Changing logic to deal with graphs with derived quantization spec

[RahulC7]

Summary:
We want to add a test for default_addmm_A8W8 to fully finish testing CadenceDefaultQuantizer. However there are a couple changes we need to make to the testing function.

Change 1: We allow passing None in the vec of QuantizationSpec

This is because the addmm op has 3 inputs: bias, mat1, mat2. The bias uses a DerivedQuantizationSpec, which is dynamically constructed with references to the actual graph nodes (mat1 and mat2). We can't construct an identical DerivedQuantizationSpec in the test because we'd need to reference the exact same node objects that the quantizer creates internally. Since we can't compare it directly, we use None to skip validation for that input. If mat1 and mat2 are quantized correctly, the derived bias spec will be correct too.

https://www.internalfb.com/code/fbsource/[2cfdb40fd8b628da2f46366115516408cfb9f50f]/xplat/executorch/backends/cadence/aot/quantizer/patterns.py?lines=91-103

Change 2: We changed how we iterate through input_qspec_map

input_qspec_map is a dictionary mapping input nodes to their qspecs. The iteration order depends on insertion order, which follows how the quantizer processes PartitionAnchors.

Each QuantizationPattern implements a get_anchors() method that returns a PartitionAnchors describing which arguments are inputs, weights, biases and nodes. This is relevant because for addmm, the PartitionAnchors lists them as inputs=[(node, 1)], weights=[(node, 2)], biases=[(node, 0, ...)]. So the map might iterate in order mat1, mat2, bias (args indices 1, 2, 0) rather than bias, mat1, mat2 (args indices 0, 1, 2).

This means that our previous way of iterating wouldn't work. Thus, we now use the following way to iterate:

for input_node, input_qspec in annotation.input_qspec_map.items():
      // Find the index of this input node in the op's args
      arg_index = None
      for i, arg in enumerate(op_node.args):
          if arg is input_node:
              arg_index = i
              break
      self.assertIsNotNone(
          arg_index,
          f"Input node {input_node} not found in op_node.args",
      )
      # Skip comparison if expected qspec is None (e.g., for DerivedQuantizationSpec)
      if expected_input_qspecs[arg_index] is not None:
          self.assertEqual(
              input_qspec,
              expected_input_qspecs[arg_index],
              f"Input qspec mismatch at arg index {arg_index}",
          )

The new code looks up which argument index each input_node corresponds to by searching through op_node.args, rather than assuming the enumeration index i matches the argument position.

Differential Revision: D88955761

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As of commit bafed32 with merge base 6785e1f ():

UNSTABLE - The following job is marked as unstable, possibly due to flakiness on trunk:

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[Copilot]

Pull request overview

This PR adds comprehensive test coverage for several Cadence quantizers, including the CadenceDefaultQuantizer, by enhancing the testing framework to handle graphs with derived quantization specifications. The key innovation is allowing None in expected input quantization specs to skip validation of dynamically-constructed DerivedQuantizationSpec objects, and updating the iteration logic to handle non-sequential argument ordering in PartitionAnchors.

• Added test coverage for 5 previously untested quantizer classes: CadenceDefaultQuantizer, CadenceWakeWordQuantizer, CadenceWith16BitConvActivationsQuantizer, CadenceWithLayerNormQuantizer, and CadenceWithSoftmaxQuantizer
• Enhanced testing framework to support DerivedQuantizationSpec by allowing None values in expected input specs
• Updated iteration logic to map input nodes to argument positions dynamically, handling cases where the quantizer's internal ordering differs from argument position order

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