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llvm / llvm-project / 9a4320adb13b032a035f7c2ca5516202c4036d5c / . / llvm / lib / Transforms / InstCombine / InstCombineAndOrXor.cpp
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//===- InstCombineAndOrXor.cpp --------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the visitAnd, visitOr, and visitXor functions.
//
//===----------------------------------------------------------------------===//
#include "InstCombineInternal.h"
#include "llvm/Analysis/CmpInstAnalysis.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/IR/ConstantRange.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/Transforms/InstCombine/InstCombiner.h"
#include "llvm/Transforms/Utils/Local.h"
using namespace llvm;
using namespace PatternMatch;
#define DEBUG_TYPE "instcombine"
/// This is the complement of getICmpCode, which turns an opcode and two
/// operands into either a constant true or false, or a brand new ICmp
/// instruction. The sign is passed in to determine which kind of predicate to
/// use in the new icmp instruction.
static Value *getNewICmpValue(unsigned Code, bool Sign, Value *LHS, Value *RHS,
InstCombiner::BuilderTy &Builder) {
ICmpInst::Predicate NewPred;
if (Constant *TorF = getPredForICmpCode(Code, Sign, LHS->getType(), NewPred))
return TorF;
return Builder.CreateICmp(NewPred, LHS, RHS);
}
/// This is the complement of getFCmpCode, which turns an opcode and two
/// operands into either a FCmp instruction, or a true/false constant.
static Value *getFCmpValue(unsigned Code, Value *LHS, Value *RHS,
InstCombiner::BuilderTy &Builder, FMFSource FMF) {
FCmpInst::Predicate NewPred;
if (Constant *TorF = getPredForFCmpCode(Code, LHS->getType(), NewPred))
return TorF;
return Builder.CreateFCmpFMF(NewPred, LHS, RHS, FMF);
}
/// Emit a computation of: (V >= Lo && V < Hi) if Inside is true, otherwise
/// (V < Lo || V >= Hi). This method expects that Lo < Hi. IsSigned indicates
/// whether to treat V, Lo, and Hi as signed or not.
Value *InstCombinerImpl::insertRangeTest(Value *V, const APInt &Lo,
const APInt &Hi, bool isSigned,
bool Inside) {
assert((isSigned ? Lo.slt(Hi) : Lo.ult(Hi)) &&
"Lo is not < Hi in range emission code!");
Type *Ty = V->getType();
// V >= Min && V < Hi --> V < Hi
// V < Min || V >= Hi --> V >= Hi
ICmpInst::Predicate Pred = Inside ? ICmpInst::ICMP_ULT : ICmpInst::ICMP_UGE;
if (isSigned ? Lo.isMinSignedValue() : Lo.isMinValue()) {
Pred = isSigned ? ICmpInst::getSignedPredicate(Pred) : Pred;
return Builder.CreateICmp(Pred, V, ConstantInt::get(Ty, Hi));
}
// V >= Lo && V < Hi --> V - Lo u< Hi - Lo
// V < Lo || V >= Hi --> V - Lo u>= Hi - Lo
Value *VMinusLo =
Builder.CreateSub(V, ConstantInt::get(Ty, Lo), V->getName() + ".off");
Constant *HiMinusLo = ConstantInt::get(Ty, Hi - Lo);
return Builder.CreateICmp(Pred, VMinusLo, HiMinusLo);
}
/// Classify (icmp eq (A & B), C) and (icmp ne (A & B), C) as matching patterns
/// that can be simplified.
/// One of A and B is considered the mask. The other is the value. This is
/// described as the "AMask" or "BMask" part of the enum. If the enum contains
/// only "Mask", then both A and B can be considered masks. If A is the mask,
/// then it was proven that (A & C) == C. This is trivial if C == A or C == 0.
/// If both A and C are constants, this proof is also easy.
/// For the following explanations, we assume that A is the mask.
///
/// "AllOnes" declares that the comparison is true only if (A & B) == A or all
/// bits of A are set in B.
/// Example: (icmp eq (A & 3), 3) -> AMask_AllOnes
///
/// "AllZeros" declares that the comparison is true only if (A & B) == 0 or all
/// bits of A are cleared in B.
/// Example: (icmp eq (A & 3), 0) -> Mask_AllZeroes
///
/// "Mixed" declares that (A & B) == C and C might or might not contain any
/// number of one bits and zero bits.
/// Example: (icmp eq (A & 3), 1) -> AMask_Mixed
///
/// "Not" means that in above descriptions "==" should be replaced by "!=".
/// Example: (icmp ne (A & 3), 3) -> AMask_NotAllOnes
///
/// If the mask A contains a single bit, then the following is equivalent:
/// (icmp eq (A & B), A) equals (icmp ne (A & B), 0)
/// (icmp ne (A & B), A) equals (icmp eq (A & B), 0)
enum MaskedICmpType {
AMask_AllOnes = 1,
AMask_NotAllOnes = 2,
BMask_AllOnes = 4,
BMask_NotAllOnes = 8,
Mask_AllZeros = 16,
Mask_NotAllZeros = 32,
AMask_Mixed = 64,
AMask_NotMixed = 128,
BMask_Mixed = 256,
BMask_NotMixed = 512
};
/// Return the set of patterns (from MaskedICmpType) that (icmp SCC (A & B), C)
/// satisfies.
static unsigned getMaskedICmpType(Value *A, Value *B, Value *C,
ICmpInst::Predicate Pred) {
const APInt *ConstA = nullptr, *ConstB = nullptr, *ConstC = nullptr;
match(A, m_APInt(ConstA));
match(B, m_APInt(ConstB));
match(C, m_APInt(ConstC));
bool IsEq = (Pred == ICmpInst::ICMP_EQ);
bool IsAPow2 = ConstA && ConstA->isPowerOf2();
bool IsBPow2 = ConstB && ConstB->isPowerOf2();
unsigned MaskVal = 0;
if (ConstC && ConstC->isZero()) {
// if C is zero, then both A and B qualify as mask
MaskVal |= (IsEq ? (Mask_AllZeros | AMask_Mixed | BMask_Mixed)
: (Mask_NotAllZeros | AMask_NotMixed | BMask_NotMixed));
if (IsAPow2)
MaskVal |= (IsEq ? (AMask_NotAllOnes | AMask_NotMixed)
: (AMask_AllOnes | AMask_Mixed));
if (IsBPow2)
MaskVal |= (IsEq ? (BMask_NotAllOnes | BMask_NotMixed)
: (BMask_AllOnes | BMask_Mixed));
return MaskVal;
}
if (A == C) {
MaskVal |= (IsEq ? (AMask_AllOnes | AMask_Mixed)
: (AMask_NotAllOnes | AMask_NotMixed));
if (IsAPow2)
MaskVal |= (IsEq ? (Mask_NotAllZeros | AMask_NotMixed)
: (Mask_AllZeros | AMask_Mixed));
} else if (ConstA && ConstC && ConstC->isSubsetOf(*ConstA)) {
MaskVal |= (IsEq ? AMask_Mixed : AMask_NotMixed);
}
if (B == C) {
MaskVal |= (IsEq ? (BMask_AllOnes | BMask_Mixed)
: (BMask_NotAllOnes | BMask_NotMixed));
if (IsBPow2)
MaskVal |= (IsEq ? (Mask_NotAllZeros | BMask_NotMixed)
: (Mask_AllZeros | BMask_Mixed));
} else if (ConstB && ConstC && ConstC->isSubsetOf(*ConstB)) {
MaskVal |= (IsEq ? BMask_Mixed : BMask_NotMixed);
}
return MaskVal;
}
/// Convert an analysis of a masked ICmp into its equivalent if all boolean
/// operations had the opposite sense. Since each "NotXXX" flag (recording !=)
/// is adjacent to the corresponding normal flag (recording ==), this just
/// involves swapping those bits over.
static unsigned conjugateICmpMask(unsigned Mask) {
unsigned NewMask;
NewMask = (Mask & (AMask_AllOnes | BMask_AllOnes | Mask_AllZeros |
AMask_Mixed | BMask_Mixed))
<< 1;
NewMask |= (Mask & (AMask_NotAllOnes | BMask_NotAllOnes | Mask_NotAllZeros |
AMask_NotMixed | BMask_NotMixed))
>> 1;
return NewMask;
}
// Adapts the external decomposeBitTestICmp for local use.
static bool decomposeBitTestICmp(Value *Cond, CmpInst::Predicate &Pred,
Value *&X, Value *&Y, Value *&Z) {
auto Res = llvm::decomposeBitTest(Cond, /*LookThroughTrunc=*/true,
/*AllowNonZeroC=*/true);
if (!Res)
return false;
Pred = Res->Pred;
X = Res->X;
Y = ConstantInt::get(X->getType(), Res->Mask);
Z = ConstantInt::get(X->getType(), Res->C);
return true;
}
/// Handle (icmp(A & B) ==/!= C) &/| (icmp(A & D) ==/!= E).
/// Return the pattern classes (from MaskedICmpType) for the left hand side and
/// the right hand side as a pair.
/// LHS and RHS are the left hand side and the right hand side ICmps and PredL
/// and PredR are their predicates, respectively.
static std::optional<std::pair<unsigned, unsigned>>
getMaskedTypeForICmpPair(Value *&A, Value *&B, Value *&C, Value *&D, Value *&E,
Value *LHS, Value *RHS, ICmpInst::Predicate &PredL,
ICmpInst::Predicate &PredR) {
// Here comes the tricky part:
// LHS might be of the form L11 & L12 == X, X == L21 & L22,
// and L11 & L12 == L21 & L22. The same goes for RHS.
// Now we must find those components L** and R**, that are equal, so
// that we can extract the parameters A, B, C, D, and E for the canonical
// above.
// Check whether the icmp can be decomposed into a bit test.
Value *L1, *L11, *L12, *L2, *L21, *L22;
if (decomposeBitTestICmp(LHS, PredL, L11, L12, L2)) {
L21 = L22 = L1 = nullptr;
} else {
auto *LHSCMP = dyn_cast<ICmpInst>(LHS);
if (!LHSCMP)
return std::nullopt;
// Don't allow pointers. Splat vectors are fine.
if (!LHSCMP->getOperand(0)->getType()->isIntOrIntVectorTy())
return std::nullopt;
PredL = LHSCMP->getPredicate();
L1 = LHSCMP->getOperand(0);
L2 = LHSCMP->getOperand(1);
// Look for ANDs in the LHS icmp.
if (!match(L1, m_And(m_Value(L11), m_Value(L12)))) {
// Any icmp can be viewed as being trivially masked; if it allows us to
// remove one, it's worth it.
L11 = L1;
L12 = Constant::getAllOnesValue(L1->getType());
}
if (!match(L2, m_And(m_Value(L21), m_Value(L22)))) {
L21 = L2;
L22 = Constant::getAllOnesValue(L2->getType());
}
}
// Bail if LHS was a icmp that can't be decomposed into an equality.
if (!ICmpInst::isEquality(PredL))
return std::nullopt;
Value *R11, *R12, *R2;
if (decomposeBitTestICmp(RHS, PredR, R11, R12, R2)) {
if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
A = R11;
D = R12;
} else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
A = R12;
D = R11;
} else {
return std::nullopt;
}
E = R2;
} else {
auto *RHSCMP = dyn_cast<ICmpInst>(RHS);
if (!RHSCMP)
return std::nullopt;
// Don't allow pointers. Splat vectors are fine.
if (!RHSCMP->getOperand(0)->getType()->isIntOrIntVectorTy())
return std::nullopt;
PredR = RHSCMP->getPredicate();
Value *R1 = RHSCMP->getOperand(0);
R2 = RHSCMP->getOperand(1);
bool Ok = false;
if (!match(R1, m_And(m_Value(R11), m_Value(R12)))) {
// As before, model no mask as a trivial mask if it'll let us do an
// optimization.
R11 = R1;
R12 = Constant::getAllOnesValue(R1->getType());
}
if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
A = R11;
D = R12;
E = R2;
Ok = true;
} else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
A = R12;
D = R11;
E = R2;
Ok = true;
}
// Avoid matching against the -1 value we created for unmasked operand.
if (Ok && match(A, m_AllOnes()))
Ok = false;
// Look for ANDs on the right side of the RHS icmp.
if (!Ok) {
if (!match(R2, m_And(m_Value(R11), m_Value(R12)))) {
R11 = R2;
R12 = Constant::getAllOnesValue(R2->getType());
}
if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
A = R11;
D = R12;
E = R1;
} else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
A = R12;
D = R11;
E = R1;
} else {
return std::nullopt;
}
}
}
// Bail if RHS was a icmp that can't be decomposed into an equality.
if (!ICmpInst::isEquality(PredR))
return std::nullopt;
if (L11 == A) {
B = L12;
C = L2;
} else if (L12 == A) {
B = L11;
C = L2;
} else if (L21 == A) {
B = L22;
C = L1;
} else if (L22 == A) {
B = L21;
C = L1;
}
unsigned LeftType = getMaskedICmpType(A, B, C, PredL);
unsigned RightType = getMaskedICmpType(A, D, E, PredR);
return std::optional<std::pair<unsigned, unsigned>>(
std::make_pair(LeftType, RightType));
}
/// Try to fold (icmp(A & B) ==/!= C) &/| (icmp(A & D) ==/!= E) into a single
/// (icmp(A & X) ==/!= Y), where the left-hand side is of type Mask_NotAllZeros
/// and the right hand side is of type BMask_Mixed. For example,
/// (icmp (A & 12) != 0) & (icmp (A & 15) == 8) -> (icmp (A & 15) == 8).
/// Also used for logical and/or, must be poison safe.
static Value *foldLogOpOfMaskedICmps_NotAllZeros_BMask_Mixed(
Value *LHS, Value *RHS, bool IsAnd, Value *A, Value *B, Value *D, Value *E,
ICmpInst::Predicate PredL, ICmpInst::Predicate PredR,
InstCombiner::BuilderTy &Builder) {
// We are given the canonical form:
// (icmp ne (A & B), 0) & (icmp eq (A & D), E).
// where D & E == E.
//
// If IsAnd is false, we get it in negated form:
// (icmp eq (A & B), 0) | (icmp ne (A & D), E) ->
// !((icmp ne (A & B), 0) & (icmp eq (A & D), E)).
//
// We currently handle the case of B, C, D, E are constant.
//
const APInt *BCst, *DCst, *OrigECst;
if (!match(B, m_APInt(BCst)) || !match(D, m_APInt(DCst)) ||
!match(E, m_APInt(OrigECst)))
return nullptr;
ICmpInst::Predicate NewCC = IsAnd ? ICmpInst::ICMP_EQ : ICmpInst::ICMP_NE;
// Update E to the canonical form when D is a power of two and RHS is
// canonicalized as,
// (icmp ne (A & D), 0) -> (icmp eq (A & D), D) or
// (icmp ne (A & D), D) -> (icmp eq (A & D), 0).
APInt ECst = *OrigECst;
if (PredR != NewCC)
ECst ^= *DCst;
// If B or D is zero, skip because if LHS or RHS can be trivially folded by
// other folding rules and this pattern won't apply any more.
if (*BCst == 0 || *DCst == 0)
return nullptr;
// If B and D don't intersect, ie. (B & D) == 0, try to fold isNaN idiom:
// (icmp ne (A & FractionBits), 0) & (icmp eq (A & ExpBits), ExpBits)
// -> isNaN(A)
// Otherwise, we cannot deduce anything from it.
if (!BCst->intersects(*DCst)) {
Value *Src;
if (*DCst == ECst && match(A, m_ElementWiseBitCast(m_Value(Src))) &&
!Builder.GetInsertBlock()->getParent()->hasFnAttribute(
Attribute::StrictFP)) {
Type *Ty = Src->getType()->getScalarType();
if (!Ty->isIEEELikeFPTy())
return nullptr;
APInt ExpBits = APFloat::getInf(Ty->getFltSemantics()).bitcastToAPInt();
if (ECst != ExpBits)
return nullptr;
APInt FractionBits = ~ExpBits;
FractionBits.clearSignBit();
if (*BCst != FractionBits)
return nullptr;
return Builder.CreateFCmp(IsAnd ? FCmpInst::FCMP_UNO : FCmpInst::FCMP_ORD,
Src, ConstantFP::getZero(Src->getType()));
}
return nullptr;
}
// If the following two conditions are met:
//
// 1. mask B covers only a single bit that's not covered by mask D, that is,
// (B & (B ^ D)) is a power of 2 (in other words, B minus the intersection of
// B and D has only one bit set) and,
//
// 2. RHS (and E) indicates that the rest of B's bits are zero (in other
// words, the intersection of B and D is zero), that is, ((B & D) & E) == 0
//
// then that single bit in B must be one and thus the whole expression can be
// folded to
// (A & (B | D)) == (B & (B ^ D)) | E.
//
// For example,
// (icmp ne (A & 12), 0) & (icmp eq (A & 7), 1) -> (icmp eq (A & 15), 9)
// (icmp ne (A & 15), 0) & (icmp eq (A & 7), 0) -> (icmp eq (A & 15), 8)
if ((((*BCst & *DCst) & ECst) == 0) &&
(*BCst & (*BCst ^ *DCst)).isPowerOf2()) {
APInt BorD = *BCst | *DCst;
APInt BandBxorDorE = (*BCst & (*BCst ^ *DCst)) | ECst;
Value *NewMask = ConstantInt::get(A->getType(), BorD);
Value *NewMaskedValue = ConstantInt::get(A->getType(), BandBxorDorE);
Value *NewAnd = Builder.CreateAnd(A, NewMask);
return Builder.CreateICmp(NewCC, NewAnd, NewMaskedValue);
}
auto IsSubSetOrEqual = [](const APInt *C1, const APInt *C2) {
return (*C1 & *C2) == *C1;
};
auto IsSuperSetOrEqual = [](const APInt *C1, const APInt *C2) {
return (*C1 & *C2) == *C2;
};
// In the following, we consider only the cases where B is a superset of D, B
// is a subset of D, or B == D because otherwise there's at least one bit
// covered by B but not D, in which case we can't deduce much from it, so
// no folding (aside from the single must-be-one bit case right above.)
// For example,
// (icmp ne (A & 14), 0) & (icmp eq (A & 3), 1) -> no folding.
if (!IsSubSetOrEqual(BCst, DCst) && !IsSuperSetOrEqual(BCst, DCst))
return nullptr;
// At this point, either B is a superset of D, B is a subset of D or B == D.
// If E is zero, if B is a subset of (or equal to) D, LHS and RHS contradict
// and the whole expression becomes false (or true if negated), otherwise, no
// folding.
// For example,
// (icmp ne (A & 3), 0) & (icmp eq (A & 7), 0) -> false.
// (icmp ne (A & 15), 0) & (icmp eq (A & 3), 0) -> no folding.
if (ECst.isZero()) {
if (IsSubSetOrEqual(BCst, DCst))
return ConstantInt::get(LHS->getType(), !IsAnd);
return nullptr;
}
// At this point, B, D, E aren't zero and (B & D) == B, (B & D) == D or B ==
// D. If B is a superset of (or equal to) D, since E is not zero, LHS is
// subsumed by RHS (RHS implies LHS.) So the whole expression becomes
// RHS. For example,
// (icmp ne (A & 255), 0) & (icmp eq (A & 15), 8) -> (icmp eq (A & 15), 8).
// (icmp ne (A & 15), 0) & (icmp eq (A & 15), 8) -> (icmp eq (A & 15), 8).
if (IsSuperSetOrEqual(BCst, DCst)) {
// We can't guarantee that samesign hold after this fold.
if (auto *ICmp = dyn_cast<ICmpInst>(RHS))
ICmp->setSameSign(false);
return RHS;
}
// Otherwise, B is a subset of D. If B and E have a common bit set,
// ie. (B & E) != 0, then LHS is subsumed by RHS. For example.
// (icmp ne (A & 12), 0) & (icmp eq (A & 15), 8) -> (icmp eq (A & 15), 8).
assert(IsSubSetOrEqual(BCst, DCst) && "Precondition due to above code");
if ((*BCst & ECst) != 0) {
// We can't guarantee that samesign hold after this fold.
if (auto *ICmp = dyn_cast<ICmpInst>(RHS))
ICmp->setSameSign(false);
return RHS;
}
// Otherwise, LHS and RHS contradict and the whole expression becomes false
// (or true if negated.) For example,
// (icmp ne (A & 7), 0) & (icmp eq (A & 15), 8) -> false.
// (icmp ne (A & 6), 0) & (icmp eq (A & 15), 8) -> false.
return ConstantInt::get(LHS->getType(), !IsAnd);
}
/// Try to fold (icmp(A & B) ==/!= 0) &/| (icmp(A & D) ==/!= E) into a single
/// (icmp(A & X) ==/!= Y), where the left-hand side and the right hand side
/// aren't of the common mask pattern type.
/// Also used for logical and/or, must be poison safe.
static Value *foldLogOpOfMaskedICmpsAsymmetric(
Value *LHS, Value *RHS, bool IsAnd, Value *A, Value *B, Value *C, Value *D,
Value *E, ICmpInst::Predicate PredL, ICmpInst::Predicate PredR,
unsigned LHSMask, unsigned RHSMask, InstCombiner::BuilderTy &Builder) {
assert(ICmpInst::isEquality(PredL) && ICmpInst::isEquality(PredR) &&
"Expected equality predicates for masked type of icmps.");
// Handle Mask_NotAllZeros-BMask_Mixed cases.
// (icmp ne/eq (A & B), C) &/| (icmp eq/ne (A & D), E), or
// (icmp eq/ne (A & B), C) &/| (icmp ne/eq (A & D), E)
// which gets swapped to
// (icmp ne/eq (A & D), E) &/| (icmp eq/ne (A & B), C).
if (!IsAnd) {
LHSMask = conjugateICmpMask(LHSMask);
RHSMask = conjugateICmpMask(RHSMask);
}
if ((LHSMask & Mask_NotAllZeros) && (RHSMask & BMask_Mixed)) {
if (Value *V = foldLogOpOfMaskedICmps_NotAllZeros_BMask_Mixed(
LHS, RHS, IsAnd, A, B, D, E, PredL, PredR, Builder)) {
return V;
}
} else if ((LHSMask & BMask_Mixed) && (RHSMask & Mask_NotAllZeros)) {
if (Value *V = foldLogOpOfMaskedICmps_NotAllZeros_BMask_Mixed(
RHS, LHS, IsAnd, A, D, B, C, PredR, PredL, Builder)) {
return V;
}
}
return nullptr;
}
/// Try to fold (icmp(A & B) ==/!= C) &/| (icmp(A & D) ==/!= E)
/// into a single (icmp(A & X) ==/!= Y).
static Value *foldLogOpOfMaskedICmps(Value *LHS, Value *RHS, bool IsAnd,
bool IsLogical,
InstCombiner::BuilderTy &Builder,
const SimplifyQuery &Q) {
Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr, *E = nullptr;
ICmpInst::Predicate PredL, PredR;
std::optional<std::pair<unsigned, unsigned>> MaskPair =
getMaskedTypeForICmpPair(A, B, C, D, E, LHS, RHS, PredL, PredR);
if (!MaskPair)
return nullptr;
assert(ICmpInst::isEquality(PredL) && ICmpInst::isEquality(PredR) &&
"Expected equality predicates for masked type of icmps.");
unsigned LHSMask = MaskPair->first;
unsigned RHSMask = MaskPair->second;
unsigned Mask = LHSMask & RHSMask;
if (Mask == 0) {
// Even if the two sides don't share a common pattern, check if folding can
// still happen.
if (Value *V = foldLogOpOfMaskedICmpsAsymmetric(
LHS, RHS, IsAnd, A, B, C, D, E, PredL, PredR, LHSMask, RHSMask,
Builder))
return V;
return nullptr;
}
// In full generality:
// (icmp (A & B) Op C) | (icmp (A & D) Op E)
// == ![ (icmp (A & B) !Op C) & (icmp (A & D) !Op E) ]
//
// If the latter can be converted into (icmp (A & X) Op Y) then the former is
// equivalent to (icmp (A & X) !Op Y).
//
// Therefore, we can pretend for the rest of this function that we're dealing
// with the conjunction, provided we flip the sense of any comparisons (both
// input and output).
// In most cases we're going to produce an EQ for the "&&" case.
ICmpInst::Predicate NewCC = IsAnd ? ICmpInst::ICMP_EQ : ICmpInst::ICMP_NE;
if (!IsAnd) {
// Convert the masking analysis into its equivalent with negated
// comparisons.
Mask = conjugateICmpMask(Mask);
}
if (Mask & Mask_AllZeros) {
// (icmp eq (A & B), 0) & (icmp eq (A & D), 0)
// -> (icmp eq (A & (B|D)), 0)
if (IsLogical && !isGuaranteedNotToBeUndefOrPoison(D))
return nullptr; // TODO: Use freeze?
Value *NewOr = Builder.CreateOr(B, D);
Value *NewAnd = Builder.CreateAnd(A, NewOr);
// We can't use C as zero because we might actually handle
// (icmp ne (A & B), B) & (icmp ne (A & D), D)
// with B and D, having a single bit set.
Value *Zero = Constant::getNullValue(A->getType());
return Builder.CreateICmp(NewCC, NewAnd, Zero);
}
if (Mask & BMask_AllOnes) {
// (icmp eq (A & B), B) & (icmp eq (A & D), D)
// -> (icmp eq (A & (B|D)), (B|D))
if (IsLogical && !isGuaranteedNotToBeUndefOrPoison(D))
return nullptr; // TODO: Use freeze?
Value *NewOr = Builder.CreateOr(B, D);
Value *NewAnd = Builder.CreateAnd(A, NewOr);
return Builder.CreateICmp(NewCC, NewAnd, NewOr);
}
if (Mask & AMask_AllOnes) {
// (icmp eq (A & B), A) & (icmp eq (A & D), A)
// -> (icmp eq (A & (B&D)), A)
if (IsLogical && !isGuaranteedNotToBeUndefOrPoison(D))
return nullptr; // TODO: Use freeze?
Value *NewAnd1 = Builder.CreateAnd(B, D);
Value *NewAnd2 = Builder.CreateAnd(A, NewAnd1);
return Builder.CreateICmp(NewCC, NewAnd2, A);
}
const APInt *ConstB, *ConstD;
if (match(B, m_APInt(ConstB)) && match(D, m_APInt(ConstD))) {
if (Mask & (Mask_NotAllZeros | BMask_NotAllOnes)) {
// (icmp ne (A & B), 0) & (icmp ne (A & D), 0) and
// (icmp ne (A & B), B) & (icmp ne (A & D), D)
// -> (icmp ne (A & B), 0) or (icmp ne (A & D), 0)
// Only valid if one of the masks is a superset of the other (check "B&D"
// is the same as either B or D).
APInt NewMask = *ConstB & *ConstD;
if (NewMask == *ConstB)
return LHS;
if (NewMask == *ConstD) {
if (IsLogical) {
if (auto *RHSI = dyn_cast<Instruction>(RHS))
RHSI->dropPoisonGeneratingFlags();
}
return RHS;
}
}
if (Mask & AMask_NotAllOnes) {
// (icmp ne (A & B), B) & (icmp ne (A & D), D)
// -> (icmp ne (A & B), A) or (icmp ne (A & D), A)
// Only valid if one of the masks is a superset of the other (check "B|D"
// is the same as either B or D).
APInt NewMask = *ConstB | *ConstD;
if (NewMask == *ConstB)
return LHS;
if (NewMask == *ConstD)
return RHS;
}
if (Mask & (BMask_Mixed | BMask_NotMixed)) {
// Mixed:
// (icmp eq (A & B), C) & (icmp eq (A & D), E)
// We already know that B & C == C && D & E == E.
// If we can prove that (B & D) & (C ^ E) == 0, that is, the bits of
// C and E, which are shared by both the mask B and the mask D, don't
// contradict, then we can transform to
// -> (icmp eq (A & (B|D)), (C|E))
// Currently, we only handle the case of B, C, D, and E being constant.
// We can't simply use C and E because we might actually handle
// (icmp ne (A & B), B) & (icmp eq (A & D), D)
// with B and D, having a single bit set.
// NotMixed:
// (icmp ne (A & B), C) & (icmp ne (A & D), E)
// -> (icmp ne (A & (B & D)), (C & E))
// Check the intersection (B & D) for inequality.
