[LLVMdev] some superoptimizer results

[John Regehr]

> I guess another way to select interesting transformations could be to look for sequences where the
> result uses a "subset" of the input instruction sequence.

Yeah, I had been noticing those subsets too.  It sounds like it's worth a 
try doing a run that looks only for those.

One nice thing is that if we're just looking for subsets, we will not even 
give the syntehsizer the option to use instructions that aren't in the 
subset -- this should give a nice speedup, and probably will even make 
synthesis more likely to succeed (assuming that an optimization exists 
within the subset).

John