http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57067
Bug #: 57067
Summary: Missing control flow edges for setjmp/longjmp
Classification: Unclassified
Product: gcc
Version: 4.9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: kreb...@gcc.gnu.org
The fix for PR56982 adds abnormal control flow edges from function calls to a
setjmp call in the same function. Unfortunately these edges do not survive
until RTL so that the RTL passes might still do the wrong thing.
The edges are removed in gimple_expand_cfg:
/* At the moment not all abnormal edges match the RTL
representation. It is safe to remove them here as
find_many_sub_basic_blocks will rediscover them.
In the future we should get this fixed properly. */
if ((e->flags & EDGE_ABNORMAL)
&& !(e->flags & EDGE_SIBCALL))
remove_edge (e);
else
ei_next (&ei);
find_many_sub_basic_blocks needs a fix to add them back as well.
I don't have a testcase for GCC head. The testcase I have fails only with GCC
4.4: http://gcc.gnu.org/ml/gcc/2013-04/msg00237.html
In this case the RTL scheduler pass generates broken code due to the missing
control flow info. I think this could potentially happen with GCC head as
well.
