[Bug tree-optimization/57994] Constant folding of infinity

[vincent-gcc at vinc17 dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57994

--- Comment #22 from Vincent Lefèvre <vincent-gcc at vinc17 dot net> ---
(In reply to Paolo Carlini from comment #20)
> Thus I clearly realize something: if we do better for mpfr, the issue
> remains that if we do *not* optimize and constants are not propagated, we
> issue library calls, which, for command line switches like -fno-math-errno
> -funsafe-math-optimizations give incorrect nan result.

Where does this nan come from? Do you mean that log(0) from the library gives
nan on your machine instead of the correct -inf? For any 0 (as 0 is signed)?
Are you sure that there is really a library call?