diff --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -1402,7 +1402,10 @@
     return;
   }
 
-  if (Style.isVerilog()) {
+  if (Style.isCpp()) {
+    while (FormatTok->is(tok::l_square) && handleCppAttributes()) {
+    }
+  } else if (Style.isVerilog()) {
     if (Keywords.isVerilogStructuredProcedure(*FormatTok)) {
       parseForOrWhileLoop(/*HasParens=*/false);
       return;
@@ -1638,6 +1641,17 @@
       parseNamespace();
       return;
     }
+    // In Verilog labels can be any expression, so we don't do them here.
+    if (!Style.isVerilog() && Tokens->peekNextToken()->is(tok::colon) &&
+        !Line->MustBeDeclaration) {
+      nextToken();
+      Line->Tokens.begin()->Tok->MustBreakBefore = true;
+      FormatTok->setFinalizedType(TT_GotoLabelColon);
+      parseLabel(!Style.IndentGotoLabels);
+      if (HasLabel)
+        *HasLabel = true;
+      return;
+    }
     // In all other cases, parse the declaration.
     break;
   default:
@@ -1942,16 +1956,6 @@
         return I != E && (++I == E);
       };
       if (OneTokenSoFar()) {
-        // In Verilog labels can be any expression, so we don't do them here.
-        if (!Style.isVerilog() && FormatTok->is(tok::colon) &&
-            !Line->MustBeDeclaration) {
-          Line->Tokens.begin()->Tok->MustBreakBefore = true;
-          FormatTok->setFinalizedType(TT_GotoLabelColon);
-          parseLabel(!Style.IndentGotoLabels);
-          if (HasLabel)
-            *HasLabel = true;
-          return;
-        }
         // Recognize function-like macro usages without trailing semicolon as
         // well as free-standing macros like Q_OBJECT.
         bool FunctionLike = FormatTok->is(tok::l_paren);
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -3023,6 +3023,26 @@
                "  some_other_code();\n"
                "}\n"
                "}");
+  verifyFormat("{\n"
+               "L0:\n"
+               "[[foo]] L1:\n"
+               "[[bar]] [[baz]] L2:\n"
+               "  g();\n"
+               "}");
+  verifyFormat("{\n"
+               "[[foo]] L1: {\n"
+               "[[bar]] [[baz]] L2:\n"
+               "  g();\n"
+               "}\n"
+               "}");
+  verifyFormat("{\n"
+               "[[foo]] L1:\n"
+               "  f();\n"
+               "  {\n"
+               "  [[bar]] [[baz]] L2:\n"
+               "    g();\n"
+               "  }\n"
+               "}");
   FormatStyle Style = getLLVMStyle();
   Style.IndentGotoLabels = false;
   verifyFormat("void f() {\n"
@@ -3046,12 +3066,22 @@
                "  some_code();\n"
                "test_label:;\n"
                "  int i = 0;\n"
-               "}");
+               "}",
+               Style);
   verifyFormat("{\n"
                "  some_code();\n"
                "test_label: { some_other_code(); }\n"
                "}",
                Style);
+  verifyFormat("{\n"
+               "[[foo]] L1:\n"
+               "  f();\n"
+               "  {\n"
+               "[[bar]] [[baz]] L2:\n"
+               "    g();\n"
+               "  }\n"
+               "}",
+               Style);
   // The opening brace may either be on the same unwrapped line as the colon or
   // on a separate one. The formatter should recognize both.
   Style = getLLVMStyle();
@@ -3064,6 +3094,14 @@
                "}\n"
                "}",
                Style);
+  verifyFormat("{\n"
+               "[[foo]] L1:\n"
+               "{\n"
+               "[[bar]] [[baz]] L2:\n"
+               "  g();\n"
+               "}\n"
+               "}",
+               Style);
 }
 
 TEST_F(FormatTest, MultiLineControlStatements) {