AuroraMiddleware/glibc
1
0
Fork 0
mirror of https://sourceware.org/git/glibc.git synced 2024-11-25 06:20:06 +00:00
Code Issues Packages Projects Releases Wiki Activity
38,990 Commits 334 Branches 1,646 Tags 277 MiB
afc6e4328f
Commit Graph

398 Commits

Author SHA1 Message Date
Noah Goldstein
afc6e4328f x86: Put wcs{n}len-sse4.1 in the sse4.1 text section 
Previously was missing but the two implementations shouldn't get in
the sse2 (generic) text section.
 2022-06-27 08:35:51 -07:00
Noah Goldstein
227afaa672 x86: Align entry for memrchr to 64-bytes. 
The function was tuned around 64-byte entry alignment and performs
better for all sizes with it.

As well different code boths where explicitly written to touch the
minimum number of cache line i.e sizes <= 32 touch only the entry
cache line.
 2022-06-27 08:35:51 -07:00
Noah Goldstein
3079f652d7 x86: Replace all sse instructions with vex equivilent in avx+ files 
Most of these don't really matter as there was no dirty upper state
but we should generally avoid stray sse when its not needed.

The one case that really matters is in svml_d_tanh4_core_avx2.S:

blendvps %xmm0, %xmm8, %xmm7

When there was a dirty upper state.

Tested on x86_64-linux
 2022-06-22 19:42:17 -07:00
Noah Goldstein
3edda6a0f0 x86: Add support for compiling {raw|w}memchr with high ISA level 
1. Refactor files so that all implementations for in the multiarch
   directory.
    - Essentially moved sse2 {raw|w}memchr.S implementation to
      multiarch/{raw|w}memchr-sse2.S

    - The non-multiarch {raw|w}memchr.S file now only includes one of
      the implementations in the multiarch directory based on the
      compiled ISA level (only used for non-multiarch builds.
      Otherwise we go through the ifunc selector).

2. Add ISA level build guards to different implementations.
    - I.e memchr-avx2.S which is ISA level 3 will only build if
      compiled ISA level <= 3. Otherwise there is no reason to include
      it as we will always use one of the ISA level 4
      implementations (memchr-evex{-rtm}.S).

3. Add new multiarch/rtld-{raw}memchr.S that just include the
   non-multiarch {raw}memchr.S which will in turn select the best
   implementation based on the compiled ISA level.

4. Refactor the ifunc selector and ifunc implementation list to use
   the ISA level aware wrapper macros that allow functions below the
   compiled ISA level (with a guranteed replacement) to be skipped.
    - Guranteed replacement essentially means that for any ISA level
      build there must be a function that the baseline of the ISA
      supports. So for {raw|w}memchr.S since there is not ISA level 2
      function, the ISA level 2 build still includes the ISA level
      1 (sse2) function. Once we reach the ISA level 3 build, however,
      {raw|w}memchr-avx2{-rtm}.S will always be sufficient so the ISA
      level 1 implementation ({raw|w}memchr-sse2.S) will not be built.

Tested with and without multiarch on x86_64 for ISA levels:
{generic, x86-64-v2, x86-64-v3, x86-64-v4}

And m32 with and without multiarch.
 2022-06-22 19:41:35 -07:00
Noah Goldstein
c22eb807b0 x86: Rename generic functions with unique postfix for clarity 
No functions are changed. It just renames generic implementations from
'{func}_sse2' to '{func}_generic'. This is just because the postfix
"_sse2" was overloaded and was used for files that had hand-optimized
sse2 assembly implementations and files that just redirected back
to the generic implementation.

Full xcheck passed on x86_64.
 2022-06-16 20:17:45 -07:00
Noah Goldstein
89a25c6f64 x86: Cleanup bounds checking in large memcpy case 
1. Fix incorrect lower-bound threshold in L(large_memcpy_2x).
   Previously was using `__x86_rep_movsb_threshold` and should
   have been using `__x86_shared_non_temporal_threshold`.

