diff options
Diffstat (limited to 'm4/ac_have_builtin_expect.m4')
| -rw-r--r-- | m4/ac_have_builtin_expect.m4 | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/m4/ac_have_builtin_expect.m4 b/m4/ac_have_builtin_expect.m4 new file mode 100644 index 000000000000..e91b6fd987ed --- /dev/null +++ b/m4/ac_have_builtin_expect.m4 @@ -0,0 +1,14 @@ +AC_DEFUN([AX_C___BUILTIN_EXPECT], [ + AC_MSG_CHECKING(for __builtin_expect) + AC_CACHE_VAL(ac_cv___builtin_expect, [ + AC_TRY_COMPILE( + [int foo(void) { if (__builtin_expect(0, 0)) return 1; return 0; }], + [], + ac_cv___builtin_expect=yes, + ac_cv___builtin_expect=no + )]) + if test "$ac_cv___builtin_expect" = "yes"; then + AC_DEFINE(HAVE___BUILTIN_EXPECT, 1, [define if your compiler has __builtin_expect]) + fi + AC_MSG_RESULT($ac_cv___builtin_expect) +]) |