> On 05/14/2015 01:24 PM, Segher Boessenkool wrote:
> > On Thu, May 14, 2015 at 12:31:40PM -0600, Jeff Law wrote:
> >> On 05/14/2015 11:36 AM, Segher Boessenkool wrote:
> >>> The alternative that allows move to mem is alt 1, but it thinks the operand
> >>> doesn't match (it is "B" or "W"), it picks alt 0, loop, everyone unhappy.
> >>>
> >>> "B" should match it seems?
> >>>
> >>> (Why does IRA think r56 should be in memory?  Yeah, good question.)
> >> Independent of that, if a reg-reg move generated by LRA (which is really
> >> a mem->reg or reg->mem) blows up on this target for some reason, then
> >> that needs to be addressed independently of whether or not IRA might
> >> have made a bad choice for which pseudo to spill.
> >
> > Yes.  It probably is because of the "volatile" I inserted for it
> > to fail at all, anyway.
> >
> > Changing constraints ABWef to be define_memory_constraint (instead of
> > define_constraint) makes this testcase pass.  It also makes the build
> > pass (it failed before; 90 reloads in libgcc).
> >
> > Pretty miserable code for those memory accesses, but hey, better
> > than an ICE ;-)
> Makes sense if it wasn't defined as a memory constraint that LRA would
> be having trouble -- odds are reload would have barf'd at some point too.
> 
> The only difference is I'm actually still better at understanding what
> reload's doing from its dumps than LRA.  It's hard to throw away decades
> of retained knowledge earned the hard way.
> 
> James, can you go ahead and make that change to ABWef and enable LRA and
> commit your changes to the trunk?

OK, ABWef changes made, and fixed a couple of pattern holes that they exposed.
Added a new target option "-mlra" to enable LRA.  Updated invoking.texi.

Please can someone commit this, if appropriate, as I do not have write access to the tree.

Thanks very much. ChangeLog entry:

2015-05-14  James Bowman  <james.bowman@ftdichip.com>

        * configure.ac: FT32 target added
        * libgcc/config.host: FT32 target added
        * gcc/config/ft32/: FT32 target added
        * libgcc/config/ft32/: FT32 target added
        * gcc/doc/install.texi, invoke.texi, md.texi: FT32 details added
        * gcc/doc/contrib.texi: self added
        * contrib/config-list.mk: FT32 target added
        * configure: Regenerated

--
James Bowman
FTDI Open Source Liaison