Explicitly check for StoreInst, do not lose the chance to delete  unused loads or bitcasts.
Explicitly check for StoreInst, do not lose the chance to delete 
unused loads or bitcasts.


git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@67202 91177308-0d34-0410-b5e6-96231b3b80d8

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