[Bug c/52615] New: function pointer casting bug

[Bug c/52615] New: function pointer casting bug

[cglbftm at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52615

             Bug #: 52615
           Summary: function pointer casting bug
    Classification: Unclassified
           Product: gcc
           Version: 4.6.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: cglbftm@gmail.com


gcc compiler can't create any working code for my programm.

Full programm here:

int a(char x)
{
  return x;
}

int main()
{
  float result;

  result = (*(float (*)(double, int, char *))a)(4.5f, 7, "Hello");
  return 0;
}

gcc input:

    gcc main.c

gcc output: 

main.c: In function 'main':
main.c:10:48: warning: function called through a non-compatible type [enabled
by
 default]
main.c:10:48: note: if this code is reached, the program will abort

Compiler create executable file. But it doesn't work.
Other compilers(g++, MSVC 10) works fine. No warnings and working programm.

[Bug c/52615] function pointer casting bug

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52615

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jsm28 at gcc dot gnu.org

--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-03-19 13:20:36 UTC ---
I believe your program invokes undefined behavior.

But, since 4.7 we can DWIM, the middle-end should be able to handle a local
differing call ABI by means of gimple_call_fntype which can be different from
the type of the FUNCTION_DECL we refer to.  I think the only requirement
for the frontends is that the function in the CALL_EXPR is (fntype2 *)&f
with f being of fntype1.

[Bug c/52615] function pointer casting bug

[mpolacek at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52615

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
                 CC|                            |mpolacek at gcc dot gnu.org
         Resolution|---                         |FIXED

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
I'd say fixed by r207300.