[Liboil] Liboil slower than plain gcc?

David Schleef ds at schleef.org
Sat Dec 15 10:18:20 PST 2007


On Sat, Dec 15, 2007 at 01:08:51PM -0500, Jason Sewall wrote:
> it ends up being about 3-4x slower than gcc with this:
> for(int i = 0; i < size; ++i)
>      dest[i] = c1*src1[i]+c2*src2[i];
> 
> If they are compiled with:
> -DNDEBUG -O3 -funroll-all-loops -march=prescott --std=c99 -msse3 -mfpmath=sse
> 
> Am I doing something grossly wrong?

Yes, you're assuming that someone has bothered to write optimizations
for that function.



dave...




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