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[InstCombine] various clean-ups for div transforms; NFC

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llvm-svn: 324922
This commit is contained in:
Sanjay Patel 2018-02-12 18:38:35 +00:00
parent 1f9742c135
commit 067d5132f3
1 changed files with 100 additions and 114 deletions
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214
lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
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@ -95,41 +95,6 @@ static Value *simplifyValueKnownNonZero(Value *V, InstCombiner &IC,
return MadeChange ? V : nullptr;
}
/// True if the multiply can not be expressed in an int this size.
static bool MultiplyOverflows(const APInt &C1, const APInt &C2, APInt &Product,
bool IsSigned) {
bool Overflow;
if (IsSigned)
Product = C1.smul_ov(C2, Overflow);
else
Product = C1.umul_ov(C2, Overflow);
return Overflow;
}
/// \brief True if C2 is a multiple of C1. Quotient contains C2/C1.
static bool IsMultiple(const APInt &C1, const APInt &C2, APInt &Quotient,
bool IsSigned) {
assert(C1.getBitWidth() == C2.getBitWidth() &&
"Inconsistent width of constants!");
// Bail if we will divide by zero.
if (C2.isMinValue())
return false;
// Bail if we would divide INT_MIN by -1.
if (IsSigned && C1.isMinSignedValue() && C2.isAllOnesValue())
return false;
APInt Remainder(C1.getBitWidth(), /*Val=*/0ULL, IsSigned);
if (IsSigned)
APInt::sdivrem(C1, C2, Quotient, Remainder);
else
APInt::udivrem(C1, C2, Quotient, Remainder);
return Remainder.isMinValue();
}
/// \brief A helper routine of InstCombiner::visitMul().
///
/// If C is a scalar/vector of known powers of 2, then this function returns
@ -734,8 +699,7 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
}
// sqrt(a) * sqrt(b) -> sqrt(a * b)
if (AllowReassociate &&
Op0->hasOneUse() && Op1->hasOneUse()) {
if (AllowReassociate && Op0->hasOneUse() && Op1->hasOneUse()) {
Value *Opnd0 = nullptr;
Value *Opnd1 = nullptr;
if (match(Op0, m_Intrinsic<Intrinsic::sqrt>(m_Value(Opnd0))) &&
@ -889,6 +853,36 @@ bool InstCombiner::simplifyDivRemOfSelectWithZeroOp(BinaryOperator &I) {
return true;
}
/// True if the multiply can not be expressed in an int this size.
static bool multiplyOverflows(const APInt &C1, const APInt &C2, APInt &Product,
bool IsSigned) {
bool Overflow;
Product = IsSigned ? C1.smul_ov(C2, Overflow) : C1.umul_ov(C2, Overflow);
return Overflow;
}
/// True if C2 is a multiple of C1. Quotient contains C2/C1.
static bool isMultiple(const APInt &C1, const APInt &C2, APInt &Quotient,
bool IsSigned) {
assert(C1.getBitWidth() == C2.getBitWidth() && "Constant widths not equal");
// Bail if we will divide by zero.
if (C2.isNullValue())
return false;
// Bail if we would divide INT_MIN by -1.
if (IsSigned && C1.isMinSignedValue() && C2.isAllOnesValue())
return false;
APInt Remainder(C1.getBitWidth(), /*Val=*/0ULL, IsSigned);
if (IsSigned)
APInt::sdivrem(C1, C2, Quotient, Remainder);
else
APInt::udivrem(C1, C2, Quotient, Remainder);
return Remainder.isMinValue();
}
/// This function implements the transforms common to both integer division
/// instructions (udiv and sdiv). It is called by the visitors to those integer
/// division instructions.
