Displaying 4 results from an estimated 4 matches for "op1f".
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op1
2010 Mar 03
3
[LLVMdev] folding x * 0 = 0
...py of llvm, you can do so by adding it to the instcombine pass. We'd need IR enhancements to do this sort of thing for real in the mid-level optimizer, some thoughts are here:
> http://nondot.org/sabre/LLVMNotes/FloatingPointChanges.txt
>
Thanks, now it works. I inserted
if (Op1F->isNullValue())
return ReplaceInstUsesWith(I, Op1C); // X * 0 == 0
into llvm::InstCombiner::visitFMul
Why not at first create a compile time option for this so that the
code is already available for special purposes?
-Jochen
2010 Mar 03
2
[LLVMdev] folding x * 0 = 0
> You should check out the -enable-finite-only-fp-math and -enable-unsafe-fp-math options.
Good hint, but
llvm::UnsafeFPMath = true;
llvm::FiniteOnlyFPMathOption = true;
at the beginning of my code does not help.
I found llvm::Reassociate::OptimizeExpression in
llvm\lib\Transforms\Scalar\Reassociate.cpp
which looks like it does X * 0 = 0 for int, but it does not get called
for
2010 Mar 03
0
[LLVMdev] folding x * 0 = 0
On Mar 3, 2010, at 10:23 AM, Jochen Wilhelmy wrote:
>
>> You should check out the -enable-finite-only-fp-math and -enable-unsafe-fp-math options.
>
> Good hint, but
>
> llvm::UnsafeFPMath = true;
> llvm::FiniteOnlyFPMathOption = true;
>
> at the beginning of my code does not help.
> I found llvm::Reassociate::OptimizeExpression in
>
2010 Mar 03
0
[LLVMdev] folding x * 0 = 0
...by adding it to the instcombine pass. We'd need IR enhancements to do this sort of thing for real in the mid-level optimizer, some thoughts are here:
>> http://nondot.org/sabre/LLVMNotes/FloatingPointChanges.txt
>>
>
> Thanks, now it works. I inserted
>
> if (Op1F->isNullValue())
> return ReplaceInstUsesWith(I, Op1C); // X * 0 == 0
>
> into llvm::InstCombiner::visitFMul
>
> Why not at first create a compile time option for this so that the
> code is already available for special purposes?
I'm not sure how that would work,...