avoid LDS data hazard in gemm_softmax_gemm pipeline

include/ck/tensor_operation/gpu/grid/gridwise_batched_gemm_softmax_gemm_xdl_cshuffle_v1.hpp

@@ -717,7 +717,6 @@ struct GridwiseBatchedGemmSoftmaxGemm_Xdl_CShuffle
             running_sum_new = mathext::exp(running_max - running_max_new) * running_sum +
                               mathext::exp(max - running_max_new) * sum;
 
-            block_sync_lds();
             // gemm1
             {
                 // TODO: explore using dynamic buffer for a1 thread buffer
@@ -736,12 +735,13 @@ struct GridwiseBatchedGemmSoftmaxGemm_Xdl_CShuffle
                 b1_blockwise_copy.MoveSrcSliceWindow(b1_grid_desc_bk0_n_bk1,
                                                      b1_block_slice_copy_step);
 
+                block_sync_lds(); // wait for gemm0 LDS read
+
                 b1_blockwise_copy.RunWrite(b1_block_desc_bk0_n_bk1, b1_block_buf);
 
                 // main body
                 if constexpr(num_gemm1_k_block_inner_loop > 1)
                 {
-
                     static_for<0, num_gemm1_k_block_inner_loop - 1, 1>{}([&](auto i) {
                         a1_blockwise_copy.Run(acc_thread_desc_k0_m_k1,
                                               make_tuple(Number<i * A1ThreadSliceK0>{}, I0, I0),
@@ -749,6 +749,7 @@ struct GridwiseBatchedGemmSoftmaxGemm_Xdl_CShuffle
                                               a1_thread_desc_k0_m_k1,
                                               make_tuple(I0, I0, I0),
                                               a1_thread_buf);
+
                         b1_blockwise_copy.RunRead(b1_grid_desc_bk0_n_bk1, b1_grid_buf);
 
                         block_sync_lds();
@@ -817,6 +818,7 @@ struct GridwiseBatchedGemmSoftmaxGemm_Xdl_CShuffle
             running_max = running_max_new;
             running_sum = running_sum_new;
 
+            block_sync_lds(); // wait for gemm1 LDS read
         } while(++gemm1_k_block_outer_index < num_gemm1_k_block_outer_loop); // end j loop
 
         // shuffle C and write out