m4/ax_gcc_builtin.m4

   1 # ===========================================================================
   2 #      http://www.gnu.org/software/autoconf-archive/ax_gcc_builtin.html
   3 # ===========================================================================
   4 #
   5 # SYNOPSIS
   6 #
   7 #   AX_GCC_BUILTIN(BUILTIN)
   8 #
   9 # DESCRIPTION
  10 #
  11 #   This macro checks if the compiler supports one of GCC's built-in
  12 #   functions; many other compilers also provide those same built-ins.
  13 #
  14 #   The BUILTIN parameter is the name of the built-in function.
  15 #
  16 #   If BUILTIN is supported define HAVE_<BUILTIN>. Keep in mind that since
  17 #   builtins usually start with two underscores they will be copied over
  18 #   into the HAVE_<BUILTIN> definition (e.g. HAVE___BUILTIN_EXPECT for
  19 #   __builtin_expect()).
  20 #
  21 #   The macro caches its result in the ax_cv_have_<BUILTIN> variable (e.g.
  22 #   ax_cv_have___builtin_expect).
  23 #
  24 #   The macro currently supports the following built-in functions:
  25 #
  26 #    __builtin_assume_aligned
  27 #    __builtin_bswap32
  28 #    __builtin_bswap64
  29 #    __builtin_choose_expr
  30 #    __builtin___clear_cache
  31 #    __builtin_clrsb
  32 #    __builtin_clrsbl
  33 #    __builtin_clrsbll
  34 #    __builtin_clz
  35 #    __builtin_clzl
  36 #    __builtin_clzll
  37 #    __builtin_complex
  38 #    __builtin_constant_p
  39 #    __builtin_ctz
  40 #    __builtin_ctzl
  41 #    __builtin_ctzll
  42 #    __builtin_expect
  43 #    __builtin_ffs
  44 #    __builtin_ffsl
  45 #    __builtin_ffsll
  46 #    __builtin_fpclassify
  47 #    __builtin_huge_val
  48 #    __builtin_huge_valf
  49 #    __builtin_huge_vall
  50 #    __builtin_inf
  51 #    __builtin_infd128
  52 #    __builtin_infd32
  53 #    __builtin_infd64
  54 #    __builtin_inff
  55 #    __builtin_infl
  56 #    __builtin_isinf_sign
  57 #    __builtin_nan
  58 #    __builtin_nand128
  59 #    __builtin_nand32
  60 #    __builtin_nand64
  61 #    __builtin_nanf
  62 #    __builtin_nanl
  63 #    __builtin_nans
  64 #    __builtin_nansf
  65 #    __builtin_nansl
  66 #    __builtin_object_size
  67 #    __builtin_parity
  68 #    __builtin_parityl
  69 #    __builtin_parityll
  70 #    __builtin_popcount
  71 #    __builtin_popcountl
  72 #    __builtin_popcountll
  73 #    __builtin_powi
  74 #    __builtin_powif
  75 #    __builtin_powil
  76 #    __builtin_prefetch
  77 #    __builtin_trap
  78 #    __builtin_types_compatible_p
  79 #    __builtin_unreachable
  80 #
  81 #   Unsuppored built-ins will be tested with an empty parameter set and the
  82 #   result of the check might be wrong or meaningless so use with care.
  83 #
  84 # LICENSE
  85 #
  86 #   Copyright (c) 2013 Gabriele Svelto <gabriele.svelto@gmail.com>
  87 #
  88 #   Copying and distribution of this file, with or without modification, are
  89 #   permitted in any medium without royalty provided the copyright notice
  90 #   and this notice are preserved.  This file is offered as-is, without any
  91 #   warranty.
