[Bug fortran/78290] Gfortran incorrectly creates a copy of an array passed to an array pointer dummy argument

["anlauf at gmx dot de" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78290

Harald Anlauf <anlauf at gmx dot de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |anlauf at gmx dot de

--- Comment #2 from Harald Anlauf <anlauf at gmx dot de> ---
While trying to reduce the reproducer, I encountered a situation where adding
a VOLATILE statement triggers an ICE for the code that is miscompiled:

pr78290a.f90:18:0:

   ip=>ia

internal compiler error: in gfc_add_modify_loc, at fortran/trans.c:159
0x835756e gfc_add_modify_loc(unsigned int, stmtblock_t*, tree_node*,
tree_node*)
        ../../trunk/gcc/fortran/trans.c:158
0x83575e7 gfc_add_modify(stmtblock_t*, tree_node*, tree_node*)
        ../../trunk/gcc/fortran/trans.c:170
0x83a90eb gfc_trans_pointer_assignment(gfc_expr*, gfc_expr*)
        ../../trunk/gcc/fortran/trans-expr.c:8267
0x83a9688 gfc_trans_pointer_assign(gfc_code*)
        ../../trunk/gcc/fortran/trans-expr.c:8054
0x8358357 trans_code
        ../../trunk/gcc/fortran/trans.c:1714
0x838d62c gfc_generate_function_code(gfc_namespace*)
        ../../trunk/gcc/fortran/trans-decl.c:6261
0x830d833 translate_all_program_units
        ../../trunk/gcc/fortran/parse.c:6038
0x830d833 gfc_parse_file()
        ../../trunk/gcc/fortran/parse.c:6238
0x8352db5 gfc_be_parse_file
        ../../trunk/gcc/fortran/f95-lang.c:202

% cat pr78290a.f90
! Wrong code
PROGRAM main
  IMPLICIT NONE
  INTEGER,PARAMETER::KI=4

  TYPE mytype
    INTEGER(KIND=KI)::i=1_KI
  END TYPE mytype

  TYPE(mytype),    DIMENSION(9),TARGET, SAVE::ta
  INTEGER(KIND=KI),DIMENSION(3),TARGET, SAVE::ia    = 3_KI
  INTEGER(KIND=KI),DIMENSION(:),POINTER     ::ia2   =>NULL()
  INTEGER(KIND=KI),DIMENSION(:),POINTER     ::ip    =>NULL()
 volatile::ip
  ALLOCATE(ia2(5)); ia2=2_KI
  ip=>ia
  print*,size(ip)
  CALL sub1(ip)
  print*,size(ip)
  WRITE(*,*)'ia    ',ia
  WRITE(*,*)'ip    ',ip

  ip=>ta%i !!! Works if you comment this line out !!!

! Produces:
! ia               2           2           2
! ip               2           2           2
!
! Should produce:
! ia               3           3           3
! ip               2           2           2           2           2
!
! Seems to be creating a copy of ia and setting argument ipa as a pointer this,
and
! changes to this never get transferred back to ia
! Also does not transfer back change of target or INOUT argugment
! Works if you comment out the line "ip=>ta%i"
!
CONTAINS

  SUBROUTINE sub1(ipa)
    INTEGER(KIND=KI),DIMENSION(:),POINTER::ipa
    ipa => ia2
  END SUBROUTINE sub1

END PROGRAM main