aliasing question

[Jan Hubicka]

Hi,
while looking into releasing more SSA_NAMEs I run across following code
(in combining combine.i with -O2 on i686).
ssa dump says:

  #   V_MUST_DEF <value_49>;
  value = T.4862_48;

and alias1 dump:

  #   value_229 = V_MAY_DEF <value_19>;
  value = T.4862_48;

Why the MUST_DEF is getting converted to MAY_DEF in such a obvious case
for MUST_DEF?

I will keep copy of the dumps around in the case you are interested to
look into it.  It is one of places (actually first nontrivial) where we
are leakign SSA_NAME unfreeed.

Honza