This is the mail archive of the
mailing list for the GCC project.
Re: [trunk<-vta] Re: [vtab] Permit coalescing of user variables
On Wed, Jun 3, 2009 at 9:15 PM, Alexandre Oliva <firstname.lastname@example.org> wrote:
> On Jun ?3, 2009, Richard Guenther <email@example.com> wrote:
>> Btw, _is_ there really a such big effect with enabling the extra coalescing?
> I'm pretty sure I even posted SPEC results back when I first proposed
> these changes.
> I remember there was a huge effect in compile time for some
> machine-generated sources. ?Surely if enabling coalescing for inlined
> variables had such a huge effect, enabling it for non-inlined variables
> would have an even larger effect.
> Difference in performance was nothing to write home about, but when
> you're trying to squeeze the last bit of performance from a program,
> losing it to debug info you're not even interested in doesn't speak well
> of GCC.
Ok, I think the tristate option may be useful then. Can we enable
full coalescing at -O3 then? I'll defer to Ian to approve the patch.