| AC_DEFUN([DISPATCH_C_ATOMIC_BUILTINS], [ |
| # |
| # This is a bit subtle: on i386 systems without at least -march=i486 defined, |
| # certain built-in atomics fall back to depending on undefined symbols if |
| # their return values are used. |
| # |
| AC_CACHE_CHECK([for gcc atomic builtins],[dispatch_cv_atomic], |
| [AC_LINK_IFELSE([AC_LANG_PROGRAM([],[[ |
| int i, x =0; |
| i = __sync_add_and_fetch(&x,1); |
| return x;]])],[dispatch_cv_atomic=yes], |
| [saveCFLAGS="$CFLAGS" |
| CFLAGS="$CFLAGS -march=i486" |
| AC_LINK_IFELSE([AC_LANG_PROGRAM([],[[ |
| int i, x =0; |
| i = __sync_add_and_fetch(&x,1); |
| return x;]])],[CFLAGS="$saveCFLAGS" |
| dispatch_cv_atomic="-march=i486" |
| ])])]) |
| |
| ]) |
