[X86] Add test case to show missed opportunity to shrink a constant index to a gather in order to avoid splitting.
[X86] Add test case to show missed opportunity to shrink a constant index to a gather in order to avoid splitting.

Also add a test case for an index that could be shrunk, but
would create a narrow type. We can go ahead and do it we just
need to be before type legalization.

Similar test cases for scatter as well.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@373290 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm