[Bug middle-end/90283] 519.lbm_r is 7%-10% slower with -Ofast -march=native and both LTO and PGO than with GCC 8

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90283

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2019-04-30
     Ever confirmed|0                           |1

--- Comment #3 from Martin Liška <marxin at gcc dot gnu.org> ---
The perf comes from an Intel Skylake server machine.

The number of fma is very similar:
grep fma bad.report.txt | wc -l
126
grep fma good.report.txt | wc -l
128

But the assembly is shuffled quite significantly after the change. Can you
Richard Sandiford please take a look?