Re: [RFC] [Discussion] SIMD-Accelerated CRC via crc-fast for ext/hash

On Tue, Feb 17, 2026 at 5:41 AM Michael Wallner <mike@php.net> wrote: > We would like to open the discussion on SIMD-Accelerated CRC via > crc-fast for ext/hash. > > RFC: > https://wiki.php.net/rfc/crc-fast > > PR: > https://github.com/php/php-src/pull/20513 > My initial reaction on seeing this RFC (just browsing wiki.php.net/rfc, not from the email) was "Why give this a new name?" Would it be too onerous to support transparently upgrading calls to hash('crc32'), hash('crc32b'), and crc32() to just use the faster implementation when available? (P.S. - Luagh/Cry that this library has a flag for our "quirk".) The build system define should provide all the signal we need, but a cached CPU capabilities check could be added for belts and suspenders. Or is there a reason to doubt the reliability of the faster algorithms? My desire here is to make choosing the better option easier than choosing the wrong one. A developer who knows what they're doing can interrogate hash_algos(), but that's harder to cache and misses some of the performance boost in the happy path, and makes it worse in the sad path. -Sara