Im2col for convolution

Can we choose convolution algorithm to perform conv2d? At present, “direct” is the defualt setting, can we use im2col->gemm?

You should implement im2col schedule firstly.

For 1x1 conv,maybe it’s better to use gemm instead of direct conv.
But utn, tvm don’t have efficient gemm implementation on arm. x86 dense would not the best chioce.