Slightly change TableGen's definition of a register subclass.
Slightly change TableGen's definition of a register subclass.

A subclass is allowed to have a larger spill size than the superclass, and the
spill alignment must be a multiple of the superclass alignment. This causes
the following new subclass relations:

=== Alpha ===
F4RC -> F8RC

=== PPC ===
F4RC -> F8RC

=== SPU ===
R8C -> R16C -> R32C/R32FP -> R64C/R64FP -> GPRC/VECREG

=== X86 ===
FR32  -> FR64  -> VR128
RFP32 -> RFP64 -> RFP80

These subclass relations are consistent with the behaviour of -join-cross-class-copies.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@70511 91177308-0d34-0410-b5e6-96231b3b80d8

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