diff --git a/src/compiler_llvm/compilation_unit.cc b/src/compiler_llvm/compilation_unit.cc
index 09e193d..32f1786 100644
--- a/src/compiler_llvm/compilation_unit.cc
+++ b/src/compiler_llvm/compilation_unit.cc
@@ -204,7 +204,7 @@
   llvm::TargetMachine* target_machine =
     target->createTargetMachine(target_triple, "", target_attr, target_options,
                                 llvm::Reloc::Static, llvm::CodeModel::Small,
-                                llvm::CodeGenOpt::Aggressive);
+                                llvm::CodeGenOpt::None);
 
   CHECK(target_machine != NULL) << "Failed to create target machine";
 
@@ -220,14 +220,6 @@
   llvm::FunctionPassManager fpm(module_);
   fpm.add(new llvm::TargetData(*target_data));
 
-  // Add optimization pass
-  llvm::PassManagerBuilder pm_builder;
-  pm_builder.Inliner = NULL; // TODO: add some inline in the future
-  pm_builder.OptLevel = 3;
-  pm_builder.DisableSimplifyLibCalls = 1;
-  pm_builder.populateModulePassManager(pm);
-  pm_builder.populateFunctionPassManager(fpm);
-
   // Add passes to emit ELF image
   {
     llvm::formatted_raw_ostream formatted_os(
@@ -245,14 +237,6 @@
     // Add pass to update the frame_size_in_bytes_
     pm.add(new ::UpdateFrameSizePass(this));
 
-    // Run the per-function optimization
-    fpm.doInitialization();
-    for (llvm::Module::iterator F = module_->begin(), E = module_->end();
-         F != E; ++F) {
-      fpm.run(*F);
-    }
-    fpm.doFinalization();
-
     // Run the code generation passes
     pm.run(*module_);
   }