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91cc803d27
commit 3ec5d83d2a
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Sat Jan 25 14:19:40 2020 -0800
x86-64: Avoid rep movsb with short distance [BZ #27130]
introduced some regressions on Intel processors without Fast Short REP
MOV (FSRM). Add Avoid_Short_Distance_REP_MOVSB to avoid rep movsb with
short distance only on Intel processors with FSRM. bench-memmove-large
on Skylake server shows that cycles of __memmove_evex_unaligned_erms
improves for the following data size:
before after Improvement
length=4127, align1=3, align2=0: 479.38 349.25 27%
length=4223, align1=9, align2=5: 405.62 333.25 18%
length=8223, align1=3, align2=0: 786.12 496.38 37%
length=8319, align1=9, align2=5: 727.50 501.38 31%
length=16415, align1=3, align2=0: 1436.88 840.00 41%
length=16511, align1=9, align2=5: 1375.50 836.38 39%
length=32799, align1=3, align2=0: 2890.00 1860.12 36%
length=32895, align1=9, align2=5: 2891.38 1931.88 33%
37 lines
1.3 KiB
Modula-2
37 lines
1.3 KiB
Modula-2
/* Bits in the PREFERRED_FEATURE_INDEX_1 bitfield of <cpu-features.h>.
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Copyright (C) 2020-2021 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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BIT (Fast_Rep_String)
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BIT (Fast_Copy_Backward)
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BIT (Slow_BSF)
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BIT (Fast_Unaligned_Load)
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BIT (Prefer_PMINUB_for_stringop)
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BIT (Fast_Unaligned_Copy)
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BIT (I586)
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BIT (I686)
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BIT (Slow_SSE4_2)
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BIT (AVX_Fast_Unaligned_Load)
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BIT (Prefer_MAP_32BIT_EXEC)
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BIT (Prefer_No_VZEROUPPER)
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BIT (Prefer_ERMS)
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BIT (Prefer_No_AVX512)
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BIT (MathVec_Prefer_No_AVX512)
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BIT (Prefer_FSRM)
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BIT (Prefer_AVX2_STRCMP)
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BIT (Avoid_Short_Distance_REP_MOVSB)
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