2. Avoid reloading __x86_shared_non_temporal_threshold before
   the L(large_memcpy_4x) bounds check.

3. Document the second bounds check for L(large_memcpy_4x)
   more clearly.
 2022-06-15 14:25:55 -07:00
Noah Goldstein
ff439c4717 x86: Add sse42 implementation to strcmp's ifunc 
This has been missing since the the ifuncs where added.

The performance of SSE4.2 is preferable to to SSE2.

Measured on Tigerlake with N = 20 runs.
Geometric Mean of all benchmarks SSE4.2 / SSE2: 0.906
 2022-06-14 20:58:09 -07:00
Wilco Dijkstra
fdaf78656f Add bounds check to __libc_ifunc_impl_list 
Add a proper bounds check to __libc_ifunc_impl_list. This makes MAX_IFUNC
redundant and fixes several targets that will write outside the array.
To avoid unnecessary large diffs, pass the maximum in the argument 'i' to
IFUNC_IMPL_ADD - 'max' can be used in new ifunc definitions and existing
ones can be updated if desired.

Passes buildmanyglibc.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 2022-06-10 17:13:29 +01:00
Noah Goldstein
0f91811333 x86: Align varshift table to 32-bytes 
This ensures the load will never split a cache line.
 2022-06-09 12:50:26 -07:00
Noah Goldstein
4654e7fd5a x86: Add copyright to strpbrk-c.c 2022-06-09 12:50:00 -07:00
Noah Goldstein
2c9af8421d x86: Fix page cross case in rawmemchr-avx2 [BZ #29234] 
commit 6dcbb7d95d
Author: Noah Goldstein <goldstein.w.n@gmail.com>
Date:   Mon Jun 6 21:11:33 2022 -0700

    x86: Shrink code size of memchr-avx2.S

Changed how the page cross case aligned string (rdi) in
rawmemchr. This was incompatible with how
`L(cross_page_continue)` expected the pointer to be aligned and
would cause rawmemchr to read data start started before the
beginning of the string. What it would read was in valid memory
but could count CHAR matches resulting in an incorrect return
value.

This commit fixes that issue by essentially reverting the changes to
the L(page_cross) case as they didn't really matter.

Test cases added and all pass with the new code (and where confirmed
to fail with the old code).
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-06-08 17:07:34 -07:00
Noah Goldstein
56da3fe1dd x86: Shrink code size of memchr-evex.S 
This is not meant as a performance optimization. The previous code was
far to liberal in aligning targets and wasted code size unnecissarily.

The total code size saving is: 64 bytes

There are no non-negligible changes in the benchmarks.
Geometric Mean of all benchmarks New / Old: 1.000

Full xcheck passes on x86_64.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-06-07 13:10:32 -07:00
Noah Goldstein
6dcbb7d95d x86: Shrink code size of memchr-avx2.S 
This is not meant as a performance optimization. The previous code was
far to liberal in aligning targets and wasted code size unnecissarily.

The total code size saving is: 59 bytes

There are no major changes in the benchmarks.
Geometric Mean of all benchmarks New / Old: 0.967

Full xcheck passes on x86_64.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-06-07 13:10:31 -07:00
Noah Goldstein
af5306a735 x86: Optimize memrchr-avx2.S 
The new code:
    1. prioritizes smaller user-arg lengths more.
    2. optimizes target placement more carefully
    3. reuses logic more
    4. fixes up various inefficiencies in the logic. The biggest
       case here is the `lzcnt` logic for checking returns which
       saves either a branch or multiple instructions.

The total code size saving is: 306 bytes
Geometric Mean of all benchmarks New / Old: 0.760

Regressions:
There are some regressions. Particularly where the length (user arg
length) is large but the position of the match char is near the
beginning of the string (in first VEC). This case has roughly a
10-20% regression.

This is because the new logic gives the hot path for immediate matches
to shorter lengths (the more common input). This case has roughly
a 15-45% speedup.

Full xcheck passes on x86_64.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-06-07 13:10:27 -07:00
Noah Goldstein
b4209615a0 x86: Optimize memrchr-evex.S 
The new code:
    1. prioritizes smaller user-arg lengths more.
    2. optimizes target placement more carefully
    3. reuses logic more
    4. fixes up various inefficiencies in the logic. The biggest
       case here is the `lzcnt` logic for checking returns which
       saves either a branch or multiple instructions.

