[clang] [llvm] [LLVM][IRBuilder] Use NUW arithmetic for Create{ElementCount,TypeSize}. (PR #143532)

[Graham Hunter via llvm-commits]

https://github.com/huntergr-arm approved this pull request.

LGTM; I do think it's worth documenting the assumption/requirement about a sufficiently large type in the comments on the declarations for CreateElementCount and CreateTypeSize.

https://github.com/llvm/llvm-project/pull/143532