[Bug target/63503] [AArch64] A57 executes fused multiply-add poorly in some situations

[e.menezes at samsung dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63503

--- Comment #23 from Evandro <e.menezes at samsung dot com> ---
(In reply to Wilco from comment #22)
> Unrolling alone isn't good enough in sum reductions. As I mentioned before,
> GCC doesn't enable any of the useful loop optimizations by default. So add
> -fvariable-expansion-in-unroller to get a good speedup with unrolling. Again
> these are all generic GCC issues.

Adding -fvariable-expansion-in-unroller when using -funroll-loops results in
practically the same code being emitted.