[Mlir-commits] [mlir] [mlir][x86vector] Lower vector.contract to FMA or packed type dot-product (PR #168074)

Adam Siemieniuk llvmlistbot at llvm.org
Tue Nov 18 10:43:22 PST 2025


================
@@ -0,0 +1,99 @@
+//===- VectorContractToFMA.cpp --------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Dialect/Vector/IR/VectorOps.h"
+#include "mlir/Dialect/Vector/Utils/VectorUtils.h"
+#include "mlir/Dialect/X86Vector/Transforms.h"
+#include "mlir/Dialect/X86Vector/X86VectorDialect.h"
+
+#include "mlir/IR/BuiltinAttributes.h"
+#include "mlir/IR/Dominance.h"
+#include "mlir/IR/PatternMatch.h"
+
+#include "mlir/Pass/Pass.h"
+#include "mlir/Transforms/GreedyPatternRewriteDriver.h"
+
+using namespace mlir;
+using namespace mlir::vector;
+using namespace mlir::x86vector;
+
+// Implements outer product contraction as a sequence of broadcast and
+// FMA operations.
+//
+// For example - for F32 type:
+// ```
+//   vector.contract <1x1xf32>, <1x16xf32> into <1x16xf32>
+// ```
+// to
+// ```
+//   vector.broadcast %lhs to <16xf32>
+//   vector.fma vector<16xf32>
+// ```
+struct VectorContractToFMA : public OpRewritePattern<vector::ContractionOp> {
+  using OpRewritePattern<vector::ContractionOp>::OpRewritePattern;
+
+  LogicalResult matchAndRewrite(vector::ContractionOp contractOp,
+                                PatternRewriter &rewriter) const override {
+
+    if (contractOp.getKind() != vector::CombiningKind::ADD) {
+      return rewriter.notifyMatchFailure(contractOp,
+                                         "Expects add combining kind");
+    }
+
+    VectorType lhsTy = contractOp.getLhsType();
+    if (!lhsTy.getElementType().isF32())
----------------
adam-smnk wrote:

You should also verify that `acc` has correct element type. And add relevant negative tests please.
Might be simplest to check that all operands have the same type.

https://github.com/llvm/llvm-project/pull/168074


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