Reject data-dependent output shapes in infer_output_spec#1722
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When a helion kernel's output contains an unbacked SymInt (indicating a data-dependent shape), raise DataDependentOutputShapeNotSupported in _remap_or_resolve instead of silently concretizing via size_hint. This is a defensive check: currently, type propagation catches known data-dependent ops (nonzero, boolean indexing) before infer_output_spec runs, making this path unreachable in practice. It is left untested for this reason, but serves as a safety net for future ops that may produce unbacked SymInts without a corresponding type propagation check. Also adds test coverage for infer_output_spec symbol remapping with single and multi-output kernels. Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com> Signed-off-by: Yanan Cao <gmagogsfm@gmail.com>
yf225
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The previous code from PR #1722 treated ALL unbacked symbols as data-dependent, but compound expressions like `flag * 2` (= 2*u0) have unbacked symbols that come from known kernel parameters. Fix: check whether unbacked symbols are a subset of sym_remap keys. If yes, substitute concrete values and evaluate. If any symbol is unknown, raise DataDependentOutputShapeNotSupported. Un-skip 3 tests that were broken by the overly broad check: test_kernel_returns_none_in_tuple, test_kernel_returns_none_first_in_tuple, test_kernel_returns_tuple_of_scalars.
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The previous code from PR #1722 treated ALL unbacked symbols as data-dependent, but compound expressions like `flag * 2` (= 2*u0) have unbacked symbols that come from known kernel parameters. Fix: check whether unbacked symbols are a subset of sym_remap keys. If yes, substitute concrete values and evaluate. If any symbol is unknown, raise DataDependentOutputShapeNotSupported. Un-skip 3 tests that were broken by the overly broad check: test_kernel_returns_none_in_tuple, test_kernel_returns_none_first_in_tuple, test_kernel_returns_tuple_of_scalars.
yf225
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The previous code from PR #1722 treated ALL unbacked symbols as data-dependent, but compound expressions like `flag * 2` (= 2*u0) have unbacked symbols that come from known kernel parameters. Fix: check whether unbacked symbols are a subset of sym_remap keys. If yes, substitute concrete values and evaluate. If any symbol is unknown, raise DataDependentOutputShapeNotSupported. Un-skip 3 tests that were broken by the overly broad check: test_kernel_returns_none_in_tuple, test_kernel_returns_none_first_in_tuple, test_kernel_returns_tuple_of_scalars.
yf225
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Mar 20, 2026
The previous code from PR #1722 treated ALL unbacked symbols as data-dependent, but compound expressions like `flag * 2` (= 2*u0) have unbacked symbols that come from known kernel parameters. Fix: check whether unbacked symbols are a subset of sym_remap keys. If yes, substitute concrete values and evaluate. If any symbol is unknown, raise DataDependentOutputShapeNotSupported. Un-skip 3 tests that were broken by the overly broad check: test_kernel_returns_none_in_tuple, test_kernel_returns_none_first_in_tuple, test_kernel_returns_tuple_of_scalars.
hinriksnaer
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Signed-off-by: Yanan Cao <gmagogsfm@gmail.com> Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
yf225
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Mar 23, 2026
The previous code from PR #1722 treated ALL unbacked symbols as data-dependent, but compound expressions like `flag * 2` (= 2*u0) have unbacked symbols that come from known kernel parameters. Fix: check whether unbacked symbols are a subset of sym_remap keys. If yes, substitute concrete values and evaluate. If any symbol is unknown, raise DataDependentOutputShapeNotSupported. Un-skip 3 tests that were broken by the overly broad check: test_kernel_returns_none_in_tuple, test_kernel_returns_none_first_in_tuple, test_kernel_returns_tuple_of_scalars.
yf225
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Mar 23, 2026
The previous code from PR #1722 treated ALL unbacked symbols as data-dependent, but compound expressions like `flag * 2` (= 2*u0) have unbacked symbols that come from known kernel parameters. Fix: check whether unbacked symbols are a subset of sym_remap keys. If yes, substitute concrete values and evaluate. If any symbol is unknown, raise DataDependentOutputShapeNotSupported. Un-skip 3 tests that were broken by the overly broad check: test_kernel_returns_none_in_tuple, test_kernel_returns_none_first_in_tuple, test_kernel_returns_tuple_of_scalars.
umechand-amd
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Mar 23, 2026
Signed-off-by: Yanan Cao <gmagogsfm@gmail.com> Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
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When a helion kernel's output contains an unbacked SymInt (indicating a data-dependent shape) that is produced inside Helion Kernel (via
.item()calls), raiseDataDependentOutputShapeNotSupported.This is a defensive check: currently, type propagation catches known data-dependent ops (nonzero, boolean indexing) before infer_output_spec runs, making this path unreachable in practice. It is left untested for this reason, but serves as a safety net for future ops that may produce unbacked SymInts without a corresponding type propagation check.