From 12f35ada435c0cfab4f62a867186a0b9d61f10e3 Mon Sep 17 00:00:00 2001
From: Elliott Hughes <enh@google.com>
Date: Tue, 2 Dec 2014 20:16:05 -0800
Subject: [PATCH] Switch x86 and x86-64 to __builtin_bswap*.

Bug: 18597513
Change-Id: I0781208efb3b560d7c6fa48f41be7bc6fc83521e
---
 libc/arch-x86/include/machine/endian.h    | 27 ++++------------------
 libc/arch-x86_64/include/machine/endian.h | 28 ++++-------------------
 2 files changed, 8 insertions(+), 47 deletions(-)

diff --git a/libc/arch-x86/include/machine/endian.h b/libc/arch-x86/include/machine/endian.h
index e1506b110..5feebd8d2 100644
--- a/libc/arch-x86/include/machine/endian.h
+++ b/libc/arch-x86/include/machine/endian.h
@@ -27,33 +27,14 @@
 #ifndef _MACHINE_ENDIAN_H_
 #define _MACHINE_ENDIAN_H_
 
-#ifdef __GNUC__
-
-#define	__swap32md(x) __statement({					\
-	uint32_t __swap32md_x = (x);					\
-									\
-	__asm ("bswap %0" : "+r" (__swap32md_x));			\
-	__swap32md_x;							\
-})
-
-#define	__swap64md(x) __statement({					\
-	uint64_t __swap64md_x = (x);					\
-									\
-	(uint64_t)__swap32md(__swap64md_x >> 32) |			\
-	    (uint64_t)__swap32md(__swap64md_x & 0xffffffff) << 32;	\
-})
-#define	__swap16md(x) __statement({					\
-	uint16_t __swap16md_x = (x);					\
-									\
-	__asm ("rorw $8, %w0" : "+r" (__swap16md_x));			\
-	__swap16md_x;							\
-})
+/* Use GCC builtins */
+#define __swap16md(x) __builtin_bswap16(x)
+#define __swap32md(x) __builtin_bswap32(x)
+#define __swap64md(x) __builtin_bswap64(x)
 
 /* Tell sys/endian.h we have MD variants of the swap macros.  */
 #define MD_SWAP
 
-#endif	/* __GNUC__ */
-
 #define _BYTE_ORDER _LITTLE_ENDIAN
 #include <sys/types.h>
 #include <sys/endian.h>
diff --git a/libc/arch-x86_64/include/machine/endian.h b/libc/arch-x86_64/include/machine/endian.h
index 8a3b0c583..2c493b278 100644
--- a/libc/arch-x86_64/include/machine/endian.h
+++ b/libc/arch-x86_64/include/machine/endian.h
@@ -27,34 +27,14 @@
 #ifndef _MACHINE_ENDIAN_H_
 #define _MACHINE_ENDIAN_H_
 
-#ifdef __GNUC__
-
-#define	__swap32md(x) __statement({					\
-	u_int32_t __swap32md_x = (x);					\
-									\
-	__asm ("bswap %0" : "+r" (__swap32md_x));			\
-	__swap32md_x;							\
-})
-
-#define	__swap64md(x) __statement({					\
-	u_int64_t __swap64md_x = (x);					\
-									\
-	__asm ("bswapq %0" : "+r" (__swap64md_x));			\
-	__swap64md_x;							\
-})
-
-#define	__swap16md(x) __statement({					\
-	u_int16_t __swap16md_x = (x);					\
-									\
-	__asm ("rorw $8, %w0" : "+r" (__swap16md_x));			\
-	__swap16md_x;							\
-})
+/* Use GCC builtins */
+#define __swap16md(x) __builtin_bswap16(x)
+#define __swap32md(x) __builtin_bswap32(x)
+#define __swap64md(x) __builtin_bswap64(x)
 
 /* Tell sys/endian.h we have MD variants of the swap macros.  */
 #define MD_SWAP
 
-#endif	/* __GNUC__ */
-
 #define _BYTE_ORDER _LITTLE_ENDIAN
 #include <sys/types.h>
 #include <sys/endian.h>