[Bug middle-end/77515] GCC fusing of multiply-add ["FMA"] occurring at "-O3" withOUT "-ffast-math" and withOUT "-ffp-contract=fast"

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77515

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
>This seems to be in violation of preservation of exactly the same results

Huh?  Where did you read that?  

Also GCC defaults not to on but to:
-ffp-contract=fast


Read:
https://gcc.gnu.org/onlinedocs/gcc-6.2.0/gcc/Optimize-Options.html#index-ffp-contract-715

Where it says that :).