1 /* Multiple versions of strncmp.
2 All versions must be listed in ifunc-impl-list.c.
3 Copyright (C) 2017-2022 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20 /* Define multiple versions only for the definition in libc. */
21 #if IS_IN (libc)
22 # define strncmp __redirect_strncmp
23 # include <string.h>
24 # undef strncmp
25
26 # define SYMBOL_NAME strncmp
27 # include <init-arch.h>
28
29 extern __typeof (REDIRECT_NAME) OPTIMIZE (evex) attribute_hidden;
30
31 extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2) attribute_hidden;
32 extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_rtm) attribute_hidden;
33
34 extern __typeof (REDIRECT_NAME) OPTIMIZE (sse42) attribute_hidden;
35
36 extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;
37
38 static inline void *
IFUNC_SELECTOR(void)39 IFUNC_SELECTOR (void)
40 {
41 const struct cpu_features *cpu_features = __get_cpu_features ();
42
43 if (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX2)
44 && X86_ISA_CPU_FEATURES_ARCH_P (cpu_features,
45 AVX_Fast_Unaligned_Load, ))
46 {
47 if (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX512VL)
48 && X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX512BW)
49 && X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, BMI2))
50 return OPTIMIZE (evex);
51
52 if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
53 return OPTIMIZE (avx2_rtm);
54
55 if (X86_ISA_CPU_FEATURES_ARCH_P (cpu_features,
56 Prefer_No_VZEROUPPER, !))
57 return OPTIMIZE (avx2);
58 }
59
60 if (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, SSE4_2)
61 && !CPU_FEATURES_ARCH_P (cpu_features, Slow_SSE4_2))
62 return OPTIMIZE (sse42);
63
64 return OPTIMIZE (sse2);
65 }
66
67 libc_ifunc_redirected (__redirect_strncmp, strncmp, IFUNC_SELECTOR ());
68
69 # ifdef SHARED
70 __hidden_ver1 (strncmp, __GI_strncmp, __redirect_strncmp)
71 __attribute__ ((visibility ("hidden"))) __attribute_copy__ (strncmp);
72 # endif
73 #endif
74