[tablegen] Improve performance on *GenRegisterInfo.inc by replacing SparseVector with BitVector. NFC
[tablegen] Improve performance on *GenRegisterInfo.inc by replacing SparseVector with BitVector. NFC

Summary: Generating X86GenRegisterInfo.inc and AArch64GenRegisterInfo.inc is 8-9% faster on my build.

Reviewers: bogner, javed.absar

Reviewed By: bogner

Subscribers: llvm-commits, kristof.beyls

Differential Revision: https://reviews.llvm.org/D47907

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@334337 91177308-0d34-0410-b5e6-96231b3b80d8

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