diff --git a/clang/lib/Format/FormatToken.h b/clang/lib/Format/FormatToken.h
index dd7e991342715..ea3bbe368d5b0 100644
--- a/clang/lib/Format/FormatToken.h
+++ b/clang/lib/Format/FormatToken.h
@@ -396,6 +396,21 @@ struct FormatToken {
     }
   }
 
+  /// \brief Returns \c true if this is a string literal that's like a label,
+  /// e.g. ends with "=" or ":".
+  bool isLabelString() const {
+    if (!is(tok::string_literal))
+      return false;
+    StringRef Content = TokenText;
+    if (Content.startswith("\"") || Content.startswith("'"))
+      Content = Content.drop_front(1);
+    if (Content.endswith("\"") || Content.endswith("'"))
+      Content = Content.drop_back(1);
+    Content = Content.trim();
+    return Content.size() > 1 &&
+           (Content.back() == ':' || Content.back() == '=');
+  }
+
   /// \brief Returns actual token start location without leading escaped
   /// newlines and whitespace.
   ///
diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index 4db0e937afc03..77b6a5d4d26bb 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -1882,8 +1882,7 @@ unsigned TokenAnnotator::splitPenalty(const AnnotatedLine &Line,
       return 100;
   }
 
-  if (Left.is(tok::comma) || (Right.is(tok::identifier) && Right.Next &&
-                              Right.Next->is(TT_DictLiteral)))
+  if (Right.is(tok::identifier) && Right.Next && Right.Next->is(TT_DictLiteral))
     return 1;
   if (Right.is(tok::l_square)) {
     if (Style.Language == FormatStyle::LK_Proto)
@@ -1999,21 +1998,17 @@ unsigned TokenAnnotator::splitPenalty(const AnnotatedLine &Line,
   if (Left.is(TT_JavaAnnotation))
     return 50;
 
-  if (Right.is(tok::lessless)) {
-    if (Left.is(tok::string_literal) &&
-        (Right.NextOperator || Right.OperatorIndex != 1)) {
-      StringRef Content = Left.TokenText;
-      if (Content.startswith("\""))
-        Content = Content.drop_front(1);
-      if (Content.endswith("\""))
-        Content = Content.drop_back(1);
-      Content = Content.trim();
-      if (Content.size() > 1 &&
-          (Content.back() == ':' || Content.back() == '='))
-        return 25;
-    }
+  if (Left.isOneOf(tok::plus, tok::comma) && Left.Previous &&
+      Left.Previous->isLabelString() &&
+      (Left.NextOperator || Left.OperatorIndex != 1))
+    return 100;
+  if (Left.is(tok::comma))
+    return 1;
+  if (Right.isOneOf(tok::lessless, tok::plus) && Left.isLabelString() &&
+      (Right.NextOperator || Right.OperatorIndex != 1))
+    return 25;
+  if (Right.is(tok::lessless))
     return 1; // Breaking at a << is really cheap.
-  }
   if (Left.is(TT_ConditionalExpr))
     return prec::Conditional;
   prec::Level Level = Left.getPrecedence();
@@ -2631,7 +2626,8 @@ void TokenAnnotator::printDebugInfo(const AnnotatedLine &Line) {
                  << " FakeLParens=";
     for (unsigned i = 0, e = Tok->FakeLParens.size(); i != e; ++i)
       llvm::errs() << Tok->FakeLParens[i] << "/";
-    llvm::errs() << " FakeRParens=" << Tok->FakeRParens << "\n";
+    llvm::errs() << " FakeRParens=" << Tok->FakeRParens;
+    llvm::errs() << " Text='" << Tok->TokenText << "'\n";
     if (!Tok->Next)
       assert(Tok == Line.Last);
     Tok = Tok->Next;
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 5bed7a81de190..adf529cfedacd 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -5109,29 +5109,6 @@ TEST_F(FormatTest, AlignsPipes) {
       "llvm::errs() << aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(\n"
       "    aaaaaaaaaaaaaaaaaaaaaaaaaaaa, aaaaaaaaaaaaaaaaaaaaaaaaaaaa);");
 
