Hari Limaye ba84cfbe0c [BasicAA] Use nuw attribute of GEPs (#98608) ...

Use the nuw attribute of GEPs to prove that pointers do not alias, in
cases matching the following:

   +                +                     +
   | BaseOffset     |   +<nuw> Indices    |
   ---------------->|-------------------->|
   |-->V2Size       |                     |-------> V1Size
  LHS                                    RHS

If the difference between pointers is Offset +<nuw> Indices then we know
that the addition does not wrap the pointer index type (add nuw) and the
constant Offset is a lower bound on the distance between the pointers. We
can then prove NoAlias via Offset u>= V2Size.

2024-08-20 11:00:03 +01:00

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