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Disable an xform we've had for a long time, pow(x,0.5) -> sqrt.

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This is not safe for all inputs.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49458 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2008-04-10 02:07:51 +00:00
parent 5d4ed3ba11
commit 0c1963099f
1 changed files with 8 additions and 0 deletions
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8
lib/Transforms/IPO/SimplifyLibCalls.cpp
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@ -1179,9 +1179,17 @@ public:
// pow(x, 0.0) -> 1.0
return ReplaceCallWith(CI, ConstantFP::get(CI->getType(), 1.0));
} else if (Op2C->isExactlyValue(0.5)) {
// FIXME: This is not safe for -0.0 and -inf. This can only be done when
// 'unsafe' math optimizations are allowed.
// x pow(x, 0.5) sqrt(x)
// ---------------------------------------------
// -0.0 +0.0 -0.0
// -inf +inf NaN
#if 0
// pow(x, 0.5) -> sqrt(x)
Value *Sqrt = CallInst::Create(SLC.get_sqrt(), Op1, "sqrt", CI);
return ReplaceCallWith(CI, Sqrt);
#endif
} else if (Op2C->isExactlyValue(1.0)) {
// pow(x, 1.0) -> x
return ReplaceCallWith(CI, Op1);