[llvm] [formatv][FmtAlign] Use fill count of type size_t instead of uint32_t (PR #78459)

[Andrei Golubev via llvm-commits]

andrey-golubev wrote:

> > For the record, can you please post the compiler message that you see before this PR? (As well as compiler version)
> 
> aha. this would be rather complicated since I'm not the original author (also, this patch was submitted ~1 year ago if not earlier). to the best of my knowledge, it fails on some MSVC version on x86. i can try to ping whoever brought it up in our downstream originally, maybe they still have something of the kind around.

yeah, no luck. I found the original patch in our fork but the issues were fixed in bulk for MSVC 2019 so there's no special error for this :| from our internal chats I guess it is roughly "conversion from 'size_t' to 'uint32_t' requires a narrowing conversion".

https://github.com/llvm/llvm-project/pull/78459