[Flang] Incorrect execution result when a pointer variable of the same name is defined for each cray pointer in two dependent modules, and a different array address is defined for each pointer variable

[ohno-fj]

Version of flang : 21.0.0(9fe6f6a0d430b872750354c20f3e4a651bd1f135)/AArch64

In the attached program, a pointer variable of the same name is defined for each cray pointer in two dependent modules (1), and a different array address is defined for each pointer variable (2).
The execution result of such a program is incorrect.
The value of v1 in the main program is expected to be 1.0.

The following are the test program, Flang, Gfortran and ifx compilation/execution result.

sngg752d_2.f90:

module m1
  implicit none
  real::v1
  pointer (ptr,v1)  ! (1)
  real::x(2)
contains
  subroutine s
    implicit none
    x=[1,2]
    ptr=loc(x)  ! (2)
  end subroutine s
end module m1

module m2
  use m1
  implicit none
  private ptr
contains
  subroutine ss
    real::v2,y(2)
    pointer (ptr,v2)  ! (1)
    dimension v2(2)
    y=[11,12]
    ptr=loc(y)  ! (2)  The address assigned to ptr changes from the address of x to the address of y.
    write(6,*) "ss : v1 = ", v1, " v2 = ", v2
  end subroutine ss
end module m2

program main
  use m2
  implicit none
  call s
  call ss
  write(6,*) "main : v1 = ", v1
  print *,'pass'
end program main

$ flang sngg752d_2.f90; ./a.out
 ss : v1 =  11.  v2 =  11. 12.
 main : v1 =  -118116.53
 pass
$

$ gfortran -fcray-pointer sngg752d_2.f90; ./a.out
 ss : v1 =    1.00000000      v2 =    11.0000000       12.0000000
 main : v1 =    1.00000000
 pass
$

$ ifx sngg752d_2.f90; ./a.out
 ss : v1 =    1.000000      v2 =    11.00000       12.00000
 main : v1 =    1.000000
 pass
$

[klausler]

A Cray pointer declaration (pointer(ptr, val)) should create ptr in the current scope rather than use host association. Should be a small change in name resolution.

[llvmbot]

@llvm/issue-subscribers-flang-frontend

Author: None (ohno-fj)

``` Version of flang : 21.0.0(9fe6f6a)/AArch64 ```

In the attached program, a pointer variable of the same name is defined for each cray pointer in two dependent modules (1), and a different array address is defined for each pointer variable (2).
The execution result of such a program is incorrect.
The value of v1 in the main program is expected to be 1.0.

The following are the test program, Flang, Gfortran and ifx compilation/execution result.

sngg752d_2.f90:

module m1
  implicit none
  real::v1
  pointer (ptr,v1)  ! (1)
  real::x(2)
contains
  subroutine s
    implicit none
    x=[1,2]
    ptr=loc(x)  ! (2)
  end subroutine s
end module m1

module m2
  use m1
  implicit none
  private ptr
contains
  subroutine ss
    real::v2,y(2)
    pointer (ptr,v2)  ! (1)
    dimension v2(2)
    y=[11,12]
    ptr=loc(y)  ! (2)  The address assigned to ptr changes from the address of x to the address of y.
    write(6,*) "ss : v1 = ", v1, " v2 = ", v2
  end subroutine ss
end module m2

program main
  use m2
  implicit none
  call s
  call ss
  write(6,*) "main : v1 = ", v1
  print *,'pass'
end program main

$ flang sngg752d_2.f90; ./a.out
 ss : v1 =  11.  v2 =  11. 12.
 main : v1 =  -118116.53
 pass
$

$ gfortran -fcray-pointer sngg752d_2.f90; ./a.out
 ss : v1 =    1.00000000      v2 =    11.0000000       12.0000000
 main : v1 =    1.00000000
 pass
$

$ ifx sngg752d_2.f90; ./a.out
 ss : v1 =    1.000000      v2 =    11.00000       12.00000
 main : v1 =    1.000000
 pass
$