GNU C Library master sources branch hjl/pr19583 created. glibc-2.23-121-gdd036a2

[hjl at sourceware dot org]

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        at  dd036a26804d4bb10f3a74d7b916163b77150884 (commit)

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http://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=dd036a26804d4bb10f3a74d7b916163b77150884

commit dd036a26804d4bb10f3a74d7b916163b77150884
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Wed Mar 23 10:33:19 2016 -0700

    [x86] Add a feature bit: Fast_Unaligned_Copy
    
    On AMD processors, memcpy optimized with unaligned SSE load is
    slower than emcpy optimized with aligned SSSE3 while other string
    functions are faster with unaligned SSE load.  A feature bit,
    Fast_Unaligned_Copy, is added to select memcpy optimized with
    unaligned SSE load.
    
    	[BZ #19583]
    	* sysdeps/x86/cpu-features.c (init_cpu_features): Set
    	Fast_Unaligned_Copy with Fast_Unaligned_Load for Intel
    	processors.  Set Fast_Copy_Backward for AMD Excavator
    	processors.
    	* sysdeps/x86/cpu-features.h (bit_arch_Fast_Unaligned_Copy):
    	New.
    	(index_arch_Fast_Unaligned_Copy): Likewise.
    	* sysdeps/x86_64/multiarch/memcpy.S (__new_memcpy): Check
    	Fast_Unaligned_Copy instead of Fast_Unaligned_Load.

diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
index c8f81ef..d10e657 100644
--- a/sysdeps/x86/cpu-features.c
+++ b/sysdeps/x86/cpu-features.c
@@ -153,8 +153,12 @@ init_cpu_features (struct cpu_features *cpu_features)
 #if index_arch_Fast_Unaligned_Load != index_arch_Slow_SSE4_2
 # error index_arch_Fast_Unaligned_Load != index_arch_Slow_SSE4_2
 #endif
+#if index_arch_Fast_Unaligned_Load != index_arch_Fast_Unaligned_Copy
+# error index_arch_Fast_Unaligned_Load != index_arch_Fast_Unaligned_Copy
+#endif
 	      cpu_features->feature[index_arch_Fast_Unaligned_Load]
 		|= (bit_arch_Fast_Unaligned_Load
+		    | bit_arch_Fast_Unaligned_Copy
 		    | bit_arch_Prefer_PMINUB_for_stringop
 		    | bit_arch_Slow_SSE4_2);
 	      break;
@@ -220,10 +224,14 @@ init_cpu_features (struct cpu_features *cpu_features)
 
       if (family == 0x15)
 	{
+#if index_arch_Fast_Unaligned_Load != index_arch_Fast_Copy_Backward
+# error index_arch_Fast_Unaligned_Load != index_arch_Fast_Copy_Backward
+#endif
 	  /* "Excavator"   */
 	  if (model >= 0x60 && model <= 0x7f)
 	    cpu_features->feature[index_arch_Fast_Unaligned_Load]
-	      |= bit_arch_Fast_Unaligned_Load;
+	      |= (bit_arch_Fast_Unaligned_Load
+		  | bit_arch_Fast_Copy_Backward);
 	}
     }
   else
diff --git a/sysdeps/x86/cpu-features.h b/sysdeps/x86/cpu-features.h
index e06eb7e..bfe1f4c 100644
--- a/sysdeps/x86/cpu-features.h
+++ b/sysdeps/x86/cpu-features.h
@@ -35,6 +35,7 @@
 #define bit_arch_I686				(1 << 15)
 #define bit_arch_Prefer_MAP_32BIT_EXEC		(1 << 16)
 #define bit_arch_Prefer_No_VZEROUPPER		(1 << 17)
+#define bit_arch_Fast_Unaligned_Copy		(1 << 18)
 
 /* CPUID Feature flags.  */
 
@@ -101,6 +102,7 @@
 # define index_arch_I686		FEATURE_INDEX_1*FEATURE_SIZE
 # define index_arch_Prefer_MAP_32BIT_EXEC FEATURE_INDEX_1*FEATURE_SIZE
 # define index_arch_Prefer_No_VZEROUPPER FEATURE_INDEX_1*FEATURE_SIZE
+# define index_arch_Fast_Unaligned_Copy	FEATURE_INDEX_1*FEATURE_SIZE
 
 
 # if defined (_LIBC) && !IS_IN (nonlib)
@@ -265,6 +267,7 @@ extern const struct cpu_features *__get_cpu_features (void)
 # define index_arch_I686		FEATURE_INDEX_1
 # define index_arch_Prefer_MAP_32BIT_EXEC FEATURE_INDEX_1
 # define index_arch_Prefer_No_VZEROUPPER FEATURE_INDEX_1
+# define index_arch_Fast_Unaligned_Copy	FEATURE_INDEX_1
 
 #endif	/* !__ASSEMBLER__ */
 
diff --git a/sysdeps/x86_64/multiarch/memcpy.S b/sysdeps/x86_64/multiarch/memcpy.S
index 8882590..5b045d7 100644
--- a/sysdeps/x86_64/multiarch/memcpy.S
+++ b/sysdeps/x86_64/multiarch/memcpy.S
@@ -42,7 +42,7 @@ ENTRY(__new_memcpy)
 	HAS_ARCH_FEATURE (AVX_Fast_Unaligned_Load)
 	jnz	2f
 	lea	__memcpy_sse2_unaligned(%rip), %RAX_LP
-	HAS_ARCH_FEATURE (Fast_Unaligned_Load)
+	HAS_ARCH_FEATURE (Fast_Unaligned_Copy)
 	jnz	2f
 	lea	__memcpy_sse2(%rip), %RAX_LP
 	HAS_CPU_FEATURE (SSSE3)

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