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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>
40 lines
1.4 KiB
ArmAsm
40 lines
1.4 KiB
ArmAsm
/* A Generic Optimized strlen implementation for AARCH64.
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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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/* The actual strlen code is in ../strlen.S. If we are building libc this file
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defines __strlen_mte. Otherwise the include of ../strlen.S will define
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the normal __strlen entry points. */
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#include <sysdep.h>
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#if IS_IN (libc)
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# define STRLEN __strlen_mte
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/* Do not hide the generic version of strlen, we use it internally. */
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# undef libc_hidden_builtin_def
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# define libc_hidden_builtin_def(name)
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# ifdef SHARED
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/* It doesn't make sense to send libc-internal strlen calls through a PLT. */
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.globl __GI_strlen; __GI_strlen = __strlen_mte
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# endif
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#endif
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#include "../strlen.S"
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