diff options
Diffstat (limited to 'configure.ac')
| -rw-r--r-- | configure.ac | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/configure.ac b/configure.ac index 968cdb7..bf423d1 100644 --- a/configure.ac +++ b/configure.ac @@ -153,7 +153,21 @@ if test "x$platform" = xposix; then AC_SEARCH_LIBS([pthread_create], [pthread], [test "x$ac_cv_search_pthread_create" != "xnone required" && AC_SUBST(THREAD_LIBS, [-lpthread])], [], []) - AC_SEARCH_LIBS([__atomic_fetch_add_4], [atomic]) + dnl Check for new-style atomic builtins. We first check without linking to -latomic. + AC_MSG_CHECKING(whether __atomic_load_n is supported) + AC_LINK_IFELSE([AC_LANG_SOURCE([[ + #include <stdint.h> + int main() { + struct { + uint64_t *v; + } x; + return (int)__atomic_load_n(x.v, __ATOMIC_ACQUIRE) & + (int)__atomic_add_fetch(x.v, (uint64_t)1, __ATOMIC_ACQ_REL); + }]])], GCC_ATOMIC_BUILTINS_SUPPORTED=yes, GCC_ATOMIC_BUILTINS_SUPPORTED=no) + AC_MSG_RESULT($GCC_ATOMIC_BUILTINS_SUPPORTED) + if test "x$GCC_ATOMIC_BUILTINS_SUPPORTED" != xyes; then + AC_SEARCH_LIBS([__atomic_fetch_add_4], [atomic]) + fi elif test "x$platform" = xwindows; then AC_DEFINE([PLATFORM_WINDOWS], [1], [Define to 1 if compiling for a Windows platform.]) else |