libgfortran/acinclude.m4

   1 m4_include(../config/acx.m4)
   2 m4_include(../config/no-executables.m4)
   3 m4_include(../config/math.m4)
   4 m4_include(../config/ax_check_define.m4)
   5 m4_include(../config/enable.m4)
   6 m4_include(../config/cet.m4)
   7
   8 dnl Check that we have a working GNU Fortran compiler
   9 AC_DEFUN([LIBGFOR_WORKING_GFORTRAN], [
  10 AC_MSG_CHECKING([whether the GNU Fortran compiler is working])
  11 AC_LANG_PUSH([Fortran])
  12 AC_COMPILE_IFELSE([[
  13       program foo
  14       real, parameter :: bar = sin (12.34 / 2.5)
  15       end program foo]],
  16     [AC_MSG_RESULT([yes])],
  17     [AC_MSG_RESULT([no])
  18      AC_MSG_ERROR([GNU Fortran is not working; please report a bug in http://gcc.gnu.org/bugzilla, attaching $PWD/config.log])
  19     ])
  20 AC_LANG_POP([Fortran])
  21 ])
  22
  23
  24 sinclude(../libtool.m4)
  25 dnl The lines below arrange for aclocal not to bring an installed
  26 dnl libtool.m4 into aclocal.m4, while still arranging for automake to
  27 dnl add a definition of LIBTOOL to Makefile.in.
  28 ifelse(,,,[AC_SUBST(LIBTOOL)
  29 AC_DEFUN([AM_PROG_LIBTOOL])
  30 AC_DEFUN([AC_LIBTOOL_DLOPEN])
  31 AC_DEFUN([AC_PROG_LD])
  32 ])
  33
  34 dnl Check whether the target supports hidden visibility.
  35 AC_DEFUN([LIBGFOR_CHECK_ATTRIBUTE_VISIBILITY], [
  36   AC_CACHE_CHECK([whether the target supports hidden visibility],
  37                  libgfor_cv_have_attribute_visibility, [
  38   save_CFLAGS="$CFLAGS"
  39   CFLAGS="$CFLAGS -Werror"
  40   AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[void __attribute__((visibility("hidden"))) foo(void) { }]], [])],
  41                     libgfor_cv_have_attribute_visibility=yes,
  42                     libgfor_cv_have_attribute_visibility=no)
  43   CFLAGS="$save_CFLAGS"])
  44   if test $libgfor_cv_have_attribute_visibility = yes; then
  45     AC_DEFINE(HAVE_ATTRIBUTE_VISIBILITY, 1,
  46       [Define to 1 if the target supports __attribute__((visibility(...))).])
  47   fi])
  48
  49 dnl Check whether the target supports symbol aliases.
  50 AC_DEFUN([LIBGFOR_CHECK_ATTRIBUTE_ALIAS], [
  51   AC_CACHE_CHECK([whether the target supports symbol aliases],
  52                  libgfor_cv_have_attribute_alias, [
  53   AC_LINK_IFELSE([AC_LANG_PROGRAM([[
  54 void foo(void) { }
  55 extern void bar(void) __attribute__((alias("foo")));]],
  56     [[bar();]])], libgfor_cv_have_attribute_alias=yes, libgfor_cv_have_attribute_alias=no)])
  57   if test $libgfor_cv_have_attribute_alias = yes; then
  58     AC_DEFINE(HAVE_ATTRIBUTE_ALIAS, 1,
  59       [Define to 1 if the target supports __attribute__((alias(...))).])
  60   fi])
  61
  62 dnl Check whether the target supports __atomic_fetch_add.
  63 AC_DEFUN([LIBGFOR_CHECK_ATOMIC_FETCH_ADD], [
  64   AC_CACHE_CHECK([whether the target supports __atomic_fetch_add],
  65                  libgfor_cv_have_atomic_fetch_add, [
  66   AC_LINK_IFELSE([AC_LANG_PROGRAM([[int foovar = 0;]], [[
  67 if (foovar <= 0) return __atomic_fetch_add (&foovar, 1, __ATOMIC_ACQ_REL);
  68 if (foovar > 10) return __atomic_add_fetch (&foovar, -1, __ATOMIC_ACQ_REL);]])],
  69               libgfor_cv_have_atomic_fetch_add=yes, libgfor_cv_have_atomic_fetch_add=no)])
  70   if test $libgfor_cv_have_atomic_fetch_add = yes; then
  71     AC_DEFINE(HAVE_ATOMIC_FETCH_ADD, 1,
  72               [Define to 1 if the target supports __atomic_fetch_add])
  73   fi])
  74
  75 dnl Check for pragma weak.
