These are the only variables I could find that use LIBC_INLINE. Note, these are namespace scoped constexpr so local linkage is implied. inline is useful here to silence clang's unused-const-variable variable. For Fuchsia, the distinction between LIBC_INLINE and LIBC_INLINE_VAR is helpful because we define LIBC_INLINE as `[[gnu::always_inline]] inline` when building with gcc. This isn't meaningful on variables.
Alternatively, we could make these variables simply constexpr and also add `[[maybe_unused]]`
Reviewed By: sivachandra, mcgrathr
Differential Revision: https://reviews.llvm.org/D152951
We define LIBC_INLINE to include [[clang::internal_linkage]], and these
must appear before other specifiers. Additionally, there was also a
missing cast that was causing warnings.
Differential Revision: https://reviews.llvm.org/D152865
Most of the time `memmove` is called on buffers that are disjoint, in that case we can use `memcpy` which is faster.
The additional test is branchless on x86, aarch64 and RISCV with the zbb extension (bitmanip).
On x86 this patch adds a latency of 2 to 3 cycles.
Before
```
--------------------------------------------------------------------------------
Benchmark Time CPU Iterations UserCounters...
--------------------------------------------------------------------------------
BM_Memmove/0/0_median 5.00 ns 5.00 ns 10 bytes_per_cycle=1.25477/s bytes_per_second=2.62933G/s items_per_second=199.87M/s __llvm_libc::memmove,memmove Google A
BM_Memmove/1/0_median 6.21 ns 6.21 ns 10 bytes_per_cycle=3.22173/s bytes_per_second=6.75106G/s items_per_second=160.955M/s __llvm_libc::memmove,memmove Google B
BM_Memmove/2/0_median 8.09 ns 8.09 ns 10 bytes_per_cycle=5.31462/s bytes_per_second=11.1366G/s items_per_second=123.603M/s __llvm_libc::memmove,memmove Google D
BM_Memmove/3/0_median 5.95 ns 5.95 ns 10 bytes_per_cycle=2.71865/s bytes_per_second=5.69687G/s items_per_second=167.967M/s __llvm_libc::memmove,memmove Google L
BM_Memmove/4/0_median 5.63 ns 5.63 ns 10 bytes_per_cycle=2.28294/s bytes_per_second=4.78383G/s items_per_second=177.615M/s __llvm_libc::memmove,memmove Google M
BM_Memmove/5/0_median 5.68 ns 5.68 ns 10 bytes_per_cycle=2.16798/s bytes_per_second=4.54295G/s items_per_second=176.015M/s __llvm_libc::memmove,memmove Google Q
BM_Memmove/6/0_median 7.46 ns 7.46 ns 10 bytes_per_cycle=3.97619/s bytes_per_second=8.332G/s items_per_second=134.044M/s __llvm_libc::memmove,memmove Google S
BM_Memmove/7/0_median 5.40 ns 5.40 ns 10 bytes_per_cycle=1.79695/s bytes_per_second=3.76546G/s items_per_second=185.211M/s __llvm_libc::memmove,memmove Google U
BM_Memmove/8/0_median 5.62 ns 5.62 ns 10 bytes_per_cycle=3.18747/s bytes_per_second=6.67927G/s items_per_second=177.983M/s __llvm_libc::memmove,memmove Google W
BM_Memmove/9/0_median 101 ns 101 ns 10 bytes_per_cycle=9.77359/s bytes_per_second=20.4803G/s items_per_second=9.9333M/s __llvm_libc::memmove,uniform 384 to 4096
```
After
```
BM_Memmove/0/0_median 3.57 ns 3.57 ns 10 bytes_per_cycle=1.71375/s bytes_per_second=3.59112G/s items_per_second=280.411M/s __llvm_libc::memmove,memmove Google A
BM_Memmove/1/0_median 4.52 ns 4.52 ns 10 bytes_per_cycle=4.47557/s bytes_per_second=9.37843G/s items_per_second=221.427M/s __llvm_libc::memmove,memmove Google B
BM_Memmove/2/0_median 5.70 ns 5.70 ns 10 bytes_per_cycle=7.37396/s bytes_per_second=15.4519G/s items_per_second=175.399M/s __llvm_libc::memmove,memmove Google D
BM_Memmove/3/0_median 4.47 ns 4.47 ns 10 bytes_per_cycle=3.4148/s bytes_per_second=7.15563G/s items_per_second=223.743M/s __llvm_libc::memmove,memmove Google L
BM_Memmove/4/0_median 4.53 ns 4.53 ns 10 bytes_per_cycle=2.86071/s bytes_per_second=5.99454G/s items_per_second=220.69M/s __llvm_libc::memmove,memmove Google M
BM_Memmove/5/0_median 4.19 ns 4.19 ns 10 bytes_per_cycle=2.5484/s bytes_per_second=5.3401G/s items_per_second=238.924M/s __llvm_libc::memmove,memmove Google Q
BM_Memmove/6/0_median 5.02 ns 5.02 ns 10 bytes_per_cycle=5.94164/s bytes_per_second=12.4505G/s items_per_second=199.14M/s __llvm_libc::memmove,memmove Google S
BM_Memmove/7/0_median 4.03 ns 4.03 ns 10 bytes_per_cycle=2.47028/s bytes_per_second=5.17641G/s items_per_second=247.906M/s __llvm_libc::memmove,memmove Google U
BM_Memmove/8/0_median 4.70 ns 4.70 ns 10 bytes_per_cycle=3.84975/s bytes_per_second=8.06706G/s items_per_second=212.72M/s __llvm_libc::memmove,memmove Google W
BM_Memmove/9/0_median 90.7 ns 90.7 ns 10 bytes_per_cycle=10.8681/s bytes_per_second=22.7739G/s items_per_second=11.02M/s __llvm_libc::memmove,uniform 384 to 4096
```
Reviewed By: courbet
Differential Revision: https://reviews.llvm.org/D152811
This is based on ideas from @nafi to:
- use a branchless version of 'cmp' for 'uint32_t',
- completely resolve the lexicographic comparison through vector
operations when wide types are available. We also get rid of byte
reloads and serializing '__builtin_ctzll'.