@ -909,78 +903,72 @@ Instruction *InstCombiner::commonIDivTransforms(BinaryOperator &I) {
if (simplifyDivRemOfSelectWithZeroOp(I))
return &I;
if (auto *LHS = dyn_cast<Instruction>(Op0)) {
const APInt *C2;
if (match(Op1, m_APInt(C2))) {
Value *X;
const APInt *C1;
const APInt *C2;
if (match(Op1, m_APInt(C2))) {
Value *X;
const APInt *C1;
// (X / C1) / C2 -> X / (C1*C2)
if ((IsSigned && match(LHS, m_SDiv(m_Value(X), m_APInt(C1)))) ||
(!IsSigned && match(LHS, m_UDiv(m_Value(X), m_APInt(C1))))) {
APInt Product(C1->getBitWidth(), /*Val=*/0ULL, IsSigned);
if (!MultiplyOverflows(*C1, *C2, Product, IsSigned))
return BinaryOperator::Create(I.getOpcode(), X,
ConstantInt::get(Ty, Product));
}
if ((IsSigned && match(LHS, m_NSWMul(m_Value(X), m_APInt(C1)))) ||
(!IsSigned && match(LHS, m_NUWMul(m_Value(X), m_APInt(C1))))) {
APInt Quotient(C1->getBitWidth(), /*Val=*/0ULL, IsSigned);
// (X * C1) / C2 -> X / (C2 / C1) if C2 is a multiple of C1.
if (IsMultiple(*C2, *C1, Quotient, IsSigned)) {
BinaryOperator *BO = BinaryOperator::Create(
I.getOpcode(), X, ConstantInt::get(Ty, Quotient));
BO->setIsExact(I.isExact());
return BO;
}
// (X * C1) / C2 -> X * (C1 / C2) if C1 is a multiple of C2.
if (IsMultiple(*C1, *C2, Quotient, IsSigned)) {
BinaryOperator *BO = BinaryOperator::Create(
Instruction::Mul, X, ConstantInt::get(Ty, Quotient));
BO->setHasNoUnsignedWrap(
!IsSigned &&
cast<OverflowingBinaryOperator>(LHS)->hasNoUnsignedWrap());
BO->setHasNoSignedWrap(
cast<OverflowingBinaryOperator>(LHS)->hasNoSignedWrap());
return BO;
}
}
if ((IsSigned && match(LHS, m_NSWShl(m_Value(X), m_APInt(C1))) &&
*C1 != C1->getBitWidth() - 1) ||
(!IsSigned && match(LHS, m_NUWShl(m_Value(X), m_APInt(C1))))) {
APInt Quotient(C1->getBitWidth(), /*Val=*/0ULL, IsSigned);
APInt C1Shifted = APInt::getOneBitSet(
C1->getBitWidth(), static_cast<unsigned>(C1->getLimitedValue()));
// (X << C1) / C2 -> X / (C2 >> C1) if C2 is a multiple of C1.
if (IsMultiple(*C2, C1Shifted, Quotient, IsSigned)) {
auto *BO = BinaryOperator::Create(I.getOpcode(), X,
ConstantInt::get(Ty, Quotient));
BO->setIsExact(I.isExact());
return BO;
}
// (X << C1) / C2 -> X * (C2 >> C1) if C1 is a multiple of C2.
if (IsMultiple(C1Shifted, *C2, Quotient, IsSigned)) {
auto *BO = BinaryOperator::Create(Instruction::Mul, X,
ConstantInt::get(Ty, Quotient));
BO->setHasNoUnsignedWrap(
!IsSigned &&
cast<OverflowingBinaryOperator>(LHS)->hasNoUnsignedWrap());
BO->setHasNoSignedWrap(
cast<OverflowingBinaryOperator>(LHS)->hasNoSignedWrap());
return BO;
}
}
if (!C2->isNullValue()) // avoid X udiv 0
if (Instruction *FoldedDiv = foldOpWithConstantIntoOperand(I))
return FoldedDiv;
// (X / C1) / C2 -> X / (C1*C2)
if ((IsSigned && match(Op0, m_SDiv(m_Value(X), m_APInt(C1)))) ||
(!IsSigned && match(Op0, m_UDiv(m_Value(X), m_APInt(C1))))) {
APInt Product(C1->getBitWidth(), /*Val=*/0ULL, IsSigned);
if (!multiplyOverflows(*C1, *C2, Product, IsSigned))
return BinaryOperator::Create(I.getOpcode(), X,
ConstantInt::get(Ty, Product));
}
if ((IsSigned && match(Op0, m_NSWMul(m_Value(X), m_APInt(C1)))) ||
(!IsSigned && match(Op0, m_NUWMul(m_Value(X), m_APInt(C1))))) {
APInt Quotient(C1->getBitWidth(), /*Val=*/0ULL, IsSigned);
// (X * C1) / C2 -> X / (C2 / C1) if C2 is a multiple of C1.
