llvm-project.git/libc/src/string/memory_utils/x86_64, branch users/nico/python-1 Unnamed repository; edit this file 'description' to name the repository. [libc] Fix all imports of src/string/memory_utils (#114939) 2025-02-05T17:24:44+00:00 Krishna Pandey 47917477+krishna2803@users.noreply.github.com 2025-02-05T17:24:44+00:00 19c3e2f7de28e10caef40baf94293bb67712401e Fixed imports for all files *within* `libc/src/string/memory_utils`. Note: This doesn't include **all** files that need to be fixed. Fixes #86579 
Fixed imports for all files *within* `libc/src/string/memory_utils`.
Note: This doesn't include **all** files that need to be fixed.

Fixes #86579
 [libc][x86] copy one cache line at a time to prevent the use of `rep;movsb` (#113161) 2024-10-22T08:48:43+00:00 Guillaume Chatelet gchatelet@google.com 2024-10-22T08:48:43+00:00 2f58ac4a22baa27c1e9aad1b3c6d5c687ef03721 When using `-mprefer-vector-width=128` with `-march=sandybridge` copying 3 cache lines in one go (192B) gets converted into `rep;movsb` which translate into a 60% hit in performance. Consecutive calls to `__builtin_memcpy_inline` (implementation behind `builtin::Memcpy::block_offset`) are not coalesced by the compiler and so calling it three times in a row generates the desired assembly. It only differs in the interleaving of the loads and stores and does not affect performance. This is needed to reland https://github.com/llvm/llvm-project/pull/108939. 
When using `-mprefer-vector-width=128` with `-march=sandybridge` copying
3 cache lines in one go (192B) gets converted into `rep;movsb` which
translate into a 60% hit in performance.

Consecutive calls to `__builtin_memcpy_inline` (implementation behind
`builtin::Memcpy::block_offset`) are not coalesced by the compiler and
so calling it three times in a row generates the desired assembly. It
only differs in the interleaving of the loads and stores and does not
affect performance.

