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Re: [PATCH] Support Cell SPU floating point
- From: "Richard Guenther" <richard dot guenther at gmail dot com>
- To: "trevor_smigiel at playstation dot sony dot com" <trevor_smigiel at playstation dot sony dot com>
- Cc: gcc-patches <gcc-patches at gcc dot gnu dot org>, Andrew_Pinski at playstation dot sony dot com, "Ulrich Weigand" <uweigand at de dot ibm dot com>, Russell_Olsen at playstation dot sony dot com
- Date: Wed, 29 Aug 2007 10:55:11 +0200
- Subject: Re: [PATCH] Support Cell SPU floating point
- References: <20070829001149.GF1923@playstation.sony.com>
On 8/29/07, trevor_smigiel@playstation.sony.com
<trevor_smigiel@playstation.sony.com> wrote:
> This patch does three things:
>
> 1) Add Cell SPU extended single precision format to real.c
> 2) Define macros for constant folding of denormalized numbers
> 3) Define macros to prevent certain optimizations on denorms
>
> The latter 2 parts are necessary to get proper constant folding and
> optimization on SPU which does not fully support IEEE floats. A comment
> in real.c describes the differences:
>
> /* SPU Single Precision (Extended-Range Mode) format is the same as IEEE
> single precision with the following differences:
...
> - the only supported rounding mode is trunction (towards zero)
Uh. You know you need to enable -frounding-math always then? Or do SPU users
not care if the compiler optimizes as if the rounding mode would be round to
nearest/even?
Richard.