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c69f960b01
The changes for these functions are different than the others because
the best implementation (sse4_2) requires the generic
implementation as a fallback to be built as well.
Changes are:
1. Add non-multiarch functions for str{c|p}{brk|spn}.c to statically
select the best implementation based on the configured ISA build
level.
2. Add stubs for str{c|p}{brk|spn}-generic and varshift.c to in the
sysdeps/x86_64 directory so that the the sse4 implementation will
have all of its dependencies for the non-multiarch / rtld build
when ISA level >= 2.
3. Add new multiarch/rtld-strcspn.c that just include the
non-multiarch strcspn.c 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.
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.
41 lines
1.6 KiB
C
41 lines
1.6 KiB
C
/* Common definition for ifunc selections optimized with SSE2 and SSE4.2.
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All versions must be listed in ifunc-impl-list.c.
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Copyright (C) 2017-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <init-arch.h>
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extern __typeof (REDIRECT_NAME) OPTIMIZE (generic) attribute_hidden;
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extern __typeof (REDIRECT_NAME) OPTIMIZE (sse42) attribute_hidden;
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static inline void *
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IFUNC_SELECTOR (void)
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{
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const struct cpu_features* cpu_features = __get_cpu_features ();
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/* This function uses the `pcmpstri` sse4.2 instruction which can be
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slow on some CPUs. This normally would be guarded by a
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Slow_SSE4_2 check, but since there is no other optimized
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implementation its best to keep it regardless. If an optimized
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fallback is added add a X86_ISA_CPU_FEATURE_ARCH_P (cpu_features,
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Slow_SSE4_2) check. */
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if (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, SSE4_2))
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return OPTIMIZE (sse42);
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return OPTIMIZE (generic);
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}
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