diff --git a/lib/Target/X86/X86RegisterInfo.td b/lib/Target/X86/X86RegisterInfo.td
index d98eea3e377..5263a4934cb 100644
--- a/lib/Target/X86/X86RegisterInfo.td
+++ b/lib/Target/X86/X86RegisterInfo.td
@@ -206,13 +206,6 @@ let Namespace = "X86" in {
   def YMM15: RegisterWithSubRegs<"ymm15", [XMM15]>, DwarfRegAlias<XMM15>;
   }
 
-  // Pseudo-register that aliases the high part of ymm6-ymm15 that is clobbered
-  // by win64 calls.  Doesn't alias the callee-saved xmm6-xmm15.
-  def YMM_HI_6_15 : Register<"ymmhi-6-15"> {
-    let Aliases = [YMM6, YMM7, YMM8, YMM9, YMM10, YMM11, YMM12, YMM13, YMM14,
-                   YMM15];
-  }
-
   class STRegister<string Name, list<Register> A> : Register<Name> {
     let Aliases = A;
   }