source: CIVL/examples/omp/dataracebench-1.0.0/micro-benchmarks/indirectaccess1-orig-yes.c@ bd6628e

/*
Copyright (c) 2017, Lawrence Livermore National Security, LLC.
Produced at the Lawrence Livermore National Laboratory
Written by Chunhua Liao, Pei-Hung Lin, Joshua Asplund,
Markus Schordan, and Ian Karlin
(email: liao6@llnl.gov, lin32@llnl.gov, asplund1@llnl.gov,
schordan1@llnl.gov, karlin1@llnl.gov)
LLNL-CODE-732144
All rights reserved.

This file is part of DataRaceBench. For details, see
https://github.com/LLNL/dataracebench. Please also see the LICENSE file
for our additional BSD notice.

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or without modification, are permitted provided that the following
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* Redistributions of source code must retain the above copyright
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* Redistributions in binary form must reproduce the above copyright
  notice, this list of conditions and the disclaimer (as noted below)
  in the documentation and/or other materials provided with the
  distribution.

* Neither the name of the LLNS/LLNL nor the names of its contributors
  may be used to endorse or promote products derived from this
  software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
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*/


// two pointers have distance of 12
// index set has two indices with distance of 12: 999 +12 = 1011
// So there is loop carried dependence.
//
// However, having loop carried dependence does not mean data races.
// The iterations with loop carried dependence must be scheduled to 
// different threads. 
//
// In this example, we use schedule(static,1) to increase the chance that 
// the dependent loop iterations will be scheduled to different threads.
//
// Liao, 12/20/2016

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>

#define N 180
int indexSet[N] = {
521, 523, 525, 527, 529, 531,
547, 549, 551, 553, 555, 557,
573, 575, 577, 579, 581, 583,
599, 601, 603, 605, 607, 609,
625, 627, 629, 631, 633, 635,

651, 653, 655, 657, 659, 661,
859, 861, 863, 865, 867, 869,
885, 887, 889, 891, 893, 895,
911, 913, 915, 917, 919, 923, // change 921 to 923 = 911+12
937, 939, 941, 943, 945, 947,

963, 965, 967, 969, 971, 973,
989, 991, 993, 995, 997, 999, 
1197, 1199, 1201, 1203, 1205, 1207,
1223, 1225, 1227, 1229, 1231, 1233,
1249, 1251, 1253, 1255, 1257, 1259,

1275, 1277, 1279, 1281, 1283, 1285,
1301, 1303, 1305, 1307, 1309, 1311,
1327, 1329, 1331, 1333, 1335, 1337,
1535, 1537, 1539, 1541, 1543, 1545,
1561, 1563, 1565, 1567, 1569, 1571,

1587, 1589, 1591, 1593, 1595, 1597,
1613, 1615, 1617, 1619, 1621, 1623,
1639, 1641, 1643, 1645, 1647, 1649,
1665, 1667, 1669, 1671, 1673, 1675,
1873, 1875, 1877, 1879, 1881, 1883,

1899, 1901, 1903, 1905, 1907, 1909,
1925, 1927, 1929, 1931, 1933, 1935,
1951, 1953, 1955, 1957, 1959, 1961,
1977, 1979, 1981, 1983, 1985, 1987,
2003, 2005, 2007, 2009, 2011, 2013};

int main (int argc, char* argv[])
{
  double * base = (double*) malloc(sizeof(double)* (2013+12+1));

  if (base == 0)
  {
    printf ("Error in malloc(). Aborting ...\n");
    return 1;  
  }

  double * xa1 = base;
  double * xa3 = xa1 + 12;
  int i;

  // initialize segments touched by indexSet
  for (i =521; i<= 2025; ++i)
  {
    base[i]=0.5*i;
  }

#pragma omp parallel for schedule(static,1) // default static even scheduling may not trigger data race!
  for (i =0; i< N; ++i) 
  {
    int idx = indexSet[i];
    xa1[idx]+= 1.0 + i;
    xa3[idx]+= 3.0 + i;
  }

  printf("x1[999]=%f xa3[1285]=%f\n", xa1[999], xa3[1285]);
  free (base);
  return  0;
}