1 files changed, 32 insertions, 1 deletions
diff --git a/clang/lib/Sema/SemaOpenMP.cpp b/clang/lib/Sema/SemaOpenMP.cpp
index b51f25c..1556f6e 100644
--- a/clang/lib/Sema/SemaOpenMP.cpp
+++ b/clang/lib/Sema/SemaOpenMP.cpp
@@ -12708,9 +12708,11 @@ StmtResult Sema::ActOnOpenMPAtomicDirective(ArrayRef<OMPClause *> Clauses,
       }
       break;
     }
+    case OMPC_weak:
     case OMPC_fail: {
       if (!EncounteredAtomicKinds.contains(OMPC_compare)) {
-        Diag(C->getBeginLoc(), diag::err_omp_atomic_fail_no_compare)
+        Diag(C->getBeginLoc(), diag::err_omp_atomic_no_compare)
+            << getOpenMPClauseName(C->getClauseKind())
             << SourceRange(C->getBeginLoc(), C->getEndLoc());
         return StmtError();
       }
@@ -13202,6 +13204,27 @@ StmtResult Sema::ActOnOpenMPAtomicDirective(ArrayRef<OMPClause *> Clauses,
       E = Checker.getE();
       D = Checker.getD();
       CE = Checker.getCond();
+      // The weak clause may only appear if the resulting atomic operation is
+      // an atomic conditional update for which the comparison tests for
+      // equality. It was not possible to do this check in
+      // OpenMPAtomicCompareChecker::checkStmt() as the check for OMPC_weak
+      // could not be performed (Clauses are not available).
+      auto *It = find_if(Clauses, [](OMPClause *C) {
+        return C->getClauseKind() == llvm::omp::Clause::OMPC_weak;
+      });
+      if (It != Clauses.end()) {
+        auto *Cond = dyn_cast<BinaryOperator>(CE);
+        if (Cond->getOpcode() != BO_EQ) {
+          ErrorInfo.Error = Checker.ErrorTy::NotAnAssignment;
+          ErrorInfo.ErrorLoc = Cond->getExprLoc();
+          ErrorInfo.NoteLoc = Cond->getOperatorLoc();
+          ErrorInfo.ErrorRange = ErrorInfo.NoteRange = Cond->getSourceRange();
+
+          Diag(ErrorInfo.ErrorLoc, diag::err_omp_atomic_weak_no_equality)
+              << ErrorInfo.ErrorRange;
+          return StmtError();
+        }
+      }
       // We reuse IsXLHSInRHSPart to tell if it is in the form 'x ordop expr'.
       IsXLHSInRHSPart = Checker.isXBinopExpr();
     }
@@ -17593,6 +17616,9 @@ OMPClause *Sema::ActOnOpenMPClause(OpenMPClauseKind Kind,
   case OMPC_relaxed:
     Res = ActOnOpenMPRelaxedClause(StartLoc, EndLoc);
     break;
+  case OMPC_weak:
+    Res = ActOnOpenMPWeakClause(StartLoc, EndLoc);
+    break;
   case OMPC_threads:
     Res = ActOnOpenMPThreadsClause(StartLoc, EndLoc);
     break;
@@ -17781,6 +17807,11 @@ OMPClause *Sema::ActOnOpenMPRelaxedClause(SourceLocation StartLoc,
   return new (Context) OMPRelaxedClause(StartLoc, EndLoc);
 }
 
+OMPClause *Sema::ActOnOpenMPWeakClause(SourceLocation StartLoc,
+                                       SourceLocation EndLoc) {
+  return new (Context) OMPWeakClause(StartLoc, EndLoc);
+}
+
 OMPClause *Sema::ActOnOpenMPThreadsClause(SourceLocation StartLoc,
                                           SourceLocation EndLoc) {
   return new (Context) OMPThreadsClause(StartLoc, EndLoc);