// Assume that (B & D) == B || (B & D) == D, i.e B/D is a subset of D/B
// and (B & D) & (C ^ E) == 0, bits of C and E, which are shared by both
// the B and the D, don't contradict. Note that we can assume (~B & C) ==
// 0 && (~D & E) == 0, previous operation should delete these icmps if it
// hadn't been met.
const APInt *OldConstC, *OldConstE;
if (!match(C, m_APInt(OldConstC)) || !match(E, m_APInt(OldConstE)))
return nullptr;
auto FoldBMixed = [&](ICmpInst::Predicate CC, bool IsNot) -> Value * {
CC = IsNot ? CmpInst::getInversePredicate(CC) : CC;
const APInt ConstC = PredL != CC ? *ConstB ^ *OldConstC : *OldConstC;
const APInt ConstE = PredR != CC ? *ConstD ^ *OldConstE : *OldConstE;
if (((*ConstB & *ConstD) & (ConstC ^ ConstE)).getBoolValue())
return IsNot ? nullptr : ConstantInt::get(LHS->getType(), !IsAnd);
if (IsNot && !ConstB->isSubsetOf(*ConstD) &&
!ConstD->isSubsetOf(*ConstB))
return nullptr;
APInt BD, CE;
if (IsNot) {
BD = *ConstB & *ConstD;
CE = ConstC & ConstE;
} else {
BD = *ConstB | *ConstD;
CE = ConstC | ConstE;
}
Value *NewAnd = Builder.CreateAnd(A, BD);
Value *CEVal = ConstantInt::get(A->getType(), CE);
return Builder.CreateICmp(CC, CEVal, NewAnd);
};
if (Mask & BMask_Mixed)
return FoldBMixed(NewCC, false);
if (Mask & BMask_NotMixed) // can be else also
return FoldBMixed(NewCC, true);
}
}
// (icmp eq (A & B), 0) | (icmp eq (A & D), 0)
// -> (icmp ne (A & (B|D)), (B|D))
// (icmp ne (A & B), 0) & (icmp ne (A & D), 0)
// -> (icmp eq (A & (B|D)), (B|D))
// iff B and D is known to be a power of two
if (Mask & Mask_NotAllZeros &&
isKnownToBeAPowerOfTwo(B, /*OrZero=*/false, /*Depth=*/0, Q) &&
isKnownToBeAPowerOfTwo(D, /*OrZero=*/false, /*Depth=*/0, Q)) {
// If this is a logical and/or, then we must prevent propagation of a
// poison value from the RHS by inserting freeze.
if (IsLogical)
D = Builder.CreateFreeze(D);
Value *Mask = Builder.CreateOr(B, D);
Value *Masked = Builder.CreateAnd(A, Mask);
return Builder.CreateICmp(NewCC, Masked, Mask);
}
return nullptr;
}
/// Try to fold a signed range checked with lower bound 0 to an unsigned icmp.
/// Example: (icmp sge x, 0) & (icmp slt x, n) --> icmp ult x, n
/// If \p Inverted is true then the check is for the inverted range, e.g.
/// (icmp slt x, 0) | (icmp sgt x, n) --> icmp ugt x, n
Value *InstCombinerImpl::simplifyRangeCheck(ICmpInst *Cmp0, ICmpInst *Cmp1,
bool Inverted) {
// Check the lower range comparison, e.g. x >= 0
// InstCombine already ensured that if there is a constant it's on the RHS.
ConstantInt *RangeStart = dyn_cast<ConstantInt>(Cmp0->getOperand(1));
if (!RangeStart)
return nullptr;
ICmpInst::Predicate Pred0 = (Inverted ? Cmp0->getInversePredicate() :
Cmp0->getPredicate());
// Accept x > -1 or x >= 0 (after potentially inverting the predicate).
if (!((Pred0 == ICmpInst::ICMP_SGT && RangeStart->isMinusOne()) ||
(Pred0 == ICmpInst::ICMP_SGE && RangeStart->isZero())))
return nullptr;
ICmpInst::Predicate Pred1 = (Inverted ? Cmp1->getInversePredicate() :
Cmp1->getPredicate());
Value *Input = Cmp0->getOperand(0);
Value *Cmp1Op0 = Cmp1->getOperand(0);
Value *Cmp1Op1 = Cmp1->getOperand(1);
Value *RangeEnd;
if (match(Cmp1Op0, m_SExtOrSelf(m_Specific(Input)))) {
// For the upper range compare we have: icmp x, n
Input = Cmp1Op0;
RangeEnd = Cmp1Op1;
} else if (match(Cmp1Op1, m_SExtOrSelf(m_Specific(Input)))) {
// For the upper range compare we have: icmp n, x
Input = Cmp1Op1;
RangeEnd = Cmp1Op0;
Pred1 = ICmpInst::getSwappedPredicate(Pred1);
} else {
return nullptr;
}
// Check the upper range comparison, e.g. x < n
ICmpInst::Predicate NewPred;
switch (Pred1) {
case ICmpInst::ICMP_SLT: NewPred = ICmpInst::ICMP_ULT; break;
case ICmpInst::ICMP_SLE: NewPred = ICmpInst::ICMP_ULE; break;
default: return nullptr;
}
// This simplification is only valid if the upper range is not negative.
KnownBits Known = computeKnownBits(RangeEnd, /*Depth=*/0, Cmp1);
if (!Known.isNonNegative())
return nullptr;
if (Inverted)
NewPred = ICmpInst::getInversePredicate(NewPred);
return Builder.CreateICmp(NewPred, Input, RangeEnd);
}
// (or (icmp eq X, 0), (icmp eq X, Pow2OrZero))
// -> (icmp eq (and X, Pow2OrZero), X)
// (and (icmp ne X, 0), (icmp ne X, Pow2OrZero))
// -> (icmp ne (and X, Pow2OrZero), X)
static Value *
foldAndOrOfICmpsWithPow2AndWithZero(InstCombiner::BuilderTy &Builder,
ICmpInst *LHS, ICmpInst *RHS, bool IsAnd,
const SimplifyQuery &Q) {
CmpPredicate Pred = IsAnd ? CmpInst::ICMP_NE : CmpInst::ICMP_EQ;
// Make sure we have right compares for our op.
if (LHS->getPredicate() != Pred || RHS->getPredicate() != Pred)
return nullptr;
// Make it so we can match LHS against the (icmp eq/ne X, 0) just for
// simplicity.
if (match(RHS->getOperand(1), m_Zero()))
std::swap(LHS, RHS);
Value *Pow2, *Op;
// Match the desired pattern:
// LHS: (icmp eq/ne X, 0)
// RHS: (icmp eq/ne X, Pow2OrZero)
// Skip if Pow2OrZero is 1. Either way it gets folded to (icmp ugt X, 1) but
// this form ends up slightly less canonical.
// We could potentially be more sophisticated than requiring LHS/RHS
// be one-use. We don't create additional instructions if only one
// of them is one-use. So cases where one is one-use and the other
// is two-use might be profitable.
if (!match(LHS, m_OneUse(m_ICmp(Pred, m_Value(Op), m_Zero()))) ||
!match(RHS, m_OneUse(m_c_ICmp(Pred, m_Specific(Op), m_Value(Pow2)))) ||
match(Pow2, m_One()) ||
!isKnownToBeAPowerOfTwo(Pow2, Q.DL, /*OrZero=*/true, /*Depth=*/0, Q.AC,
Q.CxtI, Q.DT))
return nullptr;
Value *And = Builder.CreateAnd(Op, Pow2);
return Builder.CreateICmp(Pred, And, Op);
}
/// General pattern:
/// X & Y
///
/// Where Y is checking that all the high bits (covered by a mask 4294967168)
/// are uniform, i.e. %arg & 4294967168 can be either 4294967168 or 0
/// Pattern can be one of:
/// %t = add i32 %arg, 128
/// %r = icmp ult i32 %t, 256
/// Or
/// %t0 = shl i32 %arg, 24
/// %t1 = ashr i32 %t0, 24
/// %r = icmp eq i32 %t1, %arg
/// Or
/// %t0 = trunc i32 %arg to i8
/// %t1 = sext i8 %t0 to i32
/// %r = icmp eq i32 %t1, %arg
/// This pattern is a signed truncation check.
///
/// And X is checking that some bit in that same mask is zero.
/// I.e. can be one of:
/// %r = icmp sgt i32 %arg, -1
/// Or
/// %t = and i32 %arg, 2147483648
/// %r = icmp eq i32 %t, 0
///
/// Since we are checking that all the bits in that mask are the same,
/// and a particular bit is zero, what we are really checking is that all the
/// masked bits are zero.
/// So this should be transformed to:
/// %r = icmp ult i32 %arg, 128
static Value *foldSignedTruncationCheck(ICmpInst *ICmp0, ICmpInst *ICmp1,
Instruction &CxtI,
InstCombiner::BuilderTy &Builder) {
assert(CxtI.getOpcode() == Instruction::And);
// Match icmp ult (add %arg, C01), C1 (C1 == C01 << 1; powers of two)
auto tryToMatchSignedTruncationCheck = [](ICmpInst *ICmp, Value *&X,
APInt &SignBitMask) -> bool {
const APInt *I01, *I1; // powers of two; I1 == I01 << 1
if (!(match(ICmp, m_SpecificICmp(ICmpInst::ICMP_ULT,
m_Add(m_Value(X), m_Power2(I01)),
m_Power2(I1))) &&
I1->ugt(*I01) && I01->shl(1) == *I1))
return false;
// Which bit is the new sign bit as per the 'signed truncation' pattern?
SignBitMask = *I01;
return true;
};
// One icmp needs to be 'signed truncation check'.
// We need to match this first, else we will mismatch commutative cases.
Value *X1;
APInt HighestBit;
ICmpInst *OtherICmp;
if (tryToMatchSignedTruncationCheck(ICmp1, X1, HighestBit))
OtherICmp = ICmp0;
else if (tryToMatchSignedTruncationCheck(ICmp0, X1, HighestBit))
OtherICmp = ICmp1;
else
return nullptr;
assert(HighestBit.isPowerOf2() && "expected to be power of two (non-zero)");
// Try to match/decompose into: icmp eq (X & Mask), 0
auto tryToDecompose = [](ICmpInst *ICmp, Value *&X,
APInt &UnsetBitsMask) -> bool {
CmpPredicate Pred = ICmp->getPredicate();
// Can it be decomposed into icmp eq (X & Mask), 0 ?
auto Res =
llvm::decomposeBitTestICmp(ICmp->getOperand(0), ICmp->getOperand(1),
Pred, /*LookThroughTrunc=*/false);
if (Res && Res->Pred == ICmpInst::ICMP_EQ) {
X = Res->X;
UnsetBitsMask = Res->Mask;
return true;
}
// Is it icmp eq (X & Mask), 0 already?
const APInt *Mask;
if (match(ICmp, m_ICmp(Pred, m_And(m_Value(X), m_APInt(Mask)), m_Zero())) &&
Pred == ICmpInst::ICMP_EQ) {
UnsetBitsMask = *Mask;
return true;
}
return false;
};
// And the other icmp needs to be decomposable into a bit test.
Value *X0;
APInt UnsetBitsMask;
if (!tryToDecompose(OtherICmp, X0, UnsetBitsMask))
return nullptr;
assert(!UnsetBitsMask.isZero() && "empty mask makes no sense.");
// Are they working on the same value?
Value *X;
if (X1 == X0) {
// Ok as is.
X = X1;
} else if (match(X0, m_Trunc(m_Specific(X1)))) {
UnsetBitsMask = UnsetBitsMask.zext(X1->getType()->getScalarSizeInBits());
X = X1;
} else
return nullptr;
// So which bits should be uniform as per the 'signed truncation check'?
// (all the bits starting with (i.e. including) HighestBit)
APInt SignBitsMask = ~(HighestBit - 1U);
// UnsetBitsMask must have some common bits with SignBitsMask,
if (!UnsetBitsMask.intersects(SignBitsMask))
return nullptr;
// Does UnsetBitsMask contain any bits outside of SignBitsMask?
if (!UnsetBitsMask.isSubsetOf(SignBitsMask)) {
APInt OtherHighestBit = (~UnsetBitsMask) + 1U;
if (!OtherHighestBit.isPowerOf2())
return nullptr;
HighestBit = APIntOps::umin(HighestBit, OtherHighestBit);
}
// Else, if it does not, then all is ok as-is.
// %r = icmp ult %X, SignBit
return Builder.CreateICmpULT(X, ConstantInt::get(X->getType(), HighestBit),
CxtI.getName() + ".simplified");
}
/// Fold (icmp eq ctpop(X) 1) | (icmp eq X 0) into (icmp ult ctpop(X) 2) and
/// fold (icmp ne ctpop(X) 1) & (icmp ne X 0) into (icmp ugt ctpop(X) 1).
/// Also used for logical and/or, must be poison safe if range attributes are
/// dropped.
static Value *foldIsPowerOf2OrZero(ICmpInst *Cmp0, ICmpInst *Cmp1, bool IsAnd,
InstCombiner::BuilderTy &Builder,
InstCombinerImpl &IC) {
CmpPredicate Pred0, Pred1;
Value *X;
if (!match(Cmp0, m_ICmp(Pred0, m_Intrinsic<Intrinsic::ctpop>(m_Value(X)),
m_SpecificInt(1))) ||
!match(Cmp1, m_ICmp(Pred1, m_Specific(X), m_ZeroInt())))
return nullptr;
auto *CtPop = cast<Instruction>(Cmp0->getOperand(0));
if (IsAnd && Pred0 == ICmpInst::ICMP_NE && Pred1 == ICmpInst::ICMP_NE) {
// Drop range attributes and re-infer them in the next iteration.
CtPop->dropPoisonGeneratingAnnotations();
IC.addToWorklist(CtPop);
return Builder.CreateICmpUGT(CtPop, ConstantInt::get(CtPop->getType(), 1));
}
if (!IsAnd && Pred0 == ICmpInst::ICMP_EQ && Pred1 == ICmpInst::ICMP_EQ) {
// Drop range attributes and re-infer them in the next iteration.
CtPop->dropPoisonGeneratingAnnotations();
IC.addToWorklist(CtPop);
return Builder.CreateICmpULT(CtPop, ConstantInt::get(CtPop->getType(), 2));
}
return nullptr;
}
/// Reduce a pair of compares that check if a value has exactly 1 bit set.
/// Also used for logical and/or, must be poison safe if range attributes are
/// dropped.
static Value *foldIsPowerOf2(ICmpInst *Cmp0, ICmpInst *Cmp1, bool JoinedByAnd,
InstCombiner::BuilderTy &Builder,
InstCombinerImpl &IC) {
// Handle 'and' / 'or' commutation: make the equality check the first operand.
if (JoinedByAnd && Cmp1->getPredicate() == ICmpInst::ICMP_NE)
std::swap(Cmp0, Cmp1);
else if (!JoinedByAnd && Cmp1->getPredicate() == ICmpInst::ICMP_EQ)
std::swap(Cmp0, Cmp1);
// (X != 0) && (ctpop(X) u< 2) --> ctpop(X) == 1
Value *X;
if (JoinedByAnd &&
match(Cmp0, m_SpecificICmp(ICmpInst::ICMP_NE, m_Value(X), m_ZeroInt())) &&
match(Cmp1, m_SpecificICmp(ICmpInst::ICMP_ULT,
m_Intrinsic<Intrinsic::ctpop>(m_Specific(X)),
m_SpecificInt(2)))) {
auto *CtPop = cast<Instruction>(Cmp1->getOperand(0));
// Drop range attributes and re-infer them in the next iteration.
CtPop->dropPoisonGeneratingAnnotations();
IC.addToWorklist(CtPop);
return Builder.CreateICmpEQ(CtPop, ConstantInt::get(CtPop->getType(), 1));
}
// (X == 0) || (ctpop(X) u> 1) --> ctpop(X) != 1
if (!JoinedByAnd &&
match(Cmp0, m_SpecificICmp(ICmpInst::ICMP_EQ, m_Value(X), m_ZeroInt())) &&
match(Cmp1, m_SpecificICmp(ICmpInst::ICMP_UGT,
m_Intrinsic<Intrinsic::ctpop>(m_Specific(X)),
m_SpecificInt(1)))) {
auto *CtPop = cast<Instruction>(Cmp1->getOperand(0));
// Drop range attributes and re-infer them in the next iteration.
CtPop->dropPoisonGeneratingAnnotations();
IC.addToWorklist(CtPop);
return Builder.CreateICmpNE(CtPop, ConstantInt::get(CtPop->getType(), 1));
}
return nullptr;
}
/// Try to fold (icmp(A & B) == 0) & (icmp(A & D) != E) into (icmp A u< D) iff
/// B is a contiguous set of ones starting from the most significant bit
/// (negative power of 2), D and E are equal, and D is a contiguous set of ones
/// starting at the most significant zero bit in B. Parameter B supports masking
/// using undef/poison in either scalar or vector values.
static Value *foldNegativePower2AndShiftedMask(
Value *A, Value *B, Value *D, Value *E, ICmpInst::Predicate PredL,
ICmpInst::Predicate PredR, InstCombiner::BuilderTy &Builder) {
assert(ICmpInst::isEquality(PredL) && ICmpInst::isEquality(PredR) &&
"Expected equality predicates for masked type of icmps.");
if (PredL != ICmpInst::ICMP_EQ || PredR != ICmpInst::ICMP_NE)
return nullptr;
if (!match(B, m_NegatedPower2()) || !match(D, m_ShiftedMask()) ||
!match(E, m_ShiftedMask()))
return nullptr;
// Test scalar arguments for conversion. B has been validated earlier to be a
// negative power of two and thus is guaranteed to have one or more contiguous
// ones starting from the MSB followed by zero or more contiguous zeros. D has
// been validated earlier to be a shifted set of one or more contiguous ones.
// In order to match, B leading ones and D leading zeros should be equal. The
// predicate that B be a negative power of 2 prevents the condition of there
// ever being zero leading ones. Thus 0 == 0 cannot occur. The predicate that
// D always be a shifted mask prevents the condition of D equaling 0. This
// prevents matching the condition where B contains the maximum number of
// leading one bits (-1) and D contains the maximum number of leading zero
// bits (0).
auto isReducible = [](const Value *B, const Value *D, const Value *E) {
const APInt *BCst, *DCst, *ECst;
return match(B, m_APIntAllowPoison(BCst)) && match(D, m_APInt(DCst)) &&
match(E, m_APInt(ECst)) && *DCst == *ECst &&
(isa<PoisonValue>(B) ||
(BCst->countLeadingOnes() == DCst->countLeadingZeros()));
};
// Test vector type arguments for conversion.
if (const auto *BVTy = dyn_cast<VectorType>(B->getType())) {
const auto *BFVTy = dyn_cast<FixedVectorType>(BVTy);
const auto *BConst = dyn_cast<Constant>(B);
const auto *DConst = dyn_cast<Constant>(D);
const auto *EConst = dyn_cast<Constant>(E);
if (!BFVTy || !BConst || !DConst || !EConst)
return nullptr;
for (unsigned I = 0; I != BFVTy->getNumElements(); ++I) {
const auto *BElt = BConst->getAggregateElement(I);
const auto *DElt = DConst->getAggregateElement(I);
const auto *EElt = EConst->getAggregateElement(I);
if (!BElt || !DElt || !EElt)
return nullptr;
if (!isReducible(BElt, DElt, EElt))
return nullptr;
}
} else {
// Test scalar type arguments for conversion.
if (!isReducible(B, D, E))
return nullptr;
}
return Builder.CreateICmp(ICmpInst::ICMP_ULT, A, D);
}
/// Try to fold ((icmp X u< P) & (icmp(X & M) != M)) or ((icmp X s> -1) &
/// (icmp(X & M) != M)) into (icmp X u< M). Where P is a power of 2, M < P, and
/// M is a contiguous shifted mask starting at the right most significant zero
/// bit in P. SGT is supported as when P is the largest representable power of
/// 2, an earlier optimization converts the expression into (icmp X s> -1).
/// Parameter P supports masking using undef/poison in either scalar or vector
/// values.
static Value *foldPowerOf2AndShiftedMask(ICmpInst *Cmp0, ICmpInst *Cmp1,
bool JoinedByAnd,
InstCombiner::BuilderTy &Builder) {
if (!JoinedByAnd)
return nullptr;
Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr, *E = nullptr;
ICmpInst::Predicate CmpPred0, CmpPred1;
// Assuming P is a 2^n, getMaskedTypeForICmpPair will normalize (icmp X u<
// 2^n) into (icmp (X & ~(2^n-1)) == 0) and (icmp X s> -1) into (icmp (X &
// SignMask) == 0).
std::optional<std::pair<unsigned, unsigned>> MaskPair =
getMaskedTypeForICmpPair(A, B, C, D, E, Cmp0, Cmp1, CmpPred0, CmpPred1);
if (!MaskPair)
return nullptr;
const auto compareBMask = BMask_NotMixed | BMask_NotAllOnes;
unsigned CmpMask0 = MaskPair->first;
unsigned CmpMask1 = MaskPair->second;
if ((CmpMask0 & Mask_AllZeros) && (CmpMask1 == compareBMask)) {
if (Value *V = foldNegativePower2AndShiftedMask(A, B, D, E, CmpPred0,
CmpPred1, Builder))
return V;
} else if ((CmpMask0 == compareBMask) && (CmpMask1 & Mask_AllZeros)) {
if (Value *V = foldNegativePower2AndShiftedMask(A, D, B, C, CmpPred1,
CmpPred0, Builder))
return V;
}
return nullptr;
}
/// Commuted variants are assumed to be handled by calling this function again
/// with the parameters swapped.
static Value *foldUnsignedUnderflowCheck(ICmpInst *ZeroICmp,
ICmpInst *UnsignedICmp, bool IsAnd,
const SimplifyQuery &Q,
InstCombiner::BuilderTy &Builder) {
Value *ZeroCmpOp;
CmpPredicate EqPred;
if (!match(ZeroICmp, m_ICmp(EqPred, m_Value(ZeroCmpOp), m_Zero())) ||
!ICmpInst::isEquality(EqPred))
return nullptr;
CmpPredicate UnsignedPred;
Value *A, *B;
if (match(UnsignedICmp,
m_c_ICmp(UnsignedPred, m_Specific(ZeroCmpOp), m_Value(A))) &&
match(ZeroCmpOp, m_c_Add(m_Specific(A), m_Value(B))) &&
(ZeroICmp->hasOneUse() || UnsignedICmp->hasOneUse())) {
auto GetKnownNonZeroAndOther = [&](Value *&NonZero, Value *&Other) {
if (!isKnownNonZero(NonZero, Q))
std::swap(NonZero, Other);
return isKnownNonZero(NonZero, Q);
};
// Given ZeroCmpOp = (A + B)
// ZeroCmpOp < A && ZeroCmpOp != 0 --> (0-X) < Y iff
// ZeroCmpOp >= A || ZeroCmpOp == 0 --> (0-X) >= Y iff
// with X being the value (A/B) that is known to be non-zero,
// and Y being remaining value.
if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_NE &&
IsAnd && GetKnownNonZeroAndOther(B, A))
return Builder.CreateICmpULT(Builder.CreateNeg(B), A);
if (UnsignedPred == ICmpInst::ICMP_UGE && EqPred == ICmpInst::ICMP_EQ &&
!IsAnd && GetKnownNonZeroAndOther(B, A))
return Builder.CreateICmpUGE(Builder.CreateNeg(B), A);
}
return nullptr;
}
struct IntPart {
Value *From;
unsigned StartBit;
unsigned NumBits;
};
/// Match an extraction of bits from an integer.
static std::optional<IntPart> matchIntPart(Value *V) {
Value *X;
if (!match(V, m_OneUse(m_Trunc(m_Value(X)))))
return std::nullopt;
unsigned NumOriginalBits = X->getType()->getScalarSizeInBits();
unsigned NumExtractedBits = V->getType()->getScalarSizeInBits();
Value *Y;
const APInt *Shift;
// For a trunc(lshr Y, Shift) pattern, make sure we're only extracting bits
// from Y, not any shifted-in zeroes.
if (match(X, m_OneUse(m_LShr(m_Value(Y), m_APInt(Shift)))) &&
Shift->ule(NumOriginalBits - NumExtractedBits))
return {{Y, (unsigned)Shift->getZExtValue(), NumExtractedBits}};
return {{X, 0, NumExtractedBits}};
}
/// Materialize an extraction of bits from an integer in IR.
static Value *extractIntPart(const IntPart &P, IRBuilderBase &Builder) {
Value *V = P.From;
if (P.StartBit)
V = Builder.CreateLShr(V, P.StartBit);
Type *TruncTy = V->getType()->getWithNewBitWidth(P.NumBits);
if (TruncTy != V->getType())
V = Builder.CreateTrunc(V, TruncTy);
return V;
}
/// (icmp eq X0, Y0) & (icmp eq X1, Y1) -> icmp eq X01, Y01
/// (icmp ne X0, Y0) | (icmp ne X1, Y1) -> icmp ne X01, Y01
/// where X0, X1 and Y0, Y1 are adjacent parts extracted from an integer.
Value *InstCombinerImpl::foldEqOfParts(Value *Cmp0, Value *Cmp1, bool IsAnd) {
if (!Cmp0->hasOneUse() || !Cmp1->hasOneUse())
return nullptr;
CmpInst::Predicate Pred = IsAnd ? CmpInst::ICMP_EQ : CmpInst::ICMP_NE;
auto GetMatchPart = [&](Value *CmpV,
unsigned OpNo) -> std::optional<IntPart> {
assert(CmpV->getType()->isIntOrIntVectorTy(1) && "Must be bool");
Value *X, *Y;
// icmp ne (and x, 1), (and y, 1) <=> trunc (xor x, y) to i1
// icmp eq (and x, 1), (and y, 1) <=> not (trunc (xor x, y) to i1)
if (Pred == CmpInst::ICMP_NE
? match(CmpV, m_Trunc(m_Xor(m_Value(X), m_Value(Y))))
: match(CmpV, m_Not(m_Trunc(m_Xor(m_Value(X), m_Value(Y))))))
return {{OpNo == 0 ? X : Y, 0, 1}};
auto *Cmp = dyn_cast<ICmpInst>(CmpV);
if (!Cmp)
return std::nullopt;
if (Pred == Cmp->getPredicate())
return matchIntPart(Cmp->getOperand(OpNo));
const APInt *C;
// (icmp eq (lshr x, C), (lshr y, C)) gets optimized to:
// (icmp ult (xor x, y), 1 << C) so also look for that.
if (Pred == CmpInst::ICMP_EQ && Cmp->getPredicate() == CmpInst::ICMP_ULT) {
if (!match(Cmp->getOperand(1), m_Power2(C)) ||
!match(Cmp->getOperand(0), m_Xor(m_Value(), m_Value())))
return std::nullopt;
}
// (icmp ne (lshr x, C), (lshr y, C)) gets optimized to:
// (icmp ugt (xor x, y), (1 << C) - 1) so also look for that.
else if (Pred == CmpInst::ICMP_NE &&
Cmp->getPredicate() == CmpInst::ICMP_UGT) {
if (!match(Cmp->getOperand(1), m_LowBitMask(C)) ||
!match(Cmp->getOperand(0), m_Xor(m_Value(), m_Value())))
return std::nullopt;
} else {
return std::nullopt;
}
unsigned From = Pred == CmpInst::ICMP_NE ? C->popcount() : C->countr_zero();
Instruction *I = cast<Instruction>(Cmp->getOperand(0));
return {{I->getOperand(OpNo), From, C->getBitWidth() - From}};
};
std::optional<IntPart> L0 = GetMatchPart(Cmp0, 0);
std::optional<IntPart> R0 = GetMatchPart(Cmp0, 1);
std::optional<IntPart> L1 = GetMatchPart(Cmp1, 0);
std::optional<IntPart> R1 = GetMatchPart(Cmp1, 1);
if (!L0 || !R0 || !L1 || !R1)
return nullptr;
// Make sure the LHS/RHS compare a part of the same value, possibly after
// an operand swap.
if (L0->From != L1->From || R0->From != R1->From) {
if (L0->From != R1->From || R0->From != L1->From)
return nullptr;
std::swap(L1, R1);
}
// Make sure the extracted parts are adjacent, canonicalizing to L0/R0 being
// the low part and L1/R1 being the high part.
if (L0->StartBit + L0->NumBits != L1->StartBit ||
R0->StartBit + R0->NumBits != R1->StartBit) {
if (L1->StartBit + L1->NumBits != L0->StartBit ||
R1->StartBit + R1->NumBits != R0->StartBit)
return nullptr;
std::swap(L0, L1);
std::swap(R0, R1);
}
// We can simplify to a comparison of these larger parts of the integers.
IntPart L = {L0->From, L0->StartBit, L0->NumBits + L1->NumBits};
IntPart R = {R0->From, R0->StartBit, R0->NumBits + R1->NumBits};
Value *LValue = extractIntPart(L, Builder);
Value *RValue = extractIntPart(R, Builder);
return Builder.CreateICmp(Pred, LValue, RValue);
}
/// Reduce logic-of-compares with equality to a constant by substituting a
/// common operand with the constant. Callers are expected to call this with
/// Cmp0/Cmp1 switched to handle logic op commutativity.
static Value *foldAndOrOfICmpsWithConstEq(ICmpInst *Cmp0, ICmpInst *Cmp1,
bool IsAnd, bool IsLogical,
InstCombiner::BuilderTy &Builder,
const SimplifyQuery &Q) {
// Match an equality compare with a non-poison constant as Cmp0.
// Also, give up if the compare can be constant-folded to avoid looping.
CmpPredicate Pred0;
Value *X;
Constant *C;
if (!match(Cmp0, m_ICmp(Pred0, m_Value(X), m_Constant(C))) ||
!isGuaranteedNotToBeUndefOrPoison(C) || isa<Constant>(X))
return nullptr;
if ((IsAnd && Pred0 != ICmpInst::ICMP_EQ) ||
(!IsAnd && Pred0 != ICmpInst::ICMP_NE))
return nullptr;
// The other compare must include a common operand (X). Canonicalize the
// common operand as operand 1 (Pred1 is swapped if the common operand was
// operand 0).
