[Bug fortran/93553] ICE in scan_omp_1_op, at omp-low.c:3485

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93553

Tobias Burnus <burnus at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |burnus at gcc dot gnu.org

--- Comment #6 from Tobias Burnus <burnus at gcc dot gnu.org> ---
Slightly simplified one can use a scalar 'c' instead of an array. One gets
(-fdump-tree-gimple):

  #pragma omp parallel reduction(+:x) shared(c)
    {
      integer(kind=8) D.3933;
      integer(kind=8) D.3934;

      #pragma omp for nowait private(i)
      for (i = 1; i <= 8; i = i + 1)
          {
            D.3933 = (integer(kind=8)) i;
            D.3934 = D.3933 + -1;
            (*x)[D.3934] = c;

During omp-lowering, one has:
…
D.3924 = S.0 + -1;
D.3940 = x;
(*D.3940)[D.3924] = 0;

The "D.3940 = x;" is processed and the "D.3940" ends up as "tp" argument to
"scan_omp_1_op" which calls then in turn:
  tree repl = remap_decl (t, &ctx->cb)
The latter then calls
  omp_copy_decl
and returns error_mark_node → this gives then the gcc_assert in scan_omp1_op.

By contrast, "S.0" appears in ctx->cb->decl_map and, hence, omp_copy_decl is
not called for it.