configure.ac

dnl Process this file with autoconf to produce a configure script.

dnl Define the fftw version number as M4 macros, so that we can enforce
dnl the invariant that the minor version number in FFTW-X.Y.MINOR is the same
dnl as the revision number in SHARED_VERSION_INFO.
define(FFTW_MAJOR_VERSION, 3.3)dnl
define(FFTW_MINOR_VERSION, 4)dnl

dnl Version number of the FFTW source package.
AC_INIT(fftw, FFTW_MAJOR_VERSION.FFTW_MINOR_VERSION, fftw@fftw.org)
AC_CONFIG_SRCDIR(kernel/ifftw.h)

dnl Version number for libtool shared libraries.  Libtool wants a string
dnl of the form CURRENT:REVISION:AGE.  We adopt the convention that
dnl REVISION is the same as the FFTW minor version number.
dnl fftw-3.1.x was 4:x:1
dnl fftw-3.2.x was 5:x:2
dnl fftw-3.3.x was 6:x:3 for x < 4 and 7:x:4 for x >= 4
SHARED_VERSION_INFO="7:FFTW_MINOR_VERSION:4" # CURRENT:REVISION:AGE

AM_INIT_AUTOMAKE(1.7)
AM_CONFIG_HEADER(config.h)
AC_CONFIG_MACRO_DIR([m4])
AM_MAINTAINER_MODE
AC_SUBST(SHARED_VERSION_INFO)
AC_DISABLE_SHARED dnl to hell with shared libraries
AC_CANONICAL_HOST

dnl configure options
case "${host_cpu}" in
  powerpc*) have_fma=yes;;
  ia64*) have_fma=yes;;
  hppa*) have_fma=yes;;
  mips64*) have_fma=yes;;
  *) have_fma=no;;
esac

AC_ARG_ENABLE(fma, [AC_HELP_STRING([--enable-fma],[enable optimizations for machines with fused multiply-add])], have_fma=$enableval)
if test "$have_fma"x = "yes"x; then
	AC_DEFINE(HAVE_FMA,1,[Define if you have a machine with fused multiply-add])
fi


AC_ARG_ENABLE(debug, [AC_HELP_STRING([--enable-debug],[compile fftw with extra runtime checks for debugging])], ok=$enableval, ok=no)
if test "$ok" = "yes"; then
	AC_DEFINE(FFTW_DEBUG,1,[Define to enable extra FFTW debugging code.])
	debug_malloc=yes
else
	debug_malloc=no
fi

AC_ARG_ENABLE(debug-malloc, [AC_HELP_STRING([--enable-debug-malloc],[enable malloc debugging version])], ok=$enableval, ok=$debug_malloc)
if test "$ok" = "yes"; then
	AC_DEFINE(FFTW_DEBUG_MALLOC,1,[Define to enable debugging malloc.])
fi

AC_ARG_ENABLE(debug-alignment, [AC_HELP_STRING([--enable-debug-alignment],[enable alignment debugging hacks])], ok=$enableval, ok=no)
if test "$ok" = "yes"; then
	AC_DEFINE(FFTW_DEBUG_ALIGNMENT,1,[Define to enable alignment debugging hacks.])
fi

AC_ARG_ENABLE(random-estimator, [AC_HELP_STRING([--enable-random-estimator],[enable pseudorandom estimator (debugging hack)])], ok=$enableval, ok=no)
if test "$ok" = "yes"; then
	AC_DEFINE(FFTW_RANDOM_ESTIMATOR,1,[Define to enable pseudorandom estimate planning for debugging.])
	CHECK_PL_OPTS="--estimate"
fi

AC_ARG_ENABLE(alloca, [AC_HELP_STRING([--disable-alloca],[disable use of the alloca() function (may be broken on mingw64)])], ok=$enableval, ok=yes)
if test "$ok" = "yes"; then
	AC_DEFINE(FFTW_ENABLE_ALLOCA,1,[Define to enable the use of alloca().])
fi

AC_ARG_ENABLE(single, [AC_HELP_STRING([--enable-single],[compile fftw in single precision])], ok=$enableval, ok=no)
AC_ARG_ENABLE(float, [AC_HELP_STRING([--enable-float],[synonym for --enable-single])], ok=$enableval)
if test "$ok" = "yes"; then
	AC_DEFINE(FFTW_SINGLE,1,[Define to compile in single precision.])
	AC_DEFINE(BENCHFFT_SINGLE,1,[Define to compile in single precision.])
	PRECISION=s
else
	PRECISION=d
fi
AM_CONDITIONAL(SINGLE, test "$ok" = "yes")

AC_ARG_ENABLE(long-double, [AC_HELP_STRING([--enable-long-double],[compile fftw in long-double precision])], ok=$enableval, ok=no)
if test "$ok" = "yes"; then
	if test "$PRECISION" = "s"; then
		AC_MSG_ERROR([--enable-single/--enable-long-double conflict])
	fi
	AC_DEFINE(FFTW_LDOUBLE,1,[Define to compile in long-double precision.])
	AC_DEFINE(BENCHFFT_LDOUBLE,1,[Define to compile in long-double precision.])
	PRECISION=l
fi
AM_CONDITIONAL(LDOUBLE, test "$ok" = "yes")

