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Re: {PING] [PATCH] Sign extension elimination
- From: "Leehod Baruch" <leehod dot baruch at weizmann dot ac dot il>
- To: "H. J. Lu" <hjl at lucon dot org>
- Cc: "Mark Mitchell" <mark at codesourcery dot com>, "Toon Moene" <toon at moene dot indiv dot nluug dot nl>, "Daniel Berlin" <dberlin at dberlin dot org>, "Mircea Namolaru" <namolaru at il dot ibm dot com>, gcc-patches at gcc dot gnu dot org, leehod at gmail dot com, "Roger Sayle" <roger at eyesopen dot com>
- Date: Thu, 20 Apr 2006 20:53:15 +0300 (IDT)
- Subject: Re: {PING] [PATCH] Sign extension elimination
> 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.
On PPC the improvement was demonstrated.
Leehod.