https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79117
--- Comment #1 from Uroš Bizjak <ubizjak at gmail dot com> ---
You can use __builtin_isinf here, so:
if (__builtin_isinf(c)) {
puts("finite");
}
else {
puts("not finite");
}
The expansion of __builtin_isinf performs value truncation automatically when
x87 is involved.
Alternatively, you should use --ffloat-store, or -msse2 -mfpmath=sse.
