Add a few Subzero intrinsics (not the atomic ones yet).

src/IceTargetLoweringX8632.h

Index: src/IceTargetLoweringX8632.h
diff --git a/src/IceTargetLoweringX8632.h b/src/IceTargetLoweringX8632.h
index 3ca9ca3cdd839b50b7c6cec5cd2fc7061924736d..a498e1c82a794f4c89a0585508092f9fbe0abe1d 100644
--- a/src/IceTargetLoweringX8632.h
+++ b/src/IceTargetLoweringX8632.h
@@ -70,6 +70,14 @@ public:
         Reg_NUM
   };
 
+  enum SegmentRegisters {
+#define X(val, name)                                                           \
+    val,
+      SEG_REGX8632_TABLE
+#undef X
+    SegReg_NUM
+  };
+
 protected:
   TargetX8632(Cfg *Func);
 
@@ -83,6 +91,7 @@ protected:
   virtual void lowerCast(const InstCast *Inst);
   virtual void lowerFcmp(const InstFcmp *Inst);
   virtual void lowerIcmp(const InstIcmp *Inst);
+  virtual void lowerIntrinsicCall(const InstIntrinsicCall *Inst);
   virtual void lowerLoad(const InstLoad *Inst);
   virtual void lowerPhi(const InstPhi *Inst);
   virtual void lowerRet(const InstRet *Inst);
@@ -246,6 +255,9 @@ protected:
   void _ucomiss(Operand *Src0, Operand *Src1) {
     Context.insert(InstX8632Ucomiss::create(Func, Src0, Src1));
   }
+  void _ud2() {
+    Context.insert(InstX8632UD2::create(Func));
+  }
   void _xor(Variable *Dest, Operand *Src0) {
     Context.insert(InstX8632Xor::create(Func, Dest, Src0));
   }