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Optimize break patterns

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This commit is contained in:
zhangyunhao 2023-02-22 16:02:35 +00:00
parent 3b4d6e0804
commit e107ca0f0b
1 changed files with 14 additions and 10 deletions
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24
library/core/src/slice/sort.rs
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@ -673,19 +673,23 @@ where
fn break_patterns<T>(v: &mut [T]) {
let len = v.len();
if len >= 8 {
// Pseudorandom number generator from the "Xorshift RNGs" paper by George Marsaglia.
let mut random = len as u32;
let mut gen_u32 = || {
random ^= random << 13;
random ^= random >> 17;
random ^= random << 5;
random
};
let mut seed = len;
let mut gen_usize = || {
// Pseudorandom number generator from the "Xorshift RNGs" paper by George Marsaglia.
if usize::BITS <= 32 {
gen_u32() as usize
let mut r = seed as u32;
r ^= r << 13;
r ^= r >> 17;
r ^= r << 5;
seed = r as usize;
seed
} else {
(((gen_u32() as u64) << 32) | (gen_u32() as u64)) as usize
let mut r = seed as u64;
r ^= r << 13;
r ^= r >> 7;
r ^= r << 17;
seed = r as usize;
seed
}
};