[Bug fortran/51638] gfortran optimization breaks a single variable used as both input and output for subroutine call

[bardeau at iram dot fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51638

--- Comment #12 from Sebastien Bardeau <bardeau at iram dot fr> 2012-01-09 09:23:41 UTC ---
Dear Tobias,

many thanks for your help and for the many alternatives you gave us. We are
still discussing which one is the best to choose in our context, but at least
we have several solutions to this problem.

A final word: in the new version of the attached program (which also fails with
optimization) I removed as much invalid statements as I could. Only the
"12.4.1.7 restrictions" are still broken, of course. I am surprised to see that
none of the compilers I tested (gfortran, ifort, g95) complain about the fact
that the same variable is used as both intent(in) and intent(out) variable.
Shouldn't it be at least a warning?

And yes, this bug ticket can be closed...