Use __builtin_bswap32/64 in x86_64 <bits/byteswap.h>

diff --git a/ChangeLog b/ChangeLog
index 80b38fc2ac332375e2a21abe4ac96fe5725595b2..d6c9964bebbc0461d93b31242a8406eb71ce331c 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2012-04-10  H.J. Lu  <hongjiu.lu@intel.com>
+
+       * sysdeps/x86_64/bits/byteswap.h: Include <features.h>.
+       (__bswap_32): Use __builtin_bswap32 for GCC >= 4.2.
+       (__bswap_64): Use __builtin_bswap64 for GCC >= 4.2.
+
 2012-04-10  Siddhesh Poyarekar  <siddhesh@redhat.com>
 
        * elf/dl-support.c (_dl_inhibit_cache): New variable.

diff --git a/sysdeps/x86_64/bits/byteswap.h b/sysdeps/x86_64/bits/byteswap.h
index d7e503c6223291920889cdc481d27b6694081fa6..41784393345302f8c897b4d272f58d259451a3bf 100644 (file)
--- a/sysdeps/x86_64/bits/byteswap.h
+++ b/sysdeps/x86_64/bits/byteswap.h
@@ -23,6 +23,7 @@
 #ifndef _BITS_BYTESWAP_H
 #define _BITS_BYTESWAP_H 1
 
+#include <features.h>
 #include <bits/wordsize.h>
 
 /* Swap bytes in 16 bit value.  */
@@ -37,46 +38,60 @@
      ((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >>  8) |                      \
       (((x) & 0x0000ff00) <<  8) | (((x) & 0x000000ff) << 24))
 
-#if defined __GNUC__ && __GNUC__ >= 2
-# if __WORDSIZE == 64 || (defined __i486__ || defined __pentium__            \
-                         || defined __pentiumpro__ || defined __pentium4__   \
-                         || defined __k8__ || defined __athlon__             \
-                         || defined __k6__ || defined __nocona__             \
-                         || defined __core2__ || defined __geode__           \
-                         || defined __amdfam10__)
+#ifdef __GNUC__
+# if __GNUC_PREREQ (4, 2)
+static __inline unsigned int
+__bswap_32 (unsigned int __bsx)
+{
+  return __builtin_bswap32 (__bsx);
+}
+# elif __GNUC__ >= 2
+#  if __WORDSIZE == 64 || (defined __i486__ || defined __pentium__           \
+                          || defined __pentiumpro__ || defined __pentium4__  \
+                          || defined __k8__ || defined __athlon__            \
+                          || defined __k6__ || defined __nocona__            \
+                          || defined __core2__ || defined __geode__          \
+                          || defined __amdfam10__)
 /* To swap the bytes in a word the i486 processors and up provide the
    `bswap' opcode.  On i386 we have to use three instructions.  */
-#  define __bswap_32(x) \
-     (__extension__                                                          \
-      ({ register unsigned int __v, __x = (x);                               \
-        if (__builtin_constant_p (__x))                                      \
-          __v = __bswap_constant_32 (__x);                                   \
-        else                                                                 \
-          __asm__ ("bswap %0" : "=r" (__v) : "0" (__x));                     \
-        __v; }))
+#   define __bswap_32(x) \
+      (__extension__                                                         \
+       ({ register unsigned int __v, __x = (x);                                      \
+         if (__builtin_constant_p (__x))                                     \
+           __v = __bswap_constant_32 (__x);                                  \
+         else                                                                \
+           __asm__ ("bswap %0" : "=r" (__v) : "0" (__x));                    \
+         __v; }))
+#  else
+#   define __bswap_32(x)                                                     \
+      (__extension__                                                         \
+       ({ register unsigned int __v, __x = (x);                                      \
+         if (__builtin_constant_p (__x))                                     \
+           __v = __bswap_constant_32 (__x);                                  \
+         else                                                                \
+           __asm__ ("rorw $8, %w0;"                                          \
+                    "rorl $16, %0;"                                          \
+                    "rorw $8, %w0"                                           \
+                    : "=r" (__v)                                             \
+                    : "0" (__x)                                              \
+                    : "cc");                                                 \
+         __v; }))
+#  endif
 # else
-#  define __bswap_32(x)                                                              \
+#  define __bswap_32(x) \
      (__extension__                                                          \
-      ({ register unsigned int __v, __x = (x);                               \
-        if (__builtin_constant_p (__x))                                      \
-          __v = __bswap_constant_32 (__x);                                   \
-        else                                                                 \
-          __asm__ ("rorw $8, %w0;"                                           \
-                   "rorl $16, %0;"                                           \
-                   "rorw $8, %w0"                                            \
-                   : "=r" (__v)                                              \
-                   : "0" (__x)                                               \
-                   : "cc");                                                  \
-        __v; }))
+      ({ register unsigned int __x = (x); __bswap_constant_32 (__x); }))
 # endif
 #else
-# define __bswap_32(x) \
-     (__extension__                                                          \
-      ({ register unsigned int __x = (x); __bswap_constant_32 (__x); }))
+static __inline unsigned int
+__bswap_32 (unsigned int __bsx)
+{
+  return __bswap_constant_32 (__bsx);
+}
 #endif
 
 
-#if defined __GNUC__ && __GNUC__ >= 2
+#if __GNUC_PREREQ (2, 0)
 /* Swap bytes in 64 bit value.  */
 # define __bswap_constant_64(x) \
      (__extension__ ((((x) & 0xff00000000000000ull) >> 56)                   \
@@ -88,7 +103,13 @@
                     | (((x) & 0x000000000000ff00ull) << 40)                  \
                     | (((x) & 0x00000000000000ffull) << 56)))
 
-# if __WORDSIZE == 64
+# if __GNUC_PREREQ (4, 2)
+static __inline unsigned long long int
+__bswap_64 (unsigned long long int __bsx)
+{
+  return __builtin_bswap64 (__bsx);
+}
+# elif __WORDSIZE == 64
 #  define __bswap_64(x) \
      (__extension__                                                          \
       ({ register unsigned long __v, __x = (x);                                      \