[flang-commits] [flang] [flang][OpenMP] Add semantic checks for two DECLARE VARIANT restrictions (PR #209528)

[Abid Qadeer via flang-commits]

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@@ -878,6 +878,33 @@ static bool CheckVariantAccessibility(SemanticsContext &context,
   return false;
 }
 
+// Collect the construct selector set of `sel` into `constructs` as an ordered
+// list of leaf construct directives. Combined and composite constructs are
+// decomposed into their leaves (e.g. `target teams` -> target, teams), so two
+// match selectors have the same construct selector set iff the collected lists
+// are equal. An absent construct selector yields an empty list.
+static void CollectConstructSelectorSet(
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abidh wrote:

Yes, structural equality is intended. I went with comparing the normalized selector text (rather than semantically evaluating each property) deliberately, for two reasons:

Simplicity: It avoids per-property logic(e.g. no constant-folding of simdlen expressions, no special-casing inbranch/notinbranch, etc).
Future-proofing: Any construct-selector property added by a future OpenMP version participates in the comparison automatically, with no changes to this check.

https://github.com/llvm/llvm-project/pull/209528