[llvm] [BasicAA] Handle wrapping of pointer arithmetic (PR #69116)

[Nikita Popov via llvm-commits]

================
@@ -417,7 +417,8 @@ static LinearExpression GetLinearExpression(
                                 Depth + 1, AC, DT);
         E.Offset <<= RHS.getLimitedValue();
         E.Scale <<= RHS.getLimitedValue();
-        E.IsNSW &= NSW;
+        // The nsw flag has different semantics for shift and mul.
+        E.IsNSW = false;
----------------
nikic wrote:

Well, I guess LHS being a constant isn't relevant in this code, so just checking the RHS is enough.

https://github.com/llvm/llvm-project/pull/69116