This patch adds support for the vector quadword add/sub instructions introduced

in POWER8:

vadduqm
vaddeuqm
vaddcuq
vaddecuq
vsubuqm
vsubeuqm
vsubcuq
vsubecuq
In addition to adding the instructions themselves, it also adds support for the
v1i128 type for intrinsics (Intrinsics.td, Function.cpp, and
IntrinsicEmitter.cpp).

http://reviews.llvm.org/D9081

llvm-svn: 238144