https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69225
--- Comment #6 from joseph at codesourcery dot com <joseph at codesourcery dot
com> ---
On Mon, 11 Jan 2016, kyukhin at gcc dot gnu.org wrote:
> BTW, for -std=gnu99 we have EXCESS_PRECISION_FAST engaged.
> This differs from -std=c99
>
> If this correct behavior? I see no mentions of this difference w/ c99 in
> documentation. It only states that gnu99 is "C99 with GNU extensions"
Yes, it's intended and documented. See the documentation for
-fexcess-precision: "By default, @option{-fexcess-precision=fast} is in
effect ... @option{-fexcess-precision=standard} ... is enabled by default
for C if a strict conformance option such as @option{-std=c99} is used".
