[Bug fortran/57991] New: Enhance "Same actual argument associated" warning (-Waliasing)

[Bug fortran/57991] New: Enhance "Same actual argument associated" warning (-Waliasing)

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57991

            Bug ID: 57991
           Summary: Enhance "Same actual argument associated" warning
                    (-Waliasing)
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Keywords: diagnostic
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: burnus at gcc dot gnu.org

gfortran currently warns with -Waliasing for the case:

   Warning: Same actual argument associated with INTENT(IN) argument 'a'
            and INTENT(OUT) argument 'b' at (1)

However, I believe gfortran should also warn if both are INTENT(OUT) -
currently, it doesn't:

      Program q1
        Call test(x, x)
      Contains
        Subroutine test(a,b)
          Integer, intent(out) :: a,b
          a = a*10
          Print *,a,b
        End Subroutine
      End Program

Side remark: The test case is also invalid for other reasons; it's a modified
version of
https://groups.google.com/forum/#!topic/comp.lang.fortran/1ZVmajE1Mjs


See "check_some_aliasing":
          if ((f1_intent == INTENT_IN && f2_intent == INTENT_OUT)
              || (f1_intent == INTENT_OUT && f2_intent == INTENT_IN))



From F2008's "12.5.2.13 Restrictions on entities associated with dummy
arguments"

"(3) Action that a\vects the value of the entity or any subobject of it shall be
taken only through the dummy argument unless
(a) the dummy argument has the POINTER attribute or
(b) the dummy argument has the TARGET attribute, the dummy argument does not
have INTENT(IN), the dummy argument is a scalar object or an assumed-shape
array without the CONTIGUOUS attribute, and the actual argument is a target
other than an array section with a vector subscript."
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From: "paolo.carlini at oracle dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug c++/57101] [4.8/4.9 Regression] -fcompare-debug failure with <type error>
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http://gcc.gnu.org/bugzilla/show_bug.cgi?idW101

--- Comment #3 from Paolo Carlini <paolo.carlini at oracle dot com> ---
This is fixed in mainline. I'm adding the testcase and keeping the bug open
with only the [4.8 Regression] marker.

[Bug fortran/57991] Enhance "Same actual argument associated" warning (-Waliasing)

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57991

--- Comment #1 from Tobias Burnus <burnus at gcc dot gnu.org> ---
Author: burnus
Date: Sat Jul 27 14:17:01 2013
New Revision: 201286

URL: http://gcc.gnu.org/viewcvs?rev=201286&root=gcc&view=rev
Log:
2013-07-27  Tobias Burnus  <burnus@net-b.de>

        PR fortran/57991
        * interface.c (check_some_aliasing): Also warn for intent
        * OUT/OUT.

2013-07-27  Tobias Burnus  <burnus@net-b.de>

        PR fortran/57991
        * gfortran.dg/warn_alias.f90: New.


Added:
    trunk/gcc/testsuite/gfortran.dg/warn_alias.f90
Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/interface.c
    trunk/gcc/testsuite/ChangeLog

[Bug fortran/57991] Enhance "Same actual argument associated" warning (-Waliasing)

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57991

Tobias Burnus <burnus at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |FIXED

--- Comment #2 from Tobias Burnus <burnus at gcc dot gnu.org> ---
FIXED on the trunk (4.9).