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From: "dreier at dkrz dot de" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug fortran/107968] New: array slicing gives wrong result for an array pointer defined in a subroutine Date: Mon, 05 Dec 2022 07:16:21 +0000 [thread overview] Message-ID: <bug-107968-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107968 Bug ID: 107968 Summary: array slicing gives wrong result for an array pointer defined in a subroutine Product: gcc Version: 12.2.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: fortran Assignee: unassigned at gcc dot gnu.org Reporter: dreier at dkrz dot de Target Milestone: --- Created attachment 54010 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54010&action=edit source code The following code show some weird behavior to me: ``` PROGRAM foo implicit none TYPE t_geographical_coordinates REAL :: lon REAL :: lat END TYPE t_geographical_coordinates TYPE t_vertices REAL, POINTER :: vlon(:) => null() REAL, POINTER :: vlat(:) => null() END TYPE t_vertices TYPE(t_vertices), POINTER :: vertices_pointer TYPE(t_vertices), TARGET :: vertices_target TYPE(t_geographical_coordinates), ALLOCATABLE, TARGET :: vertex(:) ! initialization ALLOCATE(vertex(2)) vertex%lon = 1 vertex%lat = 2 ! obtain pointer to (non-contiguous) field vertices_target%vlon => vertex%lon ! set pointer in a subroutine CALL set_vertices_pointer(vertices_target) WRITE (0,*) vertices_pointer%vlon WRITE (0,*) vertices_pointer%vlon(1:) ! It seems that setting the pointer in a subroutine does something else than ! setting it directly. Furthermore uncommenting the following line fixes the ! issue but changes the output of the lines above ?! ! vertices_pointer => vertices_target CONTAINS SUBROUTINE set_vertices_pointer(vertices) TYPE(t_vertices), POINTER, INTENT(IN) :: vertices vertices_pointer => vertices END SUBROUTINE set_vertices_pointer END PROGRAM foo ``` I expect the output to be: ``` 1.00000000 1.00000000 1.00000000 1.00000000 ``` Instead, the compiled program gives me ``` 1.00000000 1.00000000 1.00000000 2.00000000 ``` Compiled with gfortran 12.2 on Ubuntu 22.10. No warnings with `-Wall -Wextra`. Same behavior with `-fno-strict-aliasing -fwrapv`.
next reply other threads:[~2022-12-05 7:16 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-12-05 7:16 dreier at dkrz dot de [this message] 2022-12-05 19:12 ` [Bug fortran/107968] " anlauf at gcc dot gnu.org 2022-12-05 21:36 ` anlauf at gcc dot gnu.org
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