Detect i586 and i686 features at run-time

We detect i586 and i686 features at run-time by checking CX8 and CMOV
CPUID features bits.  We can use these information to select the best
implementation in ix86 multiarch.  HAS_I586 and HAS_I686 are changed
run-time check.  SUPPORT_I586 and SUPPORT_I686 are added for
compile-time check.

	* sysdeps/x86/cpu-features.c (init_cpu_features): Set bit_I586
	bit if CX8 is available.  Set bit_I686 bit if CMOV is available.
	* sysdeps/x86/cpu-features.h (bit_I586): New.
	(bit_I686): Likewise.
	(bit_CX8): Likewise.
	(bit_CMOV): Likewise.
	(index_CX8): Likewise.
	(index_CMOV): Likewise.
	(index_I586): Likewise.
	(index_I686): Likewise.
	(reg_CX8): Likewise.
	(reg_CMOV): Likewise.
	(HAS_I586): Renamed to ...
	(SUPPORT_I586): This.
	(HAS_I686): Renamed to ...
	(SUPPORT_I686): This.
	(HAS_I586): Defined as HAS_ARCH_FEATURE (I586) if i586 isn't
	available at compile-time.
	(HAS_I686): Defined as HAS_ARCH_FEATURE (I686) if i686 isn't
	available at compile-time.

2 files changed, 31 insertions, 3 deletions

diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
index 40575de611..b03451dde1 100644
--- a/sysdeps/x86/cpu-features.c
+++ b/sysdeps/x86/cpu-features.c
@@ -150,6 +150,14 @@ init_cpu_features (struct cpu_features *cpu_features)
   else
     kind = arch_kind_other;
 
+  /* Support i586 if CX8 is available.  */
+  if (HAS_CPU_FEATURE (CX8))
+    cpu_features->feature[index_I586] |= bit_I586;
+
+  /* Support i686 if CMOV is available.  */
+  if (HAS_CPU_FEATURE (CMOV))
+    cpu_features->feature[index_I686] |= bit_I686;
+
   if (cpu_features->max_cpuid >= 7)
     __cpuid_count (7, 0,
 		   cpu_features->cpuid[COMMON_CPUID_INDEX_7].eax,
diff --git a/sysdeps/x86/cpu-features.h b/sysdeps/x86/cpu-features.h
index 6e706241ad..2c0a3fd685 100644
--- a/sysdeps/x86/cpu-features.h
+++ b/sysdeps/x86/cpu-features.h
@@ -31,10 +31,14 @@
 #define bit_AVX_Fast_Unaligned_Load	(1 << 11)
 #define bit_AVX512F_Usable		(1 << 12)
 #define bit_AVX512DQ_Usable		(1 << 13)
+#define bit_I586			(1 << 14)
+#define bit_I686			(1 << 15)
 
 /* CPUID Feature flags.  */
 
 /* COMMON_CPUID_INDEX_1.  */
+#define bit_CX8		(1 << 8)
+#define bit_CMOV	(1 << 15)
 #define bit_SSE2	(1 << 26)
 #define bit_SSSE3	(1 << 9)
 #define bit_SSE4_1	(1 << 19)
@@ -69,6 +73,8 @@
 # include <ifunc-defines.h>
 # include <rtld-global-offsets.h>
 
+# define index_CX8	COMMON_CPUID_INDEX_1*CPUID_SIZE+CPUID_EDX_OFFSET
+# define index_CMOV	COMMON_CPUID_INDEX_1*CPUID_SIZE+CPUID_EDX_OFFSET
 # define index_SSE2	COMMON_CPUID_INDEX_1*CPUID_SIZE+CPUID_EDX_OFFSET
 # define index_SSSE3	COMMON_CPUID_INDEX_1*CPUID_SIZE+CPUID_ECX_OFFSET
 # define index_SSE4_1	COMMON_CPUID_INDEX_1*CPUID_SIZE+CPUID_ECX_OFFSET
@@ -89,6 +95,8 @@
 # define index_AVX_Fast_Unaligned_Load	FEATURE_INDEX_1*FEATURE_SIZE
 # define index_AVX512F_Usable		FEATURE_INDEX_1*FEATURE_SIZE
 # define index_AVX512DQ_Usable		FEATURE_INDEX_1*FEATURE_SIZE
+# define index_I586			FEATURE_INDEX_1*FEATURE_SIZE
+# define index_I686			FEATURE_INDEX_1*FEATURE_SIZE
 
 # if defined (_LIBC) && !IS_IN (nonlib)
 #  ifdef __x86_64__
@@ -193,6 +201,8 @@ extern const struct cpu_features *__get_cpu_features (void)
 # define HAS_ARCH_FEATURE(name) \
   ((__get_cpu_features ()->feature[index_##name] & (bit_##name)) != 0)
 
+# define index_CX8		COMMON_CPUID_INDEX_1
+# define index_CMOV		COMMON_CPUID_INDEX_1
 # define index_SSE2		COMMON_CPUID_INDEX_1
 # define index_SSSE3		COMMON_CPUID_INDEX_1
 # define index_SSE4_1		COMMON_CPUID_INDEX_1
@@ -207,6 +217,8 @@ extern const struct cpu_features *__get_cpu_features (void)
 # define index_POPCOUNT		COMMON_CPUID_INDEX_1
 # define index_OSXSAVE		COMMON_CPUID_INDEX_1
 
+# define reg_CX8		edx
+# define reg_CMOV		edx
 # define reg_SSE2		edx
 # define reg_SSSE3		ecx
 # define reg_SSE4_1		ecx
@@ -234,6 +246,8 @@ extern const struct cpu_features *__get_cpu_features (void)
 # define index_AVX_Fast_Unaligned_Load	FEATURE_INDEX_1
 # define index_AVX512F_Usable		FEATURE_INDEX_1
 # define index_AVX512DQ_Usable		FEATURE_INDEX_1
+# define index_I586			FEATURE_INDEX_1
+# define index_I686			FEATURE_INDEX_1
 
 #endif	/* !__ASSEMBLER__ */
 
@@ -242,7 +256,9 @@ extern const struct cpu_features *__get_cpu_features (void)
 #elif defined __i586__ || defined __pentium__
 # define HAS_CPUID 1
 # define HAS_I586 1
-# define HAS_I686 0
+# define HAS_I686 HAS_ARCH_FEATURE (I686)
+# define SUPPORT_I586 1
+# define SUPPORT_I686 0
 #elif (defined __i686__ || defined __pentiumpro__		\
        || defined __pentium4__ || defined __nocona__		\
        || defined __atom__ || defined __core2__			\
@@ -259,10 +275,14 @@ extern const struct cpu_features *__get_cpu_features (void)
 # define HAS_CPUID 1
 # define HAS_I586 1
 # define HAS_I686 1
+# define SUPPORT_I586 1
+# define SUPPORT_I686 1
 #else
 # define HAS_CPUID 0
-# define HAS_I586 0
-# define HAS_I686 0
+# define HAS_I586 HAS_ARCH_FEATURE (I586)
+# define HAS_I686 HAS_ARCH_FEATURE (I686)
+# define SUPPORT_I586 0
+# define SUPPORT_I686 0
 #endif
 
 #endif  /* cpu_features_h */