if (isMultiple(*C2, *C1, Quotient, IsSigned)) {
auto *NewDiv = BinaryOperator::Create(I.getOpcode(), X,
ConstantInt::get(Ty, Quotient));
NewDiv->setIsExact(I.isExact());
return NewDiv;
}
// (X * C1) / C2 -> X * (C1 / C2) if C1 is a multiple of C2.
if (isMultiple(*C1, *C2, Quotient, IsSigned)) {
auto *Mul = BinaryOperator::Create(Instruction::Mul, X,
ConstantInt::get(Ty, Quotient));
auto *OBO = cast<OverflowingBinaryOperator>(Op0);
Mul->setHasNoUnsignedWrap(!IsSigned && OBO->hasNoUnsignedWrap());
Mul->setHasNoSignedWrap(OBO->hasNoSignedWrap());
return Mul;
}
}
if ((IsSigned && match(Op0, m_NSWShl(m_Value(X), m_APInt(C1))) &&
*C1 != C1->getBitWidth() - 1) ||
(!IsSigned && match(Op0, m_NUWShl(m_Value(X), m_APInt(C1))))) {
APInt Quotient(C1->getBitWidth(), /*Val=*/0ULL, IsSigned);
APInt C1Shifted = APInt::getOneBitSet(
C1->getBitWidth(), static_cast<unsigned>(C1->getLimitedValue()));
// (X << C1) / C2 -> X / (C2 >> C1) if C2 is a multiple of C1.
if (isMultiple(*C2, C1Shifted, Quotient, IsSigned)) {
auto *BO = BinaryOperator::Create(I.getOpcode(), X,
ConstantInt::get(Ty, Quotient));
BO->setIsExact(I.isExact());
return BO;
}
// (X << C1) / C2 -> X * (C2 >> C1) if C1 is a multiple of C2.
if (isMultiple(C1Shifted, *C2, Quotient, IsSigned)) {
auto *Mul = BinaryOperator::Create(Instruction::Mul, X,
ConstantInt::get(Ty, Quotient));
auto *OBO = cast<OverflowingBinaryOperator>(Op0);
Mul->setHasNoUnsignedWrap(!IsSigned && OBO->hasNoUnsignedWrap());
Mul->setHasNoSignedWrap(OBO->hasNoSignedWrap());
return Mul;
}
}
if (!C2->isNullValue()) // avoid X udiv 0
if (Instruction *FoldedDiv = foldOpWithConstantIntoOperand(I))
return FoldedDiv;
}
if (match(Op0, m_One())) {
@ -1527,13 +1515,11 @@ Instruction *InstCombiner::visitFDiv(BinaryOperator &I) {
}
}
Value *LHS;
Value *RHS;
// -x / -y -> x / y
if (match(Op0, m_FNeg(m_Value(LHS))) && match(Op1, m_FNeg(m_Value(RHS)))) {
I.setOperand(0, LHS);
I.setOperand(1, RHS);
// -X / -Y -> X / Y
Value *X, *Y;
if (match(Op0, m_FNeg(m_Value(X))) && match(Op1, m_FNeg(m_Value(Y)))) {
I.setOperand(0, X);
I.setOperand(1, Y);
return &I;
}