Value *Y;
CmpPredicate Pred1;
if (!match(Cmp1, m_c_ICmp(Pred1, m_Value(Y), m_Specific(X))))
return nullptr;
// Replace variable with constant value equivalence to remove a variable use:
// (X == C) && (Y Pred1 X) --> (X == C) && (Y Pred1 C)
// (X != C) || (Y Pred1 X) --> (X != C) || (Y Pred1 C)
// Can think of the 'or' substitution with the 'and' bool equivalent:
// A || B --> A || (!A && B)
Value *SubstituteCmp = simplifyICmpInst(Pred1, Y, C, Q);
if (!SubstituteCmp) {
// If we need to create a new instruction, require that the old compare can
// be removed.
if (!Cmp1->hasOneUse())
return nullptr;
SubstituteCmp = Builder.CreateICmp(Pred1, Y, C);
}
if (IsLogical)
return IsAnd ? Builder.CreateLogicalAnd(Cmp0, SubstituteCmp)
: Builder.CreateLogicalOr(Cmp0, SubstituteCmp);
return Builder.CreateBinOp(IsAnd ? Instruction::And : Instruction::Or, Cmp0,
SubstituteCmp);
}
/// Fold (icmp Pred1 V1, C1) & (icmp Pred2 V2, C2)
/// or (icmp Pred1 V1, C1) | (icmp Pred2 V2, C2)
/// into a single comparison using range-based reasoning.
/// NOTE: This is also used for logical and/or, must be poison-safe!
Value *InstCombinerImpl::foldAndOrOfICmpsUsingRanges(ICmpInst *ICmp1,
ICmpInst *ICmp2,
bool IsAnd) {
CmpPredicate Pred1, Pred2;
Value *V1, *V2;
const APInt *C1, *C2;
if (!match(ICmp1, m_ICmp(Pred1, m_Value(V1), m_APInt(C1))) ||
!match(ICmp2, m_ICmp(Pred2, m_Value(V2), m_APInt(C2))))
return nullptr;
// Look through add of a constant offset on V1, V2, or both operands. This
// allows us to interpret the V + C' < C'' range idiom into a proper range.
const APInt *Offset1 = nullptr, *Offset2 = nullptr;
if (V1 != V2) {
Value *X;
if (match(V1, m_Add(m_Value(X), m_APInt(Offset1))))
V1 = X;
if (match(V2, m_Add(m_Value(X), m_APInt(Offset2))))
V2 = X;
}
if (V1 != V2)
return nullptr;
ConstantRange CR1 = ConstantRange::makeExactICmpRegion(
IsAnd ? ICmpInst::getInverseCmpPredicate(Pred1) : Pred1, *C1);
if (Offset1)
CR1 = CR1.subtract(*Offset1);
ConstantRange CR2 = ConstantRange::makeExactICmpRegion(
IsAnd ? ICmpInst::getInverseCmpPredicate(Pred2) : Pred2, *C2);
if (Offset2)
CR2 = CR2.subtract(*Offset2);
Type *Ty = V1->getType();
Value *NewV = V1;
std::optional<ConstantRange> CR = CR1.exactUnionWith(CR2);
if (!CR) {
if (!(ICmp1->hasOneUse() && ICmp2->hasOneUse()) || CR1.isWrappedSet() ||
CR2.isWrappedSet())
return nullptr;
// Check whether we have equal-size ranges that only differ by one bit.
// In that case we can apply a mask to map one range onto the other.
APInt LowerDiff = CR1.getLower() ^ CR2.getLower();
APInt UpperDiff = (CR1.getUpper() - 1) ^ (CR2.getUpper() - 1);
APInt CR1Size = CR1.getUpper() - CR1.getLower();
if (!LowerDiff.isPowerOf2() || LowerDiff != UpperDiff ||
CR1Size != CR2.getUpper() - CR2.getLower())
return nullptr;
CR = CR1.getLower().ult(CR2.getLower()) ? CR1 : CR2;
NewV = Builder.CreateAnd(NewV, ConstantInt::get(Ty, ~LowerDiff));
}
if (IsAnd)
CR = CR->inverse();
CmpInst::Predicate NewPred;
APInt NewC, Offset;
CR->getEquivalentICmp(NewPred, NewC, Offset);
if (Offset != 0)
NewV = Builder.CreateAdd(NewV, ConstantInt::get(Ty, Offset));
return Builder.CreateICmp(NewPred, NewV, ConstantInt::get(Ty, NewC));
}
/// Ignore all operations which only change the sign of a value, returning the
/// underlying magnitude value.
static Value *stripSignOnlyFPOps(Value *Val) {
match(Val, m_FNeg(m_Value(Val)));
match(Val, m_FAbs(m_Value(Val)));
match(Val, m_CopySign(m_Value(Val), m_Value()));
return Val;
}
/// Matches canonical form of isnan, fcmp ord x, 0
static bool matchIsNotNaN(FCmpInst::Predicate P, Value *LHS, Value *RHS) {
return P == FCmpInst::FCMP_ORD && match(RHS, m_AnyZeroFP());
}
/// Matches fcmp u__ x, +/-inf
static bool matchUnorderedInfCompare(FCmpInst::Predicate P, Value *LHS,
Value *RHS) {
return FCmpInst::isUnordered(P) && match(RHS, m_Inf());
}
/// and (fcmp ord x, 0), (fcmp u* x, inf) -> fcmp o* x, inf
///
/// Clang emits this pattern for doing an isfinite check in __builtin_isnormal.
static Value *matchIsFiniteTest(InstCombiner::BuilderTy &Builder, FCmpInst *LHS,
FCmpInst *RHS) {
Value *LHS0 = LHS->getOperand(0), *LHS1 = LHS->getOperand(1);
Value *RHS0 = RHS->getOperand(0), *RHS1 = RHS->getOperand(1);
FCmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
if (!matchIsNotNaN(PredL, LHS0, LHS1) ||
!matchUnorderedInfCompare(PredR, RHS0, RHS1))
return nullptr;
return Builder.CreateFCmpFMF(FCmpInst::getOrderedPredicate(PredR), RHS0, RHS1,
FMFSource::intersect(LHS, RHS));
}
Value *InstCombinerImpl::foldLogicOfFCmps(FCmpInst *LHS, FCmpInst *RHS,
bool IsAnd, bool IsLogicalSelect) {
Value *LHS0 = LHS->getOperand(0), *LHS1 = LHS->getOperand(1);
Value *RHS0 = RHS->getOperand(0), *RHS1 = RHS->getOperand(1);
FCmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
if (LHS0 == RHS1 && RHS0 == LHS1) {
// Swap RHS operands to match LHS.
PredR = FCmpInst::getSwappedPredicate(PredR);
std::swap(RHS0, RHS1);
}
// Simplify (fcmp cc0 x, y) & (fcmp cc1 x, y).
// Suppose the relation between x and y is R, where R is one of
// U(1000), L(0100), G(0010) or E(0001), and CC0 and CC1 are the bitmasks for
// testing the desired relations.
//
// Since (R & CC0) and (R & CC1) are either R or 0, we actually have this:
// bool(R & CC0) && bool(R & CC1)
// = bool((R & CC0) & (R & CC1))
// = bool(R & (CC0 & CC1)) <= by re-association, commutation, and idempotency
//
// Since (R & CC0) and (R & CC1) are either R or 0, we actually have this:
// bool(R & CC0) || bool(R & CC1)
// = bool((R & CC0) | (R & CC1))
// = bool(R & (CC0 | CC1)) <= by reversed distribution (contribution? ;)
if (LHS0 == RHS0 && LHS1 == RHS1) {
unsigned FCmpCodeL = getFCmpCode(PredL);
unsigned FCmpCodeR = getFCmpCode(PredR);
unsigned NewPred = IsAnd ? FCmpCodeL & FCmpCodeR : FCmpCodeL | FCmpCodeR;
// Intersect the fast math flags.
// TODO: We can union the fast math flags unless this is a logical select.
return getFCmpValue(NewPred, LHS0, LHS1, Builder,
FMFSource::intersect(LHS, RHS));
}
// This transform is not valid for a logical select.
if (!IsLogicalSelect &&
((PredL == FCmpInst::FCMP_ORD && PredR == FCmpInst::FCMP_ORD && IsAnd) ||
(PredL == FCmpInst::FCMP_UNO && PredR == FCmpInst::FCMP_UNO &&
!IsAnd))) {
if (LHS0->getType() != RHS0->getType())
return nullptr;
// FCmp canonicalization ensures that (fcmp ord/uno X, X) and
// (fcmp ord/uno X, C) will be transformed to (fcmp X, +0.0).
if (match(LHS1, m_PosZeroFP()) && match(RHS1, m_PosZeroFP())) {
// Ignore the constants because they are obviously not NANs:
// (fcmp ord x, 0.0) & (fcmp ord y, 0.0) -> (fcmp ord x, y)
// (fcmp uno x, 0.0) | (fcmp uno y, 0.0) -> (fcmp uno x, y)
return Builder.CreateFCmpFMF(PredL, LHS0, RHS0,
FMFSource::intersect(LHS, RHS));
}
}
if (IsAnd && stripSignOnlyFPOps(LHS0) == stripSignOnlyFPOps(RHS0)) {
// and (fcmp ord x, 0), (fcmp u* x, inf) -> fcmp o* x, inf
// and (fcmp ord x, 0), (fcmp u* fabs(x), inf) -> fcmp o* x, inf
if (Value *Left = matchIsFiniteTest(Builder, LHS, RHS))
return Left;
if (Value *Right = matchIsFiniteTest(Builder, RHS, LHS))
return Right;
}
// Turn at least two fcmps with constants into llvm.is.fpclass.
//
// If we can represent a combined value test with one class call, we can
// potentially eliminate 4-6 instructions. If we can represent a test with a
// single fcmp with fneg and fabs, that's likely a better canonical form.
if (LHS->hasOneUse() && RHS->hasOneUse()) {
auto [ClassValRHS, ClassMaskRHS] =
fcmpToClassTest(PredR, *RHS->getFunction(), RHS0, RHS1);
if (ClassValRHS) {
auto [ClassValLHS, ClassMaskLHS] =
fcmpToClassTest(PredL, *LHS->getFunction(), LHS0, LHS1);
if (ClassValLHS == ClassValRHS) {
unsigned CombinedMask = IsAnd ? (ClassMaskLHS & ClassMaskRHS)
: (ClassMaskLHS | ClassMaskRHS);
return Builder.CreateIntrinsic(
Intrinsic::is_fpclass, {ClassValLHS->getType()},
{ClassValLHS, Builder.getInt32(CombinedMask)});
}
}
}
// Canonicalize the range check idiom:
// and (fcmp olt/ole/ult/ule x, C), (fcmp ogt/oge/ugt/uge x, -C)
// --> fabs(x) olt/ole/ult/ule C
// or (fcmp ogt/oge/ugt/uge x, C), (fcmp olt/ole/ult/ule x, -C)
// --> fabs(x) ogt/oge/ugt/uge C
// TODO: Generalize to handle a negated variable operand?
const APFloat *LHSC, *RHSC;
if (LHS0 == RHS0 && LHS->hasOneUse() && RHS->hasOneUse() &&
FCmpInst::getSwappedPredicate(PredL) == PredR &&
match(LHS1, m_APFloatAllowPoison(LHSC)) &&
match(RHS1, m_APFloatAllowPoison(RHSC)) &&
LHSC->bitwiseIsEqual(neg(*RHSC))) {
auto IsLessThanOrLessEqual = [](FCmpInst::Predicate Pred) {
switch (Pred) {
case FCmpInst::FCMP_OLT:
case FCmpInst::FCMP_OLE:
case FCmpInst::FCMP_ULT:
case FCmpInst::FCMP_ULE:
return true;
default:
return false;
}
};
if (IsLessThanOrLessEqual(IsAnd ? PredR : PredL)) {
std::swap(LHSC, RHSC);
std::swap(PredL, PredR);
}
if (IsLessThanOrLessEqual(IsAnd ? PredL : PredR)) {
FastMathFlags NewFlag = LHS->getFastMathFlags();
if (!IsLogicalSelect)
NewFlag |= RHS->getFastMathFlags();
Value *FAbs =
Builder.CreateUnaryIntrinsic(Intrinsic::fabs, LHS0, NewFlag);
return Builder.CreateFCmpFMF(
PredL, FAbs, ConstantFP::get(LHS0->getType(), *LHSC), NewFlag);
}
}
return nullptr;
}
/// Match an fcmp against a special value that performs a test possible by
/// llvm.is.fpclass.
static bool matchIsFPClassLikeFCmp(Value *Op, Value *&ClassVal,
uint64_t &ClassMask) {
auto *FCmp = dyn_cast<FCmpInst>(Op);
if (!FCmp || !FCmp->hasOneUse())
return false;
std::tie(ClassVal, ClassMask) =
fcmpToClassTest(FCmp->getPredicate(), *FCmp->getParent()->getParent(),
FCmp->getOperand(0), FCmp->getOperand(1));
return ClassVal != nullptr;
}
/// or (is_fpclass x, mask0), (is_fpclass x, mask1)
/// -> is_fpclass x, (mask0 | mask1)
/// and (is_fpclass x, mask0), (is_fpclass x, mask1)
/// -> is_fpclass x, (mask0 & mask1)
/// xor (is_fpclass x, mask0), (is_fpclass x, mask1)
/// -> is_fpclass x, (mask0 ^ mask1)
Instruction *InstCombinerImpl::foldLogicOfIsFPClass(BinaryOperator &BO,
Value *Op0, Value *Op1) {
Value *ClassVal0 = nullptr;
Value *ClassVal1 = nullptr;
uint64_t ClassMask0, ClassMask1;
// Restrict to folding one fcmp into one is.fpclass for now, don't introduce a
// new class.
//
// TODO: Support forming is.fpclass out of 2 separate fcmps when codegen is
// better.
bool IsLHSClass =
match(Op0, m_OneUse(m_Intrinsic<Intrinsic::is_fpclass>(
m_Value(ClassVal0), m_ConstantInt(ClassMask0))));
bool IsRHSClass =
match(Op1, m_OneUse(m_Intrinsic<Intrinsic::is_fpclass>(
m_Value(ClassVal1), m_ConstantInt(ClassMask1))));
if ((((IsLHSClass || matchIsFPClassLikeFCmp(Op0, ClassVal0, ClassMask0)) &&
(IsRHSClass || matchIsFPClassLikeFCmp(Op1, ClassVal1, ClassMask1)))) &&
ClassVal0 == ClassVal1) {
unsigned NewClassMask;
switch (BO.getOpcode()) {
case Instruction::And:
NewClassMask = ClassMask0 & ClassMask1;
break;
case Instruction::Or:
NewClassMask = ClassMask0 | ClassMask1;
break;
case Instruction::Xor:
NewClassMask = ClassMask0 ^ ClassMask1;
break;
default:
llvm_unreachable("not a binary logic operator");
}
if (IsLHSClass) {
auto *II = cast<IntrinsicInst>(Op0);
II->setArgOperand(
1, ConstantInt::get(II->getArgOperand(1)->getType(), NewClassMask));
return replaceInstUsesWith(BO, II);
}
if (IsRHSClass) {
auto *II = cast<IntrinsicInst>(Op1);
II->setArgOperand(
1, ConstantInt::get(II->getArgOperand(1)->getType(), NewClassMask));
return replaceInstUsesWith(BO, II);
}
CallInst *NewClass =
Builder.CreateIntrinsic(Intrinsic::is_fpclass, {ClassVal0->getType()},
{ClassVal0, Builder.getInt32(NewClassMask)});
return replaceInstUsesWith(BO, NewClass);
}
return nullptr;
}
/// Look for the pattern that conditionally negates a value via math operations:
/// cond.splat = sext i1 cond
/// sub = add cond.splat, x
/// xor = xor sub, cond.splat
/// and rewrite it to do the same, but via logical operations:
/// value.neg = sub 0, value
/// cond = select i1 neg, value.neg, value
Instruction *InstCombinerImpl::canonicalizeConditionalNegationViaMathToSelect(
BinaryOperator &I) {
assert(I.getOpcode() == BinaryOperator::Xor && "Only for xor!");
Value *Cond, *X;
// As per complexity ordering, `xor` is not commutative here.
if (!match(&I, m_c_BinOp(m_OneUse(m_Value()), m_Value())) ||
!match(I.getOperand(1), m_SExt(m_Value(Cond))) ||
!Cond->getType()->isIntOrIntVectorTy(1) ||
!match(I.getOperand(0), m_c_Add(m_SExt(m_Specific(Cond)), m_Value(X))))
return nullptr;
return SelectInst::Create(Cond, Builder.CreateNeg(X, X->getName() + ".neg"),
X);
}
/// This a limited reassociation for a special case (see above) where we are
/// checking if two values are either both NAN (unordered) or not-NAN (ordered).
/// This could be handled more generally in '-reassociation', but it seems like
/// an unlikely pattern for a large number of logic ops and fcmps.
static Instruction *reassociateFCmps(BinaryOperator &BO,
InstCombiner::BuilderTy &Builder) {
Instruction::BinaryOps Opcode = BO.getOpcode();
assert((Opcode == Instruction::And || Opcode == Instruction::Or) &&
"Expecting and/or op for fcmp transform");
// There are 4 commuted variants of the pattern. Canonicalize operands of this
// logic op so an fcmp is operand 0 and a matching logic op is operand 1.
Value *Op0 = BO.getOperand(0), *Op1 = BO.getOperand(1), *X;
if (match(Op1, m_FCmp(m_Value(), m_AnyZeroFP())))
std::swap(Op0, Op1);
// Match inner binop and the predicate for combining 2 NAN checks into 1.
Value *BO10, *BO11;
FCmpInst::Predicate NanPred = Opcode == Instruction::And ? FCmpInst::FCMP_ORD
: FCmpInst::FCMP_UNO;
if (!match(Op0, m_SpecificFCmp(NanPred, m_Value(X), m_AnyZeroFP())) ||
!match(Op1, m_BinOp(Opcode, m_Value(BO10), m_Value(BO11))))
return nullptr;
// The inner logic op must have a matching fcmp operand.
Value *Y;
if (!match(BO10, m_SpecificFCmp(NanPred, m_Value(Y), m_AnyZeroFP())) ||
X->getType() != Y->getType())
std::swap(BO10, BO11);
if (!match(BO10, m_SpecificFCmp(NanPred, m_Value(Y), m_AnyZeroFP())) ||
X->getType() != Y->getType())
return nullptr;
// and (fcmp ord X, 0), (and (fcmp ord Y, 0), Z) --> and (fcmp ord X, Y), Z
// or (fcmp uno X, 0), (or (fcmp uno Y, 0), Z) --> or (fcmp uno X, Y), Z
// Intersect FMF from the 2 source fcmps.
Value *NewFCmp =
Builder.CreateFCmpFMF(NanPred, X, Y, FMFSource::intersect(Op0, BO10));
return BinaryOperator::Create(Opcode, NewFCmp, BO11);
}
/// Match variations of De Morgan's Laws:
/// (~A & ~B) == (~(A | B))
/// (~A | ~B) == (~(A & B))
static Instruction *matchDeMorgansLaws(BinaryOperator &I,
InstCombiner &IC) {
const Instruction::BinaryOps Opcode = I.getOpcode();
assert((Opcode == Instruction::And || Opcode == Instruction::Or) &&
"Trying to match De Morgan's Laws with something other than and/or");
// Flip the logic operation.
const Instruction::BinaryOps FlippedOpcode =
(Opcode == Instruction::And) ? Instruction::Or : Instruction::And;
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
Value *A, *B;
if (match(Op0, m_OneUse(m_Not(m_Value(A)))) &&
match(Op1, m_OneUse(m_Not(m_Value(B)))) &&
!IC.isFreeToInvert(A, A->hasOneUse()) &&
!IC.isFreeToInvert(B, B->hasOneUse())) {
Value *AndOr =
IC.Builder.CreateBinOp(FlippedOpcode, A, B, I.getName() + ".demorgan");
return BinaryOperator::CreateNot(AndOr);
}
// The 'not' ops may require reassociation.
// (A & ~B) & ~C --> A & ~(B | C)
// (~B & A) & ~C --> A & ~(B | C)
// (A | ~B) | ~C --> A | ~(B & C)
// (~B | A) | ~C --> A | ~(B & C)
Value *C;
if (match(Op0, m_OneUse(m_c_BinOp(Opcode, m_Value(A), m_Not(m_Value(B))))) &&
match(Op1, m_Not(m_Value(C)))) {
Value *FlippedBO = IC.Builder.CreateBinOp(FlippedOpcode, B, C);
return BinaryOperator::Create(Opcode, A, IC.Builder.CreateNot(FlippedBO));
}
return nullptr;
}
bool InstCombinerImpl::shouldOptimizeCast(CastInst *CI) {
Value *CastSrc = CI->getOperand(0);
// Noop casts and casts of constants should be eliminated trivially.
if (CI->getSrcTy() == CI->getDestTy() || isa<Constant>(CastSrc))
return false;
// If this cast is paired with another cast that can be eliminated, we prefer
// to have it eliminated.
if (const auto *PrecedingCI = dyn_cast<CastInst>(CastSrc))
if (isEliminableCastPair(PrecedingCI, CI))
return false;
return true;
}
/// Fold {and,or,xor} (cast X), C.
static Instruction *foldLogicCastConstant(BinaryOperator &Logic, CastInst *Cast,
InstCombinerImpl &IC) {
Constant *C = dyn_cast<Constant>(Logic.getOperand(1));
if (!C)
return nullptr;
auto LogicOpc = Logic.getOpcode();
Type *DestTy = Logic.getType();
Type *SrcTy = Cast->getSrcTy();
// Move the logic operation ahead of a zext or sext if the constant is
// unchanged in the smaller source type. Performing the logic in a smaller
// type may provide more information to later folds, and the smaller logic
// instruction may be cheaper (particularly in the case of vectors).
Value *X;
if (match(Cast, m_OneUse(m_ZExt(m_Value(X))))) {
if (Constant *TruncC = IC.getLosslessUnsignedTrunc(C, SrcTy)) {
// LogicOpc (zext X), C --> zext (LogicOpc X, C)
Value *NewOp = IC.Builder.CreateBinOp(LogicOpc, X, TruncC);
return new ZExtInst(NewOp, DestTy);
}
}
if (match(Cast, m_OneUse(m_SExtLike(m_Value(X))))) {
if (Constant *TruncC = IC.getLosslessSignedTrunc(C, SrcTy)) {
// LogicOpc (sext X), C --> sext (LogicOpc X, C)
Value *NewOp = IC.Builder.CreateBinOp(LogicOpc, X, TruncC);
return new SExtInst(NewOp, DestTy);
}
}
return nullptr;
}
/// Fold {and,or,xor} (cast X), Y.
Instruction *InstCombinerImpl::foldCastedBitwiseLogic(BinaryOperator &I) {
auto LogicOpc = I.getOpcode();
assert(I.isBitwiseLogicOp() && "Unexpected opcode for bitwise logic folding");
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
// fold bitwise(A >> BW - 1, zext(icmp)) (BW is the scalar bits of the
// type of A)
// -> bitwise(zext(A < 0), zext(icmp))
// -> zext(bitwise(A < 0, icmp))
auto FoldBitwiseICmpZeroWithICmp = [&](Value *Op0,
Value *Op1) -> Instruction * {
Value *A;
bool IsMatched =
match(Op0,
m_OneUse(m_LShr(
m_Value(A),
m_SpecificInt(Op0->getType()->getScalarSizeInBits() - 1)))) &&
match(Op1, m_OneUse(m_ZExt(m_ICmp(m_Value(), m_Value()))));
if (!IsMatched)
return nullptr;
auto *ICmpL =
Builder.CreateICmpSLT(A, Constant::getNullValue(A->getType()));
auto *ICmpR = cast<ZExtInst>(Op1)->getOperand(0);
auto *BitwiseOp = Builder.CreateBinOp(LogicOpc, ICmpL, ICmpR);
return new ZExtInst(BitwiseOp, Op0->getType());
};
if (auto *Ret = FoldBitwiseICmpZeroWithICmp(Op0, Op1))
return Ret;
if (auto *Ret = FoldBitwiseICmpZeroWithICmp(Op1, Op0))
return Ret;
CastInst *Cast0 = dyn_cast<CastInst>(Op0);
if (!Cast0)
return nullptr;
// This must be a cast from an integer or integer vector source type to allow
// transformation of the logic operation to the source type.
Type *DestTy = I.getType();
Type *SrcTy = Cast0->getSrcTy();
if (!SrcTy->isIntOrIntVectorTy())
return nullptr;
if (Instruction *Ret = foldLogicCastConstant(I, Cast0, *this))
return Ret;
CastInst *Cast1 = dyn_cast<CastInst>(Op1);
if (!Cast1)
return nullptr;
// Both operands of the logic operation are casts. The casts must be the
// same kind for reduction.
Instruction::CastOps CastOpcode = Cast0->getOpcode();
if (CastOpcode != Cast1->getOpcode())
return nullptr;
// If the source types do not match, but the casts are matching extends, we
// can still narrow the logic op.
if (SrcTy != Cast1->getSrcTy()) {
Value *X, *Y;
if (match(Cast0, m_OneUse(m_ZExtOrSExt(m_Value(X)))) &&
match(Cast1, m_OneUse(m_ZExtOrSExt(m_Value(Y))))) {
// Cast the narrower source to the wider source type.
unsigned XNumBits = X->getType()->getScalarSizeInBits();
unsigned YNumBits = Y->getType()->getScalarSizeInBits();
if (XNumBits < YNumBits)
X = Builder.CreateCast(CastOpcode, X, Y->getType());
else
Y = Builder.CreateCast(CastOpcode, Y, X->getType());
// Do the logic op in the intermediate width, then widen more.
Value *NarrowLogic = Builder.CreateBinOp(LogicOpc, X, Y);
return CastInst::Create(CastOpcode, NarrowLogic, DestTy);
}
// Give up for other cast opcodes.
return nullptr;
}
Value *Cast0Src = Cast0->getOperand(0);
Value *Cast1Src = Cast1->getOperand(0);
// fold logic(cast(A), cast(B)) -> cast(logic(A, B))
if ((Cast0->hasOneUse() || Cast1->hasOneUse()) &&
shouldOptimizeCast(Cast0) && shouldOptimizeCast(Cast1)) {
Value *NewOp = Builder.CreateBinOp(LogicOpc, Cast0Src, Cast1Src,
I.getName());
return CastInst::Create(CastOpcode, NewOp, DestTy);
}
return nullptr;
}
static Instruction *foldAndToXor(BinaryOperator &I,
InstCombiner::BuilderTy &Builder) {
assert(I.getOpcode() == Instruction::And);
Value *Op0 = I.getOperand(0);
Value *Op1 = I.getOperand(1);
Value *A, *B;
// Operand complexity canonicalization guarantees that the 'or' is Op0.
// (A | B) & ~(A & B) --> A ^ B
// (A | B) & ~(B & A) --> A ^ B
if (match(&I, m_BinOp(m_Or(m_Value(A), m_Value(B)),
m_Not(m_c_And(m_Deferred(A), m_Deferred(B))))))
return BinaryOperator::CreateXor(A, B);
// (A | ~B) & (~A | B) --> ~(A ^ B)
// (A | ~B) & (B | ~A) --> ~(A ^ B)
// (~B | A) & (~A | B) --> ~(A ^ B)
// (~B | A) & (B | ~A) --> ~(A ^ B)
if (Op0->hasOneUse() || Op1->hasOneUse())
if (match(&I, m_BinOp(m_c_Or(m_Value(A), m_Not(m_Value(B))),
m_c_Or(m_Not(m_Deferred(A)), m_Deferred(B)))))
return BinaryOperator::CreateNot(Builder.CreateXor(A, B));
return nullptr;
}
static Instruction *foldOrToXor(BinaryOperator &I,
InstCombiner::BuilderTy &Builder) {
assert(I.getOpcode() == Instruction::Or);
Value *Op0 = I.getOperand(0);
Value *Op1 = I.getOperand(1);
Value *A, *B;
// Operand complexity canonicalization guarantees that the 'and' is Op0.
// (A & B) | ~(A | B) --> ~(A ^ B)
// (A & B) | ~(B | A) --> ~(A ^ B)
if (Op0->hasOneUse() || Op1->hasOneUse())
if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
match(Op1, m_Not(m_c_Or(m_Specific(A), m_Specific(B)))))
return BinaryOperator::CreateNot(Builder.CreateXor(A, B));
// Operand complexity canonicalization guarantees that the 'xor' is Op0.
// (A ^ B) | ~(A | B) --> ~(A & B)
// (A ^ B) | ~(B | A) --> ~(A & B)
if (Op0->hasOneUse() || Op1->hasOneUse())
if (match(Op0, m_Xor(m_Value(A), m_Value(B))) &&
match(Op1, m_Not(m_c_Or(m_Specific(A), m_Specific(B)))))
return BinaryOperator::CreateNot(Builder.CreateAnd(A, B));
// (A & ~B) | (~A & B) --> A ^ B
// (A & ~B) | (B & ~A) --> A ^ B
// (~B & A) | (~A & B) --> A ^ B
// (~B & A) | (B & ~A) --> A ^ B
if (match(Op0, m_c_And(m_Value(A), m_Not(m_Value(B)))) &&
match(Op1, m_c_And(m_Not(m_Specific(A)), m_Specific(B))))
return BinaryOperator::CreateXor(A, B);
return nullptr;
}
/// Return true if a constant shift amount is always less than the specified
/// bit-width. If not, the shift could create poison in the narrower type.
static bool canNarrowShiftAmt(Constant *C, unsigned BitWidth) {
APInt Threshold(C->getType()->getScalarSizeInBits(), BitWidth);
return match(C, m_SpecificInt_ICMP(ICmpInst::ICMP_ULT, Threshold));
}
/// Try to use narrower ops (sink zext ops) for an 'and' with binop operand and
/// a common zext operand: and (binop (zext X), C), (zext X).
