On 24 January 2017 at 18:15, Bernd Schmidt <bschm...@redhat.com> wrote:
> On 01/24/2017 06:03 PM, Christophe Lyon wrote:
>>
>> Ha... the regression occurred between r 244818 and r 244816,
>> and I read r 244816 ChangeLog too quickly and did not notice
>> it was modifying ifcvt.c in addition to x86-only files.
>>
>> So it's likely that it's your other patch for pr78634
>> that caused the regression I mentioned. Does it make
>> more sense?
>
>
> That's possible. That added a missing cost check, so the question becomes -
> is the change in generated assembly sensible, given the selected CPU type?
>
I can now confirm that the change is indeed caused by r244816 (pr78634).
The difference in the generated asm is:
- vmov d17, r0, r1
- vmov d16, r2, r3
- vcmp.f64 d17, d16
+ vmov d16, r0, r1
+ vmov d17, r2, r3
+ vcmp.f64 d16, d17
vmrs APSR_nzcv, FPSCR
- vselvs.f64 d16, d16, d17
+ vmovvs.f64 d16, d17
which, besides swapping d16 and d17, summarizes to
- vselvs.f64 d16, d16, d17
+ vmovvs.f64 d16, d17
I'm not sure if there is a "best" one ?
>
> Bernd
