Adds missing TLI check for library simplification of

* pow(x, 0.5) -> fabs(sqrt(x)) 
* pow(2.0, x) -> exp2(x)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188656 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Michael Kuperstein
2013-08-19 06:55:47 +00:00
parent a0e735ee16
commit 2063637fa7
3 changed files with 31 additions and 3 deletions

View File

@ -1133,9 +1133,11 @@ struct PowOpt : public UnsafeFPLibCallOptimization {
Value *Op1 = CI->getArgOperand(0), *Op2 = CI->getArgOperand(1);
if (ConstantFP *Op1C = dyn_cast<ConstantFP>(Op1)) {
if (Op1C->isExactlyValue(1.0)) // pow(1.0, x) -> 1.0
// pow(1.0, x) -> 1.0
if (Op1C->isExactlyValue(1.0))
return Op1C;
if (Op1C->isExactlyValue(2.0)) // pow(2.0, x) -> exp2(x)
// pow(2.0, x) -> exp2(x)
if (Op1C->isExactlyValue(2.0) && TLI->has(LibFunc::exp2))
return EmitUnaryFloatFnCall(Op2, "exp2", B, Callee->getAttributes());
}
@ -1145,7 +1147,8 @@ struct PowOpt : public UnsafeFPLibCallOptimization {
if (Op2C->getValueAPF().isZero()) // pow(x, 0.0) -> 1.0
return ConstantFP::get(CI->getType(), 1.0);
if (Op2C->isExactlyValue(0.5)) {
if (Op2C->isExactlyValue(0.5) &&
TLI->has(LibFunc::sqrt) && TLI->has(LibFunc::fabs)) {
// Expand pow(x, 0.5) to (x == -infinity ? +infinity : fabs(sqrt(x))).
// This is faster than calling pow, and still handles negative zero
// and negative infinity correctly.