AC_ARG_ENABLE(quad-precision, [AC_HELP_STRING([--enable-quad-precision],[compile fftw in quadruple precision if available])], ok=$enableval, ok=no)
if test "$ok" = "yes"; then
	if test "$PRECISION" != "d"; then
		AC_MSG_ERROR([conflicting precisions specified])
	fi
	AC_DEFINE(FFTW_QUAD,1,[Define to compile in quad precision.])
	AC_DEFINE(BENCHFFT_QUAD,1,[Define to compile in quad precision.])
	PRECISION=q
fi
AM_CONDITIONAL(QUAD, test "$ok" = "yes")

AC_SUBST(PRECISION)
AC_SUBST(CHECK_PL_OPTS)

AC_ARG_ENABLE(sse, [AC_HELP_STRING([--enable-sse],[enable SSE optimizations])], have_sse=$enableval, have_sse=no)
if test "$have_sse" = "yes"; then
	if test "$PRECISION" != "s"; then
		AC_MSG_ERROR([SSE requires single precision])
	fi
fi

AC_ARG_ENABLE(sse2, [AC_HELP_STRING([--enable-sse2],[enable SSE/SSE2 optimizations])], have_sse2=$enableval, have_sse2=no)
if test "$have_sse" = "yes"; then have_sse2=yes; fi
if test "$have_sse2" = "yes"; then
	AC_DEFINE(HAVE_SSE2,1,[Define to enable SSE/SSE2 optimizations.])
	if test "$PRECISION" != "d" -a "$PRECISION" != "s"; then
		AC_MSG_ERROR([SSE2 requires single or double precision])
	fi
fi
AM_CONDITIONAL(HAVE_SSE2, test "$have_sse2" = "yes")

AC_ARG_ENABLE(avx, [AC_HELP_STRING([--enable-avx],[enable AVX optimizations])], have_avx=$enableval, have_avx=no)
if test "$have_avx" = "yes"; then
        AC_DEFINE(HAVE_AVX,1,[Define to enable AVX optimizations.])
	if test "$PRECISION" != "d" -a "$PRECISION" != "s"; then
		AC_MSG_ERROR([AVX requires single or double precision])
	fi
fi
AM_CONDITIONAL(HAVE_AVX, test "$have_avx" = "yes")

AC_ARG_ENABLE(avx2, [AC_HELP_STRING([--enable-avx2],[enable AVX2 optimizations])], have_avx2=$enableval, have_avx2=no)
if test "$have_avx2" = "yes"; then
        AC_DEFINE(HAVE_AVX2,1,[Define to enable AVX2 optimizations.])
	if test "$PRECISION" != "d" -a "$PRECISION" != "s"; then
		AC_MSG_ERROR([AVX2 requires single or double precision])
	fi
fi
AM_CONDITIONAL(HAVE_AVX2, test "$have_avx2" = "yes")

AC_ARG_ENABLE(avx512, [AC_HELP_STRING([--enable-avx512],[enable AVX512 optimizations])], have_avx512=$enableval, have_avx512=no)
if test "$have_avx512" = "yes"; then
        AC_DEFINE(HAVE_AVX512,1,[Define to enable AVX512 optimizations.])
	if test "$PRECISION" != "d" -a "$PRECISION" != "s"; then
		AC_MSG_ERROR([AVX512 requires single or double precision])
	fi
fi
AM_CONDITIONAL(HAVE_AVX512, test "$have_avx512" = "yes")

AC_ARG_ENABLE(kcvi, [AC_HELP_STRING([--enable-kcvi],[enable Knights Corner vector instructions optimizations])], have_kcvi=$enableval, have_kcvi=no)
if test "$have_kcvi" = "yes"; then
        AC_DEFINE(HAVE_KCVI,1,[Define to enable KCVI optimizations.])
	if test "$PRECISION" != "d" -a "$PRECISION" != "s"; then
		AC_MSG_ERROR([Knights Corner vector instructions requires single or double precision])
	fi
fi
AM_CONDITIONAL(HAVE_KCVI, test "$have_kcvi" = "yes")

AC_ARG_ENABLE(altivec, [AC_HELP_STRING([--enable-altivec],[enable Altivec optimizations])], have_altivec=$enableval, have_altivec=no)
if test "$have_altivec" = "yes"; then
	AC_DEFINE(HAVE_ALTIVEC,1,[Define to enable Altivec optimizations.])
	if test "$PRECISION" != "s"; then
		AC_MSG_ERROR([Altivec requires single precision])
	fi
fi
AM_CONDITIONAL(HAVE_ALTIVEC, test "$have_altivec" = "yes")

AC_ARG_ENABLE(vsx, [AC_HELP_STRING([--enable-vsx],[enable IBM VSX optimizations])], have_vsx=$enableval, have_vsx=no)
if test "$have_vsx" = "yes"; then
        AC_DEFINE(HAVE_VSX,1,[Define to enable IBM VSX optimizations.])
fi
AM_CONDITIONAL(HAVE_VSX, test "$have_vsx" = "yes")

