Reapply "[libc++] Simplify the implementation of std::sort a bit (#104902)" (#114023)

This reverts commit ef44e4659878f2. The patch was originally reverted
because it was
deemed to introduce a perfo

Reapply "[libc++] Simplify the implementation of std::sort a bit (#104902)" (#114023)

This reverts commit ef44e4659878f2. The patch was originally reverted
because it was
deemed to introduce a performance regression for small inputs, however
it also fixed
a previous performance regression for larger inputs. So overall, this
patch is desirable.

show more ...

Revert "[libc++] Simplify the implementation of std::sort a bit (#104902)"

This reverts commit d4ffccfce103b01401b8a9222e373f2d404f8439, which
caused a performance regression that needs to be invest

Revert "[libc++] Simplify the implementation of std::sort a bit (#104902)"

This reverts commit d4ffccfce103b01401b8a9222e373f2d404f8439, which
caused a performance regression that needs to be investigated further.

show more ...

[libc++] Simplify the implementation of std::sort a bit (#104902)

This does a few things to canonicalize the library a bit. Specifically
- use `__desugars_to_v` instead of the custom `__is_simple_c

[libc++] Simplify the implementation of std::sort a bit (#104902)

This does a few things to canonicalize the library a bit. Specifically
- use `__desugars_to_v` instead of the custom `__is_simple_comparator`
- make `__use_branchless_sort` an inline variable
- remove the `_maybe_branchless` versions of the `__sortN` functions and
overload based on whether we can do branchless sorting instead.

show more ...

[libc++] Optimize lexicographical_compare (#65279)

If the comparison operation is equivalent to < and that is a total
order, we know that we can use equality comparison on that type instead
to ext

[libc++] Optimize lexicographical_compare (#65279)

If the comparison operation is equivalent to < and that is a total
order, we know that we can use equality comparison on that type instead
to extract some information. Furthermore, if equality comparison on that
type is trivial, the user can't observe that we're calling it. So
instead of using the user-provided total order, we use std::mismatch,
which uses equality comparison (and is vertorized). Additionally, if the
type is trivially lexicographically comparable, we can go one step
further and use std::memcmp directly instead of calling std::mismatch.

