diff options
Diffstat (limited to 'configure.in')
| -rw-r--r-- | configure.in | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/configure.in b/configure.in index d256af08da..40d9f55a16 100644 --- a/configure.in +++ b/configure.in @@ -987,6 +987,28 @@ static) ;; esac +dnl Check whether compiler understands __builtin_expect. +AC_CACHE_CHECK(for __builtin_expect, libc_cv_gcc_builtin_expect, +[cat > conftest.c <<EOF +#line __oline__ "configure" +int foo (int a) +{ + a = __builtin_expect (a, 10); + return a == 10 ? 0 : 1; +} +EOF +dnl No \ in command here because it ends up inside ''. +if AC_TRY_COMMAND([${CC-cc} $CFLAGS -nostdlib -nostartfiles + -o conftest conftest.c -lgcc >&AC_FD_CC]); then + libc_cv_gcc_builtin_expect=yes +else + libc_cv_gcc_builtin_expect=no +fi +rm -f conftest*]) +if test "$libc_cv_gcc_builtin_expect" = yes; then + AC_DEFINE(HAVE_BUILTIN_EXPECT) +fi + ### End of automated tests. ### Now run sysdeps configure fragments. |