This is needed to reland
https://github.com/llvm/llvm-project/pull/108939.
 [libc] Clean up some include in `libc`. (#110980) 2024-10-06T15:08:34+00:00 c8ef c8ef@outlook.com 2024-10-06T15:08:34+00:00 2cc97951400ca2ab79d6bdeccffa6e431882a86e The patch primarily cleans up some incorrect includes. The `LIBC_INLINE` macro is defined in `attributes.h`, not `config.h`. There appears to be no need to change the CMake and Bazel build files. 
The patch primarily cleans up some incorrect includes. The `LIBC_INLINE`
macro is defined in `attributes.h`, not `config.h`. There appears to be
no need to change the CMake and Bazel build files.
 [libc] Implement branchless head-tail comparison for bcmp (#107540) 2024-09-06T09:19:01+00:00 Vitaly Goldshteyn VitalyGoldstein@gmail.com 2024-09-06T09:19:01+00:00 66a03295de26c61a2178bb3a697d355592cb0eb5 Binary size changes: | Bytes (cache lines) | before | after | |---------------------|----------|---------| | sse4 | 419 (7) | 288 (5) | | avx | 430 (7) | 308 (5) | | avx512f | 589 (10) | 390 (7) | Benchmarks for different CPUs using https://github.com/google/fleetbench. - indus-cascadelake ``` name old speed new speed delta BM_LIBC_Bcmp_Fleet_L1 1.96GB/s ± 1% 2.19GB/s ± 0% +11.49% (p=0.000 n=29+24) BM_LIBC_Bcmp_Fleet_L2 1.90GB/s ± 1% 2.14GB/s ± 1% +12.68% (p=0.000 n=29+24) BM_LIBC_Bcmp_Fleet_LLC 513MB/s ± 4% 531MB/s ± 4% +3.53% (p=0.000 n=24+24) BM_LIBC_Bcmp_Fleet_Cold 452MB/s ± 3% 456MB/s ± 4% ~ (p=0.103 n=30+30) BM_LIBC_Bcmp_0_L1 [Bcmp_0] 2.98GB/s ± 1% 3.15GB/s ± 1% +5.59% (p=0.000 n=29+30) BM_LIBC_Bcmp_0_L2 [Bcmp_0] 2.86GB/s ± 1% 3.07GB/s ± 1% +7.21% (p=0.000 n=29+30) BM_LIBC_Bcmp_0_LLC [Bcmp_0] 738MB/s ± 7% 751MB/s ± 3% +1.68% (p=0.000 n=24+25) BM_LIBC_Bcmp_0_Cold [Bcmp_0] 643MB/s ± 3% 642MB/s ± 4% ~ (p=0.522 n=29+30) BM_LIBC_Bcmp_1_L1 [Bcmp_1] 3.08GB/s ± 0% 3.25GB/s ± 0% +5.35% (p=0.000 n=28+30) BM_LIBC_Bcmp_1_L2 [Bcmp_1] 2.97GB/s ± 1% 3.17GB/s ± 1% +6.65% (p=0.000 n=29+30) BM_LIBC_Bcmp_1_LLC [Bcmp_1] 901MB/s ±59% 871MB/s ±36% ~ (p=0.676 n=29+27) BM_LIBC_Bcmp_1_Cold [Bcmp_1] 686MB/s ± 4% 686MB/s ± 3% ~ (p=0.934 n=29+30) BM_LIBC_Bcmp_2_L1 [Bcmp_2] 1.63GB/s ± 0% 1.80GB/s ± 1% +10.19% (p=0.000 n=29+30) BM_LIBC_Bcmp_2_L2 [Bcmp_2] 1.57GB/s ± 1% 1.75GB/s ± 1% +11.46% (p=0.000 n=29+30) BM_LIBC_Bcmp_2_LLC [Bcmp_2] 451MB/s ±61% 427MB/s ±28% ~ (p=0.469 n=29+25) BM_LIBC_Bcmp_2_Cold [Bcmp_2] 353MB/s ± 4% 354MB/s ± 5% ~ (p=0.467 n=30+30) BM_LIBC_Bcmp_3_L1 [Bcmp_3] 1.91GB/s ± 1% 2.10GB/s ± 1% +9.90% (p=0.000 n=29+29) BM_LIBC_Bcmp_3_L2 [Bcmp_3] 1.84GB/s ± 1% 2.03GB/s ± 1% +10.63% (p=0.000 n=29+30) BM_LIBC_Bcmp_3_LLC [Bcmp_3] 491MB/s ±24% 538MB/s ±24% +9.66% (p=0.000 n=24+27) BM_LIBC_Bcmp_3_Cold [Bcmp_3] 417MB/s ± 4% 421MB/s ± 3% ~ (p=0.063 n=30+29) BM_LIBC_Bcmp_4_L1 [Bcmp_4] 761MB/s ± 1% 867MB/s ± 1% +14.02% (p=0.000 n=28+30) BM_LIBC_Bcmp_4_L2 [Bcmp_4] 748MB/s ± 1% 860MB/s ± 1% +15.04% (p=0.000 n=30+30) BM_LIBC_Bcmp_4_LLC [Bcmp_4] 227MB/s ±29% 260MB/s ±64% +14.70% (p=0.000 n=26+27) BM_LIBC_Bcmp_4_Cold [Bcmp_4] 187MB/s ± 3% 191MB/s ± 5% +2.26% (p=0.000 n=30+30) BM_LIBC_Bcmp_5_L1 [Bcmp_5] 1.48GB/s ± 1% 1.71GB/s ± 1% +15.26% (p=0.000 n=29+30) BM_LIBC_Bcmp_5_L2 [Bcmp_5] 1.42GB/s ± 1% 1.67GB/s ± 1% +17.68% (p=0.000 n=29+29) BM_LIBC_Bcmp_5_LLC [Bcmp_5] 412MB/s ±34% 519MB/s ±80% +25.87% (p=0.000 n=27+30) BM_LIBC_Bcmp_5_Cold [Bcmp_5] 336MB/s ± 4% 343MB/s ± 6% +2.05% (p=0.000 n=30+30) BM_LIBC_Bcmp_6_L1 [Bcmp_6] 2.87GB/s ± 0% 3.24GB/s ± 1% +12.88% (p=0.000 n=26+30) BM_LIBC_Bcmp_6_L2 [Bcmp_6] 2.78GB/s ± 1% 3.20GB/s ± 1% +15.15% (p=0.000 n=26+30) BM_LIBC_Bcmp_6_LLC [Bcmp_6] 926MB/s ±43% 1227MB/s ±76% +32.53% (p=0.000 n=27+30) BM_LIBC_Bcmp_6_Cold [Bcmp_6] 716MB/s ± 4% 737MB/s ± 6% +3.02% (p=0.000 n=28+29) BM_LIBC_Bcmp_7_L1 [Bcmp_7] 1.54GB/s ± 1% 1.56GB/s ± 0% +1.40% (p=0.000 n=29+30) BM_LIBC_Bcmp_7_L2 [Bcmp_7] 1.47GB/s ± 1% 1.52GB/s ± 1% +2.97% (p=0.000 n=27+30) BM_LIBC_Bcmp_7_LLC [Bcmp_7] 351MB/s ±23% 436MB/s ±83% +24.04% (p=0.005 n=24+29) BM_LIBC_Bcmp_7_Cold [Bcmp_7] 283MB/s ± 4% 282MB/s ± 4% ~ (p=0.644 n=30+30) BM_LIBC_Bcmp_8_L1 [Bcmp_8] 824MB/s ± 1% 1048MB/s ± 1% +27.18% (p=0.000 n=29+30) BM_LIBC_Bcmp_8_L2 [Bcmp_8] 808MB/s ± 1% 1027MB/s ± 1% +27.12% (p=0.000 n=29+29) BM_LIBC_Bcmp_8_LLC [Bcmp_8] 317MB/s ±79% 332MB/s ±74% ~ (p=0.338 n=30+29) BM_LIBC_Bcmp_8_Cold [Bcmp_8] 207MB/s ± 5% 212MB/s ± 5% +2.27% (p=0.000 n=30+30) ``` - indus-skylake ``` name old speed new speed delta BM_LIBC_Bcmp_Fleet_L1 2.06GB/s ± 2% 2.25GB/s ± 3% +9.66% (p=0.000 n=27+24) BM_LIBC_Bcmp_Fleet_L2 1.96GB/s ± 2% 2.17GB/s ± 2% +10.61% (p=0.000 n=30+24) BM_LIBC_Bcmp_Fleet_LLC 1.18GB/s ± 6% 1.32GB/s ± 5% +12.27% (p=0.000 n=28+28) BM_LIBC_Bcmp_Fleet_Cold 456MB/s ± 2% 466MB/s ± 2% +2.22% (p=0.000 n=28+28) BM_LIBC_Bcmp_0_L1 [Bcmp_0] 