From: Markus Trippelsdorf <markus@trippelsdorf.de>
To: "Manuel López-Ibáñez" <lopezibanez@gmail.com>
Cc: Mathieu Malaterre <malat@debian.org>,
gcc-help <gcc-help@gcc.gnu.org>, Andrew Haley <aph@redhat.com>
Subject: Re: -ffloat-store behavior (Re: Susprising behavior of gcc on x86 (-m32))
Date: Wed, 09 Sep 2015 05:19:00 -0000 [thread overview]
Message-ID: <20150909051931.GA432@x4> (raw)
In-Reply-To: <55EF53AC.9020306@gmail.com>
On 2015.09.08 at 23:31 +0200, Manuel López-Ibáñez wrote:
> On 08/09/15 22:05, Mathieu Malaterre wrote:
> >
> > Ok, I think I understand now. -O0 did produce code that is compatible
> > with -ffloat-store. However I am still required to use -ffloat-store
> > (explicitly) for any other optimization (at least required with -O2 in
> > my case).
>
> You are not required to use -ffloat-store, neither is -ffloat-store guaranteed
> to work. Please read https://gcc.gnu.org/wiki/FAQ#PR323
And please note that he whole issue has nothing to do with gcc. See
e.g.:
http://stackoverflow.com/questions/31973139/gcc-m32-option-changes-floating-point-rounding-when-not-running-valgrind
for a similar example.
--
Markus
next prev parent reply other threads:[~2015-09-09 5:19 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-08 20:00 Mathieu Malaterre
2015-09-08 20:05 ` Mathieu Malaterre
2015-09-08 21:31 ` Manuel López-Ibáñez
2015-09-09 5:19 ` Markus Trippelsdorf [this message]
2015-09-09 6:08 ` Mathieu Malaterre
2015-09-09 7:19 ` Mathieu Malaterre
2015-09-09 8:58 ` Andrew Haley
2015-09-09 9:24 ` Manuel López-Ibáñez
2015-09-09 13:32 ` Mathieu Malaterre
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