Files
flatbuffers/rust
Richard Patel 0b60686e3d rust: impl TrustedLen for VectorIter (#8797)
Improves unpack performance for vectors by allowing the compiler
to vectorize flatbuffers::Vector to std::vec::Vec conversions,
using the unstable trusted_len feature.

Internally, enables an optimization in src/alloc/vec/spec_extend.rs:
Previously, unpacking a flatbuffers::Vector called
SpecExtend::extend_desugared fallback, which inhibits vectorization
(due to a branch before every element move).  Declaring TrustedLen
allows SpecExtend::extend_trusted, which LLVM can often vectorize
into a memcpy.

For [ubyte] vectors in particular, this turns a rather expensive
loop of 'mov BYTE PTR [rax+r13*1], bpl' into a `call memcpy`.
2025-12-03 04:21:16 +00:00
..
2025-09-23 21:50:27 -07:00