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

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.

	* 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.

From-SVN: r216835

1 files changed, 6 insertions, 1 deletions

diff --git a/libgcc/config/t-softfp b/libgcc/config/t-softfp
index 456fdce..43e0b4d 100644
--- a/libgcc/config/t-softfp
+++ b/libgcc/config/t-softfp
@@ -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 @@ softfp_func_list := \
               $(foreach i,$(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