[Bug target/110649] [14 Regression] 25% sphinx3 spec2006 regression on Ice Lake and zen between g:acaa441a98bebc52 (2023-07-06 11:36) and g:55900189ab517906 (2023-07-07 00:23)

[hubicka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110649

Jan Hubicka <hubicka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=110692

--- Comment #8 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
So in mgau_eval the inner loop is vectorized and peeled, epilogues are
vectorized and fully unrolled. The resulting code seems bit more complicated
then it needs to be.
I do not think the problems in profile updates are very iportant and actually
should affect overall performance much.

vector_gautbl_eval_logs3 seems similar but we run out of registers, so there
profile may be more relevant

I added to PR110692 oversimplified example of this pattern.  I think we could
get overall codegen better...