From 27d3ce1467990f89126e228559dec8f84b96c60e Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Fri, 1 Apr 2016 15:08:48 -0700 Subject: [PATCH] Remove Fast_Copy_Backward from Intel Core processors Intel Core i3, i5 and i7 processors have fast unaligned copy and copy backward is ignored. Remove Fast_Copy_Backward from Intel Core processors to avoid confusion. * sysdeps/x86/cpu-features.c (init_cpu_features): Don't set bit_arch_Fast_Copy_Backward for Intel Core proessors. --- ChangeLog | 5 +++++ sysdeps/x86/cpu-features.c | 6 +----- 2 files changed, 6 insertions(+), 5 deletions(-) diff -rup a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c --- a/sysdeps/x86/cpu-features.c 2020-01-21 16:44:28.637555853 -0500 +++ b/sysdeps/x86/cpu-features.c 2020-01-21 16:46:51.208756416 -0500 @@ -116,11 +116,8 @@ init_cpu_features (struct cpu_features * case 0x2c: case 0x2e: case 0x2f: - /* Rep string instructions, copy backward, unaligned loads + /* Rep string instructions, unaligned load, unaligned copy, and pminub are fast on Intel Core i3, i5 and i7. */ -#if index_Fast_Rep_String != index_Fast_Copy_Backward -# error index_Fast_Rep_String != index_Fast_Copy_Backward -#endif #if index_Fast_Rep_String != index_Fast_Unaligned_Load # error index_Fast_Rep_String != index_Fast_Unaligned_Load #endif @@ -129,7 +126,6 @@ init_cpu_features (struct cpu_features * #endif cpu_features->feature[index_Fast_Rep_String] |= (bit_Fast_Rep_String - | bit_Fast_Copy_Backward | bit_Fast_Unaligned_Load | bit_Prefer_PMINUB_for_stringop); break;