{PING] [PATCH] Sign extension elimination

H. J. Lu hjl@lucon.org
Thu Apr 20 17:57:00 GMT 2006


On Thu, Apr 20, 2006 at 08:53:15PM +0300, Leehod Baruch wrote:
> > On Thu, Apr 20, 2006 at 10:23:21AM -0700, Mark Mitchell wrote:
> >> H. J. Lu wrote:
> >> > On Thu, Apr 20, 2006 at 09:39:23AM -0700, Mark Mitchell wrote:
> >> >> I'm not finding this discussion very illuminating.
> >> >>
> >> >> I'm trying to understand whether the current SEE pass is ready for
> >> >> inclusion in the compiler.  Roger has approved it on technical
> >> merits,
> >> >> but HJ has raised the issue that somehow this pass is a bad thing for
> >> >> x86-64.
> >> >
> >> > The current SEE implemented isn't designed for x86-64 and doesn't help
> >> > x86-64 at all, if it doesn't make it worse on x86-64. But its
> >> > infrastructure is needed for future x86-64 SEE work.
> >>
> >> OK.  So, then, there's no problem with incorporating the SEE
> >> implementation, and we proceed with that.
> >>
> >
> > Oh, it shouldn't be enabled for a target with any -On unless we can
> > demonstrate it does something useful.
> >
> I guess you referred here to x86-64.

Yes. I am curious how it performs for 32bit targets, like x86 or ppc32.


H.J.



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