  92
  93 #serial 2
  94
  95 AC_DEFUN([AX_GCC_BUILTIN], [
  96     AS_VAR_PUSHDEF([ac_var], [ax_cv_have_$1])
  97
  98     AC_CACHE_CHECK([for $1], [ac_var], [
  99         AC_LINK_IFELSE([AC_LANG_PROGRAM([], [
 100             m4_case([$1],
 101                 [__builtin_assume_aligned], [$1("", 0)],
 102                 [__builtin_bswap32], [$1(0)],
 103                 [__builtin_bswap64], [$1(0)],
 104                 [__builtin_choose_expr], [$1(0, 0, 0)],
 105                 [__builtin___clear_cache], [$1("", "")],
 106                 [__builtin_clrsb], [$1(0)],
 107                 [__builtin_clrsbl], [$1(0)],
 108                 [__builtin_clrsbll], [$1(0)],
 109                 [__builtin_clz], [$1(0)],
 110                 [__builtin_clzl], [$1(0)],
 111                 [__builtin_clzll], [$1(0)],
 112                 [__builtin_complex], [$1(0.0, 0.0)],
 113                 [__builtin_constant_p], [$1(0)],
 114                 [__builtin_ctz], [$1(0)],
 115                 [__builtin_ctzl], [$1(0)],
 116                 [__builtin_ctzll], [$1(0)],
 117                 [__builtin_expect], [$1(0, 0)],
 118                 [__builtin_ffs], [$1(0)],
 119                 [__builtin_ffsl], [$1(0)],
 120                 [__builtin_ffsll], [$1(0)],
 121                 [__builtin_fpclassify], [$1(0, 1, 2, 3, 4, 0.0)],
 122                 [__builtin_huge_val], [$1()],
 123                 [__builtin_huge_valf], [$1()],
 124                 [__builtin_huge_vall], [$1()],
 125                 [__builtin_inf], [$1()],
 126                 [__builtin_infd128], [$1()],
 127                 [__builtin_infd32], [$1()],
 128                 [__builtin_infd64], [$1()],
 129                 [__builtin_inff], [$1()],
 130                 [__builtin_infl], [$1()],
 131                 [__builtin_isinf_sign], [$1(0.0)],
 132                 [__builtin_nan], [$1("")],
 133                 [__builtin_nand128], [$1("")],
 134                 [__builtin_nand32], [$1("")],
 135                 [__builtin_nand64], [$1("")],
 136                 [__builtin_nanf], [$1("")],
 137                 [__builtin_nanl], [$1("")],
 138                 [__builtin_nans], [$1("")],
 139                 [__builtin_nansf], [$1("")],
 140                 [__builtin_nansl], [$1("")],
 141                 [__builtin_object_size], [$1("", 0)],
 142                 [__builtin_parity], [$1(0)],
 143                 [__builtin_parityl], [$1(0)],
 144                 [__builtin_parityll], [$1(0)],
 145                 [__builtin_popcount], [$1(0)],
 146                 [__builtin_popcountl], [$1(0)],
 147                 [__builtin_popcountll], [$1(0)],
 148                 [__builtin_powi], [$1(0, 0)],
 149                 [__builtin_powif], [$1(0, 0)],
 150                 [__builtin_powil], [$1(0, 0)],
 151                 [__builtin_prefetch], [$1("")],
 152                 [__builtin_trap], [$1()],
 153                 [__builtin_types_compatible_p], [$1(int, int)],
 154                 [__builtin_unreachable], [$1()],
 155                 [m4_warn([syntax], [Unsupported built-in $1, the test may fail])
 156                  $1()]
 157             )
 158             ])],
 159             [AS_VAR_SET([ac_var], [yes])],
 160             [AS_VAR_SET([ac_var], [no])])
 161     ])
 162
 163     AS_IF([test yes = AS_VAR_GET([ac_var])],
 164         [AC_DEFINE_UNQUOTED(AS_TR_CPP(HAVE_$1), 1,
 165             [Define to 1 if the system has the `$1' built-in function])], [])
 166
 167     AS_VAR_POPDEF([ac_var])
 168 ])