[Bug target/84272] [8 Regression] AddressSanitizer: heap-use-after-free ../../gcc/config/aarch64/cortex-a57-fma-steering.c:519 in fma_node::get_parity()

["ktkachov at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84272

--- Comment #5 from ktkachov at gcc dot gnu.org ---
(In reply to Jakub Jelinek from comment #4)
> Created attachment 43382 [details]
> gcc8-pr84272-2.patch
> 
> Or defer deletion of all the fma_nodes until the end, whether they are root
> or not.  I'd fear that even removing just non-root nodes might mean the
> following processing of the children might still look at the parent nodes.
> 
> Untested as well.  I'd appreciate feedback from the pass author.

Thomas (the author of the pass) tells me that he prefers the second approach
but he has a few extra comments on the patch that he'll provide later today.
In the meantime I can help with testing the patch on aarch64. Thanks for
investigating this Jakub.

--- Comment #6 from ktkachov at gcc dot gnu.org ---
(In reply to Jakub Jelinek from comment #4)
> Created attachment 43382 [details]
> gcc8-pr84272-2.patch
> 
> Or defer deletion of all the fma_nodes until the end, whether they are root
> or not.  I'd fear that even removing just non-root nodes might mean the
> following processing of the children might still look at the parent nodes.
> 
> Untested as well.  I'd appreciate feedback from the pass author.

Thomas (the author of the pass) tells me that he prefers the second approach
and he has a few extra comments on the patch that he'll provide later today.
In the meantime I can help with testing the patch on aarch64. Thanks for
investigating this Jakub.