-  verifyFormat("return out << \"somepacket = {\\n\"\n"
-               "           << \" aaaaaa = \" << pkt.aaaaaa << \"\\n\"\n"
-               "           << \" bbbb = \" << pkt.bbbb << \"\\n\"\n"
-               "           << \" cccccc = \" << pkt.cccccc << \"\\n\"\n"
-               "           << \" ddd = [\" << pkt.ddd << \"]\\n\"\n"
-               "           << \"}\";");
-
-  verifyFormat("llvm::outs() << \"aaaaaaaaaaaaaaaa: \" << aaaaaaaaaaaaaaaa\n"
-               "             << \"aaaaaaaaaaaaaaaa: \" << aaaaaaaaaaaaaaaa\n"
-               "             << \"aaaaaaaaaaaaaaaa: \" << aaaaaaaaaaaaaaaa;");
-  verifyFormat(
-      "llvm::outs() << \"aaaaaaaaaaaaaaaaa = \" << aaaaaaaaaaaaaaaaa\n"
-      "             << \"bbbbbbbbbbbbbbbbb = \" << bbbbbbbbbbbbbbbbb\n"
-      "             << \"ccccccccccccccccc = \" << ccccccccccccccccc\n"
-      "             << \"ddddddddddddddddd = \" << ddddddddddddddddd\n"
-      "             << \"eeeeeeeeeeeeeeeee = \" << eeeeeeeeeeeeeeeee;");
-  verifyFormat("llvm::outs() << aaaaaaaaaaaaaaaaaaaaaaaa << \"=\"\n"
-               "             << bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb;");
-  verifyFormat(
-      "void f() {\n"
-      "  llvm::outs() << \"aaaaaaaaaaaaaaaaaaaa: \"\n"
-      "               << aaaaaaaaaaaaa(aaaaaaaaaaaaaaaaaaaaaaaaaaaa);\n"
-      "}");
   verifyFormat("llvm::outs() << \"aaaaaaaaaaaaaaaa: \"\n"
                "             << aaaaaaaa.aaaaaaaaaaaa(aaa)->aaaaaaaaaaaaaa();");
   verifyFormat("llvm::errs() << aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(\n"
@@ -5142,22 +5119,6 @@ TEST_F(FormatTest, AlignsPipes) {
                "       bbb)\n"
                "    << a << b;");
 
-  // Breaking before the first "<<" is generally not desirable.
-  verifyFormat(
-      "llvm::errs()\n"
-      "    << \"aaaaaaaaaaaaaaaaaaa: \" << aaaaaaaaaaaaaaaaaaaaaaaaaaaa\n"
-      "    << \"aaaaaaaaaaaaaaaaaaa: \" << aaaaaaaaaaaaaaaaaaaaaaaaaaaa\n"
-      "    << \"aaaaaaaaaaaaaaaaaaa: \" << aaaaaaaaaaaaaaaaaaaaaaaaaaaa\n"
-      "    << \"aaaaaaaaaaaaaaaaaaa: \" << aaaaaaaaaaaaaaaaaaaaaaaaaaaa;",
-      getLLVMStyleWithColumns(70));
-  verifyFormat("llvm::errs() << \"aaaaaaaaaaaaaaaaaaa: \"\n"
-               "             << aaaaaaaaaaaaaaaaaaaaaaaaaaaa\n"
-               "             << \"aaaaaaaaaaaaaaaaaaa: \"\n"
-               "             << aaaaaaaaaaaaaaaaaaaaaaaaaaaa\n"
-               "             << \"aaaaaaaaaaaaaaaaaaa: \"\n"
-               "             << aaaaaaaaaaaaaaaaaaaaaaaaaaaa;",
-               getLLVMStyleWithColumns(70));
-
   // But sometimes, breaking before the first "<<" is desirable.
   verifyFormat("Diag(aaaaaaaaaaaaaaaaaaaa, aaaaaaaa)\n"
                "    << aaaaaaaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaa);");
@@ -5203,6 +5164,55 @@ TEST_F(FormatTest, AlignsPipes) {
   verifyFormat("llvm::errs() << \"\\n\" << bbbbbbbbbbbbbbbbbbbbbb << \"\\n\";");
 }
 
