2847 Constant *LC, *RC;
2848 if (match(L, m_Constant(LC)) && match(R, m_Constant(RC)) &&
2849 match(L,
2850 m_SpecificInt_ICMP(ICmpInst::ICMP_ULT, APInt(Width, Width))) &&
2851 match(R,
2852 m_SpecificInt_ICMP(ICmpInst::ICMP_ULT, APInt(Width, Width))) &&
2854 return ConstantExpr::mergeUndefsWith(LC, RC);
2855
2856 // (shl ShVal, X) | (lshr ShVal, (Width - x)) iff X < Width.
2857 // We limit this to X < Width in case the backend re-expands the
2858 // intrinsic, and has to reintroduce a shift modulo operation (InstCombine
2859 // might remove it after this fold). This still doesn't guarantee that the
2860 // final codegen will match this original pattern.
2861 if (match(R, m_OneUse(m_Sub(m_SpecificInt(Width), m_Specific(L))))) {
2862 KnownBits KnownL = computeKnownBits(L, /*Depth*/ 0, &Or);
2863 return KnownL.getMaxValue().ult(Width) ? L : nullptr;
2864 }
2865
2866 // For non-constant cases, the following patterns currently only work for
2867 // rotation patterns.
2868 // TODO: Add general funnel-shift compatible patterns.
2869 if (ShVal0 != ShVal1)
2870 return nullptr;
2871
2872 // For non-constant cases we don't support non-pow2 shift masks.
2873 // TODO: Is it worth matching urem as well?
2874 if (!isPowerOf2_32(Width))
2875 return nullptr;
2876
2877 // The shift amount may be masked with negation:
2878 // (shl ShVal, (X & (Width - 1))) | (lshr ShVal, ((-X) & (Width - 1)))
2879 Value *X;
2880 unsigned Mask = Width - 1;
2881 if (match(L, m_And(m_Value(X), m_SpecificInt(Mask))) &&
2882 match(R, m_And(m_Neg(m_Specific(X)), m_SpecificInt(Mask))))
2883 return X;
2884
2885 // (shl ShVal, X) | (lshr ShVal, ((-X) & (Width - 1)))
2886 if (match(R, m_And(m_Neg(m_Specific(L)), m_SpecificInt(Mask))))
2887 return L;
2888
2889 // Similar to above, but the shift amount may be extended after masking,
2890 // so return the extended value as the parameter for the intrinsic.
2891 if (match(L, m_ZExt(m_And(m_Value(X), m_SpecificInt(Mask)))) &&
2892 match(R,
2894 m_SpecificInt(Mask))))
2895 return L;
2896
2897 if (match(L, m_ZExt(m_And(m_Value(X), m_SpecificInt(Mask)))) &&
2899 return L;
2900
2901 return nullptr;
2902 };
2903
2904 Value *ShAmt = matchShiftAmount(ShAmt0, ShAmt1, Width);
2905 if (!ShAmt) {
2906 ShAmt = matchShiftAmount(ShAmt1, ShAmt0, Width);
2907 IsFshl = false; // Sub on SHL.
2908 }
2909 if (!ShAmt)
2910 return std::nullopt;
2911
2912 FShiftArgs = {ShVal0, ShVal1, ShAmt};
2913 } else if (isa<ZExtInst>(Or0) || isa<ZExtInst>(Or1)) {
2914 // If there are two 'or' instructions concat variables in opposite order:
2915 //
2916 // Slot1 and Slot2 are all zero bits.
2917 // | Slot1 | Low | Slot2 | High |
2918 // LowHigh = or (shl (zext Low), ZextLowShlAmt), (zext High)
2919 // | Slot2 | High | Slot1 | Low |
2920 // HighLow = or (shl (zext High), ZextHighShlAmt), (zext Low)
2921 //
2922 // the latter 'or' can be safely convert to
2923 // -> HighLow = fshl LowHigh, LowHigh, ZextHighShlAmt
2924 // if ZextLowShlAmt + ZextHighShlAmt == Width.
2925 if (!isa<ZExtInst>(Or1))
2926 std::swap(Or0, Or1);
2927
2928 Value *High, *ZextHigh, *Low;
2929 const APInt *ZextHighShlAmt;
2930 if (!match(Or0,
2931 m_OneUse(m_Shl(m_Value(ZextHigh), m_APInt(ZextHighShlAmt)))))
2932 return std::nullopt;
2933
2934 if (!match(Or1, m_ZExt(m_Value(Low))) ||
2935 !match(ZextHigh, m_ZExt(m_Value(High))))
2936 return std::nullopt;
2937
2938 unsigned HighSize = High->getType()->getScalarSizeInBits();
2939 unsigned LowSize = Low->getType()->getScalarSizeInBits();
2940 // Make sure High does not overlap with Low and most significant bits of
2941 // High aren't shifted out.
2942 if (ZextHighShlAmt->ult(LowSize) || ZextHighShlAmt->ugt(Width - HighSize))
2943 return std::nullopt;
2944
2945 for (User *U : ZextHigh->users()) {
2946 Value *X, *Y;
2947 if (!match(U, m_Or(m_Value(X), m_Value(Y))))
2948 continue;
2949
2950 if (!isa<ZExtInst>(Y))
2951 std::swap(X, Y);
2952
2953 const APInt *ZextLowShlAmt;
2954 if (!match(X, m_Shl(m_Specific(Or1), m_APInt(ZextLowShlAmt))) ||
2955 !match(Y, m_Specific(ZextHigh)) || !DT.dominates(U, &Or))
2956 continue;
2957
2958 // HighLow is good concat. If sum of two shifts amount equals to Width,
2959 // LowHigh must also be a good concat.
2960 if (*ZextLowShlAmt + *ZextHighShlAmt != Width)
2961 continue;
2962
2963 // Low must not overlap with High and most significant bits of Low must
2964 // not be shifted out.
2965 assert(ZextLowShlAmt->uge(HighSize) &&
2966 ZextLowShlAmt->ule(Width - LowSize) && "Invalid concat");
2967
2968 FShiftArgs = {U, U, ConstantInt::get(Or0->getType(), *ZextHighShlAmt)};
2969 break;
2970 }
2971 }
2972
2973 if (FShiftArgs.empty())
2974 return std::nullopt;
2975
2976 Intrinsic::ID IID = IsFshl ? Intrinsic::fshl : Intrinsic::fshr;
2977 return std::make_pair(IID, FShiftArgs);
2978}
2979
2980/// Match UB-safe variants of the funnel shift intrinsic.
