forked from OSchip/llvm-project
2931 lines
114 KiB
C++
2931 lines
114 KiB
C++
//===- InstCombineAndOrXor.cpp --------------------------------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements the visitAnd, visitOr, and visitXor functions.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "InstCombineInternal.h"
|
|
#include "llvm/Analysis/CmpInstAnalysis.h"
|
|
#include "llvm/Analysis/InstructionSimplify.h"
|
|
#include "llvm/Transforms/Utils/Local.h"
|
|
#include "llvm/IR/ConstantRange.h"
|
|
#include "llvm/IR/Intrinsics.h"
|
|
#include "llvm/IR/PatternMatch.h"
|
|
using namespace llvm;
|
|
using namespace PatternMatch;
|
|
|
|
#define DEBUG_TYPE "instcombine"
|
|
|
|
/// Similar to getICmpCode but for FCmpInst. This encodes a fcmp predicate into
|
|
/// a four bit mask.
|
|
static unsigned getFCmpCode(FCmpInst::Predicate CC) {
|
|
assert(FCmpInst::FCMP_FALSE <= CC && CC <= FCmpInst::FCMP_TRUE &&
|
|
"Unexpected FCmp predicate!");
|
|
// Take advantage of the bit pattern of FCmpInst::Predicate here.
|
|
// U L G E
|
|
static_assert(FCmpInst::FCMP_FALSE == 0, ""); // 0 0 0 0
|
|
static_assert(FCmpInst::FCMP_OEQ == 1, ""); // 0 0 0 1
|
|
static_assert(FCmpInst::FCMP_OGT == 2, ""); // 0 0 1 0
|
|
static_assert(FCmpInst::FCMP_OGE == 3, ""); // 0 0 1 1
|
|
static_assert(FCmpInst::FCMP_OLT == 4, ""); // 0 1 0 0
|
|
static_assert(FCmpInst::FCMP_OLE == 5, ""); // 0 1 0 1
|
|
static_assert(FCmpInst::FCMP_ONE == 6, ""); // 0 1 1 0
|
|
static_assert(FCmpInst::FCMP_ORD == 7, ""); // 0 1 1 1
|
|
static_assert(FCmpInst::FCMP_UNO == 8, ""); // 1 0 0 0
|
|
static_assert(FCmpInst::FCMP_UEQ == 9, ""); // 1 0 0 1
|
|
static_assert(FCmpInst::FCMP_UGT == 10, ""); // 1 0 1 0
|
|
static_assert(FCmpInst::FCMP_UGE == 11, ""); // 1 0 1 1
|
|
static_assert(FCmpInst::FCMP_ULT == 12, ""); // 1 1 0 0
|
|
static_assert(FCmpInst::FCMP_ULE == 13, ""); // 1 1 0 1
|
|
static_assert(FCmpInst::FCMP_UNE == 14, ""); // 1 1 1 0
|
|
static_assert(FCmpInst::FCMP_TRUE == 15, ""); // 1 1 1 1
|
|
return CC;
|
|
}
|
|
|
|
/// 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(bool Sign, unsigned Code, Value *LHS, Value *RHS,
|
|
InstCombiner::BuilderTy &Builder) {
|
|
ICmpInst::Predicate NewPred;
|
|
if (Value *NewConstant = getICmpValue(Sign, Code, LHS, RHS, NewPred))
|
|
return NewConstant;
|
|
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) {
|
|
const auto Pred = static_cast<FCmpInst::Predicate>(Code);
|
|
assert(FCmpInst::FCMP_FALSE <= Pred && Pred <= FCmpInst::FCMP_TRUE &&
|
|
"Unexpected FCmp predicate!");
|
|
if (Pred == FCmpInst::FCMP_FALSE)
|
|
return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
|
|
if (Pred == FCmpInst::FCMP_TRUE)
|
|
return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 1);
|
|
return Builder.CreateFCmp(Pred, LHS, RHS);
|
|
}
|
|
|
|
/// Transform BITWISE_OP(BSWAP(A),BSWAP(B)) or
|
|
/// BITWISE_OP(BSWAP(A), Constant) to BSWAP(BITWISE_OP(A, B))
|
|
/// \param I Binary operator to transform.
|
|
/// \return Pointer to node that must replace the original binary operator, or
|
|
/// null pointer if no transformation was made.
|
|
static Value *SimplifyBSwap(BinaryOperator &I,
|
|
InstCombiner::BuilderTy &Builder) {
|
|
assert(I.isBitwiseLogicOp() && "Unexpected opcode for bswap simplifying");
|
|
|
|
Value *OldLHS = I.getOperand(0);
|
|
Value *OldRHS = I.getOperand(1);
|
|
|
|
Value *NewLHS;
|
|
if (!match(OldLHS, m_BSwap(m_Value(NewLHS))))
|
|
return nullptr;
|
|
|
|
Value *NewRHS;
|
|
const APInt *C;
|
|
|
|
if (match(OldRHS, m_BSwap(m_Value(NewRHS)))) {
|
|
// OP( BSWAP(x), BSWAP(y) ) -> BSWAP( OP(x, y) )
|
|
if (!OldLHS->hasOneUse() && !OldRHS->hasOneUse())
|
|
return nullptr;
|
|
// NewRHS initialized by the matcher.
|
|
} else if (match(OldRHS, m_APInt(C))) {
|
|
// OP( BSWAP(x), CONSTANT ) -> BSWAP( OP(x, BSWAP(CONSTANT) ) )
|
|
if (!OldLHS->hasOneUse())
|
|
return nullptr;
|
|
NewRHS = ConstantInt::get(I.getType(), C->byteSwap());
|
|
} else
|
|
return nullptr;
|
|
|
|
Value *BinOp = Builder.CreateBinOp(I.getOpcode(), NewLHS, NewRHS);
|
|
Function *F = Intrinsic::getDeclaration(I.getModule(), Intrinsic::bswap,
|
|
I.getType());
|
|
return Builder.CreateCall(F, BinOp);
|
|
}
|
|
|
|
/// This handles expressions of the form ((val OP C1) & C2). Where
|
|
/// the Op parameter is 'OP', OpRHS is 'C1', and AndRHS is 'C2'.
|
|
Instruction *InstCombiner::OptAndOp(BinaryOperator *Op,
|
|
ConstantInt *OpRHS,
|
|
ConstantInt *AndRHS,
|
|
BinaryOperator &TheAnd) {
|
|
Value *X = Op->getOperand(0);
|
|
|
|
switch (Op->getOpcode()) {
|
|
default: break;
|
|
case Instruction::Add:
|
|
if (Op->hasOneUse()) {
|
|
// Adding a one to a single bit bit-field should be turned into an XOR
|
|
// of the bit. First thing to check is to see if this AND is with a
|
|
// single bit constant.
|
|
const APInt &AndRHSV = AndRHS->getValue();
|
|
|
|
// If there is only one bit set.
|
|
if (AndRHSV.isPowerOf2()) {
|
|
// Ok, at this point, we know that we are masking the result of the
|
|
// ADD down to exactly one bit. If the constant we are adding has
|
|
// no bits set below this bit, then we can eliminate the ADD.
|
|
const APInt& AddRHS = OpRHS->getValue();
|
|
|
|
// Check to see if any bits below the one bit set in AndRHSV are set.
|
|
if ((AddRHS & (AndRHSV - 1)).isNullValue()) {
|
|
// If not, the only thing that can effect the output of the AND is
|
|
// the bit specified by AndRHSV. If that bit is set, the effect of
|
|
// the XOR is to toggle the bit. If it is clear, then the ADD has
|
|
// no effect.
|
|
if ((AddRHS & AndRHSV).isNullValue()) { // Bit is not set, noop
|
|
TheAnd.setOperand(0, X);
|
|
return &TheAnd;
|
|
} else {
|
|
// Pull the XOR out of the AND.
|
|
Value *NewAnd = Builder.CreateAnd(X, AndRHS);
|
|
NewAnd->takeName(Op);
|
|
return BinaryOperator::CreateXor(NewAnd, AndRHS);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
return nullptr;
|
|
}
|
|
|
|
/// 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 *InstCombiner::insertRangeTest(Value *V, const APInt &Lo, const APInt &Hi,
|
|
bool isSigned, bool Inside) {
|
|
assert((isSigned ? Lo.sle(Hi) : Lo.ule(Hi)) &&
|
|
"Lo is not <= Hi in range emission code!");
|
|
|
|
Type *Ty = V->getType();
|
|
if (Lo == Hi)
|
|
return Inside ? ConstantInt::getFalse(Ty) : ConstantInt::getTrue(Ty);
|
|
|
|
// 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) {
|
|
ConstantInt *ACst = dyn_cast<ConstantInt>(A);
|
|
ConstantInt *BCst = dyn_cast<ConstantInt>(B);
|
|
ConstantInt *CCst = dyn_cast<ConstantInt>(C);
|
|
bool IsEq = (Pred == ICmpInst::ICMP_EQ);
|
|
bool IsAPow2 = (ACst && !ACst->isZero() && ACst->getValue().isPowerOf2());
|
|
bool IsBPow2 = (BCst && !BCst->isZero() && BCst->getValue().isPowerOf2());
|
|
unsigned MaskVal = 0;
|
|
if (CCst && CCst->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 (ACst && CCst && ConstantExpr::getAnd(ACst, CCst) == CCst) {
|
|
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 (BCst && CCst && ConstantExpr::getAnd(BCst, CCst) == CCst) {
|
|
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 *LHS, Value *RHS, CmpInst::Predicate &Pred,
|
|
Value *&X, Value *&Y, Value *&Z) {
|
|
APInt Mask;
|
|
if (!llvm::decomposeBitTestICmp(LHS, RHS, Pred, X, Mask))
|
|
return false;
|
|
|
|
Y = ConstantInt::get(X->getType(), Mask);
|
|
Z = ConstantInt::get(X->getType(), 0);
|
|
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
|
|
Optional<std::pair<unsigned, unsigned>>
|
|
getMaskedTypeForICmpPair(Value *&A, Value *&B, Value *&C,
|
|
Value *&D, Value *&E, ICmpInst *LHS,
|
|
ICmpInst *RHS,
|
|
ICmpInst::Predicate &PredL,
|
|
ICmpInst::Predicate &PredR) {
|
|
// vectors are not (yet?) supported. Don't support pointers either.
|
|
if (!LHS->getOperand(0)->getType()->isIntegerTy() ||
|
|
!RHS->getOperand(0)->getType()->isIntegerTy())
|
|
return None;
|
|
|
|
// 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.
|
|
Value *L1 = LHS->getOperand(0);
|
|
Value *L2 = LHS->getOperand(1);
|
|
Value *L11, *L12, *L21, *L22;
|
|
// Check whether the icmp can be decomposed into a bit test.
|
|
if (decomposeBitTestICmp(L1, L2, PredL, L11, L12, L2)) {
|
|
L21 = L22 = L1 = nullptr;
|
|
} else {
|
|
// 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 None;
|
|
|
|
Value *R1 = RHS->getOperand(0);
|
|
Value *R2 = RHS->getOperand(1);
|
|
Value *R11, *R12;
|
|
bool Ok = false;
|
|
if (decomposeBitTestICmp(R1, R2, 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 None;
|
|
}
|
|
E = R2;
|
|
R1 = nullptr;
|
|
Ok = true;
|
|
} else {
|
|
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;
|
|
}
|
|
}
|
|
|
|
// Bail if RHS was a icmp that can't be decomposed into an equality.
|
|
if (!ICmpInst::isEquality(PredR))
|
|
return None;
|
|
|
|
// 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;
|
|
Ok = true;
|
|
} else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) {
|
|
A = R12;
|
|
D = R11;
|
|
E = R1;
|
|
Ok = true;
|
|
} else {
|
|
return None;
|
|
}
|
|
}
|
|
if (!Ok)
|
|
return None;
|
|
|
|
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 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).