AC_ARG_ENABLE(neon, [AC_HELP_STRING([--enable-neon],[enable ARM NEON optimizations])], have_neon=$enableval, have_neon=no)
if test "$have_neon" = "yes"; then
	AC_DEFINE(HAVE_NEON,1,[Define to enable ARM NEON optimizations.])
        case "${host_cpu}" in
                aarch64)
                ;;
                *)
		if test "$PRECISION" != "s"; then
			AC_MSG_ERROR([NEON requires single precision])
		fi
                ;;
        esac
fi
AM_CONDITIONAL(HAVE_NEON, test "$have_neon" = "yes")

AC_ARG_ENABLE(armv8cyclecounter, [AC_HELP_STRING([--enable-armv8cyclecounter],[enable the cycle counter on ARMv8 ; require enabling in kernel mode, see <https://github.com/rdolbeau/enable_arm_pmu>])], have_armv8cyclecounter=$enableval)
if test "$have_armv8cyclecounter"x = "yes"x; then
	AC_DEFINE(HAVE_ARMV8CC,1,[Define if you have enabled the cycle counter on ARMv8])
fi

AC_ARG_ENABLE(generic-simd128, [AC_HELP_STRING([--enable-generic-simd128],[enable generic (gcc) 128-bit SIMD optimizations])], have_generic_simd128=$enableval, have_generic_simd128=no)
if test "$have_generic_simd128" = "yes"; then
        AC_DEFINE(HAVE_GENERIC_SIMD128,1,[Define to enable generic (gcc) 128-bit SIMD optimizations.])
fi
AM_CONDITIONAL(HAVE_GENERIC_SIMD128, test "$have_generic_simd" = "yes")

AC_ARG_ENABLE(generic-simd256, [AC_HELP_STRING([--enable-generic-simd256],[enable generic (gcc) 256-bit SIMD optimizations])], have_generic_simd256=$enableval, have_generic_simd256=no)
if test "$have_generic_simd256" = "yes"; then
        AC_DEFINE(HAVE_GENERIC_SIMD256,1,[Define to enable generic (gcc) 256-bit SIMD optimizations.])
fi
AM_CONDITIONAL(HAVE_GENERIC_SIMD256, test "$have_generic_simd256" = "yes")


dnl FIXME:
dnl AC_ARG_ENABLE(mips-ps, [AC_HELP_STRING([--enable-mips-ps],[enable MIPS pair-single optimizations])], have_mips_ps=$enableval, have_mips_ps=no)
dnl if test "$have_mips_ps" = "yes"; then
dnl 	AC_DEFINE(HAVE_MIPS_PS,1,[Define to enable MIPS paired-single optimizations.])
dnl 	if test "$PRECISION" != "s"; then
dnl 		AC_MSG_ERROR([MIPS paired-single requires single precision])
dnl 	fi
dnl fi
dnl AM_CONDITIONAL(HAVE_MIPS_PS, test "$have_mips_ps" = "yes")

AC_ARG_WITH(slow-timer, [AC_HELP_STRING([--with-slow-timer],[use low-precision timers (SLOW)])], with_slow_timer=$withval, with_slow_timer=no)
if test "$with_slow_timer" = "yes"; then
	AC_DEFINE(WITH_SLOW_TIMER,1,[Use low-precision timers, making planner very slow])
fi

AC_ARG_ENABLE(mips_zbus_timer, [AC_HELP_STRING([--enable-mips-zbus-timer],[use MIPS ZBus cycle-counter])], have_mips_zbus_timer=$enableval, have_mips_zbus_timer=no)
if test "$have_mips_zbus_timer" = "yes"; then
	AC_DEFINE(HAVE_MIPS_ZBUS_TIMER,1,[Define to enable use of MIPS ZBus cycle-counter.])
fi

AC_ARG_WITH(our-malloc, [AC_HELP_STRING([--with-our-malloc],[use our aligned malloc (helpful for Win32)])], with_our_malloc=$withval, with_our_malloc=no)
AC_ARG_WITH(our-malloc16, [AC_HELP_STRING([--with-our-malloc16],[Obsolete alias for --with-our-malloc16])], with_our_malloc=$withval)
if test "$with_our_malloc" = "yes"; then
	AC_DEFINE(WITH_OUR_MALLOC,1,[Use our own aligned malloc routine; mainly helpful for Windows systems lacking aligned allocation system-library routines.])
fi

AC_ARG_WITH(windows-f77-mangling, [AC_HELP_STRING([--with-windows-f77-mangling],[use common Win32 Fortran interface styles])], with_windows_f77_mangling=$withval, with_windows_f77_mangling=no)
if test "$with_windows_f77_mangling" = "yes"; then
	AC_DEFINE(WINDOWS_F77_MANGLING,1,[Use common Windows Fortran mangling styles for the Fortran interfaces.])
fi

