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56 lines
2.4 KiB
56 lines
2.4 KiB
commit 36d6b9be3d7008a78e1f6e2e2db1947b76b206d8 |
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Author: Aurelien Jarno <aurelien@aurel32.net> |
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Date: Mon Oct 3 23:16:46 2022 +0200 |
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x86-64: Require BMI2 and LZCNT for AVX2 memrchr implementation |
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The AVX2 memrchr implementation uses the 'shlxl' instruction, which |
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belongs to the BMI2 CPU feature and uses the 'lzcnt' instruction, which |
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belongs to the LZCNT CPU feature. |
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Fixes: af5306a735eb ("x86: Optimize memrchr-avx2.S") |
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Partially resolves: BZ #29611 |
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Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com> |
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(cherry picked from commit 3c0c78afabfed4b6fc161c159e628fbf14ff370b) |
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diff --git a/sysdeps/x86_64/multiarch/ifunc-avx2.h b/sysdeps/x86_64/multiarch/ifunc-avx2.h |
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index 6de72f72724b81ba..52bd00ea5cab6b22 100644 |
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--- a/sysdeps/x86_64/multiarch/ifunc-avx2.h |
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+++ b/sysdeps/x86_64/multiarch/ifunc-avx2.h |
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@@ -31,6 +31,7 @@ IFUNC_SELECTOR (void) |
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if (CPU_FEATURE_USABLE_P (cpu_features, AVX2) |
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&& CPU_FEATURE_USABLE_P (cpu_features, BMI2) |
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+ && CPU_FEATURE_USABLE_P (cpu_features, LZCNT) |
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&& CPU_FEATURES_ARCH_P (cpu_features, AVX_Fast_Unaligned_Load)) |
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{ |
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if (CPU_FEATURE_USABLE_P (cpu_features, AVX512VL) |
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diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c |
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index 81640cf00664e3ed..d1fc1e75d6706413 100644 |
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--- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c |
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+++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c |
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@@ -174,15 +174,21 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array, |
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/* Support sysdeps/x86_64/multiarch/memrchr.c. */ |
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IFUNC_IMPL (i, name, memrchr, |
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IFUNC_IMPL_ADD (array, i, memrchr, |
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- CPU_FEATURE_USABLE (AVX2), |
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+ (CPU_FEATURE_USABLE (AVX2) |
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+ && CPU_FEATURE_USABLE (BMI2) |
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+ && CPU_FEATURE_USABLE (LZCNT)), |
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__memrchr_avx2) |
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IFUNC_IMPL_ADD (array, i, memrchr, |
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(CPU_FEATURE_USABLE (AVX2) |
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+ && CPU_FEATURE_USABLE (BMI2) |
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+ && CPU_FEATURE_USABLE (LZCNT) |
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&& CPU_FEATURE_USABLE (RTM)), |
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__memrchr_avx2_rtm) |
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IFUNC_IMPL_ADD (array, i, memrchr, |
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(CPU_FEATURE_USABLE (AVX512VL) |
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- && CPU_FEATURE_USABLE (AVX512BW)), |
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+ && CPU_FEATURE_USABLE (AVX512BW) |
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+ && CPU_FEATURE_USABLE (BMI2) |
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+ && CPU_FEATURE_USABLE (LZCNT)), |
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__memrchr_evex) |
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IFUNC_IMPL_ADD (array, i, memrchr, 1, __memrchr_sse2))
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