2982 if (auto Opt = IC.convertOrOfShiftsToFunnelShift(Or)) {
2983 auto [IID, FShiftArgs] = *Opt;
2984 Function *F = Intrinsic::getDeclaration(Or.getModule(), IID, Or.getType());
2985 return CallInst::Create(F, FShiftArgs);
2986 }
2987
2988 return nullptr;
2989}
2990
2991/// Attempt to combine or(zext(x),shl(zext(y),bw/2) concat packing patterns.
2993 InstCombiner::BuilderTy &Builder) {
2994 assert(Or.getOpcode() == Instruction::Or && "bswap requires an 'or'");
2995 Value *Op0 = Or.getOperand(0), *Op1 = Or.getOperand(1);
2996 Type *Ty = Or.getType();
2997
2998 unsigned Width = Ty->getScalarSizeInBits();
2999 if ((Width & 1) != 0)
3000 return nullptr;
3001 unsigned HalfWidth = Width / 2;
3002
3003 // Canonicalize zext (lower half) to LHS.
3004 if (!isa<ZExtInst>(Op0))
3005 std::swap(Op0, Op1);
3006
3007 // Find lower/upper half.
3008 Value *LowerSrc, *ShlVal, *UpperSrc;
3009 const APInt *C;
3010 if (!match(Op0, m_OneUse(m_ZExt(m_Value(LowerSrc)))) ||
3011 !match(Op1, m_OneUse(m_Shl(m_Value(ShlVal), m_APInt(C)))) ||
3012 !match(ShlVal, m_OneUse(m_ZExt(m_Value(UpperSrc)))))
3013 return nullptr;
3014 if (*C != HalfWidth || LowerSrc->getType() != UpperSrc->getType() ||
3015 LowerSrc->getType()->getScalarSizeInBits() != HalfWidth)
3016 return nullptr;
3017
3018 auto ConcatIntrinsicCalls = [&](Intrinsic::ID id, Value *Lo, Value *Hi) {
3019 Value *NewLower = Builder.CreateZExt(Lo, Ty);
3020 Value *NewUpper = Builder.CreateZExt(Hi, Ty);
3021 NewUpper = Builder.CreateShl(NewUpper, HalfWidth);
3022 Value *BinOp = Builder.CreateOr(NewLower, NewUpper);
3023 Function *F = Intrinsic::getDeclaration(Or.getModule(), id, Ty);
3024 return Builder.CreateCall(F, BinOp);
3025 };
3026
3027 // BSWAP: Push the concat down, swapping the lower/upper sources.
3028 // concat(bswap(x),bswap(y)) -> bswap(concat(x,y))
3029 Value *LowerBSwap, *UpperBSwap;
3030 if (match(LowerSrc, m_BSwap(m_Value(LowerBSwap))) &&
3031 match(UpperSrc, m_BSwap(m_Value(UpperBSwap))))
3032 return ConcatIntrinsicCalls(Intrinsic::bswap, UpperBSwap, LowerBSwap);
3033
3034 // BITREVERSE: Push the concat down, swapping the lower/upper sources.
3035 // concat(bitreverse(x),bitreverse(y)) -> bitreverse(concat(x,y))
3036 Value *LowerBRev, *UpperBRev;
3037 if (match(LowerSrc, m_BitReverse(m_Value(LowerBRev))) &&
3038 match(UpperSrc, m_BitReverse(m_Value(UpperBRev))))
3039 return ConcatIntrinsicCalls(Intrinsic::bitreverse, UpperBRev, LowerBRev);
3040
3041 return nullptr;
3042}
3043
3044/// If all elements of two constant vectors are 0/-1 and inverses, return true.
3046 unsigned NumElts = cast<FixedVectorType>(C1->getType())->getNumElements();
3047 for (unsigned i = 0; i != NumElts; ++i) {
3048 Constant *EltC1 = C1->getAggregateElement(i);
3049 Constant *EltC2 = C2->getAggregateElement(i);
3050 if (!EltC1 || !EltC2)
3051 return false;
3052
3053 // One element must be all ones, and the other must be all zeros.
3054 if (!((match(EltC1, m_Zero()) && match(EltC2, m_AllOnes())) ||
3055 (match(EltC2, m_Zero()) && match(EltC1, m_AllOnes()))))
3056 return false;
3057 }
3058 return true;
3059}
3060
3061/// We have an expression of the form (A & C) | (B & D). If A is a scalar or
3062/// vector composed of all-zeros or all-ones values and is the bitwise 'not' of
3063/// B, it can be used as the condition operand of a select instruction.
3064/// We will detect (A & C) | ~(B | D) when the flag ABIsTheSame enabled.
3065Value *InstCombinerImpl::getSelectCondition(Value *A, Value *B,
3066 bool ABIsTheSame) {
3067 // We may have peeked through bitcasts in the caller.
3068 // Exit immediately if we don't have (vector) integer types.
3069 Type *Ty = A->getType();
3070 if (!Ty->isIntOrIntVectorTy() || !B->getType()->isIntOrIntVectorTy())
3071 return nullptr;
3072
3073 // If A is the 'not' operand of B and has enough signbits, we have our answer.
3074 if (ABIsTheSame ? (A == B) : match(B, m_Not(m_Specific(A)))) {
3075 // If these are scalars or vectors of i1, A can be used directly.
3076 if (Ty->isIntOrIntVectorTy(1))
3077 return A;
3078
3079 // If we look through a vector bitcast, the caller will bitcast the operands
3080 // to match the condition's number of bits (N x i1).
3081 // To make this poison-safe, disallow bitcast from wide element to narrow
3082 // element. That could allow poison in lanes where it was not present in the
3083 // original code.
3085 if (A->getType()->isIntOrIntVectorTy()) {
3086 unsigned NumSignBits = ComputeNumSignBits(A);
3087 if (NumSignBits == A->getType()->getScalarSizeInBits() &&
3088 NumSignBits <= Ty->getScalarSizeInBits())
3089 return Builder.CreateTrunc(A, CmpInst::makeCmpResultType(A->getType()));
3090 }
3091 return nullptr;
3092 }
3093
3094 // TODO: add support for sext and constant case
3095 if (ABIsTheSame)
3096 return nullptr;
3097
3098 // If both operands are constants, see if the constants are inverse bitmasks.
3099 Constant *AConst, *BConst;
3100 if (match(A, m_Constant(AConst)) && match(B, m_Constant(BConst)))
3101 if (AConst == ConstantExpr::getNot(BConst) &&
3104
3105 // Look for more complex patterns. The 'not' op may be hidden behind various
3106 // casts. Look through sexts and bitcasts to find the booleans.
