[llvm] [Loads] Check loop-varying pointer in isDereferenceableAndAlignedInLoop. (PR #120962)

[Philip Reames via llvm-commits]

preames wrote:

I'm missing something here.  Why does knowing something is dereferenceable at the end of the header tell us anything about it's dereferenceability across the whole loop?  What if the header contains e.g. a throwing call?

https://github.com/llvm/llvm-project/pull/120962