Unify the interface of the three mask+shift transform helpers, and factor the differences that were hiding in one of them into its other caller, the SRL handling code. No change in behavior.
Unify the interface of the three mask+shift transform helpers, and
factor the differences that were hiding in one of them into its other
caller, the SRL handling code. No change in behavior.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@147940 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/llvm,dslab-epfl/asap,apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,chubbymaggie/asap,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,chubbymaggie/asap,llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,chubbymaggie/asap,GPUOpen-Drivers/llvm,dslab-epfl/asap,GPUOpen-Drivers/llvm,chubbymaggie/asap,apple/swift-llvm,dslab-epfl/asap,dslab-epfl/asap,apple/swift-llvm,chubbymaggie/asap,dslab-epfl/asap,apple/swift-llvm,dslab-epfl/asap,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,chubbymaggie/asap,dslab-epfl/asap,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm