parallel-reduction.c

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/*
 * parallel-reduction.c -- Archer testcase
 */
 
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
//
// See tools/archer/LICENSE.txt for details.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
 
 
// RUN: %libarcher-compile-and-run| FileCheck %s
// REQUIRES: tsan
#include <omp.h>
#include <stdio.h>
 
int main(int argc, char *argv[]) {
  int var = 0;
 
// Number of threads is empirical: We need enough threads so that
// the reduction is really performed hierarchically in the barrier!
#pragma omp parallel num_threads(5) reduction(+ : var)
  { var = 1; }
 
  fprintf(stderr, "DONE\n");
  int error = (var != 5);
  return error;
}
 
// CHECK-NOT: ThreadSanitizer: data race
// CHECK-NOT: ThreadSanitizer: reported
// CHECK: DONE