[Bug target/97127] FMA3 code transformation leads to slowdown on Skylake

[amonakov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97127

--- Comment #17 from Alexander Monakov <amonakov at gcc dot gnu.org> ---
To me this suggests that in fact it's okay to carry the combined form in RTL up
to register allocation, but RA should decompose it to load+fma instead of
inserting a register copy that preserves the live operand.

(not a fan of "RA should deal with it" theme, but here it does look like the
most appropriate resolution)