[libc++] Optimize ranges::copy{, _n} for vector<bool>::iterator (#121013)
This PR optimizes the performance of `std::ranges::copy` and
`std::ranges::copy_n` specifically for `vector<bool>::iterator`,
addressing a subtask outlined in issue #64038. The optimizations yield
performance improvements of up to **2000x** for aligned copies and
**60x** for unaligned copies. Additionally, new tests have been added to
validate these enhancements.
- Aligned source-destination bits
ranges::copy
```
--------------------------------------------------------------------------
Benchmark Before After Improvement
--------------------------------------------------------------------------
bm_ranges_copy_vb_aligned/8 10.8 ns 1.42 ns 8x
bm_ranges_copy_vb_aligned/64 88.5 ns 2.28 ns 39x
bm_ranges_copy_vb_aligned/512 709 ns 1.95 ns 364x
bm_ranges_copy_vb_aligned/4096 5568 ns 5.01 ns 1111x
bm_ranges_copy_vb_aligned/32768 44754 ns 38.7 ns 1156x
bm_ranges_copy_vb_aligned/65536 91092 ns 73.2 ns 1244x
bm_ranges_copy_vb_aligned/102400 139473 ns 127 ns 1098x
bm_ranges_copy_vb_aligned/106496 189004 ns 81.5 ns 2319x
bm_ranges_copy_vb_aligned/110592 153647 ns 71.1 ns 2161x
bm_ranges_copy_vb_aligned/114688 159261 ns 70.2 ns 2269x
bm_ranges_copy_vb_aligned/118784 181910 ns 73.5 ns 2475x
bm_ranges_copy_vb_aligned/122880 174117 ns 76.5 ns 2276x
bm_ranges_copy_vb_aligned/126976 176020 ns 82.0 ns 2147x
bm_ranges_copy_vb_aligned/131072 180757 ns 137 ns 1319x
bm_ranges_copy_vb_aligned/135168 190342 ns 158 ns 1205x
bm_ranges_copy_vb_aligned/139264 192831 ns 103 ns 1872x
bm_ranges_copy_vb_aligned/143360 199627 ns 89.4 ns 2233x
bm_ranges_copy_vb_aligned/147456 203881 ns 88.6 ns 2301x
bm_ranges_copy_vb_aligned/151552 213345 ns 88.4 ns 2413x
bm_ranges_copy_vb_aligned/155648 216892 ns 92.9 ns 2335x
bm_ranges_copy_vb_aligned/159744 222751 ns 96.4 ns 2311x
bm_ranges_copy_vb_aligned/163840 225995 ns 173 ns 1306x
bm_ranges_copy_vb_aligned/167936 235230 ns 202 ns 1165x
bm_ranges_copy_vb_aligned/172032 244093 ns 131 ns 1863x
bm_ranges_copy_vb_aligned/176128 244434 ns 111 ns 2202x
bm_ranges_copy_vb_aligned/180224 249570 ns 108 ns 2311x
bm_ranges_copy_vb_aligned/184320 254538 ns 108 ns 2357x
bm_ranges_copy_vb_aligned/188416 261817 ns 113 ns 2317x
bm_ranges_copy_vb_aligned/192512 269923 ns 125 ns 2159x
bm_ranges_copy_vb_aligned/196608 273494 ns 210 ns 1302x
bm_ranges_copy_vb_aligned/200704 280035 ns 269 ns 1041x
bm_ranges_copy_vb_aligned/204800 293102 ns 231 ns 1269x
```
ranges::copy_n
```
--------------------------------------------------------------------------
Benchmark Before After Improvement
--------------------------------------------------------------------------
bm_ranges_copy_n_vb_aligned/8 11.8 ns 0.89 ns 13x
bm_ranges_copy_n_vb_aligned/64 91.6 ns 2.06 ns 44x
