Imported http://autoconf-archive.cryp.to/ release 2007-02-14.

1 files changed, 185 insertions, 0 deletions

diff --git a/m4/ax_cc_maxopt.m4 b/m4/ax_cc_maxopt.m4
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+##### 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.
+#
+# LAST MODIFICATION
+#
+#   2005-05-30
+#
+# COPYLEFT
+#
+#   Copyright (c) 2005 Steven G. Johnson <stevenj@alum.mit.edu>
+#   Copyright (c) 2005 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 2 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, write to the Free Software
+#   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+#   02111-1307, USA.
+#
+#   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 Macro 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 $icc_archflag"
+          fi
+        fi
+	;;
+
+    gnu)
+     # default optimization flags for gcc on all systems
+     CFLAGS="-O3 -fomit-frame-pointer"
+
+     # -malign-double for x86 systems
+     AX_CHECK_COMPILER_FLAGS(-malign-double, CFLAGS="$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
+])