Instruction *InstCombinerImpl::narrowMaskedBinOp(BinaryOperator &And) {
// This transform could also apply to {or, and, xor}, but there are better
// folds for those cases, so we don't expect those patterns here. AShr is not
// handled because it should always be transformed to LShr in this sequence.
// The subtract transform is different because it has a constant on the left.
// Add/mul commute the constant to RHS; sub with constant RHS becomes add.
Value *Op0 = And.getOperand(0), *Op1 = And.getOperand(1);
Constant *C;
if (!match(Op0, m_OneUse(m_Add(m_Specific(Op1), m_Constant(C)))) &&
!match(Op0, m_OneUse(m_Mul(m_Specific(Op1), m_Constant(C)))) &&
!match(Op0, m_OneUse(m_LShr(m_Specific(Op1), m_Constant(C)))) &&
!match(Op0, m_OneUse(m_Shl(m_Specific(Op1), m_Constant(C)))) &&
!match(Op0, m_OneUse(m_Sub(m_Constant(C), m_Specific(Op1)))))
return nullptr;
Value *X;
if (!match(Op1, m_ZExt(m_Value(X))) || Op1->hasNUsesOrMore(3))
return nullptr;
Type *Ty = And.getType();
if (!isa<VectorType>(Ty) && !shouldChangeType(Ty, X->getType()))
return nullptr;
// If we're narrowing a shift, the shift amount must be safe (less than the
// width) in the narrower type. If the shift amount is greater, instsimplify
// usually handles that case, but we can't guarantee/assert it.
Instruction::BinaryOps Opc = cast<BinaryOperator>(Op0)->getOpcode();
if (Opc == Instruction::LShr || Opc == Instruction::Shl)
if (!canNarrowShiftAmt(C, X->getType()->getScalarSizeInBits()))
return nullptr;
// and (sub C, (zext X)), (zext X) --> zext (and (sub C', X), X)
// and (binop (zext X), C), (zext X) --> zext (and (binop X, C'), X)
Value *NewC = ConstantExpr::getTrunc(C, X->getType());
Value *NewBO = Opc == Instruction::Sub ? Builder.CreateBinOp(Opc, NewC, X)
: Builder.CreateBinOp(Opc, X, NewC);
return new ZExtInst(Builder.CreateAnd(NewBO, X), Ty);
}
/// Try folding relatively complex patterns for both And and Or operations
/// with all And and Or swapped.
static Instruction *foldComplexAndOrPatterns(BinaryOperator &I,
InstCombiner::BuilderTy &Builder) {
const Instruction::BinaryOps Opcode = I.getOpcode();
assert(Opcode == Instruction::And || Opcode == Instruction::Or);
// Flip the logic operation.
const Instruction::BinaryOps FlippedOpcode =
(Opcode == Instruction::And) ? Instruction::Or : Instruction::And;
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
Value *A, *B, *C, *X, *Y, *Dummy;
// Match following expressions:
// (~(A | B) & C)
// (~(A & B) | C)
// Captures X = ~(A | B) or ~(A & B)
const auto matchNotOrAnd =
[Opcode, FlippedOpcode](Value *Op, auto m_A, auto m_B, auto m_C,
Value *&X, bool CountUses = false) -> bool {
if (CountUses && !Op->hasOneUse())
return false;
if (match(Op, m_c_BinOp(FlippedOpcode,
m_CombineAnd(m_Value(X),
m_Not(m_c_BinOp(Opcode, m_A, m_B))),
m_C)))
return !CountUses || X->hasOneUse();
return false;
};
// (~(A | B) & C) | ... --> ...
// (~(A & B) | C) & ... --> ...
// TODO: One use checks are conservative. We just need to check that a total
// number of multiple used values does not exceed reduction
// in operations.
if (matchNotOrAnd(Op0, m_Value(A), m_Value(B), m_Value(C), X)) {
// (~(A | B) & C) | (~(A | C) & B) --> (B ^ C) & ~A
// (~(A & B) | C) & (~(A & C) | B) --> ~((B ^ C) & A)
if (matchNotOrAnd(Op1, m_Specific(A), m_Specific(C), m_Specific(B), Dummy,
true)) {
Value *Xor = Builder.CreateXor(B, C);
return (Opcode == Instruction::Or)
? BinaryOperator::CreateAnd(Xor, Builder.CreateNot(A))
: BinaryOperator::CreateNot(Builder.CreateAnd(Xor, A));
}
// (~(A | B) & C) | (~(B | C) & A) --> (A ^ C) & ~B
// (~(A & B) | C) & (~(B & C) | A) --> ~((A ^ C) & B)
if (matchNotOrAnd(Op1, m_Specific(B), m_Specific(C), m_Specific(A), Dummy,
true)) {
Value *Xor = Builder.CreateXor(A, C);
return (Opcode == Instruction::Or)
? BinaryOperator::CreateAnd(Xor, Builder.CreateNot(B))
: BinaryOperator::CreateNot(Builder.CreateAnd(Xor, B));
}
// (~(A | B) & C) | ~(A | C) --> ~((B & C) | A)
// (~(A & B) | C) & ~(A & C) --> ~((B | C) & A)
if (match(Op1, m_OneUse(m_Not(m_OneUse(
m_c_BinOp(Opcode, m_Specific(A), m_Specific(C)))))))
return BinaryOperator::CreateNot(Builder.CreateBinOp(
Opcode, Builder.CreateBinOp(FlippedOpcode, B, C), A));
// (~(A | B) & C) | ~(B | C) --> ~((A & C) | B)
// (~(A & B) | C) & ~(B & C) --> ~((A | C) & B)
if (match(Op1, m_OneUse(m_Not(m_OneUse(
m_c_BinOp(Opcode, m_Specific(B), m_Specific(C)))))))
return BinaryOperator::CreateNot(Builder.CreateBinOp(
Opcode, Builder.CreateBinOp(FlippedOpcode, A, C), B));
// (~(A | B) & C) | ~(C | (A ^ B)) --> ~((A | B) & (C | (A ^ B)))
// Note, the pattern with swapped and/or is not handled because the
// result is more undefined than a source:
// (~(A & B) | C) & ~(C & (A ^ B)) --> (A ^ B ^ C) | ~(A | C) is invalid.
if (Opcode == Instruction::Or && Op0->hasOneUse() &&
match(Op1, m_OneUse(m_Not(m_CombineAnd(
m_Value(Y),
m_c_BinOp(Opcode, m_Specific(C),
m_c_Xor(m_Specific(A), m_Specific(B)))))))) {
// X = ~(A | B)
// Y = (C | (A ^ B)
Value *Or = cast<BinaryOperator>(X)->getOperand(0);
return BinaryOperator::CreateNot(Builder.CreateAnd(Or, Y));
}
}
// (~A & B & C) | ... --> ...
// (~A | B | C) | ... --> ...
// TODO: One use checks are conservative. We just need to check that a total
// number of multiple used values does not exceed reduction
// in operations.
if (match(Op0,
m_OneUse(m_c_BinOp(FlippedOpcode,
m_BinOp(FlippedOpcode, m_Value(B), m_Value(C)),
m_CombineAnd(m_Value(X), m_Not(m_Value(A)))))) ||
match(Op0, m_OneUse(m_c_BinOp(
FlippedOpcode,
m_c_BinOp(FlippedOpcode, m_Value(C),
m_CombineAnd(m_Value(X), m_Not(m_Value(A)))),
m_Value(B))))) {
// X = ~A
// (~A & B & C) | ~(A | B | C) --> ~(A | (B ^ C))
// (~A | B | C) & ~(A & B & C) --> (~A | (B ^ C))
if (match(Op1, m_OneUse(m_Not(m_c_BinOp(
Opcode, m_c_BinOp(Opcode, m_Specific(A), m_Specific(B)),
m_Specific(C))))) ||
match(Op1, m_OneUse(m_Not(m_c_BinOp(
Opcode, m_c_BinOp(Opcode, m_Specific(B), m_Specific(C)),
m_Specific(A))))) ||
match(Op1, m_OneUse(m_Not(m_c_BinOp(
Opcode, m_c_BinOp(Opcode, m_Specific(A), m_Specific(C)),
m_Specific(B)))))) {
Value *Xor = Builder.CreateXor(B, C);
return (Opcode == Instruction::Or)
? BinaryOperator::CreateNot(Builder.CreateOr(Xor, A))
: BinaryOperator::CreateOr(Xor, X);
}
// (~A & B & C) | ~(A | B) --> (C | ~B) & ~A
// (~A | B | C) & ~(A & B) --> (C & ~B) | ~A
if (match(Op1, m_OneUse(m_Not(m_OneUse(
m_c_BinOp(Opcode, m_Specific(A), m_Specific(B)))))))
return BinaryOperator::Create(
FlippedOpcode, Builder.CreateBinOp(Opcode, C, Builder.CreateNot(B)),
X);
// (~A & B & C) | ~(A | C) --> (B | ~C) & ~A
// (~A | B | C) & ~(A & C) --> (B & ~C) | ~A
if (match(Op1, m_OneUse(m_Not(m_OneUse(
m_c_BinOp(Opcode, m_Specific(A), m_Specific(C)))))))
return BinaryOperator::Create(
FlippedOpcode, Builder.CreateBinOp(Opcode, B, Builder.CreateNot(C)),
X);
}
return nullptr;
}
/// Try to reassociate a pair of binops so that values with one use only are
/// part of the same instruction. This may enable folds that are limited with
/// multi-use restrictions and makes it more likely to match other patterns that
/// are looking for a common operand.
static Instruction *reassociateForUses(BinaryOperator &BO,
InstCombinerImpl::BuilderTy &Builder) {
Instruction::BinaryOps Opcode = BO.getOpcode();
Value *X, *Y, *Z;
if (match(&BO,
m_c_BinOp(Opcode, m_OneUse(m_BinOp(Opcode, m_Value(X), m_Value(Y))),
m_OneUse(m_Value(Z))))) {
if (!isa<Constant>(X) && !isa<Constant>(Y) && !isa<Constant>(Z)) {
// (X op Y) op Z --> (Y op Z) op X
if (!X->hasOneUse()) {
Value *YZ = Builder.CreateBinOp(Opcode, Y, Z);
return BinaryOperator::Create(Opcode, YZ, X);
}
// (X op Y) op Z --> (X op Z) op Y
if (!Y->hasOneUse()) {
Value *XZ = Builder.CreateBinOp(Opcode, X, Z);
return BinaryOperator::Create(Opcode, XZ, Y);
}
}
}
return nullptr;
}
// Match
// (X + C2) | C
// (X + C2) ^ C
// (X + C2) & C
// and convert to do the bitwise logic first:
// (X | C) + C2
// (X ^ C) + C2
// (X & C) + C2
// iff bits affected by logic op are lower than last bit affected by math op
static Instruction *canonicalizeLogicFirst(BinaryOperator &I,
InstCombiner::BuilderTy &Builder) {
Type *Ty = I.getType();
Instruction::BinaryOps OpC = I.getOpcode();
Value *Op0 = I.getOperand(0);
Value *Op1 = I.getOperand(1);
Value *X;
const APInt *C, *C2;
if (!(match(Op0, m_OneUse(m_Add(m_Value(X), m_APInt(C2)))) &&
match(Op1, m_APInt(C))))
return nullptr;
unsigned Width = Ty->getScalarSizeInBits();
unsigned LastOneMath = Width - C2->countr_zero();
switch (OpC) {
case Instruction::And:
if (C->countl_one() < LastOneMath)
return nullptr;
break;
case Instruction::Xor:
case Instruction::Or:
if (C->countl_zero() < LastOneMath)
return nullptr;
break;
default:
llvm_unreachable("Unexpected BinaryOp!");
}
Value *NewBinOp = Builder.CreateBinOp(OpC, X, ConstantInt::get(Ty, *C));
return BinaryOperator::CreateWithCopiedFlags(Instruction::Add, NewBinOp,
ConstantInt::get(Ty, *C2), Op0);
}
// binop(shift(ShiftedC1, ShAmt), shift(ShiftedC2, add(ShAmt, AddC))) ->
// shift(binop(ShiftedC1, shift(ShiftedC2, AddC)), ShAmt)
// where both shifts are the same and AddC is a valid shift amount.
Instruction *InstCombinerImpl::foldBinOpOfDisplacedShifts(BinaryOperator &I) {
assert((I.isBitwiseLogicOp() || I.getOpcode() == Instruction::Add) &&
"Unexpected opcode");
Value *ShAmt;
Constant *ShiftedC1, *ShiftedC2, *AddC;
Type *Ty = I.getType();
unsigned BitWidth = Ty->getScalarSizeInBits();
if (!match(&I, m_c_BinOp(m_Shift(m_ImmConstant(ShiftedC1), m_Value(ShAmt)),
m_Shift(m_ImmConstant(ShiftedC2),
m_AddLike(m_Deferred(ShAmt),
m_ImmConstant(AddC))))))
return nullptr;
// Make sure the add constant is a valid shift amount.
if (!match(AddC,
m_SpecificInt_ICMP(ICmpInst::ICMP_ULT, APInt(BitWidth, BitWidth))))
return nullptr;
// Avoid constant expressions.
auto *Op0Inst = dyn_cast<Instruction>(I.getOperand(0));
auto *Op1Inst = dyn_cast<Instruction>(I.getOperand(1));
if (!Op0Inst || !Op1Inst)
return nullptr;
// Both shifts must be the same.
Instruction::BinaryOps ShiftOp =
static_cast<Instruction::BinaryOps>(Op0Inst->getOpcode());
if (ShiftOp != Op1Inst->getOpcode())
return nullptr;
// For adds, only left shifts are supported.
if (I.getOpcode() == Instruction::Add && ShiftOp != Instruction::Shl)
return nullptr;
Value *NewC = Builder.CreateBinOp(
I.getOpcode(), ShiftedC1, Builder.CreateBinOp(ShiftOp, ShiftedC2, AddC));
return BinaryOperator::Create(ShiftOp, NewC, ShAmt);
}
// Fold and/or/xor with two equal intrinsic IDs:
// bitwise(fshl (A, B, ShAmt), fshl(C, D, ShAmt))
// -> fshl(bitwise(A, C), bitwise(B, D), ShAmt)
// bitwise(fshr (A, B, ShAmt), fshr(C, D, ShAmt))
// -> fshr(bitwise(A, C), bitwise(B, D), ShAmt)
// bitwise(bswap(A), bswap(B)) -> bswap(bitwise(A, B))
// bitwise(bswap(A), C) -> bswap(bitwise(A, bswap(C)))
// bitwise(bitreverse(A), bitreverse(B)) -> bitreverse(bitwise(A, B))
// bitwise(bitreverse(A), C) -> bitreverse(bitwise(A, bitreverse(C)))
static Instruction *
foldBitwiseLogicWithIntrinsics(BinaryOperator &I,
InstCombiner::BuilderTy &Builder) {
assert(I.isBitwiseLogicOp() && "Should and/or/xor");
if (!I.getOperand(0)->hasOneUse())
return nullptr;
IntrinsicInst *X = dyn_cast<IntrinsicInst>(I.getOperand(0));
if (!X)
return nullptr;
IntrinsicInst *Y = dyn_cast<IntrinsicInst>(I.getOperand(1));
if (Y && (!Y->hasOneUse() || X->getIntrinsicID() != Y->getIntrinsicID()))
return nullptr;
Intrinsic::ID IID = X->getIntrinsicID();
const APInt *RHSC;
// Try to match constant RHS.
if (!Y && (!(IID == Intrinsic::bswap || IID == Intrinsic::bitreverse) ||
!match(I.getOperand(1), m_APInt(RHSC))))
return nullptr;
switch (IID) {
case Intrinsic::fshl:
case Intrinsic::fshr: {
if (X->getOperand(2) != Y->getOperand(2))
return nullptr;
Value *NewOp0 =
Builder.CreateBinOp(I.getOpcode(), X->getOperand(0), Y->getOperand(0));
Value *NewOp1 =
Builder.CreateBinOp(I.getOpcode(), X->getOperand(1), Y->getOperand(1));
Function *F =
Intrinsic::getOrInsertDeclaration(I.getModule(), IID, I.getType());
return CallInst::Create(F, {NewOp0, NewOp1, X->getOperand(2)});
}
case Intrinsic::bswap:
case Intrinsic::bitreverse: {
Value *NewOp0 = Builder.CreateBinOp(
I.getOpcode(), X->getOperand(0),
Y ? Y->getOperand(0)
: ConstantInt::get(I.getType(), IID == Intrinsic::bswap
? RHSC->byteSwap()
: RHSC->reverseBits()));
Function *F =
Intrinsic::getOrInsertDeclaration(I.getModule(), IID, I.getType());
return CallInst::Create(F, {NewOp0});
}
default:
return nullptr;
}
}
// Try to simplify V by replacing occurrences of Op with RepOp, but only look
// through bitwise operations. In particular, for X | Y we try to replace Y with
// 0 inside X and for X & Y we try to replace Y with -1 inside X.
// Return the simplified result of X if successful, and nullptr otherwise.
// If SimplifyOnly is true, no new instructions will be created.
static Value *simplifyAndOrWithOpReplaced(Value *V, Value *Op, Value *RepOp,
bool SimplifyOnly,
InstCombinerImpl &IC,
unsigned Depth = 0) {
if (Op == RepOp)
return nullptr;
if (V == Op)
return RepOp;
auto *I = dyn_cast<BinaryOperator>(V);
if (!I || !I->isBitwiseLogicOp() || Depth >= 3)
return nullptr;
if (!I->hasOneUse())
SimplifyOnly = true;
Value *NewOp0 = simplifyAndOrWithOpReplaced(I->getOperand(0), Op, RepOp,
SimplifyOnly, IC, Depth + 1);
Value *NewOp1 = simplifyAndOrWithOpReplaced(I->getOperand(1), Op, RepOp,
SimplifyOnly, IC, Depth + 1);
if (!NewOp0 && !NewOp1)
return nullptr;
if (!NewOp0)
NewOp0 = I->getOperand(0);
if (!NewOp1)
NewOp1 = I->getOperand(1);
if (Value *Res = simplifyBinOp(I->getOpcode(), NewOp0, NewOp1,
IC.getSimplifyQuery().getWithInstruction(I)))
return Res;
if (SimplifyOnly)
return nullptr;
return IC.Builder.CreateBinOp(I->getOpcode(), NewOp0, NewOp1);
}
/// Reassociate and/or expressions to see if we can fold the inner and/or ops.
/// TODO: Make this recursive; it's a little tricky because an arbitrary
/// number of and/or instructions might have to be created.
Value *InstCombinerImpl::reassociateBooleanAndOr(Value *LHS, Value *X, Value *Y,
Instruction &I, bool IsAnd,
bool RHSIsLogical) {
Instruction::BinaryOps Opcode = IsAnd ? Instruction::And : Instruction::Or;
// LHS bop (X lop Y) --> (LHS bop X) lop Y
// LHS bop (X bop Y) --> (LHS bop X) bop Y
if (Value *Res = foldBooleanAndOr(LHS, X, I, IsAnd, /*IsLogical=*/false))
return RHSIsLogical ? Builder.CreateLogicalOp(Opcode, Res, Y)
: Builder.CreateBinOp(Opcode, Res, Y);
// LHS bop (X bop Y) --> X bop (LHS bop Y)
// LHS bop (X lop Y) --> X lop (LHS bop Y)
if (Value *Res = foldBooleanAndOr(LHS, Y, I, IsAnd, /*IsLogical=*/false))
return RHSIsLogical ? Builder.CreateLogicalOp(Opcode, X, Res)
: Builder.CreateBinOp(Opcode, X, Res);
return nullptr;
}
// FIXME: We use commutative matchers (m_c_*) for some, but not all, matches
// here. We should standardize that construct where it is needed or choose some
// other way to ensure that commutated variants of patterns are not missed.
Instruction *InstCombinerImpl::visitAnd(BinaryOperator &I) {
Type *Ty = I.getType();
if (Value *V = simplifyAndInst(I.getOperand(0), I.getOperand(1),
SQ.getWithInstruction(&I)))
return replaceInstUsesWith(I, V);
if (SimplifyAssociativeOrCommutative(I))
return &I;
if (Instruction *X = foldVectorBinop(I))
return X;
if (Instruction *Phi = foldBinopWithPhiOperands(I))
return Phi;
// See if we can simplify any instructions used by the instruction whose sole
// purpose is to compute bits we don't care about.
if (SimplifyDemandedInstructionBits(I))
return &I;
// Do this before using distributive laws to catch simple and/or/not patterns.
if (Instruction *Xor = foldAndToXor(I, Builder))
return Xor;
if (Instruction *X = foldComplexAndOrPatterns(I, Builder))
return X;
// (A|B)&(A|C) -> A|(B&C) etc
if (Value *V = foldUsingDistributiveLaws(I))
return replaceInstUsesWith(I, V);
if (Instruction *R = foldBinOpShiftWithShift(I))
return R;
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
Value *X, *Y;
const APInt *C;
if ((match(Op0, m_OneUse(m_LogicalShift(m_One(), m_Value(X)))) ||
(match(Op0, m_OneUse(m_Shl(m_APInt(C), m_Value(X)))) && (*C)[0])) &&
match(Op1, m_One())) {
// (1 >> X) & 1 --> zext(X == 0)
// (C << X) & 1 --> zext(X == 0), when C is odd
Value *IsZero = Builder.CreateICmpEQ(X, ConstantInt::get(Ty, 0));
return new ZExtInst(IsZero, Ty);
}
// (-(X & 1)) & Y --> (X & 1) == 0 ? 0 : Y
Value *Neg;
if (match(&I,
m_c_And(m_CombineAnd(m_Value(Neg),
m_OneUse(m_Neg(m_And(m_Value(), m_One())))),
m_Value(Y)))) {
Value *Cmp = Builder.CreateIsNull(Neg);
return SelectInst::Create(Cmp, ConstantInt::getNullValue(Ty), Y);
}
// Canonicalize:
// (X +/- Y) & Y --> ~X & Y when Y is a power of 2.
if (match(&I, m_c_And(m_Value(Y), m_OneUse(m_CombineOr(
m_c_Add(m_Value(X), m_Deferred(Y)),
m_Sub(m_Value(X), m_Deferred(Y)))))) &&
isKnownToBeAPowerOfTwo(Y, /*OrZero*/ true, /*Depth*/ 0, &I))
return BinaryOperator::CreateAnd(Builder.CreateNot(X), Y);
if (match(Op1, m_APInt(C))) {
const APInt *XorC;
if (match(Op0, m_OneUse(m_Xor(m_Value(X), m_APInt(XorC))))) {
// (X ^ C1) & C2 --> (X & C2) ^ (C1&C2)
Constant *NewC = ConstantInt::get(Ty, *C & *XorC);
Value *And = Builder.CreateAnd(X, Op1);
And->takeName(Op0);
return BinaryOperator::CreateXor(And, NewC);
}
const APInt *OrC;
if (match(Op0, m_OneUse(m_Or(m_Value(X), m_APInt(OrC))))) {
// (X | C1) & C2 --> (X & C2^(C1&C2)) | (C1&C2)
// NOTE: This reduces the number of bits set in the & mask, which
// can expose opportunities for store narrowing for scalars.
// NOTE: SimplifyDemandedBits should have already removed bits from C1
// that aren't set in C2. Meaning we can replace (C1&C2) with C1 in
// above, but this feels safer.
APInt Together = *C & *OrC;
Value *And = Builder.CreateAnd(X, ConstantInt::get(Ty, Together ^ *C));
And->takeName(Op0);
return BinaryOperator::CreateOr(And, ConstantInt::get(Ty, Together));
}
unsigned Width = Ty->getScalarSizeInBits();
const APInt *ShiftC;
if (match(Op0, m_OneUse(m_SExt(m_AShr(m_Value(X), m_APInt(ShiftC))))) &&
ShiftC->ult(Width)) {
if (*C == APInt::getLowBitsSet(Width, Width - ShiftC->getZExtValue())) {
// We are clearing high bits that were potentially set by sext+ashr:
// and (sext (ashr X, ShiftC)), C --> lshr (sext X), ShiftC
Value *Sext = Builder.CreateSExt(X, Ty);
Constant *ShAmtC = ConstantInt::get(Ty, ShiftC->zext(Width));
return BinaryOperator::CreateLShr(Sext, ShAmtC);
}
}
// If this 'and' clears the sign-bits added by ashr, replace with lshr:
// and (ashr X, ShiftC), C --> lshr X, ShiftC
if (match(Op0, m_AShr(m_Value(X), m_APInt(ShiftC))) && ShiftC->ult(Width) &&
C->isMask(Width - ShiftC->getZExtValue()))
return BinaryOperator::CreateLShr(X, ConstantInt::get(Ty, *ShiftC));
const APInt *AddC;
if (match(Op0, m_Add(m_Value(X), m_APInt(AddC)))) {
// If we are masking the result of the add down to exactly one bit and
// the constant we are adding has no bits set below that bit, then the
// add is flipping a single bit. Example:
// (X + 4) & 4 --> (X & 4) ^ 4
if (Op0->hasOneUse() && C->isPowerOf2() && (*AddC & (*C - 1)) == 0) {
assert((*C & *AddC) != 0 && "Expected common bit");
Value *NewAnd = Builder.CreateAnd(X, Op1);
return BinaryOperator::CreateXor(NewAnd, Op1);
}
}
// ((C1 OP zext(X)) & C2) -> zext((C1 OP X) & C2) if C2 fits in the
// bitwidth of X and OP behaves well when given trunc(C1) and X.
auto isNarrowableBinOpcode = [](BinaryOperator *B) {
switch (B->getOpcode()) {
case Instruction::Xor:
case Instruction::Or:
case Instruction::Mul:
case Instruction::Add:
case Instruction::Sub:
return true;
default:
return false;
}
};
BinaryOperator *BO;
if (match(Op0, m_OneUse(m_BinOp(BO))) && isNarrowableBinOpcode(BO)) {
Instruction::BinaryOps BOpcode = BO->getOpcode();
Value *X;
const APInt *C1;
// TODO: The one-use restrictions could be relaxed a little if the AND
// is going to be removed.
// Try to narrow the 'and' and a binop with constant operand:
// and (bo (zext X), C1), C --> zext (and (bo X, TruncC1), TruncC)
if (match(BO, m_c_BinOp(m_OneUse(m_ZExt(m_Value(X))), m_APInt(C1))) &&
C->isIntN(X->getType()->getScalarSizeInBits())) {
unsigned XWidth = X->getType()->getScalarSizeInBits();
Constant *TruncC1 = ConstantInt::get(X->getType(), C1->trunc(XWidth));
Value *BinOp = isa<ZExtInst>(BO->getOperand(0))
? Builder.CreateBinOp(BOpcode, X, TruncC1)
: Builder.CreateBinOp(BOpcode, TruncC1, X);
Constant *TruncC = ConstantInt::get(X->getType(), C->trunc(XWidth));
Value *And = Builder.CreateAnd(BinOp, TruncC);
return new ZExtInst(And, Ty);
}
// Similar to above: if the mask matches the zext input width, then the
// 'and' can be eliminated, so we can truncate the other variable op:
// and (bo (zext X), Y), C --> zext (bo X, (trunc Y))
if (isa<Instruction>(BO->getOperand(0)) &&
match(BO->getOperand(0), m_OneUse(m_ZExt(m_Value(X)))) &&
C->isMask(X->getType()->getScalarSizeInBits())) {
Y = BO->getOperand(1);
Value *TrY = Builder.CreateTrunc(Y, X->getType(), Y->getName() + ".tr");
Value *NewBO =
Builder.CreateBinOp(BOpcode, X, TrY, BO->getName() + ".narrow");
return new ZExtInst(NewBO, Ty);
}
// and (bo Y, (zext X)), C --> zext (bo (trunc Y), X)
if (isa<Instruction>(BO->getOperand(1)) &&
match(BO->getOperand(1), m_OneUse(m_ZExt(m_Value(X)))) &&
C->isMask(X->getType()->getScalarSizeInBits())) {
Y = BO->getOperand(0);
Value *TrY = Builder.CreateTrunc(Y, X->getType(), Y->getName() + ".tr");
Value *NewBO =
Builder.CreateBinOp(BOpcode, TrY, X, BO->getName() + ".narrow");
return new ZExtInst(NewBO, Ty);
}
}
// This is intentionally placed after the narrowing transforms for
// efficiency (transform directly to the narrow logic op if possible).
// If the mask is only needed on one incoming arm, push the 'and' op up.
if (match(Op0, m_OneUse(m_Xor(m_Value(X), m_Value(Y)))) ||
match(Op0, m_OneUse(m_Or(m_Value(X), m_Value(Y))))) {
APInt NotAndMask(~(*C));
BinaryOperator::BinaryOps BinOp = cast<BinaryOperator>(Op0)->getOpcode();
if (MaskedValueIsZero(X, NotAndMask, 0, &I)) {
// Not masking anything out for the LHS, move mask to RHS.
