[X86] Don't emit X86::MOV8rr_NOREX from X86InstrInfo::copyPhysReg.
[X86] Don't emit X86::MOV8rr_NOREX from X86InstrInfo::copyPhysReg.

This hook is called after register allocation with two physical registers. We don't need a separate instruction at that time to force register class constraints. I left in the assert though. We also have a fatal error in X86MCCodeEmitter if we ever encode an H-reg and a REX prefix.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@314248 91177308-0d34-0410-b5e6-96231b3b80d8

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