https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107874
--- Comment #19 from anlauf at gcc dot gnu.org --- (In reply to john.harper from comment #18) > An interesting problem! But I thought my original test case did not have > recursive I/O because tstuff and fstuff each print something in the > statement > y = merge(tstuff(),fstuff(),x(i)) > but y itself is printed only in the next statement, > print *,y John, your original testcase in comment#0 was fine. I tried to extend it to check for constant as well as non-constant mask, and as you see I made a mistake by trying to make it smaller. Bad idea. > Or does evaluating merge allow each of tstuff and fstuff to be evaluated > at the same time? I was thinking of tstuff and fstuff being evaluated > in succession but could there be systems in which they are evaluated > simultaneously? I don't recall having seen a mentioning in the standard of the order of evaluation of different function (or subroutine) arguments. Do you? (Of course, if side-effects happen during that evaluation, such as I/O, unexpected things may happen.) > If so, whether the program is valid Fortran depends on the > kind of system on which it is being executed. Well, even if the print in tstuff/fstuff were a problem, one could construct other testcases with side-effects that might be conforming.
