Commit Graph

39378 Commits

Author SHA1 Message Date
H.J. Lu
bbff275fb1 elf: Build tst-relr-mod[34]a.so with $(LDFLAGS-rpath-ORIGIN)
When --enable-hardcoded-path-in-tests is used only with DT_RUNPATH,
elf/tst-relr3 and elf/tst-relr4 failed to run.  Their dependency
libraries, tst-relr-mod3a.so and tst-relr-mod4a.so, are failed to
load since DT_RUNPATH on executable doesn't apply to them.  Build
tst-relr-mod3a.so and tst-relr-mod4a.so with $(LDFLAGS-rpath-ORIGIN)
to add DT_RUNPATH for their dependency libraries.
Reviewed-by: Fangrui Song <maskray@google.com>
2022-10-31 09:00:26 -07:00
Sunil K Pandey
e96971482d x86-64: Improve evex512 version of strlen functions
This patch improves following functionality
- Replace VPCMP with VPCMPEQ.
- Replace page cross check logic with sall.
- Remove extra lea from align_more.
- Remove uncondition loop jump.
- Use bsf to check max length in first vector.

Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2022-10-30 13:09:56 -07:00
Ludovic Courtès
361d6454c0 Correctly determine libc.so 'OUTPUT_FORMAT' when cross-compiling.
Commit 87d583c6e8 replaces the sed script
with an "objdump -f" invocation to determine the 'OUTPUT_FORMAT' bit of
the libc.so linker script.

However, when cross-compiling, for example from x86_64-linux-gnu to
aarch64-linux-gnu, "objdump -f" would report the wrong
format ("elf64-little").  Conversely, "aarch64-linux-gnu-objdump -f"
reports "elf64-littleaarch64" as expected.

This patch changes 'configure.ac' to use AC_CHECK_TOOL rather than
'$CC -print-prog-name=objdump' to determine the value of the OBJDUMP
variable.  That way, OBJDUMP is set to TRIPLET-objdump when
cross-compiling for TRIPLET.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
2022-10-28 17:19:02 -04:00
Szabolcs Nagy
8c77e26ba8 Remove unused scratch_buffer_dupfree
Turns out scratch_buffer_dupfree internal API was unused since

commit ef0700004b
stdlib: Simplify buffer management in canonicalize

And the related test in malloc/tst-scratch_buffer had issues
so it's better to remove it completely.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2022-10-28 18:43:58 +01:00
Szabolcs Nagy
2eeeee7636 Fix elf/tst-dlmopen-twice not to exhaust static TLS
By default glibc only allocates enough static TLS for 4 link namespaces
including the initial one. So only use 3 dlmopens in the test.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2022-10-28 18:43:58 +01:00
Szabolcs Nagy
f9deea6f81 Use uintptr_t in string/tester for pointer alignment
The code assumed unsigned long can represent pointers.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2022-10-28 17:31:57 +01:00
Letu Ren
0cc0033ef1 stdlib/strfrom: Add copysign to fix NAN issue on riscv (BZ #29501)
According to the specification of ISO/IEC TS 18661-1:2014,

The strfromd, strfromf, and strfroml functions are equivalent to
snprintf(s, n, format, fp) (7.21.6.5), except the format string contains only
the character %, an optional precision that does not contain an asterisk *, and
one of the conversion specifiers a, A, e, E, f, F, g, or G, which applies to
the type (double, float, or long double) indicated by the function suffix
(rather than  by a length modifier). Use of these functions with any other 20
format string results in undefined behavior.

strfromf will convert the arguement with type float to double first.

According to the latest version of IEEE754 which is published in 2019,

Conversion of a quiet NaN from a narrower format to a wider format in the same
radix, and then back to the same narrower format, should not change the quiet
NaN payload in any way except to make it canonical.

When either an input or result is a NaN, this standard does not interpret the
sign of a NaN. However, operations on bit strings—copy, negate, abs,
copySign—specify the sign bit of a NaN result, sometimes based upon the sign
bit of a NaN operand. The logical predicates totalOrder and isSignMinus are
also affected by the sign bit of a NaN operand. For all other operations, this
standard does not specify the sign bit of a NaN result, even when there is only
one input NaN, or when the NaN is produced from an invalid operation.

converting NAN or -NAN with type float to double doesn't need to keep
the signbit. As a result, this test case isn't mandatory.

