[Bug middle-end/94465] [10 Regression] fnsplit dump file ICEs

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94465

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot 
gnu.org
             Status|UNCONFIRMED                 |ASSIGNED
   Target Milestone|---                         |10.0
   Last reconfirmed|                            |2020-04-03
     Ever confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
The issue is that the SSA name is released:

    arg:1 <ssa_name 0xffffb7ba1480 type <error_mark 0xffffb7b9ed80>
        nothrow
        def_stmt
        version:3 in-free-list>

so we're dumping something that was freed.  Indeed we're dumping
from delete_basic_block and there from cleanup_control_flow_pre
which fails to delete unreachable basic-blocks in postorder
which likely only matters for dumping.