diff --git a/taichi/codegen/amdgpu/codegen_amdgpu.cpp b/taichi/codegen/amdgpu/codegen_amdgpu.cpp
index 9d4f4ac10b39fa..5b2431ef54eb54 100644
--- a/taichi/codegen/amdgpu/codegen_amdgpu.cpp
+++ b/taichi/codegen/amdgpu/codegen_amdgpu.cpp
@@ -65,13 +65,7 @@ class TaskCodeGenAMDGPU : public TaskCodeGenLLVM {
       TI_NOT_IMPLEMENTED                                                \
     }                                                                   \
   }
-    if (op == UnaryOpType::logic_not) {
-      if (input_taichi_type->is_primitive(PrimitiveTypeID::i32)) {
-        llvm_val[stmt] = call("logic_not_i32", input);
-      } else {
-        TI_NOT_IMPLEMENTED
-      }
-    } else if (op == UnaryOpType::abs) {
+    if (op == UnaryOpType::abs) {
       if (input_taichi_type->is_primitive(PrimitiveTypeID::f16)) {
         llvm_val[stmt] = call("__ocml_fasb_f16", input);
       } else if (input_taichi_type->is_primitive(PrimitiveTypeID::f32)) {
diff --git a/taichi/codegen/cuda/codegen_cuda.cpp b/taichi/codegen/cuda/codegen_cuda.cpp
index dd5b8216759085..b39586b3b446a5 100644
--- a/taichi/codegen/cuda/codegen_cuda.cpp
+++ b/taichi/codegen/cuda/codegen_cuda.cpp
@@ -257,12 +257,6 @@ class TaskCodeGenCUDA : public TaskCodeGenLLVM {
       } else {
         TI_NOT_IMPLEMENTED
       }
-    } else if (op == UnaryOpType::logic_not) {
-      if (input_taichi_type->is_primitive(PrimitiveTypeID::i32)) {
-        llvm_val[stmt] = call("logic_not_i32", input);
-      } else {
-        TI_NOT_IMPLEMENTED
-      }
     } else if (op == UnaryOpType::frexp) {
       auto stype = tlctx->get_data_type(stmt->ret_type.ptr_removed());
       auto res = builder->CreateAlloca(stype);
diff --git a/taichi/codegen/llvm/codegen_llvm.cpp b/taichi/codegen/llvm/codegen_llvm.cpp
index 30cd0f5aa382f2..829b93399e7e1a 100644
--- a/taichi/codegen/llvm/codegen_llvm.cpp
+++ b/taichi/codegen/llvm/codegen_llvm.cpp
@@ -197,7 +197,6 @@ void TaskCodeGenLLVM::emit_extra_unary(UnaryOpStmt *stmt) {
   UNARY_STD(tan)
   UNARY_STD(tanh)
   UNARY_STD(sgn)
-  UNARY_STD(logic_not)
   UNARY_STD(acos)
   UNARY_STD(asin)
   UNARY_STD(cos)
@@ -524,6 +523,11 @@ void TaskCodeGenLLVM::visit(UnaryOpStmt *stmt) {
     } else {
       llvm_val[stmt] = builder->CreateNeg(input, "neg");
     }
+  } else if (op == UnaryOpType::logic_not) {
+    llvm_val[stmt] = builder->CreateIsNull(input);
+    // TODO: (zhantong) remove this zero ext
+    llvm_val[stmt] = builder->CreateZExt(
+        llvm_val[stmt], tlctx->get_data_type(PrimitiveType::i32));
   }
   UNARY_INTRINSIC(round)
   UNARY_INTRINSIC(floor)
diff --git a/taichi/runtime/llvm/runtime_module/runtime.cpp b/taichi/runtime/llvm/runtime_module/runtime.cpp
index 460beb145e7e77..53547922a2e858 100644
--- a/taichi/runtime/llvm/runtime_module/runtime.cpp
+++ b/taichi/runtime/llvm/runtime_module/runtime.cpp
@@ -229,10 +229,6 @@ i64 max_i64(i64 a, i64 b) {
   return a > b ? a : b;
 }
 
-int32 logic_not_i32(int32 a) {
-  return !a;
-}
-
 float32 sgn_f32(float32 a) {
   float32 b;
   if (a > 0)