The problem is that according to RISC-V ISA manual in chapter 11.3 of
riscv-isa-20191213,

Except when otherwise stated, if the result of a floating-point operation is
NaN, it is the canonical NaN. The canonical NaN has a positive sign and all
significand bits clear except the MSB, a.k.a. the quiet bit. For
single-precision floating-point, this corresponds to the pattern 0x7fc00000.

which means that conversion -NAN from float to double won't keep the signbit.

Since glibc ought to be consistent here between types and architectures, this
patch adds copysign to fix this problem if the string is NAN. This patch
adds two different functions under sysdeps directory to work around the
issue.

This patch has been tested on x86_64 and riscv64.

Resolves: BZ #29501

v2: Change from macros to different inline functions.
v3: Add unlikely check to isnan.
v4: Fix wrong commit message header.
v5: Fix style: add space before parentheses.
v6: Add copyright.
Signed-off-by: Letu Ren <fantasquex@gmail.com>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2022-10-28 11:35:20 -03:00
Szabolcs Nagy
b4174c28d2 Fix resource/bug-ulimit1 test
ulimit is a variadic function and the second argument must have type
long (or unsigned long).

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2022-10-28 11:17:18 +01:00
Szabolcs Nagy
b866018f54 Fix missing NUL terminator in stdio-common/scanf13 test
sscanf is only defined on nul terminated string input, but '\0' was
missing in this test which caused _IO_str_init_static_internal to
read OOB on the stack when computing the bounds of the string.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2022-10-28 11:16:51 +01:00
Szabolcs Nagy
6a3794ea91 Fix off-by-one OOB read in elf/tst-tls20
The int mods[nmods] array on the stack was overread by one.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2022-10-28 11:16:51 +01:00
Szabolcs Nagy
eef17d4d9f elf: Fix alloca size in _dl_debug_vdprintf
The alloca size did not consider the optional width parameter for
padding which could cause buffer underflow. The width is currently used
e.g. by _dl_map_object_from_fd which passes 2 * sizeof(void *) which
can be larger than the alloca buffer size on targets where
sizeof(void *) >= 2 * sizeof(unsigned long).

Even if large width is not used on existing targets it is better to fix
the formatting code to avoid surprises.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2022-10-28 11:16:09 +01:00
Szabolcs Nagy
68619ddb3b malloc: Use uintptr_t in alloc_buffer
The values represnt pointers and not sizes. The members of struct
alloc_buffer are already uintptr_t.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2022-10-28 11:16:09 +01:00
Szabolcs Nagy
3fa20d59d9 Fix invalid pointer dereference in wcpcpy_chk
The src pointer is const and points to a different object, so accessing
dest via src is invalid.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2022-10-28 11:15:28 +01:00
Szabolcs Nagy
e5ece9de14 Fix invalid pointer dereference in wcscpy_chk
The src pointer is const and points to a different object, so accessing
dest via src is invalid.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2022-10-28 11:15:28 +01:00
Szabolcs Nagy
09c6c6073c aarch64: Fix the extension header write in getcontext and swapcontext
The extension header is two 32bit words and in the last header both
should be 0. There is plenty space in the __reserved area, but it's
better not to write more than we mean to.
2022-10-28 11:14:54 +01:00
Szabolcs Nagy
dd31f42e39 aarch64: Don't build wordcopy
Use an empty wordcopy.c to avoid building the generic one.
It does not seem to be used anywhere.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2022-10-28 11:14:54 +01:00
Szabolcs Nagy
0b845d3b3f scripts: Use bool in tunables initializer
The initializer for a tunable_t set the bool initialized flag to NULL.
This causes a build failure when pointer to bool conversion warns.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2022-10-28 11:14:54 +01:00
Xi Ruoyao
37db2657c9 longlong.h: update from GCC for LoongArch clz/ctz support
Update longlong.h to GCC r13-3269.  Keep our local change (prefer https
for gnu.org URL).
2022-10-28 15:02:53 +08:00
Florian Weimer
6f360366f7 elf: Introduce to _dl_call_fini
This consolidates the destructor invocations from _dl_fini and
dlclose.  Remove the micro-optimization that avoids
calling _dl_call_fini if they are no destructors (as dlclose is quite
expensive anyway).  The debug log message is now printed
unconditionally.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2022-10-27 11:36:44 +02:00
Florian Weimer
a65ff76c9a ld.so: Export tls_init_tp_called as __rtld_tls_init_tp_called
This allows the rest of dynamic loader to check whether the TCB
has been set up (and THREAD_GETMEM and THREAD_SETMEM will work).

