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| 1 | +# Copyright (c) Qualcomm Innovation Center, Inc. |
| 2 | +# All rights reserved |
| 3 | +# |
| 4 | +# This source code is licensed under the BSD-style license found in the |
| 5 | +# LICENSE file in the root directory of this source tree. |
| 6 | + |
| 7 | +import torch |
| 8 | +from executorch.exir.pass_base import ExportPass, PassResult |
| 9 | +from torch.fx.experimental.proxy_tensor import make_fx |
| 10 | + |
| 11 | + |
| 12 | +class DecomposeEinsum(ExportPass): |
| 13 | + """ |
| 14 | + Decompose einsum for quantization annotation to work properly. |
| 15 | + """ |
| 16 | + |
| 17 | + def __init__(self) -> None: |
| 18 | + super().__init__() |
| 19 | + |
| 20 | + def call(self, graph_module: torch.fx.GraphModule) -> PassResult: |
| 21 | + graph = graph_module.graph |
| 22 | + for node in graph.nodes: |
| 23 | + if node.target == torch.ops.aten.einsum.default: |
| 24 | + decomposed_module = make_fx( |
| 25 | + node.target, |
| 26 | + tracing_mode="fake", |
| 27 | + )(node.args[0], [arg.meta["val"] for arg in node.args[1]]) |
| 28 | + |
| 29 | + with graph.inserting_before(node): |
| 30 | + # remap is used to map original node values to new node values, |
| 31 | + # which ensures that reference to nodes are correclty updated in the new graph |
| 32 | + remap = {} |
| 33 | + # Different from other nodes, einsum args[0] is the einsum equation, |
| 34 | + # while input nodes are stored in args[1] |
| 35 | + for i, arg in enumerate(node.args[1]): |
| 36 | + remap[f"arg1_{i+1}"] = arg |
| 37 | + |
| 38 | + for decomposed_node in decomposed_module.graph.nodes: |
| 39 | + # This is the arg[0] equation string, which is not required anymore after decomposition |
| 40 | + if "arg0" in decomposed_node.name: |
| 41 | + continue |
| 42 | + |
| 43 | + # no need to copy existent 'output' |
| 44 | + if decomposed_node.op == "output": |
| 45 | + for user in node.users.copy(): |
| 46 | + # remap |
| 47 | + user.replace_input_with( |
| 48 | + node, |
| 49 | + remap[decomposed_node.args[0][0]], |
| 50 | + ) |
| 51 | + # no need to copy existent placeholders |
| 52 | + elif decomposed_node.op == "placeholder": |
| 53 | + # replace node map from string to graph node |
| 54 | + remap[decomposed_node] = remap.pop(decomposed_node.name) |
| 55 | + else: |
| 56 | + remap[decomposed_node] = graph.node_copy( |
| 57 | + decomposed_node, |
| 58 | + arg_transform=lambda x, remap=remap: remap[x], |
| 59 | + ) |
| 60 | + |
| 61 | + graph.erase_node(node) |
| 62 | + |
| 63 | + graph.eliminate_dead_code() |
| 64 | + graph_module.recompile() |
| 65 | + return PassResult(graph_module, True) |
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