Benchmarks:
```
-------------------------------------------------------------------------------------
Benchmark old new
-------------------------------------------------------------------------------------
bm_lexicographical_compare<unsigned char>/1 1.17 ns 2.34 ns
bm_lexicographical_compare<unsigned char>/2 1.64 ns 2.57 ns
bm_lexicographical_compare<unsigned char>/3 2.23 ns 2.58 ns
bm_lexicographical_compare<unsigned char>/4 2.82 ns 2.57 ns
bm_lexicographical_compare<unsigned char>/5 3.34 ns 2.11 ns
bm_lexicographical_compare<unsigned char>/6 3.94 ns 2.21 ns
bm_lexicographical_compare<unsigned char>/7 4.56 ns 2.11 ns
bm_lexicographical_compare<unsigned char>/8 5.25 ns 2.11 ns
bm_lexicographical_compare<unsigned char>/16 9.88 ns 2.11 ns
bm_lexicographical_compare<unsigned char>/64 38.9 ns 2.36 ns
bm_lexicographical_compare<unsigned char>/512 317 ns 6.54 ns
bm_lexicographical_compare<unsigned char>/4096 2517 ns 41.4 ns
bm_lexicographical_compare<unsigned char>/32768 20052 ns 488 ns
bm_lexicographical_compare<unsigned char>/262144 159579 ns 4409 ns
bm_lexicographical_compare<unsigned char>/1048576 640456 ns 20342 ns
bm_lexicographical_compare<signed char>/1 1.18 ns 2.37 ns
bm_lexicographical_compare<signed char>/2 1.65 ns 2.60 ns
bm_lexicographical_compare<signed char>/3 2.23 ns 2.83 ns
bm_lexicographical_compare<signed char>/4 2.81 ns 3.06 ns
bm_lexicographical_compare<signed char>/5 3.35 ns 3.30 ns
bm_lexicographical_compare<signed char>/6 3.90 ns 3.99 ns
bm_lexicographical_compare<signed char>/7 4.56 ns 3.78 ns
bm_lexicographical_compare<signed char>/8 5.20 ns 4.02 ns
bm_lexicographical_compare<signed char>/16 9.80 ns 6.21 ns
bm_lexicographical_compare<signed char>/64 39.0 ns 3.16 ns
bm_lexicographical_compare<signed char>/512 318 ns 7.58 ns
bm_lexicographical_compare<signed char>/4096 2514 ns 47.4 ns
bm_lexicographical_compare<signed char>/32768 20096 ns 504 ns
bm_lexicographical_compare<signed char>/262144 156617 ns 4146 ns
bm_lexicographical_compare<signed char>/1048576 624265 ns 19810 ns
bm_lexicographical_compare<int>/1 1.15 ns 2.12 ns
bm_lexicographical_compare<int>/2 1.60 ns 2.36 ns
bm_lexicographical_compare<int>/3 2.21 ns 2.59 ns
bm_lexicographical_compare<int>/4 2.74 ns 2.83 ns
bm_lexicographical_compare<int>/5 3.26 ns 3.06 ns
bm_lexicographical_compare<int>/6 3.81 ns 4.53 ns
bm_lexicographical_compare<int>/7 4.41 ns 4.72 ns
bm_lexicographical_compare<int>/8 5.08 ns 2.36 ns
bm_lexicographical_compare<int>/16 9.54 ns 3.08 ns
bm_lexicographical_compare<int>/64 37.8 ns 4.71 ns
bm_lexicographical_compare<int>/512 309 ns 24.6 ns
bm_lexicographical_compare<int>/4096 2422 ns 204 ns
bm_lexicographical_compare<int>/32768 19362 ns 1947 ns
bm_lexicographical_compare<int>/262144 155727 ns 19793 ns
bm_lexicographical_compare<int>/1048576 623614 ns 80180 ns
bm_ranges_lexicographical_compare<unsigned char>/1 1.07 ns 2.35 ns
bm_ranges_lexicographical_compare<unsigned char>/2 1.72 ns 2.13 ns
bm_ranges_lexicographical_compare<unsigned char>/3 2.46 ns 2.12 ns
bm_ranges_lexicographical_compare<unsigned char>/4 3.17 ns 2.12 ns
bm_ranges_lexicographical_compare<unsigned char>/5 3.86 ns 2.12 ns
bm_ranges_lexicographical_compare<unsigned char>/6 4.55 ns 2.12 ns
bm_ranges_lexicographical_compare<unsigned char>/7 5.25 ns 2.12 ns
bm_ranges_lexicographical_compare<unsigned char>/8 5.95 ns 2.13 ns
bm_ranges_lexicographical_compare<unsigned char>/16 11.7 ns 2.13 ns
bm_ranges_lexicographical_compare<unsigned char>/64 45.5 ns 2.36 ns
bm_ranges_lexicographical_compare<unsigned char>/512 366 ns 6.35 ns
bm_ranges_lexicographical_compare<unsigned char>/4096 2886 ns 40.9 ns
bm_ranges_lexicographical_compare<unsigned char>/32768 23054 ns 489 ns
bm_ranges_lexicographical_compare<unsigned char>/262144 185302 ns 4339 ns
bm_ranges_lexicographical_compare<unsigned char>/1048576 741576 ns 19430 ns
bm_ranges_lexicographical_compare<signed char>/1 1.10 ns 2.12 ns
bm_ranges_lexicographical_compare<signed char>/2 1.66 ns 2.35 ns
bm_ranges_lexicographical_compare<signed char>/3 2.23 ns 2.58 ns
bm_ranges_lexicographical_compare<signed char>/4 2.82 ns 2.82 ns
bm_ranges_lexicographical_compare<signed char>/5 3.34 ns 3.06 ns
bm_ranges_lexicographical_compare<signed char>/6 3.92 ns 3.99 ns
bm_ranges_lexicographical_compare<signed char>/7 4.64 ns 4.10 ns
bm_ranges_lexicographical_compare<signed char>/8 5.21 ns 4.61 ns
bm_ranges_lexicographical_compare<signed char>/16 9.79 ns 7.42 ns
bm_ranges_lexicographical_compare<signed char>/64 38.9 ns 2.93 ns
bm_ranges_lexicographical_compare<signed char>/512 317 ns 7.31 ns
bm_ranges_lexicographical_compare<signed char>/4096 2500 ns 47.5 ns
bm_ranges_lexicographical_compare<signed char>/32768 19940 ns 496 ns
bm_ranges_lexicographical_compare<signed char>/262144 159166 ns 4393 ns
bm_ranges_lexicographical_compare<signed char>/1048576 638206 ns 19786 ns
bm_ranges_lexicographical_compare<int>/1 1.10 ns 2.12 ns
bm_ranges_lexicographical_compare<int>/2 1.64 ns 3.04 ns
bm_ranges_lexicographical_compare<int>/3 2.23 ns 2.58 ns
bm_ranges_lexicographical_compare<int>/4 2.81 ns 2.81 ns
bm_ranges_lexicographical_compare<int>/5 3.35 ns 3.05 ns
bm_ranges_lexicographical_compare<int>/6 3.94 ns 4.60 ns
bm_ranges_lexicographical_compare<int>/7 4.60 ns 4.81 ns
bm_ranges_lexicographical_compare<int>/8 5.19 ns 2.35 ns
bm_ranges_lexicographical_compare<int>/16 9.85 ns 2.87 ns
bm_ranges_lexicographical_compare<int>/64 38.9 ns 4.70 ns
bm_ranges_lexicographical_compare<int>/512 318 ns 24.5 ns
bm_ranges_lexicographical_compare<int>/4096 2494 ns 202 ns
bm_ranges_lexicographical_compare<int>/32768 20000 ns 1939 ns
bm_ranges_lexicographical_compare<int>/262144 160433 ns 19730 ns
bm_ranges_lexicographical_compare<int>/1048576 642636 ns 80760 ns
```

show more ...

