Decompose conv_2d -> conv_1d.
This MR follows a similar approach to https://reviews.llvm.org/D112928.
This patch adds support to convert conv_2D operation with either unit height or unit width to conv_1D operation.
This is useful when 2D convolution is tiled to have a single dimension for either height or width and then can be vectorized once it is decomposed into 1D convolution.
This patch https://reviews.llvm.org/D145160 adds vector support for linalg.conv_1d operation and thereby allowing us to vectorize linalg.conv_2d operation after proper tiling.
This missing feature is reported here: https://discourse.llvm.org/t/vectorization-of-convolution-op/60458.
Reviewed By: hanchung
Differential Revision: https://reviews.llvm.org/D145162
991945f441