chore: dynamic shape support for flip ops (#3046)

py/torch_tensorrt/dynamo/conversion/aten_ops_converters.py

@@ -3571,7 +3571,7 @@ def aten_ops_pdist(
     )
 
 
-@dynamo_tensorrt_converter(torch.ops.aten.flip.default)
+@dynamo_tensorrt_converter(torch.ops.aten.flip.default, supports_dynamic_shapes=True)
 @enforce_tensor_types(
     {
         0: (TRTTensor,),

py/torch_tensorrt/dynamo/conversion/impl/slice/ops.py

@@ -446,24 +446,51 @@ def flip(
     output_shape = list(input.shape)
     stride_slice = []
 
+    dynamic_shape = has_dynamic_shape(input.shape)
+
     shape = input.shape
     rank = len(shape)
     dims = get_positive_dim(dims, rank)
 
     for i in range(rank):
         if i in dims:
-            start_slice.append(shape[i] - 1)
+            if shape[i] == DYNAMIC_DIM:
+                dim = get_shape(
+                    ctx, target, source_ir, f"{name}_shape_dim_{i}", input, i
+                )
+                last_element_index = impl.elementwise.sub(
+                    ctx, target, source_ir, f"{name}_sub_{i}", dim, 1
+                )
+                start_slice.append(last_element_index)
+            else:
+                start_slice.append(shape[i] - 1)
             stride_slice.append(-1)
         else:
             start_slice.append(0)
             stride_slice.append(1)
 
     layer = ctx.net.add_slice(
         input,
-        start=start_slice,
-        shape=output_shape,
+        start=[] if dynamic_shape else start_slice,
+        shape=[] if dynamic_shape else output_shape,
         stride=stride_slice,
     )
+    if dynamic_shape:
+        output_shape = get_shape_with_dynamic_shape(
+            ctx, target, source_ir, f"{name}_shape", output_shape, input
+        )
+
+        start_slice_tensor = cat(
+            ctx,
+            target,
+            source_ir,
+            f"{name}_start_slice_concat",
+            start_slice,
+            0,
+        )
+        layer.set_input(1, start_slice_tensor)
+        layer.set_input(2, output_shape)
+
     set_layer_name(layer, target, name, source_ir)
     return layer.get_output(0)
 

tests/py/dynamo/conversion/test_flip_aten.py

@@ -2,6 +2,7 @@
 import torch.nn as nn
 from parameterized import parameterized
 from torch.testing._internal.common_utils import run_tests
+from torch_tensorrt import Input
 
 from .harness import DispatchTestCase
 
@@ -33,5 +34,57 @@ def forward(self, x):
         self.run_test(Flip(), inputs)
 
 
+class TestFlipConverterDynamic(DispatchTestCase):
+    @parameterized.expand(
+        [
+            (
+                "3d_dynamic",
+                (2, 1, 1),
+                (2, 2, 1),
+                (3, 2, 4),
+                [2, 1, 0],
+            ),
+            (
+                "3d_dynamic_negative_dim",
+                (2, 1, 1),
+                (2, 2, 1),
+                (3, 2, 4),
+                [-1, 1],
+            ),
+            (
+                "4d_dynamic_static_dim",
+                (3, 1, 1, 1),
+                (3, 2, 1, 2),
+                (3, 2, 4, 5),
+                [0, 2, 3],
+            ),
+            (
+                "3d_dynamic_no_dim",
+                (2, 1, 1),
+                (2, 2, 1),
+                (3, 2, 4),
+                [],
+            ),
+        ]
+    )
+    def test_flip_dynamic(self, _, min_shape, opt_shape, max_shape, dims):
+        class Flip(nn.Module):
+            def forward(self, x):
+                return torch.ops.aten.flip.default(x, dims)
+
+        input_specs = [
+            Input(
+                min_shape=min_shape,
+                opt_shape=opt_shape,
+                max_shape=max_shape,
+                dtype=torch.float,
+            ),
+        ]
+        self.run_test_with_dynamic_shape(
+            Flip(),
+            input_specs,
+        )
+
+
 if __name__ == "__main__":
     run_tests()