|
|
static Value * foldLogOpOfMaskedICmps_NotAllZeros_BMask_Mixed(
|
|
ICmpInst *LHS, ICmpInst *RHS, bool IsAnd,
|
|
Value *A, Value *B, Value *C, Value *D, Value *E,
|
|
ICmpInst::Predicate PredL, ICmpInst::Predicate PredR,
|
|
llvm::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.
|
|
//
|
|
ConstantInt *BCst = dyn_cast<ConstantInt>(B);
|
|
if (!BCst)
|
|
return nullptr;
|
|
ConstantInt *CCst = dyn_cast<ConstantInt>(C);
|
|
if (!CCst)
|
|
return nullptr;
|
|
ConstantInt *DCst = dyn_cast<ConstantInt>(D);
|
|
if (!DCst)
|
|
return nullptr;
|
|
ConstantInt *ECst = dyn_cast<ConstantInt>(E);
|
|
if (!ECst)
|
|
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).
|
|
if (PredR != NewCC)
|
|
ECst = cast<ConstantInt>(ConstantExpr::getXor(DCst, ECst));
|
|
|
|
// 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->getValue() == 0 || DCst->getValue() == 0)
|
|
return nullptr;
|
|
|
|
// If B and D don't intersect, ie. (B & D) == 0, no folding because we can't
|
|
// deduce anything from it.
|
|
// For example,
|
|
// (icmp ne (A & 12), 0) & (icmp eq (A & 3), 1) -> no folding.
|
|
if ((BCst->getValue() & DCst->getValue()) == 0)
|
|
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->getValue() & DCst->getValue()) & ECst->getValue()) == 0) &&
|
|
(BCst->getValue() & (BCst->getValue() ^ DCst->getValue())).isPowerOf2()) {
|
|
APInt BorD = BCst->getValue() | DCst->getValue();
|
|
APInt BandBxorDorE = (BCst->getValue() & (BCst->getValue() ^ DCst->getValue())) |
|
|
ECst->getValue();
|
|
Value *NewMask = ConstantInt::get(BCst->getType(), BorD);
|
|
Value *NewMaskedValue = ConstantInt::get(BCst->getType(), BandBxorDorE);
|
|
Value *NewAnd = Builder.CreateAnd(A, NewMask);
|
|
return Builder.CreateICmp(NewCC, NewAnd, NewMaskedValue);
|
|
}
|
|
|
|
auto IsSubSetOrEqual = [](ConstantInt *C1, ConstantInt *C2) {
|
|
return (C1->getValue() & C2->getValue()) == C1->getValue();
|
|
};
|
|
auto IsSuperSetOrEqual = [](ConstantInt *C1, ConstantInt *C2) {
|
|
return (C1->getValue() & C2->getValue()) == C2->getValue();
|
|
};
|
|
|
|
// 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))
|
|
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->getValue() & ECst->getValue()) != 0)
|
|
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.
|
|
static Value *foldLogOpOfMaskedICmpsAsymmetric(
|
|
ICmpInst *LHS, ICmpInst *RHS, bool IsAnd,
|
|
Value *A, Value *B, Value *C, Value *D, Value *E,
|
|
ICmpInst::Predicate PredL, ICmpInst::Predicate PredR,
|
|
unsigned LHSMask, unsigned RHSMask,
|
|
llvm::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, C, 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, E, 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(ICmpInst *LHS, ICmpInst *RHS, bool IsAnd,
|
|
llvm::InstCombiner::BuilderTy &Builder) {
|
|
Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr, *E = nullptr;
|
|
ICmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
|
|
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)
|
|
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))
|
|
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)
|
|
Value *NewAnd1 = Builder.CreateAnd(B, D);
|
|
Value *NewAnd2 = Builder.CreateAnd(A, NewAnd1);
|
|
return Builder.CreateICmp(NewCC, NewAnd2, A);
|
|
}
|
|
|
|
// Remaining cases assume at least that B and D are constant, and depend on
|
|
// their actual values. This isn't strictly necessary, just a "handle the
|
|
// easy cases for now" decision.
|
|
ConstantInt *BCst = dyn_cast<ConstantInt>(B);
|
|
if (!BCst)
|
|
return nullptr;
|
|
ConstantInt *DCst = dyn_cast<ConstantInt>(D);
|
|
if (!DCst)
|
|
return nullptr;
|
|
|
|
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 = BCst->getValue() & DCst->getValue();
|
|
|
|
if (NewMask == BCst->getValue())
|
|
return LHS;
|
|
else if (NewMask == DCst->getValue())
|
|
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 = BCst->getValue() | DCst->getValue();
|
|
|
|
if (NewMask == BCst->getValue())
|
|
return LHS;
|
|
else if (NewMask == DCst->getValue())
|
|
return RHS;
|
|
}
|
|
|
|
if (Mask & BMask_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.
|
|
ConstantInt *CCst = dyn_cast<ConstantInt>(C);
|
|
if (!CCst)
|
|
return nullptr;
|
|
ConstantInt *ECst = dyn_cast<ConstantInt>(E);
|
|
if (!ECst)
|
|
return nullptr;
|
|
if (PredL != NewCC)
|
|
CCst = cast<ConstantInt>(ConstantExpr::getXor(BCst, CCst));
|
|
if (PredR != NewCC)
|
|
ECst = cast<ConstantInt>(ConstantExpr::getXor(DCst, ECst));
|
|
|
|
// If there is a conflict, we should actually return a false for the
|
|
// whole construct.
|
|
if (((BCst->getValue() & DCst->getValue()) &
|
|
(CCst->getValue() ^ ECst->getValue())).getBoolValue())
|
|
return ConstantInt::get(LHS->getType(), !IsAnd);
|
|
|
|
Value *NewOr1 = Builder.CreateOr(B, D);
|
|
Value *NewOr2 = ConstantExpr::getOr(CCst, ECst);
|
|
Value *NewAnd = Builder.CreateAnd(A, NewOr1);
|
|
return Builder.CreateICmp(NewCC, NewAnd, NewOr2);
|
|
}
|
|
|
|
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 *InstCombiner::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 *RangeEnd;
|
|
if (Cmp1->getOperand(0) == Input) {
|
|
// For the upper range compare we have: icmp x, n
|
|
RangeEnd = Cmp1->getOperand(1);
|
|
} else if (Cmp1->getOperand(1) == Input) {
|
|
// For the upper range compare we have: icmp n, x
|
|
RangeEnd = Cmp1->getOperand(0);
|
|
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);
|
|
}
|
|
|
|
static Value *
|
|
foldAndOrOfEqualityCmpsWithConstants(ICmpInst *LHS, ICmpInst *RHS,
|
|
bool JoinedByAnd,
|
|
InstCombiner::BuilderTy &Builder) {
|
|
Value *X = LHS->getOperand(0);
|
|
if (X != RHS->getOperand(0))
|
|
return nullptr;
|
|
|
|
const APInt *C1, *C2;
|
|
if (!match(LHS->getOperand(1), m_APInt(C1)) ||
|
|
!match(RHS->getOperand(1), m_APInt(C2)))
|
|
return nullptr;
|
|
|
|
// We only handle (X != C1 && X != C2) and (X == C1 || X == C2).
|
|
ICmpInst::Predicate Pred = LHS->getPredicate();
|
|
if (Pred != RHS->getPredicate())
|
|
return nullptr;
|
|
if (JoinedByAnd && Pred != ICmpInst::ICMP_NE)
|
|
return nullptr;
|
|
if (!JoinedByAnd && Pred != ICmpInst::ICMP_EQ)
|
|
return nullptr;
|
|
|
|
// The larger unsigned constant goes on the right.
|
|
if (C1->ugt(*C2))
|
|
std::swap(C1, C2);
|
|
|
|
APInt Xor = *C1 ^ *C2;
|
|
if (Xor.isPowerOf2()) {
|
|
// If LHSC and RHSC differ by only one bit, then set that bit in X and
|
|
// compare against the larger constant:
|
|
// (X == C1 || X == C2) --> (X | (C1 ^ C2)) == C2
|
|
// (X != C1 && X != C2) --> (X | (C1 ^ C2)) != C2
|
|
// We choose an 'or' with a Pow2 constant rather than the inverse mask with
|
|
// 'and' because that may lead to smaller codegen from a smaller constant.
|
|
Value *Or = Builder.CreateOr(X, ConstantInt::get(X->getType(), Xor));
|
|
return Builder.CreateICmp(Pred, Or, ConstantInt::get(X->getType(), *C2));
|
|
}
|
|
|
|
// Special case: get the ordering right when the values wrap around zero.
|
|
// Ie, we assumed the constants were unsigned when swapping earlier.
|
|
if (C1->isNullValue() && C2->isAllOnesValue())
|
|
std::swap(C1, C2);
|
|
|
|
if (*C1 == *C2 - 1) {
|
|
// (X == 13 || X == 14) --> X - 13 <=u 1
|
|
// (X != 13 && X != 14) --> X - 13 >u 1
|
|
// An 'add' is the canonical IR form, so favor that over a 'sub'.
|
|
Value *Add = Builder.CreateAdd(X, ConstantInt::get(X->getType(), -(*C1)));
|
|
auto NewPred = JoinedByAnd ? ICmpInst::ICMP_UGT : ICmpInst::ICMP_ULE;
|
|
return Builder.CreateICmp(NewPred, Add, ConstantInt::get(X->getType(), 1));
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
// Fold (iszero(A & K1) | iszero(A & K2)) -> (A & (K1 | K2)) != (K1 | K2)
|
|
// Fold (!iszero(A & K1) & !iszero(A & K2)) -> (A & (K1 | K2)) == (K1 | K2)
|
|
Value *InstCombiner::foldAndOrOfICmpsOfAndWithPow2(ICmpInst *LHS, ICmpInst *RHS,
|
|
bool JoinedByAnd,
|
|
Instruction &CxtI) {
|
|
ICmpInst::Predicate Pred = LHS->getPredicate();
|
|
if (Pred != RHS->getPredicate())
|
|
return nullptr;
|
|
if (JoinedByAnd && Pred != ICmpInst::ICMP_NE)
|
|
return nullptr;
|
|
if (!JoinedByAnd && Pred != ICmpInst::ICMP_EQ)
|
|
return nullptr;
|
|
|
|
// TODO support vector splats
|
|
ConstantInt *LHSC = dyn_cast<ConstantInt>(LHS->getOperand(1));
|
|
ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS->getOperand(1));
|
|
if (!LHSC || !RHSC || !LHSC->isZero() || !RHSC->isZero())
|
|
return nullptr;
|
|
|
|
Value *A, *B, *C, *D;
|
|
if (match(LHS->getOperand(0), m_And(m_Value(A), m_Value(B))) &&
|
|
match(RHS->getOperand(0), m_And(m_Value(C), m_Value(D)))) {
|
|
if (A == D || B == D)
|
|
std::swap(C, D);
|
|
if (B == C)
|
|
std::swap(A, B);
|
|
|
|
if (A == C &&
|
|
isKnownToBeAPowerOfTwo(B, false, 0, &CxtI) &&
|
|
isKnownToBeAPowerOfTwo(D, false, 0, &CxtI)) {
|
|
Value *Mask = Builder.CreateOr(B, D);
|
|
Value *Masked = Builder.CreateAnd(A, Mask);
|
|
auto NewPred = JoinedByAnd ? ICmpInst::ICMP_EQ : ICmpInst::ICMP_NE;
|
|
return Builder.CreateICmp(NewPred, Masked, Mask);
|
|
}
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
/// 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 {
|
|
CmpInst::Predicate Pred;
|
|
const APInt *I01, *I1; // powers of two; I1 == I01 << 1
|
|
if (!(match(ICmp,
|
|
m_ICmp(Pred, m_Add(m_Value(X), m_Power2(I01)), m_Power2(I1))) &&
|
|
Pred == ICmpInst::ICMP_ULT && 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 {
|
|
CmpInst::Predicate Pred = ICmp->getPredicate();
|
|
// Can it be decomposed into icmp eq (X & Mask), 0 ?
