enable unbacked with aot_compile (#30462)

Signed-off-by: Laith Sakka <lsakka@meta.com>

tests/compile/test_dynamic_shapes_compilation.py

@@ -36,7 +36,7 @@ def get_test_models():
         DynamicShapesType.BACKED_SIZE_OBLIVIOUS,
     ],
 )
-@pytest.mark.parametrize("use_aot_compile", ["0"])
+@pytest.mark.parametrize("use_aot_compile", ["0", "1"])
 @pytest.mark.parametrize("use_bytecode_hook", [True, False])
 @pytest.mark.parametrize("evaluate_guards", [False, True])
 @pytest.mark.skipif(
@@ -54,6 +54,12 @@ def test_dynamic_shapes_compilation(
     if use_bytecode_hook and shapes_type == DynamicShapesType.UNBACKED:
         pytest.skip("UNBACKED dynamic shapes require VLLM_USE_BYTECODE_HOOK=0")
 
+    if evaluate_guards and shapes_type == DynamicShapesType.UNBACKED:
+        pytest.skip("unbacked dynamic shapes do not add guards")
+
+    if evaluate_guards and use_aot_compile:
+        pytest.skip("evaluate_guards requires use_aot_compile=0")
+
     monkeypatch.setenv("VLLM_USE_AOT_COMPILE", use_aot_compile)
     monkeypatch.setenv("VLLM_USE_BYTECODE_HOOK", "1" if use_bytecode_hook else "0")
 
@@ -120,7 +126,7 @@ def test_model_specialization_with_evaluate_guards(
         and dynamic_shapes_type == DynamicShapesType.BACKED
         and evaluate_guards
     ):
-        pytest.skip("evaluate_guards for backed does not work with aot_compile =1")
+        pytest.skip("evaluate_guards for backed does not work with aot_compile=1")
 
     @support_torch_compile
     class ModelWithSizeCheck(torch.nn.Module):

vllm/compilation/decorators.py

@@ -390,14 +390,6 @@ def _support_torch_compile(
             serialized backend artifacts), then we need to generate a new AOT
             compile artifact from scratch.
             """
-            # Validate that AOT compile is not used with unbacked dynamic
-            # shapes. aot_compile re-allocates backed symbols post dynamo!
-            if ds_type == DynamicShapesType.UNBACKED:
-                raise ValueError(
-                    "AOT compilation is not compatible with UNBACKED dynamic shapes. "
-                    "Please use BACKED or BACKED_SIZE_OBLIVIOUS dynamic shapes type "
-                    "when VLLM_USE_AOT_COMPILE is enabled."
-                )
             from .caching import compilation_config_hash_factors
 
             factors: list[str] = compilation_config_hash_factors(self.vllm_config)