[GVN] Split AvailableValueInBlock into two parts [NFC]
[GVN] Split AvailableValueInBlock into two parts [NFC]

AvailableValue is the part that represents the potential rematerialization.  AvailableValueInBlock is simply a pair of an AvailableValue and a BB which we might materialize it in.

This is motivated by http://reviews.llvm.org/D16608.  The intent is that we'll have a single function which handles the local case which both local and non-local will use to identify available values.  Once that's done, the local case can rematerialize at the use site and the non-local case can do the SSA construction as it does currently.



git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@258882 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm