[mlir][linalg] Explicitly instantiate DownscaleSizeOneWindowed2DConvolution

It's not possible to use a template with no definition from another
translation unit. Fixes the shared library build.

Author: d0k

mlir/include/mlir/Dialect/Linalg/Transforms/Transforms.h

@@ -776,6 +776,11 @@ struct DownscaleSizeOneWindowed2DConvolution final
   LinalgTransformationFilter filter;
 };
 
+extern template struct DownscaleSizeOneWindowed2DConvolution<Conv2DNhwcHwcfOp,
+                                                             Conv1DNwcWcfOp>;
+extern template struct DownscaleSizeOneWindowed2DConvolution<Conv2DNchwFchwOp,
+                                                             Conv1DNcwFcwOp>;
+
 /// Rewrites 2-D depthwise convolution ops with size-1 (w, kw) or (h, kh)
 /// dimensions into 1-D depthwise convolution ops.
 struct DownscaleDepthwiseConv2DNhwcHwcOp final

mlir/lib/Dialect/Linalg/Transforms/Transforms.cpp

@@ -920,6 +920,11 @@ FailureOr<Conv1DOp> DownscaleSizeOneWindowed2DConvolution<Conv2DOp, Conv1DOp>::
   return conv1DOp;
 }
 
+template struct linalg::DownscaleSizeOneWindowed2DConvolution<Conv2DNhwcHwcfOp,
+                                                              Conv1DNwcWcfOp>;
+template struct linalg::DownscaleSizeOneWindowed2DConvolution<Conv2DNchwFchwOp,
+                                                              Conv1DNcwFcwOp>;
+
 FailureOr<DepthwiseConv1DNwcWcOp>
 DownscaleDepthwiseConv2DNhwcHwcOp::returningMatchAndRewrite(
     DepthwiseConv2DNhwcHwcOp convOp, PatternRewriter &rewriter) const {