Pull the creation of the "RewindFunction" function out of the loop. It's only created once, so shouldn't be stuck in the middle of the loop. Also early exit if there are no uses of UnwindInst in the function.
Pull the creation of the "RewindFunction" function out of the loop. It's only
created once, so shouldn't be stuck in the middle of the loop. Also early exit
if there are no uses of UnwindInst in the function.


git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@81785 91177308-0d34-0410-b5e6-96231b3b80d8

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