Re: Emit vzeroupper after avx memcpy

Am 18.09.2013 16:46, schrieb Darren Salt:
> I demand that Chris Rankin may or may not have written...
> 
>> I've applied this patch to the xine-lib branch, but my attempts also to
>> merge it across from there to the xine-lib-1.2 branch have instead mangled
>> my local repository in ways I would not have believed possible...
> 
> I cherry-picked it and pushed it, assuming that all was well with it, but...
> 
> $ gdb misc/.libs/xine-list-1.2
> GNU gdb (GDB) 7.6 (Debian 7.6-5)
> Reading symbols from .../misc/.libs/xine-list-1.2...done.
> (gdb) run
> Starting program: .../misc/.libs/xine-list-1.2 
> warning: Could not load shared library symbols for linux-vdso.so.1.
> Do you need "set solib-search-path" or "set sysroot"?
> [Thread debugging using libthread_db enabled]
> Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
> 
> Program received signal SIGILL, Illegal instruction.
> sse_memcpy (to=0x7ffff5b62010, from=0x7ffff7fc7010, len=0) at memcpy.c:254
> 254	    __asm__ __volatile__ ("vzeroupper");
> (gdb) 
> 
> 
> This is on an Athlon II 240e.
> 
> 
> The attached patch SHOULD fix this (by using an SSE variant which has this
> extra instruction), but it needs some testing. Unfortunately, I can only test
> on hardware which does NOT have this instruction.
> 
> I'll commit it if it's fine on hw which has this instruction.
> 
> (CCing the one responsible for the breakage regardless of subscription to the
> list.)
> 

Ehh that doesn't make sense. Looks like vzeroupper got applied to
sse_memcpy instead of avx_memcpy. No idea why or how but I've got
nothing to do with it :-). My patch was against xine-lib 1.2 fwiw.

Roland




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