diff --git a/mlir/include/mlir/IR/OpImplementation.h b/mlir/include/mlir/IR/OpImplementation.h
--- a/mlir/include/mlir/IR/OpImplementation.h
+++ b/mlir/include/mlir/IR/OpImplementation.h
@@ -326,9 +326,27 @@
   /// Parse a '<' token.
   virtual ParseResult parseLess() = 0;
 
+  /// Parse a '<' token if present.
+  virtual ParseResult parseOptionalLess() = 0;
+
   /// Parse a '>' token.
   virtual ParseResult parseGreater() = 0;
 
+  /// Parse a '>' token if present.
+  virtual ParseResult parseOptionalGreater() = 0;
+
+  /// Parse a '+' token.
+  virtual ParseResult parsePlus() = 0;
+
+  /// Parse a '+' token if present.
+  virtual ParseResult parseOptionalPlus() = 0;
+
+  /// Parse a '*' token.
+  virtual ParseResult parseStar() = 0;
+
+  /// Parse a '*' token if present.
+  virtual ParseResult parseOptionalStar() = 0;
+
   /// Parse a given keyword.
   ParseResult parseKeyword(StringRef keyword, const Twine &msg = "") {
     auto loc = getCurrentLocation();
diff --git a/mlir/lib/Parser/Parser.cpp b/mlir/lib/Parser/Parser.cpp
--- a/mlir/lib/Parser/Parser.cpp
+++ b/mlir/lib/Parser/Parser.cpp
@@ -994,11 +994,21 @@
     return parser.parseToken(Token::less, "expected '<'");
   }
 
+  /// Parse a '<' token if present.
+  ParseResult parseOptionalLess() override {
+    return success(parser.consumeIf(Token::less));
+  }
+
   /// Parse a '>' token.
   ParseResult parseGreater() override {
     return parser.parseToken(Token::greater, "expected '>'");
   }
 
+  /// Parse a '>' token if present.
+  ParseResult parseOptionalGreater() override {
+    return success(parser.consumeIf(Token::greater));
+  }
+
   /// Parse a `(` token.
   ParseResult parseLParen() override {
     return parser.parseToken(Token::l_paren, "expected '('");
@@ -1044,6 +1054,26 @@
     return success(parser.consumeIf(Token::r_square));
   }
 
+  /// Parses a '+' token.
+  ParseResult parsePlus() override {
+    return parser.parseToken(Token::plus, "expected '+'");
+  }
+
+  /// Parses a '+' token if present.
+  ParseResult parseOptionalPlus() override {
+    return success(parser.consumeIf(Token::plus));
+  }
+
+  /// Parses a '*' token.
+  ParseResult parseStar() override {
+    return parser.parseToken(Token::star, "expected '*'");
+  }
+
+  /// Parses a '*' token if present.
+  ParseResult parseOptionalStar() override {
+    return success(parser.consumeIf(Token::star));
+  }
+
   //===--------------------------------------------------------------------===//
   // Attribute Parsing
   //===--------------------------------------------------------------------===//
diff --git a/mlir/test/lib/Dialect/Test/TestOps.td b/mlir/test/lib/Dialect/Test/TestOps.td
--- a/mlir/test/lib/Dialect/Test/TestOps.td
+++ b/mlir/test/lib/Dialect/Test/TestOps.td
@@ -1380,7 +1380,7 @@
 
 def FormatLiteralOp : TEST_Op<"format_literal_op"> {
   let assemblyFormat = [{
-    `keyword_$.` `->` `:` `,` `=` `<` `>` `(` `)` `[` `]` `` `(` ` ` `)` attr-dict
+    `keyword_$.` `->` `:` `,` `=` `<` `>` `(` `)` `[` `]` `` `(` ` ` `)` `+` `*` attr-dict
   }];
 }
 
diff --git a/mlir/test/mlir-tblgen/op-format-spec.td b/mlir/test/mlir-tblgen/op-format-spec.td
--- a/mlir/test/mlir-tblgen/op-format-spec.td
+++ b/mlir/test/mlir-tblgen/op-format-spec.td
@@ -309,7 +309,7 @@
 }]>;
 // CHECK-NOT: error
 def LiteralValid : TestFormat_Op<"literal_valid", [{
-  `_` `:` `,` `=` `<` `>` `(` `)` `[` `]` ` ` `` `->` `abc$._`
+  `_` `:` `,` `=` `<` `>` `(` `)` `[` `]` `+` `*` ` ` `` `->` `abc$._`
   attr-dict
 }]>;
 
diff --git a/mlir/test/mlir-tblgen/op-format.mlir b/mlir/test/mlir-tblgen/op-format.mlir
--- a/mlir/test/mlir-tblgen/op-format.mlir
+++ b/mlir/test/mlir-tblgen/op-format.mlir
@@ -5,8 +5,8 @@
 // CHECK: %[[MEMREF:.*]] =
 %memref = "foo.op"() : () -> (memref<1xf64>)
 
-// CHECK: test.format_literal_op keyword_$. -> :, = <> () []( ) {foo.some_attr}
-test.format_literal_op keyword_$. -> :, = <> () []( ) {foo.some_attr}
+// CHECK: test.format_literal_op keyword_$. -> :, = <> () []( ) + * {foo.some_attr}
+test.format_literal_op keyword_$. -> :, = <> () []( ) + * {foo.some_attr}
 
 // CHECK: test.format_attr_op 10
 // CHECK-NOT: {attr
diff --git a/mlir/tools/mlir-tblgen/OpFormatGen.cpp b/mlir/tools/mlir-tblgen/OpFormatGen.cpp
--- a/mlir/tools/mlir-tblgen/OpFormatGen.cpp
+++ b/mlir/tools/mlir-tblgen/OpFormatGen.cpp
@@ -281,7 +281,7 @@
   // If there is only one character, this must either be punctuation or a
   // single character bare identifier.
   if (value.size() == 1)
-    return isalpha(front) || StringRef("_:,=<>()[]{}?").contains(front);
+    return isalpha(front) || StringRef("_:,=<>()[]{}?+*").contains(front);
 
   // Check the punctuation that are larger than a single character.
   if (value == "->")
@@ -762,7 +762,9 @@
               .Case(")", "RParen()")
               .Case("[", "LSquare()")
               .Case("]", "RSquare()")
-              .Case("?", "Question()");
+              .Case("?", "Question()")
+              .Case("+", "Plus()")
+              .Case("*", "Star()");
 }
 
 /// Generate the storage code required for parsing the given element.