1 files changed, 5 insertions, 0 deletions
diff --git a/clang/lib/Sema/Sema.cpp b/clang/lib/Sema/Sema.cpp
index c0997688b2d..aa4f6461b65 100644
--- a/clang/lib/Sema/Sema.cpp
+++ b/clang/lib/Sema/Sema.cpp
@@ -653,6 +653,11 @@ void Sema::getUndefinedButUsed(
           !isExternalWithNoLinkageType(VD) &&
           !VD->getMostRecentDecl()->isInline())
         continue;
+
+      // Skip VarDecls that lack formal definitions but which we know are in
+      // fact defined somewhere.
+      if (VD->isKnownToBeDefined())
+        continue;
     }
 
     Undefined.push_back(std::make_pair(ND, UndefinedUse.second));