rework the Bitstream reader to actually work a machine word at a time, instead of 32-bits at a time. This cuts in half the number of virtual methods called to refill that word when compiling on a 64-bit host, and will make 64-bit read operations faster.
rework the Bitstream reader to actually work a machine word at a time, instead of 32-bits at a time.
This cuts in half the number of virtual methods called to refill that word when compiling on a 64-bit
host, and will make 64-bit read operations faster.


git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@173072 91177308-0d34-0410-b5e6-96231b3b80d8

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