3107 Value *Cond;
3108 Value *NotB;
3109 if (match(A, m_SExt(m_Value(Cond))) &&
3110 Cond->getType()->isIntOrIntVectorTy(1)) {
3111 // A = sext i1 Cond; B = sext (not (i1 Cond))
3112 if (match(B, m_SExt(m_Not(m_Specific(Cond)))))
3113 return Cond;
3114
3115 // A = sext i1 Cond; B = not ({bitcast} (sext (i1 Cond)))
3116 // TODO: The one-use checks are unnecessary or misplaced. If the caller
3117 // checked for uses on logic ops/casts, that should be enough to
3118 // make this transform worthwhile.
3119 if (match(B, m_OneUse(m_Not(m_Value(NotB))))) {
3120 NotB = peekThroughBitcast(NotB, true);
3121 if (match(NotB, m_SExt(m_Specific(Cond))))
3122 return Cond;
3123 }
3124 }
3125
3126 // All scalar (and most vector) possibilities should be handled now.
3127 // Try more matches that only apply to non-splat constant vectors.
3128 if (!Ty->isVectorTy())
3129 return nullptr;
3130
3131 // If both operands are xor'd with constants using the same sexted boolean
3132 // operand, see if the constants are inverse bitmasks.
3133 // TODO: Use ConstantExpr::getNot()?
3134 if (match(A, (m_Xor(m_SExt(m_Value(Cond)), m_Constant(AConst)))) &&
3135 match(B, (m_Xor(m_SExt(m_Specific(Cond)), m_Constant(BConst)))) &&
3136 Cond->getType()->isIntOrIntVectorTy(1) &&
3137 areInverseVectorBitmasks(AConst, BConst)) {
3139 return Builder.CreateXor(Cond, AConst);
3140 }
3141 return nullptr;
3142}
3143
3144/// We have an expression of the form (A & B) | (C & D). Try to simplify this
3145/// to "A' ? B : D", where A' is a boolean or vector of booleans.
3146/// When InvertFalseVal is set to true, we try to match the pattern
3147/// where we have peeked through a 'not' op and A and C are the same:
3148/// (A & B) | ~(A | D) --> (A & B) | (~A & ~D) --> A' ? B : ~D
3149Value *InstCombinerImpl::matchSelectFromAndOr(Value *A, Value *B, Value *C,
3150 Value *D, bool InvertFalseVal) {
3151 // The potential condition of the select may be bitcasted. In that case, look
3152 // through its bitcast and the corresponding bitcast of the 'not' condition.
3153 Type *OrigType = A->getType();
3154 A = peekThroughBitcast(A, true);
3155 C = peekThroughBitcast(C, true);
3156 if (Value *Cond = getSelectCondition(A, C, InvertFalseVal)) {
3157 // ((bc Cond) & B) | ((bc ~Cond) & D) --> bc (select Cond, (bc B), (bc D))
3158 // If this is a vector, we may need to cast to match the condition's length.
3159 // The bitcasts will either all exist or all not exist. The builder will
3160 // not create unnecessary casts if the types already match.
3161 Type *SelTy = A->getType();
3162 if (auto *VecTy = dyn_cast<VectorType>(Cond->getType())) {
3163 // For a fixed or scalable vector get N from <{vscale x} N x iM>
3164 unsigned Elts = VecTy->getElementCount().getKnownMinValue();
3165 // For a fixed or scalable vector, get the size in bits of N x iM; for a
3166 // scalar this is just M.
3167 unsigned SelEltSize = SelTy->getPrimitiveSizeInBits().getKnownMinValue();
3168 Type *EltTy = Builder.getIntNTy(SelEltSize / Elts);
3169 SelTy = VectorType::get(EltTy, VecTy->getElementCount());
3170 }
3171 Value *BitcastB = Builder.CreateBitCast(B, SelTy);
3172 if (InvertFalseVal)
3173 D = Builder.CreateNot(D);
3174 Value *BitcastD = Builder.CreateBitCast(D, SelTy);
3175 Value *Select = Builder.CreateSelect(Cond, BitcastB, BitcastD);
3176 return Builder.CreateBitCast(Select, OrigType);
3177 }
3178
3179 return nullptr;
3180}
3181
3182// (icmp eq X, C) | (icmp ult Other, (X - C)) -> (icmp ule Other, (X - (C + 1)))
3183// (icmp ne X, C) & (icmp uge Other, (X - C)) -> (icmp ugt Other, (X - (C + 1)))
3185 bool IsAnd, bool IsLogical,
3186 IRBuilderBase &Builder) {
3187 Value *LHS0 = LHS->getOperand(0);
3188 Value *RHS0 = RHS->getOperand(0);
3189 Value *RHS1 = RHS->getOperand(1);
3190
3191 ICmpInst::Predicate LPred =
3192 IsAnd ? LHS->getInversePredicate() : LHS->getPredicate();
3193 ICmpInst::Predicate RPred =
3194 IsAnd ? RHS->getInversePredicate() : RHS->getPredicate();
3195
3196 const APInt *CInt;
3197 if (LPred != ICmpInst::ICMP_EQ ||
3198 !match(LHS->getOperand(1), m_APIntAllowPoison(CInt)) ||
3199 !LHS0->getType()->isIntOrIntVectorTy() ||
3200 !(LHS->hasOneUse() || RHS->hasOneUse()))
3201 return nullptr;
3202
3203 auto MatchRHSOp = [LHS0, CInt](const Value *RHSOp) {
3204 return match(RHSOp,
3205 m_Add(m_Specific(LHS0), m_SpecificIntAllowPoison(-*CInt))) ||
3206 (CInt->isZero() && RHSOp == LHS0);
3207 };
3208
3209 Value *Other;
3210 if (RPred == ICmpInst::ICMP_ULT && MatchRHSOp(RHS1))
3211 Other = RHS0;
3212 else if (RPred == ICmpInst::ICMP_UGT && MatchRHSOp(RHS0))
3213 Other = RHS1;
3214 else
3215 return nullptr;
3216
3217 if (IsLogical)
3218 Other = Builder.CreateFreeze(Other);
3219
3220 return Builder.CreateICmp(
3222 Builder.CreateSub(LHS0, ConstantInt::get(LHS0->getType(), *CInt + 1)),
3223 Other);
3224}
3225
3226/// Fold (icmp)&(icmp) or (icmp)|(icmp) if possible.
3227/// If IsLogical is true, then the and/or is in select form and the transform
3228/// must be poison-safe.
