Fix PR26543: add a check for definition in CXXRecordDecl.

llvm-svn: 260370
diff --git a/clang/lib/Sema/SemaOpenMP.cpp b/clang/lib/Sema/SemaOpenMP.cpp
index 3ba5daa..9f4daee 100644
--- a/clang/lib/Sema/SemaOpenMP.cpp
+++ b/clang/lib/Sema/SemaOpenMP.cpp
@@ -669,7 +669,8 @@
     if (auto *CTD = CTSD->getSpecializedTemplate())
       RD = CTD->getTemplatedDecl();
   if (IsConstant &&
-      !(SemaRef.getLangOpts().CPlusPlus && RD && RD->hasMutableFields())) {
+      !(SemaRef.getLangOpts().CPlusPlus && RD && RD->hasDefinition() &&
+        RD->hasMutableFields())) {
     // Variables with const-qualified type having no mutable member may be
     // listed in a firstprivate clause, even if they are static data members.
     DSAVarData DVarTemp = hasDSA(D, MatchesAnyClause(OMPC_firstprivate),