[converter] Add aten.masked_scatter lowering#16
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gokulkrishna98 merged 2 commits intoJun 16, 2026
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Register a lowering for aten.masked_scatter.default. Semantics:
out = self.clone()
out[mask] = source.flatten()[: mask.sum()]
Implementation flattens self/mask/source, then for each flat position
picks from source[cumsum(mask) - 1] if mask is True else self. False
positions select away the gathered values via where(), so out-of-range
indices there are harmless. Indices for True positions are guaranteed
in [0, mask.sum() - 1] by construction.
Supports dynamic shapes by reshaping with the runtime shape vector
(coreai.get_shape) instead of the type-level shape, which carries a
sentinel for unknown dims, and by using -1 in the flat reshapes to
let coreai.reshape infer the numel. Mask broadcast also routes
through the runtime shape when self is dynamic.
Adds TestMaskedScatter covering:
- Static and dynamic IR FileCheck (full operand chain pinned for
static; op order asserted for dynamic).
- Numerical validation across {f32, f16, i32} × {static, dynamic}.
- Corner cases: all-False mask (output == self), all-True mask
(output == src reshape), src larger than mask.sum() (extras
unused), and a lower-rank mask that broadcasts right-aligned
onto self.
Lewis300
approved these changes
Jun 16, 2026
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Description:
Testing: