https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42108
--- Comment #66 from Salvatore Filippone <sfilippone at uniroma2 dot it> --- As far as I remember(In reply to rguent...@suse.de from comment #65) > On Wed, 10 Dec 2014, burnus at gcc dot gnu.org wrote: > > > Fortran 66 compilers did. For instance, "DO i = 2, 1" would then be executed > > once. (Such loops are not permitted in F66 - and some compilers executed > > them > > once others zero times; since F77, such loops are permitted and executed > > zero > > times. Unsurprisingly, some old code from the 60s relies on the execute once > > feature.) > > > > g77 and some commercial compilers have a compile flag like "-f66", gfortran > > hasn't and I don't think it ever will.] > > I wondered if > > DO i = 1, 1, 0 > > is valid (a step of zero). Note that DO i = 2, 1 wouldn't be executed > once with the current generated code, only DO i = 1, 1 is, but with > step == 0 it would divide by zero. Step 0 is not allowed (see e.g. F2003 Handbook, sect. 8.7.2.1.1). Salvatore
