[Bug middle-end/64101] GCC considers that the erf math function does not set errno

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64101

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|                            |x86_64-*-*, mips64-none-elf
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-11-28
     Ever confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
I think the issue is that you don't use the result of erf() and the function
is marked as 'const' - thus does not use ATTR_MATHFN_FPROUNDING_ERRNO.
If you make 'res' global then it will work.