https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85599
--- Comment #25 from Thomas Koenig <tkoenig at gcc dot gnu.org> --- (In reply to janus from comment #23) > (In reply to Thomas Koenig from comment #21) > > If we make guarantees that the standard does not, we will be > > creating our own language > > I certainly don't want to create my own language. I'm trying to use the > freedom that the Fortran standard (unfortunately) gives in this area in a > reasonable way. > > > > (and people will get problems moving > > code to another compiler). > > We do have problems with compiler-dependent behavior already. The behavior > I'm proposing is consistent with what ifort, PGI and flang do. But that is something not guaranteed by the standard... > > > Warn, yes. This is the kind of thing that -Wsurprising is for, > > so people will get something with -Wall. (I volunteer for that). > > What do you want to warn about? And how? A front end pass (what else did you expect? :-) If an impure function is found (recursively) in the operands of an .AND. expression, issue a gfc_warning(OPT_Wsurprising, "Impure function %qs at %L may not be evaluated", ...) So, if (flag .and. f(x) > 0.) would also be warned about. > > > Optimize, yes. This could also be integrated with the warning. > > Optimize, yes, but not at the price of changing results. Not against what the standard guarantees. > > Change the language, no. > > Agreed. But that is what you are proposing - we would make a guarantee that the standard does not make.
