[Bug target/111403] New: LoongArch: Wrong code with -O -mlasx -fopenmp-simd

["xry111 at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111403

            Bug ID: 111403
           Summary: LoongArch: Wrong code with -O -mlasx -fopenmp-simd
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: xry111 at gcc dot gnu.org
  Target Milestone: ---

Testcase:

struct S
{
  int s;
  S () : s (0) {}
  ~S () {}
  S (const S &x) { s = x.s; }
  S &
  operator= (const S &x)
  {
    s = x.s;
    return *this;
  }
};

S r, a[1024], b[1024];

#pragma omp declare reduction(+ : S : omp_out.s += omp_in.s)

__attribute__ ((noipa)) void
foo (S *a, S *b)
{
#pragma omp simd reduction(inscan, + : r)
  for (int i = 0; i < 1024; i++)
    {
      r.s += a[i].s;
#pragma omp scan inclusive(r)
      b[i] = r;
    }
}

int
main ()
{
  S s;
  for (int i = 0; i < 1024; ++i)
    {
      a[i].s = i;
      b[i].s = -1;
    }
  foo (a, b);
  if (r.s != 1024 * 1023 / 2)
    __builtin_abort ();
  return 0;
}

$ g++ t.cc -O -mlasx -fopenmp-simd
$ ./a.out
Aborted (core dumped)