3.08GB/s ± 2% 3.20GB/s ± 1% +3.72% (p=0.000 n=28+22) BM_LIBC_Bcmp_0_L2 [Bcmp_0] 2.92GB/s ± 1% 3.05GB/s ± 2% +4.49% (p=0.000 n=23+23) BM_LIBC_Bcmp_0_LLC [Bcmp_0] 1.83GB/s ± 8% 1.94GB/s ± 4% +6.24% (p=0.000 n=25+27) BM_LIBC_Bcmp_0_Cold [Bcmp_0] 654MB/s ± 2% 659MB/s ± 2% +0.76% (p=0.012 n=30+29) BM_LIBC_Bcmp_1_L1 [Bcmp_1] 3.19GB/s ± 2% 3.34GB/s ± 2% +4.41% (p=0.000 n=26+23) BM_LIBC_Bcmp_1_L2 [Bcmp_1] 3.05GB/s ± 2% 3.21GB/s ± 2% +5.32% (p=0.000 n=28+25) BM_LIBC_Bcmp_1_LLC [Bcmp_1] 1.95GB/s ± 4% 2.03GB/s ±10% +3.61% (p=0.000 n=27+30) BM_LIBC_Bcmp_1_Cold [Bcmp_1] 700MB/s ± 2% 702MB/s ± 2% ~ (p=0.150 n=30+30) BM_LIBC_Bcmp_2_L1 [Bcmp_2] 1.69GB/s ± 2% 1.85GB/s ± 1% +9.31% (p=0.000 n=30+26) BM_LIBC_Bcmp_2_L2 [Bcmp_2] 1.60GB/s ± 2% 1.78GB/s ± 2% +10.90% (p=0.000 n=26+27) BM_LIBC_Bcmp_2_LLC [Bcmp_2] 1.01GB/s ± 5% 1.12GB/s ± 5% +11.40% (p=0.000 n=27+28) BM_LIBC_Bcmp_2_Cold [Bcmp_2] 355MB/s ± 3% 360MB/s ± 3% +1.46% (p=0.000 n=30+30) BM_LIBC_Bcmp_3_L1 [Bcmp_3] 1.98GB/s ± 2% 2.15GB/s ± 2% +8.89% (p=0.000 n=29+27) BM_LIBC_Bcmp_3_L2 [Bcmp_3] 1.87GB/s ± 3% 2.05GB/s ± 2% +10.06% (p=0.000 n=30+26) BM_LIBC_Bcmp_3_LLC [Bcmp_3] 1.19GB/s ± 4% 1.31GB/s ± 6% +9.82% (p=0.000 n=27+29) BM_LIBC_Bcmp_3_Cold [Bcmp_3] 424MB/s ± 3% 431MB/s ± 3% +1.58% (p=0.000 n=28+30) BM_LIBC_Bcmp_4_L1 [Bcmp_4] 849MB/s ± 2% 949MB/s ± 2% +11.84% (p=0.000 n=27+28) BM_LIBC_Bcmp_4_L2 [Bcmp_4] 815MB/s ± 3% 913MB/s ± 3% +12.06% (p=0.000 n=29+30) BM_LIBC_Bcmp_4_LLC [Bcmp_4] 512MB/s ± 9% 571MB/s ± 7% +11.40% (p=0.000 n=30+30) BM_LIBC_Bcmp_4_Cold [Bcmp_4] 187MB/s ± 3% 192MB/s ± 2% +2.56% (p=0.000 n=30+28) BM_LIBC_Bcmp_5_L1 [Bcmp_5] 1.55GB/s ± 2% 1.77GB/s ± 3% +13.93% (p=0.000 n=30+28) BM_LIBC_Bcmp_5_L2 [Bcmp_5] 1.47GB/s ± 2% 1.70GB/s ± 2% +15.96% (p=0.000 n=27+26) BM_LIBC_Bcmp_5_LLC [Bcmp_5] 939MB/s ± 5% 1084MB/s ± 4% +15.36% (p=0.000 n=28+27) BM_LIBC_Bcmp_5_Cold [Bcmp_5] 340MB/s ± 2% 347MB/s ± 3% +1.93% (p=0.000 n=30+30) BM_LIBC_Bcmp_6_L1 [Bcmp_6] 3.06GB/s ± 3% 3.40GB/s ± 2% +11.13% (p=0.000 n=30+28) BM_LIBC_Bcmp_6_L2 [Bcmp_6] 2.89GB/s ± 3% 3.24GB/s ± 2% +12.20% (p=0.000 n=29+26) BM_LIBC_Bcmp_6_LLC [Bcmp_6] 1.93GB/s ± 4% 2.09GB/s ±11% +8.16% (p=0.000 n=26+30) BM_LIBC_Bcmp_6_Cold [Bcmp_6] 746MB/s ± 2% 762MB/s ± 2% +2.11% (p=0.000 n=30+28) BM_LIBC_Bcmp_7_L1 [Bcmp_7] 1.59GB/s ± 2% 1.62GB/s ± 2% +1.72% (p=0.000 n=25+27) BM_LIBC_Bcmp_7_L2 [Bcmp_7] 1.49GB/s ± 2% 1.53GB/s ± 2% +2.62% (p=0.000 n=27+29) BM_LIBC_Bcmp_7_LLC [Bcmp_7] 852MB/s ±10% 909MB/s ± 6% +6.71% (p=0.000 n=30+29) BM_LIBC_Bcmp_7_Cold [Bcmp_7] 283MB/s ± 3% 283MB/s ± 2% ~ (p=0.617 n=30+27) BM_LIBC_Bcmp_8_L1 [Bcmp_8] 891MB/s ± 2% 1083MB/s ± 2% +21.64% (p=0.000 n=27+24) BM_LIBC_Bcmp_8_L2 [Bcmp_8] 855MB/s ± 2% 1045MB/s ± 1% +22.31% (p=0.000 n=25+23) BM_LIBC_Bcmp_8_LLC [Bcmp_8] 568MB/s ± 7% 659MB/s ± 8% +16.04% (p=0.000 n=29+30) BM_LIBC_Bcmp_8_Cold [Bcmp_8] 207MB/s ± 2% 212MB/s ± 2% +2.31% (p=0.000 n=30+27) ``` - arcadia-rome ``` name old speed new speed delta BM_LIBC_Bcmp_Fleet_L1 2.16GB/s ± 2% 2.27GB/s ± 2% +5.13% (p=0.000 n=26+30) BM_LIBC_Bcmp_Fleet_L2 2.15GB/s ± 2% 2.25GB/s ± 2% +4.64% (p=0.000 n=27+30) BM_LIBC_Bcmp_Fleet_LLC 1.73GB/s ± 3% 1.81GB/s ± 3% +4.66% (p=0.000 n=25+28) BM_LIBC_Bcmp_Fleet_Cold 494MB/s ± 1% 496MB/s ± 2% +0.45% (p=0.023 n=22+24) BM_LIBC_Bcmp_0_L1 [Bcmp_0] 3.30GB/s ± 1% 3.24GB/s ± 2% -1.70% (p=0.000 n=27+30) BM_LIBC_Bcmp_0_L2 [Bcmp_0] 3.23GB/s ± 2% 3.19GB/s ± 2% -1.28% (p=0.000 n=28+28) BM_LIBC_Bcmp_0_LLC [Bcmp_0] 2.59GB/s ± 3% 2.58GB/s ± 2% -0.65% (p=0.010 n=26+26) BM_LIBC_Bcmp_0_Cold [Bcmp_0] 720MB/s ± 1% 707MB/s ± 3% -1.75% (p=0.000 n=22+25) BM_LIBC_Bcmp_1_L1 [Bcmp_1] 3.37GB/s ± 1% 3.36GB/s ± 2% ~ (p=0.102 n=28+29) BM_LIBC_Bcmp_1_L2 [Bcmp_1] 3.32GB/s ± 2% 3.30GB/s ± 2% -0.51% (p=0.038 n=28+29) BM_LIBC_Bcmp_1_LLC [Bcmp_1] 2.67GB/s ± 4% 2.70GB/s ± 4% +0.96% (p=0.009 n=28+27) BM_LIBC_Bcmp_1_Cold [Bcmp_1] 755MB/s ± 1% 751MB/s ± 2% -0.57% (p=0.000 n=22+25) BM_LIBC_Bcmp_2_L1 [Bcmp_2] 1.79GB/s ± 1% 1.86GB/s ± 2% +3.92% (p=0.000 n=27+29) BM_LIBC_Bcmp_2_L2 [Bcmp_2] 1.77GB/s ± 2% 1.82GB/s ± 2% +2.99% (p=0.000 n=28+29) BM_LIBC_Bcmp_2_LLC [Bcmp_2] 1.41GB/s ± 4% 1.47GB/s ± 3% +3.97% (p=0.000 n=28+28) BM_LIBC_Bcmp_2_Cold [Bcmp_2] 386MB/s ± 1% 389MB/s ± 1% +0.60% (p=0.000 n=21+23) BM_LIBC_Bcmp_3_L1 [Bcmp_3] 2.07GB/s ± 2% 2.17GB/s ± 2% +4.87% (p=0.000 n=29+30) BM_LIBC_Bcmp_3_L2 [Bcmp_3] 2.07GB/s ± 2% 2.13GB/s ± 2% +3.02% (p=0.000 n=28+30) BM_LIBC_Bcmp_3_LLC [Bcmp_3] 1.66GB/s ± 2% 1.73GB/s ± 2% +4.08% (p=0.000 n=29+26) BM_LIBC_Bcmp_3_Cold [Bcmp_3] 466MB/s ± 2% 469MB/s ± 3% +0.66% (p=0.001 n=22+25) BM_LIBC_Bcmp_4_L1 [Bcmp_4] 861MB/s ± 1% 964MB/s ± 2% +11.98% (p=0.000 n=29+29) BM_LIBC_Bcmp_4_L2 [Bcmp_4] 853MB/s ± 2% 935MB/s ± 2% +9.54% (p=0.000 n=28+29) BM_LIBC_Bcmp_4_LLC [Bcmp_4] 707MB/s ± 3% 743MB/s ± 4% +5.08% (p=0.000 n=29+29) BM_LIBC_Bcmp_4_Cold [Bcmp_4] 199MB/s ± 3% 199MB/s ± 2% ~ (p=0.107 n=29+25) BM_LIBC_Bcmp_5_L1 [Bcmp_5] 1.65GB/s ± 1% 1.75GB/s ± 2% +6.15% (p=0.000 n=29+29) BM_LIBC_Bcmp_5_L2 [Bcmp_5] 1.64GB/s ± 3% 1.73GB/s ± 2% +5.37% (p=0.000 n=29+29) BM_LIBC_Bcmp_5_LLC [Bcmp_5] 1.32GB/s ± 2% 1.40GB/s ± 2% +6.21% (p=0.000 n=28+27) BM_LIBC_Bcmp_5_Cold [Bcmp_5] 370MB/s ± 3% 371MB/s ± 2% +0.16% (p=0.008 n=29+25) BM_LIBC_Bcmp_6_L1 [Bcmp_6] 3.25GB/s ± 2% 3.47GB/s ± 2% +6.74% (p=0.000 n=28+29) BM_LIBC_Bcmp_6_L2 [Bcmp_6] 3.26GB/s ± 1% 3.44GB/s ± 1% +5.43% (p=0.000 n=28+29) BM_LIBC_Bcmp_6_LLC [Bcmp_6] 2.66GB/s ± 2% 2.79GB/s ± 3% +4.90% (p=0.000 n=27+29) BM_LIBC_Bcmp_6_Cold [Bcmp_6] 812MB/s ± 3% 799MB/s ± 2% -1.57% (p=0.000 n=29+25) BM_LIBC_Bcmp_7_L1 [Bcmp_7] 1.71GB/s ± 2% 1.66GB/s ± 2% -3.14% (p=0.000 n=29+29) BM_LIBC_Bcmp_7_L2 [Bcmp_7] 1.63GB/s ± 2% 1.59GB/s ± 2% -2.50% (p=0.000 n=29+28) BM_LIBC_Bcmp_7_LLC [Bcmp_7] 1.25GB/s ± 4% 1.25GB/s ± 2% ~ (p=0.530 n=28+26) BM_LIBC_Bcmp_7_Cold [Bcmp_7] 311MB/s ± 3% 308MB/s ± 1% ~ (p=0.127 n=29+24) BM_LIBC_Bcmp_8_L1 [Bcmp_8] 869MB/s ± 2% 1098MB/s ± 2% +26.28% (p=0.000 n=27+29) BM_LIBC_Bcmp_8_L2 [Bcmp_8] 873MB/s ± 2% 1075MB/s ± 1% +23.06% (p=0.000 n=27+29) BM_LIBC_Bcmp_8_LLC [Bcmp_8] 743MB/s ± 4% 859MB/s ± 4% +15.58% (p=0.000 n=27+27) BM_LIBC_Bcmp_8_Cold [Bcmp_8] 221MB/s ± 4% 221MB/s ± 3% +0.14% (p=0.034 n=29+25) ``` - ixion-haswell ``` name old speed new speed delta BM_LIBC_Bcmp_Fleet_L1 2.27GB/s ± 5% 2.41GB/s ± 6% +6.10% (p=0.000 n=29+28) BM_LIBC_Bcmp_Fleet_L2 2.14GB/s ± 6% 2.33GB/s ± 5% +9.21% (p=0.000 n=29+30) BM_LIBC_Bcmp_Fleet_LLC 1.30GB/s ± 9% 1.43GB/s ± 8% +9.85% (p=0.000 n=30+30) BM_LIBC_Bcmp_Fleet_Cold 475MB/s ± 6% 475MB/s ± 5% ~ (p=0.839 n=30+29) BM_LIBC_Bcmp_0_L1 [Bcmp_0] 3.38GB/s ± 7% 3.46GB/s ± 6% +2.35% (p=0.009 n=30+29) BM_LIBC_Bcmp_0_L2 [Bcmp_0] 3.20GB/s ± 5% 3.32GB/s ± 6% +3.52% (p=0.000 n=28+30) BM_LIBC_Bcmp_0_LLC [Bcmp_0] 1.88GB/s ± 9% 2.00GB/s ± 6% +6.63% (p=0.000 n=30+28) BM_LIBC_Bcmp_0_Cold [Bcmp_0] 664MB/s ± 6% 655MB/s ± 6% -1.32% (p=0.025 n=30+30) BM_LIBC_Bcmp_1_L1 [Bcmp_1] 3.50GB/s ± 8% 3.61GB/s ±10% +3.09% (p=0.001 n=29+30) BM_LIBC_Bcmp_1_L2 [Bcmp_1] 3.32GB/s ± 7% 3.48GB/s ± 8% +4.89% (p=0.000 n=29+30) BM_LIBC_Bcmp_1_LLC [Bcmp_1] 2.02GB/s ± 7% 2.14GB/s ± 9% +5.82% (p=0.000 n=28+29) BM_LIBC_Bcmp_1_Cold [Bcmp_1] 716MB/s ± 6% 709MB/s ± 5% -0.97% (p=0.040 n=30+28) BM_LIBC_Bcmp_2_L1 [Bcmp_2] 1.83GB/s ± 7% 1.97GB/s ± 8% +7.90% (p=0.000 n=30+30) BM_LIBC_Bcmp_2_L2 [Bcmp_2] 1.74GB/s ± 6% 1.92GB/s ± 6% +10.29% (p=0.000 n=30+29) BM_LIBC_Bcmp_2_LLC [Bcmp_2] 1.05GB/s ± 9% 1.15GB/s ± 9% +9.73% (p=0.000 n=30+30) BM_LIBC_Bcmp_2_Cold [Bcmp_2] 379MB/s ± 6% 372MB/s ± 6% -1.74% (p=0.012 n=30+30) BM_LIBC_Bcmp_3_L1 [Bcmp_3] 2.17GB/s ± 5% 2.29GB/s ± 6% +5.61% (p=0.000 n=29+30) BM_LIBC_Bcmp_3_L2 [Bcmp_3] 2.02GB/s ± 6% 2.20GB/s ± 6% +8.75% (p=0.000 n=29+30) BM_LIBC_Bcmp_3_LLC [Bcmp_3] 1.22GB/s ± 8% 1.34GB/s ± 9% +9.19% (p=0.000 n=30+30) BM_LIBC_Bcmp_3_Cold [Bcmp_3] 447MB/s ± 3% 441MB/s ± 7% -1.40% (p=0.033 n=30+30) BM_LIBC_Bcmp_4_L1 [Bcmp_4] 902MB/s ± 6% 995MB/s ±10% +10.37% (p=0.000 n=30+30) BM_LIBC_Bcmp_4_L2 [Bcmp_4] 863MB/s ± 5% 945MB/s ±11% +9.50% (p=0.000 n=29+30) BM_LIBC_Bcmp_4_LLC [Bcmp_4] 528MB/s ±11% 559MB/s ±12% +5.75% (p=0.000 n=30+30) BM_LIBC_Bcmp_4_Cold [Bcmp_4] 183MB/s ± 4% 181MB/s ± 7% ~ (p=0.088 n=28+30) BM_LIBC_Bcmp_5_L1 [Bcmp_5] 1.70GB/s ± 6% 1.87GB/s ± 8% +10.14% (p=0.000 n=29+29) BM_LIBC_Bcmp_5_L2 [Bcmp_5] 1.60GB/s ± 5% 1.80GB/s ± 9% +12.61% (p=0.000 n=29+30) BM_LIBC_Bcmp_5_LLC [Bcmp_5] 994MB/s ±13% 1094MB/s ± 8% +10.10% (p=0.000 n=29+30) BM_LIBC_Bcmp_5_Cold [Bcmp_5] 362MB/s ± 6% 358MB/s ± 7% ~ (p=0.123 n=30+30) BM_LIBC_Bcmp_6_L1 [Bcmp_6] 3.31GB/s ± 5% 3.67GB/s ± 6% +10.90% (p=0.000 n=28+30) BM_LIBC_Bcmp_6_L2 [Bcmp_6] 3.11GB/s ± 5% 3.53GB/s ± 5% +13.59% (p=0.000 n=30+30) BM_LIBC_Bcmp_6_LLC [Bcmp_6] 1.98GB/s ± 9% 2.18GB/s ± 8% +10.34% (p=0.000 n=30+30) BM_LIBC_Bcmp_6_Cold [Bcmp_6] 754MB/s ± 5% 752MB/s ± 5% ~ (p=0.592 n=30+30) BM_LIBC_Bcmp_7_L1 [Bcmp_7] 1.72GB/s ± 5% 1.72GB/s ± 6% ~ (p=0.549 n=29+29) BM_LIBC_Bcmp_7_L2 [Bcmp_7] 1.61GB/s ± 7% 1.63GB/s ± 8% ~ (p=0.191 n=30+29) BM_LIBC_Bcmp_7_LLC [Bcmp_7] 913MB/s ± 8% 905MB/s ± 9% ~ (p=0.423 n=30+30) BM_LIBC_Bcmp_7_Cold [Bcmp_7] 304MB/s ± 6% 287MB/s ± 4% -5.57% (p=0.000 n=30+30) BM_LIBC_Bcmp_8_L1 [Bcmp_8] 961MB/s ± 5% 1124MB/s ± 6% +16.94% (p=0.000 n=30+30) BM_LIBC_Bcmp_8_L2 [Bcmp_8] 915MB/s ± 8% 1100MB/s ± 7% +20.16% (p=0.000 n=30+30) BM_LIBC_Bcmp_8_LLC [Bcmp_8] 593MB/s ± 8% 669MB/s ± 8% +12.92% (p=0.000 n=30+30) BM_LIBC_Bcmp_8_Cold [Bcmp_8] 220MB/s ± 4% 220MB/s ± 6% ~ (p=0.572 n=30+30) ``` Co-authored-by: goldvitaly@google.com <%username%@google.com> 
Binary size changes:

