Optimize around the fact that pred_iterator is slow: instead of sorting PHI operands by the predecessor order, sort them by the order used by the first PHI in the block. This is still suffucient to expose duplicates.
Optimize around the fact that pred_iterator is slow: instead of sorting
PHI operands by the predecessor order, sort them by the order used by the
first PHI in the block. This is still suffucient to expose duplicates.


git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@85634 91177308-0d34-0410-b5e6-96231b3b80d8

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