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Re: [PATCH] Fix up floatunsv{4,8}siv{4,8}sf2
- From: Uros Bizjak <ubizjak at gmail dot com>
- To: Jakub Jelinek <jakub at redhat dot com>
- Cc: Richard Henderson <rth at redhat dot com>, gcc-patches at gcc dot gnu dot org
- Date: Thu, 3 Nov 2011 20:01:21 +0100
- Subject: Re: [PATCH] Fix up floatunsv{4,8}siv{4,8}sf2
- References: <20111103175440.GC1052@tyan-ft48-01.lab.bos.redhat.com>
On Thu, Nov 3, 2011 at 6:54 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> As mentioned in the last mail, the testcase in that patch
> shows a bug in the unsigned int -> float vectorization
> on i?86/x86_64. ?E.g. 0x8000008fU converted to float
> by scalar code is 0x1.000002p+31, but by vector code
> is 0x1p+31, i.e. one ulp smaller.
< stuff >
> So, what do you prefer and do you want the expander to be moved into
> i386.c or kept like this? ?Do we perhaps want for -ffast-math
> keep the slightly faster, but imprecise version (I'd prefer not to)?
IMO, let's go with the fastest solution (X313c), but please move
expander to i386.c.
Also, -ffast-math should use the same version. At the end of the day,
real-world applications do not comprise only unsigned conversions ;)
Uros.