Reviewed-by: Siddhesh Poyarekar <siddhesh@gotplt.org>
2022-10-27 11:36:44 +02:00
Florian Weimer
77db67c56b scripts/localplt.awk: Handle DT_JMPREL with empty PLT (for C-SKY)
On csky-linux-gnuabiv2, binutils 2.33 produces a DT_JMPREL entry
for the dynamic loader if it does not contain any PLT relocations:

Dynamic section at offset 0x1df48 contains 19 entries:
  Tag        Type                         Name/Value
 0x0000000e (SONAME)                     Library soname: [ld-linux-cskyv2-hf.so.1]
 0x00000004 (HASH)                       0xd4
 0x6ffffef5 (GNU_HASH)                   0x1a8
 0x00000005 (STRTAB)                     0x4ac
 0x00000006 (SYMTAB)                     0x28c
 0x0000000a (STRSZ)                      527 (bytes)
 0x0000000b (SYMENT)                     16 (bytes)
 0x00000003 (PLTGOT)                     0x1f000
 0x00000002 (PLTRELSZ)                   0 (bytes)
 0x00000014 (PLTREL)                     RELA
 0x00000017 (JMPREL)                     0xaa4
 0x00000007 (RELA)                       0x75c
 0x00000008 (RELASZ)                     840 (bytes)
 0x00000009 (RELAENT)                    12 (bytes)
 0x6ffffffc (VERDEF)                     0x700
 0x6ffffffd (VERDEFNUM)                  3
 0x6ffffff0 (VERSYM)                     0x6bc
 0x6ffffff9 (RELACOUNT)                  68
 0x00000000 (NULL)                       0x0

This confuses the script:

Unexpected output from check-localplt: …/elf/ld.so.jmprel:
*** DT_JMPREL does not match any section's address

This commit changes the script to record the DT_PLTRELSZ value and
reject DT_JMPREL values not a section boundary only if DT_PLTRELSZ
is present with a non-zero value.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2022-10-27 11:36:44 +02:00
Adhemerval Zanella
11306df777 Remove lingering libSegfault Makefile entries
The library was removed by 65ccd641ba.
2022-10-26 15:55:43 -03:00
Wilco Dijkstra
e6f3fe362f aarch64: Use memcpy_simd as the default memcpy
Since __memcpy_simd is the fastest memcpy on almost all cores, replace
the generic memcpy with it.  If SVE is available, a SVE memcpy will be
used by default (including for Neoverse N2).
2022-10-26 14:16:50 +01:00
Wilco Dijkstra
a8e72913fe aarch64: Cleanup memset ifunc
Cleanup memset ifunc selectors. The A64FX memset relies on a ZVA size of
256, so add an explicit check.
2022-10-26 14:12:55 +01:00
Adhemerval Zanella
891a7958a2 elf: Reinstate on DL_DEBUG_BINDINGS _dl_lookup_symbol_x
The prelink removal done by 6628c742b2 wrongly removed the debug
support.

Checked on x86_64-linux-gnu.
2022-10-26 09:47:10 -03:00
Sunil K Pandey
59e501f204 x86_64: Implement evex512 version of strchrnul, strchr and wcschr
This patch implements following evex512 version of string functions.
evex512 version takes up to 30% less cycle as compared to evex,
depending on length and alignment.

- strchrnul function using 512 bit vectors.
- strchr function using 512 bit vectors.
- wcschr function using 512 bit vectors.

Code size data:

strchrnul-evex.o	599 byte
strchrnul-evex512.o	569 byte (-5%)

strchr-evex.o		639 byte
strchr-evex512.o	595 byte (-7%)

wcschr-evex.o		644 byte
wcschr-evex512.o	607 byte (-6%)

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

Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2022-10-25 22:39:35 -07:00
Adhemerval Zanella
7a6ca82f80 linux: Fix generic struct_stat for 64 bit time (BZ# 29657)
The generic Linux struct_stat misses the conditionals to use
bits/struct_stat_time64_helper.h in the __USE_TIME_BITS64 for
architecture that uses __TIMESIZE == 32 (currently csky and nios2).

Since newer ports should not support 32 bit time_t, the generic
implementation should be used as default.

