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Differential D72319 Diff 237069 llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp

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llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp

Show First 20 Lines • Show All 1,233 Lines • ▼ Show 20 Lines if (match(Op0, m_OneUse(m_FDiv(m_Value(X), m_Value(Y)))) &&
return BinaryOperator::CreateFDivFMF(X, YZ, &I); return BinaryOperator::CreateFDivFMF(X, YZ, &I);
} }
if (match(Op1, m_OneUse(m_FDiv(m_Value(X), m_Value(Y)))) && if (match(Op1, m_OneUse(m_FDiv(m_Value(X), m_Value(Y)))) &&
(!isa<Constant>(Y) || !isa<Constant>(Op0))) { (!isa<Constant>(Y) || !isa<Constant>(Op0))) {
// Z / (X / Y) => (Y * Z) / X // Z / (X / Y) => (Y * Z) / X
Value *YZ = Builder.CreateFMulFMF(Y, Op0, &I); Value *YZ = Builder.CreateFMulFMF(Y, Op0, &I);
return BinaryOperator::CreateFDivFMF(YZ, X, &I); return BinaryOperator::CreateFDivFMF(YZ, X, &I);
} }
// Z / (1.0 / Y) => (Y * Z)
//
// This is a special case of Z / (X / Y) => (Y * Z) / X, with X = 1.0. The
// m_OneUse check is avoided because even in the case of the multiple uses
// for 1.0/Y, the number of instructions remain the same and a division is
// replaced by a multiplication.
if (match(Op1, m_FDiv(m_SpecificFP(1.0), m_Value(Y))))
return BinaryOperator::CreateFMulFMF(Y, Op0, &I);
spatelUnsubmitted
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I don't think these constant checks are necessary. (I'm not sure why they are part of the existing code either - maybe some corner case with denorm values?)

If Y is a constant, 1.0/C will get constant folded and Z/C' will eventually get folded too, so this should just get to canonical form quicker. The 'Z' is constant pattern is similar.

FDiv with constant operand are generally handled within:
foldFDivConstantDivisor()
foldFDivConstantDividend()

spatel: I don't think these constant checks are necessary. (I'm not sure why they are part of the…
} }
if (I.hasAllowReassoc() && Op0->hasOneUse() && Op1->hasOneUse()) { if (I.hasAllowReassoc() && Op0->hasOneUse() && Op1->hasOneUse()) {
// sin(X) / cos(X) -> tan(X) // sin(X) / cos(X) -> tan(X)
// cos(X) / sin(X) -> 1/tan(X) (cotangent) // cos(X) / sin(X) -> 1/tan(X) (cotangent)
Value *X; Value *X;
bool IsTan = match(Op0, m_Intrinsic<Intrinsic::sin>(m_Value(X))) && bool IsTan = match(Op0, m_Intrinsic<Intrinsic::sin>(m_Value(X))) &&
match(Op1, m_Intrinsic<Intrinsic::cos>(m_Specific(X))); match(Op1, m_Intrinsic<Intrinsic::cos>(m_Specific(X)));
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