Re: [PATCH] Fix up __builtin_setjmp_receiver handling (PR c++/60082)

[Jakub Jelinek <jakub at redhat dot com>]

On Thu, Feb 06, 2014 at 10:13:25AM +0100, Richard Biener wrote:
> > trunk?  Alternatively we could special case BUILT_IN_SETJMP_RECEIVER instead
> > in call_can_make_abnormal_goto, there is probably no need to have AB edge
> > out of __builtin_setjmp_receiver, we already have one out of
> > __builtin_setjmp_setup and receiver is really expanded just to load of frame
> > pointer, so it doesn't jump anywhere.
> > 
> > Note that this fixes both the CK tests on x86_64-linux, on i686-linux
> > neither of them timeout, but catch_exc.cc still fails:
> >  FAIL: g++.dg/cilk-plus/CK/catch_exc.cc  -O1 -fcilkplus execution test
> >  FAIL: g++.dg/cilk-plus/CK/catch_exc.cc  -O3 -fcilkplus execution test
> >  FAIL: g++.dg/cilk-plus/CK/catch_exc.cc  -g -O2 -fcilkplus execution test
> 
> I don't like special-casing BUILT_IN_SETJMP_RECEIVER - we don't

Not even in call_can_make_abnormal_goto?  I mean, as we split
__builtin_setjmp into __builtin_setjmp{_setup,_receiver} and the former
has abnormal edge out of it, there is no need to have another abnormal edge
out of the receiver.

> currently have a suitable exported stmt_starts_bb_p () (the existing
> one is too special), but similar to is_ctrl_altering_stmt we could
> add a is_ctrl_receiving_stmt that covers nonlocal labels and other

Yes, that works for me.  I wondered if insert_backedge_copies wouldn't do
harm if it inserts the assignments before normal setjmp call or other
call that returns twice.

> stmts we add abnormal edges to.  Btw, why isn't BUILT_IN_SETJMP_RECEIVER
> ECF_RETURNS_TWICE?

See PR60003, #c5 in particular which really didn't work at all, and Eric's
preference in #c8.

	Jakub