Further reduce the number of nodes cloned with getClonedNH, using merge instead. This reduces the number of nodes allocated, then immediately merged and DNE'd from 2193852 to 1298049.  unfortunately this only speeds DSA up by ~1.5s (of 53s), because it's spending most of its time waddling through the scalar map :(
Further reduce the number of nodes cloned with getClonedNH, using merge instead.
This reduces the number of nodes allocated, then immediately merged and DNE'd
from 2193852 to 1298049.  unfortunately this only speeds DSA up by ~1.5s (of
53s), because it's spending most of its time waddling through the scalar map :(


git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@10992 91177308-0d34-0410-b5e6-96231b3b80d8

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