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

[Kiran Chandramohan]

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@@ -0,0 +1,367 @@
+//===- 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 operand of a `vector.contract`. This function is intended to abstract
+// away from the particular way a value is extended before feeding it into the
+// `vector.contract` - via zero-extend or an explicit or implicit sign-extend
+// (for implicit sign-extension see `vector.contract` documentation).
+//
+// The template parameter `Op` indicates the extension operation (explicir or
+// implicit) for which we are checking.
+//
+// Return success only for extensions from `i8` to `i32`.
+template <typename Op>
+std::optional<Value> getExtOperand(Value v, Type i8Ty, Type i32Ty) {
+
+  static_assert(llvm::is_one_of<Op, arith::ExtSIOp, arith::ExtUIOp>::value,
+                "Must be instantiated with either sign- or zero- extension op");
+
+  // If the operand is not defined by an explicit extend operation of the
+  // accepted operation type allow for an implicit sign-extension.
+  auto extOp = dyn_cast_or_null<Op>(v.getDefiningOp());
+  if (!extOp) {
+    if constexpr (std::is_same<Op, arith::ExtSIOp>::value) {
+      auto vTy = cast<VectorType>(v.getType());
+      if (vTy.getElementType() != i8Ty)
+        return {};
+      return v;
+    }
+    return {};
+  }
+
+  // If the operand is defined by an explicit extend operation of the accepted
+  // operation type, check it's extented from `i8` to `i32`.
+  auto inOp = extOp.getIn();
+  auto inTy = dyn_cast<VectorType>(inOp.getType());
+  if (!inTy || inTy.getElementType() != i8Ty)
+    return {};
+
+  auto outTy = dyn_cast<VectorType>(extOp.getType());
+  if (!outTy || outTy.getElementType() != i32Ty)
+    return {};
+
+  return inOp;
+}
+
+// Designate the operation (resp. instruction) used to do sub-tile matrix
+// multiplications.
+enum class MMLA {
+  Signed,      // smmla
+  Unsigned,    // ummla
+  Mixed,       // usmmla
+  MixedSwapped // usmmla with LHS and RHS swapped
+};
+
+// Create the matrix multply and accumulate operation according to `op`.
+Value createMMLA(PatternRewriter &rewriter, MMLA op, Location loc,
+                 mlir::VectorType accType, Value acc, Value lhs, Value rhs) {
+  switch (op) {
+  case MMLA::Signed:
+    return rewriter.create<arm_sve::SmmlaOp>(loc, accType, acc, lhs, rhs);
+  case MMLA::Unsigned:
+    return rewriter.create<arm_sve::UmmlaOp>(loc, accType, acc, lhs, rhs);
+  case MMLA::Mixed:
+    return rewriter.create<arm_sve::UsmmlaOp>(loc, accType, acc, lhs, rhs);
+  case MMLA::MixedSwapped:
+    // The accumulator comes transposed and the result will be transposed
+    // later, so all we have to do here is swap the operands.
+    return rewriter.create<arm_sve::UsmmlaOp>(loc, accType, acc, rhs, lhs);
----------------
kiranchandramohan wrote:

I see `using namespace mlir::arm_sve;` at the top of this file. Is the `arm_sve::` prefix still required?

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