[Bug c/88737] RFE: Track ownership moves

[glisse at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88737

--- Comment #5 from Marc Glisse <glisse at gcc dot gnu.org> ---
(In reply to rguenther@suse.de from comment #3)
> Indeed.  So it would be
> 
>  *a = {CLOBBER};
> 
> which is of course somewhat difficult since we do not know the size
> of the object pointed to.

One thing we discussed before is having a pass (like FRE?) transform the read
*a into an uninitialized default-def ssa_name when it notices that the previous
must-alias/clobber write is free (except that free is not considered a
write/clobber IIRC).