For arm, hppa, and sh a copy of default struct_stat is added,
while for csky and nios a new one based on generic is used, along
with conditionals to use bits/struct_stat_time64_helper.h.

The default struct_stat is also replaced with the generic one.

Checked on aarch64-linux-gnu and arm-linux-gnueabihf.
2022-10-25 15:53:19 -03:00
Jakub Wilk
a35c960dbb manual: Add missing % in int conversion list
Signed-off-by: Jakub Wilk <jwilk@jwilk.net>
2022-10-25 09:12:30 +02:00
Aurelien Jarno
2b5478569e Avoid undefined behaviour in ibm128 implementation of llroundl (BZ #29488)
Detecting an overflow edge case depended on signed overflow of a long
long. Replace the additions and the overflow checks by
__builtin_add_overflow().

Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
2022-10-24 20:48:02 +02:00
Adhemerval Zanella
be930668ec Remove all assembly optimizations for htonl and htons
The builtin bswap is already used if optimziation is enabled for
GCC 4.8+, so glibc symbols will be used in a very limited scenarios.

Also, gcc generated code is quite similar to all but ia64 and i386
htons.

Checked on alpha, i686, and ia64.
2022-10-24 11:40:08 -03:00
Cristian Rodríguez
29ff5b5b72 Remove htonl.S for i386/x86_64
Generic implementation on top of __bswap_32 always expands
inline to either bswap or movbe depending on -march=*.

Signed-off-by: Cristian Rodríguez <crrodriguez@opensuse.org>
2022-10-24 11:17:22 -03:00
Michael Hudson-Doyle
b6e37b7805 Fix BZ #29463 in the ibm128 implementation of y1l too
Avoid moving code across SET_RESTORE_ROUNDL in order to fix
[BZ #29463].

Tested-by: Aurelien Jarno <aurelien@aurel32.net>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
2022-10-24 10:59:20 -03:00
Joseph Myers
b87a70e5e2 Add ADDRB from Linux 6.0 to bits/termios-c_cflag.h
Linux 6.0 adds a constant ADDRB, a termios c_cflag bit, to its
include/uapi/asm-generic/termbits-common.h.

Add it accordingly to glibc's bits/termios-c_cflag.h headers.  As
other constants in these headers are generally in octal, I converted
the value to octal to match.  As ADDRB isn't in a POSIX-reserved
namespace, I made it conditional on __USE_MISC.

Tested for x86_64.
2022-10-24 13:43:19 +00:00
Noah Goldstein
8775479804 x86: Use testb for FSRM check in memmove-vec-unaligned-erms
`testb` saves a bit of code size is the imm-operand can be encoded
1-bytes.

Tested on x86-64.
2022-10-20 11:29:05 -07:00
Noah Goldstein
f04f8373dd x86: Use testb for case-locale check in str{n}casecmp-sse42
`testb` saves a bit of code size is the imm-operand can be encoded
1-bytes.

Tested on x86-64.
2022-10-20 11:29:05 -07:00
Noah Goldstein
7775574ce0 x86: Use testb for case-locale check in str{n}casecmp-sse2
`testb` saves a bit of code size is the imm-operand can be encoded
1-bytes.

Tested on x86-64.
2022-10-20 11:29:05 -07:00
Noah Goldstein
b6d02d6457 x86: Use testb for case-locale check in str{n}casecmp-avx2
`testb` saves a bit of code size is the imm-operand can be encoded
1-bytes.

Tested on x86-64.
2022-10-20 11:29:05 -07:00
Noah Goldstein
5ce9766417 x86: Add support for VEC_SIZE == 64 in strcmp-evex.S impl
Unused at the moment, but evex512 strcmp, strncmp, strcasecmp{l}, and
strncasecmp{l} functions can be added by including strcmp-evex.S with
"x86-evex512-vecs.h" defined.

In addition save code size a bit in a few places.

1. tzcnt ...         -> bsf ...
2. vpcmp{b|d} $0 ... -> vpcmpeq{b|d}

This saves a touch of code size but has minimal net affect.

Full check passes on x86-64.
2022-10-20 11:29:05 -07:00
Noah Goldstein
c25eb94aed x86: Remove AVX512-BVMI2 instruction from strrchr-evex.S
commit b412213eee
    Author: Noah Goldstein <goldstein.w.n@gmail.com>
    Date:   Tue Oct 18 17:44:07 2022 -0700

        x86: Optimize strrchr-evex.S and implement with VMM headers

Added `vpcompress{b|d}` to the page-cross logic with is an
AVX512-VBMI2 instruction. This is not supported on SKX. Since the
page-cross logic is relatively cold and the benefit is minimal
revert the page-cross case back to the old logic which is supported
on SKX.

