Merge pull request #1056 from ranma42/vc-compat-C90

[mono.git] / libgc / configure.in

diff --git a/libgc/configure.in b/libgc/configure.in
index be6f6d4259bba4cd59761a84fad03adea161cf47..837e2cb9f158c14f8cdbe47e0abc14091db14edf 100644 (file)
--- a/libgc/configure.in
+++ b/libgc/configure.in
@@ -217,6 +217,22 @@ case "$host" in
 esac
 AM_CONDITIONAL(POWERPC_DARWIN,test x$powerpc_darwin = xtrue)
 
+# Check if the GCC builtin __sync_bool_compare_and_swap is available.
+# It is preferred in gc_locks.h for PPC as GCC 4.4 has a problem with the inline assembly there.
+AC_MSG_CHECKING(for __sync_bool_compare_and_swap)
+AC_TRY_COMPILE([],[
+volatile unsigned int foo = 0;
+int main(int argc, char** argv) {
+    unsigned int r1 = __sync_bool_compare_and_swap(&foo, 0, 1);
+    return 0;
+}
+], [
+AC_MSG_RESULT(yes)
+AC_DEFINE(HAS___SYNC_BOOL_COMPARE_AND_SWAP)
+], [
+AC_MSG_RESULT(no)
+])
+
 AC_MSG_CHECKING(for xlc)
 AC_TRY_COMPILE([],[
  #ifndef __xlC__