com php-src: Load 8 bytes at a time in hash_func. (Seba stian Pop): Zend/zend_string.h

Commit: 071793a0bb278559c32efefbde180727aa312856 Author: Dmitry Stogov <dmitry@zend.com> Mon, 13 May 2019 12:34:53 +0300 Parents: bec6ff90217376baeaf7114359c5273933cbeeca Branches: PHP-7.4 Link: http://git.php.net/?p=php-src.git;a=commitdiff;h=071793a0bb278559c32efefbde180727aa312856 Log: Load 8 bytes at a time in hash_func. (Sebastian Pop) Changed paths: M Zend/zend_string.h Diff: diff --git a/Zend/zend_string.h b/Zend/zend_string.h index 793a519..4fb3e3b 100644 --- a/Zend/zend_string.h +++ b/Zend/zend_string.h @@ -364,6 +364,25 @@ static zend_always_inline zend_ulong zend_inline_hash_func(const char *str, size #if defined(_WIN32) || defined(__i386__) || defined(__x86_64__) || defined(__aarch64__) /* Version with multiplication works better on modern CPU */ for (; len >= 8; len -= 8, str += 8) { +# if defined(__aarch64__) + /* On some architectures it is beneficial to load 8 bytes at a + time and extract each byte with a bit field extract instr. */ + uint64_t chunk; + + memcpy(&chunk, str, sizeof(chunk)); + hash = + hash * 33 * 33 * 33 * 33 + + ((chunk >> (8 * 0)) & 0xff) * 33 * 33 * 33 + + ((chunk >> (8 * 1)) & 0xff) * 33 * 33 + + ((chunk >> (8 * 2)) & 0xff) * 33 + + ((chunk >> (8 * 3)) & 0xff); + hash = + hash * 33 * 33 * 33 * 33 + + ((chunk >> (8 * 4)) & 0xff) * 33 * 33 * 33 + + ((chunk >> (8 * 5)) & 0xff) * 33 * 33 + + ((chunk >> (8 * 6)) & 0xff) * 33 + + ((chunk >> (8 * 7)) & 0xff); +# else hash = hash * 33 * 33 * 33 * 33 + str[0] * 33 * 33 * 33 + @@ -376,6 +395,7 @@ static zend_always_inline zend_ulong zend_inline_hash_func(const char *str, size str[5] * 33 * 33 + str[6] * 33 + str[7]; +# endif } if (len >= 4) { hash =