This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: gcc/gcc config.gcc config/sparc/linux.h config ...


> 
> Brad Lucier wrote:
> 
> > Also, this is a performance increase of about a factor of 100, and it seems
> > to be extremely simple and clean; should it not also be installed on the
> > 3.1 branch?
> 
> Are you sure you really *want* underflow-flushed-to-zero ?  [ You're one
> of our (i.e., gcc testers') IEEE-conformant users - at least so I
> thought ]

It's only enabled with -funsafe-math-optimizations or -ffast-math, so,
to me, it's OK.

> I got about 40 % speedup on our Numerical Weather Forecasting code [on
> Alpha], but that's because underflows are (naturally) very rare in such
> code (it's not impossible, given enough careful programming effort, to
> eradicate them completely) ...

Certainly there are other computational scientists at Purdue who are not so
tied to IEEE semantics and who would benefit from this a lot.

Brad


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]