[llvm] [Frontend][OpenMP] Reduction modifier must be applied somewhere (PR #92160)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-flang-openmp

Author: Krzysztof Parzyszek (kparzysz)

<details>
<summary>Changes</summary>

Detect the case when a reduction modifier ends up not being applied after construct decomposition, treat it as an error.

This fixes a regression in the gfortran test suite after PR90098.

---
Full diff: https://github.com/llvm/llvm-project/pull/92160.diff


1 Files Affected:

- (modified) llvm/include/llvm/Frontend/OpenMP/ConstructDecompositionT.h (+2-1) 


``````````diff
diff --git a/llvm/include/llvm/Frontend/OpenMP/ConstructDecompositionT.h b/llvm/include/llvm/Frontend/OpenMP/ConstructDecompositionT.h
index 5f12c62b832fc..e5fcc493ea590 100644
--- a/llvm/include/llvm/Frontend/OpenMP/ConstructDecompositionT.h
+++ b/llvm/include/llvm/Frontend/OpenMP/ConstructDecompositionT.h
@@ -930,7 +930,8 @@ bool ConstructDecompositionT<C, H>::applyClause(
       // Apply clause without modifier.
       leaf.clauses.push_back(unmodified);
     }
-    applied = true;
+    // The modifier must be applied to some construct.
+    applied = effectiveApplied;
   }
 
   if (!applied)

``````````

</details>


https://github.com/llvm/llvm-project/pull/92160