Remove padding from direct convolution - OpenCL

- Refactor direct convolution for NHWC
- Remove old kernels for NHWC
- Change the heuristic in CLConvolutionLayer.cpp. The new direct
  convolution implementation is faster than FFT

Resolves COMPMID-3908

Change-Id: Iee15ce7b04e21847b6eaae5c6d3c1b18180e7efc
Signed-off-by: Gian Marco Iodice <gianmarco.iodice@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/4876
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
diff --git a/src/core/CL/cl_kernels/direct_convolution1x1.cl b/src/core/CL/cl_kernels/direct_convolution1x1.cl
index d0eea5b..8ab2d1d 100644
--- a/src/core/CL/cl_kernels/direct_convolution1x1.cl
+++ b/src/core/CL/cl_kernels/direct_convolution1x1.cl
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2018 Arm Limited.
+ * Copyright (c) 2016-2021 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -31,122 +31,6 @@
 
 #if defined(DATA_TYPE) && defined(DATA_SIZE) && defined(STRIDE_X) && defined(WEIGHTS_DEPTH)
 
-#if defined(DATA_LAYOUT_NHWC)
-
-#define PTR_TO_VALUE(PTR, DATA_TYPE) *((__global DATA_TYPE *)(PTR))
-
-/** This kernel performs a direct convolution to convolve the low three dimensions of a tensor with data layout NHWC
- *
- * @note The data type must be passed at compile time using -DDATA_TYPE: e.g. -DDATA_TYPE=float
- * @note The data size must be passed at compile time using -DDATA_SIZE e.g. -DDATA_SIZE=32
- * @note The convolution stride x must be passed at compile time using -DSTRIDE_X e.g. -DSTRIDE_X=1
- * @note The third dimensions of the weights tensors must be passed at compile time using -DWEIGHTS_DEPTH
- * @note In case biases will be added to the convolution -DHAS_BIAS has to be passed to append the final matrix with 1 in each row.
- *
- * @param[in]  src_ptr                               Pointer to the source tensor. Supported data types: F16/F32
- * @param[in]  src_stride_x                          Stride of the source tensor in X dimension (in bytes)
- * @param[in]  src_step_x                            src_stride_x * number of elements along X processed per workitem(in bytes)
- * @param[in]  src_stride_y                          Stride of the source tensor in Y dimension (in bytes)
- * @param[in]  src_step_y                            src_stride_y * number of elements along Y processed per workitem(in bytes)
- * @param[in]  src_stride_z                          Stride of the source tensor in Z dimension (in bytes)
- * @param[in]  src_step_z                            src_stride_z * number of elements along Z processed per workitem(in bytes)
- * @param[in]  src_offset_first_element_in_bytes     The offset of the first element in the source tensor
- * @param[out] dst_ptr                               Pointer to the destination tensor. Supported data types: same as @p src_ptr
- * @param[in]  dst_stride_x                          Stride of the destination tensor in X dimension (in bytes)
- * @param[in]  dst_step_x                            dst_stride_x * number of elements along X processed per workitem(in bytes)
- * @param[in]  dst_stride_y                          Stride of the destination tensor in Y dimension (in bytes)
- * @param[in]  dst_step_y                            dst_stride_y * number of elements along Z processed per workitem(in bytes)
- * @param[in]  dst_stride_z                          Stride of the destination tensor in Z dimension (in bytes)
- * @param[in]  dst_step_z                            dst_stride_z * number of elements along Z processed per workitem(in bytes)
- * @param[in]  dst_offset_first_element_in_bytes     The offset of the first element in the destination tensor
- * @param[in]  weights_ptr                           Pointer to the weights tensor. Supported data types: same as @p src_ptr
- * @param[in]  weights_stride_x                      Stride of the weights tensor in X dimension (in bytes)
- * @param[in]  weights_step_x                        weights_stride_x * number of elements along X processed per workitem(in bytes)
- * @param[in]  weights_stride_y                      Stride of the weights tensor in Y dimension (in bytes)
- * @param[in]  weights_step_y                        weights_stride_y * number of elements along y processed per workitem(in bytes)
- * @param[in]  weights_stride_z                      Stride of the weights tensor in Z dimension (in bytes)
- * @param[in]  weights_step_z                        weights_stride_z * number of elements along Z processed per workitem(in bytes)
