diff --git a/sysdeps/x86/dl-diagnostics-cpu.c b/sysdeps/x86/dl-diagnostics-cpu.c
new file mode 100644
index 0000000000..a2d47dd657
--- /dev/null
+++ b/sysdeps/x86/dl-diagnostics-cpu.c
@@ -0,0 +1,152 @@
+/* Print CPU diagnostics data in ld.so.  x86 version.
+   Copyright (C) 2021 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <dl-diagnostics.h>
+#include <ldsodefs.h>
+
+static void
+print_cpu_features_value (const char *label, uint64_t value)
+{
+  _dl_printf ("x86.cpu_features.");
+  _dl_diagnostics_print_labeled_value (label, value);
+}
+
+static void
+print_cpu_feature_internal (unsigned int index, const char *kind,
+                            unsigned int reg, uint32_t value)
+{
+  _dl_printf ("x86.cpu_features.features[0x%x].%s[0x%x]=0x%x\n",
+              index, kind, reg, value);
+}
+
+static void
+print_cpu_feature_preferred (const char *label, unsigned int flag)
+{
+  _dl_printf("x86.cpu_features.preferred.%s=0x%x\n", label, flag);
+}
+
+void
+_dl_diagnostics_cpu (void)
+{
+  const struct cpu_features *cpu_features = __get_cpu_features ();
+
+  print_cpu_features_value ("basic.kind", cpu_features->basic.kind);
+  print_cpu_features_value ("basic.max_cpuid", cpu_features->basic.max_cpuid);
+  print_cpu_features_value ("basic.family", cpu_features->basic.family);
+  print_cpu_features_value ("basic.model", cpu_features->basic.model);
+  print_cpu_features_value ("basic.stepping", cpu_features->basic.stepping);
+
+  for (unsigned int index = 0; index < CPUID_INDEX_MAX; ++index)
+    {
+      /* The index values are part of the ABI via
+         <sys/platform/x86.h>, so translating them to strings is not
+         necessary.  */
+      for (unsigned int reg = 0; reg < 4; ++reg)
+        print_cpu_feature_internal
+          (index, "cpuid", reg,
+           cpu_features->features[index].cpuid_array[reg]);
+      for (unsigned int reg = 0; reg < 4; ++reg)
+        print_cpu_feature_internal
+          (index, "usable", reg,
+           cpu_features->features[index].usable_array[reg]);
+    }
+
+  /* The preferred indicators are not part of the ABI and need to be
+     translated.  */
+  print_cpu_feature_preferred
+    ("i586", CPU_FEATURE_PREFERRED_P (cpu_features, I586));
+  print_cpu_feature_preferred
+    ("i686", CPU_FEATURE_PREFERRED_P (cpu_features, I686));
+  print_cpu_feature_preferred
+    ("fast_rep_string",
+     CPU_FEATURE_PREFERRED_P (cpu_features, Fast_Rep_String));
+  print_cpu_feature_preferred
+    ("fast_copy_backward",
+     CPU_FEATURE_PREFERRED_P (cpu_features, Fast_Copy_Backward));
+  print_cpu_feature_preferred
+    ("fast_unaligned_load",
+     CPU_FEATURE_PREFERRED_P (cpu_features, Fast_Unaligned_Load));
+  print_cpu_feature_preferred
+    ("fast_unaligned_copy",
+     CPU_FEATURE_PREFERRED_P (cpu_features, Fast_Unaligned_Copy));
+  print_cpu_feature_preferred
+    ("slow_bsf", CPU_FEATURE_PREFERRED_P (cpu_features, Slow_BSF));
+  print_cpu_feature_preferred
+    ("slow_sse4_2", CPU_FEATURE_PREFERRED_P (cpu_features, Slow_SSE4_2));
+  print_cpu_feature_preferred
+    ("avx_fast_unaligned_load",
+     CPU_FEATURE_PREFERRED_P (cpu_features, AVX_Fast_Unaligned_Load));
+  print_cpu_feature_preferred
+    ("prefer_map_32bit_exec",
+     CPU_FEATURE_PREFERRED_P (cpu_features, Prefer_MAP_32BIT_EXEC));
+  print_cpu_feature_preferred
+    ("prefer_pminub_for_stringop",
+     CPU_FEATURE_PREFERRED_P (cpu_features, Prefer_PMINUB_for_stringop));
+  print_cpu_feature_preferred
+    ("prefer_no_vzeroupper",