[libc++] Optimize ranges::minmax (#87335)

This allows Clang to vectorize the loop.
```
---------------------------------------------------------------------
Benchmark

[libc++] Optimize ranges::minmax (#87335)

This allows Clang to vectorize the loop.
```
---------------------------------------------------------------------
Benchmark old new
---------------------------------------------------------------------
BM_std_minmax<char>/1 0.659 ns 1.41 ns
BM_std_minmax<char>/2 1.08 ns 2.16 ns
BM_std_minmax<char>/3 2.16 ns 2.96 ns
BM_std_minmax<char>/4 2.82 ns 3.81 ns
BM_std_minmax<char>/5 3.43 ns 4.69 ns
BM_std_minmax<char>/6 4.08 ns 5.63 ns
BM_std_minmax<char>/7 4.75 ns 6.51 ns
BM_std_minmax<char>/8 5.42 ns 7.41 ns
BM_std_minmax<char>/9 6.05 ns 8.34 ns
BM_std_minmax<char>/10 6.68 ns 9.29 ns
BM_std_minmax<char>/11 7.47 ns 10.6 ns
BM_std_minmax<char>/12 7.95 ns 11.4 ns
BM_std_minmax<char>/13 8.64 ns 12.4 ns
BM_std_minmax<char>/14 9.35 ns 13.4 ns
BM_std_minmax<char>/15 10.1 ns 14.4 ns
BM_std_minmax<char>/16 10.6 ns 2.25 ns
BM_std_minmax<char>/17 11.3 ns 2.82 ns
BM_std_minmax<char>/18 11.8 ns 3.71 ns
BM_std_minmax<char>/19 12.6 ns 4.52 ns
BM_std_minmax<char>/20 13.2 ns 5.47 ns
BM_std_minmax<char>/21 14.1 ns 6.67 ns
BM_std_minmax<char>/22 14.5 ns 7.78 ns
BM_std_minmax<char>/23 15.1 ns 8.67 ns
BM_std_minmax<char>/24 15.7 ns 9.68 ns
BM_std_minmax<char>/25 16.4 ns 10.7 ns
BM_std_minmax<char>/26 17.1 ns 11.7 ns
BM_std_minmax<char>/27 17.8 ns 12.8 ns
BM_std_minmax<char>/28 18.4 ns 14.1 ns
BM_std_minmax<char>/29 19.0 ns 15.0 ns
BM_std_minmax<char>/30 19.6 ns 16.0 ns
BM_std_minmax<char>/31 20.2 ns 17.0 ns
BM_std_minmax<char>/32 20.8 ns 2.46 ns
BM_std_minmax<char>/64 41.5 ns 2.97 ns
BM_std_minmax<char>/512 340 ns 6.05 ns
BM_std_minmax<char>/1024 667 ns 8.83 ns
BM_std_minmax<char>/4000 2571 ns 28.6 ns
BM_std_minmax<char>/4096 2632 ns 25.8 ns
BM_std_minmax<char>/5500 3554 ns 51.1 ns
BM_std_minmax<char>/64000 41175 ns 480 ns
BM_std_minmax<char>/65536 42039 ns 490 ns
BM_std_minmax<char>/70000 44931 ns 528 ns
BM_std_minmax<short>/1 0.708 ns 1.20 ns
BM_std_minmax<short>/2 1.18 ns 1.78 ns
BM_std_minmax<short>/3 1.98 ns 2.42 ns
BM_std_minmax<short>/4 2.47 ns 3.05 ns
BM_std_minmax<short>/5 3.09 ns 3.72 ns
BM_std_minmax<short>/6 3.49 ns 4.37 ns
BM_std_minmax<short>/7 4.24 ns 5.03 ns
BM_std_minmax<short>/8 4.65 ns 2.12 ns
BM_std_minmax<short>/9 5.34 ns 2.51 ns
BM_std_minmax<short>/10 5.82 ns 3.18 ns
BM_std_minmax<short>/11 6.36 ns 3.97 ns
BM_std_minmax<short>/12 6.73 ns 4.68 ns
BM_std_minmax<short>/13 7.59 ns 5.49 ns
BM_std_minmax<short>/14 7.77 ns 6.45 ns
BM_std_minmax<short>/15 8.54 ns 7.55 ns
BM_std_minmax<short>/16 8.74 ns 2.38 ns
BM_std_minmax<short>/17 9.59 ns 2.76 ns
BM_std_minmax<short>/18 9.88 ns 3.37 ns
BM_std_minmax<short>/19 10.7 ns 4.17 ns
BM_std_minmax<short>/20 10.9 ns 4.88 ns
BM_std_minmax<short>/21 12.1 ns 5.70 ns
BM_std_minmax<short>/22 12.6 ns 6.64 ns
BM_std_minmax<short>/23 13.5 ns 7.72 ns
BM_std_minmax<short>/24 13.2 ns 2.87 ns
BM_std_minmax<short>/25 14.2 ns 3.10 ns
BM_std_minmax<short>/26 14.2 ns 3.59 ns
BM_std_minmax<short>/27 15.4 ns 4.35 ns
BM_std_minmax<short>/28 15.3 ns 5.10 ns
BM_std_minmax<short>/29 16.2 ns 5.87 ns
BM_std_minmax<short>/30 16.2 ns 6.88 ns
BM_std_minmax<short>/31 17.0 ns 7.78 ns
BM_std_minmax<short>/32 17.2 ns 3.45 ns
BM_std_minmax<short>/64 34.1 ns 3.35 ns
BM_std_minmax<short>/512 279 ns 8.37 ns
BM_std_minmax<short>/1024 549 ns 14.2 ns
BM_std_minmax<short>/4000 2111 ns 50.1 ns
BM_std_minmax<short>/4096 2167 ns 47.9 ns
BM_std_minmax<short>/5500 2895 ns 69.7 ns
BM_std_minmax<short>/64000 33454 ns 953 ns
BM_std_minmax<short>/65536 34474 ns 970 ns
BM_std_minmax<short>/70000 36691 ns 1037 ns
