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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.
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H.J. Lu
H.J. Lu committed Apr 1, 2016
1 parent 2e51bc3 commit 27d3ce1467990f89126e228559dec8f84b96c60e
Showing with 6 additions and 5 deletions.
  1. +5 −0 ChangeLog
  2. +1 −5 sysdeps/x86/cpu-features.c
@@ -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.
@@ -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);

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