The total code size saving is: 263 bytes
Geometric Mean of all benchmarks New / Old: 0.755

Regressions:
There are some regressions. Particularly where the length (user arg
length) is large but the position of the match char is near the
beginning of the string (in first VEC). This case has roughly a
20% regression.

This is because the new logic gives the hot path for immediate matches
to shorter lengths (the more common input). This case has roughly
a 35% speedup.

Full xcheck passes on x86_64.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-06-07 13:10:24 -07:00
Noah Goldstein
dd5c483b25 x86: Add COND_VZEROUPPER that can replace vzeroupper if no ret 
The RTM vzeroupper mitigation has no way of replacing inline
vzeroupper not before a return.

This can be useful when hoisting a vzeroupper to save code size
for example:

```
L(foo):
	cmpl	%eax, %edx
	jz	L(bar)
	tzcntl	%eax, %eax
	addq	%rdi, %rax
	VZEROUPPER_RETURN

L(bar):
	xorl	%eax, %eax
	VZEROUPPER_RETURN
```

Can become:

```
L(foo):
	COND_VZEROUPPER
	cmpl	%eax, %edx
	jz	L(bar)
	tzcntl	%eax, %eax
	addq	%rdi, %rax
	ret

L(bar):
	xorl	%eax, %eax
	ret
```

This code does not change any existing functionality.

There is no difference in the objdump of libc.so before and after this
patch.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-06-07 13:08:28 -07:00
Noah Goldstein
8a780a6b91 x86: Create header for VEC classes in x86 strings library 
This patch does not touch any existing code and is only meant to be a
tool for future patches so that simple source files can more easily be
maintained to target multiple VEC classes.

There is no difference in the objdump of libc.so before and after this
patch.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-06-07 13:08:28 -07:00
Raghuveer Devulapalli
5082a287d5 x86_64: Add strstr function with 512-bit EVEX 
Adding a 512-bit EVEX version of strstr. The algorithm works as follows:

(1) We spend a few cycles at the begining to peek into the needle. We
locate an edge in the needle (first occurance of 2 consequent distinct
characters) and also store the first 64-bytes into a zmm register.

(2) We search for the edge in the haystack by looking into one cache
line of the haystack at a time. This avoids having to read past a page
boundary which can cause a seg fault.

(3) If an edge is found in the haystack we first compare the first
64-bytes of the needle (already stored in a zmm register) before we
proceed with a full string compare performed byte by byte.

Benchmarking results: (old = strstr_sse2_unaligned, new = strstr_avx512)

Geometric mean of all benchmarks: new / old =  0.66

Difficult skiptable(0) : new / old =  0.02
Difficult skiptable(1) : new / old =  0.01
Difficult 2-way : new / old =  0.25
Difficult testing first 2 : new / old =  1.26
Difficult skiptable(0) : new / old =  0.05
Difficult skiptable(1) : new / old =  0.06
Difficult 2-way : new / old =  0.26
Difficult testing first 2 : new / old =  1.05
Difficult skiptable(0) : new / old =  0.42
Difficult skiptable(1) : new / old =  0.24
Difficult 2-way : new / old =  0.21
Difficult testing first 2 : new / old =  1.04
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-06-06 19:46:55 -07:00
Sunil K Pandey
9c66efb86f x86_64: Implement evex512 version of strlen, strnlen, wcslen and wcsnlen 
This patch implements following evex512 version of string functions.
Perf gain for evex512 version is up to 50% as compared to evex,
depending on length and alignment.

Placeholder function, not used by any processor at the moment.

- String length function using 512 bit vectors.
- String N length using 512 bit vectors.
- Wide string length using 512 bit vectors.
- Wide string N length using 512 bit vectors.

Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
 2022-05-26 13:11:36 -07:00
Adhemerval Zanella
9403b71ae9 x86_64: Remove bzero optimization 
Both symbols are marked as legacy in POSIX.1-2001 and removed on
POSIX.1-2008, although the prototypes are defined for _GNU_SOURCE
or _DEFAULT_SOURCE.

