https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79432
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
We gimplify this to
fn2 ()
{
int a;
_1 = fn1 ();
_2 = vfork ();
a = _1 + _2;
}
and at CFG construction time try to "fixup" via
fn2 ()
{
int D.1803;
int D.1802;
int a;
<bb 2> [0.00%]:
D.1802 = fn1 ();
<bb 3> [0.00%]:
_1 = D.1802;
<bb 4> [0.00%]:
D.1803 = vfork ();
goto <bb 6>; [0.00%]
<bb 5> [0.00%]:
ABNORMAL_DISPATCHER (0);
<bb 6> [0.00%]:
_2 = D.1803;
a = _1 + _2;
return;
}
this deals with the abnormal outgoing edges but not the abnormal incoming
edges. That is, we do not replace _1 with D.1802 everywhere but just
adjust it across the call/result set split. Note that before into-SSA
we do not have SSA operands set up and thus can't easily walk immediate
uses of _1.
I believe the issue does not only exist for LHS of stmts that can do abnormal
control flow but any SSA defs that have uses live across such calls. So
a more sustainable fix than
r146168 | rguenth | 2009-04-16 12:45:18 +0200 (Thu, 16 Apr 2009) | 6 lines
2009-04-16 Richard Guenther <rguent...@suse.de>
PR middle-end/39625
* tree-cfg.c (make_blocks): Split statements with to-be
abnormal SSA names on the lhs.
might be to deal with the situation in into-SSA...
