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[Bug c/26653] Wrong assembly generated with -O2, -O OK for cinelerra source item
- From: "mtodorov at alu dot hr" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 12 Mar 2006 18:06:34 -0000
- Subject: [Bug c/26653] Wrong assembly generated with -O2, -O OK for cinelerra source item
- References: <bug-26653-1064@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #4 from mtodorov at alu dot hr 2006-03-12 18:06 -------
Subject: Re: Wrong assembly generated with -O2, -O OK for
cinelerra source item
On Sun, 12 Mar 2006, pinskia at gcc dot gnu dot org wrote:
> ------- Comment #3 from pinskia at gcc dot gnu dot org 2006-03-12 18:01 -------
> (In reply to comment #2)
> The inline-asm is just wrong. X means any register or memory which means it
> could pick esp or xmm3 without caring that much.
>
> Also the code is hiding all the mmx register uses from the compiler so the
> compiler could mess up and use one of those.
I cannot question your expertise on this.
Why then -O passes, and does it generate right code? Does 4.0.3 do the
worng thing when compiling this without complaint?
How can I know that this modification to assembly I've been given now will
not cause libjpeg-mmx to work wrong in subtle ways?
(I am not an expert in nasm assembly ..., :-(
Sincerely,
Mirsad
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26653