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f46ef33ad1
Optimize strlen using a mix of scalar and SIMD code. On modern micro architectures large strings are 2.6 times faster than existing strlen_asimd and 35% faster than the new MTE version of strlen. On a random strlen benchmark using small sizes the speedup is 7% vs strlen_asimd and 40% vs the MTE strlen. This fixes the main strlen regressions on Cortex-A53 and other cores with a simple Neon unit. Rename __strlen_generic to __strlen_mte, and select strlen_asimd when MTE is not enabled (this is waiting on support for a HWCAP_MTE bit). This fixes big-endian bug 25824. Passes GLIBC regression tests. Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
42 lines
1.5 KiB
C
42 lines
1.5 KiB
C
/* Multiple versions of strlen. AARCH64 version.
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Copyright (C) 2018-2020 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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/* Define multiple versions only for the definition in libc. */
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#if IS_IN (libc)
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/* Redefine strlen so that the compiler won't complain about the type
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mismatch with the IFUNC selector in strong_alias, below. */
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# undef strlen
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# define strlen __redirect_strlen
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# include <string.h>
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# include <init-arch.h>
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/* This should check HWCAP_MTE when it is available. */
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#define MTE_ENABLED() (false)
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extern __typeof (__redirect_strlen) __strlen;
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extern __typeof (__redirect_strlen) __strlen_mte attribute_hidden;
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extern __typeof (__redirect_strlen) __strlen_asimd attribute_hidden;
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libc_ifunc (__strlen, (MTE_ENABLED () ? __strlen_mte : __strlen_asimd));
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# undef strlen
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strong_alias (__strlen, strlen);
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#endif
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