[Bug tree-optimization/50644] ICE in set_is_used added today

[matz at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50644

--- Comment #8 from Michael Matz <matz at gcc dot gnu.org> 2011-10-20 08:14:45 UTC ---
Andi, the patch you bisected transformed a pre-existing bug into a segfault. 
Reverting it wouldn't fix anything.
You could try the stab-in-the-dark patch from PR50741, but if that doesn't help
I don't see how to make progress here without somebody who sees the problem to
go into gdb and do a 'p debug_tree(var)' on a cc1 that has
enough debuginfo for var to still contain a useful value.