[Bug target/86831] three failures in gfortran.fortran-torture with "-Ofast -march=native" on skylake-avx512

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86831

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
"nan_inf_fmt" suggests that the 'fast' part in -Ofast might be the issue.  So
try -O3 -march=native instead?