| Bytes (cache lines) | before   | after   |
|---------------------|----------|---------|
| sse4                | 419 (7)  | 288 (5) |
| avx                 | 430 (7)  | 308 (5) |
| avx512f             | 589 (10) | 390 (7) |

Benchmarks for different CPUs using
https://github.com/google/fleetbench.

 - indus-cascadelake

```
name                                                       old speed            new speed            delta
BM_LIBC_Bcmp_Fleet_L1                                      1.96GB/s ± 1%        2.19GB/s ± 0%  +11.49%  (p=0.000 n=29+24)
BM_LIBC_Bcmp_Fleet_L2                                      1.90GB/s ± 1%        2.14GB/s ± 1%  +12.68%  (p=0.000 n=29+24)
BM_LIBC_Bcmp_Fleet_LLC                                      513MB/s ± 4%         531MB/s ± 4%   +3.53%  (p=0.000 n=24+24)
BM_LIBC_Bcmp_Fleet_Cold                                     452MB/s ± 3%         456MB/s ± 4%     ~     (p=0.103 n=30+30)
BM_LIBC_Bcmp_0_L1                                [Bcmp_0]  2.98GB/s ± 1%        3.15GB/s ± 1%   +5.59%  (p=0.000 n=29+30)
BM_LIBC_Bcmp_0_L2                                [Bcmp_0]  2.86GB/s ± 1%        3.07GB/s ± 1%   +7.21%  (p=0.000 n=29+30)
BM_LIBC_Bcmp_0_LLC                               [Bcmp_0]   738MB/s ± 7%         751MB/s ± 3%   +1.68%  (p=0.000 n=24+25)
BM_LIBC_Bcmp_0_Cold                              [Bcmp_0]   643MB/s ± 3%         642MB/s ± 4%     ~     (p=0.522 n=29+30)
BM_LIBC_Bcmp_1_L1                                [Bcmp_1]  3.08GB/s ± 0%        3.25GB/s ± 0%   +5.35%  (p=0.000 n=28+30)
BM_LIBC_Bcmp_1_L2                                [Bcmp_1]  2.97GB/s ± 1%        3.17GB/s ± 1%   +6.65%  (p=0.000 n=29+30)
BM_LIBC_Bcmp_1_LLC                               [Bcmp_1]   901MB/s ±59%         871MB/s ±36%     ~     (p=0.676 n=29+27)
BM_LIBC_Bcmp_1_Cold                              [Bcmp_1]   686MB/s ± 4%         686MB/s ± 3%     ~     (p=0.934 n=29+30)
BM_LIBC_Bcmp_2_L1                                [Bcmp_2]  1.63GB/s ± 0%        1.80GB/s ± 1%  +10.19%  (p=0.000 n=29+30)
BM_LIBC_Bcmp_2_L2                                [Bcmp_2]  1.57GB/s ± 1%        1.75GB/s ± 1%  +11.46%  (p=0.000 n=29+30)
BM_LIBC_Bcmp_2_LLC                               [Bcmp_2]   451MB/s ±61%         427MB/s ±28%     ~     (p=0.469 n=29+25)
BM_LIBC_Bcmp_2_Cold                              [Bcmp_2]   353MB/s ± 4%         354MB/s ± 5%     ~     (p=0.467 n=30+30)
BM_LIBC_Bcmp_3_L1                                [Bcmp_3]  1.91GB/s ± 1%        2.10GB/s ± 1%   +9.90%  (p=0.000 n=29+29)
BM_LIBC_Bcmp_3_L2                                [Bcmp_3]  1.84GB/s ± 1%        2.03GB/s ± 1%  +10.63%  (p=0.000 n=29+30)
BM_LIBC_Bcmp_3_LLC                               [Bcmp_3]   491MB/s ±24%         538MB/s ±24%   +9.66%  (p=0.000 n=24+27)
BM_LIBC_Bcmp_3_Cold                              [Bcmp_3]   417MB/s ± 4%         421MB/s ± 3%     ~     (p=0.063 n=30+29)
BM_LIBC_Bcmp_4_L1                                [Bcmp_4]   761MB/s ± 1%         867MB/s ± 1%  +14.02%  (p=0.000 n=28+30)
BM_LIBC_Bcmp_4_L2                                [Bcmp_4]   748MB/s ± 1%         860MB/s ± 1%  +15.04%  (p=0.000 n=30+30)
BM_LIBC_Bcmp_4_LLC                               [Bcmp_4]   227MB/s ±29%         260MB/s ±64%  +14.70%  (p=0.000 n=26+27)
BM_LIBC_Bcmp_4_Cold                              [Bcmp_4]   187MB/s ± 3%         191MB/s ± 5%   +2.26%  (p=0.000 n=30+30)
BM_LIBC_Bcmp_5_L1                                [Bcmp_5]  1.48GB/s ± 1%        1.71GB/s ± 1%  +15.26%  (p=0.000 n=29+30)
BM_LIBC_Bcmp_5_L2                                [Bcmp_5]  1.42GB/s ± 1%        1.67GB/s ± 1%  +17.68%  (p=0.000 n=29+29)
BM_LIBC_Bcmp_5_LLC                               [Bcmp_5]   412MB/s ±34%         519MB/s ±80%  +25.87%  (p=0.000 n=27+30)
BM_LIBC_Bcmp_5_Cold                              [Bcmp_5]   336MB/s ± 4%         343MB/s ± 6%   +2.05%  (p=0.000 n=30+30)
BM_LIBC_Bcmp_6_L1                                [Bcmp_6]  2.87GB/s ± 0%        3.24GB/s ± 1%  +12.88%  (p=0.000 n=26+30)
BM_LIBC_Bcmp_6_L2                                [Bcmp_6]  2.78GB/s ± 1%        3.20GB/s ± 1%  +15.15%  (p=0.000 n=26+30)
BM_LIBC_Bcmp_6_LLC                               [Bcmp_6]   926MB/s ±43%        1227MB/s ±76%  +32.53%  (p=0.000 n=27+30)
BM_LIBC_Bcmp_6_Cold                              [Bcmp_6]   716MB/s ± 4%         737MB/s ± 6%   +3.02%  (p=0.000 n=28+29)
BM_LIBC_Bcmp_7_L1                                [Bcmp_7]  1.54GB/s ± 1%        1.56GB/s ± 0%   +1.40%  (p=0.000 n=29+30)
BM_LIBC_Bcmp_7_L2                                [Bcmp_7]  1.47GB/s ± 1%        1.52GB/s ± 1%   +2.97%  (p=0.000 n=27+30)
BM_LIBC_Bcmp_7_LLC                               [Bcmp_7]   351MB/s ±23%         436MB/s ±83%  +24.04%  (p=0.005 n=24+29)
BM_LIBC_Bcmp_7_Cold                              [Bcmp_7]   283MB/s ± 4%         282MB/s ± 4%     ~     (p=0.644 n=30+30)
BM_LIBC_Bcmp_8_L1                                [Bcmp_8]   824MB/s ± 1%        1048MB/s ± 1%  +27.18%  (p=0.000 n=29+30)
BM_LIBC_Bcmp_8_L2                                [Bcmp_8]   808MB/s ± 1%        1027MB/s ± 1%  +27.12%  (p=0.000 n=29+29)
BM_LIBC_Bcmp_8_LLC                               [Bcmp_8]   317MB/s ±79%         332MB/s ±74%     ~     (p=0.338 n=30+29)
BM_LIBC_Bcmp_8_Cold                              [Bcmp_8]   207MB/s ± 5%         212MB/s ± 5%   +2.27%  (p=0.000 n=30+30)
```