3229Value *InstCombinerImpl::foldAndOrOfICmps(ICmpInst *LHS, ICmpInst *RHS,
3230 Instruction &I, bool IsAnd,
3231 bool IsLogical) {
3233
3234 // Fold (iszero(A & K1) | iszero(A & K2)) -> (A & (K1 | K2)) != (K1 | K2)
3235 // Fold (!iszero(A & K1) & !iszero(A & K2)) -> (A & (K1 | K2)) == (K1 | K2)
3236 // if K1 and K2 are a one-bit mask.
3237 if (Value *V = foldAndOrOfICmpsOfAndWithPow2(LHS, RHS, &I, IsAnd, IsLogical))
3238 return V;
3239
3240 ICmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
3241 Value *LHS0 = LHS->getOperand(0), *RHS0 = RHS->getOperand(0);
3242 Value *LHS1 = LHS->getOperand(1), *RHS1 = RHS->getOperand(1);
3243 const APInt *LHSC = nullptr, *RHSC = nullptr;
3244 match(LHS1, m_APInt(LHSC));
3245 match(RHS1, m_APInt(RHSC));
3246
3247 // (icmp1 A, B) | (icmp2 A, B) --> (icmp3 A, B)
3248 // (icmp1 A, B) & (icmp2 A, B) --> (icmp3 A, B)
3249 if (predicatesFoldable(PredL, PredR)) {
3250 if (LHS0 == RHS1 && LHS1 == RHS0) {
3251 PredL = ICmpInst::getSwappedPredicate(PredL);
3252 std::swap(LHS0, LHS1);
3253 }
3254 if (LHS0 == RHS0 && LHS1 == RHS1) {
3255 unsigned Code = IsAnd ? getICmpCode(PredL) & getICmpCode(PredR)
3256 : getICmpCode(PredL) | getICmpCode(PredR);
3257 bool IsSigned = LHS->isSigned() || RHS->isSigned();
3258 return getNewICmpValue(Code, IsSigned, LHS0, LHS1, Builder);
3259 }
3260 }
3261
3262 // handle (roughly):
3263 // (icmp ne (A & B), C) | (icmp ne (A & D), E)
3264 // (icmp eq (A & B), C) & (icmp eq (A & D), E)
3265 if (Value *V = foldLogOpOfMaskedICmps(LHS, RHS, IsAnd, IsLogical, Builder))
3266 return V;
3267
3268 if (Value *V =
3269 foldAndOrOfICmpEqConstantAndICmp(LHS, RHS, IsAnd, IsLogical, Builder))
3270 return V;
3271 // We can treat logical like bitwise here, because both operands are used on
3272 // the LHS, and as such poison from both will propagate.
3273 if (Value *V = foldAndOrOfICmpEqConstantAndICmp(RHS, LHS, IsAnd,
3274 /*IsLogical*/ false, Builder))
3275 return V;
3276
3277 if (Value *V =
3278 foldAndOrOfICmpsWithConstEq(LHS, RHS, IsAnd, IsLogical, Builder, Q))
3279 return V;
3280 // We can convert this case to bitwise and, because both operands are used
3281 // on the LHS, and as such poison from both will propagate.
3282 if (Value *V = foldAndOrOfICmpsWithConstEq(RHS, LHS, IsAnd,
3283 /*IsLogical*/ false, Builder, Q))
3284 return V;
3285
3286 if (Value *V = foldIsPowerOf2OrZero(LHS, RHS, IsAnd, Builder))
3287 return V;
3288 if (Value *V = foldIsPowerOf2OrZero(RHS, LHS, IsAnd, Builder))
3289 return V;
3290
3291 // TODO: One of these directions is fine with logical and/or, the other could
3292 // be supported by inserting freeze.
3293 if (!IsLogical) {
3294 // E.g. (icmp slt x, 0) | (icmp sgt x, n) --> icmp ugt x, n
3295 // E.g. (icmp sge x, 0) & (icmp slt x, n) --> icmp ult x, n
3296 if (Value *V = simplifyRangeCheck(LHS, RHS, /*Inverted=*/!IsAnd))
3297 return V;
3298
3299 // E.g. (icmp sgt x, n) | (icmp slt x, 0) --> icmp ugt x, n
3300 // E.g. (icmp slt x, n) & (icmp sge x, 0) --> icmp ult x, n
3301 if (Value *V = simplifyRangeCheck(RHS, LHS, /*Inverted=*/!IsAnd))
3302 return V;
3303 }
3304
3305 // TODO: Add conjugated or fold, check whether it is safe for logical and/or.
3306 if (IsAnd && !IsLogical)
3307 if (Value *V = foldSignedTruncationCheck(LHS, RHS, I, Builder))
3308 return V;
3309
3310 if (Value *V = foldIsPowerOf2(LHS, RHS, IsAnd, Builder))
3311 return V;
3312
3313 if (Value *V = foldPowerOf2AndShiftedMask(LHS, RHS, IsAnd, Builder))
3314 return V;
3315
3316 // TODO: Verify whether this is safe for logical and/or.
3317 if (!IsLogical) {
3318 if (Value *X = foldUnsignedUnderflowCheck(LHS, RHS, IsAnd, Q, Builder))
3319 return X;
3320 if (Value *X = foldUnsignedUnderflowCheck(RHS, LHS, IsAnd, Q, Builder))
3321 return X;
3322 }
3323
3324 if (Value *X = foldEqOfParts(LHS, RHS, IsAnd))
3325 return X;
3326
3327 // (icmp ne A, 0) | (icmp ne B, 0) --> (icmp ne (A|B), 0)
3328 // (icmp eq A, 0) & (icmp eq B, 0) --> (icmp eq (A|B), 0)
3329 // TODO: Remove this and below when foldLogOpOfMaskedICmps can handle undefs.
3330 if (!IsLogical && PredL == (IsAnd ? ICmpInst::ICMP_EQ : ICmpInst::ICMP_NE) &&
3331 PredL == PredR && match(LHS1, m_ZeroInt()) && match(RHS1, m_ZeroInt()) &&
3332 LHS0->getType() == RHS0->getType()) {
3333 Value *NewOr = Builder.CreateOr(LHS0, RHS0);
3334 return Builder.CreateICmp(PredL, NewOr,
3336 }
3337
3338 // (icmp ne A, -1) | (icmp ne B, -1) --> (icmp ne (A&B), -1)
3339 // (icmp eq A, -1) & (icmp eq B, -1) --> (icmp eq (A&B), -1)
3340 if (!IsLogical && PredL == (IsAnd ? ICmpInst::ICMP_EQ : ICmpInst::ICMP_NE) &&
3341 PredL == PredR && match(LHS1, m_AllOnes()) && match(RHS1, m_AllOnes()) &&
3342 LHS0->getType() == RHS0->getType()) {
3343 Value *NewAnd = Builder.CreateAnd(LHS0, RHS0);
3344 return Builder.CreateICmp(PredL, NewAnd,
3346 }
3347
3348 // This only handles icmp of constants: (icmp1 A, C1) | (icmp2 B, C2).
