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Use AVX_Fast_Unaligned_Load from Zen onwards.

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From Zen onwards this will be enabled. It was disabled for the
Excavator case and will remain disabled.

Reviewd-by: Carlos O'Donell <carlos@redhat.com>
This commit is contained in:
Amit Pawar
2018-07-06 09:55:36 -04:00
committed by Carlos O'Donell
parent 3a885c1f51
commit bce5911b67
2 changed files with 20 additions and 5 deletions
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18
sysdeps/x86/cpu-features.c
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@@ -78,8 +78,15 @@ get_common_indeces (struct cpu_features *cpu_features,
/* The following features depend on AVX being usable. */
/* Determine if AVX2 is usable. */
if (CPU_FEATURES_CPU_P (cpu_features, AVX2))
{
cpu_features->feature[index_arch_AVX2_Usable]
|= bit_arch_AVX2_Usable;
/* Unaligned load with 256-bit AVX registers are faster on
Intel/AMD processors with AVX2. */
cpu_features->feature[index_arch_AVX_Fast_Unaligned_Load]
|= bit_arch_AVX_Fast_Unaligned_Load;
}
/* Determine if FMA is usable. */
if (CPU_FEATURES_CPU_P (cpu_features, FMA))
cpu_features->feature[index_arch_FMA_Usable]
@@ -298,11 +305,6 @@ init_cpu_features (struct cpu_features *cpu_features)
}
}
/* Unaligned load with 256-bit AVX registers are faster on
Intel processors with AVX2. */
if (CPU_FEATURES_ARCH_P (cpu_features, AVX2_Usable))
cpu_features->feature[index_arch_AVX_Fast_Unaligned_Load]
|= bit_arch_AVX_Fast_Unaligned_Load;
/* Since AVX512ER is unique to Xeon Phi, set Prefer_No_VZEROUPPER
if AVX512ER is available. Don't use AVX512 to avoid lower CPU
@@ -351,9 +353,15 @@ init_cpu_features (struct cpu_features *cpu_features)
#endif
/* "Excavator" */
if (model >= 0x60 && model <= 0x7f)
{
cpu_features->feature[index_arch_Fast_Unaligned_Load]
|= (bit_arch_Fast_Unaligned_Load
| bit_arch_Fast_Copy_Backward);
/* Unaligned AVX loads are slower.*/
cpu_features->feature[index_arch_AVX_Fast_Unaligned_Load]
&= ~bit_arch_AVX_Fast_Unaligned_Load;
}
}
}
else