|
|
if (llvm::decomposeBitTestICmp(ICmp->getOperand(0), ICmp->getOperand(1),
|
|
Pred, X, UnsetBitsMask,
|
|
/*LookThruTrunc=*/false) &&
|
|
Pred == ICmpInst::ICMP_EQ)
|
|
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.isNullValue() && "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)&(icmp) if possible.
|
|
Value *InstCombiner::foldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS,
|
|
Instruction &CxtI) {
|
|
// Fold (!iszero(A & K1) & !iszero(A & K2)) -> (A & (K1 | K2)) == (K1 | K2)
|
|
// if K1 and K2 are a one-bit mask.
|
|
if (Value *V = foldAndOrOfICmpsOfAndWithPow2(LHS, RHS, true, CxtI))
|
|
return V;
|
|
|
|
ICmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
|
|
|
|
// (icmp1 A, B) & (icmp2 A, B) --> (icmp3 A, B)
|
|
if (PredicatesFoldable(PredL, PredR)) {
|
|
if (LHS->getOperand(0) == RHS->getOperand(1) &&
|
|
LHS->getOperand(1) == RHS->getOperand(0))
|
|
LHS->swapOperands();
|
|
if (LHS->getOperand(0) == RHS->getOperand(0) &&
|
|
LHS->getOperand(1) == RHS->getOperand(1)) {
|
|
Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1);
|
|
unsigned Code = getICmpCode(LHS) & getICmpCode(RHS);
|
|
bool isSigned = LHS->isSigned() || RHS->isSigned();
|
|
return getNewICmpValue(isSigned, Code, Op0, Op1, Builder);
|
|
}
|
|
}
|
|
|
|
// handle (roughly): (icmp eq (A & B), C) & (icmp eq (A & D), E)
|
|
if (Value *V = foldLogOpOfMaskedICmps(LHS, RHS, true, Builder))
|
|
return V;
|
|
|
|
// E.g. (icmp sge x, 0) & (icmp slt x, n) --> icmp ult x, n
|
|
if (Value *V = simplifyRangeCheck(LHS, RHS, /*Inverted=*/false))
|
|
return V;
|
|
|
|
// E.g. (icmp slt x, n) & (icmp sge x, 0) --> icmp ult x, n
|
|
if (Value *V = simplifyRangeCheck(RHS, LHS, /*Inverted=*/false))
|
|
return V;
|
|
|
|
if (Value *V = foldAndOrOfEqualityCmpsWithConstants(LHS, RHS, true, Builder))
|
|
return V;
|
|
|
|
if (Value *V = foldSignedTruncationCheck(LHS, RHS, CxtI, Builder))
|
|
return V;
|
|
|
|
// This only handles icmp of constants: (icmp1 A, C1) & (icmp2 B, C2).
|
|
Value *LHS0 = LHS->getOperand(0), *RHS0 = RHS->getOperand(0);
|
|
ConstantInt *LHSC = dyn_cast<ConstantInt>(LHS->getOperand(1));
|
|
ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS->getOperand(1));
|
|
if (!LHSC || !RHSC)
|
|
return nullptr;
|
|
|
|
if (LHSC == RHSC && PredL == PredR) {
|
|
// (icmp ult A, C) & (icmp ult B, C) --> (icmp ult (A|B), C)
|
|
// where C is a power of 2 or
|
|
// (icmp eq A, 0) & (icmp eq B, 0) --> (icmp eq (A|B), 0)
|
|
if ((PredL == ICmpInst::ICMP_ULT && LHSC->getValue().isPowerOf2()) ||
|
|
(PredL == ICmpInst::ICMP_EQ && LHSC->isZero())) {
|
|
Value *NewOr = Builder.CreateOr(LHS0, RHS0);
|
|
return Builder.CreateICmp(PredL, NewOr, LHSC);
|
|
}
|
|
}
|
|
|
|
// (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 == ICmpInst::ICMP_EQ && PredL == PredR && LHS->hasOneUse() &&
|
|
RHS->hasOneUse()) {
|
|
Value *V;
|
|
ConstantInt *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_ConstantInt(AndC)))) {
|
|
SmallC = RHSC;
|
|
BigC = LHSC;
|
|
} else if (match(LHS0, m_Trunc(m_Value(V))) &&
|
|
match(RHS0, m_And(m_Specific(V), m_ConstantInt(AndC)))) {
|
|
SmallC = LHSC;
|
|
BigC = RHSC;
|
|
}
|
|
|
|
if (SmallC && BigC) {
|
|
unsigned BigBitSize = BigC->getType()->getBitWidth();
|
|
unsigned SmallBitSize = SmallC->getType()->getBitWidth();
|
|
|
|
// Check that the low bits are zero.
|
|
APInt Low = APInt::getLowBitsSet(BigBitSize, SmallBitSize);
|
|
if ((Low & AndC->getValue()).isNullValue() &&
|
|
(Low & BigC->getValue()).isNullValue()) {
|
|
Value *NewAnd = Builder.CreateAnd(V, Low | AndC->getValue());
|
|
APInt N = SmallC->getValue().zext(BigBitSize) | BigC->getValue();
|
|
Value *NewVal = ConstantInt::get(AndC->getType()->getContext(), N);
|
|
return Builder.CreateICmp(PredL, NewAnd, NewVal);
|
|
}
|
|
}
|
|
}
|
|
|
|
// From here on, we only handle:
|
|
// (icmp1 A, C1) & (icmp2 A, C2) --> something simpler.
|
|
if (LHS0 != RHS0)
|
|
return nullptr;
|
|
|
|
// ICMP_[US][GL]E X, C is folded to ICMP_[US][GL]T elsewhere.
|
|
if (PredL == ICmpInst::ICMP_UGE || PredL == ICmpInst::ICMP_ULE ||
|
|
PredR == ICmpInst::ICMP_UGE || PredR == ICmpInst::ICMP_ULE ||
|
|
PredL == ICmpInst::ICMP_SGE || PredL == ICmpInst::ICMP_SLE ||
|
|
PredR == ICmpInst::ICMP_SGE || PredR == ICmpInst::ICMP_SLE)
|
|
return nullptr;
|
|
|
|
// We can't fold (ugt x, C) & (sgt x, C2).
|
|
if (!PredicatesFoldable(PredL, PredR))
|
|
return nullptr;
|
|
|
|
// Ensure that the larger constant is on the RHS.
|
|
bool ShouldSwap;
|
|
if (CmpInst::isSigned(PredL) ||
|
|
(ICmpInst::isEquality(PredL) && CmpInst::isSigned(PredR)))
|
|
ShouldSwap = LHSC->getValue().sgt(RHSC->getValue());
|
|
else
|
|
ShouldSwap = LHSC->getValue().ugt(RHSC->getValue());
|
|
|
|
if (ShouldSwap) {
|
|
std::swap(LHS, RHS);
|
|
std::swap(LHSC, RHSC);
|
|
std::swap(PredL, PredR);
|
|
}
|
|
|
|
// At this point, we know we have two icmp instructions
|
|
// comparing a value against two constants and and'ing the result
|
|
// together. Because of the above check, we know that we only have
|
|
// icmp eq, icmp ne, icmp [su]lt, and icmp [SU]gt here. We also know
|
|
// (from the icmp folding check above), that the two constants
|
|
// are not equal and that the larger constant is on the RHS
|
|
assert(LHSC != RHSC && "Compares not folded above?");
|
|
|
|
switch (PredL) {
|
|
default:
|
|
llvm_unreachable("Unknown integer condition code!");
|
|
case ICmpInst::ICMP_NE:
|
|
switch (PredR) {
|
|
default:
|
|
llvm_unreachable("Unknown integer condition code!");
|
|
case ICmpInst::ICMP_ULT:
|
|
if (LHSC == SubOne(RHSC)) // (X != 13 & X u< 14) -> X < 13
|
|
return Builder.CreateICmpULT(LHS0, LHSC);
|
|
if (LHSC->isZero()) // (X != 0 & X u< 14) -> X-1 u< 13
|
|
return insertRangeTest(LHS0, LHSC->getValue() + 1, RHSC->getValue(),
|
|
false, true);
|
|
break; // (X != 13 & X u< 15) -> no change
|
|
case ICmpInst::ICMP_SLT:
|
|
if (LHSC == SubOne(RHSC)) // (X != 13 & X s< 14) -> X < 13
|
|
return Builder.CreateICmpSLT(LHS0, LHSC);
|
|
break; // (X != 13 & X s< 15) -> no change
|
|
case ICmpInst::ICMP_NE:
|
|
// Potential folds for this case should already be handled.
|
|
break;
|
|
}
|
|
break;
|
|
case ICmpInst::ICMP_UGT:
|
|
switch (PredR) {
|
|
default:
|
|
llvm_unreachable("Unknown integer condition code!");
|
|
case ICmpInst::ICMP_NE:
|
|
if (RHSC == AddOne(LHSC)) // (X u> 13 & X != 14) -> X u> 14
|
|
return Builder.CreateICmp(PredL, LHS0, RHSC);
|
|
break; // (X u> 13 & X != 15) -> no change
|
|
case ICmpInst::ICMP_ULT: // (X u> 13 & X u< 15) -> (X-14) <u 1
|
|
return insertRangeTest(LHS0, LHSC->getValue() + 1, RHSC->getValue(),
|
|
false, true);
|
|
}
|
|
break;
|
|
case ICmpInst::ICMP_SGT:
|
|
switch (PredR) {
|
|
default:
|
|
llvm_unreachable("Unknown integer condition code!");
|
|
case ICmpInst::ICMP_NE:
|
|
if (RHSC == AddOne(LHSC)) // (X s> 13 & X != 14) -> X s> 14
|
|
return Builder.CreateICmp(PredL, LHS0, RHSC);
|
|
break; // (X s> 13 & X != 15) -> no change
|
|
case ICmpInst::ICMP_SLT: // (X s> 13 & X s< 15) -> (X-14) s< 1
|
|
return insertRangeTest(LHS0, LHSC->getValue() + 1, RHSC->getValue(), true,
|
|
true);
|
|
}
|
|
break;
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
Value *InstCombiner::foldLogicOfFCmps(FCmpInst *LHS, FCmpInst *RHS, bool IsAnd) {
|
|
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;
|
|
return getFCmpValue(NewPred, LHS0, LHS1, Builder);
|
|
}
|
|
|
|
if ((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.CreateFCmp(PredL, LHS0, RHS0);
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
/// Match De Morgan's Laws:
|
|
/// (~A & ~B) == (~(A | B))
|
|
/// (~A | ~B) == (~(A & B))
|
|
static Instruction *matchDeMorgansLaws(BinaryOperator &I,
|
|
InstCombiner::BuilderTy &Builder) {
|
|
auto 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.
