COMPMID-1277 - Optimizing CLIm2ColKernel for NHWC.

This patch includes:

- Im2Col optimizations for NHWC using a new data layout
- Refactoring of CLIm2ColKernel adding validation method and auto-init
- Removed im2col_reduced from CLIm2ColKernel and created a new kernel CLFlattenLayerKernel

Change-Id: I1620640b6796baa268324b33ae92cdd8de53e27c
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/141241
Tested-by: Jenkins <bsgcomp@arm.com>
Reviewed-by: Giorgio Arena <giorgio.arena@arm.com>

3 files changed, 78 insertions, 38 deletions

diff --git a/arm_compute/core/CL/CLKernels.h b/arm_compute/core/CL/CLKernels.h
index 737d8df4e8..ea942bde5d 100644
--- a/arm_compute/core/CL/CLKernels.h
+++ b/arm_compute/core/CL/CLKernels.h
@@ -62,6 +62,7 @@
 #include "arm_compute/core/CL/kernels/CLErodeKernel.h"
 #include "arm_compute/core/CL/kernels/CLFastCornersKernel.h"
 #include "arm_compute/core/CL/kernels/CLFillBorderKernel.h"
+#include "arm_compute/core/CL/kernels/CLFlattenLayerKernel.h"
 #include "arm_compute/core/CL/kernels/CLFloorKernel.h"
 #include "arm_compute/core/CL/kernels/CLGEMMInterleave4x4Kernel.h"
 #include "arm_compute/core/CL/kernels/CLGEMMLowpMatrixMultiplyKernel.h"
diff --git a/arm_compute/core/CL/kernels/CLFlattenLayerKernel.h b/arm_compute/core/CL/kernels/CLFlattenLayerKernel.h
new file mode 100644
index 0000000000..a5cf6e0c33
--- /dev/null
+++ b/arm_compute/core/CL/kernels/CLFlattenLayerKernel.h
@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2018 ARM Limited.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef __ARM_COMPUTE_CLFLATTENLAYERKERNEL_H__
+#define __ARM_COMPUTE_CLFLATTENLAYERKERNEL_H__
+
+#include "arm_compute/core/CL/ICLKernel.h"
+
+namespace arm_compute
+{
+class ICLTensor;
+
+/** OpenCL interface for the flatten kernel.*/
+class CLFlattenLayerKernel : public ICLKernel
+{
+public:
+    /** Default constructor */
+    CLFlattenLayerKernel();
+    /** Prevent instances of this class from being copied (As this class contains pointers) */
+    CLFlattenLayerKernel(const CLFlattenLayerKernel &) = delete;
+    /** Prevent instances of this class from being copied (As this class contains pointers) */
+    CLFlattenLayerKernel &operator=(const CLFlattenLayerKernel &) = delete;
+    /** Allow instances of this class to be moved */
+    CLFlattenLayerKernel(CLFlattenLayerKernel &&) = default;
+    /** Allow instances of this class to be moved */
+    CLFlattenLayerKernel &operator=(CLFlattenLayerKernel &&) = default;
+    /** Set the input and output of the kernel.
+     *
+     * @param[in]  input  First input tensor to flatten with at least 3 dimensions.
+     *                    The dimensions above the third will be interpreted as batches. Data types supported: U8/S8/QASYMM8/U16/S16/F16/U32/S32/F32
+     * @param[out] output Output tensor with shape [w*h*d, input_batches] where:
+     *                    w = width input tensor, h = height input tensor and d = depth input tensor. Data type supported: same as @p input
+     */
+    void configure(const ICLTensor *input, ICLTensor *output);
+    /** Static function to check if given info will lead to a valid configuration of @ref CLFlattenLayerKernel
+     *
+     * @param[in]  input  First input tensor to flatten with at least 3 dimensions.
+     *                    The dimensions above the third will be interpreted as batches. Data types supported: U8/S8/QASYMM8/U16/S16/F16/U32/S32/F32
+     * @param[out] output Output tensor with shape [w*h*d, input_batches] where:
+     *                    w = width input tensor, h = height input tensor and d = depth input tensor. Data type supported: same as @p input
+     *
+     * @return a status
+     */
+    static Status validate(const ITensorInfo *input, const ITensorInfo *output);
+
+    // Inherited methods overridden:
+    void run(const Window &window, cl::CommandQueue &queue) override;
+
+public:
+    const ICLTensor *_input;
+    ICLTensor       *_output;
+};
+} // namespace arm_compute
+#endif /*__ARM_COMPUTE_CLFLATTENLAYERKERNEL_H__ */
diff --git a/arm_compute/core/CL/kernels/CLIm2ColKernel.h b/arm_compute/core/CL/kernels/CLIm2ColKernel.h
index fc930abcbe..ae19319047 100644
--- a/arm_compute/core/CL/kernels/CLIm2ColKernel.h
+++ b/arm_compute/core/CL/kernels/CLIm2ColKernel.h
@@ -96,48 +96,13 @@ public:
     // Inherited methods overridden:
     void run(const Window &window, cl::CommandQueue &queue) override;
 