GCC also replaces bcopy with a memmove and bzero with memset on default
configuration (to actually get a bzero libc call the code requires
to omit string.h inclusion and built with -fno-builtin), so it is
highly unlikely programs are actually calling libc bzero symbol.

On a recent Linux distro (Ubuntu 22.04), there is no bzero calls
by the installed binaries.

  $ cat count_bstring.sh
  #!/bin/bash

  files=`IFS=':';for i in $PATH; do test -d "$i" && find "$i" -maxdepth 1 -executable -type f; done`
  total=0
  for file in $files; do
    symbols=`objdump -R $file 2>&1`
    if [ $? -eq 0 ]; then
      ncalls=`echo $symbols | grep -w $1 | wc -l`
      ((total=total+ncalls))
      if [ $ncalls -gt 0 ]; then
        echo "$file: $ncalls"
      fi
    fi
  done
  echo "TOTAL=$total"
  $ ./count_bstring.sh bzero
  TOTAL=0

Checked on x86_64-linux-gnu.
 2022-05-16 09:36:06 -03:00
Noah Goldstein
c966099cdc x86: Optimize {str|wcs}rchr-evex 
The new code unrolls the main loop slightly without adding too much
overhead and minimizes the comparisons for the search CHAR.

Geometric Mean of all benchmarks New / Old: 0.755
See email for all results.

Full xcheck passes on x86_64 with and without multiarch enabled.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-04-22 23:08:43 -05:00
Noah Goldstein
df7e295d18 x86: Optimize {str|wcs}rchr-avx2 
The new code unrolls the main loop slightly without adding too much
overhead and minimizes the comparisons for the search CHAR.

Geometric Mean of all benchmarks New / Old: 0.832
See email for all results.

Full xcheck passes on x86_64 with and without multiarch enabled.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-04-22 23:08:40 -05:00
Noah Goldstein
5307aa9c18 x86: Optimize {str|wcs}rchr-sse2 
The new code unrolls the main loop slightly without adding too much
overhead and minimizes the comparisons for the search CHAR.

Geometric Mean of all benchmarks New / Old: 0.741
See email for all results.

Full xcheck passes on x86_64 with and without multiarch enabled.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-04-22 23:08:36 -05:00
H.J. Lu
8ea20ee5f6 x86-64: Fix SSE2 memcmp and SSSE3 memmove for x32 
Clear the upper 32 bits in RDX (memory size) for x32 to fix

FAIL: string/tst-size_t-memcmp
FAIL: string/tst-size_t-memcmp-2
FAIL: string/tst-size_t-memcpy
FAIL: wcsmbs/tst-size_t-wmemcmp

on x32 introduced by

8804157ad9 x86: Optimize memcmp SSE2 in memcmp.S
26b2478322 x86: Reduce code size of mem{move|pcpy|cpy}-ssse3

Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
 2022-04-22 11:23:15 -07:00
Noah Goldstein
c72a1a062a x86: Fix missing __wmemcmp def for disable-multiarch build 
commit 8804157ad9
Author: Noah Goldstein <goldstein.w.n@gmail.com>
Date:   Fri Apr 15 12:27:59 2022 -0500

    x86: Optimize memcmp SSE2 in memcmp.S

Only defined wmemcmp and missed __wmemcmp. This commit fixes that by
defining __wmemcmp and setting wmemcmp as a weak alias to __wmemcmp.

Both multiarch and disable-multiarch builds succeed and full xchecks
pass.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-04-19 20:18:57 -05:00
Noah Goldstein
23102686ec x86: Cleanup page cross code in memcmp-avx2-movbe.S 
Old code was both inefficient and wasted code size. New code (-62
bytes) and comparable or better performance in the page cross case.

