diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index bfd17d203f61..69677aea99ad 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2012-03-07  Jason Merrill  <jason@redhat.com>
+
+	PR c++/52521
+	* mangle.c (write_literal_operator_name): The length comes after the
+	operator prefix.
+
 2012-03-05  Jakub Jelinek  <jakub@redhat.com>
 
 	* pt.c (local_specializations): Change from htab_t into
diff --git a/gcc/cp/mangle.c b/gcc/cp/mangle.c
index 1379e3b881e3..5d6beb5d5782 100644
--- a/gcc/cp/mangle.c
+++ b/gcc/cp/mangle.c
@@ -1292,18 +1292,16 @@ write_source_name (tree identifier)
 }
 
 /* Write a user-defined literal operator.
+          ::= li <source-name>    # "" <source-name>
    IDENTIFIER is an LITERAL_IDENTIFIER_NODE.  */
 
 static void
 write_literal_operator_name (tree identifier)
 {
   const char* suffix = UDLIT_OP_SUFFIX (identifier);
-  char* buffer = XNEWVEC (char, strlen (UDLIT_OP_MANGLED_PREFIX)
-			      + strlen (suffix) + 10);
-  sprintf (buffer, UDLIT_OP_MANGLED_FORMAT, suffix);
-
-  write_unsigned_number (strlen (buffer));
-  write_identifier (buffer);
+  write_identifier (UDLIT_OP_MANGLED_PREFIX);
+  write_unsigned_number (strlen (suffix));
+  write_identifier (suffix);
 }
 
 /* Encode 0 as _, and 1+ as n-1_.  */
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a00408c90a71..83b7c664adc0 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2012-03-07  Jason Merrill  <jason@redhat.com>
+
+	PR c++/52521
+	* g++.dg/cpp0x/udlit-mangle.C: New.
+
 2012-03-06  Pat Haugen <pthaugen@us.ibm.com>
 
 	* gcc.dg/torture/va-arg-25.c: Fix typo for powerpc64-*-* check.
diff --git a/gcc/testsuite/g++.dg/cpp0x/udlit-mangle.C b/gcc/testsuite/g++.dg/cpp0x/udlit-mangle.C
new file mode 100644
index 000000000000..6de31b65ea71
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/udlit-mangle.C
@@ -0,0 +1,8 @@
+// PR c++/52521
+// { dg-options -std=c++0x }
+// { dg-final { scan-assembler "_Zli2_wPKc" } }
+
+int operator "" _w(const char*);
+int main() {
+  123_w;
+}