+     CPU_FEATURE_PREFERRED_P (cpu_features, Prefer_No_VZEROUPPER));
+  print_cpu_feature_preferred
+    ("prefer_erms", CPU_FEATURE_PREFERRED_P (cpu_features, Prefer_ERMS));
+  print_cpu_feature_preferred
+    ("prefer_fsrm", CPU_FEATURE_PREFERRED_P (cpu_features, Prefer_FSRM));
+  print_cpu_feature_preferred
+    ("prefer_no_avx512",
+     CPU_FEATURE_PREFERRED_P (cpu_features, Prefer_No_AVX512));
+  print_cpu_feature_preferred
+    ("mathvec_prefer_no_avx512",
+     CPU_FEATURE_PREFERRED_P (cpu_features, MathVec_Prefer_No_AVX512));
+
+  print_cpu_features_value ("isa_1", cpu_features->isa_1);
+  print_cpu_features_value ("xsave_state_size",
+                            cpu_features->xsave_state_size);
+  print_cpu_features_value ("xsave_state_full_size",
+                            cpu_features->xsave_state_full_size);
+  print_cpu_features_value ("data_cache_size", cpu_features->data_cache_size);
+  print_cpu_features_value ("shared_cache_size",
+                            cpu_features->shared_cache_size);
+  print_cpu_features_value ("non_temporal_threshold",
+                            cpu_features->non_temporal_threshold);
+  print_cpu_features_value ("rep_movsb_threshold",
+                            cpu_features->rep_movsb_threshold);
+  print_cpu_features_value ("rep_movsb_stop_threshold",
+                            cpu_features->rep_movsb_stop_threshold);
+  print_cpu_features_value ("rep_stosb_threshold",
+                            cpu_features->rep_stosb_threshold);
+  print_cpu_features_value ("level1_icache_size",
+                            cpu_features->level1_icache_size);
+  print_cpu_features_value ("level1_dcache_size",
+                            cpu_features->level1_dcache_size);
+  print_cpu_features_value ("level1_dcache_assoc",
+                            cpu_features->level1_dcache_assoc);
+  print_cpu_features_value ("level1_dcache_linesize",
+                            cpu_features->level1_dcache_linesize);
+  print_cpu_features_value ("level2_cache_size",
+                            cpu_features->level2_cache_size);
+  print_cpu_features_value ("level2_cache_assoc",
+                            cpu_features->level2_cache_assoc);
+  print_cpu_features_value ("level2_cache_linesize",
+                            cpu_features->level2_cache_linesize);
+  print_cpu_features_value ("level3_cache_size",
+                            cpu_features->level3_cache_size);
+  print_cpu_features_value ("level3_cache_assoc",
+                            cpu_features->level3_cache_assoc);
+  print_cpu_features_value ("level3_cache_linesize",
+                            cpu_features->level3_cache_linesize);
+  print_cpu_features_value ("level4_cache_size",
+                            cpu_features->level4_cache_size);
+}
diff --git a/sysdeps/x86/include/cpu-features.h b/sysdeps/x86/include/cpu-features.h
index ae5cb24be5..3646150164 100644
--- a/sysdeps/x86/include/cpu-features.h
+++ b/sysdeps/x86/include/cpu-features.h
@@ -772,7 +772,8 @@ enum
 /* EBX.  */
 #define reg_PTWRITE		ebx
 
-/* PREFERRED_FEATURE_INDEX_1.  */
+/* PREFERRED_FEATURE_INDEX_1.  NB: When adding new bits here, update
+   sysdeps/x86/dl-diagnostics-cpu.c.  */
 #define bit_arch_I586				(1u << 0)
 #define bit_arch_I686				(1u << 1)
 #define bit_arch_Fast_Rep_String		(1u << 2)
@@ -856,6 +857,8 @@ struct cpuid_feature_internal
     };
 };
 
+/* NB: When adding new fields, update sysdeps/x86/dl-diagnostics-cpu.c
+   to print them.  */
 struct cpu_features
 {
   struct cpu_features_basic basic;
