Redundant logical operations left after early splitting

[Paolo Bonzini]

>> Is there any particular function or pass that should be dealing with 
>> IOR rx,0 - that I could trace thru and figure out why it does not like 
>> it (or never gets there)?
> I would be looking in combine and simplify-rtx (which is called by
> combine).  If your splitter triggers after combine, then I'm not
> immediately sure where to look -- I'm not offhand aware of a pass
> after combine which would call into simplify-rtx to perform this
> optimization.

Me neither, but this

       if (flag_expensive_optimizations)
         {
           /* Pass pc_rtx so no substitutions are done, just
              simplifications.  */
           if (i1)
             {
               subst_low_luid = DF_INSN_LUID (i1);
               i1src = subst (i1src, pc_rtx, pc_rtx, 0, 0);
             }
           else
             {
               subst_low_luid = DF_INSN_LUID (i2);
               i2src = subst (i2src, pc_rtx, pc_rtx, 0, 0);
             }
         }

could be a place where it is done.

Paolo