op_maximum.py

# Copyright 2024-2025 Arm Limited and/or its affiliates.
#
# This source code is licensed under the BSD-style license found in the
# LICENSE file in the root directory of this source tree.

# pyre-unsafe

from typing import List

import executorch.backends.arm.tosa_quant_utils as tqutils
import serializer.tosa_serializer as ts  # type: ignore

from executorch.backends.arm._passes.fold_qdq_with_annotated_qparams_pass import (
    get_input_qparams,
)
from executorch.backends.arm.operators.node_visitor import (
    NodeVisitor,
    register_node_visitor,
)
from executorch.backends.arm.tosa_mapping import TosaArg
from executorch.backends.arm.tosa_utils import tosa_shape

from serializer.tosa_serializer import TosaOp
from torch.fx import Node


@register_node_visitor
class MaxVisitor(NodeVisitor):
    target = "aten.maximum.default"

    def __init__(self, *args):
        super().__init__(*args)

    def define_node(
        self,
        node: Node,
        tosa_graph: ts.TosaSerializer,
        inputs: List[TosaArg],
        output: TosaArg,
    ) -> None:
        assert inputs[0].dtype == inputs[1].dtype

        scale_back = 1.0
        max_output = output
        if inputs[0].dtype == ts.DType.INT8:
            input_qparams = get_input_qparams(node)
            assert (
                len(input_qparams) == 2
            ), f"Both inputs needs to have quantization information for {node}"
            # insert RESCALEs to int32
            assert (
                input_qparams[0] == input_qparams[1]
            ), "Both inputs must have same quantization for MAX"

            operand_inputs, scale_back = tqutils.insert_rescale_ops_to_int32(
                tosa_graph, inputs, node
            )

            output.shape = tosa_shape(output.shape, output.dim_order)
            max_output = tosa_graph.addIntermediate(output.shape, ts.DType.INT32)
        else:
            operand_inputs = inputs

        tosa_graph.addOperator(
            TosaOp.Op().MAXIMUM,
            [
                operand_inputs[0].name,
                operand_inputs[1].name,
            ],
            [max_output.name],
        )

        if output.dtype == ts.DType.INT8:
            # insert RESCALE from int32 back to int8
            tqutils.insert_rescale_op_to_int8(tosa_graph, max_output, scale_back, node)