COMPMID-3339: Patch2: Remove paddings from im2col*_nhwc cl kernel

* Remove channel paddings from all nhwc kernels (im2col_3x3_nhwc,
  im2col_9x9_nhwc, im2col_generic_nhwc)
* Validate that input total spatial dimensions (with x and y paddings)
  are bigger than or equal to the kernel spatial dimension.
  - Otherwise it would result in invalid memory reads.
  - This problem likely existed before, but was made obvious with the
    removal of implicit paddings
* Add zero padding validation tests
* Fix Im2ColValidationFixture by not permuting the input shape in case of
  NHWC

Change-Id: I1f895e8938af0e9130cb516106f0b4b665531709
Signed-off-by: SiCong Li <sicong.li@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/3696
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Gian Marco Iodice <gianmarco.iodice@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>

1 files changed, 18 insertions, 6 deletions

diff --git a/src/core/CL/kernels/CLIm2ColKernel.cpp b/src/core/CL/kernels/CLIm2ColKernel.cpp
index de34ed384f..c94e313b9a 100644
--- a/src/core/CL/kernels/CLIm2ColKernel.cpp
+++ b/src/core/CL/kernels/CLIm2ColKernel.cpp
@@ -70,6 +70,13 @@ Status validate_arguments(const ITensorInfo *input, const ITensorInfo *output, c
     ARM_COMPUTE_RETURN_ERROR_ON(input->data_layout() == DataLayout::NHWC && num_groups > 1);
     ARM_COMPUTE_RETURN_ERROR_ON((input->dimension(channel_idx) % num_groups) != 0);
 
+    // Since there's no implicit padding added, check the total input spatial dimensions (with conv paddings) are big enough for the kernel dimensions
+    const unsigned int width_idx    = get_data_layout_dimension_index(input->data_layout(), DataLayoutDimension::WIDTH);
+    const unsigned int height_idx   = get_data_layout_dimension_index(input->data_layout(), DataLayoutDimension::HEIGHT);
+    const unsigned     total_width  = input->dimension(width_idx) + conv_info.pad_left() + conv_info.pad_right();
+    const unsigned     total_height = input->dimension(height_idx) + conv_info.pad_top() + conv_info.pad_bottom();
+    ARM_COMPUTE_RETURN_ERROR_ON((total_width < kernel_dims.width) || (total_height < kernel_dims.height));
+
     if(output->total_size() > 0)
     {
         const TensorInfo tensor_info_output = output->clone()->set_tensor_shape(compute_im2col_conv_shape(input, kernel_dims, conv_info, has_bias, dilation, num_groups == 1, num_groups));
@@ -106,12 +113,12 @@ std::pair<Status, Window> validate_and_configure_window(ITensorInfo *input, ITen
         win = calculate_max_window(*input, Steps(num_elems_processed_per_iteration));
 
         const int xin_start = 0;
-        const int xin_end   = input->dimension(0) < num_elems_processed_per_iteration ? ceil_to_multiple(input->dimension(0), num_elems_processed_per_iteration) : input->dimension(0);
+        const int xin_end   = input->dimension(0);
         const int yin_start = 0;
         const int yin_end   = input->dimension(1);
 
         const int xout_start = 0;
-        const int xout_end   = input->dimension(0) < num_elems_processed_per_iteration ? output->dimension(0) + (num_elems_processed_per_iteration - input->dimension(0)) : output->dimension(0);
+        const int xout_end   = output->dimension(0);
         const int yout_start = 0;
         const int yout_end   = output->dimension(1);
 
@@ -140,7 +147,6 @@ std::pair<Status, Window> validate_and_configure_window(ITensorInfo *input, ITen
             win = calculate_max_window(*input, Steps());
         }
     }
-
     output->set_valid_region(ValidRegion(Coordinates(), output->tensor_shape()));
     // set the Z dimension's step same size as the whole dimension so that one can't split across the Z dimension
     win.set_dimension_step(Window::DimZ, win[Window::DimZ].end() - win[Window::DimZ].start());
@@ -192,7 +198,7 @@ Im2ColConfiguration configure_opencl_kernel(const ITensorInfo *input, const Size
 
     if(data_layout == DataLayout::NHWC)
     {
-        num_elems_processed_per_iteration = 2;
+        num_elems_processed_per_iteration = std::min(2U, input_channel);
         is_padding_required_nchw          = false;
 
         // Only the 3x3 and 9x9 cases are optimized for NHWC
@@ -205,8 +211,14 @@ Im2ColConfiguration configure_opencl_kernel(const ITensorInfo *input, const Size
             kernel_name = "im2col9x9_";
         }
 
-        build_opts.add_option("-DVECTOR_SIZE=" + support::cpp11::to_string(num_elems_processed_per_iteration));
-        build_opts.add_option("-DLAST_ACCESSED=" + support::cpp11::to_string(std::max(static_cast<int>(input_channel - num_elems_processed_per_iteration), 0)));
+        // Get boundary vector (the first/last vector with potentially a partial vector size) size
+        // If input_channel is a multiple of num_elems_processed_per_iteration, the boundary vec size is the (full) vector size
+        // otherwise, the boundary vec size is the (partial) remainder vector size
+        const unsigned int vec_size          = num_elems_processed_per_iteration;
+        const unsigned int partial_vec_size  = input_channel % vec_size;
+        const unsigned int boundary_vec_size = vec_size - ((vec_size - partial_vec_size) % vec_size);
+        build_opts.add_option("-DVECTOR_SIZE=" + support::cpp11::to_string(vec_size));
+        build_opts.add_option("-DBOUNDARY_VECTOR_SIZE=" + support::cpp11::to_string(boundary_vec_size));
     }
     else
     {