[X86] Use MVT::i8 for scalar shift amounts since that is what they ultimately need to legalize to.
[X86] Use MVT::i8 for scalar shift amounts since that is what they ultimately need to legalize to.

I believe all of these are constants so legalizing them should be pretty trivial, but this saves a step.

In one case it looks like we may have been creating a shift amount larger than the shift input itself.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@336052 91177308-0d34-0410-b5e6-96231b3b80d8

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