  76 AC_DEFUN([LIBGFOR_GTHREAD_WEAK], [
  77   AC_CACHE_CHECK([whether pragma weak works],
  78                  libgfor_cv_have_pragma_weak, [
  79   gfor_save_CFLAGS="$CFLAGS"
  80   CFLAGS="$CFLAGS -Wunknown-pragmas"
  81   AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
  82 void foo (void);
  83 #pragma weak foo
  84 ]], [[if (foo) foo ();]])],
  85                     libgfor_cv_have_pragma_weak=yes, libgfor_cv_have_pragma_weak=no)])
  86   if test $libgfor_cv_have_pragma_weak = yes; then
  87     AC_DEFINE(SUPPORTS_WEAK, 1,
  88               [Define to 1 if the target supports #pragma weak])
  89   fi
  90   case "$host" in
  91     *-*-darwin* | *-*-hpux* | *-*-cygwin* | *-*-mingw* | *-*-musl* )
  92       AC_DEFINE(GTHREAD_USE_WEAK, 0,
  93                 [Define to 0 if the target shouldn't use #pragma weak])
  94       ;;
  95   esac])
  96
  97 dnl Check whether target effectively supports weakref
  98 AC_DEFUN([LIBGFOR_CHECK_WEAKREF], [
  99   AC_CACHE_CHECK([whether the target supports weakref],
 100                  libgfor_cv_have_weakref, [
 101   save_CFLAGS="$CFLAGS"
 102   CFLAGS="$CFLAGS -Wunknown-pragmas -Werror"
 103   AC_LINK_IFELSE([AC_LANG_PROGRAM([[
 104 static int mytoto (int) __attribute__((__weakref__("toto")));
 105 ]], [[return (mytoto != 0);]])],
 106                  libgfor_cv_have_weakref=yes, libgfor_cv_have_weakref=no)
 107   CFLAGS="$save_CFLAGS"])
 108   if test $libgfor_cv_have_weakref = yes; then
 109     AC_DEFINE(SUPPORTS_WEAKREF, 1,
 110               [Define to 1 if the target supports weakref])
 111   fi])
 112
 113 dnl Check whether target can unlink a file still open.
 114 AC_DEFUN([LIBGFOR_CHECK_UNLINK_OPEN_FILE], [
 115   AC_CACHE_CHECK([whether the target can unlink an open file],
 116                   libgfor_cv_have_unlink_open_file, [
 117   AC_RUN_IFELSE([AC_LANG_SOURCE([[
 118 #include <errno.h>
 119 #include <fcntl.h>
 120 #include <unistd.h>
 121 #include <sys/stat.h>
 122
 123 int main ()
 124 {
 125   int fd;
 126
 127   fd = open ("testfile", O_RDWR | O_CREAT, S_IWUSR | S_IRUSR);
 128   if (fd <= 0)
 129     return 0;
 130   if (unlink ("testfile") == -1)
 131     return 1;
 132   write (fd, "This is a test\n", 15);
 133   close (fd);
 134
 135   if (open ("testfile", O_RDONLY) == -1 && errno == ENOENT)
 136     return 0;
 137   else
 138     return 1;
 139 }]])], libgfor_cv_have_unlink_open_file=yes, libgfor_cv_have_unlink_open_file=no, [
 140 case "${target}" in
 141   *mingw*) libgfor_cv_have_unlink_open_file=no ;;
 142   *) libgfor_cv_have_unlink_open_file=yes;;
 143 esac])])
 144 if test x"$libgfor_cv_have_unlink_open_file" = xyes; then
 145   AC_DEFINE(HAVE_UNLINK_OPEN_FILE, 1, [Define if target can unlink open files.])
 146 fi])
 147
 148 dnl Check whether CRLF is the line terminator
 149 AC_DEFUN([LIBGFOR_CHECK_CRLF], [
 150   AC_CACHE_CHECK([whether the target has CRLF as line terminator],
 151                   libgfor_cv_have_crlf, [
 152   AC_RUN_IFELSE([AC_LANG_SOURCE([[
 153 /* This test program should exit with status 0 if system uses a CRLF as
 154    line terminator, and status 1 otherwise.
