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Re: Default x86-darwin to -mfpmath=sse, and update -arch settings

From: Richard Henderson <rth at redhat dot com>
To: Geoffrey Keating <geoffk at apple dot com>
Cc: Richard Guenther <richard dot guenther at gmail dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>
Date: Tue, 12 Apr 2005 09:11:31 -0700
Subject: Re: Default x86-darwin to -mfpmath=sse, and update -arch settings
References: <20050412014427.2F119556746@geoffk5.apple.com> <20050412103805.GD3384@redhat.com> <84fc9c0005041204171aa5ee10@mail.gmail.com> <09c25e6db15bcd0dfb16f3e4448b4532@apple.com>

On Tue, Apr 12, 2005 at 06:35:28AM -0700, Geoffrey Keating wrote:
> (If you wanted best performance, I think you'd want to use 
> -mfpmath=sse,387 right?)

No, actually that tends to be the worst option.  The register
allocator gets really confused and we spill things between
register files too much.  Further, the execution units are
actually shared on the current generation of processors, so
it's unlikely that we'll gain execution bandwidth by trying
to use both.

It has been suggested that we simply remove the option.  

r~

References:
- Default x86-darwin to -mfpmath=sse, and update -arch settings
  - From: Geoffrey Keating
- Re: Default x86-darwin to -mfpmath=sse, and update -arch settings
  - From: Richard Henderson
- Re: Default x86-darwin to -mfpmath=sse, and update -arch settings
  - From: Richard Guenther
- Re: Default x86-darwin to -mfpmath=sse, and update -arch settings
  - From: Geoffrey Keating

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