[Bug tree-optimization/97159] segfault in modref_may_conflict

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97159

--- Comment #1 from Tom de Vries <vries at gcc dot gnu.org> ---
Segfaults because tt is NULL:
...
Program received signal SIGSEGV, Segmentation fault.
0x00000000012b1a69 in modref_may_conflict (tt=0x0, ref=0x7fffffffd8d0,
tbaa_p=true)
    at /home/vries/oacc/trunk/source-gcc/gcc/tree-ssa-alias.c:2433
2433      if (tt->every_base)
(gdb)
...

tt comes from summary->loads:
...
(gdb) up
#1  0x00000000012b1da1 in ref_maybe_used_by_call_p_1 (call=0x7ffff7ff43f0, 
    ref=0x7fffffffd8d0, tbaa_p=true)
    at /home/vries/oacc/trunk/source-gcc/gcc/tree-ssa-alias.c:2513
2513                  if (!modref_may_conflict (summary->loads, ref, tbaa_p))
...

and summary looks like:
...
(gdb) p *summary
$2 = {loads = 0x0, stores = 0x0, loads_lto = 0x0, stores_lto = 0x0, finished =
true}
...