 - indus-skylake

```
name                                                       old speed            new speed            delta
BM_LIBC_Bcmp_Fleet_L1                                      2.06GB/s ± 2%        2.25GB/s ± 3%   +9.66%  (p=0.000 n=27+24)
BM_LIBC_Bcmp_Fleet_L2                                      1.96GB/s ± 2%        2.17GB/s ± 2%  +10.61%  (p=0.000 n=30+24)
BM_LIBC_Bcmp_Fleet_LLC                                     1.18GB/s ± 6%        1.32GB/s ± 5%  +12.27%  (p=0.000 n=28+28)
BM_LIBC_Bcmp_Fleet_Cold                                     456MB/s ± 2%         466MB/s ± 2%   +2.22%  (p=0.000 n=28+28)
BM_LIBC_Bcmp_0_L1                                [Bcmp_0]  3.08GB/s ± 2%        3.20GB/s ± 1%   +3.72%  (p=0.000 n=28+22)
BM_LIBC_Bcmp_0_L2                                [Bcmp_0]  2.92GB/s ± 1%        3.05GB/s ± 2%   +4.49%  (p=0.000 n=23+23)
BM_LIBC_Bcmp_0_LLC                               [Bcmp_0]  1.83GB/s ± 8%        1.94GB/s ± 4%   +6.24%  (p=0.000 n=25+27)
BM_LIBC_Bcmp_0_Cold                              [Bcmp_0]   654MB/s ± 2%         659MB/s ± 2%   +0.76%  (p=0.012 n=30+29)
BM_LIBC_Bcmp_1_L1                                [Bcmp_1]  3.19GB/s ± 2%        3.34GB/s ± 2%   +4.41%  (p=0.000 n=26+23)
BM_LIBC_Bcmp_1_L2                                [Bcmp_1]  3.05GB/s ± 2%        3.21GB/s ± 2%   +5.32%  (p=0.000 n=28+25)
BM_LIBC_Bcmp_1_LLC                               [Bcmp_1]  1.95GB/s ± 4%        2.03GB/s ±10%   +3.61%  (p=0.000 n=27+30)
BM_LIBC_Bcmp_1_Cold                              [Bcmp_1]   700MB/s ± 2%         702MB/s ± 2%     ~     (p=0.150 n=30+30)
BM_LIBC_Bcmp_2_L1                                [Bcmp_2]  1.69GB/s ± 2%        1.85GB/s ± 1%   +9.31%  (p=0.000 n=30+26)
BM_LIBC_Bcmp_2_L2                                [Bcmp_2]  1.60GB/s ± 2%        1.78GB/s ± 2%  +10.90%  (p=0.000 n=26+27)
BM_LIBC_Bcmp_2_LLC                               [Bcmp_2]  1.01GB/s ± 5%        1.12GB/s ± 5%  +11.40%  (p=0.000 n=27+28)
BM_LIBC_Bcmp_2_Cold                              [Bcmp_2]   355MB/s ± 3%         360MB/s ± 3%   +1.46%  (p=0.000 n=30+30)
BM_LIBC_Bcmp_3_L1                                [Bcmp_3]  1.98GB/s ± 2%        2.15GB/s ± 2%   +8.89%  (p=0.000 n=29+27)
BM_LIBC_Bcmp_3_L2                                [Bcmp_3]  1.87GB/s ± 3%        2.05GB/s ± 2%  +10.06%  (p=0.000 n=30+26)
BM_LIBC_Bcmp_3_LLC                               [Bcmp_3]  1.19GB/s ± 4%        1.31GB/s ± 6%   +9.82%  (p=0.000 n=27+29)
BM_LIBC_Bcmp_3_Cold                              [Bcmp_3]   424MB/s ± 3%         431MB/s ± 3%   +1.58%  (p=0.000 n=28+30)
BM_LIBC_Bcmp_4_L1                                [Bcmp_4]   849MB/s ± 2%         949MB/s ± 2%  +11.84%  (p=0.000 n=27+28)
BM_LIBC_Bcmp_4_L2                                [Bcmp_4]   815MB/s ± 3%         913MB/s ± 3%  +12.06%  (p=0.000 n=29+30)
BM_LIBC_Bcmp_4_LLC                               [Bcmp_4]   512MB/s ± 9%         571MB/s ± 7%  +11.40%  (p=0.000 n=30+30)
BM_LIBC_Bcmp_4_Cold                              [Bcmp_4]   187MB/s ± 3%         192MB/s ± 2%   +2.56%  (p=0.000 n=30+28)
BM_LIBC_Bcmp_5_L1                                [Bcmp_5]  1.55GB/s ± 2%        1.77GB/s ± 3%  +13.93%  (p=0.000 n=30+28)
BM_LIBC_Bcmp_5_L2                                [Bcmp_5]  1.47GB/s ± 2%        1.70GB/s ± 2%  +15.96%  (p=0.000 n=27+26)
BM_LIBC_Bcmp_5_LLC                               [Bcmp_5]   939MB/s ± 5%        1084MB/s ± 4%  +15.36%  (p=0.000 n=28+27)
BM_LIBC_Bcmp_5_Cold                              [Bcmp_5]   340MB/s ± 2%         347MB/s ± 3%   +1.93%  (p=0.000 n=30+30)
BM_LIBC_Bcmp_6_L1                                [Bcmp_6]  3.06GB/s ± 3%        3.40GB/s ± 2%  +11.13%  (p=0.000 n=30+28)
BM_LIBC_Bcmp_6_L2                                [Bcmp_6]  2.89GB/s ± 3%        3.24GB/s ± 2%  +12.20%  (p=0.000 n=29+26)
BM_LIBC_Bcmp_6_LLC                               [Bcmp_6]  1.93GB/s ± 4%        2.09GB/s ±11%   +8.16%  (p=0.000 n=26+30)
BM_LIBC_Bcmp_6_Cold                              [Bcmp_6]   746MB/s ± 2%         762MB/s ± 2%   +2.11%  (p=0.000 n=30+28)
BM_LIBC_Bcmp_7_L1                                [Bcmp_7]  1.59GB/s ± 2%        1.62GB/s ± 2%   +1.72%  (p=0.000 n=25+27)
BM_LIBC_Bcmp_7_L2                                [Bcmp_7]  1.49GB/s ± 2%        1.53GB/s ± 2%   +2.62%  (p=0.000 n=27+29)
BM_LIBC_Bcmp_7_LLC                               [Bcmp_7]   852MB/s ±10%         909MB/s ± 6%   +6.71%  (p=0.000 n=30+29)
BM_LIBC_Bcmp_7_Cold                              [Bcmp_7]   283MB/s ± 3%         283MB/s ± 2%     ~     (p=0.617 n=30+27)
BM_LIBC_Bcmp_8_L1                                [Bcmp_8]   891MB/s ± 2%        1083MB/s ± 2%  +21.64%  (p=0.000 n=27+24)
BM_LIBC_Bcmp_8_L2                                [Bcmp_8]   855MB/s ± 2%        1045MB/s ± 1%  +22.31%  (p=0.000 n=25+23)
BM_LIBC_Bcmp_8_LLC                               [Bcmp_8]   568MB/s ± 7%         659MB/s ± 8%  +16.04%  (p=0.000 n=29+30)
BM_LIBC_Bcmp_8_Cold                              [Bcmp_8]   207MB/s ± 2%         212MB/s ± 2%   +2.31%  (p=0.000 n=30+27)
```

