Speed up Vector.fromList - #188
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Specialize list copying by source type so Float32List/Float64List uses setRange, List<double> skips toDouble(), and other List<num> keeps the generic conversion path. Co-authored-by: Ilia Gyrdymov <gyrdym@users.noreply.github.com>
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Specialize list copying by source type so Float32List/Float64List uses setRange, List<double> skips toDouble(), and other List<num> keeps the generic conversion path.
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Specialize
Vector.fromListcopying by the runtime type of the source list.Previously every element went through
List<num>indexing plustoDouble(), including when the source was already aFloat32List/Float64ListorList<double>. That kept the copy loop polymorphic and forced an extra conversion even when it was unnecessary.The constructor now dispatches to typed helpers:
Float32List/Float64List:setRange(contiguous copy)List<double>: direct assignment, notoDouble()List<num>: existingtoDouble()pathOn 10,000,000 elements, mixed-type runs in one isolate went from ~62/72/87 ms (
List<double>/ typed list /List<int>) to ~51/29/32 ms. Official 1e8-element benchmarks:List<double>5.4s,Float32List1.9s.Float64x2Vectorwas regenerated from theFloat32x4Vectortemplate. Version bumped to 13.12.9.