diff --git a/lib/Parse/ParseStmt.cpp b/lib/Parse/ParseStmt.cpp
index c3595b9..9085b87 100644
--- a/lib/Parse/ParseStmt.cpp
+++ b/lib/Parse/ParseStmt.cpp
@@ -1259,18 +1259,32 @@
   }
 
   // Parse Outputs, if present.
-  if (Tok.is(tok::colon)) {
+  bool AteExtraColon = false;
+  if (Tok.is(tok::colon) || Tok.is(tok::coloncolon)) {
+    // In C++ mode, parse "::" like ": :".
+    AteExtraColon = Tok.is(tok::coloncolon);
     ConsumeToken();
   
-    if (ParseAsmOperandsOpt(Names, Constraints, Exprs))
+    if (!AteExtraColon &&
+        ParseAsmOperandsOpt(Names, Constraints, Exprs))
       return StmtError();
   }
+  
   unsigned NumOutputs = Names.size();
 
   // Parse Inputs, if present.
-  if (Tok.is(tok::colon)) {
-    ConsumeToken();
-    if (ParseAsmOperandsOpt(Names, Constraints, Exprs))
+  if (AteExtraColon ||
+      Tok.is(tok::colon) || Tok.is(tok::coloncolon)) {
+    // In C++ mode, parse "::" like ": :".
+    if (AteExtraColon)
+      AteExtraColon = false;
+    else {
+      AteExtraColon = Tok.is(tok::coloncolon);
+      ConsumeToken();
+    }
+    
+    if (!AteExtraColon &&
+        ParseAsmOperandsOpt(Names, Constraints, Exprs))
       return StmtError();
   }
 
@@ -1281,8 +1295,9 @@
   unsigned NumInputs = Names.size() - NumOutputs;
 
   // Parse the clobbers, if present.
-  if (Tok.is(tok::colon)) {
-    ConsumeToken();
+  if (AteExtraColon || Tok.is(tok::colon)) {
+    if (!AteExtraColon)
+      ConsumeToken();
 
     // Parse the asm-string list for clobbers.
     while (1) {
diff --git a/test/Parser/cxx-stmt.cpp b/test/Parser/cxx-stmt.cpp
index 3fd3e25..fdd573e 100644
--- a/test/Parser/cxx-stmt.cpp
+++ b/test/Parser/cxx-stmt.cpp
@@ -52,3 +52,9 @@
     case Type: i = 7; break;  // no error.
   }
 }
+
+// PR5500
+void f5() {
+  asm volatile ("":: :"memory");
+  asm volatile ("": ::"memory");
+}