…76452)

is_from_source(source, target) previously only compared at the root of
the ChainedSource hierarchy. This meant that
is_from_source(AttrSource(X, 'c'), X) returned False when X was itself
a ChainedSource (e.g. UnspecializedNNModuleSource(GlobalSource(...))),
because the function walked past X all the way to the root before
comparing.

Check source == target at each level before recursing so that
intermediate sources are correctly recognized as ancestors.

Authored with Claude.

Pull Request resolved: #176452
Approved by: https://github.com/williamwen42
ghstack dependencies: #176515

…ame (pytorch#176515)"

This reverts commit c4ec0b8.

…ame (#176515)" (#176948)

## Summary
Reverts #176515.

This is a prerequisite for reverting the full `[fx] Move _Namespace to C++` series (#170962), which was reverted internally due to S627920 but the revert was never exported to GitHub.

The quadratic fix patches `torch/csrc/fx/graph.cpp` which was introduced by #170962. This revert must land first so that #170962 can be cleanly reverted afterwards.

## Test plan
CI — this revert removes a bugfix from C++ code that will itself be reverted in a follow-up PR.
Pull Request resolved: #176948
Approved by: https://github.com/izaitsevfb, https://github.com/huydhn

## Summary

Reverts #170946

This reverts commit fa27d4f.

The two stacked PRs (#170962 and #170973) have already been reverted on main:
- `0a06050b` Revert "[fx] Move _FindNodesLookupTable and _node_list to C++ (#170973)"
- `2ee3377b` Revert "[fx] Move _Namespace to C++ (#170962)"
- `fb60dd58` Revert "[fx] Fix quadratic name generation in _NamespaceBase.create_name (#176515)"

The only merge conflict was in `torch/fx/node.py` due to a type annotation modernization PR (#176308, `Optional[X]` → `X | None`). The conflict was resolved by keeping the modern annotation style while restoring the original Python implementation.

## Test plan
CI

Pull Request resolved: #177047
Approved by: https://github.com/huydhn

reland of #176515 but earlier the file already moved to C++, so sending a python only change.

[ghstack-poisoned]

reland of #176515 but earlier the file already moved to C++, so sending a python only change.

ghstack-source-id: e0bdb29
Pull Request resolved: #177217

reland of #176515 but earlier the file already moved to C++, so sending a python only change.
Pull Request resolved: #177217
Approved by: https://github.com/jansel, https://github.com/zou3519

create_name stores its counter under base_count[base] (e.g. "sin") but
was looking it up under base_count[candidate] (e.g. "sin_1").  When the
candidate already has a numeric suffix the lookup always misses, so the
while-loop that probes for a free name starts from the regex-extracted
number instead of the stored counter — degrading to O(existing_names)
per call.

This makes repeated node_copy of the same subgraph (as done by
inline_invoke_subgraph) quadratic: for an 80-layer model the pass went
from ~100ms to ~4.6s.

Fix: look up base_count[base] to match the store.

Authored with Claude.

ghstack-source-id: 9951e62
Pull Request resolved: pytorch/pytorch#176515