geometric_mean(N=20) of page cross cases New / Original: 0.960

size, align0, align1, ret, New Time/Old Time
   1,   4095,      0,   0,             1.001
   1,   4095,      0,   1,             0.999
   1,   4095,      0,  -1,               1.0
   2,   4094,      0,   0,               1.0
   2,   4094,      0,   1,               1.0
   2,   4094,      0,  -1,               1.0
   3,   4093,      0,   0,               1.0
   3,   4093,      0,   1,               1.0
   3,   4093,      0,  -1,               1.0
   4,   4092,      0,   0,             0.987
   4,   4092,      0,   1,               1.0
   4,   4092,      0,  -1,               1.0
   5,   4091,      0,   0,             0.984
   5,   4091,      0,   1,             1.002
   5,   4091,      0,  -1,             1.005
   6,   4090,      0,   0,             0.993
   6,   4090,      0,   1,             1.001
   6,   4090,      0,  -1,             1.003
   7,   4089,      0,   0,             0.991
   7,   4089,      0,   1,               1.0
   7,   4089,      0,  -1,             1.001
   8,   4088,      0,   0,             0.875
   8,   4088,      0,   1,             0.881
   8,   4088,      0,  -1,             0.888
   9,   4087,      0,   0,             0.872
   9,   4087,      0,   1,             0.879
   9,   4087,      0,  -1,             0.883
  10,   4086,      0,   0,             0.878
  10,   4086,      0,   1,             0.886
  10,   4086,      0,  -1,             0.873
  11,   4085,      0,   0,             0.878
  11,   4085,      0,   1,             0.881
  11,   4085,      0,  -1,             0.879
  12,   4084,      0,   0,             0.873
  12,   4084,      0,   1,             0.889
  12,   4084,      0,  -1,             0.875
  13,   4083,      0,   0,             0.873
  13,   4083,      0,   1,             0.863
  13,   4083,      0,  -1,             0.863
  14,   4082,      0,   0,             0.838
  14,   4082,      0,   1,             0.869
  14,   4082,      0,  -1,             0.877
  15,   4081,      0,   0,             0.841
  15,   4081,      0,   1,             0.869
  15,   4081,      0,  -1,             0.876
  16,   4080,      0,   0,             0.988
  16,   4080,      0,   1,              0.99
  16,   4080,      0,  -1,             0.989
  17,   4079,      0,   0,             0.978
  17,   4079,      0,   1,             0.981
  17,   4079,      0,  -1,              0.98
  18,   4078,      0,   0,             0.981
  18,   4078,      0,   1,              0.98
  18,   4078,      0,  -1,             0.985
  19,   4077,      0,   0,             0.977
  19,   4077,      0,   1,             0.979
  19,   4077,      0,  -1,             0.986
  20,   4076,      0,   0,             0.977
  20,   4076,      0,   1,             0.986
  20,   4076,      0,  -1,             0.984
  21,   4075,      0,   0,             0.977
  21,   4075,      0,   1,             0.983
  21,   4075,      0,  -1,             0.988
  22,   4074,      0,   0,             0.983
  22,   4074,      0,   1,             0.994
  22,   4074,      0,  -1,             0.993
  23,   4073,      0,   0,              0.98
  23,   4073,      0,   1,             0.992
  23,   4073,      0,  -1,             0.995
  24,   4072,      0,   0,             0.989
  24,   4072,      0,   1,             0.989
  24,   4072,      0,  -1,             0.991
  25,   4071,      0,   0,              0.99
  25,   4071,      0,   1,             0.999
  25,   4071,      0,  -1,             0.996
  26,   4070,      0,   0,             0.993
  26,   4070,      0,   1,             0.995
  26,   4070,      0,  -1,             0.998
  27,   4069,      0,   0,             0.993
  27,   4069,      0,   1,             0.999
  27,   4069,      0,  -1,               1.0
  28,   4068,      0,   0,             0.997
  28,   4068,      0,   1,               1.0
  28,   4068,      0,  -1,             0.999
  29,   4067,      0,   0,             0.996
  29,   4067,      0,   1,             0.999
  29,   4067,      0,  -1,             0.999
  30,   4066,      0,   0,             0.991
  30,   4066,      0,   1,             1.001
  30,   4066,      0,  -1,             0.999
  31,   4065,      0,   0,             0.988
  31,   4065,      0,   1,             0.998
  31,   4065,      0,  -1,             0.998
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-04-15 13:08:52 -05:00
Noah Goldstein
7cbc03d030 x86: Remove memcmp-sse4.S 
Code didn't actually use any sse4 instructions since `ptest` was
removed in:

commit 2f9062d717
Author: Noah Goldstein <goldstein.w.n@gmail.com>
Date:   Wed Nov 10 16:18:56 2021 -0600

    x86: Shrink memcmp-sse4.S code size

The new memcmp-sse2 implementation is also faster.

geometric_mean(N=20) of page cross cases SSE2 / SSE4: 0.905

Note there are two regressions preferring SSE2 for Size = 1 and Size =
65.

