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Re: GCC viciously beaten by ICC in trig test!
On Mon, Mar 15, 2004 at 10:13:13AM -0800, Joe Buck wrote:
> On Mon, Mar 15, 2004 at 07:11:04AM +0100, Jakub Jelinek wrote:
> > Well, the inlines shouldn't be removed, but guarded with
> > # if !__GNUC_PREREQ (MAJOR,MINOR)
> > ...
> > # endif
> > where MAJOR, MINOR is the first __GNUC__ and __GNUC_MINOR__ of GCC which
> > can handle all cases the same or better than the glibc inline.
>
> Is the proper requirement "all cases"? What if the glibc inline is
> sometimes better, but sometimes far worse?
Ok, all cases is not necessary, but good judgement needs to be applied.
I've tried to look at a few inlines today, e.g. signbit in GCC is as good
as glibc builtin, which means __builtin_signbit should be used,
but already on IA-32 __builtin_signbitl is worse.
Although GCC 3.5 has really many math builtins, most of them do nothing
and thus are usually worse than what GLIBC provides (tried e.g. exp, tan).
Jakub