[X86] getTargetShuffleInputs - Control KnownUndef mask element resolution as well as KnownZero.
[X86] getTargetShuffleInputs - Control KnownUndef mask element resolution as well as KnownZero.

We were already controlling whether the KnownZero elements were being written to the target mask, this extends it to the KnownUndef elements as well so we can prevent the target shuffle mask being manipulated at all.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@374732 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm