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From: "rguenther at suse dot de" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/53190] CSE (?) CSEs asms
Date: Thu, 03 May 2012 08:20:00 -0000 [thread overview]
Message-ID: <bug-53190-4-JyaOKqZWoS@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-53190-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53190
--- Comment #6 from rguenther at suse dot de <rguenther at suse dot de> 2012-05-03 08:19:17 UTC ---
On Thu, 3 May 2012, ubizjak at gmail dot com wrote:
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53190
>
> --- Comment #5 from Uros Bizjak <ubizjak at gmail dot com> 2012-05-03 08:15:00 UTC ---
> (In reply to comment #4)
>
> > So you say that it's correct for CSE to CSE asm()s if they have the same
> > asm string and the same asm operands in case the asm is not volatile? I was
> > not aware we would do that ;) (but yes, it sounds like a reasonable thing)
>
> There is nothing that prevents gcc from doing this...
>
> BTW: fpsr is FP *status* register, an x87 CC-like internal register. This asm
> should probably depend on fpcr, a FP *control* register.
>
> In fact, there are two FP control registers, x87 and SSE one. The later is not
> handled at all.
Well, the asm in glibc is simply
extern __inline __attribute__ ((__always_inline__)) long int
__attribute__ ((__nothrow__ )) lrintf (float __x)
{
long int __res;
__asm ("cvtss2si %1, %0" : "=r" (__res) : "xm" (__x));
return __res;
}
thus the CLOBBERs somehow magically appear anyways it seems.
next prev parent reply other threads:[~2012-05-03 8:20 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-02 12:47 [Bug rtl-optimization/53190] New: " rguenth at gcc dot gnu.org
2012-05-02 12:48 ` [Bug rtl-optimization/53190] " rguenth at gcc dot gnu.org
2012-05-02 17:09 ` pinskia at gcc dot gnu.org
2012-05-02 17:28 ` ubizjak at gmail dot com
2012-05-03 8:00 ` rguenth at gcc dot gnu.org
2012-05-03 8:16 ` ubizjak at gmail dot com
2012-05-03 8:20 ` rguenther at suse dot de [this message]
2012-05-03 8:39 ` ubizjak at gmail dot com
2012-05-03 9:20 ` aj at gcc dot gnu.org
2012-05-03 9:40 ` ubizjak at gmail dot com
2012-05-03 11:03 ` aj at gcc dot gnu.org
2012-05-03 11:43 ` ubizjak at gmail dot com
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