I did not include the suggestion to replace comparisons of 'uint16_t'
with two 'uint8_t' as it did not seem to help the codegen. This can
be revisited in sub-sequent patches.
The code been rewritten to reduce nested function calls, making the
job of the inliner easier and preventing harmful code duplication.
Reviewed By: nafi3000
Differential Revision: https://reviews.llvm.org/D148717
This is based on ideas from @nafi to:
- use a branchless version of 'cmp' for 'uint32_t',
- completely resolve the lexicographic comparison through vector
operations when wide types are available. We also get rid of byte
reloads and serializing '__builtin_ctzll'.
I did not include the suggestion to replace comparisons of 'uint16_t'
with two 'uint8_t' as it did not seem to help the codegen. This can
be revisited in sub-sequent patches.
The code been rewritten to reduce nested function calls, making the
job of the inliner easier and preventing harmful code duplication.
Reviewed By: nafi3000
Differential Revision: https://reviews.llvm.org/D148717
This is based on ideas from @nafi to:
- use a branchless version of 'cmp' for 'uint32_t',
- completely resolve the lexicographic comparison through vector
operations when wide types are available. We also get rid of byte
reloads and serializing '__builtin_ctzll'.
I did not include the suggestion to replace comparisons of 'uint16_t'
with two 'uint8_t' as it did not seem to help the codegen. This can
be revisited in sub-sequent patches.
The code been rewritten to reduce nested function calls, making the
job of the inliner easier and preventing harmful code duplication.
Reviewed By: nafi3000
Differential Revision: https://reviews.llvm.org/D148717
This patch adds two versions of `bcmp` optimized for architectures where unaligned accesses are either illegal or extremely slow.
It is currently enabled for RISCV 64 and RISCV 32 but it could be used for ARM 32 architectures as well.
Here is the before / after output of `libc.benchmarks.memory_functions.opt_host --benchmark_filter=BM_memcmp` on a quad core Linux starfive RISCV 64 board running at 1.5GHz.
Before
```
Run on (4 X 1500 MHz CPU s)
CPU Caches:
L1 Instruction 32 KiB (x4)
L1 Data 32 KiB (x4)
L2 Unified 2048 KiB (x1)
----------------------------------------------------------------------
Benchmark Time CPU Iterations UserCounters...
