Index: lib/Target/X86/X86InstrInfo.td
===================================================================
--- lib/Target/X86/X86InstrInfo.td
+++ lib/Target/X86/X86InstrInfo.td
@@ -1077,9 +1077,16 @@
 
 
 // Constructing a stack frame.
-def ENTER : Ii16<0xC8, RawFrmImm8, (outs), (ins i16imm:$len, i8imm:$lvl),
-                 "enter\t$len, $lvl", [], IIC_ENTER>, Sched<[WriteMicrocoded]>;
+let Defs = [EBP, ESP], Uses = [EBP, ESP], mayLoad = 1, hasSideEffects=0 in
+def ENTER    : Ii16<0xC8, RawFrmImm8, (outs), (ins i16imm:$len, i8imm:$lvl),
+                    "enter\t$len, $lvl", [], IIC_ENTER>, Sched<[WriteMicrocoded]>,
+                    Requires<[Not64BitMode]>;
 
+let Defs = [RBP, RSP], Uses = [RBP, RSP], mayLoad = 1, hasSideEffects=0 in
+def ENTER64  : Ii16<0xC8, RawFrmImm8, (outs), (ins i16imm:$len, i8imm:$lvl),
+                    "enter\t$len, $lvl", [], IIC_ENTER>, Sched<[WriteMicrocoded]>,
+                    Requires<[In64BitMode]>;
+
 let SchedRW = [WriteALU] in {
 let Defs = [EBP, ESP], Uses = [EBP, ESP], mayLoad = 1, hasSideEffects=0 in
 def LEAVE    : I<0xC9, RawFrm,