diff --git a/lib/Target/X86/X86InstrInfo.td b/lib/Target/X86/X86InstrInfo.td
index 79ce509412f..35631d50f41 100644
--- a/lib/Target/X86/X86InstrInfo.td
+++ b/lib/Target/X86/X86InstrInfo.td
@@ -1523,10 +1523,11 @@ def : MnemonicAlias<"call", "calll">, Requires<[In32BitMode]>;
 def : MnemonicAlias<"call", "callq">, Requires<[In64BitMode]>;
 
 def : MnemonicAlias<"cbw",  "cbtw">;
+def : MnemonicAlias<"cwde", "cwtl">;
 def : MnemonicAlias<"cwd",  "cwtd">;
 def : MnemonicAlias<"cdq", "cltd">;
-def : MnemonicAlias<"cwde", "cwtl">;
 def : MnemonicAlias<"cdqe", "cltq">;
+def : MnemonicAlias<"cqo", "cqto">;
 
 // lret maps to lretl, it is not ambiguous with lretq.
 def : MnemonicAlias<"lret", "lretl">;
diff --git a/test/MC/X86/x86-64.s b/test/MC/X86/x86-64.s
index 6c836fca907..4ec579a7a1f 100644
--- a/test/MC/X86/x86-64.s
+++ b/test/MC/X86/x86-64.s
@@ -459,6 +459,7 @@ cwtl  // CHECK: cwtl
 cbw   // CHECK: cbtw
 cwd   // CHECK: cwtd
 cdq   // CHECK: cltd
+cqo   // CHECK: cqto
 
 // rdar://8456378 and PR7557 - fstsw
 fstsw %ax