 - arcadia-rome

```
name                                                       old speed            new speed            delta
BM_LIBC_Bcmp_Fleet_L1                                      2.16GB/s ± 2%        2.27GB/s ± 2%   +5.13%  (p=0.000 n=26+30)
BM_LIBC_Bcmp_Fleet_L2                                      2.15GB/s ± 2%        2.25GB/s ± 2%   +4.64%  (p=0.000 n=27+30)
BM_LIBC_Bcmp_Fleet_LLC                                     1.73GB/s ± 3%        1.81GB/s ± 3%   +4.66%  (p=0.000 n=25+28)
BM_LIBC_Bcmp_Fleet_Cold                                     494MB/s ± 1%         496MB/s ± 2%   +0.45%  (p=0.023 n=22+24)
BM_LIBC_Bcmp_0_L1                                [Bcmp_0]  3.30GB/s ± 1%        3.24GB/s ± 2%   -1.70%  (p=0.000 n=27+30)
BM_LIBC_Bcmp_0_L2                                [Bcmp_0]  3.23GB/s ± 2%        3.19GB/s ± 2%   -1.28%  (p=0.000 n=28+28)
BM_LIBC_Bcmp_0_LLC                               [Bcmp_0]  2.59GB/s ± 3%        2.58GB/s ± 2%   -0.65%  (p=0.010 n=26+26)
BM_LIBC_Bcmp_0_Cold                              [Bcmp_0]   720MB/s ± 1%         707MB/s ± 3%   -1.75%  (p=0.000 n=22+25)
BM_LIBC_Bcmp_1_L1                                [Bcmp_1]  3.37GB/s ± 1%        3.36GB/s ± 2%     ~     (p=0.102 n=28+29)
BM_LIBC_Bcmp_1_L2                                [Bcmp_1]  3.32GB/s ± 2%        3.30GB/s ± 2%   -0.51%  (p=0.038 n=28+29)
BM_LIBC_Bcmp_1_LLC                               [Bcmp_1]  2.67GB/s ± 4%        2.70GB/s ± 4%   +0.96%  (p=0.009 n=28+27)
BM_LIBC_Bcmp_1_Cold                              [Bcmp_1]   755MB/s ± 1%         751MB/s ± 2%   -0.57%  (p=0.000 n=22+25)
BM_LIBC_Bcmp_2_L1                                [Bcmp_2]  1.79GB/s ± 1%        1.86GB/s ± 2%   +3.92%  (p=0.000 n=27+29)
BM_LIBC_Bcmp_2_L2                                [Bcmp_2]  1.77GB/s ± 2%        1.82GB/s ± 2%   +2.99%  (p=0.000 n=28+29)
BM_LIBC_Bcmp_2_LLC                               [Bcmp_2]  1.41GB/s ± 4%        1.47GB/s ± 3%   +3.97%  (p=0.000 n=28+28)
BM_LIBC_Bcmp_2_Cold                              [Bcmp_2]   386MB/s ± 1%         389MB/s ± 1%   +0.60%  (p=0.000 n=21+23)
BM_LIBC_Bcmp_3_L1                                [Bcmp_3]  2.07GB/s ± 2%        2.17GB/s ± 2%   +4.87%  (p=0.000 n=29+30)
BM_LIBC_Bcmp_3_L2                                [Bcmp_3]  2.07GB/s ± 2%        2.13GB/s ± 2%   +3.02%  (p=0.000 n=28+30)
BM_LIBC_Bcmp_3_LLC                               [Bcmp_3]  1.66GB/s ± 2%        1.73GB/s ± 2%   +4.08%  (p=0.000 n=29+26)
BM_LIBC_Bcmp_3_Cold                              [Bcmp_3]   466MB/s ± 2%         469MB/s ± 3%   +0.66%  (p=0.001 n=22+25)
BM_LIBC_Bcmp_4_L1                                [Bcmp_4]   861MB/s ± 1%         964MB/s ± 2%  +11.98%  (p=0.000 n=29+29)
BM_LIBC_Bcmp_4_L2                                [Bcmp_4]   853MB/s ± 2%         935MB/s ± 2%   +9.54%  (p=0.000 n=28+29)
BM_LIBC_Bcmp_4_LLC                               [Bcmp_4]   707MB/s ± 3%         743MB/s ± 4%   +5.08%  (p=0.000 n=29+29)
BM_LIBC_Bcmp_4_Cold                              [Bcmp_4]   199MB/s ± 3%         199MB/s ± 2%     ~     (p=0.107 n=29+25)
BM_LIBC_Bcmp_5_L1                                [Bcmp_5]  1.65GB/s ± 1%        1.75GB/s ± 2%   +6.15%  (p=0.000 n=29+29)
BM_LIBC_Bcmp_5_L2                                [Bcmp_5]  1.64GB/s ± 3%        1.73GB/s ± 2%   +5.37%  (p=0.000 n=29+29)
BM_LIBC_Bcmp_5_LLC                               [Bcmp_5]  1.32GB/s ± 2%        1.40GB/s ± 2%   +6.21%  (p=0.000 n=28+27)
BM_LIBC_Bcmp_5_Cold                              [Bcmp_5]   370MB/s ± 3%         371MB/s ± 2%   +0.16%  (p=0.008 n=29+25)
BM_LIBC_Bcmp_6_L1                                [Bcmp_6]  3.25GB/s ± 2%        3.47GB/s ± 2%   +6.74%  (p=0.000 n=28+29)
BM_LIBC_Bcmp_6_L2                                [Bcmp_6]  3.26GB/s ± 1%        3.44GB/s ± 1%   +5.43%  (p=0.000 n=28+29)
BM_LIBC_Bcmp_6_LLC                               [Bcmp_6]  2.66GB/s ± 2%        2.79GB/s ± 3%   +4.90%  (p=0.000 n=27+29)
BM_LIBC_Bcmp_6_Cold                              [Bcmp_6]   812MB/s ± 3%         799MB/s ± 2%   -1.57%  (p=0.000 n=29+25)
BM_LIBC_Bcmp_7_L1                                [Bcmp_7]  1.71GB/s ± 2%        1.66GB/s ± 2%   -3.14%  (p=0.000 n=29+29)
BM_LIBC_Bcmp_7_L2                                [Bcmp_7]  1.63GB/s ± 2%        1.59GB/s ± 2%   -2.50%  (p=0.000 n=29+28)
BM_LIBC_Bcmp_7_LLC                               [Bcmp_7]  1.25GB/s ± 4%        1.25GB/s ± 2%     ~     (p=0.530 n=28+26)
BM_LIBC_Bcmp_7_Cold                              [Bcmp_7]   311MB/s ± 3%         308MB/s ± 1%     ~     (p=0.127 n=29+24)
BM_LIBC_Bcmp_8_L1                                [Bcmp_8]   869MB/s ± 2%        1098MB/s ± 2%  +26.28%  (p=0.000 n=27+29)
BM_LIBC_Bcmp_8_L2                                [Bcmp_8]   873MB/s ± 2%        1075MB/s ± 1%  +23.06%  (p=0.000 n=27+29)
BM_LIBC_Bcmp_8_LLC                               [Bcmp_8]   743MB/s ± 4%         859MB/s ± 4%  +15.58%  (p=0.000 n=27+27)
BM_LIBC_Bcmp_8_Cold                              [Bcmp_8]   221MB/s ± 4%         221MB/s ± 3%   +0.14%  (p=0.034 n=29+25)
```

