diff --git a/sysdeps/i386/i486/init-arch.h b/sysdeps/i386/i486/init-arch.h
new file mode 100644
index 0000000..0c74ddc
--- /dev/null
+++ b/sysdeps/i386/i486/init-arch.h
@@ -0,0 +1,19 @@
+/* Copyright (C) 2015 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#define MINIMUM_ISA 486
+#include <sysdeps/x86/init-arch.h>
diff --git a/sysdeps/i386/i586/init-arch.h b/sysdeps/i386/i586/init-arch.h
new file mode 100644
index 0000000..50c43a2
--- /dev/null
+++ b/sysdeps/i386/i586/init-arch.h
@@ -0,0 +1,19 @@
+/* Copyright (C) 2015 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#define MINIMUM_ISA 586
+#include <sysdeps/x86/init-arch.h>
diff --git a/sysdeps/i386/i686/init-arch.h b/sysdeps/i386/i686/init-arch.h
new file mode 100644
index 0000000..b4a2735
--- /dev/null
+++ b/sysdeps/i386/i686/init-arch.h
@@ -0,0 +1,19 @@
+/* Copyright (C) 2015 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#define MINIMUM_ISA 686
+#include <sysdeps/x86/init-arch.h>
diff --git a/sysdeps/i386/init-arch.h b/sysdeps/i386/init-arch.h
new file mode 100644
index 0000000..9adb451
--- /dev/null
+++ b/sysdeps/i386/init-arch.h
@@ -0,0 +1,19 @@
+/* Copyright (C) 2015 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#define MINIMUM_ISA 386
+#include <sysdeps/x86/init-arch.h>
diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
index 40575de..b03451d 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 6e70624..80edbee 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 +256,7 @@ 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)
 #elif (defined __i686__ || defined __pentiumpro__		\
        || defined __pentium4__ || defined __nocona__		\
        || defined __atom__ || defined __core2__			\
@@ -261,8 +275,8 @@ extern const struct cpu_features *__get_cpu_features (void)
 # define HAS_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)
 #endif
 
 #endif  /* cpu_features_h */
diff --git a/sysdeps/x86/init-arch.h b/sysdeps/x86/init-arch.h
index 2b9988e..5ee0957 100644
--- a/sysdeps/x86/init-arch.h
+++ b/sysdeps/x86/init-arch.h
@@ -20,3 +20,16 @@
 #else
 # include <ldsodefs.h>
 #endif
+
+#ifndef __x86_64__
+/* Due to the reordering and the other nifty extensions in i686, it is
+   not really good to use heavily i586 optimized code on an i686.  It's
+   better to use i486 or i386 code if it isn't an i586.  */
+# if MINIMUM_ISA == 686
+#  define USE_I586 0
+#  define USE_I686 1
+# else
+#  define USE_I586 (HAS_ARCH_FEATURE (I586) && !HAS_ARCH_FEATURE (I686))
+#  define USE_I686 HAS_ARCH_FEATURE (I686)
+# endif
+#endif