 155    Since it is used to check for mingw systems, and should return 0 in any
 156    other case, in case of a failure we will not use CRLF.  */
 157 #include <sys/stat.h>
 158 #include <stdlib.h>
 159 #include <fcntl.h>
 160 #include <stdio.h>
 161
 162 int main ()
 163 {
 164 #ifndef O_BINARY
 165   exit(1);
 166 #else
 167   int fd, bytes;
 168   char buff[5];
 169
 170   fd = open ("foo", O_WRONLY | O_CREAT | O_TRUNC, S_IRWXU);
 171   if (fd < 0)
 172     exit(1);
 173   if (write (fd, "\n", 1) < 0)
 174     perror ("write");
 175
 176   close (fd);
 177
 178   if ((fd = open ("foo", O_RDONLY | O_BINARY, S_IRWXU)) < 0)
 179     exit(1);
 180   bytes = read (fd, buff, 5);
 181   if (bytes == 2 && buff[0] == '\r' && buff[1] == '\n')
 182     exit(0);
 183   else
 184     exit(1);
 185 #endif
 186 }]])], libgfor_cv_have_crlf=yes, libgfor_cv_have_crlf=no, [
 187 case "${target}" in
 188   *mingw*) libgfor_cv_have_crlf=yes ;;
 189   *) libgfor_cv_have_crlf=no;;
 190 esac])])
 191 if test x"$libgfor_cv_have_crlf" = xyes; then
 192   AC_DEFINE(HAVE_CRLF, 1, [Define if CRLF is line terminator.])
 193 fi])
 194
 195 dnl Check whether the st_ino and st_dev stat fields taken together uniquely
 196 dnl identify the file within the system. This is should be true for POSIX
 197 dnl systems; it is known to be false on mingw32.
 198 AC_DEFUN([LIBGFOR_CHECK_WORKING_STAT], [
 199   AC_CACHE_CHECK([whether the target stat is reliable],
 200                   libgfor_cv_have_working_stat, [
 201   AC_RUN_IFELSE([AC_LANG_SOURCE([[
 202 #include <stdio.h>
 203 #include <sys/types.h>
 204 #include <sys/stat.h>
 205 #include <unistd.h>
 206
 207 int main ()
 208 {
 209   FILE *f, *g;
 210   struct stat st1, st2;
 211
 212   f = fopen ("foo", "w");
 213   g = fopen ("bar", "w");
 214   if (stat ("foo", &st1) != 0 || stat ("bar", &st2))
 215     return 1;
 216   if (st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino)
 217     return 1;
 218   fclose(f);
 219   fclose(g);
 220   return 0;
 221 }]])], libgfor_cv_have_working_stat=yes, libgfor_cv_have_working_stat=no, [
 222 case "${target}" in
 223   *mingw*) libgfor_cv_have_working_stat=no ;;
 224   *) libgfor_cv_have_working_stat=yes;;
 225 esac])])
 226 if test x"$libgfor_cv_have_working_stat" = xyes; then
 227   AC_DEFINE(HAVE_WORKING_STAT, 1, [Define if target has a reliable stat.])
 228 fi])
 229
 230 dnl Checks for fpsetmask function.
 231 AC_DEFUN([LIBGFOR_CHECK_FPSETMASK], [
 232   AC_CACHE_CHECK([whether fpsetmask is present], libgfor_cv_have_fpsetmask, [
 233     AC_LINK_IFELSE([AC_LANG_PROGRAM([[
 234 #if HAVE_FLOATINGPOINT_H
 235 # include <floatingpoint.h>
 236 #endif /* HAVE_FLOATINGPOINT_H */
 237 #if HAVE_IEEEFP_H
 238 # include <ieeefp.h>
 239 #endif /* HAVE_IEEEFP_H */]],[[fpsetmask(0);]])],
 240     eval "libgfor_cv_have_fpsetmask=yes", eval "libgfor_cv_have_fpsetmask=no")
 241   ])