AC_ARG_WITH(incoming-stack-boundary, [AC_HELP_STRING([--with-incoming-stack-boundary=X],[Assume that stack is aligned to (1<<X) bytes])], with_incoming_stack_boundary=$withval, with_incoming_stack_boundary=no)

dnl compute library suffix
case "$PRECISION" in
     s) PREC_SUFFIX=f;;
     d) PREC_SUFFIX=;;
     l) PREC_SUFFIX=l;;
     q) PREC_SUFFIX=q;;
esac
AC_SUBST(PREC_SUFFIX)

dnl Checks for programs.
AC_PROG_CC
AM_PROG_CC_C_O
AX_COMPILER_VENDOR
AC_PROG_CC_STDC
AC_PROG_INSTALL
AC_PROG_LN_S
AC_PROG_MAKE_SET
AC_LIBTOOL_WIN32_DLL
AC_PROG_LIBTOOL

AC_CHECK_PROG(OCAMLBUILD, ocamlbuild, ocamlbuild)

dnl -----------------------------------------------------------------------

AC_ARG_ENABLE(mpi, [AC_HELP_STRING([--enable-mpi],[compile FFTW MPI library])], enable_mpi=$enableval, enable_mpi=no)

if test "$enable_mpi" = "yes"; then
   if test $PRECISION = q; then
      AC_MSG_ERROR([quad precision is not supported in MPI])
   fi
   ACX_MPI([],[AC_MSG_ERROR([could not find mpi library for --enable-mpi])])
   AC_CHECK_PROG(MPIRUN, mpirun, mpirun)
   AC_SUBST(MPIRUN)

   save_CC=$CC
   CC=$MPICC
   AC_CHECK_SIZEOF(MPI_Fint, [], [#include <mpi.h>])
   CC=$save_CC
   if test 0 = $ac_cv_sizeof_MPI_Fint; then
      AC_MSG_WARN([sizeof(MPI_Fint) test failed]);
      dnl As a backup, assume Fortran integer == C int
      AC_CHECK_SIZEOF(int) 
      if test 0 = $ac_cv_sizeof_int; then AC_MSG_ERROR([sizeof(int) test failed]); fi
      ac_cv_sizeof_MPI_Fint=$ac_cv_sizeof_int
   fi
   C_MPI_FINT=C_INT`expr $ac_cv_sizeof_MPI_Fint \* 8`_T
   AC_SUBST(C_MPI_FINT)
fi
AM_CONDITIONAL(MPI, test "$enable_mpi" = "yes")

dnl -----------------------------------------------------------------------

dnl determine CFLAGS first
AX_CC_MAXOPT

case "${ax_cv_c_compiler_vendor}" in
   intel) # Stop icc from defining __GNUC__, except on MacOS where this fails
        case "${host_os}" in
            *darwin*) ;; # icc -no-gcc fails to compile some system headers
            *) 
	       AX_CHECK_COMPILER_FLAGS([-no-gcc], [CC="$CC -no-gcc"])
               ;;
        esac
        ;;

   hp) # must (sometimes) manually increase cpp limits to handle fftw3.h
        AX_CHECK_COMPILER_FLAGS([-Wp,-H128000],
        		        [CC="$CC -Wp,-H128000"])
        ;;

   portland) # -Masmkeyword required for asm("") cycle counters
	AX_CHECK_COMPILER_FLAGS([-Masmkeyword],
                                [CC="$CC -Masmkeyword"])
        ;;
esac

dnl Determine SIMD CFLAGS at least for gcc and icc
case "${ax_cv_c_compiler_vendor}" in
    gnu|intel)
	# SSE/SSE2
	if test "$have_sse2" = "yes" -a "x$SSE2_CFLAGS" = x; then
	    if test "$PRECISION" = d; then flag=msse2; else flag=msse; fi
	    AX_CHECK_COMPILER_FLAGS(-$flag, [SSE2_CFLAGS="-$flag"],
		[AC_MSG_ERROR([Need a version of gcc with -$flag])])
	fi

	# AVX
	if test "$have_avx" = "yes" -a "x$AVX_CFLAGS" = x; then
	    AX_CHECK_COMPILER_FLAGS(-mavx, [AVX_CFLAGS="-mavx"],
		[AC_MSG_ERROR([Need a version of gcc with -mavx])])
	fi

        # AVX2
        # gcc-4.8 works with -march=core-avx2, but -mavx2 is not enough.
        # Later versions seem to happy with -mavx2, so try the arch one first.
        if test "$have_avx2" = "yes" -a "x$AVX2_CFLAGS" = x; then
            AX_CHECK_COMPILER_FLAGS(-march=core-avx2, [AVX2_CFLAGS="-march=core-avx2"],
                [AX_CHECK_COMPILER_FLAGS(-mavx2, [AVX2_CFLAGS="-mavx2"],
                    [AC_MSG_ERROR([Need a version of gcc with either -march=core-avx2 or -mavx2])])])
            AX_CHECK_COMPILER_FLAGS(-mfma, [AVX2_CFLAGS="$AVX2_CFLAGS -mfma"],
                [AC_MSG_WARN([Need a version of gcc with -mfma (harmless for icc)])])
        fi

	# AVX512
	if test "$have_avx512" = "yes" -a "x$AVX512_CFLAGS" = x; then
	    AX_CHECK_COMPILER_FLAGS(-mavx512f, [AVX512_CFLAGS="-mavx512f"],
		[AC_MSG_ERROR([Need a version of gcc with -mavx512f])])
	fi

