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| 1 | +# (c) Meta Platforms, Inc. and affiliates. Confidential and proprietary. |
| 2 | + |
| 3 | +# pyre-unsafe |
| 4 | + |
| 5 | + |
| 6 | +# This file contains all the functions that simplify args of an op |
| 7 | + |
| 8 | +import sys |
| 9 | +from typing import Optional |
| 10 | + |
| 11 | +from executorch.backends.cadence.aot.pass_utils import ( |
| 12 | + CadencePassAttribute, |
| 13 | + register_cadence_pass, |
| 14 | +) |
| 15 | + |
| 16 | +from executorch.exir.dialects._ops import ops as exir_ops |
| 17 | +from executorch.exir.pass_base import ExportPass, ProxyValue |
| 18 | + |
| 19 | + |
| 20 | +@register_cadence_pass(CadencePassAttribute(opt_level=0)) |
| 21 | +class SimplifySliceOpPass(ExportPass): |
| 22 | + """ |
| 23 | + Simplify the start and end indices of slice and slice_scatter ops. |
| 24 | + """ |
| 25 | + |
| 26 | + def adjust_slice_range( |
| 27 | + self, |
| 28 | + length: int, |
| 29 | + start: Optional[int] = None, |
| 30 | + end: Optional[int] = None, |
| 31 | + step: int = 1, |
| 32 | + ) -> tuple[int, int]: |
| 33 | + # Get the start index and end index |
| 34 | + start_val = start if start is not None else 0 |
| 35 | + end_val = end if end is not None else sys.maxsize # 2^63 – 1 |
| 36 | + |
| 37 | + # If start_val and end_val are negative, add length to them |
| 38 | + if start_val < 0: |
| 39 | + start_val += length |
| 40 | + if end_val < 0: |
| 41 | + end_val += length |
| 42 | + |
| 43 | + # If the start val is still outside the tensor_size along the sliced |
| 44 | + # dimension, adjust it accordingly. |
| 45 | + if start_val < 0: |
| 46 | + start_val = 0 |
| 47 | + elif start_val >= length: |
| 48 | + start_val = length |
| 49 | + |
| 50 | + # If the end val is still outside the tensor_size along the sliced |
| 51 | + # dimension, adjust it accordingly. |
| 52 | + if end_val < start_val: |
| 53 | + end_val = start_val |
| 54 | + elif end_val >= length: |
| 55 | + end_val = length |
| 56 | + |
| 57 | + # Return the adjusted start and end indices |
| 58 | + return (start_val, end_val) |
| 59 | + |
| 60 | + def call_operator(self, op, args, kwargs, meta): |
| 61 | + # We are only interested in slice_copy or slice_scatter ops |
| 62 | + if op not in { |
| 63 | + exir_ops.edge.aten.slice_copy.Tensor, |
| 64 | + exir_ops.edge.aten.slice_scatter.default, |
| 65 | + }: |
| 66 | + return super().call_operator(op, args, kwargs, meta) |
| 67 | + |
| 68 | + # Check if it is a slice_scatter op or not. The slice_scatter op has |
| 69 | + # an extra src argument at index 1. |
| 70 | + slice_scatter = op == exir_ops.edge.aten.slice_scatter.default |
| 71 | + # Parse the arguments |
| 72 | + # Extract the tensor to be sliced, and the slicing dimension |
| 73 | + in_tensor = args[0].to_tensor() if isinstance(args[0], ProxyValue) else args[0] |
| 74 | + dim = args[1 + slice_scatter] if len(args) > 1 + slice_scatter else 0 |
| 75 | + # Make dim non-negative |
| 76 | + dim = dim if dim >= 0 else dim + in_tensor.dim() |
| 77 | + length = in_tensor.size(dim) |
| 78 | + |
| 79 | + # Get the adjusted start and end indices |
| 80 | + start_val = args[2 + slice_scatter] if len(args) > 2 + slice_scatter else None |
| 81 | + end_val = args[3 + slice_scatter] if len(args) > 3 + slice_scatter else None |
| 82 | + step = args[4 + slice_scatter] if len(args) > 4 + slice_scatter else 1 |
| 83 | + (start_val, end_val) = self.adjust_slice_range(length, start_val, end_val, step) |
| 84 | + |
| 85 | + # If the start_val is geq end_val, then we can return an empty tensor |
| 86 | + # for slice op, or input for slice_scatter op. |
| 87 | + if start_val >= end_val and slice_scatter: |
| 88 | + return args[0] |
| 89 | + if start_val >= end_val: |
| 90 | + empty_shape = [x for x in in_tensor.shape if x != 0] |
| 91 | + empty_shape[dim] = 0 |
| 92 | + return super().call_operator( |
| 93 | + exir_ops.edge.aten.full.default, |
| 94 | + (tuple(empty_shape), 0), |
| 95 | + {"dtype": in_tensor.dtype}, |
| 96 | + meta, |
| 97 | + ) |
| 98 | + |
| 99 | + # Create new args |
| 100 | + new_args = ( |
| 101 | + (args[0],) |
| 102 | + + ((args[1],) if slice_scatter else ()) |
| 103 | + + (dim, start_val, end_val, step) |
| 104 | + ) |
| 105 | + return super().call_operator(op, new_args, kwargs, meta) |
| 106 | + |
| 107 | + |
| 108 | +# This class encapsulates all the functions that simplify the op's args |
| 109 | +class CadenceSimplifyOpsInGraph: |
| 110 | + passes = [ |
| 111 | + SimplifySliceOpPass, |
| 112 | + ] |
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