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Fix m_Not and m_Neg to not match random ConstantInt's. Before

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these would try hard to match constants by inverting the bits
and recursively matching.  There are two problems with this:
1) some patterns would match when we didn't want them to (theoretical)
2) this is insanely expensive to do, and most often pointless.

This was apparently useful in just 2 instcombine cases, which I
added code to handle explicitly.  This change speeds up 'opt'
time on 176.gcc by 1% and produces bitwise identical code.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123518 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2011-01-15 05:52:27 +00:00
parent 67920320b2
commit 4de2c76542
1 changed files with 0 additions and 4 deletions
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4
include/llvm/Support/PatternMatch.h
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@ -521,8 +521,6 @@ struct not_match {
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
if (CE->getOpcode() == Instruction::Xor)
return matchIfNot(CE->getOperand(0), CE->getOperand(1));
if (ConstantInt *CI = dyn_cast<ConstantInt>(V))
return L.match(ConstantExpr::getNot(CI));
return false;
}
private:
@ -557,8 +555,6 @@ struct neg_match {
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
if (CE->getOpcode() == Instruction::Sub)
return matchIfNeg(CE->getOperand(0), CE->getOperand(1));
if (ConstantInt *CI = dyn_cast<ConstantInt>(V))
return L.match(ConstantExpr::getNeg(CI));
return false;
}
private: