[compiler-rt] [profile] Fix bounds checks in profile merging (PR #118782)

[Ellis Hoag via llvm-commits]

ellishg wrote:

> > For bound-free arithmetic, shall we cast to uintptr_t, ultimately?
> 
> I'm not sure I get what you mean here -- are you suggesting we should do everything in uintptr rather than const char and then only cast to a pointer type when doing accesses?

I agree with @chapuni, it seems cleaner to make the type of `SrcBitmapStart` (and similar variables) `uintptr_t` in the first place.

https://github.com/llvm/llvm-project/pull/118782