nvc/nvfortran -mp=gpu: compile succeeds but the kernel is missing at run time ("Failed to find device function") for function pointers, static locals, VLAs, long double, type-bound calls

// # Draft finding: omp52-c-w-vla-local on nvhpc
//
// - compiler: nvhpc
// - toolchain: nvhpc; arch: sm_80; machine: wingtip; memory mode: copy; opt: -O2
// - program: catalog omp52-c-w-vla-local (c, version 52, sha256 3eb9b9911edd8b3b)
// - expected: check=pass (trusted; elision + model)
// - actual: run_error  (exit_status: 1; without mandatory: exit_status: 1) [the confirmer's class run_error; the matrix's class of the same run is wrong_answer: a run that fails]
// - observed: no diagnostic; the run ends with "Accelerator Fatal Error: Failed to find device function 'nvkernel_main_...'" (25.11 and 26.9, both memory modes): a VLA declared in a target region
// - verdict: compiler_bug by rule R20-runtime-bug: a legal program fails at run time, deterministically, against an expected value from two or more independent sources with an executed witness, and another toolchain, mode, arch or the elision gives the expected value
// - reason: expected trusted check=pass (elision + model): stored main verdict: elision + model agree; witnesses: afar/gfx942/copy, cce20/gfx942/copy, cce21/gfx942/copy, elision
// - citations: RUL-DERIVED-NEEDS-EXECUTION (rulings.md); RUL-WITNESS-PER-MODE (rulings.md); RUL-SAME-COMPILER-RUNS (rulings.md); RUL-PRESENCE-WITNESS (rulings.md); RUL-METAMORPHIC-OTHER-FAMILY (rulings.md)
// - legality: legal: offload.engine.prerun.check accepts it (rerun: offload.engine.rules with the
//   race rule and the restriction checks, and the AFAR clang front end, not under test here); no
//   compiler under test, gfortran or gcc is a legality witness
// - witnesses: afar/gfx942/copy, cce20/gfx942/copy, cce21/gfx942/copy, elision
// - withdrawn: none
//
// Generated by compliance.widen (OpenMP 5.2, C11; catalog widening). Do not edit.
// id: omp52-c-w-vla-local
// primary atom: base.device.vla
// atoms: base.device.vla
// legal: yes
// observable: yes
// ran_on_host: inside the target region of interest
// evidence: construct
// needs: none
// std: c11
// feature: a variable-length array declared in a target region
// spec: OpenMP 5.2 §1.7, p.35: C11 is a normative base language
#include <stdio.h>
#include <stdbool.h>
#include <omp.h>

enum { n = 64 };

int main(void) {
  int a[n], b[n], ref[n];
  int host_flag = 1;
  int m = n;
  for (int i = 0; i < n; i++) {
    a[i] = i + 1;
    b[i] = 0;
    ref[i] = 2 * (i + 1) + 1;
  }
  #pragma omp target map(to: a, m) map(from: b) map(tofrom: host_flag)
  {
    host_flag = omp_is_initial_device();
    int t[m];
    for (int k = 0; k < m; k++) t[k] = 2 * a[k] + 1;
    for (int k = 0; k < m; k++) b[k] = t[k];
  }
  bool ok = true;
  for (int i = 0; i < n; i++)
    ok = ok && (b[i] == ref[i]);
  printf("RESULT ran_on_host=%d check=%s\n", host_flag, ok ? "pass" : "fail");
  return 0;
}