[Bug c/70550] New: -Wuninitialized false positives in OpenMP code

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70550

            Bug ID: 70550
           Summary: -Wuninitialized false positives in OpenMP code
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jakub at gcc dot gnu.org
  Target Milestone: ---

#ifdef __SIZEOF_INT128__
typedef __int128 T;
#else
typedef long long T;
#endif

void bar (T);
#pragma omp declare target (bar)

void
foo (void)
{
  {
    int i;
    #pragma omp target defaultmap(tofrom:scalar)        /* { dg-bogus "is used
uninitialized in this function" } */
    {
      i = 26;
      bar (i);
    }
  }
  {
    T j;
    #pragma omp target defaultmap(tofrom:scalar)        /* { dg-bogus "is used
uninitialized in this function" } */
    {
      j = 37;
      bar (j);
    }
  }
  {
    int i;
    #pragma omp target                                  /* { dg-bogus "is used
uninitialized in this function" } */
    {
      i = 26;
      bar (i);
    }
  }
  {
    T j;
    #pragma omp target                                  /* { dg-bogus "is used
uninitialized in this function" } */
    {
      j = 37;
      bar (j);
    }
  }
  {
    int i;
    #pragma omp target firstprivate (i)                 /* { dg-warning "is
used uninitialized in this function" } */
    {
      i = 26;
      bar (i);
    }
  }
  {
    T j;
    #pragma omp target firstprivate (j)                 /* { dg-warning "is
used uninitialized in this function" } */
    {
      j = 37;
      bar (j);
    }
  }
  {
    int i;
    #pragma omp target private (i)                      /* { dg-bogus "is used
uninitialized in this function" } */
    {
      i = 26;
      bar (i);
    }
  }
  {
    T j;
    #pragma omp target private (j)                      /* { dg-bogus "is used
uninitialized in this function" } */
    {
      j = 37;
      bar (j);
    }
  }
}

shows some warnings that are IMNSHO desirable (explicit uses of firstprivate
clause with uninitialized var), and others where it is undesirable (mostly
implicit clauses).