[AArch64] Set COPY ZR isAsCheapAsAMove when needed.
[AArch64] Set COPY ZR isAsCheapAsAMove when needed.

If a subtarget has both ZCZeroing and CustomCheapAsMoveHandling features (now
only Kryo has both), set COPY (W|X)ZR isAsCheapAsAMove.

Differential Revision: http://reviews.llvm.org/D22360

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@275503 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm