✨[Feature] Remove requirement for require_full_compilation=False when using input_signature

[gs-olive]

Feature Context

Models which are fully supported in TRT, except for their input type being a collection should be able to be fully-compiled in Torch-TRT. Considering that Torch-executed list packing and list unpacking code is already being inserted (by necessity) even when models are fully supported, there should not be a need to disable full compilation when providing complex input types. Additionally, operators including prim::ListUnpack should not be added to torch_executed_ops automatically upon using input_signature, as they are currently, since evaluators for them exist.

Desired Solution

The preferred solution is to remove the requirement for require_full_compilation=False when using input_signature and to remove the requirement that collection-based operators be executed in fallback:

TensorRT/py/torch_tensorrt/ts/_compile_spec.py

Lines 259 to 300 in 835abf0

	elif compile_spec["input_signature"] is not None:
	log(
	Level.Warning,
	"Input signature parsing is an experimental feature, behavior and APIs may change",
	)
	signature = _parse_input_signature(compile_spec["input_signature"])
	info.input_signature = _C.InputSignature(signature) # py_object
	if not compile_spec["torch_fallback"]["enabled"]:
	raise ValueError(
	"Grouped inputs currently requires partial compilation to be enabled, this restriction will be relaxed in a future release"
	)
	log(
	Level.Debug,
	"Grouped inputs currently requires additional settings to enable the feature",
	)
	log(
	Level.Debug,
	"""Adding the following ops to torch_executed_ops:
	- aten::__getitem__
	- prim::ListConstruct
	- prim::ListUnpack
	- prim::TupleIndex
	- prim::TupleConstruct
	- prim::TupleUnpack
	""",
	)
	compile_spec["torch_fallback"]["forced_fallback_ops"].append(
	"aten::__getitem__"
	)
	compile_spec["torch_fallback"]["forced_fallback_ops"].append(
	"prim::ListConstruct"
	)
	compile_spec["torch_fallback"]["forced_fallback_ops"].append("prim::ListUnpack")
	compile_spec["torch_fallback"]["forced_fallback_ops"].append("prim::TupleIndex")
	compile_spec["torch_fallback"]["forced_fallback_ops"].append(
	"prim::TupleConstruct"
	)
	compile_spec["torch_fallback"]["forced_fallback_ops"].append(
	"prim::TupleUnpack"
	)

This would require modification of the C++ core code as well, to ensure that relaxing this requirement will not cause further issues with the existing compilation phases.

Additional Context

A proof-of-concept for this feature already exists in PR #1599, which could be used as a template to enable full-compilation functionality for collection inputs as well. This would complete the plan for Collection IO as discussed in #629 (comment).

[Christina-Young-NVIDIA]

Pending PR #1599 .