| dnl Check for __builtin_expect. |
| |
| dnl Copyright 2016-2021 Free Software Foundation, Inc. |
| dnl This file is free software; the Free Software Foundation |
| dnl gives unlimited permission to copy and/or distribute it, |
| dnl with or without modifications, as long as this notice is preserved. |
| |
| dnl Written by Paul Eggert. |
| |
| AC_DEFUN([gl___BUILTIN_EXPECT], |
| [ |
| AC_CACHE_CHECK([for __builtin_expect], |
| [gl_cv___builtin_expect], |
| [AC_LINK_IFELSE( |
| [AC_LANG_SOURCE([[ |
| int |
| main (int argc, char **argv) |
| { |
| argc = __builtin_expect (argc, 100); |
| return argv[argc != 100][0]; |
| }]])], |
| [gl_cv___builtin_expect=yes], |
| [AC_LINK_IFELSE( |
| [AC_LANG_SOURCE([[ |
| #include <builtins.h> |
| int |
| main (int argc, char **argv) |
| { |
| argc = __builtin_expect (argc, 100); |
| return argv[argc != 100][0]; |
| }]])], |
| [gl_cv___builtin_expect="in <builtins.h>"], |
| [gl_cv___builtin_expect=no])])]) |
| if test "$gl_cv___builtin_expect" = yes; then |
| AC_DEFINE([HAVE___BUILTIN_EXPECT], [1]) |
| elif test "$gl_cv___builtin_expect" = "in <builtins.h>"; then |
| AC_DEFINE([HAVE___BUILTIN_EXPECT], [2]) |
| fi |
| AH_VERBATIM([HAVE___BUILTIN_EXPECT], |
| [/* Define to 1 if the compiler supports __builtin_expect, |
| and to 2 if <builtins.h> does. */ |
| #undef HAVE___BUILTIN_EXPECT |
| #ifndef HAVE___BUILTIN_EXPECT |
| # define __builtin_expect(e, c) (e) |
| #elif HAVE___BUILTIN_EXPECT == 2 |
| # include <builtins.h> |
| #endif |
| ]) |
| ]) |
