https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64922
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P3 |P1
Status|UNCONFIRMED |NEW
Last reconfirmed| |2015-02-03
CC| |hubicka at gcc dot gnu.org
Target Milestone|--- |5.0
Ever confirmed|0 |1
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Goes away with -fno-devirtualize or -fno-devirtualize-speculatively.
Looking at the dumps, after IPA we have:
[pol6.C:39:3] Head::parse (_33, _30);
call (looks fine), but instead of the 3 expected
[pol6.C:39:3] Code_Block::parse (_36, _30);
[pol6.C:39:3] Code_Block::parse (_36, _30);
[pol6.C:39:3] Code_Block::parse (_36, _30);
calls that show e.g. with -fno-devirtualize-speculatively we instead have:
[pol6.C:39:3] __builtin_unreachable (_36, _30);
[pol6.C:39:3] __builtin_unreachable (_36, _30);
[pol6.C:39:3] __builtin_unreachable (_36, _30);
and no wonder everything goes wrong afterwards.
I don't see why IPA devirtualization thinks something is wrong on the
Code_Block::parse calls. And, because for these __builtin_unreachable calls
IPA doesn't strip the undesirable arguments, it isn't transformed even with
-fsanitize=undefined into __ubsan_handle_unreachable (), which would make it
far easier to figure this out.
Honza, can you please have a look?
