write phi elimination

include/opt/phieliminate.h

@@ -0,0 +1,18 @@
+#pragma once
+#include "IR/IR_basic.h"
+#include "cfg.h"
+
+namespace opt {
+class MoveInstruct : public ActionItem {
+ public:
+  std::string src_full;
+  std::string dest_full;
+  MoveInstruct() = default;
+  void RecursivePrint(std::ostream &os) const {
+    throw std::runtime_error("Move instruction is not an actual LLVM IR instruction");
+  }
+};
+}  // namespace opt
+
+
+std::shared_ptr<ModuleItem> PhiEliminate(std::shared_ptr<ModuleItem> src);