[Bug c/79117] __builtin_isfinite edge case incorrect on i386

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79117

--- Comment #4 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Julian Taylor from comment #3)
> using isinf is not correct as isinf(nan) == 0
> why does isinf do the truncation on x87 and isfinite does not?

Because isinf is expanded in a target-dependent part and isfinite in a generic
part of the compiler.