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Load 8 bytes at a time in hash_func. (Sebastian Pop)

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Dmitry Stogov 2019-05-13 12:34:53 +03:00
parent bec6ff9021
commit 071793a0bb
1 changed files with 20 additions and 0 deletions
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20
Zend/zend_string.h
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@ -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 =