3349 if (!LHSC || !RHSC)
3350 return nullptr;
3351
3352 // (trunc x) == C1 & (and x, CA) == C2 -> (and x, CA|CMAX) == C1|C2
3353 // (trunc x) != C1 | (and x, CA) != C2 -> (and x, CA|CMAX) != C1|C2
3354 // where CMAX is the all ones value for the truncated type,
3355 // iff the lower bits of C2 and CA are zero.
3356 if (PredL == (IsAnd ? ICmpInst::ICMP_EQ : ICmpInst::ICMP_NE) &&
3357 PredL == PredR && LHS->hasOneUse() && RHS->hasOneUse()) {
3358 Value *V;
3359 const APInt *AndC, *SmallC = nullptr, *BigC = nullptr;
3360
3361 // (trunc x) == C1 & (and x, CA) == C2
3362 // (and x, CA) == C2 & (trunc x) == C1
3363 if (match(RHS0, m_Trunc(m_Value(V))) &&
3364 match(LHS0, m_And(m_Specific(V), m_APInt(AndC)))) {
3365 SmallC = RHSC;
3366 BigC = LHSC;
3367 } else if (match(LHS0, m_Trunc(m_Value(V))) &&
3368 match(RHS0, m_And(m_Specific(V), m_APInt(AndC)))) {
3369 SmallC = LHSC;
3370 BigC = RHSC;
3371 }
3372
3373 if (SmallC && BigC) {
3374 unsigned BigBitSize = BigC->getBitWidth();
3375 unsigned SmallBitSize = SmallC->getBitWidth();
3376
3377 // Check that the low bits are zero.
3378 APInt Low = APInt::getLowBitsSet(BigBitSize, SmallBitSize);
3379 if ((Low & *AndC).isZero() && (Low & *BigC).isZero()) {
3380 Value *NewAnd = Builder.CreateAnd(V, Low | *AndC);
3381 APInt N = SmallC->zext(BigBitSize) | *BigC;
3382 Value *NewVal = ConstantInt::get(NewAnd->getType(), N);
3383 return Builder.CreateICmp(PredL, NewAnd, NewVal);
3384 }
3385 }
3386 }
3387
3388 // Match naive pattern (and its inverted form) for checking if two values
3389 // share same sign. An example of the pattern:
3390 // (icmp slt (X & Y), 0) | (icmp sgt (X | Y), -1) -> (icmp sgt (X ^ Y), -1)
3391 // Inverted form (example):
3392 // (icmp slt (X | Y), 0) & (icmp sgt (X & Y), -1) -> (icmp slt (X ^ Y), 0)
3393 bool TrueIfSignedL, TrueIfSignedR;
3394 if (isSignBitCheck(PredL, *LHSC, TrueIfSignedL) &&
3395 isSignBitCheck(PredR, *RHSC, TrueIfSignedR) &&
3396 (RHS->hasOneUse() || LHS->hasOneUse())) {
3397 Value *X, *Y;
3398 if (IsAnd) {
3399 if ((TrueIfSignedL && !TrueIfSignedR &&
3400 match(LHS0, m_Or(m_Value(X), m_Value(Y))) &&
3401 match(RHS0, m_c_And(m_Specific(X), m_Specific(Y)))) ||
3402 (!TrueIfSignedL && TrueIfSignedR &&
3403 match(LHS0, m_And(m_Value(X), m_Value(Y))) &&
3404 match(RHS0, m_c_Or(m_Specific(X), m_Specific(Y))))) {
3405 Value *NewXor = Builder.CreateXor(X, Y);
3406 return Builder.CreateIsNeg(NewXor);
3407 }
3408 } else {
3409 if ((TrueIfSignedL && !TrueIfSignedR &&
3410 match(LHS0, m_And(m_Value(X), m_Value(Y))) &&
3411 match(RHS0, m_c_Or(m_Specific(X), m_Specific(Y)))) ||
3412 (!TrueIfSignedL && TrueIfSignedR &&
3413 match(LHS0, m_Or(m_Value(X), m_Value(Y))) &&
3414 match(RHS0, m_c_And(m_Specific(X), m_Specific(Y))))) {
3415 Value *NewXor = Builder.CreateXor(X, Y);
3416 return Builder.CreateIsNotNeg(NewXor);
3417 }
3418 }
3419 }
3420
3421 return foldAndOrOfICmpsUsingRanges(LHS, RHS, IsAnd);
3422}
3423
3424// FIXME: We use commutative matchers (m_c_*) for some, but not all, matches
3425// here. We should standardize that construct where it is needed or choose some
3426// other way to ensure that commutated variants of patterns are not missed.
3428 if (Value *V = simplifyOrInst(I.getOperand(0), I.getOperand(1),
3430 return replaceInstUsesWith(I, V);
3431
3433 return &I;
3434
3436 return X;
3437
3439 return Phi;
3440
3441 // See if we can simplify any instructions used by the instruction whose sole
3442 // purpose is to compute bits we don't care about.
3444 return &I;
3445
3446 // Do this before using distributive laws to catch simple and/or/not patterns.
3448 return Xor;
3449
3451 return X;
3452
3453 // (A&B)|(A&C) -> A&(B|C) etc
3455 return replaceInstUsesWith(I, V);
3456
3457 Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
3458 Type *Ty = I.getType();
3459 if (Ty->isIntOrIntVectorTy(1)) {
3460 if (auto *SI0 = dyn_cast<SelectInst>(Op0)) {
3461 if (auto *R =
3462 foldAndOrOfSelectUsingImpliedCond(Op1, *SI0, /* IsAnd */ false))
3463 return R;
3464 }
3465 if (auto *SI1 = dyn_cast<SelectInst>(Op1)) {
3466 if (auto *R =
3467 foldAndOrOfSelectUsingImpliedCond(Op0, *SI1, /* IsAnd */ false))
3468 return R;
3469 }
3470 }
3471
3472 if (Instruction *FoldedLogic = foldBinOpIntoSelectOrPhi(I))
3473 return FoldedLogic;
3474
3475 if (Instruction *BitOp = matchBSwapOrBitReverse(I, /*MatchBSwaps*/ true,
3476 /*MatchBitReversals*/ true))
3477 return BitOp;
3478
3479 if (Instruction *Funnel = matchFunnelShift(I, *this))
3480 return Funnel;
3481
3483 return replaceInstUsesWith(I, Concat);
3484
3486 return R;
3487
3489 return R;
3490
3491 Value *X, *Y;
3492 const APInt *CV;
3493 if (match(&I, m_c_Or(m_OneUse(m_Xor(m_Value(X), m_APInt(CV))), m_Value(Y))) &&
3494 !CV->isAllOnes() && MaskedValueIsZero(Y, *CV, 0, &I)) {
3495 // (X ^ C) | Y -> (X | Y) ^ C iff Y & C == 0
3496 // The check for a 'not' op is for efficiency (if Y is known zero --> ~X).
