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Remove Fast_Copy_Backward from Intel Core processors

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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.
This commit is contained in:
H.J. Lu 2016-04-01 15:08:48 -07:00
parent 2e51bc3813
commit 27d3ce1467
2 changed files with 6 additions and 5 deletions
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5
ChangeLog
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@ -1,3 +1,8 @@
2016-04-01 H.J. Lu <hongjiu.lu@intel.com>
* sysdeps/x86/cpu-features.c (init_cpu_features): Don't set
bit_arch_Fast_Copy_Backward for Intel Core proessors.
2016-04-01 Adhemerval Zanella <adhemerval.zanella@linaro.org>
* string/strcspn.c (strcspn): Use PTR_ALIGN_DOWN.

6
sysdeps/x86/cpu-features.c
View File

@ -176,11 +176,8 @@ init_cpu_features (struct cpu_features *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_arch_Fast_Rep_String != index_arch_Fast_Copy_Backward
# error index_arch_Fast_Rep_String != index_arch_Fast_Copy_Backward
#endif
#if index_arch_Fast_Rep_String != index_arch_Fast_Unaligned_Load
# error index_arch_Fast_Rep_String != index_arch_Fast_Unaligned_Load
#endif
@ -192,7 +189,6 @@ init_cpu_features (struct cpu_features *cpu_features)
#endif
cpu_features->feature[index_arch_Fast_Rep_String]
|= (bit_arch_Fast_Rep_String
| bit_arch_Fast_Copy_Backward
| bit_arch_Fast_Unaligned_Load
| bit_arch_Fast_Unaligned_Copy
| bit_arch_Prefer_PMINUB_for_stringop);