[Bug middle-end/78977] [7 Regression] g++7 snprintf() of double produces wrong code with -O3

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78977

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Hannes Hauswedell from comment #3)
> > if it does, then we really need self-contained small test.
> 
> Like I said, it doesn't happen on all the time and I have had difficulties
> extracting it. I could make something smaller than our whole repo, but it
> would likely still be quite a lot of code. Or is there some way I can make
> GCC dump an intermediate version of all the code that it actually uses for
> building the binary?

We can reduce it ourselves, if you provide preprocessed source for the
compilation unit in which it happens, plus g++ command line options.
But without access to FreeBSD we also need to know what the double argument is
(unless it is a compile time constant) and what FreeBSD snprintf prints (unless
it is the "0.3\000\377\177\000\000" you mentioned earlier).