[Bug tree-optimization/39799] [4.3/4.4/4.5 Regression] missing 'may be used uninitialized' warning

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2009-04-17 20:55 -------
This is because we zero-initialize uninitialized variables during inlining.
Honza, do you remember why we do this?

          /* By inlining function having uninitialized variable, we might
             extend the lifetime (variable might get reused).  This cause
             ICE in the case we end up extending lifetime of SSA name across
             abnormal edge, but also increase register pressure.

             We simply initialize all uninitialized vars by 0 except
             for case we are inlining to very first BB.  We can avoid
             this for all BBs that are not inside strongly connected
             regions of the CFG, but this is expensive to test.  */


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hubicka at gcc dot gnu dot
                   |                            |org
             Status|UNCONFIRMED                 |NEW
          Component|regression                  |tree-optimization
     Ever Confirmed|0                           |1
           Keywords|                            |diagnostic
   Last reconfirmed|0000-00-00 00:00:00         |2009-04-17 20:55:52
               date|                            |
            Summary|missing 'may be used        |[4.3/4.4/4.5 Regression]
                   |uninitialized' warning      |missing 'may be used
                   |                            |uninitialized' warning
   Target Milestone|---                         |4.3.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39799