[Bug tree-optimization/45734] [4.6 Regression] Devirtualization results in wrong-code

["rguenth at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #2 from rguenth at gcc dot gnu dot org  2010-09-20 15:46 -------
Of course it is ;)  Before pointer-conversions became useless we didn't
propagate the invariant address into the OBJ_TYPE_REF expression.

We still have useful function-pointer conversions as well, because
dropping them would wreck CALL_EXPRs, too (we need to preserve the
original function type, similar to the alias-type on MEM_REFs).
I suppose we could do the same for OBJ_TYPE_REFs that I plan(ned) for
CALL_EXPRs - store the pointed-to type via a MEM_REF - thus a
dereferenced address.

You'd then have

  CALL_EXPR (MEM [fnptr], args ...)
  OBJ_TYPE_REF (MEM [fnptr], MEM [objptr], index)

where both TREE_TYPE of the function and the object are kept like the
FE specified them.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45734