[flang-commits] [flang] [flang] AliasAnalysis: More formally define and distinguish between data and non-data (PR #91020)

[Joel E. Denny via flang-commits]

================
@@ -50,12 +47,84 @@ struct AliasAnalysis {
   /// Attributes of the memory source object.
   ENUM_CLASS(Attribute, Target, Pointer, IntentIn);
 
+  // See
+  // https://discourse.llvm.org/t/rfc-distinguish-between-data-and-non-data-in-fir-alias-analysis/78759/1
+  //
+  // It is possible, while following the source of a memory reference through
+  // the use-def chain, to arrive at the same origin, even though the starting
+  // points were known to not alias.
+  //
+  // clang-format off
+  // Example:
+  //  ------------------- test.f90 --------------------
+  //  module top
+  //    real, pointer :: a(:)
+  //  end module
+  //  
+  //  subroutine test()
+  //    use top
+  //    a(1) = 1
+  //  -------------------------------------------------
----------------
jdenny-ornl wrote:

```suggestion
  //    a(1) = 1
  //  end subroutine
  //  -------------------------------------------------
```

https://github.com/llvm/llvm-project/pull/91020