1. Declare e inside the host_gemm_layernorm()

2. Prevent implicit cast in reference code

example/21_gemm_layernorm/gemm_bias_relu_add_layernorm_xdl_welford_fp16.cpp

@@ -87,8 +87,7 @@ auto f_host_tensor_descriptor2d =
         }
     };
 
-void host_gemm_layernorm(Tensor<EMeanVarDataType>& e_m_n,
-                         Tensor<HDataType>& h_m_n,
+void host_gemm_layernorm(Tensor<HDataType>& h_m_n,
                          const Tensor<ADataType>& a_m_k,
                          const Tensor<BDataType>& b_k_n,
                          const Tensor<D0DataType>& bias_n,
@@ -119,6 +118,7 @@ void host_gemm_layernorm(Tensor<EMeanVarDataType>& e_m_n,
                                                                               2,
                                                                               1>;
 
+    Tensor<EMeanVarDataType> e_m_n(HostTensorDescriptor{M, N});
     Tensor<AccDataType> c_m_n(HostTensorDescriptor{M, N});
 
     auto ref_gemm         = ReferenceGemm{};
@@ -129,9 +129,17 @@ void host_gemm_layernorm(Tensor<EMeanVarDataType>& e_m_n,
 
     ref_gemm_invoker.Run(ref_gemm_argument);
 
-    for(int m = 0; m < M; ++m)
-        for(int n = 0; n < N; ++n)
-            cde_element_op(e_m_n(m, n), c_m_n(m, n), bias_n(n), d1_m_n(m, n));
+    for(int n = 0; n < N; ++n)
+    {
+        AccDataType bias = static_cast<AccDataType>(bias_n(n));
+        for(int m = 0; m < M; ++m)
+        {
+            AccDataType e  = static_cast<AccDataType>(e_m_n(m, n));
+            AccDataType d1 = static_cast<AccDataType>(d1_m_n(m, n));
+            cde_element_op(e, c_m_n(m, n), bias, d1);
+            e_m_n(m, n) = static_cast<EMeanVarDataType>(e);
+        }
+    }
 
     ReferenceLayernorm ref_layernorm;
     auto ref_layernorm_invoker = ref_layernorm.MakeInvoker();
@@ -230,11 +238,8 @@ int main()
 
     if(do_verification)
     {
-        Tensor<EMeanVarDataType> e_m_n_host(HostTensorDescriptor{M, N});
         Tensor<HDataType> h_m_n_host(HostTensorDescriptor{M, N});
-
-        host_gemm_layernorm(e_m_n_host,
-                            h_m_n_host,
+        host_gemm_layernorm(h_m_n_host,
                             a_m_k,
                             b_k_n,
                             d0_n,