On Fri, Nov 07, 2014 at 05:13:36PM +0100, Hanno Böck wrote:
> valgrind says on id:000053,src:000000,op:flip1,pos:879:
> ELF Header:
> vex x86->IR: unhandled instruction bytes: 0xC5 0xF8 0x77 0xE8
> ==6217== valgrind: Unrecognised instruction at address 0x410f7a7.

You might have to upgrade your valgrind. That is VZEROUPPER an AVX
instruction that should be supported since valgrind 3.8.0 on x86_64.
Ah, you are running 32bit? Then valgrind does indeed not support it.

Cheers,

Mark