[Bug middle-end/30856] missing uninitialized variable warning (CCP)

[manu at gcc dot gnu dot org]

------- Comment #12 from manu at gcc dot gnu dot org  2009-02-07 21:29 -------
This is a duplicate of 18501. CCP assumes y is always 23. 

Reordering passes just changes the set of false negatives/positives. For
example, if you move the warning before CCP, then you get a warning for this
case:

int f(int x)
{
  int y;
  int x = 42;
  if (x == 42) y = 23;
  return y;
}

A more complete analysis is here:

http://gcc.gnu.org/ml/gcc/2005-11/msg00028.html

And some random ideas are here:

http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings#problem_ccp

How other compilers get this right? I don't know, but ideas and patches are
welcome.

*** This bug has been marked as a duplicate of 18501 ***


-- 

manu at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  BugsThisDependsOn|                            |18501
             Status|REOPENED                    |RESOLVED
         Resolution|                            |DUPLICATE


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30856