Niels Lohmann 0c3e83325a Test strings of 8 to 15 characters as one vector ...

The words of a string of 8 to 15 printable ASCII characters were each tested
with the word-at-a-time arithmetic. With SSE2 or NEON, the two overlapping
words are joined into one vector, which takes fewer operations to test; the
stores are unchanged. Targets without either keep the word arithmetic.

Apple M1, Apple clang, retired instructions per dump(), on top of the
previous changes:
  jeopardy 451M -> 430M (-5 %)   citm_catalog 5.60M -> 5.37M (-4 %)
  twitter 3.31M -> 3.25M (-2 %)  keys and values of 1..40 characters -1 %
Linux x86-64 (callgrind), gcc 13 / clang 18: jeopardy -15 % / -7 %,
citm_catalog -6 % / -5 %, twitter -6 % / -4 %.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

2026-10-22 09:28:31 +02:00

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nlohmann

Test strings of 8 to 15 characters as one vector

2026-10-22 09:28:31 +02:00