Size = 1:
size, align0, align1, ret, New Time/Old Time
   1,      1,      1,   0,               1.2
   1,      1,      1,   1,             1.197
   1,      1,      1,  -1,               1.2

This is intentional. Size == 1 is significantly less hot based on
profiles of GCC11 and Python3 than sizes [4, 8] (which is made
hotter).

Python3 Size = 1        -> 13.64%
Python3 Size = [4, 8]   -> 60.92%

GCC11   Size = 1        ->  1.29%
GCC11   Size = [4, 8]   -> 33.86%

size, align0, align1, ret, New Time/Old Time
   4,      4,      4,   0,             0.622
   4,      4,      4,   1,             0.797
   4,      4,      4,  -1,             0.805
   5,      5,      5,   0,             0.623
   5,      5,      5,   1,             0.777
   5,      5,      5,  -1,             0.802
   6,      6,      6,   0,             0.625
   6,      6,      6,   1,             0.813
   6,      6,      6,  -1,             0.788
   7,      7,      7,   0,             0.625
   7,      7,      7,   1,             0.799
   7,      7,      7,  -1,             0.795
   8,      8,      8,   0,             0.625
   8,      8,      8,   1,             0.848
   8,      8,      8,  -1,             0.914
   9,      9,      9,   0,             0.625

Size = 65:
size, align0, align1, ret, New Time/Old Time
  65,      0,      0,   0,             1.103
  65,      0,      0,   1,             1.216
  65,      0,      0,  -1,             1.227
  65,     65,      0,   0,             1.091
  65,      0,     65,   1,              1.19
  65,     65,     65,  -1,             1.215

This is because A) the checks in range [65, 96] are now unrolled 2x
and B) because smaller values <= 16 are now given a hotter path. By
contrast the SSE4 version has a branch for Size = 80. The unrolled
version has get better performance for returns which need both
comparisons.

size, align0, align1, ret, New Time/Old Time
 128,      4,      8,   0,             0.858
 128,      4,      8,   1,             0.879
 128,      4,      8,  -1,             0.888

As well, out of microbenchmark environments that are not full
predictable the branch will have a real-cost.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-04-15 13:08:42 -05:00
Noah Goldstein
8804157ad9 x86: Optimize memcmp SSE2 in memcmp.S 
New code save size (-303 bytes) and has significantly better
performance.

geometric_mean(N=20) of page cross cases New / Original: 0.634
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-04-15 13:08:35 -05:00
Noah Goldstein
26b2478322 x86: Reduce code size of mem{move|pcpy|cpy}-ssse3 
The goal is to remove most SSSE3 function as SSE4, AVX2, and EVEX are
generally preferable. memcpy/memmove is one exception where avoiding
unaligned loads with `palignr` is important for some targets.

This commit replaces memmove-ssse3 with a better optimized are lower
code footprint verion. As well it aliases memcpy to memmove.

Aside from this function all other SSSE3 functions should be safe to
remove.

The performance is not changed drastically although shows overall
improvements without any major regressions or gains.

bench-memcpy geometric_mean(N=50) New / Original: 0.957

bench-memcpy-random geometric_mean(N=50) New / Original: 0.912

bench-memcpy-large geometric_mean(N=50) New / Original: 0.892

Benchmarks where run on Zhaoxin KX-6840@2000MHz See attached numbers
for all results.

