[Bug c++/31841] New: warning: 'this.0' is used uninitialized in this function

[Bug c++/31841] New: warning: 'this.0' is used uninitialized in this function

[sylvain dot pion at sophia dot inria dot fr]

Compiling the code below with -O2 -Wall produces the buggy warning
mentionned in the subject.
g++ 4.1 and 4.3 do not have this problem.

The code below is pretty minimal (extracted from CGAL).
For example, removing the derivation from the Empty_class
removes the buggy warning.

----------------
struct Empty_class {};

struct C : Empty_class {};

struct M {
  static C f() { return C(); }
};

struct R {
  C c;

  R() 
    : c(M::f()) {}
};

int main()
{
  R r;
  return 0;
}
--------------------


-- 
           Summary: warning: 'this.0' is used uninitialized in this function
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: sylvain dot pion at sophia dot inria dot fr
  GCC host triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31841

[Bug c++/31841] warning: 'this.0' is used uninitialized in this function

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2007-05-05 19:19 -------
int main() ()
{
  struct Empty_class * this.0;
  struct Empty_class * const this;
  struct C * D.2077;
  struct R r;
  int D.2064;

<bb 2>:
  D.2077_1 = &r.c;
  this.0_3 = this.0_2;
  this.0_4 = (struct Empty_class *) D.2077_1;
  D.2064_5 = 0;
  return D.2064_5;

}

somehow inlining ends up with the unused copies.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31841

[Bug middle-end/31841] [4.2 regression] bogus is used uninitialized (warning in dead code)

[manu at gcc dot gnu dot org]

------- Comment #2 from manu at gcc dot gnu dot org  2009-02-09 16:06 -------
This works in GCC 4.1, 4.3 and 4.4, so this is either a regression (that
probably will not be fixed before 4.2 is closed) or it is not a regression and
should be closed as FIXED already in trunk.


-- 

manu at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |manu at gcc dot gnu dot org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2009-02-09 16:06:14
               date|                            |
            Summary|warning: 'this.0' is used   |[4.2 regression] bogus is
                   |uninitialized in this       |used uninitialized (warning
                   |function (warning in dead   |in dead code)
                   |code)                       |
   Target Milestone|---                         |4.2.6


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31841

[Bug middle-end/31841] [4.2 regression] bogus is used uninitialized (warning in dead code)

[jsm28 at gcc dot gnu dot org]

------- Comment #3 from jsm28 at gcc dot gnu dot org  2009-03-30 21:46 -------
Closing 4.2 branch, fixed in 4.3.


-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
      Known to fail|4.2.3                       |4.2.3 4.2.5
         Resolution|                            |FIXED
   Target Milestone|4.2.6                       |4.3.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31841