[Bug tree-optimization/84114] global reassociation pass prevents fma usage, generates slower code

[sje at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84114

--- Comment #9 from Steve Ellcey <sje at gcc dot gnu.org> ---

> Can you let me know if my workaround helped? If useful I could backport it
> to GCC7 as well.

Yes, the patch helped.  I ran spec 2017 fp rate and saw a small improvement
(0.7%).  Most of the speed up was in 508.namd_r, 526.blender_r, and 544.nab_r.
507.cactuBSSN_r and 511.povray_r slowed down a little bit.