// and ({x}or X, Y), C --> {x}or X, (and Y, C)
Value *NewRHS = Builder.CreateAnd(Y, Op1, Y->getName() + ".masked");
return BinaryOperator::Create(BinOp, X, NewRHS);
}
if (!isa<Constant>(Y) && MaskedValueIsZero(Y, NotAndMask, 0, &I)) {
// Not masking anything out for the RHS, move mask to LHS.
// and ({x}or X, Y), C --> {x}or (and X, C), Y
Value *NewLHS = Builder.CreateAnd(X, Op1, X->getName() + ".masked");
return BinaryOperator::Create(BinOp, NewLHS, Y);
}
}
// When the mask is a power-of-2 constant and op0 is a shifted-power-of-2
// constant, test if the shift amount equals the offset bit index:
// (ShiftC << X) & C --> X == (log2(C) - log2(ShiftC)) ? C : 0
// (ShiftC >> X) & C --> X == (log2(ShiftC) - log2(C)) ? C : 0
if (C->isPowerOf2() &&
match(Op0, m_OneUse(m_LogicalShift(m_Power2(ShiftC), m_Value(X))))) {
int Log2ShiftC = ShiftC->exactLogBase2();
int Log2C = C->exactLogBase2();
bool IsShiftLeft =
cast<BinaryOperator>(Op0)->getOpcode() == Instruction::Shl;
int BitNum = IsShiftLeft ? Log2C - Log2ShiftC : Log2ShiftC - Log2C;
assert(BitNum >= 0 && "Expected demanded bits to handle impossible mask");
Value *Cmp = Builder.CreateICmpEQ(X, ConstantInt::get(Ty, BitNum));
return SelectInst::Create(Cmp, ConstantInt::get(Ty, *C),
ConstantInt::getNullValue(Ty));
}
Constant *C1, *C2;
const APInt *C3 = C;
Value *X;
if (C3->isPowerOf2()) {
Constant *Log2C3 = ConstantInt::get(Ty, C3->countr_zero());
if (match(Op0, m_OneUse(m_LShr(m_Shl(m_ImmConstant(C1), m_Value(X)),
m_ImmConstant(C2)))) &&
match(C1, m_Power2())) {
Constant *Log2C1 = ConstantExpr::getExactLogBase2(C1);
Constant *LshrC = ConstantExpr::getAdd(C2, Log2C3);
KnownBits KnownLShrc = computeKnownBits(LshrC, 0, nullptr);
if (KnownLShrc.getMaxValue().ult(Width)) {
// iff C1,C3 is pow2 and C2 + cttz(C3) < BitWidth:
// ((C1 << X) >> C2) & C3 -> X == (cttz(C3)+C2-cttz(C1)) ? C3 : 0
Constant *CmpC = ConstantExpr::getSub(LshrC, Log2C1);
Value *Cmp = Builder.CreateICmpEQ(X, CmpC);
return SelectInst::Create(Cmp, ConstantInt::get(Ty, *C3),
ConstantInt::getNullValue(Ty));
}
}
if (match(Op0, m_OneUse(m_Shl(m_LShr(m_ImmConstant(C1), m_Value(X)),
m_ImmConstant(C2)))) &&
match(C1, m_Power2())) {
Constant *Log2C1 = ConstantExpr::getExactLogBase2(C1);
Constant *Cmp =
ConstantFoldCompareInstOperands(ICmpInst::ICMP_ULT, Log2C3, C2, DL);
if (Cmp && Cmp->isZeroValue()) {
// iff C1,C3 is pow2 and Log2(C3) >= C2:
// ((C1 >> X) << C2) & C3 -> X == (cttz(C1)+C2-cttz(C3)) ? C3 : 0
Constant *ShlC = ConstantExpr::getAdd(C2, Log2C1);
Constant *CmpC = ConstantExpr::getSub(ShlC, Log2C3);
Value *Cmp = Builder.CreateICmpEQ(X, CmpC);
return SelectInst::Create(Cmp, ConstantInt::get(Ty, *C3),
ConstantInt::getNullValue(Ty));
}
}
}
}
// If we are clearing the sign bit of a floating-point value, convert this to
// fabs, then cast back to integer.
//
// This is a generous interpretation for noimplicitfloat, this is not a true
// floating-point operation.
//
// Assumes any IEEE-represented type has the sign bit in the high bit.
// TODO: Unify with APInt matcher. This version allows undef unlike m_APInt
Value *CastOp;
if (match(Op0, m_ElementWiseBitCast(m_Value(CastOp))) &&
match(Op1, m_MaxSignedValue()) &&
!Builder.GetInsertBlock()->getParent()->hasFnAttribute(
Attribute::NoImplicitFloat)) {
Type *EltTy = CastOp->getType()->getScalarType();
if (EltTy->isFloatingPointTy() && EltTy->isIEEE()) {
Value *FAbs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, CastOp);
return new BitCastInst(FAbs, I.getType());
}
}
// and(shl(zext(X), Y), SignMask) -> and(sext(X), SignMask)
// where Y is a valid shift amount.
if (match(&I, m_And(m_OneUse(m_Shl(m_ZExt(m_Value(X)), m_Value(Y))),
m_SignMask())) &&
match(Y, m_SpecificInt_ICMP(
ICmpInst::Predicate::ICMP_EQ,
APInt(Ty->getScalarSizeInBits(),
Ty->getScalarSizeInBits() -
X->getType()->getScalarSizeInBits())))) {
auto *SExt = Builder.CreateSExt(X, Ty, X->getName() + ".signext");
return BinaryOperator::CreateAnd(SExt, Op1);
}
if (Instruction *Z = narrowMaskedBinOp(I))
return Z;
if (I.getType()->isIntOrIntVectorTy(1)) {
if (auto *SI0 = dyn_cast<SelectInst>(Op0)) {
if (auto *R =
foldAndOrOfSelectUsingImpliedCond(Op1, *SI0, /* IsAnd */ true))
return R;
}
if (auto *SI1 = dyn_cast<SelectInst>(Op1)) {
if (auto *R =
foldAndOrOfSelectUsingImpliedCond(Op0, *SI1, /* IsAnd */ true))
return R;
}
}
if (Instruction *FoldedLogic = foldBinOpIntoSelectOrPhi(I))
return FoldedLogic;
if (Instruction *DeMorgan = matchDeMorgansLaws(I, *this))
return DeMorgan;
{
Value *A, *B, *C;
// A & ~(A ^ B) --> A & B
if (match(Op1, m_Not(m_c_Xor(m_Specific(Op0), m_Value(B)))))
return BinaryOperator::CreateAnd(Op0, B);
// ~(A ^ B) & A --> A & B
if (match(Op0, m_Not(m_c_Xor(m_Specific(Op1), m_Value(B)))))
return BinaryOperator::CreateAnd(Op1, B);
// (A ^ B) & ((B ^ C) ^ A) -> (A ^ B) & ~C
if (match(Op0, m_Xor(m_Value(A), m_Value(B))) &&
match(Op1, m_Xor(m_Xor(m_Specific(B), m_Value(C)), m_Specific(A)))) {
Value *NotC = Op1->hasOneUse()
? Builder.CreateNot(C)
: getFreelyInverted(C, C->hasOneUse(), &Builder);
if (NotC != nullptr)
return BinaryOperator::CreateAnd(Op0, NotC);
}
// ((A ^ C) ^ B) & (B ^ A) -> (B ^ A) & ~C
if (match(Op0, m_Xor(m_Xor(m_Value(A), m_Value(C)), m_Value(B))) &&
match(Op1, m_Xor(m_Specific(B), m_Specific(A)))) {
Value *NotC = Op0->hasOneUse()
? Builder.CreateNot(C)
: getFreelyInverted(C, C->hasOneUse(), &Builder);
if (NotC != nullptr)
return BinaryOperator::CreateAnd(Op1, Builder.CreateNot(C));
}
// (A | B) & (~A ^ B) -> A & B
// (A | B) & (B ^ ~A) -> A & B
// (B | A) & (~A ^ B) -> A & B
// (B | A) & (B ^ ~A) -> A & B
if (match(Op1, m_c_Xor(m_Not(m_Value(A)), m_Value(B))) &&
match(Op0, m_c_Or(m_Specific(A), m_Specific(B))))
return BinaryOperator::CreateAnd(A, B);
// (~A ^ B) & (A | B) -> A & B
// (~A ^ B) & (B | A) -> A & B
// (B ^ ~A) & (A | B) -> A & B
// (B ^ ~A) & (B | A) -> A & B
if (match(Op0, m_c_Xor(m_Not(m_Value(A)), m_Value(B))) &&
match(Op1, m_c_Or(m_Specific(A), m_Specific(B))))
return BinaryOperator::CreateAnd(A, B);
// (~A | B) & (A ^ B) -> ~A & B
// (~A | B) & (B ^ A) -> ~A & B
// (B | ~A) & (A ^ B) -> ~A & B
// (B | ~A) & (B ^ A) -> ~A & B
if (match(Op0, m_c_Or(m_Not(m_Value(A)), m_Value(B))) &&
match(Op1, m_c_Xor(m_Specific(A), m_Specific(B))))
return BinaryOperator::CreateAnd(Builder.CreateNot(A), B);
// (A ^ B) & (~A | B) -> ~A & B
// (B ^ A) & (~A | B) -> ~A & B
// (A ^ B) & (B | ~A) -> ~A & B
// (B ^ A) & (B | ~A) -> ~A & B
if (match(Op1, m_c_Or(m_Not(m_Value(A)), m_Value(B))) &&
match(Op0, m_c_Xor(m_Specific(A), m_Specific(B))))
return BinaryOperator::CreateAnd(Builder.CreateNot(A), B);
}
if (Value *Res =
foldBooleanAndOr(Op0, Op1, I, /*IsAnd=*/true, /*IsLogical=*/false))
return replaceInstUsesWith(I, Res);
if (match(Op1, m_OneUse(m_LogicalAnd(m_Value(X), m_Value(Y))))) {
bool IsLogical = isa<SelectInst>(Op1);
if (auto *V = reassociateBooleanAndOr(Op0, X, Y, I, /*IsAnd=*/true,
/*RHSIsLogical=*/IsLogical))
return replaceInstUsesWith(I, V);
}
if (match(Op0, m_OneUse(m_LogicalAnd(m_Value(X), m_Value(Y))))) {
bool IsLogical = isa<SelectInst>(Op0);
if (auto *V = reassociateBooleanAndOr(Op1, X, Y, I, /*IsAnd=*/true,
/*RHSIsLogical=*/IsLogical))
return replaceInstUsesWith(I, V);
}
if (Instruction *FoldedFCmps = reassociateFCmps(I, Builder))
return FoldedFCmps;
if (Instruction *CastedAnd = foldCastedBitwiseLogic(I))
return CastedAnd;
if (Instruction *Sel = foldBinopOfSextBoolToSelect(I))
return Sel;
// and(sext(A), B) / and(B, sext(A)) --> A ? B : 0, where A is i1 or <N x i1>.
// TODO: Move this into foldBinopOfSextBoolToSelect as a more generalized fold
// with binop identity constant. But creating a select with non-constant
// arm may not be reversible due to poison semantics. Is that a good
// canonicalization?
Value *A, *B;
if (match(&I, m_c_And(m_SExt(m_Value(A)), m_Value(B))) &&
A->getType()->isIntOrIntVectorTy(1))
return SelectInst::Create(A, B, Constant::getNullValue(Ty));
// Similarly, a 'not' of the bool translates to a swap of the select arms:
// ~sext(A) & B / B & ~sext(A) --> A ? 0 : B
if (match(&I, m_c_And(m_Not(m_SExt(m_Value(A))), m_Value(B))) &&
A->getType()->isIntOrIntVectorTy(1))
return SelectInst::Create(A, Constant::getNullValue(Ty), B);
// and(zext(A), B) -> A ? (B & 1) : 0
if (match(&I, m_c_And(m_OneUse(m_ZExt(m_Value(A))), m_Value(B))) &&
A->getType()->isIntOrIntVectorTy(1))
return SelectInst::Create(A, Builder.CreateAnd(B, ConstantInt::get(Ty, 1)),
Constant::getNullValue(Ty));
// (-1 + A) & B --> A ? 0 : B where A is 0/1.
if (match(&I, m_c_And(m_OneUse(m_Add(m_ZExtOrSelf(m_Value(A)), m_AllOnes())),
m_Value(B)))) {
if (A->getType()->isIntOrIntVectorTy(1))
return SelectInst::Create(A, Constant::getNullValue(Ty), B);
if (computeKnownBits(A, /* Depth */ 0, &I).countMaxActiveBits() <= 1) {
return SelectInst::Create(
Builder.CreateICmpEQ(A, Constant::getNullValue(A->getType())), B,
Constant::getNullValue(Ty));
}
}
// (iN X s>> (N-1)) & Y --> (X s< 0) ? Y : 0 -- with optional sext
if (match(&I, m_c_And(m_OneUse(m_SExtOrSelf(
m_AShr(m_Value(X), m_APIntAllowPoison(C)))),
m_Value(Y))) &&
*C == X->getType()->getScalarSizeInBits() - 1) {
Value *IsNeg = Builder.CreateIsNeg(X, "isneg");
return SelectInst::Create(IsNeg, Y, ConstantInt::getNullValue(Ty));
}
// If there's a 'not' of the shifted value, swap the select operands:
// ~(iN X s>> (N-1)) & Y --> (X s< 0) ? 0 : Y -- with optional sext
if (match(&I, m_c_And(m_OneUse(m_SExtOrSelf(
m_Not(m_AShr(m_Value(X), m_APIntAllowPoison(C))))),
m_Value(Y))) &&
*C == X->getType()->getScalarSizeInBits() - 1) {
Value *IsNeg = Builder.CreateIsNeg(X, "isneg");
return SelectInst::Create(IsNeg, ConstantInt::getNullValue(Ty), Y);
}
// (~x) & y --> ~(x | (~y)) iff that gets rid of inversions
if (sinkNotIntoOtherHandOfLogicalOp(I))
return &I;
// An and recurrence w/loop invariant step is equivelent to (and start, step)
PHINode *PN = nullptr;
Value *Start = nullptr, *Step = nullptr;
if (matchSimpleRecurrence(&I, PN, Start, Step) && DT.dominates(Step, PN))
return replaceInstUsesWith(I, Builder.CreateAnd(Start, Step));
if (Instruction *R = reassociateForUses(I, Builder))
return R;
if (Instruction *Canonicalized = canonicalizeLogicFirst(I, Builder))
return Canonicalized;
if (Instruction *Folded = foldLogicOfIsFPClass(I, Op0, Op1))
return Folded;
if (Instruction *Res = foldBinOpOfDisplacedShifts(I))
return Res;
if (Instruction *Res = foldBitwiseLogicWithIntrinsics(I, Builder))
return Res;
if (Value *V =
simplifyAndOrWithOpReplaced(Op0, Op1, Constant::getAllOnesValue(Ty),
/*SimplifyOnly*/ false, *this))
return BinaryOperator::CreateAnd(V, Op1);
if (Value *V =
simplifyAndOrWithOpReplaced(Op1, Op0, Constant::getAllOnesValue(Ty),
/*SimplifyOnly*/ false, *this))
return BinaryOperator::CreateAnd(Op0, V);
return nullptr;
}
Instruction *InstCombinerImpl::matchBSwapOrBitReverse(Instruction &I,
bool MatchBSwaps,
bool MatchBitReversals) {
SmallVector<Instruction *, 4> Insts;
if (!recognizeBSwapOrBitReverseIdiom(&I, MatchBSwaps, MatchBitReversals,
Insts))
return nullptr;
Instruction *LastInst = Insts.pop_back_val();
LastInst->removeFromParent();
for (auto *Inst : Insts) {
Inst->setDebugLoc(I.getDebugLoc());
Worklist.push(Inst);
}
return LastInst;
}
std::optional<std::pair<Intrinsic::ID, SmallVector<Value *, 3>>>
InstCombinerImpl::convertOrOfShiftsToFunnelShift(Instruction &Or) {
// TODO: Can we reduce the code duplication between this and the related
// rotate matching code under visitSelect and visitTrunc?
assert(Or.getOpcode() == BinaryOperator::Or && "Expecting or instruction");
unsigned Width = Or.getType()->getScalarSizeInBits();
Instruction *Or0, *Or1;
if (!match(Or.getOperand(0), m_Instruction(Or0)) ||
!match(Or.getOperand(1), m_Instruction(Or1)))
return std::nullopt;
bool IsFshl = true; // Sub on LSHR.
SmallVector<Value *, 3> FShiftArgs;
// First, find an or'd pair of opposite shifts:
// or (lshr ShVal0, ShAmt0), (shl ShVal1, ShAmt1)
if (isa<BinaryOperator>(Or0) && isa<BinaryOperator>(Or1)) {
Value *ShVal0, *ShVal1, *ShAmt0, *ShAmt1;
if (!match(Or0,
m_OneUse(m_LogicalShift(m_Value(ShVal0), m_Value(ShAmt0)))) ||
!match(Or1,
m_OneUse(m_LogicalShift(m_Value(ShVal1), m_Value(ShAmt1)))) ||
Or0->getOpcode() == Or1->getOpcode())
return std::nullopt;
// Canonicalize to or(shl(ShVal0, ShAmt0), lshr(ShVal1, ShAmt1)).
if (Or0->getOpcode() == BinaryOperator::LShr) {
std::swap(Or0, Or1);
std::swap(ShVal0, ShVal1);
std::swap(ShAmt0, ShAmt1);
}
assert(Or0->getOpcode() == BinaryOperator::Shl &&
Or1->getOpcode() == BinaryOperator::LShr &&
"Illegal or(shift,shift) pair");
// Match the shift amount operands for a funnel shift pattern. This always
// matches a subtraction on the R operand.
auto matchShiftAmount = [&](Value *L, Value *R, unsigned Width) -> Value * {
// Check for constant shift amounts that sum to the bitwidth.
const APInt *LI, *RI;
if (match(L, m_APIntAllowPoison(LI)) && match(R, m_APIntAllowPoison(RI)))
if (LI->ult(Width) && RI->ult(Width) && (*LI + *RI) == Width)
return ConstantInt::get(L->getType(), *LI);
Constant *LC, *RC;
if (match(L, m_Constant(LC)) && match(R, m_Constant(RC)) &&
match(L,
m_SpecificInt_ICMP(ICmpInst::ICMP_ULT, APInt(Width, Width))) &&
match(R,
m_SpecificInt_ICMP(ICmpInst::ICMP_ULT, APInt(Width, Width))) &&
match(ConstantExpr::getAdd(LC, RC), m_SpecificIntAllowPoison(Width)))
return ConstantExpr::mergeUndefsWith(LC, RC);
// (shl ShVal, X) | (lshr ShVal, (Width - x)) iff X < Width.
// We limit this to X < Width in case the backend re-expands the
// intrinsic, and has to reintroduce a shift modulo operation (InstCombine
// might remove it after this fold). This still doesn't guarantee that the
// final codegen will match this original pattern.
if (match(R, m_OneUse(m_Sub(m_SpecificInt(Width), m_Specific(L))))) {
KnownBits KnownL = computeKnownBits(L, /*Depth*/ 0, &Or);
return KnownL.getMaxValue().ult(Width) ? L : nullptr;
}
// For non-constant cases, the following patterns currently only work for
// rotation patterns.
// TODO: Add general funnel-shift compatible patterns.
if (ShVal0 != ShVal1)
return nullptr;
// For non-constant cases we don't support non-pow2 shift masks.
// TODO: Is it worth matching urem as well?
if (!isPowerOf2_32(Width))
return nullptr;
// The shift amount may be masked with negation:
// (shl ShVal, (X & (Width - 1))) | (lshr ShVal, ((-X) & (Width - 1)))
Value *X;
unsigned Mask = Width - 1;
if (match(L, m_And(m_Value(X), m_SpecificInt(Mask))) &&
match(R, m_And(m_Neg(m_Specific(X)), m_SpecificInt(Mask))))
return X;
// (shl ShVal, X) | (lshr ShVal, ((-X) & (Width - 1)))
if (match(R, m_And(m_Neg(m_Specific(L)), m_SpecificInt(Mask))))
return L;
// Similar to above, but the shift amount may be extended after masking,
// so return the extended value as the parameter for the intrinsic.
if (match(L, m_ZExt(m_And(m_Value(X), m_SpecificInt(Mask)))) &&
match(R,
m_And(m_Neg(m_ZExt(m_And(m_Specific(X), m_SpecificInt(Mask)))),
m_SpecificInt(Mask))))
return L;
if (match(L, m_ZExt(m_And(m_Value(X), m_SpecificInt(Mask)))) &&
match(R, m_ZExt(m_And(m_Neg(m_Specific(X)), m_SpecificInt(Mask)))))
return L;
return nullptr;
};
Value *ShAmt = matchShiftAmount(ShAmt0, ShAmt1, Width);
if (!ShAmt) {
ShAmt = matchShiftAmount(ShAmt1, ShAmt0, Width);
IsFshl = false; // Sub on SHL.
}
if (!ShAmt)
return std::nullopt;
FShiftArgs = {ShVal0, ShVal1, ShAmt};
} else if (isa<ZExtInst>(Or0) || isa<ZExtInst>(Or1)) {
// If there are two 'or' instructions concat variables in opposite order:
//
// Slot1 and Slot2 are all zero bits.
// | Slot1 | Low | Slot2 | High |
// LowHigh = or (shl (zext Low), ZextLowShlAmt), (zext High)
// | Slot2 | High | Slot1 | Low |
// HighLow = or (shl (zext High), ZextHighShlAmt), (zext Low)
//
// the latter 'or' can be safely convert to
// -> HighLow = fshl LowHigh, LowHigh, ZextHighShlAmt
// if ZextLowShlAmt + ZextHighShlAmt == Width.
if (!isa<ZExtInst>(Or1))
std::swap(Or0, Or1);
Value *High, *ZextHigh, *Low;
const APInt *ZextHighShlAmt;
if (!match(Or0,
m_OneUse(m_Shl(m_Value(ZextHigh), m_APInt(ZextHighShlAmt)))))
return std::nullopt;
if (!match(Or1, m_ZExt(m_Value(Low))) ||
!match(ZextHigh, m_ZExt(m_Value(High))))
return std::nullopt;
unsigned HighSize = High->getType()->getScalarSizeInBits();
unsigned LowSize = Low->getType()->getScalarSizeInBits();
// Make sure High does not overlap with Low and most significant bits of
// High aren't shifted out.
if (ZextHighShlAmt->ult(LowSize) || ZextHighShlAmt->ugt(Width - HighSize))
return std::nullopt;
for (User *U : ZextHigh->users()) {
Value *X, *Y;
if (!match(U, m_Or(m_Value(X), m_Value(Y))))
continue;
if (!isa<ZExtInst>(Y))
std::swap(X, Y);
const APInt *ZextLowShlAmt;
if (!match(X, m_Shl(m_Specific(Or1), m_APInt(ZextLowShlAmt))) ||
!match(Y, m_Specific(ZextHigh)) || !DT.dominates(U, &Or))
continue;
// HighLow is good concat. If sum of two shifts amount equals to Width,
// LowHigh must also be a good concat.
if (*ZextLowShlAmt + *ZextHighShlAmt != Width)
continue;
// Low must not overlap with High and most significant bits of Low must
// not be shifted out.
assert(ZextLowShlAmt->uge(HighSize) &&
ZextLowShlAmt->ule(Width - LowSize) && "Invalid concat");
FShiftArgs = {U, U, ConstantInt::get(Or0->getType(), *ZextHighShlAmt)};
break;
}
}
if (FShiftArgs.empty())
return std::nullopt;
Intrinsic::ID IID = IsFshl ? Intrinsic::fshl : Intrinsic::fshr;
return std::make_pair(IID, FShiftArgs);
}
/// Match UB-safe variants of the funnel shift intrinsic.
static Instruction *matchFunnelShift(Instruction &Or, InstCombinerImpl &IC) {
if (auto Opt = IC.convertOrOfShiftsToFunnelShift(Or)) {
auto [IID, FShiftArgs] = *Opt;
Function *F =
Intrinsic::getOrInsertDeclaration(Or.getModule(), IID, Or.getType());
return CallInst::Create(F, FShiftArgs);
}
return nullptr;
}
/// Attempt to combine or(zext(x),shl(zext(y),bw/2) concat packing patterns.
static Instruction *matchOrConcat(Instruction &Or,
InstCombiner::BuilderTy &Builder) {
assert(Or.getOpcode() == Instruction::Or && "bswap requires an 'or'");
Value *Op0 = Or.getOperand(0), *Op1 = Or.getOperand(1);
Type *Ty = Or.getType();
unsigned Width = Ty->getScalarSizeInBits();
if ((Width & 1) != 0)
return nullptr;
unsigned HalfWidth = Width / 2;
// Canonicalize zext (lower half) to LHS.
if (!isa<ZExtInst>(Op0))
std::swap(Op0, Op1);
// Find lower/upper half.
Value *LowerSrc, *ShlVal, *UpperSrc;
const APInt *C;
if (!match(Op0, m_OneUse(m_ZExt(m_Value(LowerSrc)))) ||
!match(Op1, m_OneUse(m_Shl(m_Value(ShlVal), m_APInt(C)))) ||
!match(ShlVal, m_OneUse(m_ZExt(m_Value(UpperSrc)))))
return nullptr;
if (*C != HalfWidth || LowerSrc->getType() != UpperSrc->getType() ||
LowerSrc->getType()->getScalarSizeInBits() != HalfWidth)
return nullptr;
auto ConcatIntrinsicCalls = [&](Intrinsic::ID id, Value *Lo, Value *Hi) {
Value *NewLower = Builder.CreateZExt(Lo, Ty);
Value *NewUpper = Builder.CreateZExt(Hi, Ty);
NewUpper = Builder.CreateShl(NewUpper, HalfWidth);
Value *BinOp = Builder.CreateOr(NewLower, NewUpper);
return Builder.CreateIntrinsic(id, Ty, BinOp);
};
// BSWAP: Push the concat down, swapping the lower/upper sources.
// concat(bswap(x),bswap(y)) -> bswap(concat(x,y))
Value *LowerBSwap, *UpperBSwap;
if (match(LowerSrc, m_BSwap(m_Value(LowerBSwap))) &&
match(UpperSrc, m_BSwap(m_Value(UpperBSwap))))
return ConcatIntrinsicCalls(Intrinsic::bswap, UpperBSwap, LowerBSwap);
// BITREVERSE: Push the concat down, swapping the lower/upper sources.
// concat(bitreverse(x),bitreverse(y)) -> bitreverse(concat(x,y))
Value *LowerBRev, *UpperBRev;
if (match(LowerSrc, m_BitReverse(m_Value(LowerBRev))) &&
match(UpperSrc, m_BitReverse(m_Value(UpperBRev))))
return ConcatIntrinsicCalls(Intrinsic::bitreverse, UpperBRev, LowerBRev);
return nullptr;
}
/// If all elements of two constant vectors are 0/-1 and inverses, return true.
static bool areInverseVectorBitmasks(Constant *C1, Constant *C2) {
unsigned NumElts = cast<FixedVectorType>(C1->getType())->getNumElements();
for (unsigned i = 0; i != NumElts; ++i) {
Constant *EltC1 = C1->getAggregateElement(i);
Constant *EltC2 = C2->getAggregateElement(i);
if (!EltC1 || !EltC2)
return false;
// One element must be all ones, and the other must be all zeros.
if (!((match(EltC1, m_Zero()) && match(EltC2, m_AllOnes())) ||
(match(EltC2, m_Zero()) && match(EltC1, m_AllOnes()))))
return false;
}
return true;
}
/// We have an expression of the form (A & C) | (B & D). If A is a scalar or
/// vector composed of all-zeros or all-ones values and is the bitwise 'not' of
/// B, it can be used as the condition operand of a select instruction.
/// We will detect (A & C) | ~(B | D) when the flag ABIsTheSame enabled.
Value *InstCombinerImpl::getSelectCondition(Value *A, Value *B,
bool ABIsTheSame) {
// We may have peeked through bitcasts in the caller.
// Exit immediately if we don't have (vector) integer types.
Type *Ty = A->getType();
if (!Ty->isIntOrIntVectorTy() || !B->getType()->isIntOrIntVectorTy())
return nullptr;
// If A is the 'not' operand of B and has enough signbits, we have our answer.
if (ABIsTheSame ? (A == B) : match(B, m_Not(m_Specific(A)))) {
// If these are scalars or vectors of i1, A can be used directly.
if (Ty->isIntOrIntVectorTy(1))
return A;
// If we look through a vector bitcast, the caller will bitcast the operands
// to match the condition's number of bits (N x i1).
// To make this poison-safe, disallow bitcast from wide element to narrow
// element. That could allow poison in lanes where it was not present in the
// original code.
A = peekThroughBitcast(A);
if (A->getType()->isIntOrIntVectorTy()) {
unsigned NumSignBits = ComputeNumSignBits(A);
if (NumSignBits == A->getType()->getScalarSizeInBits() &&
NumSignBits <= Ty->getScalarSizeInBits())
return Builder.CreateTrunc(A, CmpInst::makeCmpResultType(A->getType()));
}
return nullptr;
}
// TODO: add support for sext and constant case
if (ABIsTheSame)
return nullptr;
// If both operands are constants, see if the constants are inverse bitmasks.