----------------------------------------------------------------------
BM_Memcmp/0/0 110 ns 66.4 ns 10404864 bytes_per_cycle=0.107646/s bytes_per_second=153.989M/s items_per_second=15.071M/s __llvm_libc::memcmp,memcmp Google A
BM_Memcmp/1/0 318 ns 211 ns 3026944 bytes_per_cycle=0.131539/s bytes_per_second=188.167M/s items_per_second=4.73691M/s __llvm_libc::memcmp,memcmp Google B
BM_Memcmp/2/0 204 ns 115 ns 6118400 bytes_per_cycle=0.121675/s bytes_per_second=174.058M/s items_per_second=8.70241M/s __llvm_libc::memcmp,memcmp Google D
BM_Memcmp/3/0 143 ns 99.6 ns 7013376 bytes_per_cycle=0.117974/s bytes_per_second=168.763M/s items_per_second=10.0437M/s __llvm_libc::memcmp,memcmp Google L
BM_Memcmp/4/0 81.3 ns 58.2 ns 11426816 bytes_per_cycle=0.101125/s bytes_per_second=144.661M/s items_per_second=17.1805M/s __llvm_libc::memcmp,memcmp Google M
BM_Memcmp/5/0 177 ns 118 ns 5952512 bytes_per_cycle=0.120612/s bytes_per_second=172.537M/s items_per_second=8.45549M/s __llvm_libc::memcmp,memcmp Google Q
BM_Memcmp/6/0 342 ns 220 ns 3483648 bytes_per_cycle=0.132004/s bytes_per_second=188.834M/s items_per_second=4.54739M/s __llvm_libc::memcmp,memcmp Google S
BM_Memcmp/7/0 208 ns 130 ns 5681152 bytes_per_cycle=0.12468/s bytes_per_second=178.356M/s items_per_second=7.6674M/s __llvm_libc::memcmp,memcmp Google U
BM_Memcmp/8/0 123 ns 79.1 ns 8387584 bytes_per_cycle=0.110593/s bytes_per_second=158.204M/s items_per_second=12.6439M/s __llvm_libc::memcmp,memcmp Google W
BM_Memcmp/9/0 20707 ns 10643 ns 67584 bytes_per_cycle=0.142401/s bytes_per_second=203.707M/s items_per_second=93.9559k/s __llvm_libc::memcmp,uniform 384 to 4096
```
After
```
BM_Memcmp/0/0 80.4 ns 55.8 ns 12648448 bytes_per_cycle=0.132703/s bytes_per_second=189.834M/s items_per_second=17.9256M/s __llvm_libc::memcmp,memcmp Google A
BM_Memcmp/1/0 140 ns 80.5 ns 8230912 bytes_per_cycle=0.337273/s bytes_per_second=482.474M/s items_per_second=12.4165M/s __llvm_libc::memcmp,memcmp Google B
BM_Memcmp/2/0 101 ns 66.4 ns 10571776 bytes_per_cycle=0.208539/s bytes_per_second=298.317M/s items_per_second=15.0687M/s __llvm_libc::memcmp,memcmp Google D
BM_Memcmp/3/0 118 ns 67.6 ns 10533888 bytes_per_cycle=0.176822/s bytes_per_second=252.946M/s items_per_second=14.7946M/s __llvm_libc::memcmp,memcmp Google L
BM_Memcmp/4/0 106 ns 53.0 ns 12722176 bytes_per_cycle=0.111141/s bytes_per_second=158.988M/s items_per_second=18.8591M/s __llvm_libc::memcmp,memcmp Google M
BM_Memcmp/5/0 141 ns 70.2 ns 10436608 bytes_per_cycle=0.26032/s bytes_per_second=372.39M/s items_per_second=14.2458M/s __llvm_libc::memcmp,memcmp Google Q
BM_Memcmp/6/0 144 ns 79.3 ns 8932352 bytes_per_cycle=0.353168/s bytes_per_second=505.211M/s items_per_second=12.612M/s __llvm_libc::memcmp,memcmp Google S
BM_Memcmp/7/0 123 ns 71.7 ns 9945088 bytes_per_cycle=0.22143/s bytes_per_second=316.758M/s items_per_second=13.9421M/s __llvm_libc::memcmp,memcmp Google U
BM_Memcmp/8/0 97.0 ns 56.2 ns 12509184 bytes_per_cycle=0.160526/s bytes_per_second=229.635M/s items_per_second=17.7784M/s __llvm_libc::memcmp,memcmp Google W
BM_Memcmp/9/0 1840 ns 989 ns 676864 bytes_per_cycle=1.4894/s bytes_per_second=2.08067G/s items_per_second=1010.92k/s __llvm_libc::memcmp,uniform 384 to 4096
```
glibc
```
BM_Memcmp/0/0 72.6 ns 51.7 ns 12963840 bytes_per_cycle=0.141261/s bytes_per_second=202.075M/s items_per_second=19.3246M/s glibc::memcmp,memcmp Google A
BM_Memcmp/1/0 118 ns 75.2 ns 9280512 bytes_per_cycle=0.354054/s bytes_per_second=506.478M/s items_per_second=13.3046M/s glibc::memcmp,memcmp Google B
BM_Memcmp/2/0 114 ns 62.9 ns 11152384 bytes_per_cycle=0.222675/s bytes_per_second=318.539M/s items_per_second=15.8943M/s glibc::memcmp,memcmp Google D
BM_Memcmp/3/0 84.0 ns 63.5 ns 11030528 bytes_per_cycle=0.186353/s bytes_per_second=266.581M/s items_per_second=15.7378M/s glibc::memcmp,memcmp Google L
BM_Memcmp/4/0 93.5 ns 51.2 ns 13462528 bytes_per_cycle=0.119215/s bytes_per_second=170.539M/s items_per_second=19.5384M/s glibc::memcmp,memcmp Google M
BM_Memcmp/5/0 123 ns 61.7 ns 11376640 bytes_per_cycle=0.225262/s bytes_per_second=322.239M/s items_per_second=16.1993M/s glibc::memcmp,memcmp Google Q
BM_Memcmp/6/0 122 ns 71.6 ns 9967616 bytes_per_cycle=0.380844/s bytes_per_second=544.802M/s items_per_second=13.9579M/s glibc::memcmp,memcmp Google S
BM_Memcmp/7/0 118 ns 65.6 ns 10555392 bytes_per_cycle=0.238677/s bytes_per_second=341.43M/s items_per_second=15.2334M/s glibc::memcmp,memcmp Google U
BM_Memcmp/8/0 90.4 ns 54.0 ns 12920832 bytes_per_cycle=0.161987/s bytes_per_second=231.724M/s items_per_second=18.5169M/s glibc::memcmp,memcmp Google W
BM_Memcmp/9/0 1045 ns 601 ns 1195008 bytes_per_cycle=2.53677/s bytes_per_second=3.54383G/s items_per_second=1.66423M/s glibc::memcmp,uniform 384 to 4096
```
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D150663
[libc] Add optimized bcmp for RISCV
This patch adds two versions of bcmp optimized for architectures where unaligned accesses are either illegal or extremely slow.