	# KCVI
	if test "$have_kcvi" = "yes" -a "x$KCVI_CFLAGS" = x; then
	    AX_CHECK_COMPILER_FLAGS(-mmic, [KCVI_CFLAGS="-mmic"],
		[AC_MSG_ERROR([Need a version of icc with -mmic])])
	fi

	if test "$have_altivec" = "yes" -a "x$ALTIVEC_CFLAGS" = x; then
	    # -DFAKE__VEC__ is a workaround because gcc-3.3 does not
	    # #define __VEC__ with -maltivec.
	    AX_CHECK_COMPILER_FLAGS(-faltivec, [ALTIVEC_CFLAGS="-faltivec"],
		[AX_CHECK_COMPILER_FLAGS(-maltivec -mabi=altivec,
		    [ALTIVEC_CFLAGS="-maltivec -mabi=altivec -DFAKE__VEC__"],
		    [AX_CHECK_COMPILER_FLAGS(-fvec, [ALTIVEC_CFLAGS="-fvec"],
			[AC_MSG_ERROR([Need a version of gcc with -maltivec])])])])
	fi

        case "${host_cpu}" in
                aarch64)
                ;;
                *)
	        if test "$have_neon" = "yes" -a "x$NEON_CFLAGS" = x; then
	            AX_CHECK_COMPILER_FLAGS(-mfpu=neon, [NEON_CFLAGS="-mfpu=neon"],
			[AC_MSG_ERROR([Need a version of gcc with -mfpu=neon])])
	        fi
                ;;
        esac

        if test "$have_vsx" = "yes" -a "x$VSX_CFLAGS" = x; then
            AX_CHECK_COMPILER_FLAGS(-mvsx, [VSX_CFLAGS="-mvsx"],
                [AC_MSG_ERROR([Need a version of gcc with -mvsx])])
        fi

	dnl FIXME:
	dnl elif test "$have_mips_ps" = "yes"; then
	dnl     # Just punt here and use only new 4.2 compiler :(
	dnl 	# Should add section for older compilers...
	dnl 	AX_CHECK_COMPILER_FLAGS(-mpaired-single,
	dnl 	    [SIMD_CFLAGS="-mpaired-single"],
	dnl 	    #[AC_MSG_ERROR([Need a version of gcc with -mpaired-single])])
	dnl 	    [AX_CHECK_COMPILER_FLAGS(-march=mips64,
	dnl 	      [SIMD_CFLAGS="-march=mips64"],
	dnl 	        [AC_MSG_ERROR(
	dnl 		 [Need a version of gcc with -mpaired-single or -march=mips64])
	dnl 		])])
	dnl fi
	;;

    clang)
        if test "$have_vsx" = "yes" -a "x$VSX_CFLAGS" = x; then
            # clang appears to need both -mvsx and -maltivec for VSX
            AX_CHECK_COMPILER_FLAGS(-maltivec, [VSX_CFLAGS="-maltivec"],
                [AC_MSG_ERROR([Need a version of gcc with -maltivec])])
            AX_CHECK_COMPILER_FLAGS(-mvsx, [VSX_CFLAGS="-mvsx $VSX_CFLAGS"],
                [AC_MSG_ERROR([Need a version of gcc with -mvsx])])
        fi
        ;;

    ibm)
        if test "$have_vsx" = "yes" -a "x$VSX_CFLAGS" = x; then
            # Note that IBM xlC uses -qaltivec for VSX too.
            AX_CHECK_COMPILER_FLAGS(-qaltivec, [VSX_CFLAGS="-qaltivec"],
                [AC_MSG_ERROR([Need a version of gcc with -qaltivec])])
        fi
        ;;
esac

AC_SUBST(SSE2_CFLAGS)
AC_SUBST(AVX_CFLAGS)
AC_SUBST(AVX2_CFLAGS)
AC_SUBST(AVX512_CFLAGS)
AC_SUBST(KCVI_CFLAGS)
AC_SUBST(ALTIVEC_CFLAGS)
AC_SUBST(VSX_CFLAGS)
AC_SUBST(NEON_CFLAGS)

dnl add stack alignment CFLAGS if so requested
if test "$with_incoming_stack_boundary"x != "no"x; then
   case "${ax_cv_c_compiler_vendor}" in
      gnu)
        tentative_flags="-mincoming-stack-boundary=$with_incoming_stack_boundary";
        AX_CHECK_COMPILER_FLAGS($tentative_flags, 
	          [STACK_ALIGN_CFLAGS=$tentative_flags])
      ;;
   esac
fi
AC_SUBST(STACK_ALIGN_CFLAGS)

dnl Checks for header files.
AC_HEADER_STDC
AC_CHECK_HEADERS([libintl.h malloc.h stddef.h stdlib.h string.h strings.h sys/time.h unistd.h limits.h c_asm.h intrinsics.h stdint.h mach/mach_time.h sys/sysctl.h])
dnl c_asm.h: Header file for enabling asm() on Digital Unix  
dnl intrinsics.h: cray unicos
dnl sys/sysctl.h: MacOS X altivec detection

