[Bug regression/71575] New: internal compiler error: in copy_cond_phi_nodes, at graphite-isl-ast-to-gimple.c:2500

[lluixhi at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71575

            Bug ID: 71575
           Summary: internal compiler error: in copy_cond_phi_nodes, at
                    graphite-isl-ast-to-gimple.c:2500
           Product: gcc
           Version: 6.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: regression
          Assignee: unassigned at gcc dot gnu.org
          Reporter: lluixhi at gmail dot com
  Target Milestone: ---

Reduced Testcase:
void w(int x, double *y)
{
    int i, j;
    double a;
    double c[32];

    for (i = 0; i < x; i++) {
        for (j = 0; j < x - i; j++) {
            c[j] = y[i];
        }
        y[i] = a;
        a += c[0] + y[i];
    }
}

void v(int x, double *y)
{
    w(x, y);
}

on amd64 with -O2 -floop-nest-optimize

test.c: In function 'w':
test.c:1:6: internal compiler error: in copy_cond_phi_nodes, at
graphite-isl-ast-to-gimple.c:2500
 void w(int x, double *y)
      ^
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

I have the pull request from pr69068 applied.