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-rw-r--r--gl/m4/builtin-expect.m449
1 files changed, 49 insertions, 0 deletions
diff --git a/gl/m4/builtin-expect.m4 b/gl/m4/builtin-expect.m4
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1dnl Check for __builtin_expect.
2
3dnl Copyright 2016-2023 Free Software Foundation, Inc.
4dnl This file is free software; the Free Software Foundation
5dnl gives unlimited permission to copy and/or distribute it,
6dnl with or without modifications, as long as this notice is preserved.
7
8dnl Written by Paul Eggert.
9
10AC_DEFUN([gl___BUILTIN_EXPECT],
11[
12 AC_CACHE_CHECK([for __builtin_expect],
13 [gl_cv___builtin_expect],
14 [AC_LINK_IFELSE(
15 [AC_LANG_SOURCE([[
16 int
17 main (int argc, char **argv)
18 {
19 argc = __builtin_expect (argc, 100);
20 return argv[argc != 100][0];
21 }]])],
22 [gl_cv___builtin_expect=yes],
23 [AC_LINK_IFELSE(
24 [AC_LANG_SOURCE([[
25 #include <builtins.h>
26 int
27 main (int argc, char **argv)
28 {
29 argc = __builtin_expect (argc, 100);
30 return argv[argc != 100][0];
31 }]])],
32 [gl_cv___builtin_expect="in <builtins.h>"],
33 [gl_cv___builtin_expect=no])])])
34 if test "$gl_cv___builtin_expect" = yes; then
35 AC_DEFINE([HAVE___BUILTIN_EXPECT], [1])
36 elif test "$gl_cv___builtin_expect" = "in <builtins.h>"; then
37 AC_DEFINE([HAVE___BUILTIN_EXPECT], [2])
38 fi
39 AH_VERBATIM([HAVE___BUILTIN_EXPECT],
40 [/* Define to 1 if the compiler supports __builtin_expect,
41 and to 2 if <builtins.h> does. */
42#undef HAVE___BUILTIN_EXPECT
43#ifndef HAVE___BUILTIN_EXPECT
44# define __builtin_expect(e, c) (e)
45#elif HAVE___BUILTIN_EXPECT == 2
46# include <builtins.h>
47#endif
48 ])
49])