Constant *AConst, *BConst;
if (match(A, m_Constant(AConst)) && match(B, m_Constant(BConst)))
if (AConst == ConstantExpr::getNot(BConst) &&
ComputeNumSignBits(A) == Ty->getScalarSizeInBits())
return Builder.CreateZExtOrTrunc(A, CmpInst::makeCmpResultType(Ty));
// Look for more complex patterns. The 'not' op may be hidden behind various
// casts. Look through sexts and bitcasts to find the booleans.
Value *Cond;
Value *NotB;
if (match(A, m_SExt(m_Value(Cond))) &&
Cond->getType()->isIntOrIntVectorTy(1)) {
// A = sext i1 Cond; B = sext (not (i1 Cond))
if (match(B, m_SExt(m_Not(m_Specific(Cond)))))
return Cond;
// A = sext i1 Cond; B = not ({bitcast} (sext (i1 Cond)))
// TODO: The one-use checks are unnecessary or misplaced. If the caller
// checked for uses on logic ops/casts, that should be enough to
// make this transform worthwhile.
if (match(B, m_OneUse(m_Not(m_Value(NotB))))) {
NotB = peekThroughBitcast(NotB, true);
if (match(NotB, m_SExt(m_Specific(Cond))))
return Cond;
}
}
// All scalar (and most vector) possibilities should be handled now.
// Try more matches that only apply to non-splat constant vectors.
if (!Ty->isVectorTy())
return nullptr;
// If both operands are xor'd with constants using the same sexted boolean
// operand, see if the constants are inverse bitmasks.
// TODO: Use ConstantExpr::getNot()?
if (match(A, (m_Xor(m_SExt(m_Value(Cond)), m_Constant(AConst)))) &&
match(B, (m_Xor(m_SExt(m_Specific(Cond)), m_Constant(BConst)))) &&
Cond->getType()->isIntOrIntVectorTy(1) &&
areInverseVectorBitmasks(AConst, BConst)) {
AConst = ConstantExpr::getTrunc(AConst, CmpInst::makeCmpResultType(Ty));
return Builder.CreateXor(Cond, AConst);
}
return nullptr;
}
/// We have an expression of the form (A & B) | (C & D). Try to simplify this
/// to "A' ? B : D", where A' is a boolean or vector of booleans.
/// When InvertFalseVal is set to true, we try to match the pattern
/// where we have peeked through a 'not' op and A and C are the same:
/// (A & B) | ~(A | D) --> (A & B) | (~A & ~D) --> A' ? B : ~D
Value *InstCombinerImpl::matchSelectFromAndOr(Value *A, Value *B, Value *C,
Value *D, bool InvertFalseVal) {
// The potential condition of the select may be bitcasted. In that case, look
// through its bitcast and the corresponding bitcast of the 'not' condition.
Type *OrigType = A->getType();
A = peekThroughBitcast(A, true);
C = peekThroughBitcast(C, true);
if (Value *Cond = getSelectCondition(A, C, InvertFalseVal)) {
// ((bc Cond) & B) | ((bc ~Cond) & D) --> bc (select Cond, (bc B), (bc D))
// If this is a vector, we may need to cast to match the condition's length.
// The bitcasts will either all exist or all not exist. The builder will
// not create unnecessary casts if the types already match.
Type *SelTy = A->getType();
if (auto *VecTy = dyn_cast<VectorType>(Cond->getType())) {
// For a fixed or scalable vector get N from <{vscale x} N x iM>
unsigned Elts = VecTy->getElementCount().getKnownMinValue();
// For a fixed or scalable vector, get the size in bits of N x iM; for a
// scalar this is just M.
unsigned SelEltSize = SelTy->getPrimitiveSizeInBits().getKnownMinValue();
Type *EltTy = Builder.getIntNTy(SelEltSize / Elts);
SelTy = VectorType::get(EltTy, VecTy->getElementCount());
}
Value *BitcastB = Builder.CreateBitCast(B, SelTy);
if (InvertFalseVal)
D = Builder.CreateNot(D);
Value *BitcastD = Builder.CreateBitCast(D, SelTy);
Value *Select = Builder.CreateSelect(Cond, BitcastB, BitcastD);
return Builder.CreateBitCast(Select, OrigType);
}
return nullptr;
}
// (icmp eq X, C) | (icmp ult Other, (X - C)) -> (icmp ule Other, (X - (C + 1)))
// (icmp ne X, C) & (icmp uge Other, (X - C)) -> (icmp ugt Other, (X - (C + 1)))
static Value *foldAndOrOfICmpEqConstantAndICmp(ICmpInst *LHS, ICmpInst *RHS,
bool IsAnd, bool IsLogical,
IRBuilderBase &Builder) {
Value *LHS0 = LHS->getOperand(0);
Value *RHS0 = RHS->getOperand(0);
Value *RHS1 = RHS->getOperand(1);
ICmpInst::Predicate LPred =
IsAnd ? LHS->getInversePredicate() : LHS->getPredicate();
ICmpInst::Predicate RPred =
IsAnd ? RHS->getInversePredicate() : RHS->getPredicate();
const APInt *CInt;
if (LPred != ICmpInst::ICMP_EQ ||
!match(LHS->getOperand(1), m_APIntAllowPoison(CInt)) ||
!LHS0->getType()->isIntOrIntVectorTy() ||
!(LHS->hasOneUse() || RHS->hasOneUse()))
return nullptr;
auto MatchRHSOp = [LHS0, CInt](const Value *RHSOp) {
return match(RHSOp,
m_Add(m_Specific(LHS0), m_SpecificIntAllowPoison(-*CInt))) ||
(CInt->isZero() && RHSOp == LHS0);
};
Value *Other;
if (RPred == ICmpInst::ICMP_ULT && MatchRHSOp(RHS1))
Other = RHS0;
else if (RPred == ICmpInst::ICMP_UGT && MatchRHSOp(RHS0))
Other = RHS1;
else
return nullptr;
if (IsLogical)
Other = Builder.CreateFreeze(Other);
return Builder.CreateICmp(
IsAnd ? ICmpInst::ICMP_ULT : ICmpInst::ICMP_UGE,
Builder.CreateSub(LHS0, ConstantInt::get(LHS0->getType(), *CInt + 1)),
Other);
}
/// Fold (icmp)&(icmp) or (icmp)|(icmp) if possible.
/// If IsLogical is true, then the and/or is in select form and the transform
/// must be poison-safe.
Value *InstCombinerImpl::foldAndOrOfICmps(ICmpInst *LHS, ICmpInst *RHS,
Instruction &I, bool IsAnd,
bool IsLogical) {
const SimplifyQuery Q = SQ.getWithInstruction(&I);
ICmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
Value *LHS0 = LHS->getOperand(0), *RHS0 = RHS->getOperand(0);
Value *LHS1 = LHS->getOperand(1), *RHS1 = RHS->getOperand(1);
const APInt *LHSC = nullptr, *RHSC = nullptr;
match(LHS1, m_APInt(LHSC));
match(RHS1, m_APInt(RHSC));
// (icmp1 A, B) | (icmp2 A, B) --> (icmp3 A, B)
// (icmp1 A, B) & (icmp2 A, B) --> (icmp3 A, B)
if (predicatesFoldable(PredL, PredR)) {
if (LHS0 == RHS1 && LHS1 == RHS0) {
PredL = ICmpInst::getSwappedPredicate(PredL);
std::swap(LHS0, LHS1);
}
if (LHS0 == RHS0 && LHS1 == RHS1) {
unsigned Code = IsAnd ? getICmpCode(PredL) & getICmpCode(PredR)
: getICmpCode(PredL) | getICmpCode(PredR);
bool IsSigned = LHS->isSigned() || RHS->isSigned();
return getNewICmpValue(Code, IsSigned, LHS0, LHS1, Builder);
}
}
// handle (roughly):
// (icmp ne (A & B), C) | (icmp ne (A & D), E)
// (icmp eq (A & B), C) & (icmp eq (A & D), E)
if (Value *V = foldLogOpOfMaskedICmps(LHS, RHS, IsAnd, IsLogical, Builder, Q))
return V;
if (Value *V =
foldAndOrOfICmpEqConstantAndICmp(LHS, RHS, IsAnd, IsLogical, Builder))
return V;
// We can treat logical like bitwise here, because both operands are used on
// the LHS, and as such poison from both will propagate.
if (Value *V = foldAndOrOfICmpEqConstantAndICmp(RHS, LHS, IsAnd,
/*IsLogical*/ false, Builder))
return V;
if (Value *V =
foldAndOrOfICmpsWithConstEq(LHS, RHS, IsAnd, IsLogical, Builder, Q))
return V;
// We can convert this case to bitwise and, because both operands are used
// on the LHS, and as such poison from both will propagate.
if (Value *V = foldAndOrOfICmpsWithConstEq(RHS, LHS, IsAnd,
/*IsLogical=*/false, Builder, Q)) {
// If RHS is still used, we should drop samesign flag.
if (IsLogical && RHS->hasSameSign() && !RHS->use_empty()) {
RHS->setSameSign(false);
addToWorklist(RHS);
}
return V;
}
if (Value *V = foldIsPowerOf2OrZero(LHS, RHS, IsAnd, Builder, *this))
return V;
if (Value *V = foldIsPowerOf2OrZero(RHS, LHS, IsAnd, Builder, *this))
return V;
// TODO: One of these directions is fine with logical and/or, the other could
// be supported by inserting freeze.
if (!IsLogical) {
// E.g. (icmp slt x, 0) | (icmp sgt x, n) --> icmp ugt x, n
// E.g. (icmp sge x, 0) & (icmp slt x, n) --> icmp ult x, n
if (Value *V = simplifyRangeCheck(LHS, RHS, /*Inverted=*/!IsAnd))
return V;
// E.g. (icmp sgt x, n) | (icmp slt x, 0) --> icmp ugt x, n
// E.g. (icmp slt x, n) & (icmp sge x, 0) --> icmp ult x, n
if (Value *V = simplifyRangeCheck(RHS, LHS, /*Inverted=*/!IsAnd))
return V;
}
// TODO: Add conjugated or fold, check whether it is safe for logical and/or.
if (IsAnd && !IsLogical)
if (Value *V = foldSignedTruncationCheck(LHS, RHS, I, Builder))
return V;
if (Value *V = foldIsPowerOf2(LHS, RHS, IsAnd, Builder, *this))
return V;
if (Value *V = foldPowerOf2AndShiftedMask(LHS, RHS, IsAnd, Builder))
return V;
// TODO: Verify whether this is safe for logical and/or.
if (!IsLogical) {
if (Value *X = foldUnsignedUnderflowCheck(LHS, RHS, IsAnd, Q, Builder))
return X;
if (Value *X = foldUnsignedUnderflowCheck(RHS, LHS, IsAnd, Q, Builder))
return X;
}
// (icmp ne A, 0) | (icmp ne B, 0) --> (icmp ne (A|B), 0)
// (icmp eq A, 0) & (icmp eq B, 0) --> (icmp eq (A|B), 0)
// TODO: Remove this and below when foldLogOpOfMaskedICmps can handle undefs.
if (PredL == (IsAnd ? ICmpInst::ICMP_EQ : ICmpInst::ICMP_NE) &&
PredL == PredR && match(LHS1, m_ZeroInt()) && match(RHS1, m_ZeroInt()) &&
LHS0->getType() == RHS0->getType() &&
(!IsLogical || isGuaranteedNotToBePoison(RHS0))) {
Value *NewOr = Builder.CreateOr(LHS0, RHS0);
return Builder.CreateICmp(PredL, NewOr,
Constant::getNullValue(NewOr->getType()));
}
// (icmp ne A, -1) | (icmp ne B, -1) --> (icmp ne (A&B), -1)
// (icmp eq A, -1) & (icmp eq B, -1) --> (icmp eq (A&B), -1)
if (PredL == (IsAnd ? ICmpInst::ICMP_EQ : ICmpInst::ICMP_NE) &&
PredL == PredR && match(LHS1, m_AllOnes()) && match(RHS1, m_AllOnes()) &&
LHS0->getType() == RHS0->getType() &&
(!IsLogical || isGuaranteedNotToBePoison(RHS0))) {
Value *NewAnd = Builder.CreateAnd(LHS0, RHS0);
return Builder.CreateICmp(PredL, NewAnd,
Constant::getAllOnesValue(LHS0->getType()));
}
if (!IsLogical)
if (Value *V =
foldAndOrOfICmpsWithPow2AndWithZero(Builder, LHS, RHS, IsAnd, Q))
return V;
// This only handles icmp of constants: (icmp1 A, C1) | (icmp2 B, C2).
if (!LHSC || !RHSC)
return nullptr;
// (trunc x) == C1 & (and x, CA) == C2 -> (and x, CA|CMAX) == C1|C2
// (trunc x) != C1 | (and x, CA) != C2 -> (and x, CA|CMAX) != C1|C2
// where CMAX is the all ones value for the truncated type,
// iff the lower bits of C2 and CA are zero.
if (PredL == (IsAnd ? ICmpInst::ICMP_EQ : ICmpInst::ICMP_NE) &&
PredL == PredR && LHS->hasOneUse() && RHS->hasOneUse()) {
Value *V;
const APInt *AndC, *SmallC = nullptr, *BigC = nullptr;
// (trunc x) == C1 & (and x, CA) == C2
// (and x, CA) == C2 & (trunc x) == C1
if (match(RHS0, m_Trunc(m_Value(V))) &&
match(LHS0, m_And(m_Specific(V), m_APInt(AndC)))) {
SmallC = RHSC;
BigC = LHSC;
} else if (match(LHS0, m_Trunc(m_Value(V))) &&
match(RHS0, m_And(m_Specific(V), m_APInt(AndC)))) {
SmallC = LHSC;
BigC = RHSC;
}
if (SmallC && BigC) {
unsigned BigBitSize = BigC->getBitWidth();
unsigned SmallBitSize = SmallC->getBitWidth();
// Check that the low bits are zero.
APInt Low = APInt::getLowBitsSet(BigBitSize, SmallBitSize);
if ((Low & *AndC).isZero() && (Low & *BigC).isZero()) {
Value *NewAnd = Builder.CreateAnd(V, Low | *AndC);
APInt N = SmallC->zext(BigBitSize) | *BigC;
Value *NewVal = ConstantInt::get(NewAnd->getType(), N);
return Builder.CreateICmp(PredL, NewAnd, NewVal);
}
}
}
// Match naive pattern (and its inverted form) for checking if two values
// share same sign. An example of the pattern:
// (icmp slt (X & Y), 0) | (icmp sgt (X | Y), -1) -> (icmp sgt (X ^ Y), -1)
// Inverted form (example):
// (icmp slt (X | Y), 0) & (icmp sgt (X & Y), -1) -> (icmp slt (X ^ Y), 0)
bool TrueIfSignedL, TrueIfSignedR;
if (isSignBitCheck(PredL, *LHSC, TrueIfSignedL) &&
isSignBitCheck(PredR, *RHSC, TrueIfSignedR) &&
(RHS->hasOneUse() || LHS->hasOneUse())) {
Value *X, *Y;
if (IsAnd) {
if ((TrueIfSignedL && !TrueIfSignedR &&
match(LHS0, m_Or(m_Value(X), m_Value(Y))) &&
match(RHS0, m_c_And(m_Specific(X), m_Specific(Y)))) ||
(!TrueIfSignedL && TrueIfSignedR &&
match(LHS0, m_And(m_Value(X), m_Value(Y))) &&
match(RHS0, m_c_Or(m_Specific(X), m_Specific(Y))))) {
Value *NewXor = Builder.CreateXor(X, Y);
return Builder.CreateIsNeg(NewXor);
}
} else {
if ((TrueIfSignedL && !TrueIfSignedR &&
match(LHS0, m_And(m_Value(X), m_Value(Y))) &&
match(RHS0, m_c_Or(m_Specific(X), m_Specific(Y)))) ||
(!TrueIfSignedL && TrueIfSignedR &&
match(LHS0, m_Or(m_Value(X), m_Value(Y))) &&
match(RHS0, m_c_And(m_Specific(X), m_Specific(Y))))) {
Value *NewXor = Builder.CreateXor(X, Y);
return Builder.CreateIsNotNeg(NewXor);
}
}
}
return foldAndOrOfICmpsUsingRanges(LHS, RHS, IsAnd);
}
/// If IsLogical is true, then the and/or is in select form and the transform
/// must be poison-safe.
Value *InstCombinerImpl::foldBooleanAndOr(Value *LHS, Value *RHS,
Instruction &I, bool IsAnd,
bool IsLogical) {
if (!LHS->getType()->isIntOrIntVectorTy(1))
return nullptr;
if (auto *LHSCmp = dyn_cast<ICmpInst>(LHS))
if (auto *RHSCmp = dyn_cast<ICmpInst>(RHS))
if (Value *Res = foldAndOrOfICmps(LHSCmp, RHSCmp, I, IsAnd, IsLogical))
return Res;
if (auto *LHSCmp = dyn_cast<FCmpInst>(LHS))
if (auto *RHSCmp = dyn_cast<FCmpInst>(RHS))
if (Value *Res = foldLogicOfFCmps(LHSCmp, RHSCmp, IsAnd, IsLogical))
return Res;
if (Value *Res = foldEqOfParts(LHS, RHS, IsAnd))
return Res;
return nullptr;
}
static Value *foldOrOfInversions(BinaryOperator &I,
InstCombiner::BuilderTy &Builder) {
assert(I.getOpcode() == Instruction::Or &&
"Simplification only supports or at the moment.");
Value *Cmp1, *Cmp2, *Cmp3, *Cmp4;
if (!match(I.getOperand(0), m_And(m_Value(Cmp1), m_Value(Cmp2))) ||
!match(I.getOperand(1), m_And(m_Value(Cmp3), m_Value(Cmp4))))
return nullptr;
// Check if any two pairs of the and operations are inversions of each other.
if (isKnownInversion(Cmp1, Cmp3) && isKnownInversion(Cmp2, Cmp4))
return Builder.CreateXor(Cmp1, Cmp4);
if (isKnownInversion(Cmp1, Cmp4) && isKnownInversion(Cmp2, Cmp3))
return Builder.CreateXor(Cmp1, Cmp3);
return nullptr;
}
// FIXME: We use commutative matchers (m_c_*) for some, but not all, matches
// here. We should standardize that construct where it is needed or choose some
// other way to ensure that commutated variants of patterns are not missed.
Instruction *InstCombinerImpl::visitOr(BinaryOperator &I) {
if (Value *V = simplifyOrInst(I.getOperand(0), I.getOperand(1),
SQ.getWithInstruction(&I)))
return replaceInstUsesWith(I, V);
if (SimplifyAssociativeOrCommutative(I))
return &I;
if (Instruction *X = foldVectorBinop(I))
return X;
if (Instruction *Phi = foldBinopWithPhiOperands(I))
return Phi;
// See if we can simplify any instructions used by the instruction whose sole
// purpose is to compute bits we don't care about.
if (SimplifyDemandedInstructionBits(I))
return &I;
// Do this before using distributive laws to catch simple and/or/not patterns.
if (Instruction *Xor = foldOrToXor(I, Builder))
return Xor;
if (Instruction *X = foldComplexAndOrPatterns(I, Builder))
return X;
// (A & B) | (C & D) -> A ^ D where A == ~C && B == ~D
// (A & B) | (C & D) -> A ^ C where A == ~D && B == ~C
if (Value *V = foldOrOfInversions(I, Builder))
return replaceInstUsesWith(I, V);
// (A&B)|(A&C) -> A&(B|C) etc
if (Value *V = foldUsingDistributiveLaws(I))
return replaceInstUsesWith(I, V);
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
Type *Ty = I.getType();
if (Ty->isIntOrIntVectorTy(1)) {
if (auto *SI0 = dyn_cast<SelectInst>(Op0)) {
if (auto *R =
foldAndOrOfSelectUsingImpliedCond(Op1, *SI0, /* IsAnd */ false))
return R;
}
if (auto *SI1 = dyn_cast<SelectInst>(Op1)) {
if (auto *R =
foldAndOrOfSelectUsingImpliedCond(Op0, *SI1, /* IsAnd */ false))
return R;
}
}
if (Instruction *FoldedLogic = foldBinOpIntoSelectOrPhi(I))
return FoldedLogic;
if (Instruction *BitOp = matchBSwapOrBitReverse(I, /*MatchBSwaps*/ true,
/*MatchBitReversals*/ true))
return BitOp;
if (Instruction *Funnel = matchFunnelShift(I, *this))
return Funnel;
if (Instruction *Concat = matchOrConcat(I, Builder))
return replaceInstUsesWith(I, Concat);
if (Instruction *R = foldBinOpShiftWithShift(I))
return R;
if (Instruction *R = tryFoldInstWithCtpopWithNot(&I))
return R;
if (cast<PossiblyDisjointInst>(I).isDisjoint()) {
if (Instruction *R =
foldAddLikeCommutative(I.getOperand(0), I.getOperand(1),
/*NSW=*/true, /*NUW=*/true))
return R;
if (Instruction *R =
foldAddLikeCommutative(I.getOperand(1), I.getOperand(0),
/*NSW=*/true, /*NUW=*/true))
return R;
}
Value *X, *Y;
const APInt *CV;
if (match(&I, m_c_Or(m_OneUse(m_Xor(m_Value(X), m_APInt(CV))), m_Value(Y))) &&
!CV->isAllOnes() && MaskedValueIsZero(Y, *CV, 0, &I)) {
// (X ^ C) | Y -> (X | Y) ^ C iff Y & C == 0
// The check for a 'not' op is for efficiency (if Y is known zero --> ~X).
Value *Or = Builder.CreateOr(X, Y);
return BinaryOperator::CreateXor(Or, ConstantInt::get(Ty, *CV));
}
// If the operands have no common bits set:
// or (mul X, Y), X --> add (mul X, Y), X --> mul X, (Y + 1)
if (match(&I, m_c_DisjointOr(m_OneUse(m_Mul(m_Value(X), m_Value(Y))),
m_Deferred(X)))) {
Value *IncrementY = Builder.CreateAdd(Y, ConstantInt::get(Ty, 1));
return BinaryOperator::CreateMul(X, IncrementY);
}
// (A & C) | (B & D)
Value *A, *B, *C, *D;
if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
match(Op1, m_And(m_Value(B), m_Value(D)))) {
// (A & C0) | (B & C1)
const APInt *C0, *C1;
if (match(C, m_APInt(C0)) && match(D, m_APInt(C1))) {
Value *X;
if (*C0 == ~*C1) {
// ((X | B) & MaskC) | (B & ~MaskC) -> (X & MaskC) | B
if (match(A, m_c_Or(m_Value(X), m_Specific(B))))
return BinaryOperator::CreateOr(Builder.CreateAnd(X, *C0), B);
// (A & MaskC) | ((X | A) & ~MaskC) -> (X & ~MaskC) | A
if (match(B, m_c_Or(m_Specific(A), m_Value(X))))
return BinaryOperator::CreateOr(Builder.CreateAnd(X, *C1), A);
// ((X ^ B) & MaskC) | (B & ~MaskC) -> (X & MaskC) ^ B
if (match(A, m_c_Xor(m_Value(X), m_Specific(B))))
return BinaryOperator::CreateXor(Builder.CreateAnd(X, *C0), B);
// (A & MaskC) | ((X ^ A) & ~MaskC) -> (X & ~MaskC) ^ A
if (match(B, m_c_Xor(m_Specific(A), m_Value(X))))
return BinaryOperator::CreateXor(Builder.CreateAnd(X, *C1), A);
}
if ((*C0 & *C1).isZero()) {
// ((X | B) & C0) | (B & C1) --> (X | B) & (C0 | C1)
// iff (C0 & C1) == 0 and (X & ~C0) == 0
if (match(A, m_c_Or(m_Value(X), m_Specific(B))) &&
MaskedValueIsZero(X, ~*C0, 0, &I)) {
Constant *C01 = ConstantInt::get(Ty, *C0 | *C1);
return BinaryOperator::CreateAnd(A, C01);
}
// (A & C0) | ((X | A) & C1) --> (X | A) & (C0 | C1)
// iff (C0 & C1) == 0 and (X & ~C1) == 0
if (match(B, m_c_Or(m_Value(X), m_Specific(A))) &&
MaskedValueIsZero(X, ~*C1, 0, &I)) {
Constant *C01 = ConstantInt::get(Ty, *C0 | *C1);
return BinaryOperator::CreateAnd(B, C01);
}
// ((X | C2) & C0) | ((X | C3) & C1) --> (X | C2 | C3) & (C0 | C1)
// iff (C0 & C1) == 0 and (C2 & ~C0) == 0 and (C3 & ~C1) == 0.
const APInt *C2, *C3;
if (match(A, m_Or(m_Value(X), m_APInt(C2))) &&
match(B, m_Or(m_Specific(X), m_APInt(C3))) &&
(*C2 & ~*C0).isZero() && (*C3 & ~*C1).isZero()) {
Value *Or = Builder.CreateOr(X, *C2 | *C3, "bitfield");
Constant *C01 = ConstantInt::get(Ty, *C0 | *C1);
return BinaryOperator::CreateAnd(Or, C01);
}
}
}
// Don't try to form a select if it's unlikely that we'll get rid of at
// least one of the operands. A select is generally more expensive than the
// 'or' that it is replacing.
if (Op0->hasOneUse() || Op1->hasOneUse()) {
// (Cond & C) | (~Cond & D) -> Cond ? C : D, and commuted variants.
if (Value *V = matchSelectFromAndOr(A, C, B, D))
return replaceInstUsesWith(I, V);
if (Value *V = matchSelectFromAndOr(A, C, D, B))
return replaceInstUsesWith(I, V);
if (Value *V = matchSelectFromAndOr(C, A, B, D))
return replaceInstUsesWith(I, V);
if (Value *V = matchSelectFromAndOr(C, A, D, B))
return replaceInstUsesWith(I, V);
if (Value *V = matchSelectFromAndOr(B, D, A, C))
return replaceInstUsesWith(I, V);
if (Value *V = matchSelectFromAndOr(B, D, C, A))
return replaceInstUsesWith(I, V);
if (Value *V = matchSelectFromAndOr(D, B, A, C))
return replaceInstUsesWith(I, V);
if (Value *V = matchSelectFromAndOr(D, B, C, A))
return replaceInstUsesWith(I, V);
}
}
if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
match(Op1, m_Not(m_Or(m_Value(B), m_Value(D)))) &&
(Op0->hasOneUse() || Op1->hasOneUse())) {
// (Cond & C) | ~(Cond | D) -> Cond ? C : ~D
if (Value *V = matchSelectFromAndOr(A, C, B, D, true))
return replaceInstUsesWith(I, V);
if (Value *V = matchSelectFromAndOr(A, C, D, B, true))
return replaceInstUsesWith(I, V);
if (Value *V = matchSelectFromAndOr(C, A, B, D, true))
return replaceInstUsesWith(I, V);
if (Value *V = matchSelectFromAndOr(C, A, D, B, true))
return replaceInstUsesWith(I, V);
}
// (A ^ B) | ((B ^ C) ^ A) -> (A ^ B) | C
if (match(Op0, m_Xor(m_Value(A), m_Value(B))))
if (match(Op1,
m_c_Xor(m_c_Xor(m_Specific(B), m_Value(C)), m_Specific(A))) ||
match(Op1, m_c_Xor(m_c_Xor(m_Specific(A), m_Value(C)), m_Specific(B))))
return BinaryOperator::CreateOr(Op0, C);
// ((B ^ C) ^ A) | (A ^ B) -> (A ^ B) | C
if (match(Op1, m_Xor(m_Value(A), m_Value(B))))
if (match(Op0,
m_c_Xor(m_c_Xor(m_Specific(B), m_Value(C)), m_Specific(A))) ||
match(Op0, m_c_Xor(m_c_Xor(m_Specific(A), m_Value(C)), m_Specific(B))))
return BinaryOperator::CreateOr(Op1, C);
if (Instruction *DeMorgan = matchDeMorgansLaws(I, *this))
return DeMorgan;
// Canonicalize xor to the RHS.
bool SwappedForXor = false;
if (match(Op0, m_Xor(m_Value(), m_Value()))) {
std::swap(Op0, Op1);
SwappedForXor = true;
}
if (match(Op1, m_Xor(m_Value(A), m_Value(B)))) {
// (A | ?) | (A ^ B) --> (A | ?) | B
// (B | ?) | (A ^ B) --> (B | ?) | A
if (match(Op0, m_c_Or(m_Specific(A), m_Value())))
return BinaryOperator::CreateOr(Op0, B);
if (match(Op0, m_c_Or(m_Specific(B), m_Value())))
return BinaryOperator::CreateOr(Op0, A);
// (A & B) | (A ^ B) --> A | B
// (B & A) | (A ^ B) --> A | B
if (match(Op0, m_c_And(m_Specific(A), m_Specific(B))))
return BinaryOperator::CreateOr(A, B);
// ~A | (A ^ B) --> ~(A & B)
// ~B | (A ^ B) --> ~(A & B)
// The swap above should always make Op0 the 'not'.
if ((Op0->hasOneUse() || Op1->hasOneUse()) &&
(match(Op0, m_Not(m_Specific(A))) || match(Op0, m_Not(m_Specific(B)))))
return BinaryOperator::CreateNot(Builder.CreateAnd(A, B));
// Same as above, but peek through an 'and' to the common operand:
// ~(A & ?) | (A ^ B) --> ~((A & ?) & B)
// ~(B & ?) | (A ^ B) --> ~((B & ?) & A)
Instruction *And;
if ((Op0->hasOneUse() || Op1->hasOneUse()) &&
match(Op0, m_Not(m_CombineAnd(m_Instruction(And),
m_c_And(m_Specific(A), m_Value())))))
return BinaryOperator::CreateNot(Builder.CreateAnd(And, B));
if ((Op0->hasOneUse() || Op1->hasOneUse()) &&
match(Op0, m_Not(m_CombineAnd(m_Instruction(And),
m_c_And(m_Specific(B), m_Value())))))
return BinaryOperator::CreateNot(Builder.CreateAnd(And, A));
// (~A | C) | (A ^ B) --> ~(A & B) | C
// (~B | C) | (A ^ B) --> ~(A & B) | C
if (Op0->hasOneUse() && Op1->hasOneUse() &&
(match(Op0, m_c_Or(m_Not(m_Specific(A)), m_Value(C))) ||
match(Op0, m_c_Or(m_Not(m_Specific(B)), m_Value(C))))) {
Value *Nand = Builder.CreateNot(Builder.CreateAnd(A, B), "nand");
return BinaryOperator::CreateOr(Nand, C);
}
}
if (SwappedForXor)
std::swap(Op0, Op1);
if (Value *Res =
foldBooleanAndOr(Op0, Op1, I, /*IsAnd=*/false, /*IsLogical=*/false))
return replaceInstUsesWith(I, Res);
if (match(Op1, m_OneUse(m_LogicalOr(m_Value(X), m_Value(Y))))) {
bool IsLogical = isa<SelectInst>(Op1);
if (auto *V = reassociateBooleanAndOr(Op0, X, Y, I, /*IsAnd=*/false,
/*RHSIsLogical=*/IsLogical))
return replaceInstUsesWith(I, V);
}
if (match(Op0, m_OneUse(m_LogicalOr(m_Value(X), m_Value(Y))))) {
bool IsLogical = isa<SelectInst>(Op0);
if (auto *V = reassociateBooleanAndOr(Op1, X, Y, I, /*IsAnd=*/false,
/*RHSIsLogical=*/IsLogical))
return replaceInstUsesWith(I, V);
}
if (Instruction *FoldedFCmps = reassociateFCmps(I, Builder))
return FoldedFCmps;
if (Instruction *CastedOr = foldCastedBitwiseLogic(I))
return CastedOr;
if (Instruction *Sel = foldBinopOfSextBoolToSelect(I))
return Sel;
// or(sext(A), B) / or(B, sext(A)) --> A ? -1 : B, where A is i1 or <N x i1>.
