Optimize powerpc*-*-linux* e500 hardfp/soft-fp use

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

Continuing the cleanups of libgcc soft-fp configuration for
powerpc*-*-linux* in preparation for implementing
TARGET_ATOMIC_ASSIGN_EXPAND_FENV for soft-float and e500, this patch
optimizes the choice of which functions to build for the e500 cases.

For e500v2, use of hardfp is generally right, except that calls to
__unordsf2 and __unorddf2 are actually generated by GCC from
__builtin_isunordered and so they need to be implemented with soft-fp
to avoid recursively calling themselves.  For e500v1, hardfp is right
for SFmode (except for __unordsf2) but soft-fp for DFmode (and when
using soft-fp, as usual it's best for the conversions between DFmode
and integers all to come directly from soft-fp rather than some coming
from libgcc2.c).  Thus, new variables hardfp_exclusions and
softfp_extras are added that configurations using t-hardfp and
t-softfp can use to achieve the desired effect of selectively mixing
the two sources of functions.

Tested with no regressions for crosses to powerpc-linux-gnuspe (both
e500v1 and e500v2); also checked that the same set of symbols and
versions is exported from shared libgcc before and after the patch.
OK to commit?

2014-10-29  Joseph Myers  <joseph@codesourcery.com>

	* config/t-hardfp (hardfp_exclusions): Document new variable for
	user to define.
	(hardfp_func_list): Exclude functions from $(hardfp_exclusions).
	* config/t-softfp (softfp_extras): Document new variable for user
	to define.
	(softfp_func_list): Add functions from $(softfp_extras).
	* config/rs6000/t-e500v1-fp, config/rs6000/t-e500v2-fp: New files.
	* config.host (powerpc*-*-linux*): For e500v1, use
	rs6000/t-e500v1-fp and t-hardfp; do not use t-softfp-sfdf and
	t-softfp-excl.  For e500v2, use t-hardfp-sfdf, rs6000/t-e500v2-fp
	and t-hardfp; do not use t-softfp-sfdf and t-softfp-excl.

Index: libgcc/config/rs6000/t-e500v1-fp
===================================================================
--- libgcc/config/rs6000/t-e500v1-fp	(revision 0)
+++ libgcc/config/rs6000/t-e500v1-fp	(working copy)
@@ -0,0 +1,32 @@
+# Copyright (C) 2014 Free Software Foundation, Inc.
+
+# This file is part of GCC.
+
+# GCC 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, or (at your option)
+# any later version.
+
+# GCC 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 GCC; see the file COPYING3.  If not see
+# <http://www.gnu.org/licenses/>.
+
+# Use hardfp.c for SFmode (except __unordsf2), soft-fp for DFmode.
+# For SFmode, libgcc2.c functions are used where applicable; for
+# DFmode, they are excluded.
+hardfp_float_modes := sf
+hardfp_int_modes := si
+hardfp_extensions :=
+hardfp_truncations :=
+hardfp_exclusions := unordsf2
+softfp_float_modes := df
+softfp_int_modes := si di
+softfp_extensions := sfdf
+softfp_truncations := dfsf
+softfp_exclude_libgcc2 := n
+softfp_extras := unordsf2
Index: libgcc/config/rs6000/t-e500v2-fp
===================================================================
--- libgcc/config/rs6000/t-e500v2-fp	(revision 0)
+++ libgcc/config/rs6000/t-e500v2-fp	(working copy)
@@ -0,0 +1,26 @@
+# Copyright (C) 2014 Free Software Foundation, Inc.
+
+# This file is part of GCC.
+
+# GCC 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, or (at your option)
+# any later version.
+
+# GCC 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 GCC; see the file COPYING3.  If not see
+# <http://www.gnu.org/licenses/>.
+
+# All operations except __unordsf2 and __unorddf2 can come from hardfp.c.
+hardfp_exclusions := unordsf2 unorddf2
+softfp_float_modes :=
+softfp_int_modes :=
+softfp_extensions :=
+softfp_truncations :=
+softfp_exclude_libgcc2 := n
+softfp_extras := unordsf2 unorddf2
Index: libgcc/config/t-hardfp
===================================================================
--- libgcc/config/t-hardfp	(revision 216787)
+++ libgcc/config/t-hardfp	(working copy)
@@ -32,6 +32,13 @@
 #                    e.g. sfdf
 # hardfp_truncations: a list of truncations between hardware floating-point
 #                     modes, e.g. dfsf
+#
+# If some functions that would otherwise be defined should not be
+# defined by this file (typically because the target would compile
+# certain operations into a call to the libgcc function, which thus
+# needs to be defined elsewhere to use software floating point), also
+# define hardfp_exclusions to be a list of those functions,
+# e.g. unorddf2.
 
 # Functions parameterized by a floating-point mode M.
 hardfp_func_bases := addM3 subM3 negM2 mulM3 divM3
@@ -50,6 +57,8 @@
 hardfp_func_list += $(foreach pair, $(hardfp_truncations), \
 		    	      $(subst M,$(pair),truncM2))
 
+hardfp_func_list := $(filter-out $(hardfp_exclusions),$(hardfp_func_list))
+
 # Regexp for matching a floating-point mode.
 hardfp_mode_regexp := $(shell echo $(hardfp_float_modes) | sed 's/ /\\|/g')
 
Index: libgcc/config/t-softfp
===================================================================
--- libgcc/config/t-softfp	(revision 216787)
+++ libgcc/config/t-softfp	(working copy)
@@ -31,6 +31,10 @@
 # is a soft-float mode; for example, sftf where sf is hard-float and
 # tf is soft-float.
 #
+# If some additional functions should be built that are not implied by
+# the above settings, also define softfp_extras as a list of those
+# functions, e.g. unorddf2.
+#
 # If the libgcc2.c functions should not be replaced, also define:
 #
 # softfp_exclude_libgcc2 := y
@@ -61,7 +65,8 @@
               $(foreach i,$(softfp_int_modes), \
                           $(softfp_floatint_funcs))) \
   $(foreach e,$(softfp_extensions),extend$(e)2) \
-  $(foreach t,$(softfp_truncations),trunc$(t)2)
+  $(foreach t,$(softfp_truncations),trunc$(t)2) \
+  $(softfp_extras)
 
 ifeq ($(softfp_exclude_libgcc2),y)
 # This list is taken from mklibgcc.in and doesn't presently allow for
Index: libgcc/config.host
===================================================================
--- libgcc/config.host	(revision 216787)
+++ libgcc/config.host	(working copy)
@@ -1000,9 +1000,12 @@
 	soft)
 		tmake_file="${tmake_file} t-softfp-sfdf t-softfp"
 		;;
-	e500v1|e500v2)
-		tmake_file="${tmake_file} t-softfp-sfdf t-softfp-excl t-softfp"
+	e500v1)
+		tmake_file="${tmake_file} rs6000/t-e500v1-fp t-softfp t-hardfp"
 		;;
+	e500v2)
+		tmake_file="${tmake_file} t-hardfp-sfdf rs6000/t-e500v2-fp t-softfp t-hardfp"
+		;;
 	*)
 		echo "Unknown ppc_fp_type $ppc_fp_type" 1>&2
 		exit 1

-- 
Joseph S. Myers
joseph@codesourcery.com