dnl altivec.h requires $ALTIVEC_CFLAGS (we use this for VSX too, which uses the same header)
save_CFLAGS="$CFLAGS"
save_CPPFLAGS="$CPPFLAGS"
CFLAGS="$CFLAGS $ALTIVEC_CFLAGS $VSX_CFLAGS"
CPPFLAGS="$CPPFLAGS $ALTIVEC_CFLAGS $VSX_CFLAGS"
AC_CHECK_HEADERS([altivec.h])
CFLAGS="$save_CFLAGS"
CPPFLAGS="$save_CPPFLAGS"


dnl Checks for typedefs, structures, and compiler characteristics.
AC_C_CONST
AC_C_INLINE
AC_TYPE_SIZE_T
AC_HEADER_TIME
AC_CHECK_TYPE([long double],
              [AC_DEFINE(HAVE_LONG_DOUBLE, 1, [Define to 1 if the compiler supports `long double'])],
[
if test $PRECISION = l; then
    AC_MSG_ERROR([long double is not a supported type with your compiler.])
fi
])
AC_CHECK_TYPE([hrtime_t],[AC_DEFINE(HAVE_HRTIME_T, 1, [Define to 1 if hrtime_t is defined in <sys/time.h>])],,
[
#if HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
])

AC_CHECK_SIZEOF(int)
AC_CHECK_SIZEOF(unsigned int)
AC_CHECK_SIZEOF(long)
AC_CHECK_SIZEOF(unsigned long)
AC_CHECK_SIZEOF(long long)
AC_CHECK_SIZEOF(unsigned long long)
AC_CHECK_SIZEOF(size_t)
AC_CHECK_SIZEOF(ptrdiff_t)

AC_CHECK_TYPES(uintptr_t, [], [AC_CHECK_SIZEOF(void *)], [$ac_includes_default
#ifdef HAVE_STDINT_H
#  include <stdint.h>
#endif])

AC_CHECK_SIZEOF(float)
AC_CHECK_SIZEOF(double)

dnl Check sizeof fftw_r2r_kind for Fortran interface [it has == sizeof(int)
dnl for years, but being paranoid].  Note: the definition here must match
dnl the one in api/fftw3.h!
AC_CHECK_SIZEOF(fftw_r2r_kind, [], [typedef enum {
     FFTW_R2HC=0, FFTW_HC2R=1, FFTW_DHT=2,
     FFTW_REDFT00=3, FFTW_REDFT01=4, FFTW_REDFT10=5, FFTW_REDFT11=6,
     FFTW_RODFT00=7, FFTW_RODFT01=8, FFTW_RODFT10=9, FFTW_RODFT11=10
} fftw_r2r_kind;])
if test 0 = $ac_cv_sizeof_fftw_r2r_kind; then AC_MSG_ERROR([sizeof(fftw_r2r_kind) test failed]); fi
C_FFTW_R2R_KIND=C_INT`expr $ac_cv_sizeof_fftw_r2r_kind \* 8`_T
AC_SUBST(C_FFTW_R2R_KIND)

dnl Checks for library functions.
AC_FUNC_ALLOCA
AC_FUNC_STRTOD
AC_FUNC_VPRINTF
AC_CHECK_LIB(m, sin)

if test $PRECISION = q; then
   AX_GCC_VERSION(4,6,0,[],[AC_MSG_ERROR([gcc 4.6 or later required for quad precision support])])
   AC_CHECK_LIB(quadmath, sinq, [], [AC_MSG_ERROR([quad precision requires libquadmath for quad-precision trigonometric routines])])
   LIBQUADMATH=-lquadmath
fi
AC_SUBST(LIBQUADMATH)

AC_CHECK_FUNCS([BSDgettimeofday gettimeofday gethrtime read_real_time time_base_to_time drand48 sqrt memset posix_memalign memalign _mm_malloc _mm_free clock_gettime mach_absolute_time sysctl abort sinl cosl snprintf])
AC_CHECK_DECLS([sinl, cosl, sinq, cosq],,,[#include <math.h>])
AC_CHECK_DECLS([memalign],,,[
#ifdef HAVE_MALLOC_H
#include <malloc.h>
#endif])
AC_CHECK_DECLS([drand48, srand48, posix_memalign]) dnl in stdlib.h

dnl Cray UNICOS _rtc() (real-time clock) intrinsic
AC_MSG_CHECKING([for _rtc intrinsic])
rtc_ok=yes
AC_TRY_LINK([#ifdef HAVE_INTRINSICS_H
#include <intrinsics.h>
#endif], [_rtc()], [AC_DEFINE(HAVE__RTC,1,[Define if you have the UNICOS _rtc() intrinsic.])], [rtc_ok=no])
AC_MSG_RESULT($rtc_ok)

if test "$PRECISION" = "l"; then
	AC_CHECK_FUNCS([cosl sinl tanl], [], [AC_MSG_ERROR([long-double precision requires long-double trigonometric routines])])
fi

