# =========================================================================== # www.gnu.org/software/autoconf-archive/ax_gcc_archflag.html # =========================================================================== # # SYNOPSIS # # AX_GCC_ARCHFLAG(, [ACTION-SUCCESS], [ACTION-FAILURE]) # # DESCRIPTION # # This macro tries to guess the “native” arch corresponding to the target # architecture for use with gcc's -march=arch or -mtune=arch flags. If # found, the cache variable $ax_cv_gcc_archflag is set to this flag and # ACTION-SUCCESS is executed; otherwise $ax_cv_gcc_archflag is is set to # “unknown” and ACTION-FAILURE is executed. The default ACTION-SUCCESS is # to add $ax_cv_gcc_archflag to the end of $CFLAGS. # # PORTABLE? should be either [yes] (default) or [no]. In the former case, # the flag is set to -mtune (or equivalent) so that the architecture is # only used for tuning, but the instruction set used is still portable. In # the latter case, the flag is set to -march (or equivalent) so that # architecture-specific instructions are enabled. # # The user can specify –with-gcc-arch=<arch> in order to override the # macro's choice of architecture, or –without-gcc-arch to disable this. # # When cross-compiling, or if $CC is not gcc, then ACTION-FAILURE is # called unless the user specified –with-gcc-arch manually. # # Requires macros: AX_CHECK_COMPILER_FLAGS, AX_GCC_X86_CPUID # # (The main emphasis here is on recent CPUs, on the principle that doing # high-performance computing on old hardware is uncommon.) # # LICENSE # # Copyright © 2008 Steven G. Johnson <stevenj@alum.mit.edu> # Copyright © 2008 Matteo Frigo # # This program is free software: you can redistribute it and/or modify it # under the terms of the GNU General Public License as published by the # Free Software Foundation, either version 3 of the License, or (at your # option) any later version. # # This program is distributed in the hope that it will be useful, but # WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General # Public License for more details. # # You should have received a copy of the GNU General Public License along # with this program. If not, see <www.gnu.org/licenses/>. # # As a special exception, the respective Autoconf Macro's copyright owner # gives unlimited permission to copy, distribute and modify the configure # scripts that are the output of Autoconf when processing the Macro. You # need not follow the terms of the GNU General Public License when using # or distributing such scripts, even though portions of the text of the # Macro appear in them. The GNU General Public License (GPL) does govern # all other use of the material that constitutes the Autoconf Macro. # # This special exception to the GPL applies to versions of the Autoconf # Macro released by the Autoconf Archive. When you make and distribute a # modified version of the Autoconf Macro, you may extend this special # exception to the GPL to apply to your modified version as well.
serial 8
AC_DEFUN(, [AC_REQUIRE() AC_REQUIRE()
AC_ARG_WITH(gcc-arch, [m4_default([$2], [CFLAGS="$CFLAGS $ax_cv_gcc_archflag"])
fi ])