Fix PR44281 (bad RA with global regs)

[Jeff Law]

On 04/27/2016 03:02 PM, Bernd Schmidt wrote:
> On 04/27/2016 10:59 PM, Jeff Law wrote:
>>>     PR rtl-optimization/44281
>>>     * hard-reg-set.h (struct target_hard_regs): New field
>>>     x_fixed_nonglobal_reg_set.
>>>     (fixed_nonglobal_reg_set): New macro.
>>>     * reginfo.c (init_reg_sets_1): Initialize it.
>>>     * ira.c (setup_alloc_regs): Use fixed_nonglobal_reg_set instead
>>>     of fixed_reg_set.
>>>
>>>     PR rtl-optimization/44281
>>>     * gcc.target/i386/pr44281.c: New test.
>> So  my recollection of where we left things was that we needed to
>> dataflow information fixed for implicit uses/sets in asms.  With that
>> infrastructure in place I think we'll be ready to resolve this old
>> issue.  Right?
>
> Yeah. I had prepared the following, and I was planning on getting around
> to retesting it with current trunk on top of the other patch, but I
> haven't quite got there yet.
Looks like it'll do the trick to me.  Consider the combination of the 
two patches pre-approved once you've run it through the usual testing.

Thanks,
Jeff