[OPENMP] Codegen for 'reduction' clause in 'for' directive.

Emit a code for reduction clause. Next code should be emitted for reductions:

static kmp_critical_name lock = { 0 };

void reduce_func(void *lhs[<n>], void *rhs[<n>]) {
    *(Type0*)lhs[0] = ReductionOperation0(*(Type0*)lhs[0], *(Type0*)rhs[0]);
      ...
        *(Type<n>-1*)lhs[<n>-1] =
          ReductionOperation<n>-1(*(Type<n>-1*)lhs[<n>-1],
            *(Type<n>-1*)rhs[<n>-1]);
}

 ...
  void *RedList[<n>] = {&<RHSExprs>[0], ..., &<RHSExprs>[<n>-1]};
   switch (__kmpc_reduce{_nowait}(<loc>, <gtid>, <n>, sizeof(RedList), RedList, reduce_func, &<lock>)) {
      case 1:
        <LHSExprs>[0] = ReductionOperation0(*<LHSExprs>[0], *<RHSExprs>[0]);
          ...
            <LHSExprs>[<n>-1] = ReductionOperation<n>-1(*<LHSExprs>[<n>-1], *<RHSExprs>[<n>-1]);
             __kmpc_end_reduce{_nowait}(<loc>, <gtid>, &<lock>);
              break;
               case 2:
                 Atomic(<LHSExprs>[0] = ReductionOperation0(*<LHSExprs>[0], *<RHSExprs>[0]));
                   ...
                     Atomic(<LHSExprs>[<n>-1] = ReductionOperation<n>-1(*<LHSExprs>[<n>-1], *<RHSExprs>[<n>-1]));
                      break;
                       default:;
                        }
                        Reduction variables are a kind of a private variables, they have private copies, but initial values are chosen in accordance with the reduction operation.
Differential Revision: http://reviews.llvm.org/D9139

llvm-svn: 235506

1 files changed, 2 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGStmtOpenMP.cpp b/clang/lib/CodeGen/CGStmtOpenMP.cpp
index 744f9142db2..eb2647043b1 100644
--- a/clang/lib/CodeGen/CGStmtOpenMP.cpp
+++ b/clang/lib/CodeGen/CGStmtOpenMP.cpp
@@ -1078,6 +1078,7 @@ bool CodeGenFunction::EmitOMPWorksharingLoop(const OMPLoopDirective &S) {
       }
       EmitOMPPrivateClause(S, LoopScope);
       HasLastprivateClause = EmitOMPLastprivateClauseInit(S, LoopScope);
+      EmitOMPReductionClauseInit(S, LoopScope);
       EmitPrivateLoopCounters(*this, LoopScope, S.counters());
       (void)LoopScope.Privatize();
 
@@ -1126,6 +1127,7 @@ bool CodeGenFunction::EmitOMPWorksharingLoop(const OMPLoopDirective &S) {
                             UB.getAddress(), ST.getAddress(), IL.getAddress(),
                             Chunk);
       }
+      EmitOMPReductionClauseFinal(S);
       // Emit final copy of the lastprivate variables if IsLastIter != 0.
       if (HasLastprivateClause)
         EmitOMPLastprivateClauseFinal(