Tested on x86-64.
2022-10-20 11:29:05 -07:00
Felix Riemann
a885fc2d68 sysdeps: arm: Fix preconfigure script for ARMv8/v9 targets [BZ #29698]
The ARM preconfigure script tries to detect the capabilities of the
target platform by checking the compiler's predefined architecture
macros. However, if the compiler is tuning for AArch32 on ARMv8/v9 this
step fails:

checking for sysdeps preconfigure fragments... aarch64 alpha arc arm
WARNING: arm/preconfigure: Did not find ARM architecture type; using default

This is because preconfigure.ac doesn't escape the square brackets in
the glob for matching compilers targeting ARMv8. Adding another pair of
brackets to escape the first pair fixes this:

checking for sysdeps preconfigure fragments... aarch64 alpha arc arm
 Found compiler is configured for something newer than v7 - using v7

Signed-off-by: Felix Riemann <felix.riemann@sma.de>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2022-10-20 11:23:05 -03:00
Adhemerval Zanella Netto
0ff92021c0 nis: Fix nis_print_directory
Remove implicit conversion from enumeration type 'zotypes' to different
type 'nstype'.

Checked on x86_64-linux-gnu.
Reviewed-by: Arjun Shankar <arjun@redhat.com>
2022-10-20 10:54:27 -03:00
Adhemerval Zanella
9b5e138f2b linux: Avoid shifting a negative signed on POSIX timer interface
The current macros uses pid as signed value, which triggers a compiler
warning for process and thread timers.  Replace MAKE_PROCESS_CPUCLOCK
with static inline function that expects the pid as unsigned.  These
are similar to what Linux does internally.

Checked on x86_64-linux-gnu.
Reviewed-by: Arjun Shankar <arjun@redhat.com>
2022-10-20 10:19:08 -03:00
Noah Goldstein
643a2d0139 Bench: Improve benchtests for memchr, strchr, strnlen, strrchr
1. Add more complete coverage in the medium size range.
2. In strnlen remove the `1 << i` which was UB (`i` could go beyond
   32/64)
2022-10-19 17:31:03 -07:00
Noah Goldstein
b412213eee x86: Optimize strrchr-evex.S and implement with VMM headers
Optimization is:
1. Cache latest result in "fast path" loop with `vmovdqu` instead of
  `kunpckdq`.  This helps if there are more than one matches.

Code Size Changes:
strrchr-evex.S       :  +30 bytes (Same number of cache lines)

Net perf changes:

Reported as geometric mean of all improvements / regressions from N=10
runs of the benchtests. Value as New Time / Old Time so < 1.0 is
improvement and 1.0 is regression.

strrchr-evex.S       : 0.932 (From cases with higher match frequency)

Full results attached in email.

Full check passes on x86-64.
2022-10-19 17:31:03 -07:00
Noah Goldstein
4af6844aa5 x86: Optimize memrchr-evex.S
Optimizations are:
1. Use the fact that lzcnt(0) -> VEC_SIZE for memchr to save a branch
   in short string case.
2. Save several instructions in len = [VEC_SIZE, 4 * VEC_SIZE] case.
3. Use more code-size efficient instructions.
	- tzcnt ...     -> bsf ...
	- vpcmpb $0 ... -> vpcmpeq ...

Code Size Changes:
memrchr-evex.S      :  -29 bytes

Net perf changes:

Reported as geometric mean of all improvements / regressions from N=10
runs of the benchtests. Value as New Time / Old Time so < 1.0 is
improvement and 1.0 is regression.

memrchr-evex.S      : 0.949 (Mostly from improvements in small strings)

Full results attached in email.

Full check passes on x86-64.
2022-10-19 17:31:03 -07:00
Noah Goldstein
b79f8ff26a x86: Optimize strnlen-evex.S and implement with VMM headers
Optimizations are:
1. Use the fact that bsf(0) leaves the destination unchanged to save a
   branch in short string case.
2. Restructure code so that small strings are given the hot path.
        - This is a net-zero on the benchmark suite but in general makes
      sense as smaller sizes are far more common.
3. Use more code-size efficient instructions.
	- tzcnt ...     -> bsf ...
	- vpcmpb $0 ... -> vpcmpeq ...
4. Align labels less aggressively, especially if it doesn't save fetch
   blocks / causes the basic-block to span extra cache-lines.

