fix 4326: bound exported dynamic shapes and normalize symbolic slice …

py/torch_tensorrt/dynamo/_compiler.py

@@ -897,7 +897,6 @@ def _insert_complex_io_adapters(
         partitioned_module.graph.lint()
         partitioned_module.recompile()
 
-
 @fn_supports_debugger  # type: ignore[misc]
 def compile_module(
     gm: torch.fx.GraphModule,

py/torch_tensorrt/dynamo/conversion/aten_ops_converters.py

@@ -816,6 +816,7 @@ def aten_ops_rsqrt(
     )
 
 
+@dynamo_tensorrt_converter(operator.neg, supports_dynamic_shapes=True)
 @dynamo_tensorrt_converter(torch.ops.aten.neg.default, supports_dynamic_shapes=True)
 def aten_ops_neg(
     ctx: ConversionContext,
@@ -2223,6 +2224,7 @@ def aten_ops_maximum(
     )
 
 
+@dynamo_tensorrt_converter(torch.sym_min, supports_dynamic_shapes=True)
 @dynamo_tensorrt_converter(torch.ops.aten.minimum.default, supports_dynamic_shapes=True)
 def aten_ops_minimum(
     ctx: ConversionContext,

py/torch_tensorrt/dynamo/lowering/passes/_aten_lowering_pass.py

@@ -12,6 +12,7 @@
 
 from .complex_graph_rewrite import complex_graph_detection
 from .constant_folding import constant_fold
+from .eliminate_sym_min_int64_max import eliminate_sym_min_int64_max
 from .force_causal_efficient_attention import force_causal_efficient_attention
 from .fuse_prims_broadcast import fuse_prims_broadcast
 from .pass_manager import DynamoPassManager
@@ -23,6 +24,7 @@
 from .replace_fused_rms_norm import replace_fused_rms_norm
 from .replace_max_pool_with_indices import replace_max_pool_with_indices
 from .rule_based_autocast import rule_based_autocast
+from .normalize_negative_slice_stop import normalize_negative_slice_stop
 
 pre_lowering_pass_list = [
     remove_detach,
@@ -41,6 +43,8 @@
     remove_num_users_is_0_nodes,
     complex_graph_detection,
     force_causal_efficient_attention,
+    eliminate_sym_min_int64_max,
+    normalize_negative_slice_stop,
 ]
 
 if not is_tegra_platform():

py/torch_tensorrt/dynamo/lowering/passes/eliminate_sym_min_int64_max.py

@@ -0,0 +1,50 @@
+import sys
+
+import torch
+from torch.fx import GraphModule, Node
+
+from .pass_utils import clean_up_graph_after_modifications
+
+
+_INT64_MAX = 2**63 - 1
+_SYM_MIN = getattr(torch, "sym_min", None)
+
+
+def _is_int64_max(x: object) -> bool:
+    return isinstance(x, int) and x in (sys.maxsize, _INT64_MAX)
+
+
+def eliminate_sym_min_int64_max(
+    gm: GraphModule, settings: object = None
+) -> GraphModule:
+    """Remove no-op sym_min nodes where one operand is INT64_MAX.
+
+    torch.export may emit sym_min(sym, INT64_MAX) for an effectively unbounded
+    symbolic value. That expression is equivalent to sym, and leaving it in the
+    graph can produce runtime calls to torch.sym_min with Tensor inputs.
+    """
+    if _SYM_MIN is None:
+        return gm
+
+    modified = False
+    for node in list(gm.graph.nodes):
+        if (
+            node.op != "call_function"
+            or node.target is not _SYM_MIN
+            or len(node.args) < 2
+        ):
+            continue
+
+        lhs, rhs = node.args[:2]
+        if _is_int64_max(rhs) and isinstance(lhs, Node):
+            passthrough = lhs
+        elif _is_int64_max(lhs) and isinstance(rhs, Node):
+            passthrough = rhs
+        else:
+            continue
+
+        node.replace_all_uses_with(passthrough)
+        gm.graph.erase_node(node)
+        modified = True
+
+    return clean_up_graph_after_modifications(gm) if modified else gm

