[Mlir-commits] [mlir] [MLIR][ArmSVE] Add initial lowering of vector.contract to SVE `*MMLA` instructions (PR #135636)

[Andrzej Warzyński]

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@@ -0,0 +1,358 @@
+//===- LowerContractionToSMMLAPattern.cpp - Contract to SMMLA ---*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements lowering patterns from vector.contract to operations
+// that map to instructions from the SVE FEAT_I8MM extension.
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Dialect/Arith/IR/Arith.h"
+#include "mlir/Dialect/ArmSVE/IR/ArmSVEDialect.h"
+#include "mlir/Dialect/ArmSVE/Transforms/Transforms.h"
+#include "mlir/Dialect/Func/IR/FuncOps.h"
+#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
+#include "mlir/Dialect/Utils/IndexingUtils.h"
+#include "mlir/Dialect/Vector/IR/VectorOps.h"
+#include "mlir/IR/AffineMap.h"
+#include "mlir/IR/PatternMatch.h"
+#include "mlir/Transforms/GreedyPatternRewriteDriver.h"
+
+#include "mlir/Dialect/UB/IR/UBOps.h"
+
+#define DEBUG_TYPE "lower-contract-to-arm-sve-i8mm"
+
+using namespace mlir;
+using namespace mlir::arm_sve;
+
+namespace {
+// Get the LHS or RHS side operand of a vector contract. Handle two cases
+//   * if the operand is a sign- or zero- extend operation of type `T` from i8
+//     to i32, return the value before the extension, otherwise
+//   * if the operand is of i8 type and the operation is sign-extend, return the
+//     operand itself.
+//
+// This way we handle both explicit sign- or zero- extension or implicit
+// sign-extension.
----------------
banach-space wrote:

OK, thanks for the reminder! 

Could you add a reference to the `vector.contract` docs? That basically explains "why" sign-extension is assumed. Also, that assumption is bound to evolve in the future and we should make it easy to find places where it informs the actual lowering (this might be the only example). Thanks!

https://github.com/llvm/llvm-project/pull/135636