It is currently enabled for RISCV 64 and RISCV 32 but it could be used for ARM 32 architectures as well.
Here is the before / after output of libc.benchmarks.memory_functions.opt_host --benchmark_filter=BM_Bcmp on a quad core Linux starfive RISCV 64 board running at 1.5GHz.
Before
```
Run on (4 X 1500 MHz CPU s)
CPU Caches:
L1 Instruction 32 KiB (x4)
L1 Data 32 KiB (x4)
L2 Unified 2048 KiB (x1)
Load Average: 7.03, 5.98, 3.71
----------------------------------------------------------------------
Benchmark Time CPU Iterations UserCounters...
----------------------------------------------------------------------
BM_Bcmp/0/0 102 ns 60.5 ns 11662336 bytes_per_cycle=0.122696/s bytes_per_second=175.518M/s items_per_second=16.5258M/s __llvm_libc::bcmp,memcmp Google A
BM_Bcmp/1/0 328 ns 172 ns 3737600 bytes_per_cycle=0.15256/s bytes_per_second=218.238M/s items_per_second=5.80575M/s __llvm_libc::bcmp,memcmp Google B
BM_Bcmp/2/0 199 ns 99.7 ns 7019520 bytes_per_cycle=0.141897/s bytes_per_second=202.986M/s items_per_second=10.032M/s __llvm_libc::bcmp,memcmp Google D
BM_Bcmp/3/0 173 ns 86.5 ns 8361984 bytes_per_cycle=0.13863/s bytes_per_second=198.312M/s items_per_second=11.5669M/s __llvm_libc::bcmp,memcmp Google L
BM_Bcmp/4/0 105 ns 51.8 ns 13213696 bytes_per_cycle=0.116399/s bytes_per_second=166.51M/s items_per_second=19.2931M/s __llvm_libc::bcmp,memcmp Google M
BM_Bcmp/5/0 167 ns 93.9 ns 7853056 bytes_per_cycle=0.139432/s bytes_per_second=199.459M/s items_per_second=10.6503M/s __llvm_libc::bcmp,memcmp Google Q
BM_Bcmp/6/0 262 ns 165 ns 3931136 bytes_per_cycle=0.151516/s bytes_per_second=216.745M/s items_per_second=6.07091M/s __llvm_libc::bcmp,memcmp Google S
BM_Bcmp/7/0 168 ns 105 ns 6665216 bytes_per_cycle=0.143159/s bytes_per_second=204.791M/s items_per_second=9.52163M/s __llvm_libc::bcmp,memcmp Google U
BM_Bcmp/8/0 108 ns 68.0 ns 10175488 bytes_per_cycle=0.125504/s bytes_per_second=179.535M/s items_per_second=14.701M/s __llvm_libc::bcmp,memcmp Google W
BM_Bcmp/9/0 15371 ns 9007 ns 78848 bytes_per_cycle=0.166128/s bytes_per_second=237.648M/s items_per_second=111.031k/s __llvm_libc::bcmp,uniform 384 to 4096
```
After
```
BM_Bcmp/0/0 74.2 ns 49.7 ns 14306304 bytes_per_cycle=0.148927/s bytes_per_second=213.042M/s items_per_second=20.1101M/s __llvm_libc::bcmp,memcmp Google A
BM_Bcmp/1/0 108 ns 68.1 ns 10350592 bytes_per_cycle=0.411197/s bytes_per_second=588.222M/s items_per_second=14.6849M/s __llvm_libc::bcmp,memcmp Google B
BM_Bcmp/2/0 80.2 ns 56.0 ns 12386304 bytes_per_cycle=0.258588/s bytes_per_second=369.912M/s items_per_second=17.8585M/s __llvm_libc::bcmp,memcmp Google D
BM_Bcmp/3/0 92.4 ns 55.7 ns 12555264 bytes_per_cycle=0.206835/s bytes_per_second=295.88M/s items_per_second=17.943M/s __llvm_libc::bcmp,memcmp Google L
BM_Bcmp/4/0 79.3 ns 46.8 ns 14288896 bytes_per_cycle=0.125872/s bytes_per_second=180.061M/s items_per_second=21.3611M/s __llvm_libc::bcmp,memcmp Google M
