[Bug fortran/38913] Fortran does not set TYPE_CANONICAL properly

[rguenth at gcc dot gnu dot org]

------- Comment #8 from rguenth at gcc dot gnu dot org  2009-06-04 10:55 -------
The whole-file patches now expose this problem.

! { dg-do run }
! Test the fix for PR34438, in which default initializers
! forced the derived type to be static; ie. initialized once
! during the lifetime of the programme.  Instead, they should
! be initialized each time they come into scope.
!
module demo
   type myint
     integer :: bar = 42
   end type myint
end module demo

! ...who came up with this one too.
subroutine func (retval2)
  use demo
  type(myint) :: foo2 = myint (77)
  type(myint) :: retval2
  retval2 = foo2
  foo2%bar = 999
end subroutine func

subroutine other
  use demo
  interface
    subroutine func(rv2)
      use demo
      type(myint) :: rv2
   end subroutine func
  end interface
  type(myint) :: val2
  call func (val2)
  if ((val2%bar .ne. 77_4)) call abort ()

end subroutine other

! Run both tests.
  call other
 end
! { dg-final { cleanup-modules "demo M1" } }


with -O2 -fwhole-file we inline func into other and get

other ()
{
  static struct myint foo2D.1539 = {.barD.1534=77};
  static struct myint foo2D.1539 = {.barD.1534=77};
  struct myint & retval2D.1572;
  struct myint val2D.1544;
  integer(kind=4)D.8 D.1547;

<bb 2>:
  val2D.1544.barD.1542 = 42;
  retval2D.1572_6 = (struct myint &) &val2D.1544;
  *retval2D.1572_6 = foo2D.1539;
  foo2D.1539.barD.1534 = 999;
  D.1547_1 = val2D.1544.barD.1542;
  if (D.1547_1 != 77)

which looks good sofar.  But the store *retval2D.1572_6 = foo2D.1539 is
through a different struct myint than the load from val2D.1544.barD.1542
so we optimize the load to 42 -- the only visible aliasing store.

 <var_decl 0x7ffff7fcbc80 val2
    type <record_type 0x7ffff7fd1180 myint SI
        size <integer_cst 0x7ffff7ed4a50 constant 32>
        unit size <integer_cst 0x7ffff7ed46c0 constant 4>
        align 32 symtab 0 alias set 2 canonical type 0x7ffff7fd1180
        fields <field_decl 0x7ffff7fcbbe0 bar type <integer_type 0x7ffff7ee1540
integer(kind=4)>
            SI file t.f90 line 23 col 0 size <integer_cst 0x7ffff7ed4a50 32>
unit size <integer_cst 0x7ffff7ed46c0 4>
            align 32 offset_align 128
            offset <integer_cst 0x7ffff7ed46f0 constant 0>
            bit offset <integer_cst 0x7ffff7ed4f30 constant 0> context
<record_type 0x7ffff7fd1180 myint>>
        pointer_to_this <pointer_type 0x7ffff7fd1300> chain <type_decl
0x7ffff7fd1240 D.1543>>
    addressable used SI file t.f90 line 30 col 0 size <integer_cst
0x7ffff7ed4a50 32> unit size <integer_cst 0x7ffff7ed46c0 4>
    align 32 context <function_decl 0x7ffff5f3f200 other>>

and

 <indirect_ref 0x7ffff7ff9dc0
    type <record_type 0x7ffff7fced80 myint SI
        size <integer_cst 0x7ffff7ed4a50 constant 32>
        unit size <integer_cst 0x7ffff7ed46c0 constant 4>
        align 32 symtab 0 alias set 4 canonical type 0x7ffff7fced80
        fields <field_decl 0x7ffff7fcbaa0 bar type <integer_type 0x7ffff7ee1540
integer(kind=4)>
            SI file t.f90 line 15 col 0 size <integer_cst 0x7ffff7ed4a50 32>
unit size <integer_cst 0x7ffff7ed46c0 4>
            align 32 offset_align 128
            offset <integer_cst 0x7ffff7ed46f0 constant 0>
            bit offset <integer_cst 0x7ffff7ed4f30 constant 0> context
<record_type 0x7ffff7fced80 myint>>
        reference_to_this <reference_type 0x7ffff7fcef00> chain <type_decl
0x7ffff7fcee40 D.1535>>

    arg 0 <ssa_name 0x7ffff5f4a060
        type <reference_type 0x7ffff7fcef00 type <record_type 0x7ffff7fced80
myint>
            public unsigned DI
            size <integer_cst 0x7ffff7ed4b40 constant 64>
            unit size <integer_cst 0x7ffff7ed4b70 constant 8>
            align 64 symtab 0 alias set -1 canonical type 0x7ffff7fcef00>
        visited var <var_decl 0x7ffff5f46780 retval2>def_stmt retval2_6 =
(struct myint &) &val2;

        version 6
        ptr-info 0x7ffff7f9ac10>>

so the Frontend misses proper type unification.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38913