py/torch_tensorrt/dynamo/lowering/passes/normalize_negative_slice_stop.py

@@ -0,0 +1,85 @@
+import operator
+from typing import Optional
+
+import torch
+from torch.fx import GraphModule, Node
+from torch_tensorrt.dynamo.lowering._SubgraphBuilder import SubgraphBuilder
+
+from .pass_utils import clean_up_graph_after_modifications
+
+
+def _negative_symint_operand(x: object) -> Optional[object]:
+    # Return n for symbolic bounds represented as -n. The caller rewrites
+    # that bound to dim_size - n, matching Python's negative indexing rules.
+    if (
+        isinstance(x, Node)
+        and x.op == "call_function"
+        and x.target in (operator.neg, torch.ops.aten.neg.default)
+        and len(x.args) == 1
+    ):
+        return x.args[0]
+    return None
+
+
+def _rank(x: Node) -> Optional[int]:
+    val = x.meta.get("val")
+    if isinstance(val, torch.Tensor):
+        return val.dim()
+    if hasattr(val, "shape"):
+        return len(val.shape)
+    return None
+
+
+def normalize_negative_slice_stop(
+    gm: GraphModule, settings: object = None
+) -> GraphModule:
+    """Normalize negative symbolic slice bounds to positive dim-relative bounds.
+
+    Python slicing accepts negative bounds such as x[-n:] or x[:-n]. TensorRT
+    shape expressions need the equivalent positive bound, dim_size - n.
+    """
+    modified = False
+
+    for node in list(gm.graph.nodes):
+        if node.op != "call_function" or node.target != torch.ops.aten.slice.Tensor:
+            continue
+
+        args = list(node.args)
+        if len(args) < 3:
+            continue
+
+        input_node, dim = args[:2]
+        if not isinstance(input_node, Node) or not isinstance(dim, int):
+            continue
+
+        rank = _rank(input_node)
+        if rank is not None:
+            # Match PyTorch dim normalization for negative dims.
+            dim = dim % rank
+
+        rewritten = False
+        # aten.slice.Tensor can appear as (input, dim, start) or
+        # (input, dim, start, stop, ...). Normalize either symbolic bound.
+        for bound_index in (2, 3):
+            if len(args) <= bound_index:
+                continue
+
+            bound = args[bound_index]
+            positive_offset = _negative_symint_operand(bound)
+            if positive_offset is None:
+                continue
+
+            with SubgraphBuilder(gm.graph, node.prev) as b:
+                dim_size = b(torch.ops.aten.sym_size.int, input_node, dim)
+                # A negative symbolic bound -n becomes dim_size - n.
+                normalized_bound = b(operator.sub, dim_size, positive_offset)
+
+            args[bound_index] = normalized_bound
+            rewritten = True
+
+        if rewritten:
+            args[1] = dim
+            node.args = tuple(args)
+            modified = True
+
+    return clean_up_graph_after_modifications(gm) if modified else gm

tests/py/dynamo/lowering/test_aten_lowering_passes.py

@@ -1,3 +1,6 @@
+import operator
+import sys
+
 import torch
 import torch_tensorrt
 from torch.testing._internal.common_utils import TestCase, run_tests
@@ -278,6 +281,102 @@ def forward(self, x: torch.Tensor):
         self.assertTrue(True)
 
