Arm backend: Support SymInts in size_adjust_input (#18226)

Make sure SizeAdjustInputPass can handle inputs with symbolic shapes.
Also adds tests for SizeAdjustInputPass.

cc @digantdesai @freddan80 @per @zingo @mansnils @Sebastian-Larsson
@robell

Signed-off-by: Oscar Andersson <oscar.andersson@arm.com>

Author: oscarandersson8218

backends/arm/_passes/size_adjust_input_pass.py

@@ -2,8 +2,6 @@
 #
 # This source code is licensed under the BSD-style license found in the
 # LICENSE file in the root directory of this source tree.
-
-
 from typing import cast, Sequence, Set, Type, TypeAlias
 
 import torch.fx
@@ -13,10 +11,12 @@
     expand_around_channel,
 )
 from executorch.backends.arm._passes.rewrite_conv_pass import RewriteConvPass
+from executorch.backends.arm.tosa.specification import get_context_shape_env
 from executorch.exir.dialects._ops import ops as exir_ops
 from executorch.exir.pass_base import ExportPass, PassResult
 
 Slices: TypeAlias = list[tuple[int, int, int]]
+SymIntLike = int | torch.SymInt
 
 conv2d_op = exir_ops.edge.aten.convolution.default
 max_pooling_op = exir_ops.edge.aten.max_pool2d.default
@@ -26,20 +26,34 @@
 valid_operators = [conv2d_op, max_pooling_op, avg_pooling_op]
 
 
-def conv_remainder(input_length, pad, dilation, weight, stride) -> int:
+def conv_remainder(
+    input_length: SymIntLike, pad: int, dilation: int, weight: int, stride: int
+) -> SymIntLike:
     """Returns the remainder of input_length; given the padding, dilation,
     stride, and kernel size.
     """
     return (input_length + 2 * pad - dilation * (weight - 1) - 1) % stride
 
 
-def pooling_remainder(input_size, pad, kernel_size, stride) -> int:
+def pooling_remainder(
+    input_size: SymIntLike, pad: int, kernel_size: int, stride: int
+) -> SymIntLike:
     """Returns the remainder of input_length; given the padding, stride, and
     kernel size.
     """
     return (input_size + 2 * pad - kernel_size) % stride
 
 
+def _greater_than(input: SymIntLike, other: int) -> bool | torch.SymBool:
+    """Returns whether an int or SymInt is greater than another value."""
+    if isinstance(input, torch.SymInt):
+        shape_env = get_context_shape_env()
+        value_ranges = shape_env.bound_sympy(input.node.expr)
+        return value_ranges.upper > other
+    else:
+        return input > other
+
+
 def get_slices_convolution(conv_node: torch.fx.Node) -> Slices:
     slices = []
 
@@ -59,7 +73,7 @@ def get_slices_convolution(conv_node: torch.fx.Node) -> Slices:
         remainder = conv_remainder(
             input_shape[dim], pad, dilation, weight_shape[dim], stride
         )
-        if remainder > pad:
+        if _greater_than(remainder, pad):
             adjustment = remainder - pad
             args = (dim, 0, input_shape[dim] - adjustment)
             slices.append(args)
@@ -87,7 +101,7 @@ def get_slices_pooling(pooling_node: torch.fx.Node) -> Slices:
         remainder = pooling_remainder(
             input_shape[dim], pad_size, kernel_length, stride_length
         )
-        if remainder > pad_size:
+        if _greater_than(remainder, pad_size):
             adjustment = remainder - pad_size
             args = (dim, 0, input_shape[dim] - adjustment)
             slices.append(args)