-private:
-    /** Run the reshape kernel optimised for the special case (stride is 1, padding is 0 and kernel's low 3 dimensions are same as input)
-     *
-     * @param[in]     window Region on which to execute the kernel. (Must be a valid region of the window returned by window()).
-     * @param[in,out] queue  Command queue on which to enqueue the kernel.
-     */
-    void run_reduced(const Window &window, cl::CommandQueue &queue);
-    /** run the generic convolution layer input reshape kernel
-     *
-     * @param[in]     window Region on which to execute the kernel. (Must be a valid region of the window returned by window()).
-     * @param[in,out] queue  Command queue on which to enqueue the kernel.
-     */
-    void run_generic(const Window &window, cl::CommandQueue &queue);
-
-    /** Chooses and configure the right kernel for the given input arguments.
-     *
-     * @param[in]  input       The input tensor to convert. 3 lower dimensions represent a single input [width, height, IFM],
-     *                         while every optional dimension from 4 and above represent a batch of inputs. Data types supported: QASYMM8/F16/F32
-     * @param[in]  output      The output tensor. First 2 lower dimensions represent a transform of each 3D input,
-     *                         while every dimension above represents a batch. Data types supported: Same as @p input
-     * @param[in]  kernel_dims The kernel dimensions (width and height).
-     * @param[in]  dilation    Dilation, in elements, across x and y. Defaults to (1, 1).
-     * @param[in]  conv_info   Contains padding and stride information described in @ref PadStrideInfo.
-     * @param[in]  has_bias    In case biases are provided expands the matrix with 1.
-     * @param[out] build_opts  OpenCL buil program options.
-     *
-     * @return the name of the kernel chosen
-     */
-    std::string configure_window(const ICLTensor *input, ICLTensor *output, const Size2D &kernel_dims,
-                                 const Size2D &dilation, const PadStrideInfo &conv_info, CLBuildOptions &build_opts);
-
-    /** Common signature for the kernel to run */
-    using Im2ColFunction = void (CLIm2ColKernel::*)(const Window &, cl::CommandQueue &);
-
 public:
     const ICLTensor *_input;
     ICLTensor       *_output;
-    PadStrideInfo    _conv_info;
     std::pair<unsigned int, unsigned int> _convolved_dims;
-    unsigned int   _num_elems_processed_per_iteration;
-    Im2ColFunction _run_func;
-    Size2D         _kernel_dims;
+    unsigned int  _num_elems_processed_per_iteration;
+    Size2D        _kernel_dims;
+    PadStrideInfo _conv_info;
 };
 } // namespace arm_compute
 #endif /*__ARM_COMPUTE_CLIM2COLKERNEL_H__ */