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    <head>
      <base href="https://bugs.llvm.org/">
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - Undefined symbol when -polly-parallel is enabled"
   href="https://bugs.llvm.org/show_bug.cgi?id=38493">38493</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Undefined symbol when -polly-parallel is enabled
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>libraries
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>trunk
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>PC
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Windows NT
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>enhancement
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>Support Libraries
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>unassignedbugs@nondot.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>m-takahiro@jp.fujitsu.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>When automatic parallelization using polly is applied, a linker outputs an
error:  undefined symbol: GOMP_*.

-------- test.c --------
#include <stdio.h>
#include <math.h>

#define N 300
#define M 4
double a[N][M];
double b[N][M];
double c[N][M];

void foo(int m) {
  int i,j;
  for (j=0; j<N; ++j) {
    for (i=0; i<m; ++i) {
      a[j][i] += b[j][i]*c[j][i];
    }
  }
}

double suma(void) {
  int i,j;
  double s;
  s = 0.0;
  for (j=0; j<N; ++j) {
    for (i=0; i<M; ++i) {
      s += a[j][i];
    }
  }
  return s;
}

#define ANS  (double)300.0000
#define GOSA (double)0.0

int main(void) {
  int i,j;
  double s;
  for (j=0; j<N; ++j) {
    for (i=0; i<M; ++i) {
      a[j][i] = 0.0;
      b[j][i] = 0.5;
      c[j][i] = 0.5;
    }
  }
  foo(M);
  s = suma();
  if (fabs(s - ANS) <= GOSA) {
    printf("ok\n");
  } else {
    printf("ng: %lf != %lf\n", s, ANS);
  }
}
---------------------

$ clang --version
clang version 8.0.0 (trunk 339303)
Target: x86_64-unknown-linux-gnu

$ clang -O3 -mllvm -polly -mllvm -polly-parallel test.c
ld: error: undefined symbol: GOMP_parallel_loop_runtime_start
<span class="quote">>>> referenced by 3-P-275_01.c
>>>               /home/takahiro/tmp/3-P-275_01-0c2466.o:(foo)</span >

ld: error: undefined symbol: GOMP_parallel_end
<span class="quote">>>> referenced by 3-P-275_01.c
>>>               /home/takahiro/tmp/3-P-275_01-0c2466.o:(foo)</span >

ld: error: undefined symbol: GOMP_loop_runtime_next
<span class="quote">>>> referenced by 3-P-275_01.c
>>>               /home/takahiro/tmp/3-P-275_01-0c2466.o:(foo_polly_subfn)</span >

ld: error: undefined symbol: GOMP_loop_runtime_next
<span class="quote">>>> referenced by 3-P-275_01.c
>>>               /home/takahiro/tmp/3-P-275_01-0c2466.o:(foo_polly_subfn)</span >

ld: error: undefined symbol: GOMP_loop_end_nowait
<span class="quote">>>> referenced by 3-P-275_01.c
>>>               /home/takahiro/tmp/3-P-275_01-0c2466.o:(foo_polly_subfn)</span >


But, If I added -fopenmp option to the above options, the linker didn't output
the error and compilation succeeded. So, when -polly-parallel option is
specified, should I need to specify -fopenmp option? Or, should clang pass
"-lomp" to the linker implicitly?</pre>
        </div>
      </p>


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