[Bug fortran/40539] Inversion of logical function compiled with ifort not correct.

[burnus at gcc dot gnu dot org]

------- Comment #9 from burnus at gcc dot gnu dot org  2009-06-24 18:11 -------
> > It would be nice to have an option to turn off that fast inversion, at least
> > for compatibility. Or at least to make -O0 case compatible.
> How do other vendor's (Sun, Pathscale, Absoft, etc) represent .true.
> and .false.?  Do we need a compatibility option for each vendor?

Well, I think handling
   "! boolean"  as "! (int) boolean"
is enough, i.e. converting all booleans to integer as C has for integers the
concept of nonzero = true and zero = false - thus NOT(nonzero) is alway zero
(all bits). I think one can consider such an option, but I am not really happy
about such a solution - and I think (fear?) others will (strongly) oppose such
an option.

Regarding the rhetoric question: NAG f95, sunf95 and g95 use 1 and 0; using
ifort + Intel's icc, open64's opencc, Sun's suncc, however, gives FALSE for
when using NOT ("!") on the result of the Fortran function call. (With GCC it
gives TRUE.)


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40539