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From: Ian Ollmann <iano@cco.caltech.edu>
To: nobody@gcc.gnu.org
Cc: gcc-prs@gcc.gnu.org,
Subject: Re: optimization/8049: SSE unaligned vector stores crash with -O0
Date: Thu, 10 Oct 2002 18:06:00 -0000	[thread overview]
Message-ID: <20021011010601.10782.qmail@sources.redhat.com> (raw)

The following reply was made to PR optimization/8049; it has been noted by GNATS.

From: Ian Ollmann <iano@cco.caltech.edu>
To: Jan Hubicka <jh@suse.cz>
Cc: hubicka@gcc.gnu.org, <gcc-bugs@gcc.gnu.org>, <gcc-prs@gcc.gnu.org>,
        <gcc-gnats@gcc.gnu.org>
Subject: Re: optimization/8049: SSE unaligned vector stores crash with -O0
Date: Thu, 10 Oct 2002 17:58:22 -0700

 I think the problem is that the compiler is not properly padding data.
 _mm_store_ps is nearly unique in that its argument order is
 
 	_mm_store_ps( float*, vector );
 
 The 0x4 offset is to protect the float* that is written to the stack a few
 bytes earlier. The compiler needs to insert an extra 12 bytes of padding.
 In fact, it I swap the order of the arguments as follows:
 
 	_mm_store_ps( vector, float*)
 
 then the crash goes away.
 
 Ian
 
 ---------------------------------------------------
    Ian Ollmann, Ph.D.       iano@cco.caltech.edu
 ---------------------------------------------------
 


             reply	other threads:[~2002-10-11  1:06 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-10-10 18:06 Ian Ollmann [this message]
  -- strict thread matches above, loose matches on Subject: below --
2003-04-08 13:14 hubicka
2002-10-11 12:41 hubicka
2002-10-11  2:36 Jan Hubicka
2002-10-10 17:46 Ian Ollmann
2002-10-10 12:46 Ian Ollmann
2002-10-10 12:26 Jan Hubicka
2002-10-10 12:16 Ian Ollmann
2002-10-10 11:06 Jan Hubicka
2002-10-10 10:56 Ian Ollmann
2002-10-10 10:56 Jan Hubicka
2002-10-10 10:46 Ian Ollmann
2002-10-10  9:46 hubicka
2002-09-25 20:16 Tim Prince
2002-09-25 16:06 iano

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