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Re: P4 support question (-> FAQ?)
- To: Will Menninger <william dot l dot menninger at boeing dot com>, gcc at gcc dot gnu dot org
- Subject: Re: P4 support question (-> FAQ?)
- From: Jean Francois Martinez <jfm2 at club-internet dot fr>
- Date: Thu, 24 May 2001 19:22:38 +0200
- References: <200105241551.IAA06493@ncc1701e.to.hac.com>
- Reply-To: jfm2 at club-internet dot fr
On Thursday 24 May 2001 17:51, Will Menninger wrote:
> Is there a way to add a question to the gcc FAQ database on the web?
> Either way, I'd like to see this question added to the platform specific
> section (and hopefully answered): What is the timeline (if any) for
> supporting Pentium 4 specific instructions (e.g. SSE-2) in gcc? Is this
> being worked on or expected to occur in a specific release of gcc?
> Please refer me to the appropriate link if this question is answered
> somewhere in the gcc web pages.
My experince with gcc 2.x is that use of specific instructions brings only
minimal sped increases in 99 % of cases, the real speed boost is given by
using sequences who are optimized for processor. In other words -march=
(use of specific instructions) brins very little improvement over -mcpu=
(optimized for specific cpu but using only 386 instructions).
This could change the day gcc genartes MMX instructions but for now the
question should be when will gcc be able to optimize for PIV?