[llvm] r324922 - [InstCombine] various clean-ups for div transforms; NFC
Sanjay Patel via llvm-commits
llvm-commits at lists.llvm.org
Mon Feb 12 10:38:35 PST 2018
Author: spatel
Date: Mon Feb 12 10:38:35 2018
New Revision: 324922
URL: http://llvm.org/viewvc/llvm-project?rev=324922&view=rev
Log:
[InstCombine] various clean-ups for div transforms; NFC
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp?rev=324922&r1=324921&r2=324922&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp Mon Feb 12 10:38:35 2018
@@ -95,41 +95,6 @@ static Value *simplifyValueKnownNonZero(
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(Bin
}
// 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::simplifyDivRemOfSelec
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::commonIDivTra
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;
-
- // (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;
- }
+ const APInt *C2;
+ if (match(Op1, m_APInt(C2))) {
+ Value *X;
+ const APInt *C1;
- // (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;
- }
+ // (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(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 ((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;
}
- if (!C2->isNullValue()) // avoid X udiv 0
- if (Instruction *FoldedDiv = foldOpWithConstantIntoOperand(I))
- return FoldedDiv;
+ // (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(Bin
}
}
- 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;
}
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