diff --git a/src/emit_insn/insn_args_calculator.cc b/src/emit_insn/insn_args_calculator.cc
index 2e6a7144cd5a8c20b59b7b37826bbd6827e42581..a05af0ccc2af99fe6457d702a109e1beebac9b77 100644
--- a/src/emit_insn/insn_args_calculator.cc
+++ b/src/emit_insn/insn_args_calculator.cc
@@ -848,6 +848,9 @@ BisectionInfoWrapper SeparateComInfoToBisectionInfoList(const StmtInfoList &dst_
       new_strides.Set(i, new_strides[i + 1] * new_dims[i + 1]);
     }
     new_dims.Set(new_dims.size() - 1, simd_len);
+  } else if (simd_var->name_hint == un_def_var) {
+    new_dims.Set(var_idx, extent);
+    new_strides.Set(var_idx, last_dim_len);
   } else {
     new_dims = {extent};
   }
@@ -946,7 +949,7 @@ BisectionInfoWrapper SeparateComInfoToBisectionInfoList(const StmtInfoList &dst_
         src_tmp_info1.GetNode()->shape_ = dst_tmp_info->shape_;
         src_tmp_info1.GetNode()->strides_ = dst_tmp_info->strides_;
         src_tmp_info1.GetNode()->var_ = dst_tmp_info->var_;
-        src_tmp_info1.GetNode()->index_ = dst_tmp_info->index_;
+        src_tmp_info1.GetNode()->index_ = 0;
       }
     }
 
diff --git a/src/pass/emit_insn.cc b/src/pass/emit_insn.cc
index 38b90a85e12739fd2f459deca7c43225b63119b5..c8d7df0559d5c15c5d9d5f09f825ee6a68743d6e 100644
--- a/src/pass/emit_insn.cc
+++ b/src/pass/emit_insn.cc
@@ -453,6 +453,25 @@ class RegCondition : public IRMutator {
   int reg_cnt_{0};
 };
 
+class ForSimplify : public IRMutator {
+ public:
+  ForSimplify() = default;
+  ~ForSimplify() override = default;
+
+ private:
+  Stmt Mutate_(const For *op, const Stmt &s) final {
+    if ((op->extent.as<IntImm>() && op->extent.as<IntImm>()->value == 1) ||
+        (op->extent.as<UIntImm>() && op->extent.as<UIntImm>()->value == 1)) {
+      Map<Var, Expr> var_map;
+      var_map.Set(op->loop_var, op->min);
+      auto body = Mutate(op->body);
+      body = Simplify(Substitute(body, var_map));
+      return body;
+    }
+    return IRMutator::Mutate_(op, s);
+  }
+};
+
 Stmt EmitInsn(Stmt stmt, bool enable_bisect, bool enable_cover_protect, const Map<Tensor, Buffer> &extern_buffer,
               bool is_dynamic) {
   char *debug_var = getenv("DEBUG_MODE");
@@ -463,6 +482,7 @@ Stmt EmitInsn(Stmt stmt, bool enable_bisect, bool enable_cover_protect, const Ma
   if (debug_mode) {
     stmt = EmitInsnDebug(stmt);
   }
+  stmt = ForSimplify().Mutate(stmt);
   stmt = PreEmit().Mutate(stmt);
   if (!is_dynamic) {
     char *comment_var = getenv("COMMENT_LEVEL");