[Bug middle-end/107679] [13 Regression] ICE in maybe_register_def, at tree-into-ssa.cc:1914

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107679

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|fortran                     |middle-end
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
             Status|NEW                         |ASSIGNED
           Priority|P4                          |P3

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Kind-of, yes.  Somehow 'z' got marked for renaming, probably because we removed
a TREE_ADDRESABLE flag.  The SSA rewrite wants to replace

  <bb 2> [local count: 1073741824]:
  z ={v} {CLOBBER};
  return;

with an "uninitialized" def, but for PARM_DECLs the default def would be
the actual parameter value.  There's nothing wrong with clobbering 'z'
I think, just the into-ssa code isn't prepared for this - the fix would be
to create an anonymous default def in this case.