 242   if test x"$libgfor_cv_have_fpsetmask" = xyes; then
 243     have_fpsetmask=yes
 244     AC_DEFINE(HAVE_FPSETMASK, 1, [Define if you have fpsetmask.])
 245   fi
 246 ])
 247
 248 dnl Check whether we have a mingw that provides a __mingw_snprintf function
 249 AC_DEFUN([LIBGFOR_CHECK_MINGW_SNPRINTF], [
 250   AC_CACHE_CHECK([whether __mingw_snprintf is present], libgfor_cv_have_mingw_snprintf, [
 251     AC_LINK_IFELSE([AC_LANG_PROGRAM([[
 252 #include <stdio.h>
 253 extern int __mingw_snprintf (char *, size_t, const char *, ...);
 254 ]],[[
 255 __mingw_snprintf (NULL, 0, "%d\n", 1);
 256 ]])],
 257     eval "libgfor_cv_have_mingw_snprintf=yes", eval "libgfor_cv_have_mingw_snprintf=no")
 258   ])
 259   if test x"$libgfor_cv_have_mingw_snprintf" = xyes; then
 260     AC_DEFINE(HAVE_MINGW_SNPRINTF, 1, [Define if you have __mingw_snprintf.])
 261   fi
 262 ])
 263
 264 dnl Check whether we have a __float128 type
 265 AC_DEFUN([LIBGFOR_CHECK_FLOAT128], [
 266   LIBQUADSPEC=
 267
 268   if test "x$enable_libquadmath_support" != xno; then
 269
 270   AC_CACHE_CHECK([whether we have a usable __float128 type],
 271                  libgfor_cv_have_float128, [
 272    GCC_TRY_COMPILE_OR_LINK([
 273     typedef _Complex float __attribute__((mode(TC))) __complex128;
 274
 275     __float128 foo (__float128 x)
 276     {
 277
 278      __complex128 z1, z2;
 279
 280      z1 = x;
 281      z2 = x / 7.Q;
 282      z2 /= z1;
 283
 284      return (__float128) z2;
 285     }
 286
 287     __float128 bar (__float128 x)
 288     {
 289       return x * __builtin_huge_valq ();
 290     }
 291   ],[
 292     foo (1.2Q);
 293     bar (1.2Q);
 294   ],[
 295     libgfor_cv_have_float128=yes
 296   ],[
 297     libgfor_cv_have_float128=no
 298 ])])
 299
 300   if test "x$libgfor_cv_have_float128" = xyes; then
 301     AC_DEFINE(HAVE_FLOAT128, 1, [Define if have a usable __float128 type.])
 302
 303     dnl Check whether -Wl,--as-needed resp. -Wl,-zignore is supported
 304     dnl
 305     dnl Turn warnings into error to avoid testsuite breakage.  So enable
 306     dnl AC_LANG_WERROR, but there's currently (autoconf 2.64) no way to turn
 307     dnl it off again.  As a workaround, save and restore werror flag like
 308     dnl AC_PATH_XTRA.
 309     dnl Cf. http://gcc.gnu.org/ml/gcc-patches/2010-05/msg01889.html
 310     ac_xsave_[]_AC_LANG_ABBREV[]_werror_flag=$ac_[]_AC_LANG_ABBREV[]_werror_flag
 311     AC_CACHE_CHECK([whether --as-needed/-z ignore works],
 312       [libgfor_cv_have_as_needed],
 313       [
 314       # Test for native Solaris options first.
 315       # No whitespace after -z to pass it through -Wl.
 316       libgfor_cv_as_needed_option="-zignore"
 317       libgfor_cv_no_as_needed_option="-zrecord"
 318       save_LDFLAGS="$LDFLAGS"
 319       LDFLAGS="$LDFLAGS -Wl,$libgfor_cv_as_needed_option -lm -Wl,$libgfor_cv_no_as_needed_option"
 320       libgfor_cv_have_as_needed=no
 321       AC_LANG_WERROR
 322       AC_LINK_IFELSE([AC_LANG_PROGRAM([])],
 323                      [libgfor_cv_have_as_needed=yes],
 324                      [libgfor_cv_have_as_needed=no])
 325       LDFLAGS="$save_LDFLAGS"
 326       if test "x$libgfor_cv_have_as_needed" = xno; then
 327         libgfor_cv_as_needed_option="--as-needed"
 328         libgfor_cv_no_as_needed_option="--no-as-needed"
 329         save_LDFLAGS="$LDFLAGS"
 330         LDFLAGS="$LDFLAGS -Wl,$libgfor_cv_as_needed_option -lm -Wl,$libgfor_cv_no_as_needed_option"
 331         libgfor_cv_have_as_needed=no
 332         AC_LANG_WERROR
 333         AC_LINK_IFELSE([AC_LANG_PROGRAM([])],
 334                        [libgfor_cv_have_as_needed=yes],
 335                        [libgfor_cv_have_as_needed=no])
 336         LDFLAGS="$save_LDFLAGS"
 337       fi
 338       ac_[]_AC_LANG_ABBREV[]_werror_flag=$ac_xsave_[]_AC_LANG_ABBREV[]_werror_flag
 339     ])
 340
 341     dnl For static libgfortran linkage, depend on libquadmath only if needed.