BM_std_minmax<int>/1 0.664 ns 1.17 ns
BM_std_minmax<int>/2 1.11 ns 1.69 ns
BM_std_minmax<int>/3 2.36 ns 2.29 ns
BM_std_minmax<int>/4 2.53 ns 2.91 ns
BM_std_minmax<int>/5 3.23 ns 3.56 ns
BM_std_minmax<int>/6 3.56 ns 4.23 ns
BM_std_minmax<int>/7 4.28 ns 4.91 ns
BM_std_minmax<int>/8 4.60 ns 5.60 ns
BM_std_minmax<int>/9 5.38 ns 6.31 ns
BM_std_minmax<int>/10 5.69 ns 7.03 ns
BM_std_minmax<int>/11 6.41 ns 7.70 ns
BM_std_minmax<int>/12 6.73 ns 8.39 ns
BM_std_minmax<int>/13 7.38 ns 9.07 ns
BM_std_minmax<int>/14 7.74 ns 9.79 ns
BM_std_minmax<int>/15 8.53 ns 10.5 ns
BM_std_minmax<int>/16 8.79 ns 11.2 ns
BM_std_minmax<int>/17 9.63 ns 12.0 ns
BM_std_minmax<int>/18 9.84 ns 12.7 ns
BM_std_minmax<int>/19 10.6 ns 13.5 ns
BM_std_minmax<int>/20 11.0 ns 14.3 ns
BM_std_minmax<int>/21 11.7 ns 15.0 ns
BM_std_minmax<int>/22 12.0 ns 15.7 ns
BM_std_minmax<int>/23 13.1 ns 16.5 ns
BM_std_minmax<int>/24 13.0 ns 17.3 ns
BM_std_minmax<int>/25 13.7 ns 17.9 ns
BM_std_minmax<int>/26 14.0 ns 18.6 ns
BM_std_minmax<int>/27 14.8 ns 19.4 ns
BM_std_minmax<int>/28 15.1 ns 20.3 ns
BM_std_minmax<int>/29 15.8 ns 20.9 ns
BM_std_minmax<int>/30 16.1 ns 21.7 ns
BM_std_minmax<int>/31 16.9 ns 22.5 ns
BM_std_minmax<int>/32 17.2 ns 3.40 ns
BM_std_minmax<int>/64 33.9 ns 4.04 ns
BM_std_minmax<int>/512 275 ns 14.6 ns
BM_std_minmax<int>/1024 541 ns 27.5 ns
BM_std_minmax<int>/4000 2093 ns 96.3 ns
BM_std_minmax<int>/4096 2146 ns 98.3 ns
BM_std_minmax<int>/5500 2866 ns 157 ns
BM_std_minmax<int>/64000 33619 ns 1954 ns
BM_std_minmax<int>/65536 34252 ns 2009 ns
BM_std_minmax<int>/70000 36618 ns 2125 ns
BM_std_minmax<long long>/1 0.709 ns 1.19 ns
BM_std_minmax<long long>/2 1.01 ns 1.65 ns
BM_std_minmax<long long>/3 2.14 ns 2.21 ns
BM_std_minmax<long long>/4 2.45 ns 2.83 ns
BM_std_minmax<long long>/5 3.09 ns 3.47 ns
BM_std_minmax<long long>/6 3.44 ns 4.11 ns
BM_std_minmax<long long>/7 4.16 ns 4.79 ns
BM_std_minmax<long long>/8 4.54 ns 5.47 ns
BM_std_minmax<long long>/9 5.37 ns 6.20 ns
BM_std_minmax<long long>/10 5.71 ns 6.93 ns
BM_std_minmax<long long>/11 6.00 ns 7.60 ns
BM_std_minmax<long long>/12 6.43 ns 8.27 ns
BM_std_minmax<long long>/13 7.01 ns 8.94 ns
BM_std_minmax<long long>/14 7.45 ns 9.65 ns
BM_std_minmax<long long>/15 8.16 ns 10.4 ns
BM_std_minmax<long long>/16 8.46 ns 5.22 ns
BM_std_minmax<long long>/17 9.16 ns 5.22 ns
BM_std_minmax<long long>/18 9.53 ns 5.52 ns
BM_std_minmax<long long>/19 10.2 ns 6.02 ns
BM_std_minmax<long long>/20 10.5 ns 6.89 ns
BM_std_minmax<long long>/21 11.3 ns 7.83 ns
BM_std_minmax<long long>/22 11.6 ns 8.59 ns
BM_std_minmax<long long>/23 12.3 ns 9.91 ns
BM_std_minmax<long long>/24 12.6 ns 10.1 ns
BM_std_minmax<long long>/25 13.2 ns 12.0 ns
BM_std_minmax<long long>/26 13.6 ns 13.5 ns
BM_std_minmax<long long>/27 14.2 ns 14.8 ns
BM_std_minmax<long long>/28 14.7 ns 15.9 ns
BM_std_minmax<long long>/29 15.3 ns 16.6 ns
BM_std_minmax<long long>/30 15.8 ns 17.3 ns
BM_std_minmax<long long>/31 16.3 ns 18.2 ns
BM_std_minmax<long long>/32 16.7 ns 7.18 ns
BM_std_minmax<long long>/64 33.1 ns 11.5 ns
BM_std_minmax<long long>/512 268 ns 71.0 ns
BM_std_minmax<long long>/1024 532 ns 138 ns
BM_std_minmax<long long>/4000 2056 ns 533 ns
BM_std_minmax<long long>/4096 2112 ns 539 ns
BM_std_minmax<long long>/5500 2823 ns 749 ns
BM_std_minmax<long long>/64000 32956 ns 8590 ns
BM_std_minmax<long long>/65536 33795 ns 8791 ns
BM_std_minmax<long long>/70000 36084 ns 9442 ns
BM_std_minmax<unsigned char>/1 0.714 ns 1.41 ns
BM_std_minmax<unsigned char>/2 0.955 ns 1.96 ns
BM_std_minmax<unsigned char>/3 1.90 ns 2.63 ns
BM_std_minmax<unsigned char>/4 2.40 ns 3.34 ns
BM_std_minmax<unsigned char>/5 2.87 ns 4.10 ns
BM_std_minmax<unsigned char>/6 3.47 ns 4.88 ns
