[Frontend][OpenMP] Add functions for checking construct type

[kparzysz]

Implement helper functions to identify leaf, composite, and combined constructs.

[llvmbot]

@llvm/pr-subscribers-flang-openmp

Author: Krzysztof Parzyszek (kparzysz)

Changes

Implement helper functions to identify leaf, composite, and combined constructs.

---

Full diff: https://github.com/llvm/llvm-project/pull/87258.diff

3 Files Affected:

• (modified) llvm/include/llvm/Frontend/OpenMP/OMP.h (+4)
• (modified) llvm/lib/Frontend/OpenMP/OMP.cpp (+25)
• (modified) llvm/unittests/Frontend/OpenMPComposeTest.cpp (+26)

diff --git a/llvm/include/llvm/Frontend/OpenMP/OMP.h b/llvm/include/llvm/Frontend/OpenMP/OMP.h
index 4ed47f15dfe59e..ec8ae68f1c2ca0 100644
--- a/llvm/include/llvm/Frontend/OpenMP/OMP.h
+++ b/llvm/include/llvm/Frontend/OpenMP/OMP.h
@@ -20,6 +20,10 @@
 namespace llvm::omp {
 ArrayRef<Directive> getLeafConstructs(Directive D);
 Directive getCompoundConstruct(ArrayRef<Directive> Parts);
+
+bool isLeafConstruct(Directive D);
+bool isCompositeConstruct(Directive D);
+bool isCombinedConstruct(Directive D);
 } // namespace llvm::omp
 
 #endif // LLVM_FRONTEND_OPENMP_OMP_H
diff --git a/llvm/lib/Frontend/OpenMP/OMP.cpp b/llvm/lib/Frontend/OpenMP/OMP.cpp
index dd99d3d074fd1e..98d7c63bb8537e 100644
--- a/llvm/lib/Frontend/OpenMP/OMP.cpp
+++ b/llvm/lib/Frontend/OpenMP/OMP.cpp
@@ -78,4 +78,29 @@ Directive getCompoundConstruct(ArrayRef<Directive> Parts) {
     return Found;
   return OMPD_unknown;
 }
+
+bool isLeafConstruct(Directive D) { return getLeafConstructs(D).empty(); }
+
+bool isCompositeConstruct(Directive D) {
+  // OpenMP Spec 5.2: [17.3, 8-9]
+  // If directive-name-A and directive-name-B both correspond to loop-
+  // associated constructs then directive-name is a composite construct
+  llvm::ArrayRef<Directive> Leafs{getLeafConstructs(D)};
+  if (Leafs.empty())
+    return false;
+  if (getDirectiveAssociation(Leafs.front()) != Association::Loop)
+    return false;
+
+  size_t numLoopConstructs =
+      llvm::count_if(Leafs.drop_front(), [](Directive L) {
+        return getDirectiveAssociation(L) == Association::Loop;
+      });
+  return numLoopConstructs != 0;
+}
+
+bool isCombinedConstruct(Directive D) {
+  // OpenMP Spec 5.2: [17.3, 9-10]
+  // Otherwise directive-name is a combined construct.
+  return !getLeafConstructs(D).empty() && !isCompositeConstruct(D);
+}
 } // namespace llvm::omp
diff --git a/llvm/unittests/Frontend/OpenMPComposeTest.cpp b/llvm/unittests/Frontend/OpenMPComposeTest.cpp
index 29b1be4eb3432c..cc02af8bf67c26 100644
--- a/llvm/unittests/Frontend/OpenMPComposeTest.cpp
+++ b/llvm/unittests/Frontend/OpenMPComposeTest.cpp
@@ -39,3 +39,29 @@ TEST(Composition, GetCompoundConstruct) {
   Directive C7 = getCompoundConstruct({OMPD_parallel_for, OMPD_simd});
   ASSERT_EQ(C7, OMPD_parallel_for_simd);
 }
+
+TEST(Composition, IsLeafConstruct) {
+  ASSERT_TRUE(isLeafConstruct(OMPD_loop));
+  ASSERT_TRUE(isLeafConstruct(OMPD_teams));
+  ASSERT_FALSE(isLeafConstruct(OMPD_for_simd));
+  ASSERT_FALSE(isLeafConstruct(OMPD_distribute_simd));
+}
+
+TEST(Composition, IsCompositeConstruct) {
+  ASSERT_TRUE(isCompositeConstruct(OMPD_distribute_simd));
+  ASSERT_FALSE(isCompositeConstruct(OMPD_for));
+  ASSERT_TRUE(isCompositeConstruct(OMPD_for_simd));
+  // directive-name-A = "parallel", directive-name-B = "for simd",
+  // only directive-name-A is loop-associated, so this is not a
+  // composite construct, even though "for simd" is.
+  ASSERT_FALSE(isCompositeConstruct(OMPD_parallel_for_simd));
+}
+
+TEST(Composition, IsCombinedConstruct) {
+  // "parallel for simd" is a combined construct, see comment in
+  // IsCompositeConstruct.
+  ASSERT_TRUE(isCombinedConstruct(OMPD_parallel_for_simd));
+  ASSERT_FALSE(isCombinedConstruct(OMPD_for_simd));
+  ASSERT_TRUE(isCombinedConstruct(OMPD_parallel_for));
+  ASSERT_FALSE(isCombinedConstruct(OMPD_parallel));
+}

[skatrak]

Thank you, based on the current proposal in #87247 this LGTM. If that changes, this will need another review.

[skatrak]

LGTM, just small comments. Thanks!