 342     if test "x$libgfor_cv_have_as_needed" = xyes; then
 343       LIBQUADSPEC="%{static-libgfortran:$libgfor_cv_as_needed_option} -lquadmath %{static-libgfortran:$libgfor_cv_no_as_needed_option}"
 344     else
 345       LIBQUADSPEC="-lquadmath"
 346     fi
 347     if test -f ../libquadmath/libquadmath.la; then
 348       LIBQUADLIB=../libquadmath/libquadmath.la
 349       LIBQUADLIB_DEP=../libquadmath/libquadmath.la
 350       LIBQUADINCLUDE='-I$(srcdir)/../libquadmath'
 351     else
 352       LIBQUADLIB="-lquadmath"
 353       LIBQUADLIB_DEP=
 354       LIBQUADINCLUDE=
 355     fi
 356   fi
 357   else
 358     # for --disable-quadmath
 359     LIBQUADLIB=
 360     LIBQUADLIB_DEP=
 361     LIBQUADINCLUDE=
 362   fi
 363
 364   dnl For the spec file
 365   AC_SUBST(LIBQUADSPEC)
 366   AC_SUBST(LIBQUADLIB)
 367   AC_SUBST(LIBQUADLIB_DEP)
 368   AC_SUBST(LIBQUADINCLUDE)
 369
 370   dnl We need a conditional for the Makefile
 371   AM_CONDITIONAL(LIBGFOR_BUILD_QUAD, [test "x$libgfor_cv_have_float128" = xyes])
 372 ])
 373
 374
 375 dnl Check whether we have strerror_r
 376 AC_DEFUN([LIBGFOR_CHECK_STRERROR_R], [
 377   dnl Check for three-argument POSIX version of strerror_r
 378   ac_save_CFLAGS="$CFLAGS"
 379   CFLAGS="-Wimplicit-function-declaration -Werror"
 380   AC_TRY_COMPILE([#define _GNU_SOURCE 1
 381                   #include <string.h>
 382                   #include <locale.h>],
 383                   [char s[128]; strerror_r(5, s, 128);],
 384                   AC_DEFINE(HAVE_STRERROR_R, 1,
 385                   [Define if strerror_r is available in <string.h>.]),)
 386   CFLAGS="$ac_save_CFLAGS"
 387
 388   dnl Check for two-argument version of strerror_r (e.g. for VxWorks)
 389   ac_save_CFLAGS="$CFLAGS"
 390   CFLAGS="-Wimplicit-function-declaration -Werror"
 391   AC_TRY_COMPILE([#define _GNU_SOURCE 1
 392                   #include <string.h>
 393                   #include <locale.h>],
 394                   [char s[128]; strerror_r(5, s);],
 395                   AC_DEFINE(HAVE_STRERROR_R_2ARGS, 1,
 396                   [Define if strerror_r takes two arguments and is available in <string.h>.]),)
 397   CFLAGS="$ac_save_CFLAGS"
 398 ])
 399
 400 dnl Check for AVX
 401
 402 AC_DEFUN([LIBGFOR_CHECK_AVX], [
 403   ac_save_CFLAGS="$CFLAGS"
 404   CFLAGS="-O2 -mavx"
 405   AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
 406   void _mm256_zeroall (void)
 407         {
 408            __builtin_ia32_vzeroall ();
 409         }]], [[]])],
 410         AC_DEFINE(HAVE_AVX, 1,
 411         [Define if AVX instructions can be compiled.]),
 412         [])
 413   CFLAGS="$ac_save_CFLAGS"
 414 ])
 415
 416 dnl Check for AVX2
 417
 418 AC_DEFUN([LIBGFOR_CHECK_AVX2], [
 419   ac_save_CFLAGS="$CFLAGS"
 420   CFLAGS="-O2 -mavx2"
 421   AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
 422   typedef long long __v4di __attribute__ ((__vector_size__ (32)));
 423         __v4di
 424         mm256_is32_andnotsi256  (__v4di __X, __v4di __Y)
 425         {
 426            return __builtin_ia32_andnotsi256 (__X, __Y);
 427         }]], [[]])],
 428         AC_DEFINE(HAVE_AVX2, 1,
 429         [Define if AVX2 instructions can be compiled.]),
 430         [])
