[Bug middle-end/31279] Uninitialized warning for call-by-reference arguments with known intent(in)

[Bug middle-end/31279] Uninitialized warning for call-by-reference arguments with known intent(in)

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31279

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-02-02
     Ever Confirmed|0                           |1

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-02-02 17:49:32 UTC ---
Confirmed.

[Bug middle-end/31279] Uninitialized warning for call-by-reference arguments with known intent(in)

[dominiq at lps dot ens.fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31279

--- Comment #2 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
Still no warning at revision 200371.

[Bug middle-end/31279] Uninitialized warning for call-by-reference arguments with known intent(in)

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31279

Bug 31279 depends on bug 31094, which changed state.

Bug 31094 Summary: Support annotating function parameters as read-only and/or non-escaping
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31094

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

[Bug middle-end/31279] Uninitialized warning for call-by-reference arguments with known intent(in)

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=31279

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=10138

--- Comment #6 from Martin Sebor <msebor at gcc dot gnu.org> ---
In conjunction with attribute access (read_only) (which I presume is the moral
equivalent of INTENT(IN)), the patch I submitted for pr10138 puts in place the
infrastructure to implement this warning for FORTRAN as well.  All that it
should need is mapping INTENT(IN) to the attribute.

https://gcc.gnu.org/pipermail/gcc-patches/2020-May/545856.html

[Bug fortran/31279] Uninitialized warning for call-by-reference arguments with known intent(in)

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=31279

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|middle-end                  |fortran

--- Comment #7 from Martin Sebor <msebor at gcc dot gnu.org> ---
GCC added the attributes mentioned in comment #4 under the name access -- see
below.  Getting the middle end to issue a warning for the cases described in
comment #0 should be a matter of the Fortran front end making use of the
attribute.

$ cat x.c && gcc -S -Wall x.c
__attribute__ ((access (read_only, 1))) void f (int*);

void g (void)
{
  int x;
  f (&x);
}
x.c: In function ‘g’:
x.c:6:3: warning: ‘x’ is used uninitialized [-Wuninitialized]
    6 |   f (&x);
      |   ^~~~~~
x.c:1:46: note: in a call to ‘f’ declared with attribute ‘access (read_only,
1)’ here
    1 | __attribute__ ((access (read_only, 1))) void f (int*);
      |                                              ^
x.c:5:7: note: ‘x’ declared here
    5 |   int x;
      |       ^

[Bug fortran/31279] Uninitialized warning for call-by-reference arguments with known intent(in)

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=31279

--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
The original testcase hides everything behind array descriptors, even with
unrolling and vectorization disabled we end up with

  <bb 2> [local count: 214748368]:
  parm.0.data = &alist[0];
  parm.0.offset = -1;
  parm.0.dtype.elem_len = 4;
  MEM <unsigned long> [(void *)&parm.0 + 24B] = 1103806595072;
  parm.0.span = 4;
  parm.0.dim[0].stride = 1;
  parm.0.dim[0].lbound = 1;
  parm.0.dim[0].ubound = 4;
  atmp.1.data = &A.2;
  atmp.1.offset = 0;
  atmp.1.dtype.elem_len = 4;
  MEM <unsigned long> [(void *)&atmp.1 + 24B] = 1103806595072;
  atmp.1.span = 4;
  atmp.1.dim[0].stride = 1;
  atmp.1.dim[0].lbound = 0;
  atmp.1.dim[0].ubound = 3;
  _gfortran_cshift0_4 (&atmp.1, &parm.0, &C.4234, 0B);

the frontend might set the fnspec correctly to r (read-only, even transitively)
which we might use here but then the actual use is the intrinsic and the
fnspec does not say that the function acrually reads from the uninitialized
storage.

[Bug middle-end/31279] New: Uninitialized warning for call-by-reference arguments with known intent(in)

[burnus at gcc dot gnu dot org]

In Fortran one can specify the intent of variables thus if all arguments have
INTENT(IN) then GCC should be able to detect that alist in the call to cshift
is uninitialized.

This depends on the middle end support of intents (PR31094) plus using these in
gfortran.

Example (using an intrinsic function):

program testcshft
  integer :: alist(4)
  alist =cshift(alist,-1)
  write(*,*) alist
end program testcshft


-- 
           Summary: Uninitialized warning for call-by-reference arguments
                    with known intent(in)
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Keywords: diagnostic
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: burnus at gcc dot gnu dot org
 BugsThisDependsOn: 31094


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31279

[Bug middle-end/31279] Uninitialized warning for call-by-reference arguments with known intent(in)

[burnus at gcc dot gnu dot org]

-- 

burnus at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |enhancement


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31279