BM_std_minmax<unsigned char>/7 4.04 ns 5.66 ns
BM_std_minmax<unsigned char>/8 4.65 ns 6.45 ns
BM_std_minmax<unsigned char>/9 5.18 ns 7.24 ns
BM_std_minmax<unsigned char>/10 5.80 ns 8.05 ns
BM_std_minmax<unsigned char>/11 6.24 ns 8.86 ns
BM_std_minmax<unsigned char>/12 6.78 ns 9.70 ns
BM_std_minmax<unsigned char>/13 7.30 ns 10.6 ns
BM_std_minmax<unsigned char>/14 7.86 ns 11.4 ns
BM_std_minmax<unsigned char>/15 8.46 ns 12.3 ns
BM_std_minmax<unsigned char>/16 9.00 ns 2.12 ns
BM_std_minmax<unsigned char>/17 9.58 ns 2.83 ns
BM_std_minmax<unsigned char>/18 10.1 ns 3.37 ns
BM_std_minmax<unsigned char>/19 10.7 ns 4.11 ns
BM_std_minmax<unsigned char>/20 11.2 ns 4.85 ns
BM_std_minmax<unsigned char>/21 11.9 ns 5.69 ns
BM_std_minmax<unsigned char>/22 12.3 ns 6.77 ns
BM_std_minmax<unsigned char>/23 13.1 ns 7.56 ns
BM_std_minmax<unsigned char>/24 13.5 ns 8.40 ns
BM_std_minmax<unsigned char>/25 14.2 ns 9.30 ns
BM_std_minmax<unsigned char>/26 14.4 ns 10.1 ns
BM_std_minmax<unsigned char>/27 15.0 ns 11.1 ns
BM_std_minmax<unsigned char>/28 15.3 ns 11.9 ns
BM_std_minmax<unsigned char>/29 16.2 ns 12.9 ns
BM_std_minmax<unsigned char>/30 16.5 ns 13.9 ns
BM_std_minmax<unsigned char>/31 17.2 ns 14.8 ns
BM_std_minmax<unsigned char>/32 17.6 ns 2.36 ns
BM_std_minmax<unsigned char>/64 35.6 ns 3.21 ns
BM_std_minmax<unsigned char>/512 288 ns 6.00 ns
BM_std_minmax<unsigned char>/1024 573 ns 8.80 ns
BM_std_minmax<unsigned char>/4000 2222 ns 28.6 ns
BM_std_minmax<unsigned char>/4096 2265 ns 25.9 ns
BM_std_minmax<unsigned char>/5500 3047 ns 48.8 ns
BM_std_minmax<unsigned char>/64000 35059 ns 480 ns
BM_std_minmax<unsigned char>/65536 35941 ns 491 ns
BM_std_minmax<unsigned char>/70000 38922 ns 525 ns
BM_std_minmax<unsigned short>/1 0.711 ns 1.18 ns
BM_std_minmax<unsigned short>/2 0.957 ns 1.65 ns
BM_std_minmax<unsigned short>/3 2.13 ns 2.21 ns
BM_std_minmax<unsigned short>/4 2.14 ns 2.78 ns
BM_std_minmax<unsigned short>/5 3.06 ns 3.29 ns
BM_std_minmax<unsigned short>/6 2.89 ns 3.87 ns
BM_std_minmax<unsigned short>/7 3.80 ns 4.55 ns
BM_std_minmax<unsigned short>/8 3.68 ns 2.02 ns
BM_std_minmax<unsigned short>/9 4.53 ns 2.40 ns
BM_std_minmax<unsigned short>/10 4.60 ns 2.94 ns
BM_std_minmax<unsigned short>/11 5.67 ns 3.67 ns
BM_std_minmax<unsigned short>/12 5.39 ns 4.22 ns
BM_std_minmax<unsigned short>/13 6.58 ns 4.78 ns
BM_std_minmax<unsigned short>/14 6.33 ns 5.54 ns
BM_std_minmax<unsigned short>/15 7.34 ns 6.30 ns
BM_std_minmax<unsigned short>/16 7.17 ns 2.25 ns
BM_std_minmax<unsigned short>/17 8.19 ns 2.61 ns
BM_std_minmax<unsigned short>/18 8.02 ns 3.19 ns
BM_std_minmax<unsigned short>/19 9.03 ns 3.72 ns
BM_std_minmax<unsigned short>/20 8.89 ns 4.36 ns
BM_std_minmax<unsigned short>/21 9.77 ns 5.10 ns
BM_std_minmax<unsigned short>/22 9.70 ns 5.55 ns
BM_std_minmax<unsigned short>/23 10.8 ns 6.29 ns
BM_std_minmax<unsigned short>/24 10.6 ns 2.41 ns
BM_std_minmax<unsigned short>/25 11.6 ns 2.75 ns
BM_std_minmax<unsigned short>/26 11.4 ns 3.26 ns
BM_std_minmax<unsigned short>/27 12.4 ns 3.86 ns
BM_std_minmax<unsigned short>/28 12.3 ns 4.45 ns
BM_std_minmax<unsigned short>/29 13.2 ns 5.07 ns
BM_std_minmax<unsigned short>/30 13.1 ns 5.77 ns
BM_std_minmax<unsigned short>/31 13.9 ns 6.65 ns
BM_std_minmax<unsigned short>/32 13.9 ns 2.72 ns
BM_std_minmax<unsigned short>/64 27.8 ns 3.25 ns
BM_std_minmax<unsigned short>/512 220 ns 8.30 ns
BM_std_minmax<unsigned short>/1024 435 ns 14.1 ns
BM_std_minmax<unsigned short>/4000 1703 ns 49.8 ns
BM_std_minmax<unsigned short>/4096 1746 ns 47.9 ns
BM_std_minmax<unsigned short>/5500 2350 ns 69.9 ns
BM_std_minmax<unsigned short>/64000 27388 ns 953 ns
BM_std_minmax<unsigned short>/65536 28040 ns 975 ns
