Port the ClGemmLowp kernels to the new API

Ported kernels:
 - CLGEMMLowpMatrixMultiplyNativeKernel
 - CLGEMMLowpMatrixMultiplyReshapedKernel
 - CLGEMMLowpMatrixMultiplyReshapedOnlyRHSKernel
 - CLGEMMLowpOffsetContributionKernel
 - CLGEMMLowpOffsetContributionOutputStageKernel
 - CLGEMMLowpQuantizeDownInt32ScaleByFixedPointKernel
 - CLGEMMLowpQuantizeDownInt32ScaleByFloatKernel
 - CLGEMMLowpQuantizeDownInt32ScaleKernel

Signed-off-by: Georgios Pinitas <georgios.pinitas@arm.com>
Change-Id: I9d5a744d6a2dd2f2726fdfb291bad000b6970de2
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/5870
Reviewed-by: Michele Di Giorgio <michele.digiorgio@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
diff --git a/src/core/gpu/cl/kernels/ClGemmLowpReductionKernel.h b/src/core/gpu/cl/kernels/ClGemmLowpReductionKernel.h
new file mode 100644
index 0000000..11188ed
--- /dev/null
+++ b/src/core/gpu/cl/kernels/ClGemmLowpReductionKernel.h
@@ -0,0 +1,124 @@
+/*
+ * Copyright (c) 2017-2021 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_CL_GEMMLOWP_REDUCTION_KERNEL_H
+#define ARM_COMPUTE_CL_GEMMLOWP_REDUCTION_KERNEL_H
+
+#include "arm_compute/core/KernelDescriptors.h"
+#include "src/core/common/Macros.h"
+#include "src/core/gpu/cl/ClCompileContext.h"
+#include "src/core/gpu/cl/IClKernel.h"
+
+namespace arm_compute
+{
+namespace opencl
+{
+namespace kernels
+{
+/** Common interface for all OpenCL reduction kernels */
+class IClGemmLowpReductionKernel : public IClKernel
+{
+public:
+    IClGemmLowpReductionKernel();
+    ARM_COMPUTE_DISALLOW_COPY_ALLOW_MOVE(IClGemmLowpReductionKernel);
+    /** Initialise the kernel's input and output.
+     *
+     * @param[in]  compile_context The compile context to be used.
+     * @param[in]  input           Input tensor. Data type supported: QASYMM8/QASYMM8_SIGNED/QSYMM8.
+     * @param[out] output          Output row-vector of sums of all the entries in each row/col of input tensor. Data type supported: S32
+     * @param[in]  info            Kernel metadata:
+     *                             - k            Number of matrix columns/rows depending on the type of reduction.
+     *                             - is_reshaped  True if the matrix has been reshaped.
+     *                             - scalar       Scalar value to multiply each reduced column/row by.
+     *                             - mul_byscalar True if each reduced column/row must be multiplied by a scalar value.
+     */
+    virtual void configure(const CLCompileContext &compile_context, const ITensorInfo *input, ITensorInfo *output, const GEMMLowpReductionKernelInfo &info) = 0;
+};
+
+/** OpenCL kernel used to compute the row-vectors of sums of all the entries in each row of Matrix A.
+ *
+ * @note This stage is needed to handle the offset of matrix product
+ *       https://github.com/google/gemmlowp/blob/master/doc/low-precision.md
+ */
+class ClGemmLowpMatrixAReductionKernel : public IClGemmLowpReductionKernel
+{
+public:
+    /** Initialise the kernel's input and output.
+     *
+     * @param[in]  compile_context The compile context to be used.
+     * @param[in]  mtx_a           Input tensor. Data type supported: QASYMM8/QASYMM8_SIGNED/QSYMM8.
+     * @param[out] vector_sum_row  Output row-vector of sums of all the entries in each row of mtx_a. Data type supported: S32
+     * @param[in]  info            Kernel metadata:
+     *                             - k            Number of matrix columns/rows depending on the type of reduction.
+     *                             - is_reshaped  True if the matrix has been reshaped.
+     *                             - scalar       Scalar value to multiply each reduced column/row by.
+     *                             - mul_byscalar True if each reduced column/row must be multiplied by a scalar value.
+     */
+    void configure(const CLCompileContext &compile_context, const ITensorInfo *mtx_a, ITensorInfo *vector_sum_row, const GEMMLowpReductionKernelInfo &info) override;
+    /** Static function to check if given info will lead to a valid configuration
+     *
+     * Similar to @ref ClGemmLowpQuantizeDownInt32ScaleByFixedPointKernel::configure()
+     *
+     * @return a status
+     */
+    static Status validate(const ITensorInfo *mtx_a, const ITensorInfo *vector_sum_row, const GEMMLowpReductionKernelInfo &info);
+
+    // Inherited methods overridden:
+    void run_op(ITensorPack &tensors, const Window &window, cl::CommandQueue &queue) override;
+};
+
+/** OpenCL kernel used to compute the row-vectors of sums of all the entries in each column of Matrix B.
+ *
+ * @note This stage is needed to handle the offset of matrix product
+ *       https://github.com/google/gemmlowp/blob/master/doc/low-precision.md
+ */
+class ClGemmLowpMatrixBReductionKernel : public IClGemmLowpReductionKernel
+{
+public:
+    /** Initialise the kernel's input and output.
+     *
+     * @param[in]  compile_context The compile context to be used.
+     * @param[in]  mtx_b           Input tensor. Data type supported: Data type supported: QASYMM8/QASYMM8_SIGNED/QSYMM8/QSYMM8_PER_CHANNEL.
+     * @param[out] vector_sum_col  Output row-vector of sums of all the entries in each column of mtx_b. Data type supported: S32
+     * @param[in]  info            Kernel metadata:
+     *                             - k            Number of matrix columns/rows depending on the type of reduction.
+     *                             - is_reshaped  True if the matrix has been reshaped.
+     *                             - scalar       Scalar value to multiply each reduced column/row by.
+     *                             - mul_byscalar True if each reduced column/row must be multiplied by a scalar value.
+     */
+    void configure(const CLCompileContext &compile_context, const ITensorInfo *mtx_b, ITensorInfo *vector_sum_col, const GEMMLowpReductionKernelInfo &info) override;
+    /** Static function to check if given info will lead to a valid configuration
+     *
+     * Similar to @ref ClGemmLowpQuantizeDownInt32ScaleByFixedPointKernel::configure()
+     *
+     * @return a status
+     */
+    static Status validate(const ITensorInfo *mtx_b, const ITensorInfo *vector_sum_col, const GEMMLowpReductionKernelInfo &info);
+
+    // Inherited methods overridden:
+    void run_op(ITensorPack &tensors, const Window &window, cl::CommandQueue &queue) override;
+};
+} // namespace kernels
+} // namespace opencl
+} // namespace arm_compute
+#endif /* ARM_COMPUTE_CL_GEMMLOWP_REDUCTION_KERNEL_H */