diff --git a/src/CFGraph/CFGraph.cpp b/src/CFGraph/CFGraph.cpp
index e27590e..a67c4b4 100644
--- a/src/CFGraph/CFGraph.cpp
+++ b/src/CFGraph/CFGraph.cpp
@@ -1254,4 +1254,49 @@ map<FuncInfo*, vector<SAPFOR::BasicBlock*>>
             fileFuncInfoMap[callFrom->fileName].push_back(callFrom);
 
     return buildCFG(commonBlocks, fileFuncInfoMap, settings);
+}
+
+
+void removedUnreachableBlocks(vector<SAPFOR::BasicBlock*>& blocks)
+{
+    set<SAPFOR::BasicBlock*> reachable;
+
+    for (auto& b : blocks)
+        if (b->getInstructions().front()->isHeader() ||
+            b->getInstructions().front()->getInstruction()->getOperation() == SAPFOR::CFG_OP::ENTRY)
+            reachable.insert(b);
+
+    set<SAPFOR::BasicBlock*> worklist = reachable;
+    while (worklist.size() != 0)
+    {
+        set<SAPFOR::BasicBlock*> to_insert;
+
+        for (auto& b : worklist)
+            for (auto& next : b->getNext())
+                if (reachable.insert(next).second)
+                    to_insert.insert(next);
+
+        worklist = to_insert;
+    }
+
+    auto remove_unreachable_it = remove_if(blocks.begin(), blocks.end(),
+        [&reachable](SAPFOR::BasicBlock* b)
+        {
+            if (reachable.find(b) == reachable.end())
+            {
+                for (auto& next : b->getNext())
+                    if (reachable.find(next) != reachable.end())
+                        next->removePrev(b);
+
+                delete b;
+                return true;
+            }
+
+            return false;
+        }
+    );
+
+    reachable.clear();
+
+    blocks.erase(remove_unreachable_it, blocks.end());
 }
\ No newline at end of file
diff --git a/src/CFGraph/CFGraph.h b/src/CFGraph/CFGraph.h
index c828c12..3c7df16 100644
--- a/src/CFGraph/CFGraph.h
+++ b/src/CFGraph/CFGraph.h
@@ -161,3 +161,5 @@ static inline void deleteCFG(std::map<FuncInfo*, std::vector<SAPFOR::BasicBlock*
     }
     cfg.clear();
 }
+
+void removedUnreachableBlocks(std::vector<SAPFOR::BasicBlock*>& blocks);
diff --git a/src/Transformations/DeadCodeRemoving/dead_code.cpp b/src/Transformations/DeadCodeRemoving/dead_code.cpp
index c2b8901..75e218c 100644
--- a/src/Transformations/DeadCodeRemoving/dead_code.cpp
+++ b/src/Transformations/DeadCodeRemoving/dead_code.cpp
@@ -6,6 +6,8 @@
 #include <set>
 #include <algorithm>
 
+#include "../../CFGraph/CFGraph.h"
+
 using std::map;
 using std::string;
 using std::vector;
@@ -88,13 +90,13 @@ static void updateUseDefForInstruction(SAPFOR::BasicBlock* block, SAPFOR::Instru
             instr_operation == SAPFOR::CFG_OP::STORE)
             last_stack_op_useful = true;
 
-        for (auto e : res)
+        for (auto& e : res)
         {
             def.insert(e);
             use.erase(e);
         }
 
-        for (auto e : args)
+        for (auto& e : args)
         {
             use.insert(e);
             def.erase(e);
@@ -164,7 +166,7 @@ public:
         {
             const auto& example = dynamic_cast<DeadCodeAnalysisNode*>(*prev.begin())->next_notempty_out;
             
-            for (auto p : prev)
+            for (auto& p : prev)
             {
                 DeadCodeAnalysisNode* next = dynamic_cast<DeadCodeAnalysisNode*>(p);
 
@@ -188,7 +190,7 @@ public:
         {
             set<DeadCodeAnalysisNode*> current = {};
 
-            for (auto nextP : getPrevBlocks())
+            for (auto& nextP : getPrevBlocks())
             {
                 DeadCodeAnalysisNode* next = dynamic_cast<DeadCodeAnalysisNode*>(nextP);
 
@@ -428,49 +430,7 @@ int removeDeadCode(SgStatement* func,
         printInternalError(convertFileName(__FILE__).c_str(), __LINE__);
 
     auto& cfg_pair = *(cfg.begin());
-
-    // delete unreachable blocks
-
-    set<SAPFOR::BasicBlock*> reachable;
-
-    for (auto b : cfg_pair.second)
-        if(b->getInstructions().front()->isHeader() || 
-           b->getInstructions().front()->getInstruction()->getOperation() == SAPFOR::CFG_OP::ENTRY)
-            reachable.insert(b);
-
-    set<SAPFOR::BasicBlock*> worklist = reachable;
-    while (worklist.size() != 0)
-    {
-        set<SAPFOR::BasicBlock*> to_insert;
-
-        for(auto b : worklist)
-            for(auto next: b->getNext())
-                if(reachable.insert(next).second)
-                    to_insert.insert(next);
-
-        worklist = to_insert;
-    }
-
-    auto remove_unreachable_it = remove_if(cfg_pair.second.begin(), cfg_pair.second.end(), 
-        [&reachable](SAPFOR::BasicBlock* b)
-        {
-            if (reachable.find(b) == reachable.end())
-            {
-                for(auto next: b->getNext())
-                    if(reachable.find(next) != reachable.end())
-                        next->removePrev(b);
-
-                delete b;
-                return true;
-            }
-
-            return false;
-        }
-    );
-
-    reachable.clear();
-
-    cfg_pair.second.erase(remove_unreachable_it, cfg_pair.second.end());
+    removedUnreachableBlocks(cfg_pair.second);
 
 #if DEBUG_IR
     dumpCFG({ cfg_pair }, false);
@@ -481,7 +441,7 @@ int removeDeadCode(SgStatement* func,
     map<string, FuncInfo*> funcByName;
 
     for (auto& byFile : allFuncs)
-        for (auto byFunc : byFile.second)
+        for (auto& byFunc : byFile.second)
             funcByName[byFunc->funcName] = byFunc;
 
     DeadCodeAnalysis analysis_object(func_parameters, funcByName);
diff --git a/src/Utils/version.h b/src/Utils/version.h
index 7465e56..092925c 100644
--- a/src/Utils/version.h
+++ b/src/Utils/version.h
@@ -1,3 +1,3 @@
 #pragma once
 
-#define VERSION_SPF "2429"
+#define VERSION_SPF "2430"