BM_std_minmax<unsigned short>/70000 29967 ns 1040 ns
BM_std_minmax<unsigned int>/1 0.712 ns 1.18 ns
BM_std_minmax<unsigned int>/2 0.965 ns 1.65 ns
BM_std_minmax<unsigned int>/3 2.13 ns 2.14 ns
BM_std_minmax<unsigned int>/4 2.09 ns 2.64 ns
BM_std_minmax<unsigned int>/5 3.02 ns 3.21 ns
BM_std_minmax<unsigned int>/6 2.94 ns 3.81 ns
BM_std_minmax<unsigned int>/7 3.91 ns 4.38 ns
BM_std_minmax<unsigned int>/8 3.75 ns 4.93 ns
BM_std_minmax<unsigned int>/9 4.71 ns 5.60 ns
BM_std_minmax<unsigned int>/10 4.59 ns 6.26 ns
BM_std_minmax<unsigned int>/11 5.57 ns 6.80 ns
BM_std_minmax<unsigned int>/12 5.43 ns 7.47 ns
BM_std_minmax<unsigned int>/13 6.45 ns 8.10 ns
BM_std_minmax<unsigned int>/14 6.32 ns 8.69 ns
BM_std_minmax<unsigned int>/15 7.29 ns 9.37 ns
BM_std_minmax<unsigned int>/16 7.12 ns 9.99 ns
BM_std_minmax<unsigned int>/17 8.24 ns 10.6 ns
BM_std_minmax<unsigned int>/18 8.00 ns 11.2 ns
BM_std_minmax<unsigned int>/19 8.94 ns 12.0 ns
BM_std_minmax<unsigned int>/20 8.91 ns 12.6 ns
BM_std_minmax<unsigned int>/21 9.73 ns 17.2 ns
BM_std_minmax<unsigned int>/22 9.75 ns 13.8 ns
BM_std_minmax<unsigned int>/23 10.6 ns 14.5 ns
BM_std_minmax<unsigned int>/24 10.6 ns 15.1 ns
BM_std_minmax<unsigned int>/25 11.5 ns 15.7 ns
BM_std_minmax<unsigned int>/26 11.4 ns 16.3 ns
BM_std_minmax<unsigned int>/27 12.3 ns 17.0 ns
BM_std_minmax<unsigned int>/28 12.3 ns 17.6 ns
BM_std_minmax<unsigned int>/29 13.2 ns 18.3 ns
BM_std_minmax<unsigned int>/30 13.2 ns 19.0 ns
BM_std_minmax<unsigned int>/31 14.0 ns 19.6 ns
BM_std_minmax<unsigned int>/32 14.0 ns 3.39 ns
BM_std_minmax<unsigned int>/64 27.6 ns 4.05 ns
BM_std_minmax<unsigned int>/512 221 ns 14.2 ns
BM_std_minmax<unsigned int>/1024 439 ns 25.5 ns
BM_std_minmax<unsigned int>/4000 1720 ns 96.3 ns
BM_std_minmax<unsigned int>/4096 1762 ns 97.8 ns
BM_std_minmax<unsigned int>/5500 2364 ns 146 ns
BM_std_minmax<unsigned int>/64000 27874 ns 1905 ns
BM_std_minmax<unsigned int>/65536 28012 ns 1961 ns
BM_std_minmax<unsigned int>/70000 29899 ns 2087 ns
BM_std_minmax<unsigned long long>/1 0.707 ns 1.18 ns
BM_std_minmax<unsigned long long>/2 0.909 ns 1.65 ns
BM_std_minmax<unsigned long long>/3 1.65 ns 2.70 ns
BM_std_minmax<unsigned long long>/4 1.93 ns 2.69 ns
BM_std_minmax<unsigned long long>/5 2.45 ns 3.34 ns
BM_std_minmax<unsigned long long>/6 2.78 ns 3.81 ns
BM_std_minmax<unsigned long long>/7 3.28 ns 4.43 ns
BM_std_minmax<unsigned long long>/8 3.70 ns 4.92 ns
BM_std_minmax<unsigned long long>/9 4.12 ns 5.64 ns
BM_std_minmax<unsigned long long>/10 4.44 ns 6.15 ns
BM_std_minmax<unsigned long long>/11 4.91 ns 6.81 ns
BM_std_minmax<unsigned long long>/12 5.31 ns 7.41 ns
BM_std_minmax<unsigned long long>/13 5.72 ns 7.96 ns
BM_std_minmax<unsigned long long>/14 6.05 ns 8.66 ns
BM_std_minmax<unsigned long long>/15 6.55 ns 9.37 ns
BM_std_minmax<unsigned long long>/16 6.89 ns 7.98 ns
BM_std_minmax<unsigned long long>/17 7.34 ns 8.13 ns
BM_std_minmax<unsigned long long>/18 7.73 ns 8.42 ns
BM_std_minmax<unsigned long long>/19 8.26 ns 8.63 ns
BM_std_minmax<unsigned long long>/20 8.54 ns 8.96 ns
BM_std_minmax<unsigned long long>/21 9.14 ns 9.37 ns
BM_std_minmax<unsigned long long>/22 9.39 ns 9.67 ns
BM_std_minmax<unsigned long long>/23 10.1 ns 10.1 ns
BM_std_minmax<unsigned long long>/24 10.4 ns 10.6 ns
BM_std_minmax<unsigned long long>/25 11.0 ns 11.3 ns
BM_std_minmax<unsigned long long>/26 11.3 ns 12.1 ns
BM_std_minmax<unsigned long long>/27 11.8 ns 14.2 ns
BM_std_minmax<unsigned long long>/28 12.1 ns 15.8 ns
BM_std_minmax<unsigned long long>/29 12.6 ns 17.4 ns
BM_std_minmax<unsigned long long>/30 13.1 ns 18.1 ns
BM_std_minmax<unsigned long long>/31 13.4 ns 18.8 ns
