As there are no instructions left which produce multiple result values, this is a NFC regarding the generated SIL and generated code.
Although this commit is large, most changes are straightforward adoptions to the changes in the ValueBase and SILValue classes.
This is using LLVM's SSAUpdater utility.
I had to abstract it a little further because our 'phi' nodes are slightly
different. The SSAUpdater needs to iterate over phis in a basic block so I
abstracted this in a trait. Therefore, this commit needs a recent version of
puzzle/master which has this change applied.
Swift SVN r19634
