From: Omri Mor <omor1@asu.edu>
Date: Sun, 30 Apr 2017 22:25:06 +0000 (-0700)
Subject: os/os-linux.h: fix broken byte swap intrinsics
X-Git-Tag: fio-2.20~26^2
X-Git-Url: https://git.kernel.dk/?p=fio.git;a=commitdiff_plain;h=7922a7b75ea9f5cdc7505bb98bbed100d3e3d124

os/os-linux.h: fix broken byte swap intrinsics

Signed-off-by: Omri Mor <omor1@asu.edu>
---

diff --git a/os/os-linux.h b/os/os-linux.h
index 7b328dc0..911f7e7c 100644
--- a/os/os-linux.h
+++ b/os/os-linux.h
@@ -16,12 +16,15 @@
 #include <linux/unistd.h>
 #include <linux/raw.h>
 #include <linux/major.h>
-#include <byteswap.h>
 
 #include "./os-linux-syscall.h"
 #include "binject.h"
 #include "../file.h"
 
+#ifndef __has_builtin         // Optional of course.
+  #define __has_builtin(x) 0  // Compatibility with non-clang compilers.
+#endif
+
 #define FIO_HAVE_CPU_AFFINITY
 #define FIO_HAVE_DISK_UTIL
 #define FIO_HAVE_SGIO
@@ -219,21 +222,19 @@ static inline int fio_lookup_raw(dev_t dev, int *majdev, int *mindev)
 #define FIO_MADV_FREE	MADV_REMOVE
 #endif
 
-#if defined(__builtin_bswap16)
+/* Check for GCC or Clang byte swap intrinsics */
+#if (__has_builtin(__builtin_bswap16) && __has_builtin(__builtin_bswap32) \
+     && __has_builtin(__builtin_bswap64)) || (__GNUC__ > 4 \
+     || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)) /* fio_swapN */
 #define fio_swap16(x)	__builtin_bswap16(x)
-#else
-#define fio_swap16(x)	__bswap_16(x)
-#endif
-#if defined(__builtin_bswap32)
 #define fio_swap32(x)	__builtin_bswap32(x)
-#else
-#define fio_swap32(x)	__bswap_32(x)
-#endif
-#if defined(__builtin_bswap64)
 #define fio_swap64(x)	__builtin_bswap64(x)
 #else
-#define fio_swap64(x)	__bswap_64(x)
-#endif
+#include <byteswap.h>
+#define fio_swap16(x)	bswap_16(x)
+#define fio_swap32(x)	bswap_32(x)
+#define fio_swap64(x)	bswap_64(x)
+#endif /* fio_swapN */
 
 #define CACHE_LINE_FILE	\
 	"/sys/devices/system/cpu/cpu0/cache/index0/coherency_line_size"