diff --git a/llvm/lib/BinaryFormat/MsgPackDocumentYAML.cpp b/llvm/lib/BinaryFormat/MsgPackDocumentYAML.cpp
index 80b421d5f752e..fbf871f709a64 100644
--- a/llvm/lib/BinaryFormat/MsgPackDocumentYAML.cpp
+++ b/llvm/lib/BinaryFormat/MsgPackDocumentYAML.cpp
@@ -29,6 +29,10 @@ struct ScalarDocNode : DocNode {
   StringRef getYAMLTag() const;
 };
 
+bool isJSONSchemaBoolLiteral(StringRef S) {
+  return S == "true" || S == "false";
+}
+
 } // namespace
 
 /// Convert this DocNode to a string, assuming it is scalar.
@@ -84,11 +88,18 @@ StringRef DocNode::fromString(StringRef S, StringRef Tag) {
     *this = getDocument()->getNode();
     return "";
   }
-  if (Tag == "!bool" || Tag == "") {
+  if (Tag == "!bool") {
     *this = getDocument()->getNode(false);
-    StringRef Err = yaml::ScalarTraits<bool>::input(S, nullptr, getBool());
-    if (Err == "" || Tag != "")
-      return Err;
+    return yaml::ScalarTraits<bool>::input(S, nullptr, getBool());
+  }
+  // FIXME: This enforces the "JSON Schema" tag resolution for boolean literals,
+  // defined at https://yaml.org/spec/1.2.2/#json-schema which we adopt because
+  // the more general pre-1.2 resolution includes many common strings (e.g. "n",
+  // "no", "y", "yes", ...). This should be handled at the YAMLTraits level, but
+  // that change would have a much broader impact.
+  if (Tag == "" && isJSONSchemaBoolLiteral(S)) {
+    *this = getDocument()->getNode(S == "true");
+    return "";
   }
   if (Tag == "!float" || Tag == "") {
     *this = getDocument()->getNode(0.0);
diff --git a/llvm/unittests/BinaryFormat/MsgPackDocumentTest.cpp b/llvm/unittests/BinaryFormat/MsgPackDocumentTest.cpp
index 6a6ad7010f629..60b2b28c7fac9 100644
--- a/llvm/unittests/BinaryFormat/MsgPackDocumentTest.cpp
+++ b/llvm/unittests/BinaryFormat/MsgPackDocumentTest.cpp
@@ -420,3 +420,89 @@ TEST(MsgPackDocument, TestInputYAMLMap) {
   ASSERT_EQ(SS.getKind(), Type::String);
   ASSERT_EQ(SS.getString(), "2");
 }
+
+TEST(MsgPackDocument, TestYAMLBoolean) {
+  Document Doc;
+  auto GetFirst = [](Document &Doc) { return Doc.getRoot().getArray()[0]; };
+  auto ToYAML = [](Document &Doc) {
+    std::string S;
+    raw_string_ostream OS(S);
+    Doc.toYAML(OS);
+    return S;
+  };
+
+  bool Ok;
+
+  Ok = Doc.fromYAML("- n\n");
+  ASSERT_TRUE(Ok);
+  ASSERT_EQ(GetFirst(Doc).getKind(), Type::String);
+  ASSERT_EQ(GetFirst(Doc).getString(), "n");
+  ASSERT_EQ(ToYAML(Doc), "---\n- n\n...\n");
+
+  Ok = Doc.fromYAML("- y\n");
+  ASSERT_TRUE(Ok);
+  ASSERT_EQ(GetFirst(Doc).getKind(), Type::String);
+  ASSERT_EQ(GetFirst(Doc).getString(), "y");
+  ASSERT_EQ(ToYAML(Doc), "---\n- y\n...\n");
+
+  Ok = Doc.fromYAML("- no\n");
+  ASSERT_TRUE(Ok);
+  ASSERT_EQ(GetFirst(Doc).getKind(), Type::String);
+  ASSERT_EQ(GetFirst(Doc).getString(), "no");
+  ASSERT_EQ(ToYAML(Doc), "---\n- no\n...\n");
+
+  Ok = Doc.fromYAML("- yes\n");
+  ASSERT_TRUE(Ok);
+  ASSERT_EQ(GetFirst(Doc).getKind(), Type::String);
+  ASSERT_EQ(GetFirst(Doc).getString(), "yes");
+  ASSERT_EQ(ToYAML(Doc), "---\n- yes\n...\n");
+
+  Ok = Doc.fromYAML("- false\n");
+  ASSERT_TRUE(Ok);
+  ASSERT_EQ(GetFirst(Doc).getKind(), Type::Boolean);
+  ASSERT_EQ(GetFirst(Doc).getBool(), false);
+  ASSERT_EQ(ToYAML(Doc), "---\n- false\n...\n");
+
+  Ok = Doc.fromYAML("- true\n");
+  ASSERT_TRUE(Ok);
+  ASSERT_EQ(GetFirst(Doc).getKind(), Type::Boolean);
+  ASSERT_EQ(GetFirst(Doc).getBool(), true);
+  ASSERT_EQ(ToYAML(Doc), "---\n- true\n...\n");
+
+  Ok = Doc.fromYAML("- !str false\n");
+  ASSERT_TRUE(Ok);
+  ASSERT_EQ(GetFirst(Doc).getKind(), Type::String);
+  ASSERT_EQ(GetFirst(Doc).getString(), "false");
+  ASSERT_EQ(ToYAML(Doc), "---\n- !str 'false'\n...\n");
+
+  Ok = Doc.fromYAML("- !str true\n");
+  ASSERT_TRUE(Ok);
+  ASSERT_EQ(GetFirst(Doc).getKind(), Type::String);
+  ASSERT_EQ(GetFirst(Doc).getString(), "true");
+  ASSERT_EQ(ToYAML(Doc), "---\n- !str 'true'\n...\n");
+
+  Ok = Doc.fromYAML("- !bool false\n");
+  ASSERT_TRUE(Ok);
+  ASSERT_EQ(GetFirst(Doc).getKind(), Type::Boolean);
+  ASSERT_EQ(GetFirst(Doc).getBool(), false);
+  ASSERT_EQ(ToYAML(Doc), "---\n- false\n...\n");
+
+  Ok = Doc.fromYAML("- !bool true\n");
+  ASSERT_TRUE(Ok);
+  ASSERT_EQ(GetFirst(Doc).getKind(), Type::Boolean);
+  ASSERT_EQ(GetFirst(Doc).getBool(), true);
+  ASSERT_EQ(ToYAML(Doc), "---\n- true\n...\n");
+
+  // FIXME: A fix for these requires changes in YAMLParser/YAMLTraits.
+  Ok = Doc.fromYAML("- \"false\"\n");
+  ASSERT_TRUE(Ok);
+  ASSERT_EQ(GetFirst(Doc).getKind(), Type::Boolean);
+  ASSERT_EQ(GetFirst(Doc).getBool(), false);
+  ASSERT_EQ(ToYAML(Doc), "---\n- false\n...\n");
+
+  Ok = Doc.fromYAML("- \"true\"\n");
+  ASSERT_TRUE(Ok);
+  ASSERT_EQ(GetFirst(Doc).getKind(), Type::Boolean);
+  ASSERT_EQ(GetFirst(Doc).getBool(), true);
+  ASSERT_EQ(ToYAML(Doc), "---\n- true\n...\n");
+}