[flang-commits] [flang] [flang][OpenMP] Lower DO and SIMD variants in metadirectives (PR #210810)

[via flang-commits]

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@@ -1336,6 +1336,16 @@ void OmpStructureChecker::Leave(const parser::OpenMPConstruct &x) {
 }
 
 void OmpStructureChecker::Enter(const parser::OpenMPDeclarativeConstruct &x) {
+  std::size_t firstVariant{metadirectiveVariantScopeStarts_.empty()
+          ? 0
+          : metadirectiveVariantScopeStarts_.back()};
+  if (firstVariant < metadirectiveLoopVariants_.size()) {
+    // An OpenMP declarative directive between a loop-associated
+    // metadirective and a DO construct in the same scope interrupts their
+    // association. Preserve pending variants from enclosing scopes.
+    CheckMetadirectiveVariantsWithoutLoop(firstVariant);
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MattPD wrote:

`CheckMetadirectiveVariantsWithoutLoop` matches only `OpenMPDeclarativeConstruct` nodes, but `spliceAssociatedDoEval` skips only end statements and `CompilerDirective`, and the OpenACC declarative forms are PFT directives too.

With `-fopenacc -fopenmp`, an `!$acc declare create(x)` or `!$acc routine seq` between the metadirective and its DO passes `-fsyntax-only` with no diagnostic and then reaches `not yet implemented: loop-associated METADIRECTIVE without associated DO`. Removing just the `!$acc` line lowers cleanly.

Would it be worth deriving the `spliceAssociatedDoEval` skip list and this check from one shared predicate, so the two cannot drift?

https://github.com/llvm/llvm-project/pull/210810