Add --with-arch-32 etc. configure options

["Joseph S. Myers" <joseph at codesourcery dot com>]

This patch adds configure options --with-arch-32 --with-arch-64
--with-cpu-32 --with-cpu-64 --with-tune-32 --with-tune-64, similar to
--with-arch etc. but controlling the defaults separately for 32-bit
and 64-bit code generation.  The option names follow the preferences
expressed at
<http://gcc.gnu.org/ml/gcc-patches/2007-06/msg00257.html>; that thread
also provides further rationale for when this sort of configuration is
of use (if you wish to have a toolchain with a minimum 32-bit CPU that
isn't 64-bit capable, but also with 64-bit support, for example).
This patch only provides an implementation for x86/x86_64;
implementations for each additional target would be essentially
independent.

Tested i686-pc-linux-gnu with these options in use.  OK to commit?

2008-06-03  Joseph Myers  <joseph@codesourcery.com>

	* config.gcc (all_defaults): Add arch_32 arch_64 cpu_32 cpu_64
	tune_32 tune_64.
	(i[34567]86-*-* | x86_64-*-*): Add arch_32 arch_64 cpu_32 cpu_64
	tune_32 tune_64 to supported_defaults.  Allow values not
	supporting 64-bit mode for arch_32, cpu_32 and tune_32 for
	x86_64.  Do not override cpu_32 or cpu_64 values from target name.
	(i[34567]86-*-linux*, i[34567]86-*-solaris2.1[0-9]*): Only default
	with_cpu_64 to generic for 64-bit-supporting configurations, not
	with_cpu.  Remove FIXMEs.
	* doc/install.texi (--with-cpu-32, --with-cpu-64, --with-arch-32,
	--with-arch-64, --with-tune-32, --with-tune-64): Document.
	* config/i386/i386.h (OPT_ARCH32, OPT_ARCH64): Define.
	(OPTION_DEFAULT_SPECS): Add tune_32, tune_64, cpu_32, cpu_64,
	arch_32 and arch_64.

Index: gcc/doc/install.texi
===================================================================
--- gcc/doc/install.texi	(revision 136297)
+++ gcc/doc/install.texi	(working copy)
@@ -1019,14 +1019,23 @@
 This is an alias for @option{--enable-tls=no}.
 
 @item --with-cpu=@var{cpu}
+@itemx --with-cpu-32=@var{cpu}
+@itemx --with-cpu-64=@var{cpu}
 Specify which cpu variant the compiler should generate code for by default.
 @var{cpu} will be used as the default value of the @option{-mcpu=} switch.
 This option is only supported on some targets, including ARM, i386, M68k,
-PowerPC, and SPARC@.
+PowerPC, and SPARC@.  The @option{--with-cpu-32} and
+@option{--with-cpu-64} options specify separate default CPUs for
+32-bit and 64-bit modes; these options are only supported for i386 and
+x86-64.
 
 @item --with-schedule=@var{cpu}
 @itemx --with-arch=@var{cpu}
+@itemx --with-arch-32=@var{cpu}
+@itemx --with-arch-64=@var{cpu}
 @itemx --with-tune=@var{cpu}
+@itemx --with-tune-32=@var{cpu}
+@itemx --with-tune-64=@var{cpu}
 @itemx --with-abi=@var{abi}
 @itemx --with-fpu=@var{type}
 @itemx --with-float=@var{type}
Index: gcc/config.gcc
===================================================================
--- gcc/config.gcc	(revision 136297)
+++ gcc/config.gcc	(working copy)
@@ -1179,13 +1179,13 @@
 			tm_defines="${tm_defines} TARGET_BI_ARCH=1"
 			tmake_file="${tmake_file} i386/t-linux64 i386/t-fprules-softfp64 soft-fp/t-softfp"
 			need_64bit_hwint=yes
-			# FIXME: -m64 for i[34567]86-*-* should be allowed just
-			# like -m32 for x86_64-*-*.
 			case X"${with_cpu}" in
 			Xgeneric|Xcore2|Xnocona|Xx86-64|Xamdfam10|Xbarcelona|Xk8|Xopteron|Xathlon64|Xathlon-fx)
 				;;
 			X)
-				with_cpu=generic
+				if test x$with_cpu_64 = x; then
+					with_cpu_64=generic
+				fi
 				;;
 			*)
 				echo "Unsupported CPU used in --with-cpu=$with_cpu, supported values:" 1>&2
@@ -1308,13 +1308,13 @@
 		tm_defines="${tm_defines} TARGET_BI_ARCH=1"
 		tmake_file="$tmake_file i386/t-crtstuff i386/t-sol2-10"
 		need_64bit_hwint=yes
-		# FIXME: -m64 for i[34567]86-*-* should be allowed just
-		# like -m32 for x86_64-*-*.
 		case X"${with_cpu}" in
 		Xgeneric|Xcore2|Xnocona|Xx86-64|Xamdfam10|Xbarcelona|Xk8|Xopteron|Xathlon64|Xathlon-fx)
 			;;
 		X)
-			with_cpu=generic
+			if test x$with_cpu_64 = x; then
+				with_cpu_64=generic
+			fi
 			;;
 		*)
 			echo "Unsupported CPU used in --with-cpu=$with_cpu, supported values:" 1>&2
@@ -2842,6 +2842,23 @@
       with_cpu="`echo ${target} | sed 's/-.*$//'`"
       ;;
   esac
+
+  # Avoid overriding --with-cpu-32 and --with-cpu-64 values.
+  case ${target} in
+    i[34567]86-*-*|x86_64-*-*)
+      if test x$with_cpu != x; then
+        if test x$with_cpu_32 != x || test x$with_cpu_64 != x; then
+          if test x$with_cpu_32 = x; then
+            with_cpu_32=$with_cpu
+          fi
+          if test x$with_cpu_64 = x; then
+            with_cpu_64=$with_cpu
+          fi
+          with_cpu=
+        fi
+      fi
+      ;;
+  esac
 fi
 