BM_std_minmax<unsigned long long>/32 13.8 ns 10.4 ns
BM_std_minmax<unsigned long long>/64 27.3 ns 15.5 ns
BM_std_minmax<unsigned long long>/512 222 ns 80.6 ns
BM_std_minmax<unsigned long long>/1024 443 ns 156 ns
BM_std_minmax<unsigned long long>/4000 1731 ns 591 ns
BM_std_minmax<unsigned long long>/4096 1752 ns 609 ns
BM_std_minmax<unsigned long long>/5500 2340 ns 819 ns
BM_std_minmax<unsigned long long>/64000 27166 ns 9652 ns
BM_std_minmax<unsigned long long>/65536 27869 ns 9876 ns
BM_std_minmax<unsigned long long>/70000 29920 ns 10680 ns
```

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[libc++][NFC] Make __desugars_to a variable template and rename the header to desugars_to.h (#87337)

This improves compile times and memory usage slightly and removes some
boilerplate.

[libc++] Unify __is_trivial_equality_predicate and __is_trivial_plus_operation into __desugars_to (#68642)

When working on an OpenMP offloading backend for standard parallel
algorithms (https://git

[libc++] Unify __is_trivial_equality_predicate and __is_trivial_plus_operation into __desugars_to (#68642)

When working on an OpenMP offloading backend for standard parallel
algorithms (https://github.com/llvm/llvm-project/pull/66968) we noticed
the need of a generalization of `__is_trivial_plus_operation`. This patch
merges `__is_trivial_equality_predicate` and `__is_trivial_plus_operation`
into `__desugars_to`, and in the future we might extend the latter to support
other binary operations as well.

Co-authored-by: Louis Dionne <ldionne.2@gmail.com>

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[libc++] Refactor __less

This simplifies the usage of `__less` by making the class not depend on the types compared, but instead the `operator()`. We can't remove the template completely because we

[libc++] Refactor __less

This simplifies the usage of `__less` by making the class not depend on the types compared, but instead the `operator()`. We can't remove the template completely because we explicitly instantiate `std::__sort` with `__less<T>`.

Reviewed By: ldionne, #libc

Spies: arichardson, EricWF, libcxx-commits, mgrang

Differential Revision: https://reviews.llvm.org/D145285

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[libc++] Forward to std::memcmp for trivially comparable types in equal

Reviewed By: #libc, ldionne

Spies: ldionne, Mordante, libcxx-commits

Differential Revision: https://reviews.llvm.org/D139554

[libcxx] Fix std::equal not accepting volatile types by refactoring __equal_to

Fixes https://github.com/llvm/llvm-project/issues/59021

Reviewed By: #libc, philnik

Differential Revision: https://re

[libcxx] Fix std::equal not accepting volatile types by refactoring __equal_to

Fixes https://github.com/llvm/llvm-project/issues/59021

Reviewed By: #libc, philnik

Differential Revision: https://reviews.llvm.org/D138268

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[libc++][NFC] Rename the constexpr macros

This was discussed on Discord with the consensus that we should rename the macros.

Reviewed By: ldionne, Mordante, var-const, avogelsgesang, jloser, #libc

[libc++][NFC] Rename the constexpr macros

This was discussed on Discord with the consensus that we should rename the macros.

Reviewed By: ldionne, Mordante, var-const, avogelsgesang, jloser, #libc

Spies: libcxx-commits

Differential Revision: https://reviews.llvm.org/D131498

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[libc++] Revert "Protect users from relying on detail headers" & related changes

This commit reverts 5aaefa51 (and also partly 7f285f48e77 and b6d75682f9,
which were related to the original commit).

