OpenACC: a declare link variable used in a routine is rejected (C)

// # Finding (GCC 16.2): a declare link variable used in an OpenACC routine is rejected (C); the reproducer is the catalog program
//   acc34-c-clause-link
//
// - toolchains: gcc_g90 (GCC 16.2.0, AMD Instinct MI250X gfx90a, Tioga) and gcc_sm80 (GCC 16.2.0,
//   NVIDIA A100 sm_80, wingtip); separate memory only; -O2; OMP_TARGET_OFFLOAD=mandatory
// - build: gcc -fopenacc -foffload=amdgcn-amdhsa -foffload-options=amdgcn-amdhsa=-march=gfx90a -O2 (gcc_g90); -foffload=nvptx-none
//   -foffload-options=nvptx-none=-march=sm_80 -foffload-options=nvptx-none=-latomic -O2 (gcc_sm80)
// - failure: rejected: with .link. clause used in .routine. function
// - observed: `error: 'lv' with 'link' clause used in 'routine' function` on both GPUs.
// - expected: compiles; `RESULT ran_on_host=0 check=pass`
// - spec: "The global variable or common block variables may be used in accelerator routines" (OpenACC 3.4 §2.13.3 l.3083-3084),
//   for a variable in a declare link clause; the device copy exists while a data clause holds it (l.3079-3081), here the parallel
//   loop's copyin(lv).
// - GCC 16.2 documentation (libgomp.texi "Enabling OpenACC"): "A complete description of all OpenACC directives accepted may be
//   found in the OpenACC Application Programming Interface manual, version 2.6"; _OPENACC is 201711 (2.6). No list of OpenACC gaps
//   is documented.
// - other families: NVHPC 25.11/26.9 compile it and give a wrong answer (not studied here).
// - gate and confirmer: 2 cells (1 gcc_g90, 1 gcc_sm80), each confirmed in the gate's four environments (a-d;
//   results/gcc/gate-tioga/ and gate-wingtip/ verdicts.jsonl); confirmer verdicts (results/gcc/confirm/batch.gcc_*.jsonl):
//   compiler_bug (R11-compile-rejection) 2
// - catalog programs (1): acc34-c-clause-link
// - legality: the catalog programs are legal by construction (offload.engine.gen, c_gen and acc_gen
//   check every program against the catalog rules and the offload scope as it is built; no
//   compiler). GCC is a compiler under test only: never a legality witness, here or for another
//   family's case (catalog/machines.yaml under_test_only).
// Generated by compliance.acc_c_gen (OpenACC 3.4, C11): the C port (offload.engine.f2c) of acc34-clause-link. Do not edit.
// id: acc34-c-clause-link
// primary atom: acc.clause.link
// legal: yes
// observable: yes
// ran_on_host: inside the compute region of interest (acc_on_device)
// evidence: construct
// needs: none
// std: c11
#include <stdio.h>
#include <stdbool.h>
#include <openacc.h>

enum { n = 64 };
int lv[64];
#pragma acc declare link(lv)
#pragma acc routine seq
int get_lv(int k) {
  int r_;
  r_ = lv[k - 1];
  return r_;
}

int main(void) {
  int a[n];
  int b[n];
  int ref[n];
  int host_flag;
  bool ok;
  for (int i = 1; i <= n; i++) {
    a[i - 1] = i;
    b[i - 1] = 0;
    ref[i - 1] = 2 * i + 1;
  }
  host_flag = 1;
  for (int i = 1; i <= n; i++) {
    lv[i - 1] = 2 * i + 1;
  }
  #pragma acc parallel loop copyin(a) copyout(b) copy(host_flag) copyin(lv)
  for (int i = 1; i <= n; i++) {
    if (i == 1) host_flag = (acc_on_device(acc_device_host) ? 1 : 0);
    b[i - 1] = get_lv(a[i - 1]);
  }
  bool t1_ = true;
  for (int k2_ = 0; k2_ < n; k2_++)
    t1_ = t1_ && (b[k2_] == ref[k2_]);
  ok = t1_;
  printf("RESULT ran_on_host=%d check=%s\n", host_flag, ok ? "pass" : "fail");
  return 0;
}