+TEST_F(FormatTest, KeepStringLabelValuePairsOnALine) {
+  verifyFormat("return out << \"somepacket = {\\n\"\n"
+               "           << \" aaaaaa = \" << pkt.aaaaaa << \"\\n\"\n"
+               "           << \" bbbb = \" << pkt.bbbb << \"\\n\"\n"
+               "           << \" cccccc = \" << pkt.cccccc << \"\\n\"\n"
+               "           << \" ddd = [\" << pkt.ddd << \"]\\n\"\n"
+               "           << \"}\";");
+
+  verifyFormat("llvm::outs() << \"aaaaaaaaaaaaaaaa: \" << aaaaaaaaaaaaaaaa\n"
+               "             << \"aaaaaaaaaaaaaaaa: \" << aaaaaaaaaaaaaaaa\n"
+               "             << \"aaaaaaaaaaaaaaaa: \" << aaaaaaaaaaaaaaaa;");
+  verifyFormat(
+      "llvm::outs() << \"aaaaaaaaaaaaaaaaa = \" << aaaaaaaaaaaaaaaaa\n"
+      "             << \"bbbbbbbbbbbbbbbbb = \" << bbbbbbbbbbbbbbbbb\n"
+      "             << \"ccccccccccccccccc = \" << ccccccccccccccccc\n"
+      "             << \"ddddddddddddddddd = \" << ddddddddddddddddd\n"
+      "             << \"eeeeeeeeeeeeeeeee = \" << eeeeeeeeeeeeeeeee;");
+  verifyFormat("llvm::outs() << aaaaaaaaaaaaaaaaaaaaaaaa << \"=\"\n"
+               "             << bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb;");
+  verifyFormat(
+      "void f() {\n"
+      "  llvm::outs() << \"aaaaaaaaaaaaaaaaaaaa: \"\n"
+      "               << aaaaaaaaaaaaa(aaaaaaaaaaaaaaaaaaaaaaaaaaaa);\n"
+      "}");
+
+  // Breaking before the first "<<" is generally not desirable.
+  verifyFormat(
+      "llvm::errs()\n"
+      "    << \"aaaaaaaaaaaaaaaaaaa: \" << aaaaaaaaaaaaaaaaaaaaaaaaaaaa\n"
+      "    << \"aaaaaaaaaaaaaaaaaaa: \" << aaaaaaaaaaaaaaaaaaaaaaaaaaaa\n"
+      "    << \"aaaaaaaaaaaaaaaaaaa: \" << aaaaaaaaaaaaaaaaaaaaaaaaaaaa\n"
+      "    << \"aaaaaaaaaaaaaaaaaaa: \" << aaaaaaaaaaaaaaaaaaaaaaaaaaaa;",
+      getLLVMStyleWithColumns(70));
+  verifyFormat("llvm::errs() << \"aaaaaaaaaaaaaaaaaaa: \"\n"
+               "             << aaaaaaaaaaaaaaaaaaaaaaaaaaaa\n"
+               "             << \"aaaaaaaaaaaaaaaaaaa: \"\n"
+               "             << aaaaaaaaaaaaaaaaaaaaaaaaaaaa\n"
+               "             << \"aaaaaaaaaaaaaaaaaaa: \"\n"
+               "             << aaaaaaaaaaaaaaaaaaaaaaaaaaaa;",
+               getLLVMStyleWithColumns(70));
+
+  verifyFormat("string v = \"aaaaaaaaaaaaaaaa: \" + aaaaaaaaaaaaaaaa +\n"
+               "           \"aaaaaaaaaaaaaaaa: \" + aaaaaaaaaaaaaaaa +\n"
+               "           \"aaaaaaaaaaaaaaaa: \" + aaaaaaaaaaaaaaaa;");
+  verifyFormat("string v = StrCat(\"aaaaaaaaaaaaaaaa: \", aaaaaaaaaaaaaaaa,\n"
+               "                  \"aaaaaaaaaaaaaaaa: \", aaaaaaaaaaaaaaaa,\n"
+               "                  \"aaaaaaaaaaaaaaaa: \", aaaaaaaaaaaaaaaa);");
+}
+
 TEST_F(FormatTest, UnderstandsEquals) {
   verifyFormat(
       "aaaaaaaaaaaaaaaaa =\n"