https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93078
Alexander Monakov <amonakov at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |missed-optimization
Status|UNCONFIRMED |NEW
Last reconfirmed| |2019-12-27
CC| |amonakov at gcc dot gnu.org
Component|tree-optimization |target
Ever confirmed|0 |1
--- Comment #1 from Alexander Monakov <amonakov at gcc dot gnu.org> ---
> [...] not sure why dont auto-vectorize the function round directly to
> "roundps xmm0, XMMWORD PTR a[rip], 0"
This is because C round function is specified to use a non-standard rounding,
with halfway cases away from zero, not to nearest even. Hence a few extra
instructions to fix up halfway arguments.
For nearbyint, looks like CASE_CFN_NEARBYINT is not handled in
ix86_builtin_vectorized_function. Confirming for this case.
