[PATCH] Fixup PHI nodes in LowerSwitch

[Marcello Maggioni]

>>! In D4298#27, @pete wrote:
>>>! In D4298#25, @kariddi wrote:
>> Reverted the to the getFirstNonPHI() version waiting for more input on the matter
> 
> Yeah, from what David said I was wrong about this so good to proceed with the original PHI looping code.
> 
> I did take a look in Verifier::visitBasicBlock(BasicBlock &BB) and we don't actually check that PHIs are the first instructions in a BB, or contiguous, but that should be easy to add as David points out its what LangRef says already.

Thanks pete for checking that! I'll keep the getFirstNonPHI() then that should be faster.

http://reviews.llvm.org/D4298