 431   CFLAGS="$ac_save_CFLAGS"
 432 ])
 433
 434 dnl Check for AVX512f
 435
 436 AC_DEFUN([LIBGFOR_CHECK_AVX512F], [
 437   ac_save_CFLAGS="$CFLAGS"
 438   CFLAGS="-O2 -mavx512f"
 439   AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
 440         typedef double __m512d __attribute__ ((__vector_size__ (64)));
 441         __m512d _mm512_add (__m512d a)
 442         {
 443           __m512d b = __builtin_ia32_addpd512_mask (a, a, a, 1, 4);
 444           /* For -m64/-mx32 also verify that code will work even if
 445              the target uses call saved zmm16+ and needs to emit
 446              unwind info for them (e.g. on mingw).  See PR79127.  */
 447 #ifdef __x86_64__
 448           asm volatile ("" : : : "zmm16", "zmm17", "zmm18", "zmm19");
 449 #endif
 450           return b;
 451         }]], [[]])],
 452         AC_DEFINE(HAVE_AVX512F, 1,
 453         [Define if AVX512f instructions can be compiled.]),
 454         [])
 455   CFLAGS="$ac_save_CFLAGS"
 456 ])
 457
 458 dnl Check for FMA3
 459 dnl
 460 AC_DEFUN([LIBGFOR_CHECK_FMA3], [
 461   ac_save_CFLAGS="$CFLAGS"
 462   CFLAGS="-O2 -mfma -mno-fma4"
 463   AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
 464         typedef float __m128 __attribute__ ((__vector_size__ (16)));
 465         typedef float __v4sf __attribute__ ((__vector_size__ (16)));
 466         __m128 _mm_macc_ps(__m128 __A, __m128 __B, __m128 __C)
 467         {
 468             return (__m128) __builtin_ia32_vfmaddps ((__v4sf)__A,
 469                                                      (__v4sf)__B,
 470                                                      (__v4sf)__C);
 471         }]], [[]])],
 472         AC_DEFINE(HAVE_FMA3, 1,
 473         [Define if FMA3 instructions can be compiled.]),
 474         [])
 475   CFLAGS="$ac_save_CFLAGS"
 476 ])
 477
 478 dnl Check for FMA4
 479 dnl
 480 AC_DEFUN([LIBGFOR_CHECK_FMA4], [
 481   ac_save_CFLAGS="$CFLAGS"
 482   CFLAGS="-O2 -mfma4 -mno-fma"
 483   AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
 484         typedef float __m128 __attribute__ ((__vector_size__ (16)));
 485         typedef float __v4sf __attribute__ ((__vector_size__ (16)));
 486         __m128 _mm_macc_ps(__m128 __A, __m128 __B, __m128 __C)
 487         {
 488             return (__m128) __builtin_ia32_vfmaddps ((__v4sf)__A,
 489                                                      (__v4sf)__B,
 490                                                      (__v4sf)__C);
 491         }]], [[]])],
 492         AC_DEFINE(HAVE_FMA4, 1,
 493         [Define if FMA4 instructions can be compiled.]),
 494         [])
 495   CFLAGS="$ac_save_CFLAGS"
 496 ])
 497
 498 dnl Check for -mprefer-avx128
 499 dnl This also defines an automake conditional.
 500 AC_DEFUN([LIBGFOR_CHECK_AVX128], [
 501   ac_save_CFLAGS="$CFLAGS"
 502   CFLAGS="-O2 -mavx -mprefer-avx128"
 503   AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
 504         void foo()
 505         {
 506         }]], [[]])],
 507         AC_DEFINE(HAVE_AVX128, 1,
 508         [Define if -mprefer-avx128 is supported.])
 509         AM_CONDITIONAL([HAVE_AVX128],true),
 510         [AM_CONDITIONAL([HAVE_AVX128],false)])
 511   CFLAGS="$ac_save_CFLAGS"
 512 ])