[Bug middle-end/105346] [11/12 Regression] -Wno-free-nonheap-object false positive (on Bison-generated grammar code)

[jakub at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105346

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with r11-5732-gdce6c58db87ebf7f4477bd3126228e73e4eeee97
The IL at -O0 -Wall looks during waccess pass like:
void foo ()
{
  char * bufp;
  char buf[20];

  <bb 2> :
  bufp_2 = &buf;
  if (&buf != bufp_2)
    goto <bb 3>; [INV]
  else
    goto <bb 4>; [INV]

  <bb 3> :
  __builtin_free (bufp_2);

  <bb 4> :
  buf ={v} {CLOBBER(eol)};
  return;

}

So, I think the waccess pass must be walking SSA_NAME_DEF_STMT to figure out it
is a free of non-heap.  Either it shouldn't do that at -O0, or it should only
walk them when they are in the same bb as the free call, or it needs to be able
to detect also conditionals like the above.