support 2-dimension target of CTCLossV2

mindspore/ccsrc/backend/kernel_compiler/gpu/nn/ctcloss_gpu_kernel.h

@@ -51,10 +51,12 @@ class CtcLossGpuKernel : public GpuKernel {
     float *grads = GetDeviceAddress<float>(outputs, 1);
 
     // Copy labels/input_lengths/label_length to host as cudnn7.x.x requires
-    void *labels_host = nullptr;
+    int *labels_host = nullptr;
+    int *no_blank_labels_host = nullptr;
     void *input_lengths_host = nullptr;
     void *label_lengths_host = nullptr;
     CHECK_CUDA_RET_WITH_EXCEPT(cudaMallocHost(&labels_host, inputs[1]->size), "cudaMallocHost failed.");
+    CHECK_CUDA_RET_WITH_EXCEPT(cudaMallocHost(&no_blank_labels_host, inputs[1]->size), "cudaMallocHost failed.");
     CHECK_CUDA_RET_WITH_EXCEPT(cudaMallocHost(&input_lengths_host, inputs[2]->size), "cudaMallocHost failed.");
     CHECK_CUDA_RET_WITH_EXCEPT(cudaMallocHost(&label_lengths_host, inputs[3]->size), "cudaMallocHost failed.");
     cudaStream_t stream = reinterpret_cast<cudaStream_t>(stream_ptr);
@@ -68,12 +70,21 @@ class CtcLossGpuKernel : public GpuKernel {
       "cudaMemcpyAsync failed.");
 
     CHECK_CUDA_RET_WITH_EXCEPT(cudaStreamSynchronize(stream), "cudaStreamSynchronize failed.");
+
+    size_t j = 0;
+    for (size_t i = 0; i < inputs[1]->size / sizeof(int); i++) {
+      if (labels_host[i] != 0) {
+        no_blank_labels_host[j] = labels_host[i];
+        j++;
+      }
+    }
+
     size_t workspace_size = 0;
     CHECK_CUDNN_RET_WITH_EXCEPT(
-      cudnnGetCTCLossWorkspaceSize(cudnn_handle_, probs_desc_, probs_desc_, reinterpret_cast<int *>(labels_host),
-                                   reinterpret_cast<int *>(label_lengths_host),
-                                   reinterpret_cast<int *>(input_lengths_host), CUDNN_CTC_LOSS_ALGO_DETERMINISTIC,
-                                   ctcloss_desc_, &workspace_size),
+      cudnnGetCTCLossWorkspaceSize(
+        cudnn_handle_, probs_desc_, probs_desc_, reinterpret_cast<int *>(no_blank_labels_host),
+        reinterpret_cast<int *>(label_lengths_host), reinterpret_cast<int *>(input_lengths_host),
+        CUDNN_CTC_LOSS_ALGO_DETERMINISTIC, ctcloss_desc_, &workspace_size),
       "cudnnGetCTCLossWorkspaceSize failed.");
     void *workspace = device::gpu::GPUMemoryAllocator::GetInstance().AllocTensorMem(workspace_size);
     if (workspace == nullptr) {
@@ -81,7 +92,7 @@ class CtcLossGpuKernel : public GpuKernel {
     }
 
     CHECK_CUDNN_RET_WITH_EXCEPT(
-      cudnnCTCLoss(cudnn_handle_, probs_desc_, probs, reinterpret_cast<int *>(labels_host),
+      cudnnCTCLoss(cudnn_handle_, probs_desc_, probs, reinterpret_cast<int *>(no_blank_labels_host),
                    reinterpret_cast<int *>(label_lengths_host), reinterpret_cast<int *>(input_lengths_host), costs,
                    probs_desc_, grads, CUDNN_CTC_LOSS_ALGO_DETERMINISTIC, ctcloss_desc_, workspace, workspace_size),
       "cudnnCtcLoss failed.");
@@ -91,6 +102,7 @@ class CtcLossGpuKernel : public GpuKernel {
     CHECK_CUDA_RET_WITH_EXCEPT(cudaFreeHost(label_lengths_host), "cudaFreeHost failed.");
     CHECK_CUDA_RET_WITH_EXCEPT(cudaFreeHost(input_lengths_host), "cudaFreeHost failed.");
     CHECK_CUDA_RET_WITH_EXCEPT(cudaFreeHost(labels_host), "cudaFreeHost failed.");
+    CHECK_CUDA_RET_WITH_EXCEPT(cudaFreeHost(no_blank_labels_host), "cudaFreeHost failed.");
     return true;
   }
   bool Init(const CNodePtr &kernel_node) override {