AC_MSG_CHECKING([for isnan])
AC_TRY_LINK([#include <math.h>
], if (!isnan(3.14159)) isnan(2.7183);, ok=yes, ok=no)
if test "$ok" = "yes"; then
	AC_DEFINE(HAVE_ISNAN,1,[Define if the isnan() function/macro is available.])
fi
AC_MSG_RESULT(${ok})

dnl TODO
AX_GCC_ALIGNS_STACK()

dnl override CFLAGS selection when debugging
if test "${enable_debug}" = "yes"; then
	CFLAGS="-g"
fi

dnl add gcc warnings, in debug/maintainer mode only
if test "$enable_debug" = yes || test "$USE_MAINTAINER_MODE" = yes; then
if test "$ac_test_CFLAGS" != "set"; then
	if test $ac_cv_prog_gcc = yes; then
		CFLAGS="$CFLAGS -Wall -W -Wcast-qual -Wpointer-arith -Wcast-align -pedantic -Wno-long-long -Wshadow -Wbad-function-cast -Wwrite-strings -Wstrict-prototypes -Wredundant-decls -Wnested-externs" # -Wundef -Wconversion -Wmissing-prototypes -Wmissing-declarations 
	fi
fi
fi

dnl -----------------------------------------------------------------------

AC_ARG_ENABLE(fortran, [AC_HELP_STRING([--disable-fortran],[don't include Fortran-callable wrappers])], enable_fortran=$enableval, enable_fortran=yes)

if test "$enable_fortran" = "yes"; then
        AC_PROG_F77
        if test -z "$F77"; then
                enable_fortran=no
                AC_MSG_WARN([*** Couldn't find f77 compiler; using default Fortran wrappers.])
	else
		AC_F77_DUMMY_MAIN([], [enable_fortran=no
			AC_MSG_WARN([*** Couldn't figure out how to link C and Fortran; using default Fortran wrappers.])])
        fi
else
	AC_DEFINE([DISABLE_FORTRAN], 1, [Define to disable Fortran wrappers.])
fi

if test "x$enable_fortran" = xyes; then
        AC_F77_WRAPPERS
	AC_F77_FUNC(f77foo)
	AC_F77_FUNC(f77_foo)
	f77_foo2=`echo $f77foo | sed 's/77/77_/'`
	if test "$f77_foo" = "$f77_foo2"; then
		AC_DEFINE(F77_FUNC_EQUIV, 1, [Define if F77_FUNC and F77_FUNC_ are equivalent.])

		# Include g77 wrappers by default for GNU systems or gfortran
		with_g77_wrappers=$ac_cv_f77_compiler_gnu
		case $host_os in *gnu*) with_g77_wrappers=yes ;; esac
	fi
else
	with_g77_wrappers=no
fi

AC_ARG_WITH(g77-wrappers, [AC_HELP_STRING([--with-g77-wrappers],[force inclusion of g77-compatible wrappers in addition to any other Fortran compiler that is detected])], with_g77_wrappers=$withval)
if test "x$with_g77_wrappers" = "xyes"; then
	AC_DEFINE(WITH_G77_WRAPPERS,1,[Include g77-compatible wrappers in addition to any other Fortran wrappers.])
fi

dnl -----------------------------------------------------------------------
have_smp="no"
AC_ARG_ENABLE(openmp, [AC_HELP_STRING([--enable-openmp],[use OpenMP directives for parallelism])], enable_openmp=$enableval, enable_openmp=no)

if test "$enable_openmp" = "yes"; then
   AC_DEFINE(HAVE_OPENMP,1,[Define to enable OpenMP])
   AX_OPENMP([], [AC_MSG_ERROR([don't know how to enable OpenMP])])
fi

AC_ARG_ENABLE(threads, [AC_HELP_STRING([--enable-threads],[compile FFTW SMP threads library])], enable_threads=$enableval, enable_threads=no)

if test "$enable_threads" = "yes"; then
   AC_DEFINE(HAVE_THREADS,1,[Define to enable SMP threads])
fi

AC_ARG_WITH(combined-threads, [AC_HELP_STRING([--with-combined-threads],[combine threads into main libfftw3])], with_combined_threads=$withval, with_combined_threads=no)

if test "$with_combined_threads" = yes; then
   if test "$enable_openmp" = "yes"; then
      AC_MSG_ERROR([--with-combined-threads incompatible with --enable-openmp])
   fi
   if test "$enable_threads" != "yes"; then
      AC_MSG_ERROR([--with-combined-threads requires --enable-threads])
   fi
fi

dnl Check for threads library...
THREADLIBS=""
if test "$enable_threads" = "yes"; then
        # Win32 threads are the default on Windows:
	if test -z "$THREADLIBS"; then
		AC_MSG_CHECKING([for Win32 threads])
		AC_TRY_LINK([#include <windows.h>],
			[_beginthreadex(0,0,0,0,0,0);],
			[THREADLIBS=" "; AC_MSG_RESULT(yes)],
			[AC_MSG_RESULT(no)])
	fi