// TODO: Move this into foldBinopOfSextBoolToSelect as a more generalized fold
// with binop identity constant. But creating a select with non-constant
// arm may not be reversible due to poison semantics. Is that a good
// canonicalization?
if (match(&I, m_c_Or(m_OneUse(m_SExt(m_Value(A))), m_Value(B))) &&
A->getType()->isIntOrIntVectorTy(1))
return SelectInst::Create(A, ConstantInt::getAllOnesValue(Ty), B);
// Note: If we've gotten to the point of visiting the outer OR, then the
// inner one couldn't be simplified. If it was a constant, then it won't
// be simplified by a later pass either, so we try swapping the inner/outer
// ORs in the hopes that we'll be able to simplify it this way.
// (X|C) | V --> (X|V) | C
ConstantInt *CI;
if (Op0->hasOneUse() && !match(Op1, m_ConstantInt()) &&
match(Op0, m_Or(m_Value(A), m_ConstantInt(CI)))) {
Value *Inner = Builder.CreateOr(A, Op1);
Inner->takeName(Op0);
return BinaryOperator::CreateOr(Inner, CI);
}
// Change (or (bool?A:B),(bool?C:D)) --> (bool?(or A,C):(or B,D))
// Since this OR statement hasn't been optimized further yet, we hope
// that this transformation will allow the new ORs to be optimized.
{
Value *X = nullptr, *Y = nullptr;
if (Op0->hasOneUse() && Op1->hasOneUse() &&
match(Op0, m_Select(m_Value(X), m_Value(A), m_Value(B))) &&
match(Op1, m_Select(m_Value(Y), m_Value(C), m_Value(D))) && X == Y) {
Value *orTrue = Builder.CreateOr(A, C);
Value *orFalse = Builder.CreateOr(B, D);
return SelectInst::Create(X, orTrue, orFalse);
}
}
// or(ashr(subNSW(Y, X), ScalarSizeInBits(Y) - 1), X) --> X s> Y ? -1 : X.
{
Value *X, *Y;
if (match(&I, m_c_Or(m_OneUse(m_AShr(
m_NSWSub(m_Value(Y), m_Value(X)),
m_SpecificInt(Ty->getScalarSizeInBits() - 1))),
m_Deferred(X)))) {
Value *NewICmpInst = Builder.CreateICmpSGT(X, Y);
Value *AllOnes = ConstantInt::getAllOnesValue(Ty);
return SelectInst::Create(NewICmpInst, AllOnes, X);
}
}
{
// ((A & B) ^ A) | ((A & B) ^ B) -> A ^ B
// (A ^ (A & B)) | (B ^ (A & B)) -> A ^ B
// ((A & B) ^ B) | ((A & B) ^ A) -> A ^ B
// (B ^ (A & B)) | (A ^ (A & B)) -> A ^ B
const auto TryXorOpt = [&](Value *Lhs, Value *Rhs) -> Instruction * {
if (match(Lhs, m_c_Xor(m_And(m_Value(A), m_Value(B)), m_Deferred(A))) &&
match(Rhs,
m_c_Xor(m_And(m_Specific(A), m_Specific(B)), m_Specific(B)))) {
return BinaryOperator::CreateXor(A, B);
}
return nullptr;
};
if (Instruction *Result = TryXorOpt(Op0, Op1))
return Result;
if (Instruction *Result = TryXorOpt(Op1, Op0))
return Result;
}
if (Instruction *V =
canonicalizeCondSignextOfHighBitExtractToSignextHighBitExtract(I))
return V;
CmpPredicate Pred;
Value *Mul, *Ov, *MulIsNotZero, *UMulWithOv;
// Check if the OR weakens the overflow condition for umul.with.overflow by
// treating any non-zero result as overflow. In that case, we overflow if both
// umul.with.overflow operands are != 0, as in that case the result can only
// be 0, iff the multiplication overflows.
if (match(&I,
m_c_Or(m_CombineAnd(m_ExtractValue<1>(m_Value(UMulWithOv)),
m_Value(Ov)),
m_CombineAnd(
m_SpecificICmp(ICmpInst::ICMP_NE,
m_CombineAnd(m_ExtractValue<0>(
m_Deferred(UMulWithOv)),
m_Value(Mul)),
m_ZeroInt()),
m_Value(MulIsNotZero)))) &&
(Ov->hasOneUse() || (MulIsNotZero->hasOneUse() && Mul->hasOneUse()))) {
Value *A, *B;
if (match(UMulWithOv, m_Intrinsic<Intrinsic::umul_with_overflow>(
m_Value(A), m_Value(B)))) {
Value *NotNullA = Builder.CreateIsNotNull(A);
Value *NotNullB = Builder.CreateIsNotNull(B);
return BinaryOperator::CreateAnd(NotNullA, NotNullB);
}
}
/// Res, Overflow = xxx_with_overflow X, C1
/// Try to canonicalize the pattern "Overflow | icmp pred Res, C2" into
/// "Overflow | icmp pred X, C2 +/- C1".
const WithOverflowInst *WO;
const Value *WOV;
const APInt *C1, *C2;
if (match(&I, m_c_Or(m_CombineAnd(m_ExtractValue<1>(m_CombineAnd(
m_WithOverflowInst(WO), m_Value(WOV))),
m_Value(Ov)),
m_OneUse(m_ICmp(Pred, m_ExtractValue<0>(m_Deferred(WOV)),
m_APInt(C2))))) &&
(WO->getBinaryOp() == Instruction::Add ||
WO->getBinaryOp() == Instruction::Sub) &&
(ICmpInst::isEquality(Pred) ||
WO->isSigned() == ICmpInst::isSigned(Pred)) &&
match(WO->getRHS(), m_APInt(C1))) {
bool Overflow;
APInt NewC = WO->getBinaryOp() == Instruction::Add
? (ICmpInst::isSigned(Pred) ? C2->ssub_ov(*C1, Overflow)
: C2->usub_ov(*C1, Overflow))
: (ICmpInst::isSigned(Pred) ? C2->sadd_ov(*C1, Overflow)
: C2->uadd_ov(*C1, Overflow));
if (!Overflow || ICmpInst::isEquality(Pred)) {
Value *NewCmp = Builder.CreateICmp(
Pred, WO->getLHS(), ConstantInt::get(WO->getLHS()->getType(), NewC));
return BinaryOperator::CreateOr(Ov, NewCmp);
}
}
// (~x) | y --> ~(x & (~y)) iff that gets rid of inversions
if (sinkNotIntoOtherHandOfLogicalOp(I))
return &I;
// Improve "get low bit mask up to and including bit X" pattern:
// (1 << X) | ((1 << X) + -1) --> -1 l>> (bitwidth(x) - 1 - X)
if (match(&I, m_c_Or(m_Add(m_Shl(m_One(), m_Value(X)), m_AllOnes()),
m_Shl(m_One(), m_Deferred(X)))) &&
match(&I, m_c_Or(m_OneUse(m_Value()), m_Value()))) {
Value *Sub = Builder.CreateSub(
ConstantInt::get(Ty, Ty->getScalarSizeInBits() - 1), X);
return BinaryOperator::CreateLShr(Constant::getAllOnesValue(Ty), Sub);
}
// An or recurrence w/loop invariant step is equivelent to (or start, step)
PHINode *PN = nullptr;
Value *Start = nullptr, *Step = nullptr;
if (matchSimpleRecurrence(&I, PN, Start, Step) && DT.dominates(Step, PN))
return replaceInstUsesWith(I, Builder.CreateOr(Start, Step));
// (A & B) | (C | D) or (C | D) | (A & B)
// Can be combined if C or D is of type (A/B & X)
if (match(&I, m_c_Or(m_OneUse(m_And(m_Value(A), m_Value(B))),
m_OneUse(m_Or(m_Value(C), m_Value(D)))))) {
// (A & B) | (C | ?) -> C | (? | (A & B))
// (A & B) | (C | ?) -> C | (? | (A & B))
// (A & B) | (C | ?) -> C | (? | (A & B))
// (A & B) | (C | ?) -> C | (? | (A & B))
// (C | ?) | (A & B) -> C | (? | (A & B))
// (C | ?) | (A & B) -> C | (? | (A & B))
// (C | ?) | (A & B) -> C | (? | (A & B))
// (C | ?) | (A & B) -> C | (? | (A & B))
if (match(D, m_OneUse(m_c_And(m_Specific(A), m_Value()))) ||
match(D, m_OneUse(m_c_And(m_Specific(B), m_Value()))))
return BinaryOperator::CreateOr(
C, Builder.CreateOr(D, Builder.CreateAnd(A, B)));
// (A & B) | (? | D) -> (? | (A & B)) | D
// (A & B) | (? | D) -> (? | (A & B)) | D
// (A & B) | (? | D) -> (? | (A & B)) | D
// (A & B) | (? | D) -> (? | (A & B)) | D
// (? | D) | (A & B) -> (? | (A & B)) | D
// (? | D) | (A & B) -> (? | (A & B)) | D
// (? | D) | (A & B) -> (? | (A & B)) | D
// (? | D) | (A & B) -> (? | (A & B)) | D
if (match(C, m_OneUse(m_c_And(m_Specific(A), m_Value()))) ||
match(C, m_OneUse(m_c_And(m_Specific(B), m_Value()))))
return BinaryOperator::CreateOr(
Builder.CreateOr(C, Builder.CreateAnd(A, B)), D);
}
if (Instruction *R = reassociateForUses(I, Builder))
return R;
if (Instruction *Canonicalized = canonicalizeLogicFirst(I, Builder))
return Canonicalized;
if (Instruction *Folded = foldLogicOfIsFPClass(I, Op0, Op1))
return Folded;
if (Instruction *Res = foldBinOpOfDisplacedShifts(I))
return Res;
// If we are setting the sign bit of a floating-point value, convert
// this to fneg(fabs), then cast back to integer.
//
// If the result isn't immediately cast back to a float, this will increase
// the number of instructions. This is still probably a better canonical form
// as it enables FP value tracking.
//
// Assumes any IEEE-represented type has the sign bit in the high bit.
//
// This is generous interpretation of noimplicitfloat, this is not a true
// floating-point operation.
Value *CastOp;
if (match(Op0, m_ElementWiseBitCast(m_Value(CastOp))) &&
match(Op1, m_SignMask()) &&
!Builder.GetInsertBlock()->getParent()->hasFnAttribute(
Attribute::NoImplicitFloat)) {
Type *EltTy = CastOp->getType()->getScalarType();
if (EltTy->isFloatingPointTy() && EltTy->isIEEE()) {
Value *FAbs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, CastOp);
Value *FNegFAbs = Builder.CreateFNeg(FAbs);
return new BitCastInst(FNegFAbs, I.getType());
}
}
// (X & C1) | C2 -> X & (C1 | C2) iff (X & C2) == C2
if (match(Op0, m_OneUse(m_And(m_Value(X), m_APInt(C1)))) &&
match(Op1, m_APInt(C2))) {
KnownBits KnownX = computeKnownBits(X, /*Depth*/ 0, &I);
if ((KnownX.One & *C2) == *C2)
return BinaryOperator::CreateAnd(X, ConstantInt::get(Ty, *C1 | *C2));
}
if (Instruction *Res = foldBitwiseLogicWithIntrinsics(I, Builder))
return Res;
if (Value *V =
simplifyAndOrWithOpReplaced(Op0, Op1, Constant::getNullValue(Ty),
/*SimplifyOnly*/ false, *this))
return BinaryOperator::CreateOr(V, Op1);
if (Value *V =
simplifyAndOrWithOpReplaced(Op1, Op0, Constant::getNullValue(Ty),
/*SimplifyOnly*/ false, *this))
return BinaryOperator::CreateOr(Op0, V);
if (cast<PossiblyDisjointInst>(I).isDisjoint())
if (Value *V = SimplifyAddWithRemainder(I))
return replaceInstUsesWith(I, V);
return nullptr;
}
/// A ^ B can be specified using other logic ops in a variety of patterns. We
/// can fold these early and efficiently by morphing an existing instruction.
static Instruction *foldXorToXor(BinaryOperator &I,
InstCombiner::BuilderTy &Builder) {
assert(I.getOpcode() == Instruction::Xor);
Value *Op0 = I.getOperand(0);
Value *Op1 = I.getOperand(1);
Value *A, *B;
// There are 4 commuted variants for each of the basic patterns.
// (A & B) ^ (A | B) -> A ^ B
// (A & B) ^ (B | A) -> A ^ B
// (A | B) ^ (A & B) -> A ^ B
// (A | B) ^ (B & A) -> A ^ B
if (match(&I, m_c_Xor(m_And(m_Value(A), m_Value(B)),
m_c_Or(m_Deferred(A), m_Deferred(B)))))
return BinaryOperator::CreateXor(A, B);
// (A | ~B) ^ (~A | B) -> A ^ B
// (~B | A) ^ (~A | B) -> A ^ B
// (~A | B) ^ (A | ~B) -> A ^ B
// (B | ~A) ^ (A | ~B) -> A ^ B
if (match(&I, m_Xor(m_c_Or(m_Value(A), m_Not(m_Value(B))),
m_c_Or(m_Not(m_Deferred(A)), m_Deferred(B)))))
return BinaryOperator::CreateXor(A, B);
// (A & ~B) ^ (~A & B) -> A ^ B
// (~B & A) ^ (~A & B) -> A ^ B
// (~A & B) ^ (A & ~B) -> A ^ B
// (B & ~A) ^ (A & ~B) -> A ^ B
if (match(&I, m_Xor(m_c_And(m_Value(A), m_Not(m_Value(B))),
m_c_And(m_Not(m_Deferred(A)), m_Deferred(B)))))
return BinaryOperator::CreateXor(A, B);
// For the remaining cases we need to get rid of one of the operands.
if (!Op0->hasOneUse() && !Op1->hasOneUse())
return nullptr;
// (A | B) ^ ~(A & B) -> ~(A ^ B)
// (A | B) ^ ~(B & A) -> ~(A ^ B)
// (A & B) ^ ~(A | B) -> ~(A ^ B)
// (A & B) ^ ~(B | A) -> ~(A ^ B)
// Complexity sorting ensures the not will be on the right side.
if ((match(Op0, m_Or(m_Value(A), m_Value(B))) &&
match(Op1, m_Not(m_c_And(m_Specific(A), m_Specific(B))))) ||
(match(Op0, m_And(m_Value(A), m_Value(B))) &&
match(Op1, m_Not(m_c_Or(m_Specific(A), m_Specific(B))))))
return BinaryOperator::CreateNot(Builder.CreateXor(A, B));
return nullptr;
}
Value *InstCombinerImpl::foldXorOfICmps(ICmpInst *LHS, ICmpInst *RHS,
BinaryOperator &I) {
assert(I.getOpcode() == Instruction::Xor && I.getOperand(0) == LHS &&
I.getOperand(1) == RHS && "Should be 'xor' with these operands");
ICmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
Value *LHS0 = LHS->getOperand(0), *LHS1 = LHS->getOperand(1);
Value *RHS0 = RHS->getOperand(0), *RHS1 = RHS->getOperand(1);
if (predicatesFoldable(PredL, PredR)) {
if (LHS0 == RHS1 && LHS1 == RHS0) {
std::swap(LHS0, LHS1);
PredL = ICmpInst::getSwappedPredicate(PredL);
}
if (LHS0 == RHS0 && LHS1 == RHS1) {
// (icmp1 A, B) ^ (icmp2 A, B) --> (icmp3 A, B)
unsigned Code = getICmpCode(PredL) ^ getICmpCode(PredR);
bool IsSigned = LHS->isSigned() || RHS->isSigned();
return getNewICmpValue(Code, IsSigned, LHS0, LHS1, Builder);
}
}
const APInt *LC, *RC;
if (match(LHS1, m_APInt(LC)) && match(RHS1, m_APInt(RC)) &&
LHS0->getType() == RHS0->getType() &&
LHS0->getType()->isIntOrIntVectorTy()) {
// Convert xor of signbit tests to signbit test of xor'd values:
// (X > -1) ^ (Y > -1) --> (X ^ Y) < 0
// (X < 0) ^ (Y < 0) --> (X ^ Y) < 0
// (X > -1) ^ (Y < 0) --> (X ^ Y) > -1
// (X < 0) ^ (Y > -1) --> (X ^ Y) > -1
bool TrueIfSignedL, TrueIfSignedR;
if ((LHS->hasOneUse() || RHS->hasOneUse()) &&
isSignBitCheck(PredL, *LC, TrueIfSignedL) &&
isSignBitCheck(PredR, *RC, TrueIfSignedR)) {
Value *XorLR = Builder.CreateXor(LHS0, RHS0);
return TrueIfSignedL == TrueIfSignedR ? Builder.CreateIsNeg(XorLR) :
Builder.CreateIsNotNeg(XorLR);
}
// Fold (icmp pred1 X, C1) ^ (icmp pred2 X, C2)
// into a single comparison using range-based reasoning.
if (LHS0 == RHS0) {
ConstantRange CR1 = ConstantRange::makeExactICmpRegion(PredL, *LC);
ConstantRange CR2 = ConstantRange::makeExactICmpRegion(PredR, *RC);
auto CRUnion = CR1.exactUnionWith(CR2);
auto CRIntersect = CR1.exactIntersectWith(CR2);
if (CRUnion && CRIntersect)
if (auto CR = CRUnion->exactIntersectWith(CRIntersect->inverse())) {
if (CR->isFullSet())
return ConstantInt::getTrue(I.getType());
if (CR->isEmptySet())
return ConstantInt::getFalse(I.getType());
CmpInst::Predicate NewPred;
APInt NewC, Offset;
CR->getEquivalentICmp(NewPred, NewC, Offset);
if ((Offset.isZero() && (LHS->hasOneUse() || RHS->hasOneUse())) ||
(LHS->hasOneUse() && RHS->hasOneUse())) {
Value *NewV = LHS0;
Type *Ty = LHS0->getType();
if (!Offset.isZero())
NewV = Builder.CreateAdd(NewV, ConstantInt::get(Ty, Offset));
return Builder.CreateICmp(NewPred, NewV,
ConstantInt::get(Ty, NewC));
}
}
}
// Fold (icmp eq/ne (X & Pow2), 0) ^ (icmp eq/ne (Y & Pow2), 0) into
// (icmp eq/ne ((X ^ Y) & Pow2), 0)
Value *X, *Y, *Pow2;
if (ICmpInst::isEquality(PredL) && ICmpInst::isEquality(PredR) &&
LC->isZero() && RC->isZero() && LHS->hasOneUse() && RHS->hasOneUse() &&
match(LHS0, m_And(m_Value(X), m_Value(Pow2))) &&
match(RHS0, m_And(m_Value(Y), m_Specific(Pow2))) &&
isKnownToBeAPowerOfTwo(Pow2, /*OrZero=*/true, /*Depth=*/0, &I)) {
Value *Xor = Builder.CreateXor(X, Y);
Value *And = Builder.CreateAnd(Xor, Pow2);
return Builder.CreateICmp(PredL == PredR ? ICmpInst::ICMP_NE
: ICmpInst::ICMP_EQ,
And, ConstantInt::getNullValue(Xor->getType()));
}
}
// Instead of trying to imitate the folds for and/or, decompose this 'xor'
// into those logic ops. That is, try to turn this into an and-of-icmps
// because we have many folds for that pattern.
//
// This is based on a truth table definition of xor:
// X ^ Y --> (X | Y) & !(X & Y)
if (Value *OrICmp = simplifyBinOp(Instruction::Or, LHS, RHS, SQ)) {
// TODO: If OrICmp is true, then the definition of xor simplifies to !(X&Y).
// TODO: If OrICmp is false, the whole thing is false (InstSimplify?).
if (Value *AndICmp = simplifyBinOp(Instruction::And, LHS, RHS, SQ)) {
// TODO: Independently handle cases where the 'and' side is a constant.
ICmpInst *X = nullptr, *Y = nullptr;
if (OrICmp == LHS && AndICmp == RHS) {
// (LHS | RHS) & !(LHS & RHS) --> LHS & !RHS --> X & !Y
X = LHS;
Y = RHS;
}
if (OrICmp == RHS && AndICmp == LHS) {
// !(LHS & RHS) & (LHS | RHS) --> !LHS & RHS --> !Y & X
X = RHS;
Y = LHS;
}
if (X && Y && (Y->hasOneUse() || canFreelyInvertAllUsersOf(Y, &I))) {
// Invert the predicate of 'Y', thus inverting its output.
Y->setPredicate(Y->getInversePredicate());
// So, are there other uses of Y?
if (!Y->hasOneUse()) {
// We need to adapt other uses of Y though. Get a value that matches
// the original value of Y before inversion. While this increases
// immediate instruction count, we have just ensured that all the
// users are freely-invertible, so that 'not' *will* get folded away.
BuilderTy::InsertPointGuard Guard(Builder);
// Set insertion point to right after the Y.
Builder.SetInsertPoint(Y->getParent(), ++(Y->getIterator()));
Value *NotY = Builder.CreateNot(Y, Y->getName() + ".not");
// Replace all uses of Y (excluding the one in NotY!) with NotY.
Worklist.pushUsersToWorkList(*Y);
Y->replaceUsesWithIf(NotY,
[NotY](Use &U) { return U.getUser() != NotY; });
}
// All done.
return Builder.CreateAnd(LHS, RHS);
}
}
}
return nullptr;
}
/// If we have a masked merge, in the canonical form of:
/// (assuming that A only has one use.)
/// | A | |B|
/// ((x ^ y) & M) ^ y
/// | D |
/// * If M is inverted:
/// | D |
/// ((x ^ y) & ~M) ^ y
/// We can canonicalize by swapping the final xor operand
/// to eliminate the 'not' of the mask.
/// ((x ^ y) & M) ^ x
/// * If M is a constant, and D has one use, we transform to 'and' / 'or' ops
/// because that shortens the dependency chain and improves analysis:
/// (x & M) | (y & ~M)
static Instruction *visitMaskedMerge(BinaryOperator &I,
InstCombiner::BuilderTy &Builder) {
Value *B, *X, *D;
Value *M;
if (!match(&I, m_c_Xor(m_Value(B),
m_OneUse(m_c_And(
m_CombineAnd(m_c_Xor(m_Deferred(B), m_Value(X)),
m_Value(D)),
m_Value(M))))))
return nullptr;
Value *NotM;
if (match(M, m_Not(m_Value(NotM)))) {
// De-invert the mask and swap the value in B part.
Value *NewA = Builder.CreateAnd(D, NotM);
return BinaryOperator::CreateXor(NewA, X);
}
Constant *C;
if (D->hasOneUse() && match(M, m_Constant(C))) {
// Propagating undef is unsafe. Clamp undef elements to -1.
Type *EltTy = C->getType()->getScalarType();
C = Constant::replaceUndefsWith(C, ConstantInt::getAllOnesValue(EltTy));
// Unfold.
Value *LHS = Builder.CreateAnd(X, C);
Value *NotC = Builder.CreateNot(C);
Value *RHS = Builder.CreateAnd(B, NotC);
return BinaryOperator::CreateOr(LHS, RHS);
}
return nullptr;
}
static Instruction *foldNotXor(BinaryOperator &I,
InstCombiner::BuilderTy &Builder) {
Value *X, *Y;
// FIXME: one-use check is not needed in general, but currently we are unable
// to fold 'not' into 'icmp', if that 'icmp' has multiple uses. (D35182)
if (!match(&I, m_Not(m_OneUse(m_Xor(m_Value(X), m_Value(Y))))))
return nullptr;
auto hasCommonOperand = [](Value *A, Value *B, Value *C, Value *D) {
return A == C || A == D || B == C || B == D;
};
Value *A, *B, *C, *D;
// Canonicalize ~((A & B) ^ (A | ?)) -> (A & B) | ~(A | ?)
// 4 commuted variants
if (match(X, m_And(m_Value(A), m_Value(B))) &&
match(Y, m_Or(m_Value(C), m_Value(D))) && hasCommonOperand(A, B, C, D)) {
Value *NotY = Builder.CreateNot(Y);
return BinaryOperator::CreateOr(X, NotY);
};
// Canonicalize ~((A | ?) ^ (A & B)) -> (A & B) | ~(A | ?)
// 4 commuted variants
if (match(Y, m_And(m_Value(A), m_Value(B))) &&
match(X, m_Or(m_Value(C), m_Value(D))) && hasCommonOperand(A, B, C, D)) {
Value *NotX = Builder.CreateNot(X);
return BinaryOperator::CreateOr(Y, NotX);
};
return nullptr;
}
/// Canonicalize a shifty way to code absolute value to the more common pattern
/// that uses negation and select.
static Instruction *canonicalizeAbs(BinaryOperator &Xor,
InstCombiner::BuilderTy &Builder) {
assert(Xor.getOpcode() == Instruction::Xor && "Expected an xor instruction.");
// There are 4 potential commuted variants. Move the 'ashr' candidate to Op1.
// We're relying on the fact that we only do this transform when the shift has
// exactly 2 uses and the add has exactly 1 use (otherwise, we might increase
// instructions).
