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Re: [patch 9/N][PA] convert to fma

From: "H.J. Lu" <hjl dot tools at gmail dot com>
To: "Joseph S. Myers" <joseph at codesourcery dot com>
Cc: Richard Henderson <rth at twiddle dot net>, John David Anglin <dave at hiauly1 dot hia dot nrc dot ca>, gcc-patches at gcc dot gnu dot org, dave dot anglin at nrc-cnrc dot gc dot ca
Date: Sun, 14 Nov 2010 07:58:50 -0800
Subject: Re: [patch 9/N][PA] convert to fma
References: <20101113002358.541EB4D30@hiauly1.hia.nrc.ca> <4CDF2798.5010007@twiddle.net> <AANLkTikQ8=fjHHKWzkeS+QfJjJ+wrpRT85kaQgrzNiHn@mail.gmail.com> <Pine.LNX.4.64.1011141522040.3197@digraph.polyomino.org.uk>

On Sun, Nov 14, 2010 at 7:34 AM, Joseph S. Myers
<joseph@codesourcery.com> wrote:
>>
>> That is true. GCC doesn't even preserve kinds (Q vs S) of NaNs on
>> x86 with SSE FP math.
>
> Non-preservation of the kind of NaN (if it should otherwise be preserved
> for IEEE semantics) should be conditioned on HONOR_SNANS (mode). ?(The
> documentation of -fsignaling-nans does warn that not everything that
> should be conditioned on it necessarily is.)

But -fsignaling-nans doesn't address

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45365

since GCC treat FP add and multiply commutative even when both
operands are NaNs.

-- 
H.J.

References:
- Re: [patch 9/N][PA] convert to fma
  - From: John David Anglin
- Re: [patch 9/N][PA] convert to fma
  - From: Richard Henderson
- Re: [patch 9/N][PA] convert to fma
  - From: H.J. Lu
- Re: [patch 9/N][PA] convert to fma
  - From: Joseph S. Myers

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