|
|
Opcode = (Opcode == Instruction::And) ? Instruction::Or : Instruction::And;
|
|
|
|
Value *A, *B;
|
|
if (match(I.getOperand(0), m_OneUse(m_Not(m_Value(A)))) &&
|
|
match(I.getOperand(1), m_OneUse(m_Not(m_Value(B)))) &&
|
|
!IsFreeToInvert(A, A->hasOneUse()) &&
|
|
!IsFreeToInvert(B, B->hasOneUse())) {
|
|
Value *AndOr = Builder.CreateBinOp(Opcode, A, B, I.getName() + ".demorgan");
|
|
return BinaryOperator::CreateNot(AndOr);
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
bool InstCombiner::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,
|
|
InstCombiner::BuilderTy &Builder) {
|
|
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))))) {
|
|
Constant *TruncC = ConstantExpr::getTrunc(C, SrcTy);
|
|
Constant *ZextTruncC = ConstantExpr::getZExt(TruncC, DestTy);
|
|
if (ZextTruncC == C) {
|
|
// LogicOpc (zext X), C --> zext (LogicOpc X, C)
|
|
Value *NewOp = Builder.CreateBinOp(LogicOpc, X, TruncC);
|
|
return new ZExtInst(NewOp, DestTy);
|
|
}
|
|
}
|
|
|
|
if (match(Cast, m_OneUse(m_SExt(m_Value(X))))) {
|
|
Constant *TruncC = ConstantExpr::getTrunc(C, SrcTy);
|
|
Constant *SextTruncC = ConstantExpr::getSExt(TruncC, DestTy);
|
|
if (SextTruncC == C) {
|
|
// LogicOpc (sext X), C --> sext (LogicOpc X, C)
|
|
Value *NewOp = Builder.CreateBinOp(LogicOpc, X, TruncC);
|
|
return new SExtInst(NewOp, DestTy);
|
|
}
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
/// Fold {and,or,xor} (cast X), Y.
|
|
Instruction *InstCombiner::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);
|
|
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, Builder))
|
|
return Ret;
|
|
|
|
CastInst *Cast1 = dyn_cast<CastInst>(Op1);
|
|
if (!Cast1)
|
|
return nullptr;
|
|
|
|
// Both operands of the logic operation are casts. The casts must be of the
|
|
// same type for reduction.
|
|
auto CastOpcode = Cast0->getOpcode();
|
|
if (CastOpcode != Cast1->getOpcode() || SrcTy != Cast1->getSrcTy())
|
|
return nullptr;
|
|
|
|
Value *Cast0Src = Cast0->getOperand(0);
|
|
Value *Cast1Src = Cast1->getOperand(0);
|
|
|
|
// fold logic(cast(A), cast(B)) -> cast(logic(A, B))
|
|
if (shouldOptimizeCast(Cast0) && shouldOptimizeCast(Cast1)) {
|
|
Value *NewOp = Builder.CreateBinOp(LogicOpc, Cast0Src, Cast1Src,
|
|
I.getName());
|
|
return CastInst::Create(CastOpcode, NewOp, DestTy);
|
|
}
|
|
|
|
// For now, only 'and'/'or' have optimizations after this.
|
|
if (LogicOpc == Instruction::Xor)
|
|
return nullptr;
|
|
|
|
// If this is logic(cast(icmp), cast(icmp)), try to fold this even if the
|
|
// cast is otherwise not optimizable. This happens for vector sexts.
|
|
ICmpInst *ICmp0 = dyn_cast<ICmpInst>(Cast0Src);
|
|
ICmpInst *ICmp1 = dyn_cast<ICmpInst>(Cast1Src);
|
|
if (ICmp0 && ICmp1) {
|
|
Value *Res = LogicOpc == Instruction::And ? foldAndOfICmps(ICmp0, ICmp1, I)
|
|
: foldOrOfICmps(ICmp0, ICmp1, I);
|
|
if (Res)
|
|
return CastInst::Create(CastOpcode, Res, DestTy);
|
|
return nullptr;
|
|
}
|
|
|
|
// If this is logic(cast(fcmp), cast(fcmp)), try to fold this even if the
|
|
// cast is otherwise not optimizable. This happens for vector sexts.
|
|
FCmpInst *FCmp0 = dyn_cast<FCmpInst>(Cast0Src);
|
|
FCmpInst *FCmp1 = dyn_cast<FCmpInst>(Cast1Src);
|
|
if (FCmp0 && FCmp1)
|
|
if (Value *R = foldLogicOfFCmps(FCmp0, FCmp1, LogicOpc == Instruction::And))
|
|
return CastInst::Create(CastOpcode, R, 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));
|
|
|
|
// (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) {
|
|
if (auto *ScalarC = dyn_cast<ConstantInt>(C))
|
|
return ScalarC->getZExtValue() < BitWidth;
|
|
|
|
if (C->getType()->isVectorTy()) {
|
|
// Check each element of a constant vector.
|
|
unsigned NumElts = C->getType()->getVectorNumElements();
|
|
for (unsigned i = 0; i != NumElts; ++i) {
|
|
Constant *Elt = C->getAggregateElement(i);
|
|
if (!Elt)
|
|
return false;
|
|
if (isa<UndefValue>(Elt))
|
|
continue;
|
|
auto *CI = dyn_cast<ConstantInt>(Elt);
|
|
if (!CI || CI->getZExtValue() >= BitWidth)
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
// The constant is a constant expression or unknown.
|
|
return false;
|
|
}
|
|
|
|
/// 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 *InstCombiner::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);
|
|
}
|
|
|
|
// 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 *InstCombiner::visitAnd(BinaryOperator &I) {
|
|
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;
|
|
|
|
// 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;
|
|
|
|
// (A|B)&(A|C) -> A|(B&C) etc
|
|
if (Value *V = SimplifyUsingDistributiveLaws(I))
|
|
return replaceInstUsesWith(I, V);
|
|
|
|
if (Value *V = SimplifyBSwap(I, Builder))
|
|
return replaceInstUsesWith(I, V);
|
|
|
|
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
|
const APInt *C;
|
|
if (match(Op1, m_APInt(C))) {
|
|
Value *X, *Y;
|
|
if (match(Op0, m_OneUse(m_LogicalShift(m_One(), m_Value(X)))) &&
|
|
C->isOneValue()) {
|
|
// (1 << X) & 1 --> zext(X == 0)
|
|
// (1 >> X) & 1 --> zext(X == 0)
|
|
Value *IsZero = Builder.CreateICmpEQ(X, ConstantInt::get(I.getType(), 0));
|
|
return new ZExtInst(IsZero, I.getType());
|
|
}
|
|
|
|
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(I.getType(), *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(I.getType(),
|
|
Together ^ *C));
|
|
And->takeName(Op0);
|
|
return BinaryOperator::CreateOr(And, ConstantInt::get(I.getType(),
|
|
Together));
|
|
}
|
|
|
|
// 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);
|
|
}
|
|
}
|
|
|
|
}
|
|
|
|
if (ConstantInt *AndRHS = dyn_cast<ConstantInt>(Op1)) {
|
|
const APInt &AndRHSMask = AndRHS->getValue();
|
|
|
|
// Optimize a variety of ((val OP C1) & C2) combinations...
|
|
if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
|
|
// ((C1 OP zext(X)) & C2) -> zext((C1-X) & C2) if C2 fits in the bitwidth
|
|
// of X and OP behaves well when given trunc(C1) and X.
|
|
switch (Op0I->getOpcode()) {
|
|
default:
|
|
break;
|
|
case Instruction::Xor:
|
|
case Instruction::Or:
|
|
case Instruction::Mul:
|
|
case Instruction::Add:
|
|
case Instruction::Sub:
|
|
Value *X;
|
|
ConstantInt *C1;
|
|
if (match(Op0I, m_c_BinOp(m_ZExt(m_Value(X)), m_ConstantInt(C1)))) {
|
|
if (AndRHSMask.isIntN(X->getType()->getScalarSizeInBits())) {
|
|
auto *TruncC1 = ConstantExpr::getTrunc(C1, X->getType());
|
|
Value *BinOp;
|
|
Value *Op0LHS = Op0I->getOperand(0);
|
|
if (isa<ZExtInst>(Op0LHS))
|
|
BinOp = Builder.CreateBinOp(Op0I->getOpcode(), X, TruncC1);
|
|
else
|
|
BinOp = Builder.CreateBinOp(Op0I->getOpcode(), TruncC1, X);
|
|
auto *TruncC2 = ConstantExpr::getTrunc(AndRHS, X->getType());
|
|
auto *And = Builder.CreateAnd(BinOp, TruncC2);
|
|
return new ZExtInst(And, I.getType());
|
|
}
|
|
}
|
|
}
|
|
|
|
if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1)))
|
|
if (Instruction *Res = OptAndOp(Op0I, Op0CI, AndRHS, I))
|
|
return Res;
|
|
}
|
|
|
|
// If this is an integer truncation, and if the source is an 'and' with
|
|
// immediate, transform it. This frequently occurs for bitfield accesses.
|
|
{
|
|
Value *X = nullptr; ConstantInt *YC = nullptr;
|
|
if (match(Op0, m_Trunc(m_And(m_Value(X), m_ConstantInt(YC))))) {
|
|
// Change: and (trunc (and X, YC) to T), C2
|
|
// into : and (trunc X to T), trunc(YC) & C2
|
|
// This will fold the two constants together, which may allow
|
|
// other simplifications.
|
|
Value *NewCast = Builder.CreateTrunc(X, I.getType(), "and.shrunk");
|
|
Constant *C3 = ConstantExpr::getTrunc(YC, I.getType());
|
|
C3 = ConstantExpr::getAnd(C3, AndRHS);
|
|
return BinaryOperator::CreateAnd(NewCast, C3);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (Instruction *Z = narrowMaskedBinOp(I))
|
|
return Z;
|
|
|
|
if (Instruction *FoldedLogic = foldBinOpIntoSelectOrPhi(I))
|
|
return FoldedLogic;
|
|
|
|
if (Instruction *DeMorgan = matchDeMorgansLaws(I, Builder))
|
|
return DeMorgan;
|
|
|
|
{
|
|
Value *A, *B, *C;
|
|
// A & (A ^ B) --> A & ~B
|
|
if (match(Op1, m_OneUse(m_c_Xor(m_Specific(Op0), m_Value(B)))))
|
|
return BinaryOperator::CreateAnd(Op0, Builder.CreateNot(B));
|
|
// (A ^ B) & A --> A & ~B
|
|
if (match(Op0, m_OneUse(m_c_Xor(m_Specific(Op1), m_Value(B)))))
|
|
return BinaryOperator::CreateAnd(Op1, Builder.CreateNot(B));
|
|
|
|
// (A ^ B) & ((B ^ C) ^ A) -> (A ^ B) & ~C
|
|
if (match(Op0, m_Xor(m_Value(A), m_Value(B))))
|
|
if (match(Op1, m_Xor(m_Xor(m_Specific(B), m_Value(C)), m_Specific(A))))
|
|
if (Op1->hasOneUse() || IsFreeToInvert(C, C->hasOneUse()))
|
|
return BinaryOperator::CreateAnd(Op0, Builder.CreateNot(C));
|
|
|
|
// ((A ^ C) ^ B) & (B ^ A) -> (B ^ A) & ~C
|
|
if (match(Op0, m_Xor(m_Xor(m_Value(A), m_Value(C)), m_Value(B))))
|
|
if (match(Op1, m_Xor(m_Specific(B), m_Specific(A))))
|
|
if (Op0->hasOneUse() || IsFreeToInvert(C, C->hasOneUse()))
|
|
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);
|
|
}
|
|
|
|
{
|
|
ICmpInst *LHS = dyn_cast<ICmpInst>(Op0);
|
|
ICmpInst *RHS = dyn_cast<ICmpInst>(Op1);
|
|
if (LHS && RHS)
|
|
if (Value *Res = foldAndOfICmps(LHS, RHS, I))
|
|
return replaceInstUsesWith(I, Res);
|
|
|
|
// TODO: Make this recursive; it's a little tricky because an arbitrary
|
|
// number of 'and' instructions might have to be created.
