From: Dennis Ameling <dennis@xxxxxxxxxxxxxxxxx> Newer compiler versions, like GCC 10 and Clang 12, have built-in functions for bswap32 and bswap64. This comes in handy, for example, when targeting CLANGARM64 on Windows, which would not be supported without this logic. Signed-off-by: Dennis Ameling <dennis@xxxxxxxxxxxxxxxxx> --- compat/bswap.h | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/compat/bswap.h b/compat/bswap.h index b34054f2bd7..9e0f98e00b9 100644 --- a/compat/bswap.h +++ b/compat/bswap.h @@ -35,7 +35,19 @@ static inline uint64_t default_bswap64(uint64_t val) #undef bswap32 #undef bswap64 -#if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)) +/** + * __has_builtin is available since Clang 10 and GCC 10. + * Below is a fallback for older compilers. + */ +#ifndef __has_builtin + #define __has_builtin(x) 0 +#endif + +#if __has_builtin(__builtin_bswap32) && __has_builtin(__builtin_bswap64) +#define bswap32(x) __builtin_bswap32((x)) +#define bswap64(x) __builtin_bswap64((x)) + +#elif defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)) #define bswap32 git_bswap32 static inline uint32_t git_bswap32(uint32_t x) -- gitgitgadget
