[Bug middle-end/102930] equal values appear to be different due to missing correct rounding in libc

[vincent-gcc at vinc17 dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102930

--- Comment #3 from Vincent Lefèvre <vincent-gcc at vinc17 dot net> ---
(In reply to Jakub Jelinek from comment #2)
> I think there is nothing that can be done about this, and something like
> this has been there since forever.  While perhaps some double routines in
> glibc used to be at some point correctly roundded, many others (e.g. float
> or long double) never were, there is always a chance you get different
> results from compile time folding vs. runtime evaluation.

In this case, for its optimizations, GCC shouldn't assume that these results
are equal.