|
 |
3cd4d4 |
From 27d3ce1467990f89126e228559dec8f84b96c60e Mon Sep 17 00:00:00 2001
|
|
|
3cd4d4 |
From: "H.J. Lu" <hjl.tools@gmail.com>
|
|
|
3cd4d4 |
Date: Fri, 1 Apr 2016 15:08:48 -0700
|
|
|
3cd4d4 |
Subject: [PATCH] Remove Fast_Copy_Backward from Intel Core processors
|
|
|
3cd4d4 |
|
|
|
3cd4d4 |
Intel Core i3, i5 and i7 processors have fast unaligned copy and
|
|
|
3cd4d4 |
copy backward is ignored. Remove Fast_Copy_Backward from Intel Core
|
|
|
3cd4d4 |
processors to avoid confusion.
|
|
|
3cd4d4 |
|
|
|
3cd4d4 |
* sysdeps/x86/cpu-features.c (init_cpu_features): Don't set
|
|
|
3cd4d4 |
bit_arch_Fast_Copy_Backward for Intel Core proessors.
|
|
|
3cd4d4 |
---
|
|
|
3cd4d4 |
ChangeLog | 5 +++++
|
|
|
3cd4d4 |
sysdeps/x86/cpu-features.c | 6 +-----
|
|
|
3cd4d4 |
2 files changed, 6 insertions(+), 5 deletions(-)
|
|
|
3cd4d4 |
|
|
|
3cd4d4 |
diff -rup a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
|
|
|
3cd4d4 |
--- a/sysdeps/x86/cpu-features.c 2020-01-21 16:44:28.637555853 -0500
|
|
|
3cd4d4 |
+++ b/sysdeps/x86/cpu-features.c 2020-01-21 16:46:51.208756416 -0500
|
|
|
3cd4d4 |
@@ -116,11 +116,8 @@ init_cpu_features (struct cpu_features *
|
|
|
3cd4d4 |
case 0x2c:
|
|
|
3cd4d4 |
case 0x2e:
|
|
|
3cd4d4 |
case 0x2f:
|
|
|
3cd4d4 |
- /* Rep string instructions, copy backward, unaligned loads
|
|
|
3cd4d4 |
+ /* Rep string instructions, unaligned load, unaligned copy,
|
|
|
3cd4d4 |
and pminub are fast on Intel Core i3, i5 and i7. */
|
|
|
3cd4d4 |
-#if index_Fast_Rep_String != index_Fast_Copy_Backward
|
|
|
3cd4d4 |
-# error index_Fast_Rep_String != index_Fast_Copy_Backward
|
|
|
3cd4d4 |
-#endif
|
|
|
3cd4d4 |
#if index_Fast_Rep_String != index_Fast_Unaligned_Load
|
|
|
3cd4d4 |
# error index_Fast_Rep_String != index_Fast_Unaligned_Load
|
|
|
3cd4d4 |
#endif
|
|
|
3cd4d4 |
@@ -129,7 +126,6 @@ init_cpu_features (struct cpu_features *
|
|
|
3cd4d4 |
#endif
|
|
|
3cd4d4 |
cpu_features->feature[index_Fast_Rep_String]
|
|
|
3cd4d4 |
|= (bit_Fast_Rep_String
|
|
|
3cd4d4 |
- | bit_Fast_Copy_Backward
|
|
|
3cd4d4 |
| bit_Fast_Unaligned_Load
|
|
|
3cd4d4 |
| bit_Prefer_PMINUB_for_stringop);
|
|
|
3cd4d4 |
break;
|
|
|
3cd4d4 |
|