[Bug middle-end/67649] trunk build with valgrind fail in get_def_blocks_for

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67649

--- Comment #10 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
A gave your patch a quick spin on gcc112 (compile farm machine).
It fixes the issue.