bm_ranges_copy_n_vb_aligned/512 718 ns 2.45 ns 293x
bm_ranges_copy_n_vb_aligned/4096 5750 ns 5.02 ns 1145x
bm_ranges_copy_n_vb_aligned/32768 45824 ns 40.9 ns 1120x
bm_ranges_copy_n_vb_aligned/65536 92267 ns 73.8 ns 1250x
bm_ranges_copy_n_vb_aligned/102400 143267 ns 125 ns 1146x
bm_ranges_copy_n_vb_aligned/106496 148625 ns 82.4 ns 1804x
bm_ranges_copy_n_vb_aligned/110592 154817 ns 72.0 ns 2150x
bm_ranges_copy_n_vb_aligned/114688 157953 ns 70.4 ns 2244x
bm_ranges_copy_n_vb_aligned/118784 162374 ns 71.5 ns 2270x
bm_ranges_copy_n_vb_aligned/122880 168638 ns 72.9 ns 2313x
bm_ranges_copy_n_vb_aligned/126976 175596 ns 76.6 ns 2292x
bm_ranges_copy_n_vb_aligned/131072 181164 ns 135 ns 1342x
bm_ranges_copy_n_vb_aligned/135168 184697 ns 157 ns 1176x
bm_ranges_copy_n_vb_aligned/139264 191395 ns 104 ns 1840x
bm_ranges_copy_n_vb_aligned/143360 194954 ns 88.3 ns 2208x
bm_ranges_copy_n_vb_aligned/147456 208917 ns 86.1 ns 2426x
bm_ranges_copy_n_vb_aligned/151552 211101 ns 87.2 ns 2421x
bm_ranges_copy_n_vb_aligned/155648 213175 ns 89.0 ns 2395x
bm_ranges_copy_n_vb_aligned/159744 218988 ns 86.7 ns 2526x
bm_ranges_copy_n_vb_aligned/163840 225263 ns 156 ns 1444x
bm_ranges_copy_n_vb_aligned/167936 230725 ns 184 ns 1254x
bm_ranges_copy_n_vb_aligned/172032 235795 ns 119 ns 1981x
bm_ranges_copy_n_vb_aligned/176128 241145 ns 101 ns 2388x
bm_ranges_copy_n_vb_aligned/180224 250680 ns 99.5 ns 2519x
bm_ranges_copy_n_vb_aligned/184320 262954 ns 99.7 ns 2637x
bm_ranges_copy_n_vb_aligned/188416 258584 ns 103 ns 2510x
bm_ranges_copy_n_vb_aligned/192512 267190 ns 125 ns 2138x
bm_ranges_copy_n_vb_aligned/196608 270821 ns 213 ns 1271x
bm_ranges_copy_n_vb_aligned/200704 279532 ns 262 ns 1067x
bm_ranges_copy_n_vb_aligned/204800 283412 ns 222 ns 1277x
```
- Unaligned source-destination bits
```
--------------------------------------------------------------------------------
Benchmark Before After Improvement
--------------------------------------------------------------------------------
bm_ranges_copy_vb_unaligned/8 12.8 ns 8.59 ns 1.5x
bm_ranges_copy_vb_unaligned/64 98.2 ns 8.24 ns 12x
bm_ranges_copy_vb_unaligned/512 755 ns 18.1 ns 42x
bm_ranges_copy_vb_unaligned/4096 6027 ns 102 ns 59x
bm_ranges_copy_vb_unaligned/32768 47663 ns 774 ns 62x
bm_ranges_copy_vb_unaligned/262144 378981 ns 6455 ns 59x
bm_ranges_copy_vb_unaligned/1048576 1520486 ns 25942 ns 59x
bm_ranges_copy_n_vb_unaligned/8 11.3 ns 8.22 ns 1.4x
bm_ranges_copy_n_vb_unaligned/64 97.3 ns 7.89 ns 12x
bm_ranges_copy_n_vb_unaligned/512 747 ns 18.1 ns 41x
bm_ranges_copy_n_vb_unaligned/4096 5932 ns 99.0 ns 60x
bm_ranges_copy_n_vb_unaligned/32768 47776 ns 749 ns 64x
bm_ranges_copy_n_vb_unaligned/262144 378802 ns 6576 ns 58x
bm_ranges_copy_n_vb_unaligned/1048576 1547234 ns 26229 ns 59x
```
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