Fix an issue in SimplifySetCC() specific to vector comparisons.
Fix an issue in SimplifySetCC() specific to vector comparisons.

When folding X == X we need to check getBooleanContents() to determine if the
result is a vector of ones or a vector of negative ones. 

I tried creating a test case, but the problem seems to only be exposed on a
much older version of clang (around r144500).
rdar://10923049


git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@153966 91177308-0d34-0410-b5e6-96231b3b80d8

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