3 files changed, 10 insertions, 2 deletions
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 51b5ae91d6a..0b3e60f82a8 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -5028,8 +5028,11 @@ Decl *Sema::ActOnFinishFunctionBody(Decl *dcl, Stmt *Body,
     // Verify that we have no forward references left.  If so, there was a goto
     // or address of a label taken, but no definition of it.  Label fwd
     // definitions are indicated with a null substmt.
-    if (L->getSubStmt() != 0)
+    if (L->getSubStmt() != 0) {
+      if (!L->isUsed())
+        Diag(L->getIdentLoc(), diag::warn_unused_label) << L->getName();
       continue;
+    }
 
     // Emit error.
     Diag(L->getIdentLoc(), diag::err_undeclared_label_use) << L->getName();
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 4bd596b6728..40009844482 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -6871,6 +6871,7 @@ ExprResult Sema::ActOnAddrLabel(SourceLocation OpLoc,
   if (LabelDecl == 0)
     LabelDecl = new (Context) LabelStmt(LabLoc, LabelII, 0);
 
+  LabelDecl->setUsed();
   // Create the AST node.  The address of a label always has type 'void*'.
   return Owned(new (Context) AddrLabelExpr(OpLoc, LabLoc, LabelDecl,
                                        Context.getPointerType(Context.VoidTy)));
@@ -7355,8 +7356,11 @@ ExprResult Sema::ActOnBlockStmtExpr(SourceLocation CaretLoc,
 
     // Verify that we have no forward references left.  If so, there was a goto
     // or address of a label taken, but no definition of it.
-    if (L->getSubStmt() != 0)
+    if (L->getSubStmt() != 0) {
+      if (!L->isUsed())
+        Diag(L->getIdentLoc(), diag::warn_unused_label) << L->getName();
       continue;
+    }
 
     // Emit error.
     Diag(L->getIdentLoc(), diag::err_undeclared_label_use) << L->getName();
diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index 47ea4f2c253..24489544e06 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -994,6 +994,7 @@ Sema::ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc,
   if (LabelDecl == 0)
     LabelDecl = new (Context) LabelStmt(LabelLoc, LabelII, 0);
 
+  LabelDecl->setUsed();
   return Owned(new (Context) GotoStmt(LabelDecl, GotoLoc, LabelLoc));
 }