3497 Value *Or = Builder.CreateOr(X, Y);
3498 return BinaryOperator::CreateXor(Or, ConstantInt::get(Ty, *CV));
3499 }
3500
3501 // If the operands have no common bits set:
3502 // or (mul X, Y), X --> add (mul X, Y), X --> mul X, (Y + 1)
3504 m_Deferred(X)))) {
3505 Value *IncrementY = Builder.CreateAdd(Y, ConstantInt::get(Ty, 1));
3506 return BinaryOperator::CreateMul(X, IncrementY);
3507 }
3508
3509 // (A & C) | (B & D)
3510 Value *A, *B, *C, *D;
3511 if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
3512 match(Op1, m_And(m_Value(B), m_Value(D)))) {
3513
3514 // (A & C0) | (B & C1)
3515 const APInt *C0, *C1;
3516 if (match(C, m_APInt(C0)) && match(D, m_APInt(C1))) {
3517 Value *X;
3518 if (*C0 == ~*C1) {
3519 // ((X | B) & MaskC) | (B & ~MaskC) -> (X & MaskC) | B
3520 if (match(A, m_c_Or(m_Value(X), m_Specific(B))))
3521 return BinaryOperator::CreateOr(Builder.CreateAnd(X, *C0), B);
3522 // (A & MaskC) | ((X | A) & ~MaskC) -> (X & ~MaskC) | A
3523 if (match(B, m_c_Or(m_Specific(A), m_Value(X))))
3524 return BinaryOperator::CreateOr(Builder.CreateAnd(X, *C1), A);
3525
3526 // ((X ^ B) & MaskC) | (B & ~MaskC) -> (X & MaskC) ^ B
3527 if (match(A, m_c_Xor(m_Value(X), m_Specific(B))))
3528 return BinaryOperator::CreateXor(Builder.CreateAnd(X, *C0), B);
3529 // (A & MaskC) | ((X ^ A) & ~MaskC) -> (X & ~MaskC) ^ A
3530 if (match(B, m_c_Xor(m_Specific(A), m_Value(X))))
3531 return BinaryOperator::CreateXor(Builder.CreateAnd(X, *C1), A);
3532 }
3533
3534 if ((*C0 & *C1).isZero()) {
3535 // ((X | B) & C0) | (B & C1) --> (X | B) & (C0 | C1)
3536 // iff (C0 & C1) == 0 and (X & ~C0) == 0
3537 if (match(A, m_c_Or(m_Value(X), m_Specific(B))) &&
3538 MaskedValueIsZero(X, ~*C0, 0, &I)) {
3539 Constant *C01 = ConstantInt::get(Ty, *C0 | *C1);
3540 return BinaryOperator::CreateAnd(A, C01);
3541 }
3542 // (A & C0) | ((X | A) & C1) --> (X | A) & (C0 | C1)
3543 // iff (C0 & C1) == 0 and (X & ~C1) == 0
3544 if (match(B, m_c_Or(m_Value(X), m_Specific(A))) &&
3545 MaskedValueIsZero(X, ~*C1, 0, &I)) {
3546 Constant *C01 = ConstantInt::get(Ty, *C0 | *C1);
3547 return BinaryOperator::CreateAnd(B, C01);
3548 }
3549 // ((X | C2) & C0) | ((X | C3) & C1) --> (X | C2 | C3) & (C0 | C1)
3550 // iff (C0 & C1) == 0 and (C2 & ~C0) == 0 and (C3 & ~C1) == 0.
3551 const APInt *C2, *C3;
3552 if (match(A, m_Or(m_Value(X), m_APInt(C2))) &&
3553 match(B, m_Or(m_Specific(X), m_APInt(C3))) &&
3554 (*C2 & ~*C0).isZero() && (*C3 & ~*C1).isZero()) {
3555 Value *Or = Builder.CreateOr(X, *C2 | *C3, "bitfield");
3556 Constant *C01 = ConstantInt::get(Ty, *C0 | *C1);
3557 return BinaryOperator::CreateAnd(Or, C01);
3558 }
3559 }
3560 }
3561
3562 // Don't try to form a select if it's unlikely that we'll get rid of at
3563 // least one of the operands. A select is generally more expensive than the
3564 // 'or' that it is replacing.
3565 if (Op0->hasOneUse() || Op1->hasOneUse()) {
3566 // (Cond & C) | (~Cond & D) -> Cond ? C : D, and commuted variants.
3567 if (Value *V = matchSelectFromAndOr(A, C, B, D))
3568 return replaceInstUsesWith(I, V);
3569 if (Value *V = matchSelectFromAndOr(A, C, D, B))
3570 return replaceInstUsesWith(I, V);
3571 if (Value *V = matchSelectFromAndOr(C, A, B, D))
3572 return replaceInstUsesWith(I, V);
3573 if (Value *V = matchSelectFromAndOr(C, A, D, B))
3574 return replaceInstUsesWith(I, V);
3575 if (Value *V = matchSelectFromAndOr(B, D, A, C))
3576 return replaceInstUsesWith(I, V);
3577 if (Value *V = matchSelectFromAndOr(B, D, C, A))
3578 return replaceInstUsesWith(I, V);
3579 if (Value *V = matchSelectFromAndOr(D, B, A, C))
3580 return replaceInstUsesWith(I, V);
3581 if (Value *V = matchSelectFromAndOr(D, B, C, A))
3582 return replaceInstUsesWith(I, V);
3583 }
3584 }
3585
3586 if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
3587 match(Op1, m_Not(m_Or(m_Value(B), m_Value(D)))) &&
3588 (Op0->hasOneUse() || Op1->hasOneUse())) {
3589 // (Cond & C) | ~(Cond | D) -> Cond ? C : ~D
3590 if (Value *V = matchSelectFromAndOr(A, C, B, D, true))
3591 return replaceInstUsesWith(I, V);
3592 if (Value *V = matchSelectFromAndOr(A, C, D, B, true))
3593 return replaceInstUsesWith(I, V);
3594 if (Value *V = matchSelectFromAndOr(C, A, B, D, true))
3595 return replaceInstUsesWith(I, V);
3596 if (Value *V = matchSelectFromAndOr(C, A, D, B, true))
3597 return replaceInstUsesWith(I, V);
3598 }
3599
3600 // (A ^ B) | ((B ^ C) ^ A) -> (A ^ B) | C
3601 if (match(Op0, m_Xor(m_Value(A), m_Value(B))))
3602 if (match(Op1,
3605 return BinaryOperator::CreateOr(Op0, C);
3606
3607 // ((B ^ C) ^ A) | (A ^ B) -> (A ^ B) | C
3608 if (match(Op1, m_Xor(m_Value(A), m_Value(B))))
3609 if (match(Op0,
3612 return BinaryOperator::CreateOr(Op1, C);
3613
3614 if (Instruction *DeMorgan = matchDeMorgansLaws(I, *this))
3615 return DeMorgan;
3616
3617 // Canonicalize xor to the RHS.