|
|
Value *X, *Y;
|
|
if (LHS && match(Op1, m_OneUse(m_And(m_Value(X), m_Value(Y))))) {
|
|
if (auto *Cmp = dyn_cast<ICmpInst>(X))
|
|
if (Value *Res = foldAndOfICmps(LHS, Cmp, I))
|
|
return replaceInstUsesWith(I, Builder.CreateAnd(Res, Y));
|
|
if (auto *Cmp = dyn_cast<ICmpInst>(Y))
|
|
if (Value *Res = foldAndOfICmps(LHS, Cmp, I))
|
|
return replaceInstUsesWith(I, Builder.CreateAnd(Res, X));
|
|
}
|
|
if (RHS && match(Op0, m_OneUse(m_And(m_Value(X), m_Value(Y))))) {
|
|
if (auto *Cmp = dyn_cast<ICmpInst>(X))
|
|
if (Value *Res = foldAndOfICmps(Cmp, RHS, I))
|
|
return replaceInstUsesWith(I, Builder.CreateAnd(Res, Y));
|
|
if (auto *Cmp = dyn_cast<ICmpInst>(Y))
|
|
if (Value *Res = foldAndOfICmps(Cmp, RHS, I))
|
|
return replaceInstUsesWith(I, Builder.CreateAnd(Res, X));
|
|
}
|
|
}
|
|
|
|
if (FCmpInst *LHS = dyn_cast<FCmpInst>(I.getOperand(0)))
|
|
if (FCmpInst *RHS = dyn_cast<FCmpInst>(I.getOperand(1)))
|
|
if (Value *Res = foldLogicOfFCmps(LHS, RHS, true))
|
|
return replaceInstUsesWith(I, Res);
|
|
|
|
if (Instruction *CastedAnd = foldCastedBitwiseLogic(I))
|
|
return CastedAnd;
|
|
|
|
// and(sext(A), B) / and(B, sext(A)) --> A ? B : 0, where A is i1 or <N x i1>.
|
|
Value *A;
|
|
if (match(Op0, m_OneUse(m_SExt(m_Value(A)))) &&
|
|
A->getType()->isIntOrIntVectorTy(1))
|
|
return SelectInst::Create(A, Op1, Constant::getNullValue(I.getType()));
|
|
if (match(Op1, m_OneUse(m_SExt(m_Value(A)))) &&
|
|
A->getType()->isIntOrIntVectorTy(1))
|
|
return SelectInst::Create(A, Op0, Constant::getNullValue(I.getType()));
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
Instruction *InstCombiner::matchBSwap(BinaryOperator &Or) {
|
|
assert(Or.getOpcode() == Instruction::Or && "bswap requires an 'or'");
|
|
Value *Op0 = Or.getOperand(0), *Op1 = Or.getOperand(1);
|
|
|
|
// Look through zero extends.
|
|
if (Instruction *Ext = dyn_cast<ZExtInst>(Op0))
|
|
Op0 = Ext->getOperand(0);
|
|
|
|
if (Instruction *Ext = dyn_cast<ZExtInst>(Op1))
|
|
Op1 = Ext->getOperand(0);
|
|
|
|
// (A | B) | C and A | (B | C) -> bswap if possible.
|
|
bool OrOfOrs = match(Op0, m_Or(m_Value(), m_Value())) ||
|
|
match(Op1, m_Or(m_Value(), m_Value()));
|
|
|
|
// (A >> B) | (C << D) and (A << B) | (B >> C) -> bswap if possible.
|
|
bool OrOfShifts = match(Op0, m_LogicalShift(m_Value(), m_Value())) &&
|
|
match(Op1, m_LogicalShift(m_Value(), m_Value()));
|
|
|
|
// (A & B) | (C & D) -> bswap if possible.
|
|
bool OrOfAnds = match(Op0, m_And(m_Value(), m_Value())) &&
|
|
match(Op1, m_And(m_Value(), m_Value()));
|
|
|
|
// (A << B) | (C & D) -> bswap if possible.
|
|
// The bigger pattern here is ((A & C1) << C2) | ((B >> C2) & C1), which is a
|
|
// part of the bswap idiom for specific values of C1, C2 (e.g. C1 = 16711935,
|
|
// C2 = 8 for i32).
|
|
// This pattern can occur when the operands of the 'or' are not canonicalized
|
|
// for some reason (not having only one use, for example).
|
|
bool OrOfAndAndSh = (match(Op0, m_LogicalShift(m_Value(), m_Value())) &&
|
|
match(Op1, m_And(m_Value(), m_Value()))) ||
|
|
(match(Op0, m_And(m_Value(), m_Value())) &&
|
|
match(Op1, m_LogicalShift(m_Value(), m_Value())));
|
|
|
|
if (!OrOfOrs && !OrOfShifts && !OrOfAnds && !OrOfAndAndSh)
|
|
return nullptr;
|
|
|
|
SmallVector<Instruction*, 4> Insts;
|
|
if (!recognizeBSwapOrBitReverseIdiom(&Or, true, false, Insts))
|
|
return nullptr;
|
|
Instruction *LastInst = Insts.pop_back_val();
|
|
LastInst->removeFromParent();
|
|
|
|
for (auto *Inst : Insts)
|
|
Worklist.Add(Inst);
|
|
return LastInst;
|
|
}
|
|
|
|
/// If all elements of two constant vectors are 0/-1 and inverses, return true.
|
|
static bool areInverseVectorBitmasks(Constant *C1, Constant *C2) {
|
|
unsigned NumElts = C1->getType()->getVectorNumElements();
|
|
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.
|
|
Value *InstCombiner::getSelectCondition(Value *A, Value *B) {
|
|
// Step 1: 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;
|
|
|
|
// Step 2: We need 0 or all-1's bitmasks.
|
|
if (ComputeNumSignBits(A) != Ty->getScalarSizeInBits())
|
|
return nullptr;
|
|
|
|
// Step 3: If B is the 'not' value of A, we have our answer.
|
|
if (match(A, m_Not(m_Specific(B)))) {
|
|
// If these are scalars or vectors of i1, A can be used directly.
|
|
if (Ty->isIntOrIntVectorTy(1))
|
|
return A;
|
|
return Builder.CreateTrunc(A, CmpInst::makeCmpResultType(Ty));
|
|
}
|
|
|
|
// 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))
|
|
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) &&
|
|
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 & C) | (B & D). Try to simplify this
|
|
/// to "A' ? C : D", where A' is a boolean or vector of booleans.
|
|
Value *InstCombiner::matchSelectFromAndOr(Value *A, Value *C, Value *B,
|
|
Value *D) {
|
|
// 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);
|
|
B = peekThroughBitcast(B, true);
|
|
if (Value *Cond = getSelectCondition(A, B)) {
|
|
// ((bc Cond) & C) | ((bc ~Cond) & D) --> bc (select Cond, (bc C), (bc D))
|
|
// The bitcasts will either all exist or all not exist. The builder will
|
|
// not create unnecessary casts if the types already match.
|
|
Value *BitcastC = Builder.CreateBitCast(C, A->getType());
|
|
Value *BitcastD = Builder.CreateBitCast(D, A->getType());
|
|
Value *Select = Builder.CreateSelect(Cond, BitcastC, BitcastD);
|
|
return Builder.CreateBitCast(Select, OrigType);
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
/// Fold (icmp)|(icmp) if possible.
|
|
Value *InstCombiner::foldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS,
|
|
Instruction &CxtI) {
|
|
// Fold (iszero(A & K1) | iszero(A & K2)) -> (A & (K1 | K2)) != (K1 | K2)
|
|
// if K1 and K2 are a one-bit mask.
|
|
if (Value *V = foldAndOrOfICmpsOfAndWithPow2(LHS, RHS, false, CxtI))
|
|
return V;
|
|
|
|
ICmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
|
|
|
|
ConstantInt *LHSC = dyn_cast<ConstantInt>(LHS->getOperand(1));
|
|
ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS->getOperand(1));
|
|
|
|
// Fold (icmp ult/ule (A + C1), C3) | (icmp ult/ule (A + C2), C3)
|
|
// --> (icmp ult/ule ((A & ~(C1 ^ C2)) + max(C1, C2)), C3)
|
|
// The original condition actually refers to the following two ranges:
|
|
// [MAX_UINT-C1+1, MAX_UINT-C1+1+C3] and [MAX_UINT-C2+1, MAX_UINT-C2+1+C3]
|
|
// We can fold these two ranges if:
|
|
// 1) C1 and C2 is unsigned greater than C3.
|
|
// 2) The two ranges are separated.
|
|
// 3) C1 ^ C2 is one-bit mask.
|
|
// 4) LowRange1 ^ LowRange2 and HighRange1 ^ HighRange2 are one-bit mask.
|
|
// This implies all values in the two ranges differ by exactly one bit.
