[Patch, Fortran] PR34333 - Handle parameter NAN properly in MAX, MIN, == etc.

[Jerry DeLisle]

Tobias Burnus wrote:
> :ADDPATCH fortran:
> 
> The program (to be compiled with -fno-range-check)
> 
> real, parameter :: nan = 0.0/0.0
> if (nan == nan) call abort()
> print *, max(nan, 4.0) ! shall print "4.0"
> 
> should not abort as  (nan /= nan) shall evaluate as true. This patch
> ensures that comparisons and MIN/MAX work properly for NaN, by using
> mpfr_min and mpfr_max instead of home-grown mpfr_cmp/mpfr_set solutions.
> 
> It additionally replaces mpfr_cmp by mpfr_equal_p etc. which take NaN
> into account. I had to pass the wanted argument to gfc_compare_expr to
> ensure that for  "nan > nan", "nan < nan" and "nan == nan" the result is
> always false.
> 
> Build and regression tested on x86-64-linux.
> OK for the trunk?
> 
> Tobias
> 
> PS: I essentially copied the test case nan_1.f90 and changed the
> variables to parameters.
> 
OK,

Thanks,

Jerry