[llvm] r219583 - InstCombine: Simplify commonIDivTransforms
David Majnemer
david.majnemer at gmail.com
Sun Oct 12 01:34:24 PDT 2014
Author: majnemer
Date: Sun Oct 12 03:34:24 2014
New Revision: 219583
URL: http://llvm.org/viewvc/llvm-project?rev=219583&view=rev
Log:
InstCombine: Simplify commonIDivTransforms
A helper routine, MultiplyOverflows, was a less efficient
reimplementation of APInt's smul_ov and umul_ov. While we are here,
clean up the code so it's more uniform.
No functionality change intended.
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=219583&r1=219582&r2=219583&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp Sun Oct 12 03:34:24 2014
@@ -81,25 +81,15 @@ static Value *simplifyValueKnownNonZero(
/// MultiplyOverflows - True if the multiply can not be expressed in an int
/// this size.
-static bool MultiplyOverflows(ConstantInt *C1, ConstantInt *C2, bool sign) {
- uint32_t W = C1->getBitWidth();
- APInt LHSExt = C1->getValue(), RHSExt = C2->getValue();
- if (sign) {
- LHSExt = LHSExt.sext(W * 2);
- RHSExt = RHSExt.sext(W * 2);
- } else {
- LHSExt = LHSExt.zext(W * 2);
- RHSExt = RHSExt.zext(W * 2);
- }
-
- APInt MulExt = LHSExt * RHSExt;
-
- if (!sign)
- return MulExt.ugt(APInt::getLowBitsSet(W * 2, W));
+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);
- APInt Min = APInt::getSignedMinValue(W).sext(W * 2);
- APInt Max = APInt::getSignedMaxValue(W).sext(W * 2);
- return MulExt.slt(Min) || MulExt.sgt(Max);
+ return Overflow;
}
/// \brief True if C2 is a multiple of C1. Quotient contains C2/C1.
@@ -722,83 +712,83 @@ Instruction *InstCombiner::commonIDivTra
if (isa<SelectInst>(Op1) && SimplifyDivRemOfSelect(I))
return &I;
- if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
- if (Instruction *LHS = dyn_cast<Instruction>(Op0)) {
+ if (Instruction *LHS = dyn_cast<Instruction>(Op0)) {
+ const APInt *C2;
+ if (match(Op1, m_APInt(C2))) {
+ Value *X;
+ const APInt *C1;
+ bool IsSigned = I.getOpcode() == Instruction::SDiv;
+
// (X / C1) / C2 -> X / (C1*C2)
- if (Instruction::BinaryOps(LHS->getOpcode()) == I.getOpcode())
- if (ConstantInt *LHSRHS = dyn_cast<ConstantInt>(LHS->getOperand(1))) {
- if (!MultiplyOverflows(RHS, LHSRHS,
- I.getOpcode() == Instruction::SDiv))
- return BinaryOperator::Create(I.getOpcode(), LHS->getOperand(0),
- ConstantExpr::getMul(RHS, LHSRHS));
+ 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(I.getType(), 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(X->getType(), Quotient));
+ BO->setIsExact(I.isExact());
+ return BO;
}
- Value *X;
- const APInt *C1, *C2;
- if (match(RHS, m_APInt(C2))) {
- bool IsSigned = I.getOpcode() == Instruction::SDiv;
- 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(X->getType(), 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(X->getType(), Quotient));
- BO->setHasNoUnsignedWrap(
- !IsSigned &&
- cast<OverflowingBinaryOperator>(LHS)->hasNoUnsignedWrap());
- BO->setHasNoSignedWrap(
- cast<OverflowingBinaryOperator>(LHS)->hasNoSignedWrap());
- 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(X->getType(), 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)) {
- BinaryOperator *BO = BinaryOperator::Create(
- I.getOpcode(), X, ConstantInt::get(X->getType(), Quotient));
- BO->setIsExact(I.isExact());
- 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)) {
+ BinaryOperator *BO = BinaryOperator::Create(
+ I.getOpcode(), X, ConstantInt::get(X->getType(), 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)) {
- BinaryOperator *BO = BinaryOperator::Create(
- Instruction::Mul, X, ConstantInt::get(X->getType(), Quotient));
- BO->setHasNoUnsignedWrap(
- !IsSigned &&
- cast<OverflowingBinaryOperator>(LHS)->hasNoUnsignedWrap());
- BO->setHasNoSignedWrap(
- cast<OverflowingBinaryOperator>(LHS)->hasNoSignedWrap());
- return BO;
- }
+ // (X << C1) / C2 -> X * (C2 >> C1) if C1 is a multiple of C2.
+ if (IsMultiple(C1Shifted, *C2, Quotient, IsSigned)) {
+ BinaryOperator *BO = BinaryOperator::Create(
+ Instruction::Mul, X, ConstantInt::get(X->getType(), Quotient));
+ BO->setHasNoUnsignedWrap(
+ !IsSigned &&
+ cast<OverflowingBinaryOperator>(LHS)->hasNoUnsignedWrap());
+ BO->setHasNoSignedWrap(
+ cast<OverflowingBinaryOperator>(LHS)->hasNoSignedWrap());
+ return BO;
}
}
- }
- if (!RHS->isZero()) { // avoid X udiv 0
- if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
- if (Instruction *R = FoldOpIntoSelect(I, SI))
- return R;
- if (isa<PHINode>(Op0))
- if (Instruction *NV = FoldOpIntoPhi(I))
- return NV;
+ if (*C2 != 0) { // avoid X udiv 0
+ if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
+ if (Instruction *R = FoldOpIntoSelect(I, SI))
+ return R;
+ if (isa<PHINode>(Op0))
+ if (Instruction *NV = FoldOpIntoPhi(I))
+ return NV;
+ }
}
}
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