|
|
|
|
if ((PredL == ICmpInst::ICMP_ULT || PredL == ICmpInst::ICMP_ULE) &&
|
|
PredL == PredR && LHSC && RHSC && LHS->hasOneUse() && RHS->hasOneUse() &&
|
|
LHSC->getType() == RHSC->getType() &&
|
|
LHSC->getValue() == (RHSC->getValue())) {
|
|
|
|
Value *LAdd = LHS->getOperand(0);
|
|
Value *RAdd = RHS->getOperand(0);
|
|
|
|
Value *LAddOpnd, *RAddOpnd;
|
|
ConstantInt *LAddC, *RAddC;
|
|
if (match(LAdd, m_Add(m_Value(LAddOpnd), m_ConstantInt(LAddC))) &&
|
|
match(RAdd, m_Add(m_Value(RAddOpnd), m_ConstantInt(RAddC))) &&
|
|
LAddC->getValue().ugt(LHSC->getValue()) &&
|
|
RAddC->getValue().ugt(LHSC->getValue())) {
|
|
|
|
APInt DiffC = LAddC->getValue() ^ RAddC->getValue();
|
|
if (LAddOpnd == RAddOpnd && DiffC.isPowerOf2()) {
|
|
ConstantInt *MaxAddC = nullptr;
|
|
if (LAddC->getValue().ult(RAddC->getValue()))
|
|
MaxAddC = RAddC;
|
|
else
|
|
MaxAddC = LAddC;
|
|
|
|
APInt RRangeLow = -RAddC->getValue();
|
|
APInt RRangeHigh = RRangeLow + LHSC->getValue();
|
|
APInt LRangeLow = -LAddC->getValue();
|
|
APInt LRangeHigh = LRangeLow + LHSC->getValue();
|
|
APInt LowRangeDiff = RRangeLow ^ LRangeLow;
|
|
APInt HighRangeDiff = RRangeHigh ^ LRangeHigh;
|
|
APInt RangeDiff = LRangeLow.sgt(RRangeLow) ? LRangeLow - RRangeLow
|
|
: RRangeLow - LRangeLow;
|
|
|
|
if (LowRangeDiff.isPowerOf2() && LowRangeDiff == HighRangeDiff &&
|
|
RangeDiff.ugt(LHSC->getValue())) {
|
|
Value *MaskC = ConstantInt::get(LAddC->getType(), ~DiffC);
|
|
|
|
Value *NewAnd = Builder.CreateAnd(LAddOpnd, MaskC);
|
|
Value *NewAdd = Builder.CreateAdd(NewAnd, MaxAddC);
|
|
return Builder.CreateICmp(LHS->getPredicate(), NewAdd, LHSC);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// (icmp1 A, B) | (icmp2 A, B) --> (icmp3 A, B)
|
|
if (PredicatesFoldable(PredL, PredR)) {
|
|
if (LHS->getOperand(0) == RHS->getOperand(1) &&
|
|
LHS->getOperand(1) == RHS->getOperand(0))
|
|
LHS->swapOperands();
|
|
if (LHS->getOperand(0) == RHS->getOperand(0) &&
|
|
LHS->getOperand(1) == RHS->getOperand(1)) {
|
|
Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1);
|
|
unsigned Code = getICmpCode(LHS) | getICmpCode(RHS);
|
|
bool isSigned = LHS->isSigned() || RHS->isSigned();
|
|
return getNewICmpValue(isSigned, Code, Op0, Op1, Builder);
|
|
}
|
|
}
|
|
|
|
// handle (roughly):
|
|
// (icmp ne (A & B), C) | (icmp ne (A & D), E)
|
|
if (Value *V = foldLogOpOfMaskedICmps(LHS, RHS, false, Builder))
|
|
return V;
|
|
|
|
Value *LHS0 = LHS->getOperand(0), *RHS0 = RHS->getOperand(0);
|
|
if (LHS->hasOneUse() || RHS->hasOneUse()) {
|
|
// (icmp eq B, 0) | (icmp ult A, B) -> (icmp ule A, B-1)
|
|
// (icmp eq B, 0) | (icmp ugt B, A) -> (icmp ule A, B-1)
|
|
Value *A = nullptr, *B = nullptr;
|
|
if (PredL == ICmpInst::ICMP_EQ && LHSC && LHSC->isZero()) {
|
|
B = LHS0;
|
|
if (PredR == ICmpInst::ICMP_ULT && LHS0 == RHS->getOperand(1))
|
|
A = RHS0;
|
|
else if (PredR == ICmpInst::ICMP_UGT && LHS0 == RHS0)
|
|
A = RHS->getOperand(1);
|
|
}
|
|
// (icmp ult A, B) | (icmp eq B, 0) -> (icmp ule A, B-1)
|
|
// (icmp ugt B, A) | (icmp eq B, 0) -> (icmp ule A, B-1)
|
|
else if (PredR == ICmpInst::ICMP_EQ && RHSC && RHSC->isZero()) {
|
|
B = RHS0;
|
|
if (PredL == ICmpInst::ICMP_ULT && RHS0 == LHS->getOperand(1))
|
|
A = LHS0;
|
|
else if (PredL == ICmpInst::ICMP_UGT && LHS0 == RHS0)
|
|
A = LHS->getOperand(1);
|
|
}
|
|
if (A && B)
|
|
return Builder.CreateICmp(
|
|
ICmpInst::ICMP_UGE,
|
|
Builder.CreateAdd(B, ConstantInt::getSigned(B->getType(), -1)), A);
|
|
}
|
|
|
|
// E.g. (icmp slt x, 0) | (icmp sgt x, n) --> icmp ugt x, n
|
|
if (Value *V = simplifyRangeCheck(LHS, RHS, /*Inverted=*/true))
|
|
return V;
|
|
|
|
// E.g. (icmp sgt x, n) | (icmp slt x, 0) --> icmp ugt x, n
|
|
if (Value *V = simplifyRangeCheck(RHS, LHS, /*Inverted=*/true))
|
|
return V;
|
|
|
|
if (Value *V = foldAndOrOfEqualityCmpsWithConstants(LHS, RHS, false, Builder))
|
|
return V;
|
|
|
|
// This only handles icmp of constants: (icmp1 A, C1) | (icmp2 B, C2).
|
|
if (!LHSC || !RHSC)
|
|
return nullptr;
|
|
|
|
if (LHSC == RHSC && PredL == PredR) {
|
|
// (icmp ne A, 0) | (icmp ne B, 0) --> (icmp ne (A|B), 0)
|
|
if (PredL == ICmpInst::ICMP_NE && LHSC->isZero()) {
|
|
Value *NewOr = Builder.CreateOr(LHS0, RHS0);
|
|
return Builder.CreateICmp(PredL, NewOr, LHSC);
|
|
}
|
|
}
|
|
|
|
// (icmp ult (X + CA), C1) | (icmp eq X, C2) -> (icmp ule (X + CA), C1)
|
|
// iff C2 + CA == C1.
|
|
if (PredL == ICmpInst::ICMP_ULT && PredR == ICmpInst::ICMP_EQ) {
|
|
ConstantInt *AddC;
|
|
if (match(LHS0, m_Add(m_Specific(RHS0), m_ConstantInt(AddC))))
|
|
if (RHSC->getValue() + AddC->getValue() == LHSC->getValue())
|
|
return Builder.CreateICmpULE(LHS0, LHSC);
|
|
}
|
|
|
|
// From here on, we only handle:
|
|
// (icmp1 A, C1) | (icmp2 A, C2) --> something simpler.
|
|
if (LHS0 != RHS0)
|
|
return nullptr;
|
|
|
|
// ICMP_[US][GL]E X, C is folded to ICMP_[US][GL]T elsewhere.
|
|
if (PredL == ICmpInst::ICMP_UGE || PredL == ICmpInst::ICMP_ULE ||
|
|
PredR == ICmpInst::ICMP_UGE || PredR == ICmpInst::ICMP_ULE ||
|
|
PredL == ICmpInst::ICMP_SGE || PredL == ICmpInst::ICMP_SLE ||
|
|
PredR == ICmpInst::ICMP_SGE || PredR == ICmpInst::ICMP_SLE)
|
|
return nullptr;
|
|
|
|
// We can't fold (ugt x, C) | (sgt x, C2).
|
|
if (!PredicatesFoldable(PredL, PredR))
|
|
return nullptr;
|
|
|
|
// Ensure that the larger constant is on the RHS.
|
|
bool ShouldSwap;
|
|
if (CmpInst::isSigned(PredL) ||
|
|
(ICmpInst::isEquality(PredL) && CmpInst::isSigned(PredR)))
|
|
ShouldSwap = LHSC->getValue().sgt(RHSC->getValue());
|
|
else
|
|
ShouldSwap = LHSC->getValue().ugt(RHSC->getValue());
|
|
|
|
if (ShouldSwap) {
|
|
std::swap(LHS, RHS);
|
|
std::swap(LHSC, RHSC);
|
|
std::swap(PredL, PredR);
|
|
}
|
|
|
|
// At this point, we know we have two icmp instructions
|
|
// comparing a value against two constants and or'ing the result
|
|
// together. Because of the above check, we know that we only have
|
|
// ICMP_EQ, ICMP_NE, ICMP_LT, and ICMP_GT here. We also know (from the
|
|
// icmp folding check above), that the two constants are not
|
|
// equal.
|
|
assert(LHSC != RHSC && "Compares not folded above?");
|
|
|
|
switch (PredL) {
|
|
default:
|
|
llvm_unreachable("Unknown integer condition code!");
|
|
case ICmpInst::ICMP_EQ:
|
|
switch (PredR) {
|
|
default:
|
|
llvm_unreachable("Unknown integer condition code!");
|
|
case ICmpInst::ICMP_EQ:
|
|
// Potential folds for this case should already be handled.
|
|
break;
|
|
case ICmpInst::ICMP_UGT: // (X == 13 | X u> 14) -> no change
|
|
case ICmpInst::ICMP_SGT: // (X == 13 | X s> 14) -> no change
|
|
break;
|
|
}
|
|
break;
|
|
case ICmpInst::ICMP_ULT:
|
|
switch (PredR) {
|
|
default:
|
|
llvm_unreachable("Unknown integer condition code!");
|
|
case ICmpInst::ICMP_EQ: // (X u< 13 | X == 14) -> no change
|
|
break;
|
|
case ICmpInst::ICMP_UGT: // (X u< 13 | X u> 15) -> (X-13) u> 2
|
|
assert(!RHSC->isMaxValue(false) && "Missed icmp simplification");
|
|
return insertRangeTest(LHS0, LHSC->getValue(), RHSC->getValue() + 1,
|
|
false, false);
|
|
}
|
|
break;
|
|
case ICmpInst::ICMP_SLT:
|
|
switch (PredR) {
|
|
default:
|
|
llvm_unreachable("Unknown integer condition code!");
|
|
case ICmpInst::ICMP_EQ: // (X s< 13 | X == 14) -> no change
|
|
break;
|
|
case ICmpInst::ICMP_SGT: // (X s< 13 | X s> 15) -> (X-13) s> 2
|
|
assert(!RHSC->isMaxValue(true) && "Missed icmp simplification");
|
|
return insertRangeTest(LHS0, LHSC->getValue(), RHSC->getValue() + 1, true,
|
|
false);
|
|
}
|
|
break;
|
|
}
|
|
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 *InstCombiner::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;
|
|
|
|
// 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;
|
|
|
|
// (A&B)|(A&C) -> A&(B|C) etc
|
|
if (Value *V = SimplifyUsingDistributiveLaws(I))
|
|
return replaceInstUsesWith(I, V);
|
|
|
|
if (Value *V = SimplifyBSwap(I, Builder))
|
|
return replaceInstUsesWith(I, V);
|
|
|
|
if (Instruction *FoldedLogic = foldBinOpIntoSelectOrPhi(I))
|
|
return FoldedLogic;
|
|
|
|
if (Instruction *BSwap = matchBSwap(I))
|
|
return BSwap;
|
|
|
|
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->isAllOnesValue() && 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(I.getType(), *CV));
|
|
}
|
|
|
|
// (A & C)|(B & D)
|
|
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
|
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)))) {
|
|
ConstantInt *C1 = dyn_cast<ConstantInt>(C);
|
|
ConstantInt *C2 = dyn_cast<ConstantInt>(D);
|
|
if (C1 && C2) { // (A & C1)|(B & C2)
|
|
Value *V1 = nullptr, *V2 = nullptr;
|
|
if ((C1->getValue() & C2->getValue()).isNullValue()) {
|
|
// ((V | N) & C1) | (V & C2) --> (V|N) & (C1|C2)
|
|
// iff (C1&C2) == 0 and (N&~C1) == 0
|
|
if (match(A, m_Or(m_Value(V1), m_Value(V2))) &&
|
|
((V1 == B &&
|
|
MaskedValueIsZero(V2, ~C1->getValue(), 0, &I)) || // (V|N)
|
|
(V2 == B &&
|
|
MaskedValueIsZero(V1, ~C1->getValue(), 0, &I)))) // (N|V)
|
|
return BinaryOperator::CreateAnd(A,
|
|
Builder.getInt(C1->getValue()|C2->getValue()));
|
|
// Or commutes, try both ways.
|
|
if (match(B, m_Or(m_Value(V1), m_Value(V2))) &&
|
|
((V1 == A &&
|
|
MaskedValueIsZero(V2, ~C2->getValue(), 0, &I)) || // (V|N)
|
|
(V2 == A &&
|
|
MaskedValueIsZero(V1, ~C2->getValue(), 0, &I)))) // (N|V)
|
|
return BinaryOperator::CreateAnd(B,
|
|
Builder.getInt(C1->getValue()|C2->getValue()));
|
|
|
|
// ((V|C3)&C1) | ((V|C4)&C2) --> (V|C3|C4)&(C1|C2)
|
|
// iff (C1&C2) == 0 and (C3&~C1) == 0 and (C4&~C2) == 0.
