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Re: gcc 4.3.0 i386 default question
- From: Jan Hubicka <hubicka at ucw dot cz>
- To: Joel Sherrill <joel dot sherrill at oarcorp dot com>
- Cc: GCC List <gcc at gcc dot gnu dot org>
- Date: Wed, 12 Mar 2008 16:37:39 +0100
- Subject: Re: gcc 4.3.0 i386 default question
- References: <47D7F58E.email@example.com>
> Did the default i386 CPU model that gcc generates
> code for change between 4.2.x and 4.3.0? I didn't
> see anything in the release notes that jumps out at
> me about this.
There wasnt any intend to change the codebase. However the default
tunning now has changed to "generic" model. Perhaps some non-i386
instructions got in as a mistake. Can you be more specific about what
instructions you found?
> Using i386-rtems4.9 as the target, I was running
> code compiled by gcc 4.3.0 on a vanilla i386 and
> was getting illegal instruction exceptions. I looked
> at the assembly and noticed instructions which were
> not on the i386. Obviosuly, when I added -mtune=i386
> and the issue went away.
> This probably impacts no one on a GNU/Linux computer
> since very few of those are base i386's anymore. Just
> venerable embedded systems. :)
> Joel Sherrill, Ph.D. Director of Research & Development
> joel.sherrill@OARcorp.com On-Line Applications Research
> Ask me about RTEMS: a free RTOS Huntsville AL 35805
> Support Available (256) 722-9985