The optimizations (especially for point 2) make the strnlen and
strlen code essentially incompatible so split strnlen-evex
to a new file.

Code Size Changes:
strlen-evex.S       :  -23 bytes
strnlen-evex.S      : -167 bytes

Net perf changes:

Reported as geometric mean of all improvements / regressions from N=10
runs of the benchtests. Value as New Time / Old Time so < 1.0 is
improvement and 1.0 is regression.

strlen-evex.S       : 0.992 (No real change)
strnlen-evex.S      : 0.947

Full results attached in email.

Full check passes on x86-64.
2022-10-19 17:31:03 -07:00
Noah Goldstein
69717709ec x86: Shrink / minorly optimize strchr-evex and implement with VMM headers
Size Optimizations:
1. Condence hot path for better cache-locality.
    - This is most impact for strchrnul where the logic strings with
      len <= VEC_SIZE or with a match in the first VEC no fits entirely
      in the first cache line.
2. Reuse common targets in first 4x VEC and after the loop.
3. Don't align targets so aggressively if it doesn't change the number
   of fetch blocks it will require and put more care in avoiding the
   case where targets unnecessarily split cache lines.
4. Align the loop better for DSB/LSD
5. Use more code-size efficient instructions.
	- tzcnt ...     -> bsf ...
	- vpcmpb $0 ... -> vpcmpeq ...
6. Align labels less aggressively, especially if it doesn't save fetch
   blocks / causes the basic-block to span extra cache-lines.

Code Size Changes:
strchr-evex.S	: -63 bytes
strchrnul-evex.S: -48 bytes

Net perf changes:
Reported as geometric mean of all improvements / regressions from N=10
runs of the benchtests. Value as New Time / Old Time so < 1.0 is
improvement and 1.0 is regression.

strchr-evex.S (Fixed)   : 0.971
strchr-evex.S (Rand)    : 0.932
strchrnul-evex.S        : 0.965

Full results attached in email.

Full check passes on x86-64.
2022-10-19 17:31:03 -07:00
Noah Goldstein
330881763e x86: Optimize memchr-evex.S and implement with VMM headers
Optimizations are:

1. Use the fact that tzcnt(0) -> VEC_SIZE for memchr to save a branch
   in short string case.
2. Restructure code so that small strings are given the hot path.
	- This is a net-zero on the benchmark suite but in general makes
      sense as smaller sizes are far more common.
3. Use more code-size efficient instructions.
	- tzcnt ...     -> bsf ...
	- vpcmpb $0 ... -> vpcmpeq ...
4. Align labels less aggressively, especially if it doesn't save fetch
   blocks / causes the basic-block to span extra cache-lines.

The optimizations (especially for point 2) make the memchr and
rawmemchr code essentially incompatible so split rawmemchr-evex
to a new file.

Code Size Changes:
memchr-evex.S       : -107 bytes
rawmemchr-evex.S    :  -53 bytes

Net perf changes:

Reported as geometric mean of all improvements / regressions from N=10
runs of the benchtests. Value as New Time / Old Time so < 1.0 is
improvement and 1.0 is regression.

memchr-evex.S       : 0.928
rawmemchr-evex.S    : 0.986 (Less targets cross cache lines)

Full results attached in email.

Full check passes on x86-64.
2022-10-19 17:31:03 -07:00
Sunil K Pandey
451c6e5854 x86_64: Implement evex512 version of memchr, rawmemchr and wmemchr
This patch implements following evex512 version of string functions.
evex512 version takes up to 30% less cycle as compared to evex,
depending on length and alignment.

- memchr function using 512 bit vectors.
- rawmemchr function using 512 bit vectors.
- wmemchr function using 512 bit vectors.

Code size data:

memchr-evex.o		762 byte
memchr-evex512.o	576 byte (-24%)

rawmemchr-evex.o	461 byte
rawmemchr-evex512.o	412 byte (-11%)

wmemchr-evex.o		794 byte
wmemchr-evex512.o	552 byte (-30%)

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

Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2022-10-18 13:26:33 -07:00
Sunil K Pandey
932dd83efd String: Improve test coverage for memchr
This test improves memchr coverage near page boundary.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2022-10-18 09:10:33 -07:00