------- Comment #8 from burnus at gcc dot gnu dot org 2007-02-27 22:04 -------
> > Also isn't -huge()-1 undefined code for Fortran?
> -huge()-1 can be defined in Fortran. [...]
> I'll also note that -pedantic will reject -huge()-1
Just for completeness: In the original example (the very long, incomplete F77
code) the problem was due to an overflow of:
integer :: exponent
! temp very large or +INF
exponent = log10(temp)
Thus as long as such -huge()-1 and (for floating point numbers) INF, NAN and
denormal numbers exists, the intrinsics have to deal with it somehow.
(In reply to comment #4)
> > With example I mean something which actually compiles and runs. Here, I have
> > two problems:
> > include '$(where)/amos/include/essential.ecm'
> > is missing as well as the main program which calls the routine.
>
> I really try to do this, but I am an "old" fortran programer and
> I do not know how to set +Infinity. Yes, of course, I have a case
> that computes it and then hangs, but my code is over 500,000 lines
> long and I did not think it is appropriate.
Well, given that you have 500,000+ lines, it was already quite short and I was
able to reproduce the problem even without the essential.ecm file. (Actually,
reproducing was easier than I initially feared.)
In any case: Thanks for reporting this bug.
[Comparison with 10.0]
> This is not as silly as it sounds. All I care about is to handle
> the special case of 10 (exactly). I have seen cases where the
> equality fails, but the number is really 10.
I'm sure that the two numbers are then not exactly the same (bitwise) though;
nonetheless I'm not good at predicting when an operation will cause an
off-by-one (bit) and when not. I also failed to cook up a small example for
10.0
To create infinity etc. one can simply do:
real :: zero, r
zero = 0.0
r = 1.0/zero ! => +INF
r = zero/zero ! => NaN
r = -1.0/zero ! => -INF
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30981
