[Bug fortran/100855] pow run time gfortran vs ifort

[anlauf at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100855

--- Comment #2 from anlauf at gcc dot gnu.org ---
If you do not care about correct rounding, you can replace

   sum = sum + (i ** (0.05 + n))

by

   sum = sum + exp (log (real(i)) * (0.05 + n))

I think __builtin_powf and powf do care.

I do not know if there is a gcc flag that replaces __builtin_powf by the
combination of __builtin_expf / __builtin_logf which would also allow
for (better) vectorization.
(I know of a $$$$ compiler for $$$$ hardware which offers this).