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dnl Check for __builtin_expect. |
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dnl Copyright 2016-2023 Free Software Foundation, Inc. |
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dnl This file is free software; the Free Software Foundation |
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dnl gives unlimited permission to copy and/or distribute it, |
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dnl with or without modifications, as long as this notice is preserved. |
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dnl Written by Paul Eggert. |
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AC_DEFUN([gl___BUILTIN_EXPECT], |
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[ |
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AC_CACHE_CHECK([for __builtin_expect], |
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[gl_cv___builtin_expect], |
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[AC_LINK_IFELSE( |
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[AC_LANG_SOURCE([[ |
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int |
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main (int argc, char **argv) |
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{ |
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argc = __builtin_expect (argc, 100); |
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return argv[argc != 100][0]; |
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}]])], |
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[gl_cv___builtin_expect=yes], |
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[AC_LINK_IFELSE( |
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[AC_LANG_SOURCE([[ |
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#include <builtins.h> |
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int |
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main (int argc, char **argv) |
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{ |
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argc = __builtin_expect (argc, 100); |
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return argv[argc != 100][0]; |
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}]])], |
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[gl_cv___builtin_expect="in <builtins.h>"], |
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[gl_cv___builtin_expect=no])])]) |
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if test "$gl_cv___builtin_expect" = yes; then |
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AC_DEFINE([HAVE___BUILTIN_EXPECT], [1]) |
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elif test "$gl_cv___builtin_expect" = "in <builtins.h>"; then |
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AC_DEFINE([HAVE___BUILTIN_EXPECT], [2]) |
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fi |
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AH_VERBATIM([HAVE___BUILTIN_EXPECT], |
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[ |
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and to 2 if <builtins.h> does. */ |
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#undef HAVE___BUILTIN_EXPECT |
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#ifndef HAVE___BUILTIN_EXPECT |
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# define __builtin_expect(e, c) (e) |
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#elif HAVE___BUILTIN_EXPECT == 2 |
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# include <builtins.h> |
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#endif |
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]) |
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]) |
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