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|
# AC_C_OPENMP
# -----------
# Check which options need to be passed to the C compiler to support OpenMP.
# Set the OPENMP_CFLAGS variable to these options.
# The options are necessary at compile time (so the #pragmas are understood)
# and at link time (so the appropriate library is linked with).
# This macro takes care to not produce redundant options if $CC $CFLAGS already
# supports OpenMP. It also is careful to not pass options to compilers that
# misinterpret them; for example, most compilers accept "-openmp" and create
# an output file called 'penmp' rather than activating OpenMP support.
AC_DEFUN([AC_C_OPENMP],
[
AC_MSG_CHECKING([whether to use OpenMP])
AC_ARG_ENABLE(openmp,
[AS_HELP_STRING([--enable-openmp], [use OpenMP if available])],
[enable_openmp=$enableval]
)
AC_MSG_RESULT([$enable_openmp])
ac_openmp_result=no
OPENMP_CFLAGS=
if test "$enable_openmp" = yes; then
AC_MSG_CHECKING([for $CC option to support OpenMP])
AC_CACHE_VAL([ac_cv_prog_cc_openmp], [
ac_cv_prog_cc_openmp=unsupported
AC_LINK_IFELSE([
#ifndef _OPENMP
choke me
#endif
#include <omp.h>
int main () { return omp_get_num_threads (); }
], [ac_cv_prog_cc_openmp="none needed"])
if test "$ac_cv_prog_cc_openmp" = unsupported; then
dnl Try these flags:
dnl GCC >= 4.2 -fopenmp
dnl SunPRO C -xopenmp
dnl Intel C -openmp
dnl SGI C, PGI C -mp
dnl Tru64 Compaq C -omp
dnl IBM C (AIX, Linux) -qsmp=omp
for brand in GCC SunPRO Intel SGI/PGI Compaq IBM; do
case $brand in
GCC)
ac_conditional='defined __GNUC__'
ac_option='-fopenmp' ;;
SunPRO)
ac_conditional='defined __SUNPRO_C || defined __SUNPRO_CC'
ac_option='-xopenmp' ;;
Intel)
ac_conditional='defined __INTEL_COMPILER'
ac_option='-openmp' ;;
SGI/PGI)
ac_conditional='defined __sgi || defined __PGI || defined __PGIC__'
ac_option='-mp' ;;
Compaq)
ac_conditional='defined __DECC || defined __DECCXX'
ac_option='-omp' ;;
IBM)
ac_conditional='defined __xlc__ || defined __xlC__'
ac_option='-qsmp=omp' ;;
esac
if test $brand = GCC; then
if test "$GCC" = yes; then
ac_openmp_result=yes
else
ac_openmp_result=no
fi
else
AC_EGREP_CPP([Brand], [
#if $ac_conditional
Brand
#endif
], [ac_openmp_result=yes], [ac_openmp_result=no])
fi
if test $ac_openmp_result = yes; then
ac_save_CFLAGS=$CFLAGS
CFLAGS="$CFLAGS $ac_option"
AC_LINK_IFELSE([
#ifndef _OPENMP
choke me
#endif
#include <omp.h>
int main () { return omp_get_num_threads (); }
], [ac_cv_prog_cc_openmp=$ac_option])
CFLAGS=$ac_save_CFLAGS
break
fi
done
fi
])
AC_MSG_RESULT([$ac_cv_prog_cc_openmp])
case $ac_cv_prog_cc_openmp in
"none needed" | unsupported)
OPENMP_CFLAGS= ;;
*)
OPENMP_CFLAGS=$ac_cv_prog_cc_openmp ;;
esac
fi
AC_SUBST([OPENMP_CFLAGS])
])
|
