arm_compute v18.11
diff --git a/src/runtime/CL/functions/CLSoftmaxLayer.cpp b/src/runtime/CL/functions/CLSoftmaxLayer.cpp
index 7a20d9f..d671846 100644
--- a/src/runtime/CL/functions/CLSoftmaxLayer.cpp
+++ b/src/runtime/CL/functions/CLSoftmaxLayer.cpp
@@ -29,29 +29,80 @@
 #include "arm_compute/core/Helpers.h"
 #include "arm_compute/core/Types.h"
 #include "arm_compute/core/Utils.h"
+#include "arm_compute/core/utils/misc/ShapeCalculator.h"
 #include "arm_compute/runtime/CL/CLMemoryGroup.h"
 #include "arm_compute/runtime/CL/CLScheduler.h"
 
-using namespace arm_compute;
-
+namespace arm_compute
+{
 CLSoftmaxLayer::CLSoftmaxLayer(std::shared_ptr<IMemoryManager> memory_manager)
-    : _memory_group(std::move(memory_manager)), _max_shift_exp_sum_kernel(), _norm_kernel(), _max(), _sum(), _tmp()
+    : _memory_group(std::move(memory_manager)), _max_shift_exp_sum_kernel(), _norm_kernel(), _flatten_kernel_ptr(), _reshape_kernel(), _max(), _sum(), _tmp(), _input_flattened(), _output_flattened(),
+      _needs_flattening(false)
 {
 }
 
-void CLSoftmaxLayer::configure(const ICLTensor *input, ICLTensor *output, float beta)
+void CLSoftmaxLayer::configure_reshape_input_kernel(const ICLTensor *input, const ICLTensor *output, size_t axis)
+{
+    // Flatten the input
+    const TensorShape shape_flatten = misc::shape_calculator::compute_softmax_shape(input->info(), axis);
+
+    // Initialize the flat input
+    _input_flattened.allocator()->init(input->info()->clone()->set_is_resizable(true).reset_padding().set_tensor_shape(shape_flatten));
+
+    // If we need to flatten the input, we can use CLFlattenKernel or CLReshapeKernel
+    // If flattening on the third axes, we use CLFlattenKernel.
+    // In all other cases we have to use CLReshapeKernel
+    if(axis != 3)
+    {
+        auto reshape_kernel_ptr = support::cpp14::make_unique<CLReshapeLayerKernel>();
+        reshape_kernel_ptr->configure(input, &_input_flattened);
+        _flatten_kernel_ptr = std::move(reshape_kernel_ptr);
+    }
+    else
+    {
+        auto flatten_kernel_ptr = support::cpp14::make_unique<CLFlattenLayerKernel>();
+        flatten_kernel_ptr->configure(input, &_input_flattened);
+        _flatten_kernel_ptr = std::move(flatten_kernel_ptr);
+    }
+
+    // We need to init the output tensor here. Indeed, the reshape kernel expects
+    // both tensors to be already initialized
+    auto_init_if_empty(*output->info(), *input->info()->clone());
+}
+
+void CLSoftmaxLayer::configure(const ICLTensor *input, ICLTensor *output, float beta, size_t axis)
 {
     // Perform validation step
     ARM_COMPUTE_ERROR_ON_NULLPTR(input, output);
-    ARM_COMPUTE_ERROR_THROW_ON(CLSoftmaxLayer::validate(input->info(), output->info()));
+    ARM_COMPUTE_ERROR_THROW_ON(CLSoftmaxLayer::validate(input->info(), output->info(), beta, axis));
+
+    // We don't need flattening only in the case the input is 2D and axis is 1
+    _needs_flattening = axis != 1;
+
+    // If we are dealing with a 4D tensor, we will:
+    // - Flatten the input, so that we end up with a [width*height*depth] * batches 2D tensor
+    // - Execute all the pipeline (reduction + normalization) on the flattened tensor
+    // - Reshape the flattened output into the real output
+    if(_needs_flattening)
+    {
+        // Add to the memory manager _input_flattened
+        _memory_group.manage(&_input_flattened);
+
+        // Cofigure  _flatten_kernel and _input_flattened
+        configure_reshape_input_kernel(input, output, axis);
+    }
+
+    // We want to deal with a 2D input. Either it is the flattened version of the original input (4D case)
+    // or it is the original input case (2D case)
+    const ICLTensor *input_2D = (_needs_flattening ? &_input_flattened : input);
 
     // Create intermediate tensors shapes
-    const TensorInfo input_info    = input->info()->clone()->reset_padding().set_is_resizable(true);
-    DataType         tmp_data_type = is_data_type_quantized_asymmetric(input->info()->data_type()) ? DataType::S32 : input->info()->data_type();
-    TensorInfo       tensor_info_tmp(input_info.clone()->set_data_type(tmp_data_type));
+    TensorInfo input_info    = input_2D->info()->clone()->reset_padding().set_is_resizable(true);
+    DataType   tmp_data_type = is_data_type_quantized_asymmetric(input_2D->info()->data_type()) ? DataType::S32 : input_2D->info()->data_type();
+    TensorInfo tensor_info_tmp(input_info.clone()->set_data_type(tmp_data_type));
     _tmp.allocator()->init(tensor_info_tmp);
 
