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improve popcount

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This commit is contained in:
daanx 2024-12-10 14:50:55 -08:00
parent f37aff6ee2
commit 7cd8f31f30
2 changed files with 27 additions and 25 deletions
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48
include/mimalloc/bits.h
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@ -144,11 +144,31 @@ typedef int32_t mi_ssize_t;
#define mi_msc_builtinz(name) name##64
#endif
/* --------------------------------------------------------------------------------
Count trailing/leading zero's
Popcount and count trailing/leading zero's
-------------------------------------------------------------------------------- */
size_t _mi_popcount_generic(size_t x);
static inline size_t mi_popcount(size_t x) {
#if mi_has_builtinz(popcount)
return mi_builtinz(popcount)(x);
#elif defined(_MSC_VER) && (MI_ARCH_X64 || MI_ARCH_X86 || MI_ARCH_ARM64 || MI_ARCH_ARM32)
return mi_msc_builtinz(__popcnt)(x);
#elif MI_ARCH_X64 && defined(__BMI1__)
return (size_t)_mm_popcnt_u64(x);
#else
#define MI_HAS_FAST_POPCOUNT 0
return (x<=1 ? x : _mi_popcount_generic(x));
#endif
}
#ifndef MI_HAS_FAST_POPCOUNT
#define MI_HAS_FAST_POPCOUNT 1
#endif
size_t _mi_clz_generic(size_t x);
size_t _mi_ctz_generic(size_t x);
@ -169,6 +189,8 @@ static inline size_t mi_ctz(size_t x) {
size_t r;
__asm ("bsf\t%1, %0" : "=r"(r) : "r"(x) : "cc");
return r;
#elif MI_HAS_FAST_POPCOUNT
return (x!=0 ? (mi_popcount(x^(x-1))-1) : MI_SIZE_BITS);
#else
#define MI_HAS_FAST_BITSCAN 0
return (x!=0 ? _mi_ctz_generic(x) : MI_SIZE_BITS);
@ -179,7 +201,7 @@ static inline size_t mi_clz(size_t x) {
#if defined(__GNUC__) && MI_ARCH_X64 && defined(__BMI1__) // on x64 lzcnt is defined for 0
size_t r;
__asm ("lzcnt\t%1, %0" : "=r"(r) : "r"(x) : "cc");
return r;
return r;
#elif MI_ARCH_X64 && defined(__BMI1__)
return (size_t)_lzcnt_u64(x);
#elif defined(_MSC_VER) && (MI_ARCH_X64 || MI_ARCH_X86 || MI_ARCH_ARM64 || MI_ARCH_ARM32)
@ -202,26 +224,6 @@ static inline size_t mi_clz(size_t x) {
#define MI_HAS_FAST_BITSCAN 1
#endif
size_t _mi_popcount_generic(size_t x);
static inline size_t mi_popcount(size_t x) {
#if mi_has_builtinz(popcount)
return mi_builtinz(popcount)(x);
#elif defined(_MSC_VER) && (MI_ARCH_X64 || MI_ARCH_X86 || MI_ARCH_ARM64 || MI_ARCH_ARM32)
return mi_msc_builtinz(__popcnt)(x);
#elif MI_ARCH_X64 && defined(__BMI1__)
return (size_t)_mm_popcnt_u64(x);
#else
#define MI_HAS_FAST_POPCOUNT 0
return (x<=1 ? x : _mi_popcount_generic(x));
#endif
}
#ifndef MI_HAS_FAST_POPCOUNT
#define MI_HAS_FAST_POPCOUNT 1
#endif
/* --------------------------------------------------------------------------------
find trailing/leading zero (bit scan forward/reverse)
-------------------------------------------------------------------------------- */