- * @param[in]  weights_offset_first_element_in_bytes The offset of the first element in the weights tensor
- * @param[in]  biases_ptr                            Pointer to the biases tensor. Same as @p src_ptr
- * @param[in]  biases_stride_x                       Stride of the biases tensor in X dimension (in bytes)
- * @param[in]  biases_step_x                         biases_stride_x * number of elements along X processed per workitem(in bytes)
- * @param[in]  biases_offset_first_element_in_bytes  The offset of the first element in the biases tensor
- * @param[in]  weights_stride_w                      Stride of the weights tensor in the 4th dimension
- */
-__kernel void direct_convolution1x1_nhwc(
-    TENSOR3D_DECLARATION(src),
-    TENSOR3D_DECLARATION(dst),
-    TENSOR3D_DECLARATION(weights),
-#ifdef HAS_BIAS
-    VECTOR_DECLARATION(biases),
-#endif /* defined(HAS_BIAS) */
-    unsigned int weights_stride_w)
-{
-    Image    src     = CONVERT_TO_IMAGE_STRUCT(src);
-    Tensor3D weights = CONVERT_TO_TENSOR3D_STRUCT_NO_STEP(weights);
-    Tensor3D dst     = CONVERT_TO_TENSOR3D_STRUCT(dst);
-
-#ifdef HAS_BIAS
-    Vector biases = CONVERT_TO_VECTOR_STRUCT_NO_STEP(biases);
-#endif /* defined(HAS_BIAS) */
-
-    VEC_DATA_TYPE(DATA_TYPE_PROMOTED, 8)
-    values        = 0;
-    const int id0 = get_global_id(0);
-    const int id1 = get_global_id(1);
-    const int id2 = get_global_id(2);
-    weights.ptr += id0 * weights_stride_w;
-    __global uchar *src_addr = (__global uchar *)offset(&src, 0, 0) - src_stride_x * id0 + id2 * STRIDE_Y * (int)src_stride_z;
-
-    for(volatile int d = 0; d < WEIGHTS_DEPTH; ++d)
-    {
-        DATA_TYPE weight = *(__global DATA_TYPE *)weights.ptr;
-#if STRIDE_X == 1
-        VEC_DATA_TYPE(DATA_TYPE, 8)
-        col0 = (VEC_DATA_TYPE(DATA_TYPE, 8))(
-                   PTR_TO_VALUE(src_addr + 0 * src_stride_y, DATA_TYPE),
-                   PTR_TO_VALUE(src_addr + 1 * src_stride_y, DATA_TYPE),
-                   PTR_TO_VALUE(src_addr + 2 * src_stride_y, DATA_TYPE),
-                   PTR_TO_VALUE(src_addr + 3 * src_stride_y, DATA_TYPE),
-                   PTR_TO_VALUE(src_addr + 4 * src_stride_y, DATA_TYPE),
-                   PTR_TO_VALUE(src_addr + 5 * src_stride_y, DATA_TYPE),
-                   PTR_TO_VALUE(src_addr + 6 * src_stride_y, DATA_TYPE),
-                   PTR_TO_VALUE(src_addr + 7 * src_stride_y, DATA_TYPE));
-#elif STRIDE_X == 2 /* STRIDE_X == 1 */
-        VEC_DATA_TYPE(DATA_TYPE, 8)
-        col0 = (VEC_DATA_TYPE(DATA_TYPE, 8))(
-                   PTR_TO_VALUE(src_addr + 0 * src_stride_y, DATA_TYPE),
-                   PTR_TO_VALUE(src_addr + 2 * src_stride_y, DATA_TYPE),
-                   PTR_TO_VALUE(src_addr + 4 * src_stride_y, DATA_TYPE),
-                   PTR_TO_VALUE(src_addr + 6 * src_stride_y, DATA_TYPE),
-                   PTR_TO_VALUE(src_addr + 8 * src_stride_y, DATA_TYPE),
-                   PTR_TO_VALUE(src_addr + 10 * src_stride_y, DATA_TYPE),
-                   PTR_TO_VALUE(src_addr + 12 * src_stride_y, DATA_TYPE),
-                   PTR_TO_VALUE(src_addr + 14 * src_stride_y, DATA_TYPE));
-#else               /* STRIDE_X not equals 1 or 2 */
-#error "STRIDE_X larger than 2 is not supported"
-#endif /* STRIDE_X == 2 */
-        values = ADD_OP(values, MUL_OP((VEC_DATA_TYPE(DATA_TYPE, 8))weight, col0));
-
-        src_addr += src_stride_x;
-        weights.ptr += weights_stride_x;
-    }
-
-#ifdef HAS_BIAS
-    values = ADD_OP(values, (VEC_DATA_TYPE(DATA_TYPE_PROMOTED, 8)) * ((__global DATA_TYPE *)(vector_offset(&biases, id0))));
-#endif /* defined(HAS_BIAS) */
-
-    *((__global DATA_TYPE *)dst.ptr)                      = values.s0;
-    *((__global DATA_TYPE *)(dst.ptr + 1 * dst_stride_y)) = values.s1;
-    *((__global DATA_TYPE *)(dst.ptr + 2 * dst_stride_y)) = values.s2;
-    *((__global DATA_TYPE *)(dst.ptr + 3 * dst_stride_y)) = values.s3;
-    *((__global DATA_TYPE *)(dst.ptr + 4 * dst_stride_y)) = values.s4;
-    *((__global DATA_TYPE *)(dst.ptr + 5 * dst_stride_y)) = values.s5;
-    *((__global DATA_TYPE *)(dst.ptr + 6 * dst_stride_y)) = values.s6;
-    *((__global DATA_TYPE *)(dst.ptr + 7 * dst_stride_y)) = values.s7;
-}
-#endif // defined(DATA_LAYOUT_NHWC)
-
 #if STRIDE_X == 3
 #define INPUT_PIXEL_STR(data_size) extract_input_stride3_##data_size
 #define INPUT_PIXEL(data_size) INPUT_PIXEL_STR(data_size)