BM_Bcmp/5/0 98.0 ns 57.9 ns 12232704 bytes_per_cycle=0.268815/s bytes_per_second=384.543M/s items_per_second=17.2711M/s __llvm_libc::bcmp,memcmp Google Q
BM_Bcmp/6/0 132 ns 65.5 ns 10474496 bytes_per_cycle=0.417246/s bytes_per_second=596.875M/s items_per_second=15.2673M/s __llvm_libc::bcmp,memcmp Google S
BM_Bcmp/7/0 101 ns 60.9 ns 11505664 bytes_per_cycle=0.253733/s bytes_per_second=362.968M/s items_per_second=16.4202M/s __llvm_libc::bcmp,memcmp Google U
BM_Bcmp/8/0 72.5 ns 50.2 ns 14082048 bytes_per_cycle=0.183262/s bytes_per_second=262.158M/s items_per_second=19.9271M/s __llvm_libc::bcmp,memcmp Google W
BM_Bcmp/9/0 852 ns 803 ns 854016 bytes_per_cycle=1.85028/s bytes_per_second=2.58481G/s items_per_second=1.24597M/s __llvm_libc::bcmp,uniform 384 to 4096
```
For comparison with glibc
```
BM_Bcmp/0/0 106 ns 52.6 ns 12906496 bytes_per_cycle=0.142072/s bytes_per_second=203.235M/s items_per_second=19.0271M/s glibc::bcmp,memcmp Google A
BM_Bcmp/1/0 132 ns 77.1 ns 8905728 bytes_per_cycle=0.365072/s bytes_per_second=522.239M/s items_per_second=12.9782M/s glibc::bcmp,memcmp Google B
BM_Bcmp/2/0 122 ns 62.3 ns 10909696 bytes_per_cycle=0.222667/s bytes_per_second=318.527M/s items_per_second=16.0563M/s glibc::bcmp,memcmp Google D
BM_Bcmp/3/0 99.5 ns 64.2 ns 11074560 bytes_per_cycle=0.185126/s bytes_per_second=264.825M/s items_per_second=15.5674M/s glibc::bcmp,memcmp Google L
BM_Bcmp/4/0 86.6 ns 50.2 ns 13488128 bytes_per_cycle=0.117941/s bytes_per_second=168.717M/s items_per_second=19.9053M/s glibc::bcmp,memcmp Google M
BM_Bcmp/5/0 106 ns 61.4 ns 11344896 bytes_per_cycle=0.248968/s bytes_per_second=356.151M/s items_per_second=16.284M/s glibc::bcmp,memcmp Google Q
BM_Bcmp/6/0 145 ns 71.9 ns 10046464 bytes_per_cycle=0.389814/s bytes_per_second=557.633M/s items_per_second=13.9019M/s glibc::bcmp,memcmp Google S
BM_Bcmp/7/0 119 ns 65.6 ns 10718208 bytes_per_cycle=0.243756/s bytes_per_second=348.696M/s items_per_second=15.2329M/s glibc::bcmp,memcmp Google U
BM_Bcmp/8/0 86.4 ns 54.5 ns 13250560 bytes_per_cycle=0.154831/s bytes_per_second=221.488M/s items_per_second=18.3532M/s glibc::bcmp,memcmp Google W
BM_Bcmp/9/0 1090 ns 604 ns 1186816 bytes_per_cycle=2.53848/s bytes_per_second=3.54622G/s items_per_second=1.65598M/s glibc::bcmp,uniform 384 to 4096
```
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D150567
This patch adds two versions of `memset` optimized for architectures where unaligned accesses are either illegal or extremely slow.
It is currently enabled for RISCV 64 and RISCV 32 but it could be used for ARM 32 architectures as well.
Here is the before / after output of libc.benchmarks.memory_functions.opt_host --benchmark_filter=BM_Memset on a quad core Linux starfive RISCV 64 board running at 1.5GHz.
Before
```
Run on (4 X 1500 MHz CPU s)
CPU Caches:
L1 Instruction 32 KiB (x4)
L1 Data 32 KiB (x4)
L2 Unified 2048 KiB (x1)
------------------------------------------------------------------------
Benchmark Time CPU Iterations UserCounters...
