Index: gsl-1.15/configure.ac =================================================================== --- gsl-1.15.orig/configure.ac +++ gsl-1.15/configure.ac @@ -381,6 +381,30 @@ AC_SUBST(HAVE_OPENBSD_IEEE_INTERFACE) AC_SUBST(HAVE_DARWIN_IEEE_INTERFACE) AC_SUBST(HAVE_DARWIN86_IEEE_INTERFACE) +dnl check for compiler flags to disable use of FMA +save_cflags="$CFLAGS" +AC_CACHE_CHECK([for compiler flags to disable use of FMA], ac_cv_c_fma_flags, +[ +if test X"$GCC" = Xyes; then + fma_flags='-ffp-contract=off' +else + fma_flags= +fi +if test X"$fma_flags" != X; then + CFLAGS="$fma_flags $CFLAGS" + AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[int +foo;]])],[ac_cv_c_fma_flags="$fma_flags"],[ac_cv_c_fma_flags="none"]) +else + ac_cv_c_fma_flags="none" +fi]) + +if test "$ac_cv_c_fma_flags" != "none" ; then + CFLAGS="$ac_cv_c_fma_flags $save_cflags" +else + CFLAGS="$save_cflags" +fi + + dnl Check for IEEE control flags save_cflags="$CFLAGS"