Hi Paul,
-fdefault-integer-8 does indeed fix the problem with
rnflow.f90 but breaks tfft2.f90, with a type mismatch at lines 36 and 44.
integer(8), parameter :: jmul = 843314861 ! multiplicateur
integer(8), parameter :: jadd = 453816693 ! constante additive
Does the job and is portable.
I think -frwapv (as suggested by Jakub) would be the better choice.
The problem is the linear congruential pseudo-random number generators
which were much used in earlier times (and are still present in
legacy code), which violate the Fortran standards by assuming silent
truncation.
If a new optimization breaks this (widespread, but illegal) idiom,
maybe the best way to deal with it is to add -frwapv to -std=legacy.
What do you think?
Best regards
Thomas
