diff --git a/src/codegen/liverange.cpp b/src/codegen/liverange.cpp
index fc9ef91ab203de8cfbcc50d22ff8a2d1eb20cefe..015af88abc7a297c21baef27b1209372f5a536f3 100644
--- a/src/codegen/liverange.cpp
+++ b/src/codegen/liverange.cpp
@@ -27,11 +27,8 @@ LiveRangeAnalyzer::joinFor(BasicBlock *bb) {
     for (auto succ : bb->get_succ_basic_blocks()) {
         auto &irs = succ->get_instructions();
         auto it = irs.begin();
-        cout << succ->get_name() << endl;
         while (it != irs.end() and it->is_phi())
             ++it;
-        /* if (it == irs.end())
-         *         cout << succ->print() << endl; */
         assert(it != irs.end() && "need to find first_ir from copy-stmt");
         union_ip(out, IN[instr_id.at(&(*it))]);
         // cout << "# " + it->print() << endl;
@@ -85,10 +82,6 @@ LiveRangeAnalyzer::get_dfs_order(Function *func) {
         for (auto succ : bb->get_succ_basic_blocks())
             Q.push_front(succ);
     }
-    cout << func->get_name() << "'s dfs order:\n\t";
-    for (auto bb : BB_DFS_Order)
-        cout << bb->get_name() << " ";
-    cout << endl;
 }
 
 void
diff --git a/src/optimization/CMakeLists.txt b/src/optimization/CMakeLists.txt
index 73ea2d634ed0193e61887bfa56178174d0aa139c..e097d1e9e3c90955a85c1e877188d246d98b890b 100644
--- a/src/optimization/CMakeLists.txt
+++ b/src/optimization/CMakeLists.txt
@@ -1,8 +1,8 @@
 add_library(
         OP_lib STATIC
+        LoopUnroll.cpp
+        ExceptCallMerge.cpp
         Dominators.cpp
         Mem2Reg.cpp
         GVN.cpp
-        LoopUnroll.cpp
-        ExceptCallMerge.cpp
 )
diff --git a/src/optimization/ExceptCallMerge.cpp b/src/optimization/ExceptCallMerge.cpp
index 3427b69e5fe5d210240b6c1138b20117494a2c24..114d7295664a844037720f030f688e47bbbfda7d 100644
--- a/src/optimization/ExceptCallMerge.cpp
+++ b/src/optimization/ExceptCallMerge.cpp
@@ -51,11 +51,10 @@ NegCallMerge::run(Function *func) {
         }
     }
     // remove useless BasicBlocks
-    cout << "remove blocks for function " << func->get_name() << endl;
     for (auto _bb : calls) {
         auto bb = static_cast<BasicBlock *>(_bb);
         if (bb != reserved) {
-            cout << "remove block " << bb->get_name() << endl;
+            cout << "remove block " << bb->get_name() << " in function " << func->get_name() <<  endl;
             auto it = blocks.begin();
             for (; &*it != bb; ++it)
                 ;
diff --git a/src/optimization/LoopUnroll.cpp b/src/optimization/LoopUnroll.cpp
index 6fe3f0b01f37ebb26b1c548b518b37fde845ccff..e4351d881e413b4fc5519c2d41e5944fa7d1dce6 100644
--- a/src/optimization/LoopUnroll.cpp
+++ b/src/optimization/LoopUnroll.cpp
@@ -29,8 +29,8 @@ struct BackEdgeSearcher {
                     type = "back-edge";
                     edges.push_back(edge);
                 }
-                cout << "find " << type << ": " << LoopUnroll::str(edge)
-                     << "\n";
+                /* cout << "find " << type << ": " << LoopUnroll::str(edge)
+                 *      << "\n"; */
             } else
                 dfsrun(succ);
         }