[clang] [Clang][ByteCode] Store type information inside the custom stack (PR #224903)

[Nikolas Klauser via cfe-commits]

https://github.com/philnik777 commented:

> I guess field reorder changes are to move the padding to the end of the struct?

Yes, exactly.

> ctt: https://llvm-compile-time-tracker.com/compare_clang.php?from=28574f5164166de473098a86f9650a2a6dfee79e&to=420e11c840d9412d54958ae6be72607bf5084214&stat=instructions%3Au&sortBy=interestingness
> 
> The changes to `APFloat.cpp` and `AttrDocTable.cpp` look good, the rest seems like noise or code-size reductions.
> 
> The other changes are here: https://llvm-compile-time-tracker.com/compare.php?from=28574f5164166de473098a86f9650a2a6dfee79e&to=420e11c840d9412d54958ae6be72607bf5084214&stat=instructions:u

I was hoping for a bit more given the slowdown when `ItemTypes` was introduced, but oh well.

https://github.com/llvm/llvm-project/pull/224903