[libc++] Revert "Protect users from relying on detail headers" & related changes

This commit reverts 5aaefa51 (and also partly 7f285f48e77 and b6d75682f9,
which were related to the original commit). As landed, 5aaefa51 had
unintended consequences on some downstream bots and didn't have proper
coverage upstream due to a few subtle things. Implementing this is
something we should do in libc++, however we'll first need to address
a few issues listed in https://reviews.llvm.org/D106124#3349710.

Differential Revision: https://reviews.llvm.org/D120683

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[libcxx][modules] protects users from relying on detail headers

libc++ has started splicing standard library headers into much more
fine-grained content for maintainability. It's very likely that ou

[libcxx][modules] protects users from relying on detail headers

libc++ has started splicing standard library headers into much more
fine-grained content for maintainability. It's very likely that outdated
and naive tooling (some of which is outside of LLVM's scope) will
suggest users include things such as <__ranges/access.h> instead of
<ranges>, and Hyrum's law suggests that users will eventually begin to
rely on this without the help of tooling. As such, this commit
intends to protect users from themselves, by making it a hard error for
anyone outside of the standard library to include libc++ detail headers.

Differential Revision: https://reviews.llvm.org/D106124

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[libc++] Normalize all our '#pragma GCC system_header', and regression-test.

Now we'll notice if a header forgets to include this magic phrase.

Differential Revision: https://reviews.llvm.org/D1188

[libc++] Normalize all our '#pragma GCC system_header', and regression-test.

Now we'll notice if a header forgets to include this magic phrase.

Differential Revision: https://reviews.llvm.org/D118800

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[libc++][NFC] Remove useless _LIBCPP_PUSH_MACROS

Only files that actually use min/max are required to do this dance.

Differential Revision: https://reviews.llvm.org/D108778

[libcxx] Move all algorithms into their own headers

This is a fairly mechanical change, it just moves each algorithm into
its own header. This is intended to be a NFC.

This commit re-applies 7ed7d4

[libcxx] Move all algorithms into their own headers

This is a fairly mechanical change, it just moves each algorithm into
its own header. This is intended to be a NFC.

This commit re-applies 7ed7d4ccb899, which was reverted in 692d7166f771
because the Modules build got broken. The modules build has now been
fixed, so we're re-committing this.

Differential Revision: https://reviews.llvm.org/D103583

Attribution note
----------------
I'm only committing this. This commit is a mix of D103583, D103330 and
D104171 authored by:

Co-authored-by: Christopher Di Bella <cjdb@google.com>
Co-authored-by: zoecarver <z.zoelec2@gmail.com>

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[libcxx][gardening] Move all algorithms into their own headers.

This is a fairly mechanical change, it just moves each algorithm into its own header. This is a NFC.

Note: during this change, I burn

[libcxx][gardening] Move all algorithms into their own headers.

This is a fairly mechanical change, it just moves each algorithm into its own header. This is a NFC.

Note: during this change, I burned down all the includes, so this follows "include only and exactly what you use."

Differential Revision: https://reviews.llvm.org/D103583

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