Value *Op0 = Xor.getOperand(0), *Op1 = Xor.getOperand(1);
if (Op0->hasNUses(2))
std::swap(Op0, Op1);
Type *Ty = Xor.getType();
Value *A;
const APInt *ShAmt;
if (match(Op1, m_AShr(m_Value(A), m_APInt(ShAmt))) &&
Op1->hasNUses(2) && *ShAmt == Ty->getScalarSizeInBits() - 1 &&
match(Op0, m_OneUse(m_c_Add(m_Specific(A), m_Specific(Op1))))) {
// Op1 = ashr i32 A, 31 ; smear the sign bit
// xor (add A, Op1), Op1 ; add -1 and flip bits if negative
// --> (A < 0) ? -A : A
Value *IsNeg = Builder.CreateIsNeg(A);
// Copy the nsw flags from the add to the negate.
auto *Add = cast<BinaryOperator>(Op0);
Value *NegA = Add->hasNoUnsignedWrap()
? Constant::getNullValue(A->getType())
: Builder.CreateNeg(A, "", Add->hasNoSignedWrap());
return SelectInst::Create(IsNeg, NegA, A);
}
return nullptr;
}
static bool canFreelyInvert(InstCombiner &IC, Value *Op,
Instruction *IgnoredUser) {
auto *I = dyn_cast<Instruction>(Op);
return I && IC.isFreeToInvert(I, /*WillInvertAllUses=*/true) &&
IC.canFreelyInvertAllUsersOf(I, IgnoredUser);
}
static Value *freelyInvert(InstCombinerImpl &IC, Value *Op,
Instruction *IgnoredUser) {
auto *I = cast<Instruction>(Op);
IC.Builder.SetInsertPoint(*I->getInsertionPointAfterDef());
Value *NotOp = IC.Builder.CreateNot(Op, Op->getName() + ".not");
Op->replaceUsesWithIf(NotOp,
[NotOp](Use &U) { return U.getUser() != NotOp; });
IC.freelyInvertAllUsersOf(NotOp, IgnoredUser);
return NotOp;
}
// Transform
// z = ~(x &/| y)
// into:
// z = ((~x) |/& (~y))
// iff both x and y are free to invert and all uses of z can be freely updated.
bool InstCombinerImpl::sinkNotIntoLogicalOp(Instruction &I) {
Value *Op0, *Op1;
if (!match(&I, m_LogicalOp(m_Value(Op0), m_Value(Op1))))
return false;
// If this logic op has not been simplified yet, just bail out and let that
// happen first. Otherwise, the code below may wrongly invert.
if (Op0 == Op1)
return false;
Instruction::BinaryOps NewOpc =
match(&I, m_LogicalAnd()) ? Instruction::Or : Instruction::And;
bool IsBinaryOp = isa<BinaryOperator>(I);
// Can our users be adapted?
if (!InstCombiner::canFreelyInvertAllUsersOf(&I, /*IgnoredUser=*/nullptr))
return false;
// And can the operands be adapted?
if (!canFreelyInvert(*this, Op0, &I) || !canFreelyInvert(*this, Op1, &I))
return false;
Op0 = freelyInvert(*this, Op0, &I);
Op1 = freelyInvert(*this, Op1, &I);
Builder.SetInsertPoint(*I.getInsertionPointAfterDef());
Value *NewLogicOp;
if (IsBinaryOp)
NewLogicOp = Builder.CreateBinOp(NewOpc, Op0, Op1, I.getName() + ".not");
else
NewLogicOp =
Builder.CreateLogicalOp(NewOpc, Op0, Op1, I.getName() + ".not");
replaceInstUsesWith(I, NewLogicOp);
// We can not just create an outer `not`, it will most likely be immediately
// folded back, reconstructing our initial pattern, and causing an
// infinite combine loop, so immediately manually fold it away.
freelyInvertAllUsersOf(NewLogicOp);
return true;
}
// Transform
// z = (~x) &/| y
// into:
// z = ~(x |/& (~y))
// iff y is free to invert and all uses of z can be freely updated.
bool InstCombinerImpl::sinkNotIntoOtherHandOfLogicalOp(Instruction &I) {
Value *Op0, *Op1;
if (!match(&I, m_LogicalOp(m_Value(Op0), m_Value(Op1))))
return false;
Instruction::BinaryOps NewOpc =
match(&I, m_LogicalAnd()) ? Instruction::Or : Instruction::And;
bool IsBinaryOp = isa<BinaryOperator>(I);
Value *NotOp0 = nullptr;
Value *NotOp1 = nullptr;
Value **OpToInvert = nullptr;
if (match(Op0, m_Not(m_Value(NotOp0))) && canFreelyInvert(*this, Op1, &I)) {
Op0 = NotOp0;
OpToInvert = &Op1;
} else if (match(Op1, m_Not(m_Value(NotOp1))) &&
canFreelyInvert(*this, Op0, &I)) {
Op1 = NotOp1;
OpToInvert = &Op0;
} else
return false;
// And can our users be adapted?
if (!InstCombiner::canFreelyInvertAllUsersOf(&I, /*IgnoredUser=*/nullptr))
return false;
*OpToInvert = freelyInvert(*this, *OpToInvert, &I);
Builder.SetInsertPoint(*I.getInsertionPointAfterDef());
Value *NewBinOp;
if (IsBinaryOp)
NewBinOp = Builder.CreateBinOp(NewOpc, Op0, Op1, I.getName() + ".not");
else
NewBinOp = Builder.CreateLogicalOp(NewOpc, Op0, Op1, I.getName() + ".not");
replaceInstUsesWith(I, NewBinOp);
// We can not just create an outer `not`, it will most likely be immediately
// folded back, reconstructing our initial pattern, and causing an
// infinite combine loop, so immediately manually fold it away.
freelyInvertAllUsersOf(NewBinOp);
return true;
}
Instruction *InstCombinerImpl::foldNot(BinaryOperator &I) {
Value *NotOp;
if (!match(&I, m_Not(m_Value(NotOp))))
return nullptr;
// Apply DeMorgan's Law for 'nand' / 'nor' logic with an inverted operand.
// We must eliminate the and/or (one-use) for these transforms to not increase
// the instruction count.
//
// ~(~X & Y) --> (X | ~Y)
// ~(Y & ~X) --> (X | ~Y)
//
// Note: The logical matches do not check for the commuted patterns because
// those are handled via SimplifySelectsFeedingBinaryOp().
Type *Ty = I.getType();
Value *X, *Y;
if (match(NotOp, m_OneUse(m_c_And(m_Not(m_Value(X)), m_Value(Y))))) {
Value *NotY = Builder.CreateNot(Y, Y->getName() + ".not");
return BinaryOperator::CreateOr(X, NotY);
}
if (match(NotOp, m_OneUse(m_LogicalAnd(m_Not(m_Value(X)), m_Value(Y))))) {
Value *NotY = Builder.CreateNot(Y, Y->getName() + ".not");
return SelectInst::Create(X, ConstantInt::getTrue(Ty), NotY);
}
// ~(~X | Y) --> (X & ~Y)
// ~(Y | ~X) --> (X & ~Y)
if (match(NotOp, m_OneUse(m_c_Or(m_Not(m_Value(X)), m_Value(Y))))) {
Value *NotY = Builder.CreateNot(Y, Y->getName() + ".not");
return BinaryOperator::CreateAnd(X, NotY);
}
if (match(NotOp, m_OneUse(m_LogicalOr(m_Not(m_Value(X)), m_Value(Y))))) {
Value *NotY = Builder.CreateNot(Y, Y->getName() + ".not");
return SelectInst::Create(X, NotY, ConstantInt::getFalse(Ty));
}
// Is this a 'not' (~) fed by a binary operator?
BinaryOperator *NotVal;
if (match(NotOp, m_BinOp(NotVal))) {
// ~((-X) | Y) --> (X - 1) & (~Y)
if (match(NotVal,
m_OneUse(m_c_Or(m_OneUse(m_Neg(m_Value(X))), m_Value(Y))))) {
Value *DecX = Builder.CreateAdd(X, ConstantInt::getAllOnesValue(Ty));
Value *NotY = Builder.CreateNot(Y);
return BinaryOperator::CreateAnd(DecX, NotY);
}
// ~(~X >>s Y) --> (X >>s Y)
if (match(NotVal, m_AShr(m_Not(m_Value(X)), m_Value(Y))))
return BinaryOperator::CreateAShr(X, Y);
// Treat lshr with non-negative operand as ashr.
// ~(~X >>u Y) --> (X >>s Y) iff X is known negative
if (match(NotVal, m_LShr(m_Not(m_Value(X)), m_Value(Y))) &&
isKnownNegative(X, SQ.getWithInstruction(NotVal)))
return BinaryOperator::CreateAShr(X, Y);
// Bit-hack form of a signbit test for iN type:
// ~(X >>s (N - 1)) --> sext i1 (X > -1) to iN
unsigned FullShift = Ty->getScalarSizeInBits() - 1;
if (match(NotVal, m_OneUse(m_AShr(m_Value(X), m_SpecificInt(FullShift))))) {
Value *IsNotNeg = Builder.CreateIsNotNeg(X, "isnotneg");
return new SExtInst(IsNotNeg, Ty);
}
// If we are inverting a right-shifted constant, we may be able to eliminate
// the 'not' by inverting the constant and using the opposite shift type.
// Canonicalization rules ensure that only a negative constant uses 'ashr',
// but we must check that in case that transform has not fired yet.
// ~(C >>s Y) --> ~C >>u Y (when inverting the replicated sign bits)
Constant *C;
if (match(NotVal, m_AShr(m_Constant(C), m_Value(Y))) &&
match(C, m_Negative()))
return BinaryOperator::CreateLShr(ConstantExpr::getNot(C), Y);
// ~(C >>u Y) --> ~C >>s Y (when inverting the replicated sign bits)
if (match(NotVal, m_LShr(m_Constant(C), m_Value(Y))) &&
match(C, m_NonNegative()))
return BinaryOperator::CreateAShr(ConstantExpr::getNot(C), Y);
// ~(X + C) --> ~C - X
if (match(NotVal, m_Add(m_Value(X), m_ImmConstant(C))))
return BinaryOperator::CreateSub(ConstantExpr::getNot(C), X);
// ~(X - Y) --> ~X + Y
// FIXME: is it really beneficial to sink the `not` here?
if (match(NotVal, m_Sub(m_Value(X), m_Value(Y))))
if (isa<Constant>(X) || NotVal->hasOneUse())
return BinaryOperator::CreateAdd(Builder.CreateNot(X), Y);
// ~(~X + Y) --> X - Y
if (match(NotVal, m_c_Add(m_Not(m_Value(X)), m_Value(Y))))
return BinaryOperator::CreateWithCopiedFlags(Instruction::Sub, X, Y,
NotVal);
}
// not (cmp A, B) = !cmp A, B
CmpPredicate Pred;
if (match(NotOp, m_Cmp(Pred, m_Value(), m_Value())) &&
(NotOp->hasOneUse() ||
InstCombiner::canFreelyInvertAllUsersOf(cast<Instruction>(NotOp),
/*IgnoredUser=*/nullptr))) {
cast<CmpInst>(NotOp)->setPredicate(CmpInst::getInversePredicate(Pred));
freelyInvertAllUsersOf(NotOp);
return &I;
}
// Move a 'not' ahead of casts of a bool to enable logic reduction:
// not (bitcast (sext i1 X)) --> bitcast (sext (not i1 X))
if (match(NotOp, m_OneUse(m_BitCast(m_OneUse(m_SExt(m_Value(X)))))) && X->getType()->isIntOrIntVectorTy(1)) {
Type *SextTy = cast<BitCastOperator>(NotOp)->getSrcTy();
Value *NotX = Builder.CreateNot(X);
Value *Sext = Builder.CreateSExt(NotX, SextTy);
return new BitCastInst(Sext, Ty);
}
if (auto *NotOpI = dyn_cast<Instruction>(NotOp))
if (sinkNotIntoLogicalOp(*NotOpI))
return &I;
// Eliminate a bitwise 'not' op of 'not' min/max by inverting the min/max:
// ~min(~X, ~Y) --> max(X, Y)
// ~max(~X, Y) --> min(X, ~Y)
auto *II = dyn_cast<IntrinsicInst>(NotOp);
if (II && II->hasOneUse()) {
if (match(NotOp, m_c_MaxOrMin(m_Not(m_Value(X)), m_Value(Y)))) {
Intrinsic::ID InvID = getInverseMinMaxIntrinsic(II->getIntrinsicID());
Value *NotY = Builder.CreateNot(Y);
Value *InvMaxMin = Builder.CreateBinaryIntrinsic(InvID, X, NotY);
return replaceInstUsesWith(I, InvMaxMin);
}
if (II->getIntrinsicID() == Intrinsic::is_fpclass) {
ConstantInt *ClassMask = cast<ConstantInt>(II->getArgOperand(1));
II->setArgOperand(
1, ConstantInt::get(ClassMask->getType(),
~ClassMask->getZExtValue() & fcAllFlags));
return replaceInstUsesWith(I, II);
}
}
if (NotOp->hasOneUse()) {
// Pull 'not' into operands of select if both operands are one-use compares
// or one is one-use compare and the other one is a constant.
// Inverting the predicates eliminates the 'not' operation.
// Example:
// not (select ?, (cmp TPred, ?, ?), (cmp FPred, ?, ?) -->
// select ?, (cmp InvTPred, ?, ?), (cmp InvFPred, ?, ?)
// not (select ?, (cmp TPred, ?, ?), true -->
// select ?, (cmp InvTPred, ?, ?), false
if (auto *Sel = dyn_cast<SelectInst>(NotOp)) {
Value *TV = Sel->getTrueValue();
Value *FV = Sel->getFalseValue();
auto *CmpT = dyn_cast<CmpInst>(TV);
auto *CmpF = dyn_cast<CmpInst>(FV);
bool InvertibleT = (CmpT && CmpT->hasOneUse()) || isa<Constant>(TV);
bool InvertibleF = (CmpF && CmpF->hasOneUse()) || isa<Constant>(FV);
if (InvertibleT && InvertibleF) {
if (CmpT)
CmpT->setPredicate(CmpT->getInversePredicate());
else
Sel->setTrueValue(ConstantExpr::getNot(cast<Constant>(TV)));
if (CmpF)
CmpF->setPredicate(CmpF->getInversePredicate());
else
Sel->setFalseValue(ConstantExpr::getNot(cast<Constant>(FV)));
return replaceInstUsesWith(I, Sel);
}
}
}
if (Instruction *NewXor = foldNotXor(I, Builder))
return NewXor;
// TODO: Could handle multi-use better by checking if all uses of NotOp (other
// than I) can be inverted.
if (Value *R = getFreelyInverted(NotOp, NotOp->hasOneUse(), &Builder))
return replaceInstUsesWith(I, R);
return nullptr;
}
// FIXME: We use commutative matchers (m_c_*) for some, but not all, matches
// here. We should standardize that construct where it is needed or choose some
// other way to ensure that commutated variants of patterns are not missed.
Instruction *InstCombinerImpl::visitXor(BinaryOperator &I) {
if (Value *V = simplifyXorInst(I.getOperand(0), I.getOperand(1),
SQ.getWithInstruction(&I)))
return replaceInstUsesWith(I, V);
if (SimplifyAssociativeOrCommutative(I))
return &I;
if (Instruction *X = foldVectorBinop(I))
return X;
if (Instruction *Phi = foldBinopWithPhiOperands(I))
return Phi;
if (Instruction *NewXor = foldXorToXor(I, Builder))
return NewXor;
// (A&B)^(A&C) -> A&(B^C) etc
if (Value *V = foldUsingDistributiveLaws(I))
return replaceInstUsesWith(I, V);
// See if we can simplify any instructions used by the instruction whose sole
// purpose is to compute bits we don't care about.
if (SimplifyDemandedInstructionBits(I))
return &I;
if (Instruction *R = foldNot(I))
return R;
if (Instruction *R = foldBinOpShiftWithShift(I))
return R;
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
Value *X, *Y, *M;
// (X | Y) ^ M -> (X ^ M) ^ Y
// (X | Y) ^ M -> (Y ^ M) ^ X
if (match(&I, m_c_Xor(m_OneUse(m_DisjointOr(m_Value(X), m_Value(Y))),
m_Value(M)))) {
if (Value *XorAC = simplifyXorInst(X, M, SQ.getWithInstruction(&I)))
return BinaryOperator::CreateXor(XorAC, Y);
if (Value *XorBC = simplifyXorInst(Y, M, SQ.getWithInstruction(&I)))
return BinaryOperator::CreateXor(XorBC, X);
}
// Fold (X & M) ^ (Y & ~M) -> (X & M) | (Y & ~M)
// This it a special case in haveNoCommonBitsSet, but the computeKnownBits
// calls in there are unnecessary as SimplifyDemandedInstructionBits should
// have already taken care of those cases.
if (match(&I, m_c_Xor(m_c_And(m_Not(m_Value(M)), m_Value()),
m_c_And(m_Deferred(M), m_Value())))) {
if (isGuaranteedNotToBeUndef(M))
return BinaryOperator::CreateDisjointOr(Op0, Op1);
else
return BinaryOperator::CreateOr(Op0, Op1);
}
if (Instruction *Xor = visitMaskedMerge(I, Builder))
return Xor;
Constant *C1;
if (match(Op1, m_Constant(C1))) {
Constant *C2;
if (match(Op0, m_OneUse(m_Or(m_Value(X), m_ImmConstant(C2)))) &&
match(C1, m_ImmConstant())) {
// (X | C2) ^ C1 --> (X & ~C2) ^ (C1^C2)
C2 = Constant::replaceUndefsWith(
C2, Constant::getAllOnesValue(C2->getType()->getScalarType()));
Value *And = Builder.CreateAnd(
X, Constant::mergeUndefsWith(ConstantExpr::getNot(C2), C1));
return BinaryOperator::CreateXor(
And, Constant::mergeUndefsWith(ConstantExpr::getXor(C1, C2), C1));
}
// Use DeMorgan and reassociation to eliminate a 'not' op.
if (match(Op0, m_OneUse(m_Or(m_Not(m_Value(X)), m_Constant(C2))))) {
// (~X | C2) ^ C1 --> ((X & ~C2) ^ -1) ^ C1 --> (X & ~C2) ^ ~C1
Value *And = Builder.CreateAnd(X, ConstantExpr::getNot(C2));
return BinaryOperator::CreateXor(And, ConstantExpr::getNot(C1));
}
if (match(Op0, m_OneUse(m_And(m_Not(m_Value(X)), m_Constant(C2))))) {
// (~X & C2) ^ C1 --> ((X | ~C2) ^ -1) ^ C1 --> (X | ~C2) ^ ~C1
Value *Or = Builder.CreateOr(X, ConstantExpr::getNot(C2));
return BinaryOperator::CreateXor(Or, ConstantExpr::getNot(C1));
}
// Convert xor ([trunc] (ashr X, BW-1)), C =>
// select(X >s -1, C, ~C)
// The ashr creates "AllZeroOrAllOne's", which then optionally inverses the
// constant depending on whether this input is less than 0.
const APInt *CA;
if (match(Op0, m_OneUse(m_TruncOrSelf(
m_AShr(m_Value(X), m_APIntAllowPoison(CA))))) &&
*CA == X->getType()->getScalarSizeInBits() - 1 &&
!match(C1, m_AllOnes())) {
assert(!C1->isZeroValue() && "Unexpected xor with 0");
Value *IsNotNeg = Builder.CreateIsNotNeg(X);
return SelectInst::Create(IsNotNeg, Op1, Builder.CreateNot(Op1));
}
}
Type *Ty = I.getType();
{
const APInt *RHSC;
if (match(Op1, m_APInt(RHSC))) {
Value *X;
const APInt *C;
// (C - X) ^ signmaskC --> (C + signmaskC) - X
if (RHSC->isSignMask() && match(Op0, m_Sub(m_APInt(C), m_Value(X))))
return BinaryOperator::CreateSub(ConstantInt::get(Ty, *C + *RHSC), X);
// (X + C) ^ signmaskC --> X + (C + signmaskC)
if (RHSC->isSignMask() && match(Op0, m_Add(m_Value(X), m_APInt(C))))
return BinaryOperator::CreateAdd(X, ConstantInt::get(Ty, *C + *RHSC));
// (X | C) ^ RHSC --> X ^ (C ^ RHSC) iff X & C == 0
if (match(Op0, m_Or(m_Value(X), m_APInt(C))) &&
MaskedValueIsZero(X, *C, 0, &I))
return BinaryOperator::CreateXor(X, ConstantInt::get(Ty, *C ^ *RHSC));
// When X is a power-of-two or zero and zero input is poison:
// ctlz(i32 X) ^ 31 --> cttz(X)
// cttz(i32 X) ^ 31 --> ctlz(X)
auto *II = dyn_cast<IntrinsicInst>(Op0);
if (II && II->hasOneUse() && *RHSC == Ty->getScalarSizeInBits() - 1) {
Intrinsic::ID IID = II->getIntrinsicID();
if ((IID == Intrinsic::ctlz || IID == Intrinsic::cttz) &&
match(II->getArgOperand(1), m_One()) &&
isKnownToBeAPowerOfTwo(II->getArgOperand(0), /*OrZero */ true)) {
IID = (IID == Intrinsic::ctlz) ? Intrinsic::cttz : Intrinsic::ctlz;
Function *F =
Intrinsic::getOrInsertDeclaration(II->getModule(), IID, Ty);
return CallInst::Create(F, {II->getArgOperand(0), Builder.getTrue()});
}
}
// If RHSC is inverting the remaining bits of shifted X,
// canonicalize to a 'not' before the shift to help SCEV and codegen:
// (X << C) ^ RHSC --> ~X << C
if (match(Op0, m_OneUse(m_Shl(m_Value(X), m_APInt(C)))) &&
*RHSC == APInt::getAllOnes(Ty->getScalarSizeInBits()).shl(*C)) {
Value *NotX = Builder.CreateNot(X);
return BinaryOperator::CreateShl(NotX, ConstantInt::get(Ty, *C));
}
// (X >>u C) ^ RHSC --> ~X >>u C
if (match(Op0, m_OneUse(m_LShr(m_Value(X), m_APInt(C)))) &&
*RHSC == APInt::getAllOnes(Ty->getScalarSizeInBits()).lshr(*C)) {
Value *NotX = Builder.CreateNot(X);
return BinaryOperator::CreateLShr(NotX, ConstantInt::get(Ty, *C));
}
// TODO: We could handle 'ashr' here as well. That would be matching
// a 'not' op and moving it before the shift. Doing that requires
// preventing the inverse fold in canShiftBinOpWithConstantRHS().
}
// If we are XORing the sign bit of a floating-point value, convert
// this to fneg, then cast back to integer.
//
// This is generous interpretation of noimplicitfloat, this is not a true
// floating-point operation.
//
// Assumes any IEEE-represented type has the sign bit in the high bit.
// TODO: Unify with APInt matcher. This version allows undef unlike m_APInt
Value *CastOp;
if (match(Op0, m_ElementWiseBitCast(m_Value(CastOp))) &&
match(Op1, m_SignMask()) &&
!Builder.GetInsertBlock()->getParent()->hasFnAttribute(
Attribute::NoImplicitFloat)) {
Type *EltTy = CastOp->getType()->getScalarType();
if (EltTy->isFloatingPointTy() && EltTy->isIEEE()) {
Value *FNeg = Builder.CreateFNeg(CastOp);
return new BitCastInst(FNeg, I.getType());
}
}
}
// FIXME: This should not be limited to scalar (pull into APInt match above).
{
Value *X;
ConstantInt *C1, *C2, *C3;
// ((X^C1) >> C2) ^ C3 -> (X>>C2) ^ ((C1>>C2)^C3)
if (match(Op1, m_ConstantInt(C3)) &&
match(Op0, m_LShr(m_Xor(m_Value(X), m_ConstantInt(C1)),
m_ConstantInt(C2))) &&
Op0->hasOneUse()) {
// fold (C1 >> C2) ^ C3
APInt FoldConst = C1->getValue().lshr(C2->getValue());
FoldConst ^= C3->getValue();
// Prepare the two operands.
auto *Opnd0 = Builder.CreateLShr(X, C2);
Opnd0->takeName(Op0);
return BinaryOperator::CreateXor(Opnd0, ConstantInt::get(Ty, FoldConst));
}
}
if (Instruction *FoldedLogic = foldBinOpIntoSelectOrPhi(I))
return FoldedLogic;
// Y ^ (X | Y) --> X & ~Y
// Y ^ (Y | X) --> X & ~Y
if (match(Op1, m_OneUse(m_c_Or(m_Value(X), m_Specific(Op0)))))
return BinaryOperator::CreateAnd(X, Builder.CreateNot(Op0));
// (X | Y) ^ Y --> X & ~Y
// (Y | X) ^ Y --> X & ~Y
if (match(Op0, m_OneUse(m_c_Or(m_Value(X), m_Specific(Op1)))))
return BinaryOperator::CreateAnd(X, Builder.CreateNot(Op1));
// Y ^ (X & Y) --> ~X & Y
// Y ^ (Y & X) --> ~X & Y
if (match(Op1, m_OneUse(m_c_And(m_Value(X), m_Specific(Op0)))))
return BinaryOperator::CreateAnd(Op0, Builder.CreateNot(X));
// (X & Y) ^ Y --> ~X & Y
// (Y & X) ^ Y --> ~X & Y
// Canonical form is (X & C) ^ C; don't touch that.
// TODO: A 'not' op is better for analysis and codegen, but demanded bits must
// be fixed to prefer that (otherwise we get infinite looping).
if (!match(Op1, m_Constant()) &&
match(Op0, m_OneUse(m_c_And(m_Value(X), m_Specific(Op1)))))
return BinaryOperator::CreateAnd(Op1, Builder.CreateNot(X));
Value *A, *B, *C;
// (A ^ B) ^ (A | C) --> (~A & C) ^ B -- There are 4 commuted variants.
if (match(&I, m_c_Xor(m_OneUse(m_Xor(m_Value(A), m_Value(B))),
m_OneUse(m_c_Or(m_Deferred(A), m_Value(C))))))
return BinaryOperator::CreateXor(
Builder.CreateAnd(Builder.CreateNot(A), C), B);
// (A ^ B) ^ (B | C) --> (~B & C) ^ A -- There are 4 commuted variants.
if (match(&I, m_c_Xor(m_OneUse(m_Xor(m_Value(A), m_Value(B))),
m_OneUse(m_c_Or(m_Deferred(B), m_Value(C))))))
return BinaryOperator::CreateXor(
Builder.CreateAnd(Builder.CreateNot(B), C), A);
// (A & B) ^ (A ^ B) -> (A | B)
if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
match(Op1, m_c_Xor(m_Specific(A), m_Specific(B))))
return BinaryOperator::CreateOr(A, B);
// (A ^ B) ^ (A & B) -> (A | B)
if (match(Op0, m_Xor(m_Value(A), m_Value(B))) &&
match(Op1, m_c_And(m_Specific(A), m_Specific(B))))
return BinaryOperator::CreateOr(A, B);
// (A & ~B) ^ ~A -> ~(A & B)
// (~B & A) ^ ~A -> ~(A & B)
if (match(Op0, m_c_And(m_Value(A), m_Not(m_Value(B)))) &&
match(Op1, m_Not(m_Specific(A))))
return BinaryOperator::CreateNot(Builder.CreateAnd(A, B));
// (~A & B) ^ A --> A | B -- There are 4 commuted variants.
if (match(&I, m_c_Xor(m_c_And(m_Not(m_Value(A)), m_Value(B)), m_Deferred(A))))
return BinaryOperator::CreateOr(A, B);
// (~A | B) ^ A --> ~(A & B)
if (match(Op0, m_OneUse(m_c_Or(m_Not(m_Specific(Op1)), m_Value(B)))))
return BinaryOperator::CreateNot(Builder.CreateAnd(Op1, B));
// A ^ (~A | B) --> ~(A & B)
if (match(Op1, m_OneUse(m_c_Or(m_Not(m_Specific(Op0)), m_Value(B)))))
return BinaryOperator::CreateNot(Builder.CreateAnd(Op0, B));
// (A | B) ^ (A | C) --> (B ^ C) & ~A -- There are 4 commuted variants.
// TODO: Loosen one-use restriction if common operand is a constant.
Value *D;
if (match(Op0, m_OneUse(m_Or(m_Value(A), m_Value(B)))) &&
match(Op1, m_OneUse(m_Or(m_Value(C), m_Value(D))))) {
if (B == C || B == D)
std::swap(A, B);
if (A == C)
std::swap(C, D);
if (A == D) {
Value *NotA = Builder.CreateNot(A);
return BinaryOperator::CreateAnd(Builder.CreateXor(B, C), NotA);
}
}
// (A & B) ^ (A | C) --> A ? ~B : C -- There are 4 commuted variants.
if (I.getType()->isIntOrIntVectorTy(1) &&
match(&I, m_c_Xor(m_OneUse(m_LogicalAnd(m_Value(A), m_Value(B))),
m_OneUse(m_LogicalOr(m_Value(C), m_Value(D)))))) {
bool NeedFreeze = isa<SelectInst>(Op0) && isa<SelectInst>(Op1) && B == D;
if (B == C || B == D)
std::swap(A, B);
if (A == C)
std::swap(C, D);
if (A == D) {
if (NeedFreeze)
A = Builder.CreateFreeze(A);
Value *NotB = Builder.CreateNot(B);
return SelectInst::Create(A, NotB, C);
}
}
if (auto *LHS = dyn_cast<ICmpInst>(I.getOperand(0)))
if (auto *RHS = dyn_cast<ICmpInst>(I.getOperand(1)))
if (Value *V = foldXorOfICmps(LHS, RHS, I))
return replaceInstUsesWith(I, V);
if (Instruction *CastedXor = foldCastedBitwiseLogic(I))
return CastedXor;
if (Instruction *Abs = canonicalizeAbs(I, Builder))
return Abs;
// Otherwise, if all else failed, try to hoist the xor-by-constant:
// (X ^ C) ^ Y --> (X ^ Y) ^ C
// Just like we do in other places, we completely avoid the fold
// for constantexprs, at least to avoid endless combine loop.
if (match(&I, m_c_Xor(m_OneUse(m_Xor(m_CombineAnd(m_Value(X),
m_Unless(m_ConstantExpr())),
m_ImmConstant(C1))),
m_Value(Y))))
return BinaryOperator::CreateXor(Builder.CreateXor(X, Y), C1);
if (Instruction *R = reassociateForUses(I, Builder))
return R;
if (Instruction *Canonicalized = canonicalizeLogicFirst(I, Builder))
return Canonicalized;
if (Instruction *Folded = foldLogicOfIsFPClass(I, Op0, Op1))
return Folded;
if (Instruction *Folded = canonicalizeConditionalNegationViaMathToSelect(I))
return Folded;
if (Instruction *Res = foldBinOpOfDisplacedShifts(I))
return Res;
if (Instruction *Res = foldBitwiseLogicWithIntrinsics(I, Builder))
return Res;
return nullptr;
}