[Bug tree-optimization/79334] New: Segfault on tree loop hoisting

[amodra at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79334

            Bug ID: 79334
           Summary: Segfault on tree loop hoisting
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: amodra at gmail dot com
  Target Milestone: ---

Found when looking for a testcase that could trigger a similar problem to
pr72986 for equivalences created in ira using validate_equiv_mem.  Instead I
found a tree optimization problem, if the testcase is valid.  Goes wrong in
134t.pre, a regression from gcc-4.0

Compile -m32 -O2 on x86_64-linux.

static int d[][8] = {};
extern void func_that_exits (int);

int
main (void)
{
  int e;
  while (1)
    {
      func_that_exits (e);
      e = d[300000000000000000][0];
    }
  return 0;
}