util/u_atomic: provide 64bit atomics where they're missing

[mesa.git] / configure.ac

diff --git a/configure.ac b/configure.ac
index 016e38fb5998e485332feed42679b1974ef382e9..83cd5d1d15eae094445411387958210e7a2202b2 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -415,6 +415,20 @@ if test "x$GCC_ATOMIC_BUILTINS_SUPPORTED" = x1; then
 fi
 AM_CONDITIONAL([GCC_ATOMIC_BUILTINS_SUPPORTED], [test x$GCC_ATOMIC_BUILTINS_SUPPORTED = x1])
 
+dnl Check if host supports 64-bit atomics
+dnl note that lack of support usually results in link (not compile) error
+AC_MSG_CHECKING(whether __sync_add_and_fetch_8 is supported)
+AC_LINK_IFELSE([AC_LANG_SOURCE([[
+#include <stdint.h>
+uint64_t v;
+int main() {
+    return __sync_add_and_fetch(&v, (uint64_t)1);
+}]])], GCC_64BIT_ATOMICS_SUPPORTED=yes, GCC_64BIT_ATOMICS_SUPPORTED=no)
+if test "x$GCC_64BIT_ATOMICS_SUPPORTED" != xyes; then
+    DEFINES="$DEFINES -DMISSING_64BIT_ATOMICS"
+fi
+AC_MSG_RESULT($GCC_64BIT_ATOMICS_SUPPORTED)
+
 dnl Check for Endianness
 AC_C_BIGENDIAN(
    little_endian=no,