[Bug target/55752] __builtin_ia32_ldmxcsr / __builtin_ia32_stmxcsr are not scheduling barriers

[rguenther at suse dot de]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55752

--- Comment #2 from rguenther at suse dot de <rguenther at suse dot de> 2012-12-20 13:07:20 UTC ---
On Thu, 20 Dec 2012, ubizjak at gmail dot com wrote:

> 
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55752
> 
> --- Comment #1 from Uros Bizjak <ubizjak at gmail dot com> 2012-12-20 12:59:40 UTC ---
> The RTXes that corresponds to builtins are all declared unspec_volatile.
> According to the comment in sched-deps.c, around line 2723, it is assumed that
> unspec_volatile clobbers all registers.

Ok, it seems it's TER that moves the subtraction.

Richard.