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QHash: mark murmurhash() and siphash() hot and never-inline

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Don't allow the compiler to inline them in qHashBits() because they
require a lot of register use and add to the hot code path to aeshash().

Now all calls in this function are tail calls.

Change-Id: I54f205f6b7314351b078fffd16cf7f2f97d99144
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
This commit is contained in:
Thiago Macieira 2022-01-31 15:37:11 -08:00
parent 708de710f1
commit 5be4c5aa0f
1 changed files with 5 additions and 4 deletions
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9
src/corelib/tools/qhash.cpp
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@ -192,7 +192,7 @@ static HashSeedStorage qt_qhash_seed;
* Austin Appleby. See http://murmurhash.googlepages.com/
*/
#if QT_POINTER_SIZE == 4
Q_NEVER_INLINE Q_DECL_HOT_FUNCTION
static inline uint murmurhash(const void *key, uint len, uint seed) noexcept
{
// 'm' and 'r' are mixing constants generated offline.
@ -250,7 +250,7 @@ static inline uint murmurhash(const void *key, uint len, uint seed) noexcept
}
#else
Q_NEVER_INLINE Q_DECL_HOT_FUNCTION
static inline uint64_t murmurhash(const void *key, uint64_t len, uint64_t seed) noexcept
{
const uint64_t m = 0xc6a4a7935bd1e995ULL;
@ -329,7 +329,7 @@ static inline uint64_t murmurhash(const void *key, uint64_t len, uint64_t seed)
v2 = ROTL(v2, 32); \
} while (0)
Q_NEVER_INLINE Q_DECL_HOT_FUNCTION
static uint64_t siphash(const uint8_t *in, uint64_t inlen, uint64_t seed, uint64_t seed2)
{
/* "somepseudorandomlygeneratedbytes" */
@ -434,7 +434,7 @@ static uint64_t siphash(const uint8_t *in, uint64_t inlen, uint64_t seed, uint64
v2 = ROTL(v2, 16); \
} while (0)
Q_NEVER_INLINE Q_DECL_HOT_FUNCTION
static uint siphash(const uint8_t *in, uint inlen, uint seed, uint seed2)
{
/* "somepseudorandomlygeneratedbytes" */
@ -793,6 +793,7 @@ size_t qHashBits(const void *p, size_t size, size_t seed) noexcept
# endif
return aeshash(reinterpret_cast<const uchar *>(p), size, seed, seed2);
#endif
if (size <= QT_POINTER_SIZE)
return murmurhash(p, size, seed);