v0.2.3

• Faster fast and double-fast match finding (levels -131072 to 4).
  Candidate validity is a select between the candidate's bytes and a
  stand-in word that can never match (the reference's
  ZSTD_match4Found_cmov), so only equality branches; this removed most of
  the finders' branch mispredictions. Blocks that cannot read below the
  prefix take a specialization with prefix-relative positions, hash slots
  are held as cell references, and exit tests share the bounds checks of the
  loads they guard. Frames remain byte-identical to zstd 1.5.7.

• Faster lazy finders (greedy to btlazy2). Row tables are viewed from
  a 64-byte boundary as the reference's workspace aligns them (half of the
  tag rows used to straddle cache lines); search state is built once per
  block; the row update checks one range per run and steps through a
  constant table; collected candidates are prefetched as in the reference;
  btlazy2's tree walk counts short runs inline, hands long ones to the
  vector scan, and picks its side without a branch.

• Faster optimal parser (btopt, btultra, btultra2). A per-block
  Finder precomputes the search's parameters, the tree update runs out of
  line, the walk exits early when the first candidate is outside the window,
  hash cells are prefetched four positions ahead, long literal runs refresh
  all literal weights at once, and the position and match tables are sized
  to what a block can use. Levels 16-22 now run faster than zstd 1.5.7 on
  every dataset of the comparison corpus.

• Cheaper sequence coding. fill_codes builds the codes, extra-bit
  counts and the three code histograms in one pass, sequences::encode
  adds each sequence's extra bits with one write when they number fewer
  than 31, and the bit writers and FSE table build drop their bounds checks.
  The sequence encoder now executes fewer instructions than the reference's.

• Updated benchmarks for this working tree
  (2026-10-14): compression median 1.092× zstd 1.5.7 (was 1.000×), faster in
  158 of 192 dataset/level pairs (was 96); decompression median 1.022×, with Alice 0.92× (was 0.89×) and cyclic
  Alice 0.85× (was 0.82×). All frames remain byte-identical to zstd 1.5.7.
  Text at the fastest compression levels and compressible-text decoding
  remain slower than C.

• Faster literal and sequence decoding. Huffman pair tables are built
  from one series per code length with one add per row (3.4x fewer
  instructions), sequence bit counts carry their range so reads need no
  masking, the first chunk of a long-offset match copy and the Huffman fast
  loops' refills need no bounds checks.