 - ixion-haswell

```
name                                                       old speed            new speed            delta
BM_LIBC_Bcmp_Fleet_L1                                      2.27GB/s ± 5%        2.41GB/s ± 6%   +6.10%  (p=0.000 n=29+28)
BM_LIBC_Bcmp_Fleet_L2                                      2.14GB/s ± 6%        2.33GB/s ± 5%   +9.21%  (p=0.000 n=29+30)
BM_LIBC_Bcmp_Fleet_LLC                                     1.30GB/s ± 9%        1.43GB/s ± 8%   +9.85%  (p=0.000 n=30+30)
BM_LIBC_Bcmp_Fleet_Cold                                     475MB/s ± 6%         475MB/s ± 5%     ~     (p=0.839 n=30+29)
BM_LIBC_Bcmp_0_L1                                [Bcmp_0]  3.38GB/s ± 7%        3.46GB/s ± 6%   +2.35%  (p=0.009 n=30+29)
BM_LIBC_Bcmp_0_L2                                [Bcmp_0]  3.20GB/s ± 5%        3.32GB/s ± 6%   +3.52%  (p=0.000 n=28+30)
BM_LIBC_Bcmp_0_LLC                               [Bcmp_0]  1.88GB/s ± 9%        2.00GB/s ± 6%   +6.63%  (p=0.000 n=30+28)
BM_LIBC_Bcmp_0_Cold                              [Bcmp_0]   664MB/s ± 6%         655MB/s ± 6%   -1.32%  (p=0.025 n=30+30)
BM_LIBC_Bcmp_1_L1                                [Bcmp_1]  3.50GB/s ± 8%        3.61GB/s ±10%   +3.09%  (p=0.001 n=29+30)
BM_LIBC_Bcmp_1_L2                                [Bcmp_1]  3.32GB/s ± 7%        3.48GB/s ± 8%   +4.89%  (p=0.000 n=29+30)
BM_LIBC_Bcmp_1_LLC                               [Bcmp_1]  2.02GB/s ± 7%        2.14GB/s ± 9%   +5.82%  (p=0.000 n=28+29)
BM_LIBC_Bcmp_1_Cold                              [Bcmp_1]   716MB/s ± 6%         709MB/s ± 5%   -0.97%  (p=0.040 n=30+28)
BM_LIBC_Bcmp_2_L1                                [Bcmp_2]  1.83GB/s ± 7%        1.97GB/s ± 8%   +7.90%  (p=0.000 n=30+30)
BM_LIBC_Bcmp_2_L2                                [Bcmp_2]  1.74GB/s ± 6%        1.92GB/s ± 6%  +10.29%  (p=0.000 n=30+29)
BM_LIBC_Bcmp_2_LLC                               [Bcmp_2]  1.05GB/s ± 9%        1.15GB/s ± 9%   +9.73%  (p=0.000 n=30+30)
BM_LIBC_Bcmp_2_Cold                              [Bcmp_2]   379MB/s ± 6%         372MB/s ± 6%   -1.74%  (p=0.012 n=30+30)
BM_LIBC_Bcmp_3_L1                                [Bcmp_3]  2.17GB/s ± 5%        2.29GB/s ± 6%   +5.61%  (p=0.000 n=29+30)
BM_LIBC_Bcmp_3_L2                                [Bcmp_3]  2.02GB/s ± 6%        2.20GB/s ± 6%   +8.75%  (p=0.000 n=29+30)
BM_LIBC_Bcmp_3_LLC                               [Bcmp_3]  1.22GB/s ± 8%        1.34GB/s ± 9%   +9.19%  (p=0.000 n=30+30)
BM_LIBC_Bcmp_3_Cold                              [Bcmp_3]   447MB/s ± 3%         441MB/s ± 7%   -1.40%  (p=0.033 n=30+30)
BM_LIBC_Bcmp_4_L1                                [Bcmp_4]   902MB/s ± 6%         995MB/s ±10%  +10.37%  (p=0.000 n=30+30)
BM_LIBC_Bcmp_4_L2                                [Bcmp_4]   863MB/s ± 5%         945MB/s ±11%   +9.50%  (p=0.000 n=29+30)
BM_LIBC_Bcmp_4_LLC                               [Bcmp_4]   528MB/s ±11%         559MB/s ±12%   +5.75%  (p=0.000 n=30+30)
BM_LIBC_Bcmp_4_Cold                              [Bcmp_4]   183MB/s ± 4%         181MB/s ± 7%     ~     (p=0.088 n=28+30)
BM_LIBC_Bcmp_5_L1                                [Bcmp_5]  1.70GB/s ± 6%        1.87GB/s ± 8%  +10.14%  (p=0.000 n=29+29)
BM_LIBC_Bcmp_5_L2                                [Bcmp_5]  1.60GB/s ± 5%        1.80GB/s ± 9%  +12.61%  (p=0.000 n=29+30)
BM_LIBC_Bcmp_5_LLC                               [Bcmp_5]   994MB/s ±13%        1094MB/s ± 8%  +10.10%  (p=0.000 n=29+30)
BM_LIBC_Bcmp_5_Cold                              [Bcmp_5]   362MB/s ± 6%         358MB/s ± 7%     ~     (p=0.123 n=30+30)
BM_LIBC_Bcmp_6_L1                                [Bcmp_6]  3.31GB/s ± 5%        3.67GB/s ± 6%  +10.90%  (p=0.000 n=28+30)
BM_LIBC_Bcmp_6_L2                                [Bcmp_6]  3.11GB/s ± 5%        3.53GB/s ± 5%  +13.59%  (p=0.000 n=30+30)
BM_LIBC_Bcmp_6_LLC                               [Bcmp_6]  1.98GB/s ± 9%        2.18GB/s ± 8%  +10.34%  (p=0.000 n=30+30)
BM_LIBC_Bcmp_6_Cold                              [Bcmp_6]   754MB/s ± 5%         752MB/s ± 5%     ~     (p=0.592 n=30+30)
BM_LIBC_Bcmp_7_L1                                [Bcmp_7]  1.72GB/s ± 5%        1.72GB/s ± 6%     ~     (p=0.549 n=29+29)
BM_LIBC_Bcmp_7_L2                                [Bcmp_7]  1.61GB/s ± 7%        1.63GB/s ± 8%     ~     (p=0.191 n=30+29)
BM_LIBC_Bcmp_7_LLC                               [Bcmp_7]   913MB/s ± 8%         905MB/s ± 9%     ~     (p=0.423 n=30+30)
BM_LIBC_Bcmp_7_Cold                              [Bcmp_7]   304MB/s ± 6%         287MB/s ± 4%   -5.57%  (p=0.000 n=30+30)
BM_LIBC_Bcmp_8_L1                                [Bcmp_8]   961MB/s ± 5%        1124MB/s ± 6%  +16.94%  (p=0.000 n=30+30)
BM_LIBC_Bcmp_8_L2                                [Bcmp_8]   915MB/s ± 8%        1100MB/s ± 7%  +20.16%  (p=0.000 n=30+30)
BM_LIBC_Bcmp_8_LLC                               [Bcmp_8]   593MB/s ± 8%         669MB/s ± 8%  +12.92%  (p=0.000 n=30+30)
BM_LIBC_Bcmp_8_Cold                              [Bcmp_8]   220MB/s ± 4%         220MB/s ± 6%     ~     (p=0.572 n=30+30)
```

Co-authored-by: goldvitaly@google.com <%username%@google.com>
 [libc][x86] Use prefetch for write for memcpy (#90450) 2024-08-29T12:17:23+00:00 Guillaume Chatelet gchatelet@google.com 2024-08-29T12:17:23+00:00 73ef397fcba35b7b4239c00bf3e0b4e689ca0add Currently when `LIBC_COPT_MEMCPY_X86_USE_SOFTWARE_PREFETCHING` is set we prefetch memory for read on the source buffer. This patch adds prefetch for write on the destination buffer. 
Currently when `LIBC_COPT_MEMCPY_X86_USE_SOFTWARE_PREFETCHING` is set we
prefetch memory for read on the source buffer. This patch adds prefetch
for write on the destination buffer.
 [libc] Migrate to using LIBC_NAMESPACE_DECL for namespace declaration (#98597) 2024-07-12T16:28:41+00:00 Petr Hosek phosek@google.com 2024-07-12T16:28:41+00:00 5ff3ff33ff930e4ec49da7910612d8a41eb068cb This is a part of #97655. 
This is a part of #97655.
 Revert "[libc] Migrate to using LIBC_NAMESPACE_DECL for namespace declaration" (#98593) 2024-07-12T07:12:13+00:00 Mehdi Amini joker.eph@gmail.com 2024-07-12T07:12:13+00:00 ce9035f5bd3aa09cbd899489cdbc7f6c18acf1e3 Reverts llvm/llvm-project#98075 bots are broken 
Reverts llvm/llvm-project#98075

bots are broken
 [libc] Migrate to using LIBC_NAMESPACE_DECL for namespace declaration (#98075) 2024-07-11T19:35:22+00:00 Petr Hosek phosek@google.com 2024-07-11T19:35:22+00:00 3f30effe1bd81fa1b039218a9bfe79c3b03fafad This is a part of #97655. 
This is a part of #97655.
 [libc][bug] Fix out of bound write in memcpy w/ software prefetching (#90591) 2024-05-14T11:55:24+00:00 Guillaume Chatelet gchatelet@google.com 2024-05-14T11:55:24+00:00 292b300c5131e54b9977305bb4aca9a03e1b4fed This patch adds tests for `memcpy` and `memset` making sure that we don't access buffers out of bounds. It relies on POSIX `mmap` / `mprotect` and works only when FULL_BUILD_MODE is disabled. The bug showed up while enabling software prefetching. `loop_and_tail_offset` is always running at least one iteration but in some configurations loop unrolled prefetching was actually needing only the tail operation and no loop iterations at all. 
This patch adds tests for `memcpy` and `memset` making sure that we
don't access buffers out of bounds. It relies on POSIX `mmap` /
`mprotect` and works only when FULL_BUILD_MODE is disabled.

The bug showed up while enabling software prefetching.
`loop_and_tail_offset` is always running at least one iteration but in
some configurations loop unrolled prefetching was actually needing only
the tail operation and no loop iterations at all.
 [libc] fix more readability-identifier-naming lints (#83914) 2024-03-05T16:15:56+00:00 Nick Desaulniers nickdesaulniers@users.noreply.github.com 2024-03-05T16:15:56+00:00 88d82b747cdc521686e6bbc108b021753842a902 Found via: $ ninja -k2000 libc-lint 2>&1 | grep readability-identifier-naming Auto fixed via: $ clang-tidy -p build/compile_commands.json \ -checks="-*,readability-identifier-naming" \ <filename> --fix This doesn't fix all instances, just the obvious simple cases where it makes sense to change the identifier names. Subsequent PRs will fix up the stragglers. 
Found via:

    $ ninja -k2000 libc-lint 2>&1 | grep readability-identifier-naming

Auto fixed via:

    $ clang-tidy -p build/compile_commands.json \
      -checks="-*,readability-identifier-naming" \
      <filename> --fix

This doesn't fix all instances, just the obvious simple cases where it makes
sense to change the identifier names.  Subsequent PRs will fix up the
stragglers.