Redundant logical operations left after early splitting

[Paolo Bonzini]

> This  would indicate that simplify-rtx inside fwprop is removing OR Rx,0
> but not picking up the the additionally revealed forward propagation 
> oppertunities
> This would seem to be an avoidable limitation.

Yes, can you send me your MD patch and a simple testcase?  fwprop is 
supposed to be "cascading", and some bugs in cascading were already 
revealed by the AVR port.

It might be even more worthwhile to try *moving* fwprop2 after combine, 
then.

Paolo