[Quant][PT2E] Enable X86InductorQuantizer single quantizable op(maxpo…

…ol2d) (#105639)

**Summary**
In this PR, we mainly enable 2 things.

- Enable the skeleton of quantization recipe for single quantizable operators in `X86InductorQuantizer`.
- Add quantization recipe of `maxpool2d` and annotate it as input./output share observer.

**Test Plan**
```
python -m pytest test_x86inductor_quantizer.py -k test_maxpool2d_recipe
```

Pull Request resolved: #105639
Approved by: https://github.com/jgong5, https://github.com/jerryzh168
ghstack dependencies: #104580, #104581, #104588, #104590, #105455, #105456

test/quantization/pt2e/test_x86inductor_quantizer.py

@@ -20,7 +20,8 @@
 from enum import Enum
 import itertools
 import torch.ao.quantization.quantizer.x86_inductor_quantizer as xiq
-
+import operator
+from torch.ao.quantization import ObserverBase
 
 class Conv2DType(Enum):
     left = 1
@@ -127,6 +128,18 @@ def forward(self, x):
                 else:
                     return self.relu2(self.conv(x) + self.conv2(x))
 
+    class Conv2dMaxpoolPowModule(nn.Module):
+        def __init__(self):
+            super().__init__()
+            self.conv = nn.Conv2d(2, 2, 1)
+            self.pool = nn.MaxPool2d(1, 1)
+
+        def forward(self, x):
+            x = self.conv(x)
+            x = self.pool(x)
+            return torch.pow(x, 2)
+
+
     class SerialsConv2dAddReLUModule(torch.nn.Module):
         """ Serials of 2 Conv2d -> Add -> ReLU Pattern.
         """
@@ -171,10 +184,13 @@ def _test_quantizer(
             *copy.deepcopy(example_inputs),
             aten_graph=True,
         )
+        export_model = copy.deepcopy(m)
         m = prepare_pt2e(m, quantizer)
         # Calibrate
         m(*example_inputs)
+        prepare_model = copy.deepcopy(m)
         m = convert_pt2e(m)
+        convert_model = copy.deepcopy(m)
         pt2_quant_output = m(*example_inputs)
         node_occurrence = {
             ns.call_function(k): v for k, v in expected_node_occurrence.items()
@@ -185,6 +201,7 @@ def _test_quantizer(
         self.checkGraphModuleNodes(
             m, expected_node_occurrence=node_occurrence, expected_node_list=node_list
         )
+        return export_model, prepare_model, convert_model
 
 @skipIfNoDynamoSupport
 class TestQuantizePT2EX86Inductor(X86InductorQuantTestCase):
@@ -400,3 +417,65 @@ def test_conv2d_serials_binary_unary_with_quantizer_api(self):
                 node_occurrence,
                 node_list,
             )
+
+    @skipIfNoX86
+    def test_maxpool2d_recipe(self):
+        r"""
+        Test pattern: int8_in_int8_out_ops(maxpool) - non_quantizable op(pow)
+        Since maxpool is a int8_in_int8_out_op, there is obs between maxpool and pow.
+        """
+        m = TestHelperModules.Conv2dMaxpoolPowModule().eval()
+        x = torch.rand(1, 2, 14, 14)
+        quantizer = X86InductorQuantizer().set_global(
+            xiq.get_default_x86_inductor_quantization_config()
+        )
+        example_inputs = (x,)
+        node_occurrence = {
+            # one for input and weight of the conv, two for input/output for the maxpool2d
+            torch.ops.quantized_decomposed.quantize_per_tensor.default: 3,
+            torch.ops.quantized_decomposed.dequantize_per_tensor.default: 3,
+            torch.ops.quantized_decomposed.quantize_per_channel.default: 1,
+            torch.ops.quantized_decomposed.dequantize_per_channel.default: 1,
+        }
+        node_list = [
+            torch.ops.quantized_decomposed.quantize_per_tensor.default,
+            torch.ops.quantized_decomposed.dequantize_per_tensor.default,
+            torch.ops.aten.convolution.default,
+            torch.ops.quantized_decomposed.quantize_per_tensor.default,
+            torch.ops.quantized_decomposed.dequantize_per_tensor.default,
+            torch.ops.aten.max_pool2d_with_indices.default,
+            torch.ops.quantized_decomposed.quantize_per_tensor.default,
+            torch.ops.quantized_decomposed.dequantize_per_tensor.default,
+        ]
+        _, prepare_model, _ = self._test_quantizer(
+            m,
+            example_inputs,
+            quantizer,
+            node_occurrence,
+            node_list,
+        )
+        # Check Maxpool2d has share observer at input and output
+        for node in prepare_model.graph.nodes:
+            if (
+                node.op == "call_function"
+                and node.target is torch.ops.aten.max_pool2d_with_indices.default
+            ):
+                maxpool_node = node
+                input_obs_of_maxpool = getattr(
+                    prepare_model, maxpool_node.args[0].target
+                )
+            elif node.op == "call_function" and node.target is operator.getitem:
+                output_obs_of_maxpool = getattr(
+                    prepare_model, list(node.users)[0].target
+                )
+            elif (
+                node.op == "call_function"
+                and node.target is torch.ops.aten.convolution.default
+            ):
+                conv_node = node
+                input_obs_of_conv = getattr(prepare_model, conv_node.args[0].target)
+        self.assertTrue(isinstance(input_obs_of_maxpool, ObserverBase))
+        self.assertTrue(isinstance(output_obs_of_maxpool, ObserverBase))
+        self.assertTrue(isinstance(input_obs_of_conv, ObserverBase))
+        self.assertTrue(input_obs_of_maxpool is output_obs_of_maxpool)
+        self.assertTrue(input_obs_of_maxpool is not input_obs_of_conv)