Hello, gcc can be configured with an "e500v2" cpu target name, conveying SPE with double precision floats.
config.gcc already has a provision for a good default
cpu selection for SPE with double precision floats
when the latter is explicitly requested with an explicit
--enable command line option. This is:
# If there is no $with_cpu option, try to infer one from ${target}.
# This block sets nothing except for with_cpu.
...
case ${target} in
...
powerpc*-*-*spe*)
if test x$enable_e500_double = xyes; then
with_cpu=8548
else
with_cpu=8540
fi
;;
The attached patch is a proposal to refine this to select 8548 also
when we were configured for an e500v2 target cpu (canonicalized to
match powerpc-*spe), regardless of enable_e500_double.
We have been using something like this in production for a few
years in-house, lately with gcc-6 based toolchains for VxWorks or
bareboard configurations.
I also checked that
- e500v2-wrs-vxworks builds work with gcc-7, that the default cpu is
indeed properly set to 8548, and that the built toolchains pass Ada
ACATS tests for a couple of runtime library variants (kernel and rtp).
- a mainline build for powerpc-eabispe without --enable-e500-double
defaults to 8540
- a mainline build for powerpc-eabispe with --enable-e500-double
defaults to 8548
- a mainline build for e500v2-wrs-vxworks without --enable-e500-double
defaults to 8548
OK to commit ?
Thanks in advance
2017-08-31 Olivier Hainque <hain...@adacore.com>
* gcc/config.gcc (powerpc*-*-*spe*): Pick 8548 as the
default with_cpu for an e500v2 target cpu name, in addition
to --enable-e500-double.
spe-default-cpu.diff
Description: Binary data
