[Bug c/70255] change of the order of summation of floating point numbers despite no-associative-math

[shatz at dsit dot co.il]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70255

--- Comment #14 from shatz at dsit dot co.il ---
(In reply to Marek Polacek from comment #13)
> So what exactly is not documented?
> 
> And I disagree that a warning isn't necessary just because something is
> documented -- that applies for almost any warning.

It is not documented that __attribute__((optimize(""))) works reliably when it
is present in the source before the function body, but is ignored (always?
occasionally?) when it specified after function body.