System: Add SwapByteOrder and update Support/MathExtras.h to use it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116234 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 31 deletions

diff --git a/include/llvm/Support/MathExtras.h b/include/llvm/Support/MathExtras.h
index 982813f718..3b907808dd 100644
--- a/include/llvm/Support/MathExtras.h
+++ b/include/llvm/Support/MathExtras.h
@@ -15,6 +15,7 @@
 #define LLVM_SUPPORT_MATHEXTRAS_H
 
 #include "llvm/System/DataTypes.h"
+#include "llvm/System/SwapByteOrder.h"
 
 namespace llvm {
 
@@ -112,47 +113,19 @@ inline bool isPowerOf2_64(uint64_t Value) {
 /// ByteSwap_16 - This function returns a byte-swapped representation of the
 /// 16-bit argument, Value.
 inline uint16_t ByteSwap_16(uint16_t Value) {
-#if defined(_MSC_VER) && !defined(_DEBUG)
-  // The DLL version of the runtime lacks these functions (bug!?), but in a
-  // release build they're replaced with BSWAP instructions anyway.
-  return _byteswap_ushort(Value);
-#else
-  uint16_t Hi = Value << 8;
-  uint16_t Lo = Value >> 8;
-  return Hi | Lo;
-#endif
+  return sys::SwapByteOrder(Value);
 }
 
 /// ByteSwap_32 - This function returns a byte-swapped representation of the
 /// 32-bit argument, Value.
 inline uint32_t ByteSwap_32(uint32_t Value) {
-#if defined(__llvm__) || \
-    (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)) && !defined(__ICC)
-  return __builtin_bswap32(Value);
-#elif defined(_MSC_VER) && !defined(_DEBUG)
-  return _byteswap_ulong(Value);
-#else
-  uint32_t Byte0 = Value & 0x000000FF;
-  uint32_t Byte1 = Value & 0x0000FF00;
-  uint32_t Byte2 = Value & 0x00FF0000;
-  uint32_t Byte3 = Value & 0xFF000000;
-  return (Byte0 << 24) | (Byte1 << 8) | (Byte2 >> 8) | (Byte3 >> 24);
-#endif
+  return sys::SwapByteOrder(Value);
 }
 
 /// ByteSwap_64 - This function returns a byte-swapped representation of the
 /// 64-bit argument, Value.
 inline uint64_t ByteSwap_64(uint64_t Value) {
-#if defined(__llvm__) || \
-    (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)) && !defined(__ICC)
-  return __builtin_bswap64(Value);
-#elif defined(_MSC_VER) && !defined(_DEBUG)
-  return _byteswap_uint64(Value);
-#else
-  uint64_t Hi = ByteSwap_32(uint32_t(Value));
-  uint32_t Lo = ByteSwap_32(uint32_t(Value >> 32));
-  return (Hi << 32) | Lo;
-#endif
+  return sys::SwapByteOrder(Value);
 }
 
 /// CountLeadingZeros_32 - this function performs the platform optimal form of