-    TensorShape max_sum_shape = input->info()->tensor_shape();
+    TensorShape max_sum_shape = input_2D->info()->tensor_shape();
     max_sum_shape.set(0, 1);
     _max.allocator()->init(input_info.clone()->set_tensor_shape(max_sum_shape));
     _sum.allocator()->init(input_info.clone()->set_tensor_shape(max_sum_shape).set_data_type(tmp_data_type));
@@ -65,8 +116,28 @@
     _memory_group.manage(&_sum);
 
     // Configure kernels
-    _max_shift_exp_sum_kernel.configure(input, &_max, &_tmp, &_sum, beta);
-    _norm_kernel.configure(&_tmp, &_sum, output, beta);
+    _max_shift_exp_sum_kernel.configure(input_2D, &_max, &_tmp, &_sum, beta);
+
+    if(_needs_flattening)
+    {
+        // Add to the memory manager _output_flattened
+        _memory_group.manage(&_output_flattened);
+
+        // The normalization kernel stores the result in a flat output tensor
+        _norm_kernel.configure(&_tmp, &_sum, &_output_flattened, beta);
+
+        // Reshape the flat output into a the requested (4D) output
+        _reshape_kernel.configure(&_output_flattened, output);
+
+        // Allocate the intermediate flat tensors
+        _input_flattened.allocator()->allocate();
+        _output_flattened.allocator()->allocate();
+    }
+    else
+    {
+        // Softmax 2D case
+        _norm_kernel.configure(&_tmp, &_sum, output, beta);
+    }
 
     // Allocate intermediate buffers
     _tmp.allocator()->allocate();
@@ -74,10 +145,11 @@
     _sum.allocator()->allocate();
 }
 
-Status CLSoftmaxLayer::validate(const ITensorInfo *input, const ITensorInfo *output)
+Status CLSoftmaxLayer::validate(const ITensorInfo *input, const ITensorInfo *output, float beta, size_t axis)
 {
     ARM_COMPUTE_RETURN_ERROR_ON_NULLPTR(input, output);
-    ARM_COMPUTE_RETURN_ERROR_ON_MSG(input->num_dimensions() > 2, "Only 2D inputs are supported");
+    ARM_COMPUTE_RETURN_ERROR_ON_MSG(input->num_dimensions() > 4, "Only up to 4 dimensions are supported");
+    ARM_COMPUTE_UNUSED(beta);
 
     // Create intermediate tensor info
     DataType   tmp_data_type = is_data_type_quantized_asymmetric(input->data_type()) ? DataType::S32 : input->data_type();
@@ -88,9 +160,32 @@
     TensorInfo tensor_info_max(input->clone()->set_tensor_shape(max_sum_shape).set_is_resizable(true));
     TensorInfo tensor_info_sum(input->clone()->set_tensor_shape(max_sum_shape).set_data_type(tmp_data_type).set_quantization_info(QuantizationInfo()).set_is_resizable(true));
 
+    const bool needs_flattening = (axis != 1);
+
+    if(needs_flattening)
+    {
+        const TensorShape shape_flatten = misc::shape_calculator::compute_softmax_shape(input, axis);
+        TensorInfo        tensor_info_flat(input->clone()->set_tensor_shape(shape_flatten).set_is_resizable(true));
+
+        if(axis != 3)
+        {
+            ARM_COMPUTE_RETURN_ON_ERROR(CLReshapeLayerKernel::validate(input, &tensor_info_flat));
+        }
+        else
+        {
+            ARM_COMPUTE_RETURN_ON_ERROR(CLFlattenLayerKernel::validate(input, &tensor_info_flat));
+        }
+    }
+
     ARM_COMPUTE_RETURN_ON_ERROR(CLLogits1DMaxShiftExpSumKernel::validate(input, &tensor_info_max, &tensor_info_tmp, &tensor_info_sum));
     ARM_COMPUTE_RETURN_ON_ERROR(CLLogits1DNormKernel::validate(&tensor_info_tmp, &tensor_info_sum, output));
 
+    if(needs_flattening)
+    {
+        const TensorShape shape_flatten = misc::shape_calculator::compute_softmax_shape(input);
+        TensorInfo        tensor_info_flat(input->clone()->set_tensor_shape(shape_flatten).set_is_resizable(true));
+    }
+
     return Status{};
 }
 
@@ -98,8 +193,21 @@
 {
     _memory_group.acquire();
 
-    CLScheduler::get().enqueue(_max_shift_exp_sum_kernel, false);
-    CLScheduler::get().enqueue(_norm_kernel);
+    if(_needs_flattening)
+    {
+        CLScheduler::get().enqueue(*_flatten_kernel_ptr, false);
+    }
 
+    CLScheduler::get().enqueue(_max_shift_exp_sum_kernel, false);
+    CLScheduler::get().enqueue(_norm_kernel, !_needs_flattening);
+
+    if(_needs_flattening)
+    {
+        CLScheduler::get().enqueue(_reshape_kernel, true);
+    }
+
+    // Relase intermediate buffers
     _memory_group.release();
 }
+
+} // namespace arm_compute