Commit 0c60ce13 authored by Tom Stellard's avatar Tom Stellard
Browse files

Merging r318848: 

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r318848 | hahnfeld | 2017-11-22 09:15:20 -0800 (Wed, 22 Nov 2017) | 7 lines

Fix for OMP doacross implementation on Power

Power has a weak consistency model so we need memory barriers to
make writes (both from runtime and from user code) available for
all threads.

Differential Revision: https://reviews.llvm.org/D40175
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llvm-svn: 319057
parent c510d367

openmp/runtime/src/kmp_csupport.cpp

+8 −1
Original line number Diff line number Diff line
@@ -3108,7 +3108,9 @@ void __kmpc_doacross_init(ident_t *loc, int gtid, int num_dims, 
  if (flags == NULL) {

    // we are the first thread, allocate the array of flags

    size_t size = trace_count / 8 + 8; // in bytes, use single bit per iteration

    sh_buf->doacross_flags = (kmp_uint32 *)__kmp_thread_calloc(th, size, 1);

    flags = (kmp_uint32 *)__kmp_thread_calloc(th, size, 1);

    KMP_MB();

    sh_buf->doacross_flags = flags;

  } else if (flags == (kmp_uint32 *)1) {

#if KMP_32_BIT_ARCH

    // initialization is still in progress, need to wait
@@ -3117,6 +3119,9 @@ void __kmpc_doacross_init(ident_t *loc, int gtid, int num_dims, 
    while (*(volatile kmp_int64 *)&sh_buf->doacross_flags == 1LL)

#endif

      KMP_YIELD(TRUE);

    KMP_MB();

  } else {

    KMP_MB();

  }

  KMP_DEBUG_ASSERT(sh_buf->doacross_flags > (kmp_uint32 *)1); // check ptr value

  pr_buf->th_doacross_flags =
@@ -3212,6 +3217,7 @@ void __kmpc_doacross_wait(ident_t *loc, int gtid, long long *vec) { 
  while ((flag & pr_buf->th_doacross_flags[iter_number]) == 0) {

    KMP_YIELD(TRUE);

  }

  KMP_MB();

  KA_TRACE(20,

           ("__kmpc_doacross_wait() exit: T#%d wait for iter %lld completed\n",

            gtid, (iter_number << 5) + shft));
@@ -3264,6 +3270,7 @@ void __kmpc_doacross_post(ident_t *loc, int gtid, long long *vec) { 
  shft = iter_number % 32; // use 32-bit granularity

  iter_number >>= 5; // divided by 32

  flag = 1 << shft;

  KMP_MB();

  if ((flag & pr_buf->th_doacross_flags[iter_number]) == 0)

    KMP_TEST_THEN_OR32(&pr_buf->th_doacross_flags[iter_number], flag);

  KA_TRACE(20, ("__kmpc_doacross_post() exit: T#%d iter %lld posted\n", gtid,

openmp/runtime/test/worksharing/for/kmp_doacross_check.c

+1 −1
Original line number Diff line number Diff line
@@ -24,7 +24,7 @@ int main() 
  dims.lo = 1;

  dims.up = N-1;

  dims.st = 1;

  #pragma omp parallel

  #pragma omp parallel num_threads(4)

  {

    int i, gtid;

    long long vec;