# =========================================================================== # www.gnu.org/software/autoconf-archive/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_COMPILE_FLAG, AX_COMPILER_VENDOR, # AX_GCC_ARCHFLAG, AX_GCC_X86_CPUID. # # 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.
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AC_DEFUN(, [ AC_REQUIRE() AC_REQUIRE() AC_REQUIRE()
AC_ARG_ENABLE(portable-binary, [AS_HELP_STRING(, [disable compiler optimizations that would produce unportable binaries])],
acx_maxopt_portable=$enableval, acx_maxopt_portable=no)
# Try to determine “good” native compiler flags if none specified via CFLAGS if test “x$ac_test_CFLAGS” = “x”; then
case $ax_cv_c_compiler_vendor in
dec) CFLAGS="$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="$CFLAGS -native -fast -xO5 -dalign"
if test "x$acx_maxopt_portable" = xyes; then
CFLAGS="$CFLAGS -xarch=generic"
fi;;
hp) CFLAGS="$CFLAGS +Oall +Optrs_ansi +DSnative"
if test "x$acx_maxopt_portable" = xyes; then
CFLAGS="$CFLAGS +DAportable"
fi;;
ibm) if test "x$acx_maxopt_portable" = xno; then
xlc_opt="-qarch=auto -qtune=auto"
else
xlc_opt="-qtune=auto"
fi
AX_CHECK_COMPILE_FLAG($xlc_opt,
CFLAGS="$CFLAGS -O3 -qansialias -w $xlc_opt",
[CFLAGS="$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="$CFLAGS -O3 -ansi_alias"
if test "x$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: 6c65746e:49656e69) # Intel
case $ax_cv_gcc_x86_cpuid_1 in
*0?6[[78ab]]?:*:*:*|?6[[78ab]]?:*:*:*|6[[78ab]]?:*:*:*) icc_flags="-xK" ;;
*0?6[[9d]]?:*:*:*|?6[[9d]]?:*:*:*|6[[9d]]?:*:*:*|*1?65?:*:*:*) icc_flags="-xSSE2 -xB -xK" ;;
*0?6e?:*:*:*|?6e?:*:*:*|6e?:*:*:*) icc_flags="-xSSE3 -xP -xO -xB -xK" ;;
*0?6f?:*:*:*|?6f?:*:*:*|6f?:*:*:*|*1?66?:*:*:*) icc_flags="-xSSSE3 -xT -xB -xK" ;;
*1?6[[7d]]?:*:*:*) icc_flags="-xSSE4.1 -xS -xT -xB -xK" ;;
*1?6[[aef]]?:*:*:*|*2?6[[5cef]]?:*:*:*) icc_flags="-xSSE4.2 -xS -xT -xB -xK" ;;
*2?6[[ad]]?:*:*:*) icc_flags="-xAVX -SSE4.2 -xS -xT -xB -xK" ;;
*3?6[[ae]]?:*:*:*) icc_flags="-xCORE-AVX-I -xAVX -SSE4.2 -xS -xT -xB -xK" ;;
*3?6[[cf]]?:*:*:*|*4?6[[56]]?:*:*:*) icc_flags="-xCORE-AVX2 -xCORE-AVX-I -xAVX -SSE4.2 -xS -xT -xB -xK" ;;
*000?f[[346]]?:*:*:*|?f[[346]]?:*:*:*|f[[346]]?:*:*:*) icc_flags="-xSSE3 -xP -xO -xN -xW -xK" ;;
*00??f??:*:*:*|??f??:*:*:*|?f??:*:*:*|f??:*:*:*) icc_flags="-xSSE2 -xN -xW -xK" ;;
esac ;;
esac ;;
esac
if test "x$icc_flags" != x; then
for flag in $icc_flags; do
AX_CHECK_COMPILE_FLAG($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 $icc_archflag"
fi
fi
;;
nvhpc)
# default optimization flags for nvhpc
CFLAGS="$CFLAGS -O3"
;;
gnu)
# default optimization flags for gcc on all systems
CFLAGS="$CFLAGS -O3 -fomit-frame-pointer"
# -malign-double for x86 systems
# LIBFFI_LOCAL: don't do this.
# The testsuite doesn't use these flags and we'll get test failures.
# AX_CHECK_COMPILE_FLAG(-malign-double, CFLAGS="$CFLAGS -malign-double")
# -fstrict-aliasing for gcc-2.95+
AX_CHECK_COMPILE_FLAG(-fstrict-aliasing,
CFLAGS="$CFLAGS -fstrict-aliasing")
# note that we enable "unsafe" fp optimization with other compilers, too
AX_CHECK_COMPILE_FLAG(-ffast-math, CFLAGS="$CFLAGS -ffast-math")
AX_GCC_ARCHFLAG($acx_maxopt_portable)
;;
microsoft)
# default optimization flags for MSVC opt builds
CFLAGS="$CFLAGS -O2"
;;
esac
if test -z "$CFLAGS"; then
echo ""
echo "********************************************************"
echo "* WARNING: Don't know the best CFLAGS for this system *"
echo "* Use ./configure CFLAGS=... to specify your own flags *"
echo "* (otherwise, a default of CFLAGS=-O3 will be used) *"
echo "********************************************************"
echo ""
CFLAGS="$CFLAGS -O3"
fi
AX_CHECK_COMPILE_FLAG($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 ""
])
fi ])