[Mlir-commits] [mlir] Fold `linalg.fill` -> `linalg.copy` along `outs` use in the consumer. (PR #72920)

[llvmlistbot at llvm.org]

https://github.com/MaheshRavishankar updated https://github.com/llvm/llvm-project/pull/72920

>From ca09afe76b7ce69e3ec0316d0442daf5c2f61683 Mon Sep 17 00:00:00 2001
From: MaheshRavishankar <mahesh.ravishankar at gmail.com>
Date: Wed, 8 Nov 2023 13:40:37 -0700
Subject: [PATCH] Fold `linalg.fill` -> `linalg.copy` along `outs` use in the
 consumer.

---
 mlir/lib/Dialect/Linalg/IR/LinalgOps.cpp   | 24 ++++++++++++++++++----
 mlir/test/Dialect/Linalg/canonicalize.mlir | 13 ++++++++++++
 2 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/mlir/lib/Dialect/Linalg/IR/LinalgOps.cpp b/mlir/lib/Dialect/Linalg/IR/LinalgOps.cpp
index d12ba8c4c59b33f..24d29d299ab2418 100644
--- a/mlir/lib/Dialect/Linalg/IR/LinalgOps.cpp
+++ b/mlir/lib/Dialect/Linalg/IR/LinalgOps.cpp
@@ -803,14 +803,30 @@ struct FoldFillWithPack : public OpRewritePattern<tensor::PackOp> {
   }
 };
 
+/// Fold fill with copy.
+struct FoldFillWithCopy : OpRewritePattern<linalg::CopyOp> {
+  using OpRewritePattern<linalg::CopyOp>::OpRewritePattern;
+
+  LogicalResult matchAndRewrite(linalg::CopyOp copyOp,
+                                PatternRewriter &rewriter) const override {
+    auto fillOp = copyOp.getOutputs().front().getDefiningOp<FillOp>();
+    if (!fillOp)
+      return failure();
+    rewriter.replaceOpWithNewOp<linalg::CopyOp>(copyOp, copyOp.getInputs(),
+                                                fillOp.getOutputs());
+    return success();
+  }
+};
+
 } // namespace
 
 void FillOp::getCanonicalizationPatterns(RewritePatternSet &results,
                                          MLIRContext *context) {
-  results.add<FoldFillWithTensorExtract, FoldFillWithPack, FoldFillWithPad,
-              FoldFillWithTensorReshape<tensor::CollapseShapeOp>,
-              FoldFillWithTensorReshape<tensor::ExpandShapeOp>,
-              FoldInsertPadIntoFill>(context);
+  results
+      .add<FoldFillWithCopy, FoldFillWithTensorExtract, FoldFillWithPack,
+           FoldFillWithPad, FoldFillWithTensorReshape<tensor::CollapseShapeOp>,
+           FoldFillWithTensorReshape<tensor::ExpandShapeOp>,
+           FoldInsertPadIntoFill>(context);
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/mlir/test/Dialect/Linalg/canonicalize.mlir b/mlir/test/Dialect/Linalg/canonicalize.mlir
index 7793e435582746c..c054829a915d7ba 100644
--- a/mlir/test/Dialect/Linalg/canonicalize.mlir
+++ b/mlir/test/Dialect/Linalg/canonicalize.mlir
@@ -972,3 +972,16 @@ func.func @canonicalize_dim_of_dest_style_op(%arg0 : tensor<?x?xf32>) -> tensor<
   %3 = linalg.copy ins(%1 : tensor<?x?xf32>) outs(%2 : tensor<?x?xf32>) -> tensor<?x?xf32>
   return %3: tensor<?x?xf32>
 }
+
+// -----
+
+// CHECK-LABEL: func @canonicalize_fill_to_copy_dest(
+//  CHECK-SAME:     %[[ARG0:[a-zA-Z0-9]+]]: tensor<?x?xf32>
+//  CHECK-SAME:     %[[ARG1:[a-zA-Z0-9]+]]: tensor<?x?xf32>)
+//       CHECK:   linalg.copy ins(%[[ARG1]] : tensor<?x?xf32>) outs(%[[ARG0]] : tensor<?x?xf32>)
+func.func @canonicalize_fill_to_copy_dest(%arg0 : tensor<?x?xf32>, %arg1 : tensor<?x?xf32>) -> tensor<?x?xf32> {
+  %c0 = arith.constant 0.0 : f32
+  %fill = linalg.fill ins(%c0 : f32) outs(%arg0 : tensor<?x?xf32>) -> tensor<?x?xf32>
+  %copy = linalg.copy ins(%arg1 : tensor<?x?xf32>) outs(%fill : tensor<?x?xf32>) -> tensor<?x?xf32>
+  return %copy : tensor<?x?xf32>
+}