[Bug fortran/95647] New: operator(.eq.) and operator(==) treated differently

[longb at cray dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95647

            Bug ID: 95647
           Summary: operator(.eq.) and operator(==) treated differently
           Product: gcc
           Version: 9.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: longb at cray dot com
  Target Milestone: ---

> cat test.f90
     program test
              use, intrinsic :: ieee_arithmetic, only :                 &
     &                ieee_class,                                       &
     &                ieee_class_type,                                  &
     &                ieee_negative_normal,                             &
     &                ieee_positive_normal,                             &
     &                operator(.eq.)

!             use, intrinsic :: ieee_arithmetic

              real(4) r4
              type(ieee_class_type) class1
              r4 = 1.0
              class1 = ieee_class(r4)
              if (class1 .eq. ieee_positive_normal) print *, 'yes'
              r4 = -1.0
              class1 = ieee_class(r4)
              if (class1 .eq. ieee_negative_normal) print *, 'yes'
      end program test



Try test.f90 with 3 compilers:

> ftn test.f90
 ./a.out
yes
yes
> module swap PrgEnv-cray PrgEnv-intel
> ifort test.f90
> ./a.out
yes
yes
> module swap PrgEnv-intel PrgEnv-gnu
> gfortran test.f90
test.f90:6:43:

6 | & ieee_positive_normal, &
1
Error: Intrinsic operator '.eq.' referenced at (1) not found in module
'ieee_arithmetic'
test.f90:13:18:

13 | if (class1 .eq. ieee_positive_normal) print *, 'yes'
1
Error: Operands of comparison operator '.eq.' at (1) are
TYPE(ieee_class_type)/TYPE(ieee_class_type)
test.f90:16:18:

16 | if (class1 .eq. ieee_negative_normal) print *, 'yes'
1
Error: Operands of comparison operator '.eq.' at (1) are
TYPE(ieee_class_type)/TYPE(ieee_class_type)



Alternate test case:



> diff test.f90 test1.f90

7c7

<      &                operator(.eq.)

---

>      &                operator(==)





Works better:

> ftn test1.f90
> ./a.out
yes
yes
> module swap PrgEnv-cray PrgEnv-intel
> ifort test1.f90
> ./a.out
yes
yes
> module swap PrgEnv-intel PrgEnv-gnu
> gfortran test1.f90
> ./a.out
yes
yes



Referencing .eq. or == should have the same effect.

Curiously, the case that works is the one where the USE ONLY clause specifies
operator(==) and the statements that reference that operator are written using
.eq.