# =========================================================================== # http://autoconf-archive.cryp.to/ax_cc_maxopt.html # =========================================================================== # # SYNOPSIS # # AX_CC_MAXOPT # # DESCRIPTION # # Try to turn on "good" C optimization flags for various compilers and # architectures, for some definition of "good". (In our case, good for # FFTW and hopefully for other scientific codes. Modify as needed.) # # The user can override the flags by setting the CFLAGS environment # variable. The user can also specify --enable-portable-binary in order to # disable any optimization flags that might result in a binary that only # runs on the host architecture. # # Note also that the flags assume that ANSI C aliasing rules are followed # by the code (e.g. for gcc's -fstrict-aliasing), and that floating-point # computations can be re-ordered as needed. # # Requires macros: AX_CHECK_COMPILER_FLAGS, AX_COMPILER_VENDOR, # AX_GCC_ARCHFLAG, AX_GCC_X86_CPUID. # # LICENSE # # Copyright (c) 2008 Steven G. Johnson # Copyright (c) 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 . # # 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. AC_DEFUN([AX_CC_MAXOPT], [ AC_REQUIRE([AC_PROG_CC]) AC_REQUIRE([AX_COMPILER_VENDOR]) AC_REQUIRE([AC_CANONICAL_HOST]) AC_ARG_ENABLE(portable-binary, [AC_HELP_STRING([--enable-portable-binary], [disable compiler optimizations that would produce unportable binaries])], acx_maxopt_portable=$withval, acx_maxopt_portable=no) # Try to determine "good" native compiler flags if none specified via CFLAGS if test "$ac_test_CFLAGS" != "set"; then CFLAGS="" case $ax_cv_c_compiler_vendor in dec) CFLAGS="-newc -w0 -O5 -ansi_alias -ansi_args -fp_reorder -tune host" if test "x$acx_maxopt_portable" = xno; then CFLAGS="$CFLAGS -arch host" fi;; sun) CFLAGS="-native -fast -xO5 -dalign" if test "x$acx_maxopt_portable" = xyes; then CFLAGS="$CFLAGS -xarch=generic" fi;; hp) CFLAGS="+Oall +Optrs_ansi +DSnative" if test "x$acx_maxopt_portable" = xyes; then CFLAGS="$CFLAGS +DAportable" fi;; ibm) if test "x$acx_maxopt_portable" = xno; then xlc_opt="-qarch=auto -qtune=auto" else xlc_opt="-qtune=auto" fi AX_CHECK_COMPILER_FLAGS($xlc_opt, CFLAGS="-O3 -qansialias -w $xlc_opt", [CFLAGS="-O3 -qansialias -w" echo "******************************************************" echo "* You seem to have the IBM C compiler. It is *" echo "* recommended for best performance that you use: *" echo "* *" echo "* CFLAGS=-O3 -qarch=xxx -qtune=xxx -qansialias -w *" echo "* ^^^ ^^^ *" echo "* where xxx is pwr2, pwr3, 604, or whatever kind of *" echo "* CPU you have. (Set the CFLAGS environment var. *" echo "* and re-run configure.) For more info, man cc. *" echo "******************************************************"]) ;; intel) CFLAGS="-O3 -ansi_alias" if test "x$acx_maxopt_portable" = xno; then icc_archflag=unknown icc_flags="" case $host_cpu in i686*|x86_64*) # icc accepts gcc assembly syntax, so these should work: AX_GCC_X86_CPUID(0) AX_GCC_X86_CPUID(1) case $ax_cv_gcc_x86_cpuid_0 in # see AX_GCC_ARCHFLAG *:756e6547:*:*) # Intel case $ax_cv_gcc_x86_cpuid_1 in *6a?:*[[234]]:*:*|*6[[789b]]?:*:*:*) icc_flags="-xK";; *f3[[347]]:*:*:*|*f4[1347]:*:*:*) icc_flags="-xP -xN -xW -xK";; *f??:*:*:*) icc_flags="-xN -xW -xK";; esac ;; esac ;; esac if test "x$icc_flags" != x; then for flag in $icc_flags; do AX_CHECK_COMPILER_FLAGS($flag, [icc_archflag=$flag; break]) done fi AC_MSG_CHECKING([for icc architecture flag]) AC_MSG_RESULT($icc_archflag) if test "x$icc_archflag" != xunknown; then CFLAGS="$CFLAGS $icc_archflag" fi fi ;; gnu) # default optimization flags for gcc on all systems # 2009-07-30 JB Langston # removed -fomit-frame-pointer due to incompatibility with SFFE CFLAGS="-O3" # -malign-double for x86 systems AX_CHECK_COMPILER_FLAGS(-malign-double, CFLAGS="$CFLAGS -malign-double") # -fstrict-aliasing for gcc-2.95+ AX_CHECK_COMPILER_FLAGS(-fstrict-aliasing, CFLAGS="$CFLAGS -fstrict-aliasing") # note that we enable "unsafe" fp optimization with other compilers, too AX_CHECK_COMPILER_FLAGS(-ffast-math, CFLAGS="$CFLAGS -ffast-math") AX_GCC_ARCHFLAG($acx_maxopt_portable) ;; esac if test -z "$CFLAGS"; then echo "" echo "********************************************************" echo "* WARNING: Don't know the best CFLAGS for this system *" echo "* Use ./configure CFLAGS=... to specify your own flags *" echo "* (otherwise, a default of CFLAGS=-O3 will be used) *" echo "********************************************************" echo "" CFLAGS="-O3" fi AX_CHECK_COMPILER_FLAGS($CFLAGS, [], [ echo "" echo "********************************************************" echo "* WARNING: The guessed CFLAGS don't seem to work with *" echo "* your compiler. *" echo "* Use ./configure CFLAGS=... to specify your own flags *" echo "********************************************************" echo "" CFLAGS="" ]) fi ])