3618 bool SwappedForXor = false;
3619 if (match(Op0, m_Xor(m_Value(), m_Value()))) {
3620 std::swap(Op0, Op1);
3621 SwappedForXor = true;
3622 }
3623
3624 if (match(Op1, m_Xor(m_Value(A), m_Value(B)))) {
3625 // (A | ?) | (A ^ B) --> (A | ?) | B
3626 // (B | ?) | (A ^ B) --> (B | ?) | A
3627 if (match(Op0, m_c_Or(m_Specific(A), m_Value())))
3628 return BinaryOperator::CreateOr(Op0, B);
3629 if (match(Op0, m_c_Or(m_Specific(B), m_Value())))
3630 return BinaryOperator::CreateOr(Op0, A);
3631
3632 // (A & B) | (A ^ B) --> A | B
3633 // (B & A) | (A ^ B) --> A | B
3634 if (match(Op0, m_And(m_Specific(A), m_Specific(B))) ||
3635 match(Op0, m_And(m_Specific(B), m_Specific(A))))
3636 return BinaryOperator::CreateOr(A, B);
3637
3638 // ~A | (A ^ B) --> ~(A & B)
3639 // ~B | (A ^ B) --> ~(A & B)
3640 // The swap above should always make Op0 the 'not'.
3641 if ((Op0->hasOneUse() || Op1->hasOneUse()) &&
3642 (match(Op0, m_Not(m_Specific(A))) || match(Op0, m_Not(m_Specific(B)))))
3644
3645 // Same as above, but peek through an 'and' to the common operand:
3646 // ~(A & ?) | (A ^ B) --> ~((A & ?) & B)
3647 // ~(B & ?) | (A ^ B) --> ~((B & ?) & A)
3649 if ((Op0->hasOneUse() || Op1->hasOneUse()) &&
3651 m_c_And(m_Specific(A), m_Value())))))
3653 if ((Op0->hasOneUse() || Op1->hasOneUse()) &&
3655 m_c_And(m_Specific(B), m_Value())))))
3657
3658 // (~A | C) | (A ^ B) --> ~(A & B) | C
3659 // (~B | C) | (A ^ B) --> ~(A & B) | C
3660 if (Op0->hasOneUse() && Op1->hasOneUse() &&
3661 (match(Op0, m_c_Or(m_Not(m_Specific(A)), m_Value(C))) ||
3662 match(Op0, m_c_Or(m_Not(m_Specific(B)), m_Value(C))))) {
3663 Value *Nand = Builder.CreateNot(Builder.CreateAnd(A, B), "nand");
3664 return BinaryOperator::CreateOr(Nand, C);
3665 }
3666 }
3667
3668 if (SwappedForXor)
3669 std::swap(Op0, Op1);
3670
3671 {
3672 ICmpInst *LHS = dyn_cast<ICmpInst>(Op0);
3673 ICmpInst *RHS = dyn_cast<ICmpInst>(Op1);
3674 if (LHS && RHS)
3675 if (Value *Res = foldAndOrOfICmps(LHS, RHS, I, /* IsAnd */ false))
3676 return replaceInstUsesWith(I, Res);
3677
3678 // TODO: Make this recursive; it's a little tricky because an arbitrary
3679 // number of 'or' instructions might have to be created.
3680 Value *X, *Y;
3681 if (LHS && match(Op1, m_OneUse(m_LogicalOr(m_Value(X), m_Value(Y))))) {
3682 bool IsLogical = isa<SelectInst>(Op1);
3683 // LHS | (X || Y) --> (LHS || X) || Y
3684 if (auto *Cmp = dyn_cast<ICmpInst>(X))
3685 if (Value *Res =
3686 foldAndOrOfICmps(LHS, Cmp, I, /* IsAnd */ false, IsLogical))
3687 return replaceInstUsesWith(I, IsLogical
3688 ? Builder.CreateLogicalOr(Res, Y)
3689 : Builder.CreateOr(Res, Y));
3690 // LHS | (X || Y) --> X || (LHS | Y)
3691 if (auto *Cmp = dyn_cast<ICmpInst>(Y))
3692 if (Value *Res = foldAndOrOfICmps(LHS, Cmp, I, /* IsAnd */ false,
3693 /* IsLogical */ false))
3694 return replaceInstUsesWith(I, IsLogical
3695 ? Builder.CreateLogicalOr(X, Res)
3696 : Builder.CreateOr(X, Res));
3697 }
3698 if (RHS && match(Op0, m_OneUse(m_LogicalOr(m_Value(X), m_Value(Y))))) {
3699 bool IsLogical = isa<SelectInst>(Op0);
3700 // (X || Y) | RHS --> (X || RHS) || Y
3701 if (auto *Cmp = dyn_cast<ICmpInst>(X))
3702 if (Value *Res =
3703 foldAndOrOfICmps(Cmp, RHS, I, /* IsAnd */ false, IsLogical))
3704 return replaceInstUsesWith(I, IsLogical
3705 ? Builder.CreateLogicalOr(Res, Y)
3706 : Builder.CreateOr(Res, Y));
3707 // (X || Y) | RHS --> X || (Y | RHS)
3708 if (auto *Cmp = dyn_cast<ICmpInst>(Y))
3709 if (Value *Res = foldAndOrOfICmps(Cmp, RHS, I, /* IsAnd */ false,
3710 /* IsLogical */ false))
3711 return replaceInstUsesWith(I, IsLogical
3712 ? Builder.CreateLogicalOr(X, Res)
3713 : Builder.CreateOr(X, Res));
3714 }
3715 }
3716
3717 if (FCmpInst *LHS = dyn_cast<FCmpInst>(I.getOperand(0)))
3718 if (FCmpInst *RHS = dyn_cast<FCmpInst>(I.getOperand(1)))
3719 if (Value *Res = foldLogicOfFCmps(LHS, RHS, /*IsAnd*/ false))
3720 return replaceInstUsesWith(I, Res);
3721
3722 if (Instruction *FoldedFCmps = reassociateFCmps(I, Builder))
3723 return FoldedFCmps;
3724
3725 if (Instruction *CastedOr = foldCastedBitwiseLogic(I))
3726 return CastedOr;
3727
3728 if (Instruction *Sel = foldBinopOfSextBoolToSelect(I))
3729 return Sel;
3730
3731 // or(sext(A), B) / or(B, sext(A)) --> A ? -1 : B, where A is i1 or <N x i1>.