 # Similarly for --with-float
@@ -3052,8 +3069,8 @@
 		;;
 
 	i[34567]86-*-* | x86_64-*-*)
-		supported_defaults="arch cpu tune"
-		for which in arch cpu tune; do
+		supported_defaults="arch arch_32 arch_64 cpu cpu_32 cpu_64 tune tune_32 tune_64"
+		for which in arch arch_32 arch_64 cpu cpu_32 cpu_64 tune tune_32 tune_64; do
 			eval "val=\$with_$which"
 			case ${val} in
 			i386 | i486 \
@@ -3064,8 +3081,14 @@
 			| prescott | pentium-m | pentium4m | pentium3m)
 				case "${target}" in
 				  x86_64-*-*)
-				      echo "CPU given in --with-$which=$val doesn't support 64bit mode." 1>&2
-				      exit 1
+				      case "x$which" in
+					*_32)
+						;;
+					*)
+						echo "CPU given in --with-$which=$val doesn't support 64bit mode." 1>&2
+						exit 1
+						;;
+				      esac
 				      ;;
 				esac
 				# OK
@@ -3392,7 +3415,7 @@
 esac
 
 t=
-all_defaults="abi cpu arch tune schedule float mode fpu divide llsc"
+all_defaults="abi cpu cpu_32 cpu_64 arch arch_32 arch_64 tune tune_32 tune_64 schedule float mode fpu divide llsc"
 for option in $all_defaults
 do
 	eval "val=\$with_$option"
Index: gcc/config/i386/i386.h
===================================================================
--- gcc/config/i386/i386.h	(revision 136297)
+++ gcc/config/i386/i386.h	(working copy)
@@ -478,13 +478,27 @@
 #define HAVE_LOCAL_CPU_DETECT
 #endif
 
+#if TARGET_64BIT_DEFAULT
+#define OPT_ARCH64 "!m32"
+#define OPT_ARCH32 "m32"
+#else
+#define OPT_ARCH64 "m64"
+#define OPT_ARCH32 "!m64"
+#endif
+
 /* Support for configure-time defaults of some command line options.
    The order here is important so that -march doesn't squash the
    tune or cpu values.  */
 #define OPTION_DEFAULT_SPECS					   \
   {"tune", "%{!mtune=*:%{!mcpu=*:%{!march=*:-mtune=%(VALUE)}}}" }, \
+  {"tune_32", "%{" OPT_ARCH32 ":%{!mtune=*:%{!mcpu=*:%{!march=*:-mtune=%(VALUE)}}}}" }, \
+  {"tune_64", "%{" OPT_ARCH64 ":%{!mtune=*:%{!mcpu=*:%{!march=*:-mtune=%(VALUE)}}}}" }, \
   {"cpu", "%{!mtune=*:%{!mcpu=*:%{!march=*:-mtune=%(VALUE)}}}" },  \
-  {"arch", "%{!march=*:-march=%(VALUE)}"}
+  {"cpu_32", "%{" OPT_ARCH32 ":%{!mtune=*:%{!mcpu=*:%{!march=*:-mtune=%(VALUE)}}}}" }, \
+  {"cpu_64", "%{" OPT_ARCH64 ":%{!mtune=*:%{!mcpu=*:%{!march=*:-mtune=%(VALUE)}}}}" }, \
+  {"arch", "%{!march=*:-march=%(VALUE)}"},			   \
+  {"arch_32", "%{" OPT_ARCH32 ":%{!march=*:-march=%(VALUE)}}"},	   \
+  {"arch_64", "%{" OPT_ARCH64 ":%{!march=*:-march=%(VALUE)}}"},
 
 /* Specs for the compiler proper */
 

-- 
Joseph S. Myers
joseph@codesourcery.com