diff --git a/include/fast_float/ascii_number.h b/include/fast_float/ascii_number.h index 12c2fddc..1c9c8575 100644 --- a/include/fast_float/ascii_number.h +++ b/include/fast_float/ascii_number.h @@ -266,6 +266,21 @@ loop_parse_if_eight_digits(char const *&p, char const *const pend, p)); // in rare cases, this will overflow, but that's ok p += 8; } + // Consume a remaining 4-7 digit run in a single SWAR step instead of + // byte-by-byte (reuses the existing 4-digit helpers). The parsed result is + // identical either way. Gated to clang: on gcc the extra 4-digit check + // regresses inputs whose remainder is shorter than 4 digits (it becomes pure + // overhead there); clang does not show that. +#if defined(__clang__) + if ((pend - p) >= 4) { + uint32_t const val4 = read4_to_u32(p); + if (is_made_of_four_digits_fast(val4)) { + i = i * 10000 + + parse_four_digits_unrolled(val4); // may overflow, that's ok + p += 4; + } + } +#endif } enum class parse_error {