save intermediate data to out buffer

paddle/fluid/operators/fusion_gru_op.cc

@@ -266,25 +266,24 @@ class FusionGRUKernel : public framework::OpKernel<T> {
                 batched_input_data, D3);
 
       T* cur_batched_data = batched_input_data;
+      T* cur_out_data = batched_out_data;
       T* cur_prev_hidden_data = prev_hidden_data;
       for (int i = 0; i < cur_bs; ++i) {
         act_gate(D2, cur_batched_data, cur_batched_data);
         // rt = rt*ht_1 inplace result
-        // TODO(TJ): try to save to cur out data
-        // maybe get benifits avoiding cache miss in next gemm
-        blas.VMUL(D, cur_prev_hidden_data, cur_batched_data + D,
-                  cur_batched_data + D);
+        blas.VMUL(D, cur_prev_hidden_data, cur_batched_data + D, cur_out_data);
 
         cur_batched_data += D3;
         cur_prev_hidden_data += D;
+        cur_out_data += D;
       }
 
       cur_batched_data = batched_input_data;
+      cur_out_data = batched_out_data;
       blas.GEMM(CblasNoTrans, CblasNoTrans, cur_bs, D, D, static_cast<T>(1),
-                cur_batched_data + D, D3, wh_state_data, D, static_cast<T>(1),
+                cur_out_data, D, wh_state_data, D, static_cast<T>(1),
                 cur_batched_data + D2, D3);
 
-      T* cur_out_data = batched_out_data;
       cur_prev_hidden_data = prev_hidden_data;
       for (int i = 0; i < cur_bs; ++i) {
         // ht~ = act_state(...)