More important this saves 7246 bytes of code size in memmove an
additional 10741 bytes by reusing memmove code for memcpy (total 17987
bytes saves). As well an additional 896 bytes of rodata for the jump
table entries.
 2022-04-14 23:21:42 -05:00
Noah Goldstein
d85916e30a x86: Remove mem{move|cpy}-ssse3-back 
With SSE2, SSE4.1, AVX2, and EVEX versions very few targets prefer
SSSE3. As a result it is no longer worth it to keep the SSSE3
versions given the code size cost.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-04-14 23:21:42 -05:00
Noah Goldstein
41bfe224e5 x86: Remove str{p}{n}cpy-ssse3 
With SSE2, SSE4.1, AVX2, and EVEX versions very few targets prefer
SSSE3. As a result it is no longer worth it to keep the SSSE3
versions given the code size cost.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-04-14 23:21:42 -05:00
Noah Goldstein
e084ccd37e x86: Remove str{n}cat-ssse3 
With SSE2, SSE4.1, AVX2, and EVEX versions very few targets prefer
SSSE3. As a result it is no longer worth it to keep the SSSE3
versions given the code size cost.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-04-14 23:21:41 -05:00
Noah Goldstein
c024a0b9cf x86: Remove str{n}{case}cmp-ssse3 
With SSE2, SSE4.1, AVX2, and EVEX versions very few targets prefer
SSSE3. As a result it is no longer worth it to keep the SSSE3
versions given the code size cost.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-04-14 23:21:41 -05:00
Noah Goldstein
c725f408db x86: Remove {w}memcmp-ssse3 
With SSE2, SSE4.1, AVX2, and EVEX versions very few targets prefer
SSSE3. As a result it is no longer worth it to keep the SSSE3
versions given the code size cost.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-04-14 23:21:41 -05:00
Noah Goldstein
f5bff979d0 x86: Small improvements for wcscpy-ssse3 
Just a few small QOL changes.
    1. Prefer `add` > `lea` as it has high execution units it can run
       on.
    2. Don't break macro-fusion between `test` and `jcc`

geometric_mean(N=20) of all benchmarks New / Original: 0.973

All string/memory tests pass.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-03-28 15:00:03 -05:00
Noah Goldstein
305769b2a1 x86: Remove AVX str{n}casecmp 
The rational is:

1. SSE42 has nearly identical logic so any benefit is minimal (3.4%
   regression on Tigerlake using SSE42 versus AVX across the
   benchtest suite).
2. AVX2 version covers the majority of targets that previously
   prefered it.
3. The targets where AVX would still be best (SnB and IVB) are
   becoming outdated.

All in all the saving the code size is worth it.

All string/memory tests pass.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-03-25 13:16:51 -05:00
Noah Goldstein
84e7c46df4 x86: Add EVEX optimized str{n}casecmp 
geometric_mean(N=40) of all benchmarks EVEX / SSE42: .621

All string/memory tests pass.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-03-25 13:16:50 -05:00
Noah Goldstein
bbf8122234 x86: Add AVX2 optimized str{n}casecmp 
geometric_mean(N=40) of all benchmarks AVX2 / SSE42: .702

All string/memory tests pass.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-03-25 13:16:43 -05:00
Noah Goldstein
d154758e61 x86: Optimize str{n}casecmp TOLOWER logic in strcmp-sse42.S 
Slightly faster method of doing TOLOWER that saves an
instruction.

Also replace the hard coded 5-byte no with .p2align 4. On builds with
CET enabled this misaligned entry to strcasecmp.

geometric_mean(N=40) of all benchmarks New / Original: .920

All string/memory tests pass.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-03-25 11:46:13 -05:00
Noah Goldstein
9fef7039a7 x86: Fix fallback for wcsncmp_avx2 in strcmp-avx2.S [BZ #28896] 
Overflow case for __wcsncmp_avx2_rtm should be __wcscmp_avx2_rtm not
__wcscmp_avx2.

commit ddf0992cf5
Author: Noah Goldstein <goldstein.w.n@gmail.com>
Date:   Sun Jan 9 16:02:21 2022 -0600

    x86: Fix __wcsncmp_avx2 in strcmp-avx2.S [BZ# 28755]

Set the wrong fallback function for `__wcsncmp_avx2_rtm`. It was set
to fallback on to `__wcscmp_avx2` instead of `__wcscmp_avx2_rtm` which
can cause spurious aborts.

