glibc/sysdeps/x86_64/multiarch/wcsnlen-evex.S

#ifndef WCSNLEN
# define WCSNLEN	__wcsnlen_evex
#endif

#define STRNLEN	WCSNLEN
#define USE_AS_WCSLEN 1

#include "strnlen-evex.S"
x86: Add support to build strcmp/strlen/strchr with explicit ISA level 1. Add default ISA level selection in non-multiarch/rtld implementations. 2. Add ISA level build guards to different implementations. - I.e strcmp-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 (strcmp-evex.S). 3. 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. 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. 2022-07-13 23:32:59 +00:00			`#ifndef WCSNLEN`
			`# define WCSNLEN __wcsnlen_evex`
			`#endif`

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 00:44:05 +00:00			`#define STRNLEN WCSNLEN`
x86-64: Add ifunc-avx2.h functions with 256-bit EVEX Update ifunc-avx2.h, strchr.c, strcmp.c, strncmp.c and wcsnlen.c to select the function optimized with 256-bit EVEX instructions using YMM16-YMM31 registers to avoid RTM abort with usable AVX512VL, AVX512BW and BMI2 since VZEROUPPER isn't needed at function exit. For strcmp/strncmp, prefer AVX2 strcmp/strncmp if Prefer_AVX2_STRCMP is set. 2021-03-05 14:24:52 +00:00			`#define USE_AS_WCSLEN 1`

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 00:44:05 +00:00			`#include "strnlen-evex.S"`