[llvm] [Coverage] ProfileData: Handle MC/DC Bitmap as BitVector. NFC. (PR #80608)

[Jessica Paquette via llvm-commits]

ornata wrote:

Cool, this looks a lot cleaner.

Are there performance improvements as a result of this change?

> The BitVector container provides a dynamic size set of bits for manipulation. It supports individual bit setting/testing, as well as set operations. The set operations take time O(size of bitvector), but operations are performed one word at a time, instead of one bit at a time. This makes the BitVector very fast for set operations compared to other containers. Use the BitVector when you expect the number of set bits to be high (i.e. a dense set).
(https://llvm.org/docs/ProgrammersManual.html#bitvector)

If there are, it would be nice to include them in the commit message.

https://github.com/llvm/llvm-project/pull/80608