This change will need to be backported.

All string/memory tests pass.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-03-25 11:46:13 -05:00
Noah Goldstein
9c8a6ad620 x86: Remove strspn-sse2.S and use the generic implementation 
The generic implementation is faster.

geometric_mean(N=20) of all benchmarks New / Original: .710

All string/memory tests pass.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-03-25 11:46:13 -05:00
Noah Goldstein
6533585352 x86: Remove strpbrk-sse2.S and use the generic implementation 
The generic implementation is faster (see strcspn commit).

All string/memory tests pass.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-03-25 11:46:13 -05:00
Noah Goldstein
fe28e7d9d9 x86: Remove strcspn-sse2.S and use the generic implementation 
The generic implementation is faster.

geometric_mean(N=20) of all benchmarks New / Original: .678

All string/memory tests pass.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-03-25 11:46:13 -05:00
Noah Goldstein
412d103431 x86: Optimize strspn in strspn-c.c 
Use _mm_cmpeq_epi8 and _mm_movemask_epi8 to get strlen instead of
_mm_cmpistri. Also change offset to unsigned to avoid unnecessary
sign extensions.

geometric_mean(N=20) of all benchmarks that dont fallback on
sse2; New / Original: .901

All string/memory tests pass.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-03-25 11:46:13 -05:00
Noah Goldstein
30d627d477 x86: Optimize strcspn and strpbrk in strcspn-c.c 
Use _mm_cmpeq_epi8 and _mm_movemask_epi8 to get strlen instead of
_mm_cmpistri. Also change offset to unsigned to avoid unnecessary
sign extensions.

geometric_mean(N=20) of all benchmarks that dont fallback on
sse2/strlen; New / Original: .928

All string/memory tests pass.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-03-25 11:46:13 -05:00
Noah Goldstein
ec285ea904 x86: Code cleanup in strchr-evex and comment justifying branch 
Small code cleanup for size: -81 bytes.

Add comment justifying using a branch to do NULL/non-null return.

All string/memory tests pass and no regressions in benchtests.

geometric_mean(N=20) of all benchmarks New / Original: .985
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-03-25 11:46:13 -05:00
Noah Goldstein
a6fbf4d51e x86: Code cleanup in strchr-avx2 and comment justifying branch 
Small code cleanup for size: -53 bytes.

Add comment justifying using a branch to do NULL/non-null return.

All string/memory tests pass and no regressions in benchtests.

geometric_mean(N=20) of all benchmarks Original / New: 1.00
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-03-25 11:46:13 -05:00
Adhemerval Zanella
bf92893a14 x86_64: Remove bcopy optimizations 
The symbols is not present in current POSIX specification and compiler
already generates memmove call.
 2022-02-23 14:06:49 -03:00
Noah Goldstein
c627209832 x86: Fallback {str|wcs}cmp RTM in the ncmp overflow case [BZ #28896] 
In the overflow fallback strncmp-avx2-rtm and wcsncmp-avx2-rtm would
call strcmp-avx2 and wcscmp-avx2 respectively. This would have
not checks around vzeroupper and would trigger spurious
aborts. This commit fixes that.

test-strcmp, test-strncmp, test-wcscmp, and test-wcsncmp all pass on
AVX2 machines with and without RTM.

Co-authored-by: H.J. Lu <hjl.tools@gmail.com>
 2022-02-17 15:43:05 -06:00
Noah Goldstein
e108c02a5e x86: Fix bug in strncmp-evex and strncmp-avx2 [BZ #28895] 
Logic can read before the start of `s1` / `s2` if both `s1` and `s2`
are near the start of a page. To avoid having the result contimated by
these comparisons the `strcmp` variants would mask off these
comparisons. This was missing in the `strncmp` variants causing
the bug. This commit adds the masking to `strncmp` so that out of
range comparisons don't affect the result.

test-strcmp, test-strncmp, test-wcscmp, and test-wcsncmp all pass as
well a full xcheck on x86_64 linux.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
 2022-02-16 02:11:16 -06:00