[llvm] Use an abbrev to reduce size of VALUE_GUID records in ThinLTO summaries (PR #90497)

[Teresa Johnson via llvm-commits]

https://github.com/teresajohnson approved this pull request.

thanks! out of curiosity, what happens if you try to specify a 64-bit fixed width value?

https://github.com/llvm/llvm-project/pull/90497