[Bug fortran/95053] New: [11.0 regression] ICE in f951: gfc_divide()

[juergen.reuter at desy dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95053

            Bug ID: 95053
           Summary: [11.0 regression] ICE in f951: gfc_divide()
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: juergen.reuter at desy dot de
  Target Milestone: ---

Created attachment 48507
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48507&action=edit
Reproducer

In some of our legacy code which we are still using, the new gcc/gfortran 11.0
release seems to have introduced a regression which leads to an ICE with the
following message, cf. below. I presume that this regression has been
introduced after the 11.0.0 has been opened, so must be really fresh. 
The file is attached, ist just 250 lines. 
$ gfortran -c mnstin.f 
f951: internal compiler error: gfc_divide(): Bad basic type
0x7fce8b gfc_report_diagnostic
        ../../gcc/fortran/error.c:782
0x7fce8b gfc_internal_error(char const*, ...)
        ../../gcc/fortran/error.c:1402
0x7c4411 gfc_divide(gfc_expr*, gfc_expr*)
        ../../gcc/fortran/arith.c:1831
0x838665 match_add_operand
        ../../gcc/fortran/matchexp.c:394
0x8388c6 match_level_2
        ../../gcc/fortran/matchexp.c:480
0x838aa6 match_level_3
        ../../gcc/fortran/matchexp.c:551
0x838bd8 match_level_4
        ../../gcc/fortran/matchexp.c:599
0x838bd8 match_and_operand
        ../../gcc/fortran/matchexp.c:693
0x838de6 match_or_operand
        ../../gcc/fortran/matchexp.c:722
0x838ee6 match_equiv_operand
        ../../gcc/fortran/matchexp.c:765
0x838fe8 match_level_5
        ../../gcc/fortran/matchexp.c:811
0x8380c2 gfc_match_expr(gfc_expr**)
        ../../gcc/fortran/matchexp.c:870
0x863fda match_actual_arg
        ../../gcc/fortran/primary.c:1662
0x8656a5 gfc_match_actual_arglist(int, gfc_actual_arglist**, bool)
        ../../gcc/fortran/primary.c:1927
0x867ecd gfc_match_rvalue(gfc_expr**)
        ../../gcc/fortran/primary.c:3611
0x8382bf match_primary
        ../../gcc/fortran/matchexp.c:157
0x8382bf match_level_1
        ../../gcc/fortran/matchexp.c:211
0x8382bf match_mult_operand
        ../../gcc/fortran/matchexp.c:267
0x8385fc match_add_operand
        ../../gcc/fortran/matchexp.c:356
0x8388c6 match_level_2
        ../../gcc/fortran/matchexp.c:480