SPEC2000 comparison of LLVM-3.2 and coming GCC4.8 on x86/x86-64

David Edelsohn dje.gcc@gmail.com
Thu Feb 7 17:29:00 GMT 2013


On Thu, Feb 7, 2013 at 11:09 AM, Richard Biener
<richard.guenther@gmail.com> wrote:

> Also note that for SPEC -funroll-loops helps GCC (yes ... we don't
> enable that by default at -O3, we probably should).

Richi,

Are you suggesting enabling -funroll-loops by default at -O3?  When I
checked earlier this year, GCC was too aggressive with loop unrolling
on non-numerically-intensive code and that option was not uniformly
beneficial, unfortunately.  It would be a good change if GCC's
unrolling heuristics were better.

Thanks, David



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