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Reapply commit 143028 with a fix: the problem was casting a ConstantExpr Mul

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using BinaryOperator (which only works for instructions) when it should have
been a cast to OverflowingBinaryOperator (which also works for constants).
While there, correct a few other dubious looking uses of BinaryOperator.
Thanks to Chad Rosier for the testcase.  Original commit message:
My super-optimizer noticed that we weren't folding this expression to
true: (x *nsw x) sgt 0, where x = (y | 1).  This occurs in 464.h264ref.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143125 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Duncan Sands
2011-10-27 19:16:21 +00:00
parent 6eb1ed8c9c
commit 32a43cc0fc
4 changed files with 95 additions and 9 deletions
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5
lib/Analysis/InstructionSimplify.cpp
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@@ -758,7 +758,8 @@ static Value *SimplifyMulInst(Value *Op0, Value *Op1, const TargetData *TD,
Value *X = 0, *Y = 0;
if ((match(Op0, m_IDiv(m_Value(X), m_Value(Y))) && Y == Op1) || // (X / Y) * Y
(match(Op1, m_IDiv(m_Value(X), m_Value(Y))) && Y == Op0)) { // Y * (X / Y)
BinaryOperator *Div = cast<BinaryOperator>(Y == Op1 ? Op0 : Op1);
PossiblyExactOperator *Div =
cast<PossiblyExactOperator>(Y == Op1 ? Op0 : Op1);
if (Div->isExact())
return X;
}
@@ -842,7 +843,7 @@ static Value *SimplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
Value *X = 0, *Y = 0;
if (match(Op0, m_Mul(m_Value(X), m_Value(Y))) && (X == Op1 || Y == Op1)) {
if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1
BinaryOperator *Mul = cast<BinaryOperator>(Op0);
OverflowingBinaryOperator *Mul = cast<OverflowingBinaryOperator>(Op0);
// If the Mul knows it does not overflow, then we are good to go.
if ((isSigned && Mul->hasNoSignedWrap()) ||
(!isSigned && Mul->hasNoUnsignedWrap()))