[mlir][linalg] Implement TilingInterface for winograd operators

In order to support arbitrary size input data of conv2d, implement
TilingInterface for winograd operators. Before converting winograd
operators into nested loops with matrix multiply, tile the input of
conv2d into the supported size first.

Add a transform operator structured.decompose_winograd_op to decompose
winograd operators. Before applying the transform op, use tile_using_for
to tile the input data into supported size. The test case shows how to
tile and decompose winograd operators.

Author: Hsiangkai

mlir/include/mlir/Dialect/Linalg/IR/LinalgOps.td

@@ -154,7 +154,12 @@ def Linalg_SoftmaxOp : Linalg_Op<"softmax",
   let hasVerifier = 1;
 }
 
-def Linalg_WinogradFilterTransformOp : Linalg_Op<"winograd_filter_transform"> {
+def Linalg_WinogradFilterTransformOp : Linalg_Op<"winograd_filter_transform",
+    [DeclareOpInterfaceMethods<TilingInterface,
+     ["getIterationDomain",
+      "getLoopIteratorTypes",
+      "getResultTilePosition",
+      "getTiledImplementation"]>]> {
   let summary = "Winograd filter transform operator";
   let description = [{
     Winograd Conv2D algorithm will convert linalg Conv2D operator into batched
@@ -191,7 +196,12 @@ def Linalg_WinogradFilterTransformOp : Linalg_Op<"winograd_filter_transform"> {
   }];
 }
 
-def Linalg_WinogradInputTransformOp : Linalg_Op<"winograd_input_transform"> {
+def Linalg_WinogradInputTransformOp : Linalg_Op<"winograd_input_transform",
+    [DeclareOpInterfaceMethods<TilingInterface,
+      ["getIterationDomain",
+       "getLoopIteratorTypes",
+       "getResultTilePosition",
+       "getTiledImplementation"]>]> {
   let summary = "Winograd input transform operator";
   let description = [{
     Winograd Conv2D algorithm will convert linalg Conv2D operator into batched
@@ -228,7 +238,12 @@ def Linalg_WinogradInputTransformOp : Linalg_Op<"winograd_input_transform"> {
   }];
 }
 
-def Linalg_WinogradOutputTransformOp : Linalg_Op<"winograd_output_transform"> {
+def Linalg_WinogradOutputTransformOp : Linalg_Op<"winograd_output_transform",
+    [DeclareOpInterfaceMethods<TilingInterface,
+      ["getIterationDomain",
+       "getLoopIteratorTypes",
+       "getResultTilePosition",
+       "getTiledImplementation"]>]> {
   let summary = "Winograd output transform operator";
   let description = [{
     Winograd Conv2D algorithm will convert linalg Conv2D operator into batched

mlir/include/mlir/Dialect/Linalg/TransformOps/LinalgTransformOps.td

@@ -2638,4 +2638,41 @@ def WinogradConv2DOp : Op<Transform_Dialect,
   }];
 }
 
+def DecomposeWinogradOp : Op<Transform_Dialect,
+    "structured.decompose_winograd_op",
+    [FunctionalStyleTransformOpTrait, MemoryEffectsOpInterface,
+     TransformOpInterface, TransformEachOpTrait,
+     ReportTrackingListenerFailuresOpTrait]> {
+  let description = [{
+    Decompose winograd operators. It will convert filter, input and output
+    transform operators into a combination of scf, tensor, and linalg
+    equivalent operators. Before applying this transform operator, users
+    need to tile winograd transform operators into supported sizes.
+
+    #### Return modes:
+
+    This operation fails if `target` is unsupported. Otherwise, the operation
+    succeeds and returns a handle of the sequence that replaces the original
+    operator.
+  }];
+
+  let arguments = (ins TransformHandleTypeInterface:$target);
+  let results = (outs TransformHandleTypeInterface:$transformed);
+
+  let assemblyFormat =
+    "$target attr-dict `:` functional-type($target, results)";
+
+  let builders = [
+    OpBuilder<(ins "Value":$target)>
+  ];
+
+  let extraClassDeclaration = [{
+    ::mlir::DiagnosedSilenceableFailure applyToOne(
+        ::mlir::transform::TransformRewriter &rewriter,
+        ::mlir::Operation *target,
+        ::mlir::transform::ApplyToEachResultList &results,
+        ::mlir::transform::TransformState &state);
+  }];
+}
+
 #endif // LINALG_TRANSFORM_OPS

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

@@ -1319,6 +1319,51 @@ FailureOr<Operation *> winogradConv2D(RewriterBase &rewriter,
                                       linalg::Conv2DNhwcFhwcOp op, int64_t m,
                                       int64_t r);
 
+/// Rewrite linalg.winograd_filter_transform. The data layout of the filter is
+/// FHWC. The transformation matrix is 2-dimension. We need to extract H x W
+/// from FHWC first. We need to generate 2 levels of loops to iterate on F and
+/// C. After the rewriting, we get
+///
+/// scf.for %f = lo_f to hi_f step 1
+///   scf.for %c = lo_c to hi_c step 1
+///     %extracted = extract filter<h x w> from filter<f x h x w x c>
+///     %ret = linalg.matmul G, %extracted
+///     %ret = linalg.matmul %ret, GT
+///     %inserted = insert %ret into filter<h x w x c x f>
+FailureOr<Operation *>
+decomposeWinogradFilterTransformOp(RewriterBase &rewriter,
+                                   linalg::WinogradFilterTransformOp op);
+
+/// Rewrite linalg.winograd_input_transform. The data layout of the input is
+/// NHWC. The transformation matrix is 2-dimension. We need to extract H x W
+/// from NHWC first. We need to generate 2 levels of loops to iterate on N and
+/// C. After the rewriting, we get
+///
+/// scf.for %n = lo_n to hi_n step 1
+///   scf.for %c = lo_c to hi_c step 1
+///     %extracted = extract input<h x w> from input<n x h x w x c>
+///     %ret = linalg.matmul BT, %extracted
+///     %ret = linalg.matmul %ret, B
+///     %inserted = insert %ret into input<h x w x n x c>
+FailureOr<Operation *>
+decomposeWinogradInputTransformOp(RewriterBase &rewriter,
+                                  linalg::WinogradInputTransformOp op);
+
+/// Rewrite linalg.winograd_output_transform. The data layout of the output is
+/// HWNF. The transformation matrix is 2-dimension. We need to extract H x W
+/// from HWNF first. We need to generate 2 levels of loops to iterate on N and
+/// F. After the transformation, we get
+///
+/// scf.for %n = lo_n to hi_n step 1
+///   scf.for %f = lo_f to hi_f step 1
+///     %extracted = extract input<h x w> from result<h x w x n x f>
+///     %ret = linalg.matmul AT, %extracted
+///     %ret = linalg.matmul %ret, A
+///     %inserted = insert %ret into ret<n x h x w x f>
+FailureOr<Operation *>
+decomposeWinogradOutputTransformOp(RewriterBase &rewriter,
+                                   linalg::WinogradOutputTransformOp op);
+
 //===----------------------------------------------------------------------===//
 // Rewrite patterns wrapping transformations.
 // TODO: every single such pattern should be a close to noop wrapper around a