------------------------------------------------------------------------
BM_Memset/0/0 506 ns 252 ns 2883584 bytes_per_cycle=0.238312/s bytes_per_second=340.908M/s items_per_second=3.96043M/s __llvm_libc::memset,memset Google A
BM_Memset/1/0 296 ns 189 ns 2900992 bytes_per_cycle=0.234589/s bytes_per_second=335.583M/s items_per_second=5.29382M/s __llvm_libc::memset,memset Google B
BM_Memset/2/0 2110 ns 1049 ns 678912 bytes_per_cycle=0.24687/s bytes_per_second=353.151M/s items_per_second=953.527k/s __llvm_libc::memset,memset Google D
BM_Memset/3/0 397 ns 254 ns 3055616 bytes_per_cycle=0.238479/s bytes_per_second=341.147M/s items_per_second=3.93224M/s __llvm_libc::memset,memset Google L
BM_Memset/4/0 1119 ns 621 ns 1079296 bytes_per_cycle=0.244925/s bytes_per_second=350.368M/s items_per_second=1.61047M/s __llvm_libc::memset,memset Google M
BM_Memset/5/0 605 ns 349 ns 1644544 bytes_per_cycle=0.241364/s bytes_per_second=345.274M/s items_per_second=2.8614M/s __llvm_libc::memset,memset Google Q
BM_Memset/6/0 472 ns 271 ns 2310144 bytes_per_cycle=0.238615/s bytes_per_second=341.341M/s items_per_second=3.68799M/s __llvm_libc::memset,memset Google S
BM_Memset/7/0 262 ns 143 ns 3956736 bytes_per_cycle=0.225812/s bytes_per_second=323.026M/s items_per_second=7.0087M/s __llvm_libc::memset,memset Google U
BM_Memset/8/0 454 ns 261 ns 2940928 bytes_per_cycle=0.238883/s bytes_per_second=341.725M/s items_per_second=3.82716M/s __llvm_libc::memset,memset Google W
BM_Memset/9/0 8768 ns 5998 ns 115712 bytes_per_cycle=0.249196/s bytes_per_second=356.478M/s items_per_second=166.724k/s __llvm_libc::memset,uniform 384 to 4096
```
After
```
BM_Memset/0/0 117 ns 69.5 ns 9761792 bytes_per_cycle=0.935152/s bytes_per_second=1.30639G/s items_per_second=14.3834M/s __llvm_libc::memset,memset Google A
BM_Memset/1/0 97.8 ns 58.5 ns 13002752 bytes_per_cycle=0.892814/s bytes_per_second=1.24725G/s items_per_second=17.0848M/s __llvm_libc::memset,memset Google B
BM_Memset/2/0 326 ns 163 ns 5156864 bytes_per_cycle=1.54408/s bytes_per_second=2.15706G/s items_per_second=6.1192M/s __llvm_libc::memset,memset Google D
BM_Memset/3/0 132 ns 65.4 ns 11455488 bytes_per_cycle=0.876411/s bytes_per_second=1.22433G/s items_per_second=15.2803M/s __llvm_libc::memset,memset Google L
BM_Memset/4/0 222 ns 120 ns 6405120 bytes_per_cycle=1.44398/s bytes_per_second=2.01722G/s items_per_second=8.30758M/s __llvm_libc::memset,memset Google M
BM_Memset/5/0 119 ns 79.2 ns 8930304 bytes_per_cycle=1.13327/s bytes_per_second=1.58317G/s items_per_second=12.6189M/s __llvm_libc::memset,memset Google Q
BM_Memset/6/0 123 ns 64.0 ns 11609088 bytes_per_cycle=1.008/s bytes_per_second=1.40817G/s items_per_second=15.6365M/s __llvm_libc::memset,memset Google S
BM_Memset/7/0 85.9 ns 52.1 ns 12423168 bytes_per_cycle=0.641164/s bytes_per_second=917.192M/s items_per_second=19.1937M/s __llvm_libc::memset,memset Google U
BM_Memset/8/0 114 ns 67.1 ns 10347520 bytes_per_cycle=0.911968/s bytes_per_second=1.274G/s items_per_second=14.9015M/s __llvm_libc::memset,memset Google W
BM_Memset/9/0 1326 ns 785 ns 907264 bytes_per_cycle=1.89716/s bytes_per_second=2.6503G/s items_per_second=1.27348M/s __llvm_libc::memset,uniform 384 to 4096
```
Again not as good as current glibc but it's a first step in the right direction.
