Subject: Re: -mstrict-align on powerpc
To: Jason Thorpe <>
From: Nathan J. Williams <>
List: tech-toolchain
Date: 03/16/2003 13:41:29
Jason Thorpe <> writes:

> On Sunday, March 16, 2003, at 02:37  AM, Juergen Hannken-Illjes wrote:
> > At least 1.6 has a shared/powerpc with X, games and text.
> > Therefore the powerpc should use a feature set useable on all cpus.
> Yah, I agree that -mstrict-align should be the default if not specific
> CPU flag is specified.  But if a CPU that can handle unaligned access
> is specified, I think we ought to allow unaligned access in that case.

Why? The performance of unaligned fetches always sucks, even when they
don't trap. I think we should be going the other way: actively
preventing, if not forbidding, unaligned data structures even on CPUs
that don't require alignment, to improve performance.

        - Nathan