diff --git a/src/backend_x64/emit_x64.cpp b/src/backend_x64/emit_x64.cpp
index 2293f5a4..ad71baaf 100644
--- a/src/backend_x64/emit_x64.cpp
+++ b/src/backend_x64/emit_x64.cpp
@@ -845,6 +845,16 @@ void EmitX64::EmitSubWithCarry(IR::Block& block, IR::Inst* inst) {
     }
 }
 
+void EmitX64::EmitSub64(IR::Block& block, IR::Inst* inst) {
+    IR::Value a = inst->GetArg(0);
+    IR::Value b = inst->GetArg(1);
+
+    X64Reg result = reg_alloc.UseDefRegister(a, inst, any_gpr);
+    OpArg op_arg = reg_alloc.UseOpArg(b, any_gpr);
+
+    code->SUB(64, R(result), op_arg);
+}
+
 void EmitX64::EmitMul(IR::Block&, IR::Inst* inst) {
     IR::Value a = inst->GetArg(0);
     IR::Value b = inst->GetArg(1);
diff --git a/src/frontend/ir/ir_emitter.cpp b/src/frontend/ir/ir_emitter.cpp
index b5315cca..e9b5b87d 100644
--- a/src/frontend/ir/ir_emitter.cpp
+++ b/src/frontend/ir/ir_emitter.cpp
@@ -210,6 +210,10 @@ IR::Value IREmitter::Sub(const IR::Value& a, const IR::Value& b) {
     return Inst(IR::Opcode::SubWithCarry, {a, b, Imm1(1)});
 }
 
+IR::Value IREmitter::Sub64(const IR::Value& a, const IR::Value& b) {
+    return Inst(IR::Opcode::Sub64, {a, b});
+}
+
 IR::Value IREmitter::Mul(const IR::Value& a, const IR::Value& b) {
     return Inst(IR::Opcode::Mul, {a, b});
 }
diff --git a/src/frontend/ir/ir_emitter.h b/src/frontend/ir/ir_emitter.h
index 2a7a16e1..c0e312c9 100644
--- a/src/frontend/ir/ir_emitter.h
+++ b/src/frontend/ir/ir_emitter.h
@@ -75,6 +75,7 @@ public:
     IR::Value Add64(const IR::Value& a, const IR::Value& b);
     ResultAndCarryAndOverflow SubWithCarry(const IR::Value& a, const IR::Value& b, const IR::Value& carry_in);
     IR::Value Sub(const IR::Value& a, const IR::Value& b);
+    IR::Value Sub64(const IR::Value& a, const IR::Value& b);
     IR::Value Mul(const IR::Value& a, const IR::Value& b);
     IR::Value Mul64(const IR::Value& a, const IR::Value& b);
     IR::Value And(const IR::Value& a, const IR::Value& b);
diff --git a/src/frontend/ir/opcodes.inc b/src/frontend/ir/opcodes.inc
index 68736934..7c17a45e 100644
--- a/src/frontend/ir/opcodes.inc
+++ b/src/frontend/ir/opcodes.inc
@@ -42,6 +42,7 @@ OPCODE(RotateRightExtended,     T::U32,         T::U32,         T::U1
 OPCODE(AddWithCarry,            T::U32,         T::U32,         T::U32,         T::U1           )
 OPCODE(SubWithCarry,            T::U32,         T::U32,         T::U32,         T::U1           )
 OPCODE(Add64,                   T::U64,         T::U64,         T::U64                          )
+OPCODE(Sub64,                   T::U64,         T::U64,         T::U64                          )
 OPCODE(Mul,                     T::U32,         T::U32,         T::U32                          )
 OPCODE(Mul64,                   T::U64,         T::U64,         T::U64                          )
 OPCODE(And,                     T::U32,         T::U32,         T::U32                          )