```
BM_Memset/0/0 108 ns 53.6 ns 12894208 bytes_per_cycle=1.02858/s bytes_per_second=1.4369G/s items_per_second=18.668M/s glibc::memset,memset Google A
BM_Memset/1/0 84.6 ns 47.6 ns 14284800 bytes_per_cycle=1.00197/s bytes_per_second=1.39974G/s items_per_second=21.0256M/s glibc::memset,memset Google B
BM_Memset/2/0 160 ns 85.8 ns 8927232 bytes_per_cycle=3.30805/s bytes_per_second=4.62129G/s items_per_second=11.6596M/s glibc::memset,memset Google D
BM_Memset/3/0 78.9 ns 53.6 ns 13326336 bytes_per_cycle=1.14058/s bytes_per_second=1.59338G/s items_per_second=18.674M/s glibc::memset,memset Google L
BM_Memset/4/0 99.2 ns 60.8 ns 11460608 bytes_per_cycle=2.54751/s bytes_per_second=3.55884G/s items_per_second=16.4587M/s glibc::memset,memset Google M
BM_Memset/5/0 93.0 ns 56.1 ns 12219392 bytes_per_cycle=1.73379/s bytes_per_second=2.42207G/s items_per_second=17.8157M/s glibc::memset,memset Google Q
BM_Memset/6/0 89.4 ns 47.2 ns 14692352 bytes_per_cycle=1.34846/s bytes_per_second=1.88377G/s items_per_second=21.1795M/s glibc::memset,memset Google S
BM_Memset/7/0 84.0 ns 50.0 ns 14468096 bytes_per_cycle=0.911198/s bytes_per_second=1.27293G/s items_per_second=19.994M/s glibc::memset,memset Google U
BM_Memset/8/0 93.4 ns 52.8 ns 13063168 bytes_per_cycle=1.06642/s bytes_per_second=1.48977G/s items_per_second=18.9524M/s glibc::memset,memset Google W
BM_Memset/9/0 438 ns 241 ns 2853888 bytes_per_cycle=6.1185/s bytes_per_second=8.54744G/s items_per_second=4.15064M/s glibc::memset,uniform 384 to 4096
```
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D150433
This patch adds two versions of memcpy optimized for architectures where unaligned accesses are either illegal or extremely slow.
It is currently enabled for RISCV 64 and RISCV 32 but it could be used for ARM 32 architectures as well.
Here is the before / after output of `libc.benchmarks.memory_functions.opt_host --benchmark_filter=BM_Memcpy` on a quad core Linux starfive RISCV 64 board running at 1.5GHz.
Before:
```
Run on (4 X 1500 MHz CPU s)
CPU Caches:
L1 Instruction 32 KiB (x4)
L1 Data 32 KiB (x4)
L2 Unified 2048 KiB (x1)
------------------------------------------------------------------------
Benchmark Time CPU Iterations UserCounters...
------------------------------------------------------------------------
BM_Memcpy/0/0 474 ns 474 ns 1483776 bytes_per_cycle=0.243492/s bytes_per_second=348.318M/s items_per_second=2.11097M/s __llvm_libc::memcpy,memcpy Google A
BM_Memcpy/1/0 210 ns 209 ns 3649536 bytes_per_cycle=0.233819/s bytes_per_second=334.481M/s items_per_second=4.77519M/s __llvm_libc::memcpy,memcpy Google B
BM_Memcpy/2/0 1814 ns 1814 ns 396288 bytes_per_cycle=0.247899/s bytes_per_second=354.622M/s items_per_second=551.402k/s __llvm_libc::memcpy,memcpy Google D
BM_Memcpy/3/0 89.3 ns 89.2 ns 7459840 bytes_per_cycle=0.217415/s bytes_per_second=311.014M/s items_per_second=11.2071M/s __llvm_libc::memcpy,memcpy Google L
BM_Memcpy/4/0 134 ns 134 ns 3815424 bytes_per_cycle=0.226584/s bytes_per_second=324.131M/s items_per_second=7.44567M/s __llvm_libc::memcpy,memcpy Google M
BM_Memcpy/5/0 52.8 ns 52.6 ns 11001856 bytes_per_cycle=0.194893/s bytes_per_second=278.797M/s items_per_second=19.0284M/s __llvm_libc::memcpy,memcpy Google Q
BM_Memcpy/6/0 180 ns 180 ns 4101120 bytes_per_cycle=0.231884/s bytes_per_second=331.713M/s items_per_second=5.55957M/s __llvm_libc::memcpy,memcpy Google S
BM_Memcpy/7/0 195 ns 195 ns 3906560 bytes_per_cycle=0.232951/s bytes_per_second=333.239M/s items_per_second=5.1217M/s __llvm_libc::memcpy,memcpy Google U
BM_Memcpy/8/0 152 ns 152 ns 4789248 bytes_per_cycle=0.227507/s bytes_per_second=325.452M/s items_per_second=6.58187M/s __llvm_libc::memcpy,memcpy Google W
BM_Memcpy/9/0 6036 ns 6033 ns 118784 bytes_per_cycle=0.249158/s bytes_per_second=356.423M/s items_per_second=165.75k/s __llvm_libc::memcpy,uniform 384 to 4096
```
After:
```
BM_Memcpy/0/0 126 ns 126 ns 5770240 bytes_per_cycle=1.04707/s bytes_per_second=1.46273G/s items_per_second=7.9385M/s __llvm_libc::memcpy,memcpy Google A
BM_Memcpy/1/0 75.1 ns 75.0 ns 10204160 bytes_per_cycle=0.691143/s bytes_per_second=988.687M/s items_per_second=13.3289M/s __llvm_libc::memcpy,memcpy Google B
