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Re: Bug in builtin_floor optimization

From: Richard Henderson <rth at redhat dot com>
To: Roger Sayle <roger at eyesopen dot com>
Cc: Dale Johannesen <dalej at apple dot com>, gcc at gcc dot gnu dot org
Date: Tue, 23 Aug 2005 09:53:18 -0700
Subject: Re: Bug in builtin_floor optimization
References: <d0ec9e1821755ff535ccc357788f3e41@apple.com> <Pine.LNX.4.44.0508230907540.18224-100000@www.eyesopen.com>

On Tue, Aug 23, 2005 at 09:28:50AM -0600, Roger Sayle wrote:
> Good catch.  This is indeed a -ffast-math (or more precisely a
> flag_unsafe_math_optimizations) transformation.  I'd prefer to
> keep these transformations with -ffast-math, as Jan described them
> as significantly helping SPEC's mesa when they were added.

Are you sure it was "(float)floor(d)"->"floorf((float)d)" that
helped mesa and not "(float)floor((double)f)"->"floorf(f)" ?

It wouldn't bother me if the first transformation went away
even for -ffast-math.  It seems egregeously wrong.

r~

Follow-Ups:
- Re: Bug in builtin_floor optimization
  - From: Dale Johannesen

References:
- Bug in builtin_floor optimization
  - From: Dale Johannesen
- Re: Bug in builtin_floor optimization
  - From: Roger Sayle

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