[Qemu-devel] possible qemu miscompilation by latest gcc

[John Regehr <regehr@cs.utah.edu>]

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