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Date: Wed, 20 Jan 2010 23:15:07 -0700
From: John Regehr <regehr@cs.utah.edu>
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Subject: [Qemu-devel] possible qemu miscompilation by latest gcc
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To: qemu-devel@nongnu.org

Hi folks-

Just wanted to let you know that perhaps the function 
helper_neon_rshl_s8() is being miscompiled by the latest gcc.

I'm using qemu 0.12.2 and gcc rev 156103, which is a pre-version of gcc 
4.5.  This is on an x86 machine running Ubuntu 9.10.

At -O2 or higher this is the resulting object code:

00002060 <helper_neon_rshl_s8>:
     2060:	31 c0                	xor    %eax,%eax
     2062:	c3                   	ret

If this is not the intended result, then either the function has a 
latent bug or else the compiler is doing something bad.

Hope this is helpful,

John Regehr