|
|
ConstantInt *C3 = nullptr, *C4 = nullptr;
|
|
if (match(A, m_Or(m_Value(V1), m_ConstantInt(C3))) &&
|
|
(C3->getValue() & ~C1->getValue()).isNullValue() &&
|
|
match(B, m_Or(m_Specific(V1), m_ConstantInt(C4))) &&
|
|
(C4->getValue() & ~C2->getValue()).isNullValue()) {
|
|
V2 = Builder.CreateOr(V1, ConstantExpr::getOr(C3, C4), "bitfield");
|
|
return BinaryOperator::CreateAnd(V2,
|
|
Builder.getInt(C1->getValue()|C2->getValue()));
|
|
}
|
|
}
|
|
|
|
if (C1->getValue() == ~C2->getValue()) {
|
|
Value *X;
|
|
|
|
// ((X|B)&C1)|(B&C2) -> (X&C1) | B iff C1 == ~C2
|
|
if (match(A, m_c_Or(m_Value(X), m_Specific(B))))
|
|
return BinaryOperator::CreateOr(Builder.CreateAnd(X, C1), B);
|
|
// (A&C2)|((X|A)&C1) -> (X&C2) | A iff C1 == ~C2
|
|
if (match(B, m_c_Or(m_Specific(A), m_Value(X))))
|
|
return BinaryOperator::CreateOr(Builder.CreateAnd(X, C2), A);
|
|
|
|
// ((X^B)&C1)|(B&C2) -> (X&C1) ^ B iff C1 == ~C2
|
|
if (match(A, m_c_Xor(m_Value(X), m_Specific(B))))
|
|
return BinaryOperator::CreateXor(Builder.CreateAnd(X, C1), B);
|
|
// (A&C2)|((X^A)&C1) -> (X&C2) ^ A iff C1 == ~C2
|
|
if (match(B, m_c_Xor(m_Specific(A), m_Value(X))))
|
|
return BinaryOperator::CreateXor(Builder.CreateAnd(X, C2), A);
|
|
}
|
|
}
|
|
|
|
// 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);
|
|
}
|
|
}
|
|
|
|
// (A ^ B) | ((B ^ C) ^ A) -> (A ^ B) | C
|
|
if (match(Op0, m_Xor(m_Value(A), m_Value(B))))
|
|
if (match(Op1, m_Xor(m_Xor(m_Specific(B), m_Value(C)), m_Specific(A))))
|
|
return BinaryOperator::CreateOr(Op0, C);
|
|
|
|
// ((A ^ C) ^ B) | (B ^ A) -> (B ^ A) | C
|
|
if (match(Op0, m_Xor(m_Xor(m_Value(A), m_Value(C)), m_Value(B))))
|
|
if (match(Op1, m_Xor(m_Specific(B), m_Specific(A))))
|
|
return BinaryOperator::CreateOr(Op1, C);
|
|
|
|
// ((B | C) & A) | B -> B | (A & C)
|
|
if (match(Op0, m_And(m_Or(m_Specific(Op1), m_Value(C)), m_Value(A))))
|
|
return BinaryOperator::CreateOr(Op1, Builder.CreateAnd(A, C));
|
|
|
|
if (Instruction *DeMorgan = matchDeMorgansLaws(I, Builder))
|
|
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;
|
|
}
|
|
|
|
// A | ( A ^ B) -> A | B
|
|
// A | (~A ^ B) -> A | ~B
|
|
// (A & B) | (A ^ B)
|
|
if (match(Op1, m_Xor(m_Value(A), m_Value(B)))) {
|
|
if (Op0 == A || Op0 == B)
|
|
return BinaryOperator::CreateOr(A, B);
|
|
|
|
if (match(Op0, m_And(m_Specific(A), m_Specific(B))) ||
|
|
match(Op0, m_And(m_Specific(B), m_Specific(A))))
|
|
return BinaryOperator::CreateOr(A, B);
|
|
|
|
if (Op1->hasOneUse() && match(A, m_Not(m_Specific(Op0)))) {
|
|
Value *Not = Builder.CreateNot(B, B->getName() + ".not");
|
|
return BinaryOperator::CreateOr(Not, Op0);
|
|
}
|
|
if (Op1->hasOneUse() && match(B, m_Not(m_Specific(Op0)))) {
|
|
Value *Not = Builder.CreateNot(A, A->getName() + ".not");
|
|
return BinaryOperator::CreateOr(Not, Op0);
|
|
}
|
|
}
|
|
|
|
// A | ~(A | B) -> A | ~B
|
|
// A | ~(A ^ B) -> A | ~B
|
|
if (match(Op1, m_Not(m_Value(A))))
|
|
if (BinaryOperator *B = dyn_cast<BinaryOperator>(A))
|
|
if ((Op0 == B->getOperand(0) || Op0 == B->getOperand(1)) &&
|
|
Op1->hasOneUse() && (B->getOpcode() == Instruction::Or ||
|
|
B->getOpcode() == Instruction::Xor)) {
|
|
Value *NotOp = Op0 == B->getOperand(0) ? B->getOperand(1) :
|
|
B->getOperand(0);
|
|
Value *Not = Builder.CreateNot(NotOp, NotOp->getName() + ".not");
|
|
return BinaryOperator::CreateOr(Not, Op0);
|
|
}
|
|
|
|
if (SwappedForXor)
|
|
std::swap(Op0, Op1);
|
|
|
|
{
|
|
ICmpInst *LHS = dyn_cast<ICmpInst>(Op0);
|
|
ICmpInst *RHS = dyn_cast<ICmpInst>(Op1);
|
|
if (LHS && RHS)
|
|
if (Value *Res = foldOrOfICmps(LHS, RHS, I))
|
|
return replaceInstUsesWith(I, Res);
|
|
|
|
// TODO: Make this recursive; it's a little tricky because an arbitrary
|
|
// number of 'or' instructions might have to be created.
|
|
Value *X, *Y;
|
|
if (LHS && match(Op1, m_OneUse(m_Or(m_Value(X), m_Value(Y))))) {
|
|
if (auto *Cmp = dyn_cast<ICmpInst>(X))
|
|
if (Value *Res = foldOrOfICmps(LHS, Cmp, I))
|
|
return replaceInstUsesWith(I, Builder.CreateOr(Res, Y));
|
|
if (auto *Cmp = dyn_cast<ICmpInst>(Y))
|
|
if (Value *Res = foldOrOfICmps(LHS, Cmp, I))
|
|
return replaceInstUsesWith(I, Builder.CreateOr(Res, X));
|
|
}
|
|
if (RHS && match(Op0, m_OneUse(m_Or(m_Value(X), m_Value(Y))))) {
|
|
if (auto *Cmp = dyn_cast<ICmpInst>(X))
|
|
if (Value *Res = foldOrOfICmps(Cmp, RHS, I))
|
|
return replaceInstUsesWith(I, Builder.CreateOr(Res, Y));
|
|
if (auto *Cmp = dyn_cast<ICmpInst>(Y))
|
|
if (Value *Res = foldOrOfICmps(Cmp, RHS, I))
|
|
return replaceInstUsesWith(I, Builder.CreateOr(Res, X));
|
|
}
|
|
}
|
|
|
|
if (FCmpInst *LHS = dyn_cast<FCmpInst>(I.getOperand(0)))
|
|
if (FCmpInst *RHS = dyn_cast<FCmpInst>(I.getOperand(1)))
|
|
if (Value *Res = foldLogicOfFCmps(LHS, RHS, false))
|
|
return replaceInstUsesWith(I, Res);
|
|
|
|
if (Instruction *CastedOr = foldCastedBitwiseLogic(I))
|
|
return CastedOr;
|
|
|
|
// or(sext(A), B) / or(B, sext(A)) --> A ? -1 : B, where A is i1 or <N x i1>.
|
|
if (match(Op0, m_OneUse(m_SExt(m_Value(A)))) &&
|
|
A->getType()->isIntOrIntVectorTy(1))
|
|
return SelectInst::Create(A, ConstantInt::getSigned(I.getType(), -1), Op1);
|
|
if (match(Op1, m_OneUse(m_SExt(m_Value(A)))) &&
|
|
A->getType()->isIntOrIntVectorTy(1))
|
|
return SelectInst::Create(A, ConstantInt::getSigned(I.getType(), -1), Op0);
|
|
|
|
// 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() && !isa<ConstantInt>(Op1) &&
|
|
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);
|
|
}
|
|
}
|
|
|
|
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))))) {
|
|
I.setOperand(0, A);
|
|
I.setOperand(1, B);
|
|
return &I;
|
|
}
|
|
|
|
// (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))))) {
|
|
I.setOperand(0, A);
|
|
I.setOperand(1, B);
|
|
return &I;
|
|
}
|
|
|
|
// (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))))) {
|
|
I.setOperand(0, A);
|
|
I.setOperand(1, B);
|
|
return &I;
|
|
}
|
|
|
|
// 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 *InstCombiner::foldXorOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
|
|
if (PredicatesFoldable(LHS->getPredicate(), RHS->getPredicate())) {
|
|
if (LHS->getOperand(0) == RHS->getOperand(1) &&
|
|
LHS->getOperand(1) == RHS->getOperand(0))
|
|
LHS->swapOperands();
|
|
if (LHS->getOperand(0) == RHS->getOperand(0) &&
|
|
LHS->getOperand(1) == RHS->getOperand(1)) {
|
|
// (icmp1 A, B) ^ (icmp2 A, B) --> (icmp3 A, B)
|
|
Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1);
|
|
unsigned Code = getICmpCode(LHS) ^ getICmpCode(RHS);
|
|
bool isSigned = LHS->isSigned() || RHS->isSigned();
|
|
return getNewICmpValue(isSigned, Code, Op0, Op1, Builder);
|
|
}
|
|
}
|
|
|
|
// TODO: This can be generalized to compares of non-signbits using
|
|
// decomposeBitTestICmp(). It could be enhanced more by using (something like)
|
|
// foldLogOpOfMaskedICmps().
|
|
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 ((LHS->hasOneUse() || RHS->hasOneUse()) &&
|
|
LHS0->getType() == RHS0->getType() &&
|
|
LHS0->getType()->isIntOrIntVectorTy()) {
|
|
// (X > -1) ^ (Y > -1) --> (X ^ Y) < 0
|
|
// (X < 0) ^ (Y < 0) --> (X ^ Y) < 0
|
|
if ((PredL == CmpInst::ICMP_SGT && match(LHS1, m_AllOnes()) &&
|
|
PredR == CmpInst::ICMP_SGT && match(RHS1, m_AllOnes())) ||
|
|
(PredL == CmpInst::ICMP_SLT && match(LHS1, m_Zero()) &&
|
|
PredR == CmpInst::ICMP_SLT && match(RHS1, m_Zero()))) {
|
|
Value *Zero = ConstantInt::getNullValue(LHS0->getType());
|
|
return Builder.CreateICmpSLT(Builder.CreateXor(LHS0, RHS0), Zero);
|
|
}
|
|
// (X > -1) ^ (Y < 0) --> (X ^ Y) > -1
|
|
// (X < 0) ^ (Y > -1) --> (X ^ Y) > -1
|
|
if ((PredL == CmpInst::ICMP_SGT && match(LHS1, m_AllOnes()) &&
|
|
PredR == CmpInst::ICMP_SLT && match(RHS1, m_Zero())) ||
|
|
(PredL == CmpInst::ICMP_SLT && match(LHS1, m_Zero()) &&
|
|
PredR == CmpInst::ICMP_SGT && match(RHS1, m_AllOnes()))) {
|
|
Value *MinusOne = ConstantInt::getAllOnesValue(LHS0->getType());
|
|
return Builder.CreateICmpSGT(Builder.CreateXor(LHS0, RHS0), MinusOne);
|
|
}
|
|
}
|
|
|
|
// 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.