 
+class TestNormalizeNegativeSliceStop(TestCase):
+    def test_normalizes_negative_symbolic_start_bound(self):
+        from torch_tensorrt.dynamo.lowering.passes.normalize_negative_slice_stop import (
+            normalize_negative_slice_stop,
+        )
+
+        graph = torch.fx.Graph()
+        x = graph.placeholder("x")
+        x.meta["val"] = torch.empty(2, 5, 3)
+        n = graph.placeholder("n")
+        neg = graph.call_function(operator.neg, args=(n,))
+        sliced = graph.call_function(torch.ops.aten.slice.Tensor, args=(x, -2, neg))
+        graph.output(sliced)
+
+        gm = torch.fx.GraphModule({}, graph)
+        gm = normalize_negative_slice_stop(gm)
+
+        slice_node = next(
+            node
+            for node in gm.graph.nodes
+            if node.op == "call_function" and node.target == torch.ops.aten.slice.Tensor
+        )
+        self.assertEqual(slice_node.args[1], 1)
+
+        normalized_start = slice_node.args[2]
+        self.assertEqual(normalized_start.op, "call_function")
+        self.assertEqual(normalized_start.target, operator.sub)
+
+        dim_size, offset = normalized_start.args
+        self.assertEqual(dim_size.target, torch.ops.aten.sym_size.int)
+        self.assertEqual(dim_size.args[0], x)
+        self.assertEqual(dim_size.args[1], 1)
+        self.assertEqual(offset, n)
+
+    def test_normalizes_negative_symbolic_stop_bound(self):
+        from torch_tensorrt.dynamo.lowering.passes.normalize_negative_slice_stop import (
+            normalize_negative_slice_stop,
+        )
+
+        graph = torch.fx.Graph()
+        x = graph.placeholder("x")
+        x.meta["val"] = torch.empty(2, 5, 3)
+        n = graph.placeholder("n")
+        neg = graph.call_function(torch.ops.aten.neg.default, args=(n,))
+        sliced = graph.call_function(torch.ops.aten.slice.Tensor, args=(x, 1, 0, neg))
+        graph.output(sliced)
+
+        gm = torch.fx.GraphModule({}, graph)
+        gm = normalize_negative_slice_stop(gm)
+
+        slice_node = next(
+            node
+            for node in gm.graph.nodes
+            if node.op == "call_function" and node.target == torch.ops.aten.slice.Tensor
+        )
+
+        normalized_stop = slice_node.args[3]
+        self.assertEqual(normalized_stop.op, "call_function")
+        self.assertEqual(normalized_stop.target, operator.sub)
+
+        dim_size, offset = normalized_stop.args
+        self.assertEqual(dim_size.target, torch.ops.aten.sym_size.int)
+        self.assertEqual(dim_size.args[0], x)
+        self.assertEqual(dim_size.args[1], 1)
+        self.assertEqual(offset, n)
+
+
+class TestEliminateSymMinInt64Max(TestCase):
+    def test_eliminates_noop_sym_min_int64_max(self):
+        if not hasattr(torch, "sym_min"):
+            self.skipTest("torch.sym_min is not available")
+
+        from torch_tensorrt.dynamo.lowering.passes.eliminate_sym_min_int64_max import (
+            eliminate_sym_min_int64_max,
+        )
+
+        graph = torch.fx.Graph()
+        x = graph.placeholder("x")
+        rhs_int64_max = graph.call_function(torch.sym_min, args=(x, sys.maxsize))
+        lhs_int64_max = graph.call_function(torch.sym_min, args=(2**63 - 1, x))
+        graph.output((rhs_int64_max, lhs_int64_max))
+
+        gm = torch.fx.GraphModule({}, graph)
+        gm = eliminate_sym_min_int64_max(gm)
+
+        self.assertFalse(
+            any(
+                node.op == "call_function" and node.target is torch.sym_min
+                for node in gm.graph.nodes
+            )
+        )
+
+        output_node = next(node for node in gm.graph.nodes if node.op == "output")
+        self.assertEqual(output_node.args[0], (x, x))
+
+
 class TestRewriteEfficientAttention(TestCase):
     def test_force_causal_efficient_attention(self):
         class RewriteEfficientAttention(torch.nn.Module):