[Bug tree-optimization/67282] New: Wrong code with -floop-nest-optimize

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67282

            Bug ID: 67282
           Summary: Wrong code with -floop-nest-optimize
           Product: gcc
           Version: 5.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mpolacek at gcc dot gnu.org
  Target Milestone: ---

I think that we're generating a wrong code when using -O2 -floop-nest-optimize:

double A[64][64];
double C[64][64];

int
main ()
{
  int i, j, k;

  for (i = 0; i < 64; i++)
    for (j = 0; j < 64; j++)
      for (k = 0; k < 64; k++)
        C[i][j] = A[i][k];
}

$ ./a.out 
Segmentation fault (core dumped)

It doesn't segv if I use -frapv/-fsanitize=undefined/...

Might be related to PR66980.