3732 // TODO: Move this into foldBinopOfSextBoolToSelect as a more generalized fold
3733 // with binop identity constant. But creating a select with non-constant
3734 // arm may not be reversible due to poison semantics. Is that a good
3735 // canonicalization?
3736 if (match(&I, m_c_Or(m_OneUse(m_SExt(m_Value(A))), m_Value(B))) &&
3737 A->getType()->isIntOrIntVectorTy(1))
3739
3740 // Note: If we've gotten to the point of visiting the outer OR, then the
3741 // inner one couldn't be simplified. If it was a constant, then it won't
3742 // be simplified by a later pass either, so we try swapping the inner/outer
3743 // ORs in the hopes that we'll be able to simplify it this way.
3744 // (X|C) | V --> (X|V) | C
3745 ConstantInt *CI;
3746 if (Op0->hasOneUse() && !match(Op1, m_ConstantInt()) &&
3747 match(Op0, m_Or(m_Value(A), m_ConstantInt(CI)))) {
3748 Value *Inner = Builder.CreateOr(A, Op1);
3749 Inner->takeName(Op0);
3750 return BinaryOperator::CreateOr(Inner, CI);
3751 }
3752
3753 // Change (or (bool?A:B),(bool?C:D)) --> (bool?(or A,C):(or B,D))
3754 // Since this OR statement hasn't been optimized further yet, we hope
3755 // that this transformation will allow the new ORs to be optimized.
3756 {
3757 Value *X = nullptr, *Y = nullptr;
3758 if (Op0->hasOneUse() && Op1->hasOneUse() &&
3759 match(Op0, m_Select(m_Value(X), m_Value(A), m_Value(B))) &&
3760 match(Op1, m_Select(m_Value(Y), m_Value(C), m_Value(D))) && X == Y) {
3761 Value *orTrue = Builder.CreateOr(A, C);
3762 Value *orFalse = Builder.CreateOr(B, D);
3763 return SelectInst::Create(X, orTrue, orFalse);
3764 }
3765 }
3766
3767 // or(ashr(subNSW(Y, X), ScalarSizeInBits(Y) - 1), X) --> X s> Y ? -1 : X.
3768 {
3769 Value *X, *Y;
3773 m_Deferred(X)))) {
3774 Value *NewICmpInst = Builder.CreateICmpSGT(X, Y);
3776 return SelectInst::Create(NewICmpInst, AllOnes, X);
3777 }
3778 }
3779
3780 {
3781 // ((A & B) ^ A) | ((A & B) ^ B) -> A ^ B
3782 // (A ^ (A & B)) | (B ^ (A & B)) -> A ^ B
3783 // ((A & B) ^ B) | ((A & B) ^ A) -> A ^ B
3784 // (B ^ (A & B)) | (A ^ (A & B)) -> A ^ B
3785 const auto TryXorOpt = [&](Value *Lhs, Value *Rhs) -> Instruction * {
3786 if (match(Lhs, m_c_Xor(m_And(m_Value(A), m_Value(B)), m_Deferred(A))) &&
3787 match(Rhs,
3789 return BinaryOperator::CreateXor(A, B);
3790 }
3791 return nullptr;
3792 };
3793
3794 if (Instruction *Result = TryXorOpt(Op0, Op1))
3795 return Result;
3796 if (Instruction *Result = TryXorOpt(Op1, Op0))
3797 return Result;
3798 }
3799
3800 if (Instruction *V =
3802 return V;
3803
3804 CmpInst::Predicate Pred;
3805 Value *Mul, *Ov, *MulIsNotZero, *UMulWithOv;
3806 // Check if the OR weakens the overflow condition for umul.with.overflow by
3807 // treating any non-zero result as overflow. In that case, we overflow if both
3808 // umul.with.overflow operands are != 0, as in that case the result can only
3809 // be 0, iff the multiplication overflows.
3810 if (match(&I,
3811 m_c_Or(m_CombineAnd(m_ExtractValue<1>(m_Value(UMulWithOv)),
3812 m_Value(Ov)),
3813 m_CombineAnd(m_ICmp(Pred,
3814 m_CombineAnd(m_ExtractValue<0>(
3815 m_Deferred(UMulWithOv)),
3816 m_Value(Mul)),
3817 m_ZeroInt()),
3818 m_Value(MulIsNotZero)))) &&
3819 (Ov->hasOneUse() || (MulIsNotZero->hasOneUse() && Mul->hasOneUse())) &&
3820 Pred == CmpInst::ICMP_NE) {
3821 Value *A, *B;
3822 if (match(UMulWithOv, m_Intrinsic<Intrinsic::umul_with_overflow>(
3823 m_Value(A), m_Value(B)))) {
3824 Value *NotNullA = Builder.CreateIsNotNull(A);
3825 Value *NotNullB = Builder.CreateIsNotNull(B);
3826 return BinaryOperator::CreateAnd(NotNullA, NotNullB);
3827 }
3828 }
3829
3830 /// Res, Overflow = xxx_with_overflow X, C1
3831 /// Try to canonicalize the pattern "Overflow | icmp pred Res, C2" into
3832 /// "Overflow | icmp pred X, C2 +/- C1".
3833 const WithOverflowInst *WO;
3834 const Value *WOV;
3835 const APInt *C1, *C2;
3836 if (match(&I, m_c_Or(m_CombineAnd(m_ExtractValue<1>(m_CombineAnd(
3837 m_WithOverflowInst(WO), m_Value(WOV))),
3838 m_Value(Ov)),
3839 m_OneUse(m_ICmp(Pred, m_ExtractValue<0>(m_Deferred(WOV)),
3840 m_APInt(C2))))) &&
3841 (WO->getBinaryOp() == Instruction::Add ||
3842 WO->getBinaryOp() == Instruction::Sub) &&
3843 (ICmpInst::isEquality(Pred) ||
3844 WO->isSigned() == ICmpInst::isSigned(Pred)) &&
3845