BM_Memcpy/2/0 333 ns 333 ns 2174976 bytes_per_cycle=1.39297/s bytes_per_second=1.94596G/s items_per_second=3.00002M/s __llvm_libc::memcpy,memcpy Google D
BM_Memcpy/3/0 49.6 ns 49.5 ns 16092160 bytes_per_cycle=0.710161/s bytes_per_second=1015.89M/s items_per_second=20.1844M/s __llvm_libc::memcpy,memcpy Google L
BM_Memcpy/4/0 57.7 ns 57.7 ns 11213824 bytes_per_cycle=0.561557/s bytes_per_second=803.314M/s items_per_second=17.3228M/s __llvm_libc::memcpy,memcpy Google M
BM_Memcpy/5/0 48.0 ns 47.9 ns 16437248 bytes_per_cycle=0.346708/s bytes_per_second=495.97M/s items_per_second=20.8571M/s __llvm_libc::memcpy,memcpy Google Q
BM_Memcpy/6/0 67.5 ns 67.5 ns 10616832 bytes_per_cycle=0.614173/s bytes_per_second=878.582M/s items_per_second=14.8142M/s __llvm_libc::memcpy,memcpy Google S
BM_Memcpy/7/0 84.7 ns 84.6 ns 10480640 bytes_per_cycle=0.819077/s bytes_per_second=1.14424G/s items_per_second=11.8174M/s __llvm_libc::memcpy,memcpy Google U
BM_Memcpy/8/0 61.7 ns 61.6 ns 11191296 bytes_per_cycle=0.550078/s bytes_per_second=786.893M/s items_per_second=16.2279M/s __llvm_libc::memcpy,memcpy Google W
BM_Memcpy/9/0 981 ns 981 ns 703488 bytes_per_cycle=1.52333/s bytes_per_second=2.12807G/s items_per_second=1019.81k/s __llvm_libc::memcpy,uniform 384 to 4096
```
It is not as good as glibc for now so there's room for improvement. I suspect a path pumping 16 bytes at once given the doubled numbers for large copies.
```
BM_Memcpy/0/1 146 ns 82.5 ns 8576000 bytes_per_cycle=1.35236/s bytes_per_second=1.88922G/s items_per_second=12.1169M/s glibc memcpy,memcpy Google A
BM_Memcpy/1/1 112 ns 63.7 ns 10634240 bytes_per_cycle=0.628018/s bytes_per_second=898.387M/s items_per_second=15.702M/s glibc memcpy,memcpy Google B
BM_Memcpy/2/1 315 ns 180 ns 4079616 bytes_per_cycle=2.65229/s bytes_per_second=3.7052G/s items_per_second=5.54764M/s glibc memcpy,memcpy Google D
BM_Memcpy/3/1 85.3 ns 43.1 ns 15854592 bytes_per_cycle=0.774164/s bytes_per_second=1107.45M/s items_per_second=23.2249M/s glibc memcpy,memcpy Google L
BM_Memcpy/4/1 105 ns 54.3 ns 13427712 bytes_per_cycle=0.7793/s bytes_per_second=1114.8M/s items_per_second=18.4109M/s glibc memcpy,memcpy Google M
BM_Memcpy/5/1 77.1 ns 43.2 ns 16476160 bytes_per_cycle=0.279808/s bytes_per_second=400.269M/s items_per_second=23.1428M/s glibc memcpy,memcpy Google Q
BM_Memcpy/6/1 112 ns 62.7 ns 11236352 bytes_per_cycle=0.676078/s bytes_per_second=967.137M/s items_per_second=15.9387M/s glibc memcpy,memcpy Google S
BM_Memcpy/7/1 131 ns 65.5 ns 11751424 bytes_per_cycle=0.965616/s bytes_per_second=1.34895G/s items_per_second=15.2762M/s glibc memcpy,memcpy Google U
BM_Memcpy/8/1 104 ns 55.0 ns 12314624 bytes_per_cycle=0.583336/s bytes_per_second=834.468M/s items_per_second=18.1937M/s glibc memcpy,memcpy Google W
BM_Memcpy/9/1 932 ns 466 ns 1480704 bytes_per_cycle=3.17342/s bytes_per_second=4.43321G/s items_per_second=2.14679M/s glibc memcpy,uniform 384 to 4096
```
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D150202
Introduce the `memmem` libc string function.
`memmem_implementation` performs shared logic for `strstr`,
`strcasestr`, and `memmem`; essentially reconfiguring what was the
`strstr_implementation` to support length parameters.
Differential Revision: https://reviews.llvm.org/D147822
Introduce `strxfrm` and unit tests. The current implementation is
introduced without locale support.
The simplified function performs a `memcpy` if the `n` value is large
enough to store the source len + '\0', otherwise `dest` is unmodified.
Ticket: https://fxbug.dev/124217
Differential Revision: https://reviews.llvm.org/D147478
Memory functions get the basic implementation. They can be tuned
as a follow up.
Reviewed By: michaelrj, lntue
Differential Revision: https://reviews.llvm.org/D145433
This is in preparation for the transition to a solution to make libc tests
hermetic with respect to their use of errno. The implementation of strdup
has been switched over to libc_errno as an example of what the code looks
like in the new way.
See #61037 for more information.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D144928