|
|
if (OrICmp == LHS && AndICmp == RHS && RHS->hasOneUse()) {
|
|
// (LHS | RHS) & !(LHS & RHS) --> LHS & !RHS
|
|
RHS->setPredicate(RHS->getInversePredicate());
|
|
return Builder.CreateAnd(LHS, RHS);
|
|
}
|
|
if (OrICmp == RHS && AndICmp == LHS && LHS->hasOneUse()) {
|
|
// !(LHS & RHS) & (LHS | RHS) --> !LHS & RHS
|
|
LHS->setPredicate(LHS->getInversePredicate());
|
|
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))) {
|
|
// 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;
|
|
}
|
|
|
|
// Transform
|
|
// ~(x ^ y)
|
|
// into:
|
|
// (~x) ^ y
|
|
// or into
|
|
// x ^ (~y)
|
|
static Instruction *sinkNotIntoXor(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;
|
|
|
|
// We only want to do the transform if it is free to do.
|
|
if (IsFreeToInvert(X, X->hasOneUse())) {
|
|
// Ok, good.
|
|
} else if (IsFreeToInvert(Y, Y->hasOneUse())) {
|
|
std::swap(X, Y);
|
|
} else
|
|
return nullptr;
|
|
|
|
Value *NotX = Builder.CreateNot(X, X->getName() + ".not");
|
|
return BinaryOperator::CreateXor(NotX, Y, I.getName() + ".demorgan");
|
|
}
|
|
|
|
// 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 *InstCombiner::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 *NewXor = foldXorToXor(I, Builder))
|
|
return NewXor;
|
|
|
|
// (A&B)^(A&C) -> A&(B^C) etc
|
|
if (Value *V = SimplifyUsingDistributiveLaws(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 (Value *V = SimplifyBSwap(I, Builder))
|
|
return replaceInstUsesWith(I, V);
|
|
|
|
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
|
|
|
// 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.
|
|
Value *M;
|
|
if (match(&I, m_c_Xor(m_c_And(m_Not(m_Value(M)), m_Value()),
|
|
m_c_And(m_Deferred(M), m_Value()))))
|
|
return BinaryOperator::CreateOr(Op0, Op1);
|
|
|
|
// Apply DeMorgan's Law for 'nand' / 'nor' logic with an inverted operand.
|
|
Value *X, *Y;
|
|
|
|
// 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)
|
|
if (match(&I, m_Not(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);
|
|
}
|
|
// ~(~X | Y) --> (X & ~Y)
|
|
// ~(Y | ~X) --> (X & ~Y)
|
|
if (match(&I, m_Not(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 (Instruction *Xor = visitMaskedMerge(I, Builder))
|
|
return Xor;
|
|
|
|
// Is this a 'not' (~) fed by a binary operator?
|
|
BinaryOperator *NotVal;
|
|
if (match(&I, m_Not(m_BinOp(NotVal)))) {
|
|
if (NotVal->getOpcode() == Instruction::And ||
|
|
NotVal->getOpcode() == Instruction::Or) {
|
|
// Apply DeMorgan's Law when inverts are free:
|
|
// ~(X & Y) --> (~X | ~Y)
|
|
// ~(X | Y) --> (~X & ~Y)
|
|
if (IsFreeToInvert(NotVal->getOperand(0),
|
|
NotVal->getOperand(0)->hasOneUse()) &&
|
|
IsFreeToInvert(NotVal->getOperand(1),
|
|
NotVal->getOperand(1)->hasOneUse())) {
|
|
Value *NotX = Builder.CreateNot(NotVal->getOperand(0), "notlhs");
|
|
Value *NotY = Builder.CreateNot(NotVal->getOperand(1), "notrhs");
|
|
if (NotVal->getOpcode() == Instruction::And)
|
|
return BinaryOperator::CreateOr(NotX, NotY);
|
|
return BinaryOperator::CreateAnd(NotX, NotY);
|
|
}
|
|
}
|
|
|
|
// ~(X - Y) --> ~X + Y
|
|
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 >>s Y) --> (X >>s Y)
|
|
if (match(NotVal, m_AShr(m_Not(m_Value(X)), m_Value(Y))))
|
|
return BinaryOperator::CreateAShr(X, Y);
|
|
|
|
// 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 + 1) - X
|
|
if (match(Op0, m_Add(m_Value(X), m_Constant(C))))
|
|
return BinaryOperator::CreateSub(ConstantExpr::getNeg(AddOne(C)), X);
|
|
}
|
|
|
|
// Use DeMorgan and reassociation to eliminate a 'not' op.
|
|
Constant *C1;
|
|
if (match(Op1, m_Constant(C1))) {
|
|
Constant *C2;
|
|
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));
|
|
}
|
|
}
|
|
|
|
// not (cmp A, B) = !cmp A, B
|
|
CmpInst::Predicate Pred;
|
|
if (match(&I, m_Not(m_OneUse(m_Cmp(Pred, m_Value(), m_Value()))))) {
|
|
cast<CmpInst>(Op0)->setPredicate(CmpInst::getInversePredicate(Pred));
|
|
return replaceInstUsesWith(I, Op0);
|
|
}
|
|
|
|
{
|
|
const APInt *RHSC;
|
|
if (match(Op1, m_APInt(RHSC))) {
|
|
Value *X;
|
|
const APInt *C;
|
|
if (RHSC->isSignMask() && match(Op0, m_Sub(m_APInt(C), m_Value(X)))) {
|
|
// (C - X) ^ signmask -> (C + signmask - X)
|
|
Constant *NewC = ConstantInt::get(I.getType(), *C + *RHSC);
|
|
return BinaryOperator::CreateSub(NewC, X);
|
|
}
|
|
if (RHSC->isSignMask() && match(Op0, m_Add(m_Value(X), m_APInt(C)))) {
|
|
// (X + C) ^ signmask -> (X + C + signmask)
|
|
Constant *NewC = ConstantInt::get(I.getType(), *C + *RHSC);
|
|
return BinaryOperator::CreateAdd(X, NewC);
|
|
}
|
|
|
|
// (X|C1)^C2 -> X^(C1^C2) iff X&~C1 == 0
|
|
if (match(Op0, m_Or(m_Value(X), m_APInt(C))) &&
|
|
MaskedValueIsZero(X, *C, 0, &I)) {
|
|
Constant *NewC = ConstantInt::get(I.getType(), *C ^ *RHSC);
|
|
Worklist.Add(cast<Instruction>(Op0));
|
|
I.setOperand(0, X);
|
|
I.setOperand(1, NewC);
|
|
return &I;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (ConstantInt *RHSC = dyn_cast<ConstantInt>(Op1)) {
|
|
if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
|
|
if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) {
|
|
if (Op0I->getOpcode() == Instruction::LShr) {
|
|
// ((X^C1) >> C2) ^ C3 -> (X>>C2) ^ ((C1>>C2)^C3)
|
|
// E1 = "X ^ C1"
|
|
BinaryOperator *E1;
|
|
ConstantInt *C1;
|
|
if (Op0I->hasOneUse() &&
|
|
(E1 = dyn_cast<BinaryOperator>(Op0I->getOperand(0))) &&
|
|
E1->getOpcode() == Instruction::Xor &&
|
|
(C1 = dyn_cast<ConstantInt>(E1->getOperand(1)))) {
|
|
// fold (C1 >> C2) ^ C3
|
|
ConstantInt *C2 = Op0CI, *C3 = RHSC;
|
|
APInt FoldConst = C1->getValue().lshr(C2->getValue());
|
|
FoldConst ^= C3->getValue();
|
|
// Prepare the two operands.
|
|
Value *Opnd0 = Builder.CreateLShr(E1->getOperand(0), C2);
|
|
Opnd0->takeName(Op0I);
|
|
cast<Instruction>(Opnd0)->setDebugLoc(I.getDebugLoc());
|
|
Value *FoldVal = ConstantInt::get(Opnd0->getType(), FoldConst);
|
|
|
|
return BinaryOperator::CreateXor(Opnd0, FoldVal);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
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));
|
|
|
|
if (auto *LHS = dyn_cast<ICmpInst>(I.getOperand(0)))
|
|
if (auto *RHS = dyn_cast<ICmpInst>(I.getOperand(1)))
|
|
if (Value *V = foldXorOfICmps(LHS, RHS))
|
|
return replaceInstUsesWith(I, V);
|
|
|
|
if (Instruction *CastedXor = foldCastedBitwiseLogic(I))
|
|
return CastedXor;
|
|
|
|
// Canonicalize a shifty way to code absolute value to the common pattern.
|
|
// 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).
|
|
if (Op0->hasNUses(2))
|
|
std::swap(Op0, Op1);
|
|
|
|
const APInt *ShAmt;
|
|
Type *Ty = I.getType();
|
|
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))))) {
|
|
// B = ashr i32 A, 31 ; smear the sign bit
|
|
// xor (add A, B), B ; add -1 and flip bits if negative
|
|
// --> (A < 0) ? -A : A
|
|
Value *Cmp = Builder.CreateICmpSLT(A, ConstantInt::getNullValue(Ty));
|
|
// Copy the nuw/nsw flags from the add to the negate.
|
|
auto *Add = cast<BinaryOperator>(Op0);
|
|
Value *Neg = Builder.CreateNeg(A, "", Add->hasNoUnsignedWrap(),
|
|
Add->hasNoSignedWrap());
|
|
return SelectInst::Create(Cmp, Neg, A);
|
|
}
|
|
|
|
// Eliminate a bitwise 'not' op of 'not' min/max by inverting the min/max:
|
|
//
|
|
// %notx = xor i32 %x, -1
|
|
// %cmp1 = icmp sgt i32 %notx, %y
|
|
// %smax = select i1 %cmp1, i32 %notx, i32 %y
|
|
// %res = xor i32 %smax, -1
|
|
// =>
|
|
// %noty = xor i32 %y, -1
|
|
// %cmp2 = icmp slt %x, %noty
|
|
// %res = select i1 %cmp2, i32 %x, i32 %noty
|
|
//
|
|
// Same is applicable for smin/umax/umin.
|
|
if (match(Op1, m_AllOnes()) && Op0->hasOneUse()) {
|
|
Value *LHS, *RHS;
|
|
SelectPatternFlavor SPF = matchSelectPattern(Op0, LHS, RHS).Flavor;
|
|
if (SelectPatternResult::isMinOrMax(SPF)) {
|
|
// It's possible we get here before the not has been simplified, so make
|
|
// sure the input to the not isn't freely invertible.
|
|
if (match(LHS, m_Not(m_Value(X))) && !IsFreeToInvert(X, X->hasOneUse())) {
|
|
Value *NotY = Builder.CreateNot(RHS);
|
|
return SelectInst::Create(
|
|
Builder.CreateICmp(getInverseMinMaxPred(SPF), X, NotY), X, NotY);
|
|
}
|
|
|
|
// It's possible we get here before the not has been simplified, so make
|
|
// sure the input to the not isn't freely invertible.
|
|
if (match(RHS, m_Not(m_Value(Y))) && !IsFreeToInvert(Y, Y->hasOneUse())) {
|
|
Value *NotX = Builder.CreateNot(LHS);
|
|
return SelectInst::Create(
|
|
Builder.CreateICmp(getInverseMinMaxPred(SPF), NotX, Y), NotX, Y);
|
|
}
|
|
|
|
// If both sides are freely invertible, then we can get rid of the xor
|
|
// completely.
|
|
if (IsFreeToInvert(LHS, !LHS->hasNUsesOrMore(3)) &&
|
|
IsFreeToInvert(RHS, !RHS->hasNUsesOrMore(3))) {
|
|
Value *NotLHS = Builder.CreateNot(LHS);
|
|
Value *NotRHS = Builder.CreateNot(RHS);
|
|
return SelectInst::Create(
|
|
Builder.CreateICmp(getInverseMinMaxPred(SPF), NotLHS, NotRHS),
|
|
NotLHS, NotRHS);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (Instruction *NewXor = sinkNotIntoXor(I, Builder))
|
|
return NewXor;
|
|
|
|
return nullptr;
|
|
}
|