[Bug target/92686] Inefficient mask operation for 128/256-bit vector VCOND_EXPR under avx512f

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92686

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2019-11-27
     Ever confirmed|0                           |1
           Severity|normal                      |enhancement

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
It would be definitely nice to have this.  Maybe add a tunable whether to use
mask registers for SSE/AVX2?  Is there any boost frequency penalty for using
them?  Using mask registers also looks like a way to reduce register pressure
(in case the register pressure is not on the masks side).