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From: "dominiq at lps dot ens.fr" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug fortran/100855] pow run time gfortran vs ifort
Date: Wed, 02 Jun 2021 16:34:24 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D100855

--- Comment #6 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
On a MacOS, Corei9, 2.4Ghz, the program runs in ~1s, almost indpendtly of t=
he
option level.

This PR remind me an old problem in which the transcendental functions were
almost slower for REAL(4) then for REAL(8) on some Unix distros (Fedora(?),
based of "correct rounding").

What are your timings if you replace

    real :: sum, n, q

with

    real(8) :: sum, n, q

and

            sum =3D sum + (i ** (0.05 + n))

with

            sum =3D sum + (i ** (0.05_8 + n))

?=