[llvm] [Attributor] Change allocation size and load/store offsets using AAPointerInfo for Alloca instructions (PR #72029)

[Vidush Singhal via llvm-commits]

vidsinghal wrote:

> My comments have suggestions for additional tests. There are also some conceptual questions. We likely want to adjust offsets only late, and deal with inbounds either by not shrinking or by keeping track of them in AAPointerInfo.

Thanks, I will add some more tests. 

I would prefer to deal with inbounds by keeping track of them in AAPointerinfo. 
For each access causing instruction, we can store the full chain of pointers by backtracking. 
Then in AAAllocationinfo, for pointers that are obtained from the allocation being changed we can easily change the inbounds attribute and the type of that GEP by requesting that chain of pointers from AAPointerinfo. 







https://github.com/llvm/llvm-project/pull/72029