	# POSIX threads, the default choice everywhere else:
	if test -z "$THREADLIBS"; then
		ACX_PTHREAD([THREADLIBS="$PTHREAD_LIBS "
	                     CC="$PTHREAD_CC"
	                     AC_DEFINE(USING_POSIX_THREADS, 1, [Define if we have and are using POSIX threads.])])
	fi

	if test -z "$THREADLIBS"; then
		AC_MSG_ERROR([couldn't find threads library for --enable-threads])
	fi
	AC_DEFINE(HAVE_THREADS, 1, [Define if we have a threads library.])
fi
AC_SUBST(THREADLIBS)
AM_CONDITIONAL(THREADS, test "$enable_threads" = "yes")
AM_CONDITIONAL(OPENMP, test "$enable_openmp" = "yes")
AM_CONDITIONAL(SMP, test "$enable_threads" = "yes" -o "$enable_openmp" = "yes")
AM_CONDITIONAL(COMBINED_THREADS, test x"$with_combined_threads" = xyes)


dnl -----------------------------------------------------------------------
dnl Check for not-always-available (not quite) cycle counters
case "${host_cpu}" in
        armv7*)
        AC_MSG_CHECKING([armv7a has 64 bits readable CNTVCT])
        AC_RUN_IFELSE(
                [AC_LANG_PROGRAM([[#include <stdint.h>]],
                        [[uint32_t Rt, Rt2 = 0;asm volatile("mrrc p15, 1, %0, %1, c14" : "=r"(Rt), "=r"(Rt2));]]
                )],
                [AC_DEFINE(ARMV7A_HAS_CNTCVT,1,[Define if CNTVCT is 64 bits readable on armv7a ])
                 AC_MSG_RESULT([yes])],
                [AC_MSG_RESULT([no])]
                )
        ;;
        aarch64)
        AC_MSG_CHECKING([armv8 has 64 bits readable CNTVCT_EL0])
        AC_RUN_IFELSE(
                [AC_LANG_PROGRAM([[#include <stdint.h>]],
                        [[uint64_t Rt;asm volatile("mrs %0, CNTVCT_EL0" : "=r" (Rt));]]
                )],
                [AC_DEFINE(ARMV8_HAS_CNTCVT_EL0,1,[Define if CNTVCT_EL0 is 64 bits readable on armv8 ])
                 AC_MSG_RESULT([yes])],
                [AC_MSG_RESULT([no])]
                )
        ;;
        *)
        ;;
esac

dnl -----------------------------------------------------------------------

AC_MSG_CHECKING([whether a cycle counter is available])
save_CPPFLAGS=$CPPFLAGS
CPPFLAGS="$CPPFLAGS -I$srcdir/kernel"
AC_TRY_CPP([#include "cycle.h"
#ifndef HAVE_TICK_COUNTER
#  error No cycle counter
#endif], [ok=yes], [ok=no])
CPPFLAGS=$save_CPPFLAGS
AC_MSG_RESULT($ok)
if test $ok = no && test "x$with_slow_timer" = xno; then
	echo "***************************************************************"
	echo "WARNING: No cycle counter found.  FFTW will use ESTIMATE mode  "
	echo "         for all plans.  See the manual for more information."
	echo "***************************************************************"
fi

dnl -----------------------------------------------------------------------

AC_DEFINE_UNQUOTED(FFTW_CC, "$CC $CFLAGS", [C compiler name and flags])

AC_CONFIG_FILES([
   Makefile
   support/Makefile
   genfft/Makefile
   kernel/Makefile
   simd-support/Makefile

   dft/Makefile
   dft/scalar/Makefile
   dft/scalar/codelets/Makefile
   dft/simd/Makefile
   dft/simd/common/Makefile
   dft/simd/sse2/Makefile
   dft/simd/avx/Makefile
   dft/simd/avx-128/Makefile
   dft/simd/avx2/Makefile
   dft/simd/avx2-128/Makefile
   dft/simd/avx512/Makefile
   dft/simd/kcvi/Makefile
   dft/simd/altivec/Makefile
   dft/simd/vsx/Makefile
   dft/simd/neon/Makefile
   dft/simd/generic-simd128/Makefile
   dft/simd/generic-simd256/Makefile

   rdft/Makefile
   rdft/scalar/Makefile
   rdft/scalar/r2cf/Makefile
   rdft/scalar/r2cb/Makefile
   rdft/scalar/r2r/Makefile
   rdft/simd/Makefile
   rdft/simd/common/Makefile
   rdft/simd/sse2/Makefile
   rdft/simd/avx/Makefile
   rdft/simd/avx-128/Makefile
   rdft/simd/avx2/Makefile
   rdft/simd/avx2-128/Makefile
   rdft/simd/avx512/Makefile
   rdft/simd/kcvi/Makefile
   rdft/simd/altivec/Makefile
   rdft/simd/vsx/Makefile
   rdft/simd/neon/Makefile
   rdft/simd/generic-simd128/Makefile
   rdft/simd/generic-simd256/Makefile

   reodft/Makefile

   threads/Makefile

   api/Makefile

   mpi/Makefile

   libbench2/Makefile
   tests/Makefile
   doc/Makefile
   doc/FAQ/Makefile

   tools/Makefile
   tools/fftw_wisdom.1
   tools/fftw-wisdom-to-conf

   m4/Makefile

   fftw.pc
])

AC_OUTPUT