[OPENMP] Add restriction for reduction clause in taskloop directives.

Added checks for the reduction clauses in the taskloop directives:
1. Only addressable items must be used in reduction clauses.
2. Reduction clauses cannot be used with nogroup clauses.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@307693 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Basic/DiagnosticSemaKinds.td

@@ -8860,6 +8860,10 @@ def warn_omp_nesting_simd : Warning<
 def err_omp_orphaned_device_directive : Error<
   "orphaned 'omp %0' directives are prohibited"
   "; perhaps you forget to enclose the directive into a %select{|||target |teams }1region?">;
+def err_omp_reduction_non_addressable_expression : Error<
+  "expected addressable reduction item for the task-based directives">;
+def err_omp_reduction_with_nogroup : Error<
+  "'reduction' clause cannot be used with 'nogroup' clause">;
 } // end of OpenMP category
 
 let CategoryName = "Related Result Type Issue" in {

lib/Sema/SemaOpenMP.cpp

@@ -6106,6 +6106,33 @@ static bool checkGrainsizeNumTasksClauses(Sema &S,
   return ErrorFound;
 }
 
+static bool checkReductionClauseWithNogroup(Sema &S,
+                                            ArrayRef<OMPClause *> Clauses) {
+  OMPClause *ReductionClause = nullptr;
+  OMPClause *NogroupClause = nullptr;
+  for (auto *C : Clauses) {
+    if (C->getClauseKind() == OMPC_reduction) {
+      ReductionClause = C;
+      if (NogroupClause)
+        break;
+      continue;
+    }
+    if (C->getClauseKind() == OMPC_nogroup) {
+      NogroupClause = C;
+      if (ReductionClause)
+        break;
+      continue;
+    }
+  }
+  if (ReductionClause && NogroupClause) {
+    S.Diag(ReductionClause->getLocStart(), diag::err_omp_reduction_with_nogroup)
+        << SourceRange(NogroupClause->getLocStart(),
+                       NogroupClause->getLocEnd());
+    return true;
+  }
+  return false;
+}
+
 StmtResult Sema::ActOnOpenMPTaskLoopDirective(
     ArrayRef<OMPClause *> Clauses, Stmt *AStmt, SourceLocation StartLoc,
     SourceLocation EndLoc,
@@ -6132,6 +6159,11 @@ StmtResult Sema::ActOnOpenMPTaskLoopDirective(
   // not appear on the same taskloop directive.
   if (checkGrainsizeNumTasksClauses(*this, Clauses))
     return StmtError();
+  // OpenMP, [2.9.2 taskloop Construct, Restrictions]
+  // If a reduction clause is present on the taskloop directive, the nogroup
+  // clause must not be specified.
+  if (checkReductionClauseWithNogroup(*this, Clauses))
+    return StmtError();
 
   getCurFunction()->setHasBranchProtectedScope();
   return OMPTaskLoopDirective::Create(Context, StartLoc, EndLoc,
@@ -6175,6 +6207,11 @@ StmtResult Sema::ActOnOpenMPTaskLoopSimdDirective(
   // not appear on the same taskloop directive.
   if (checkGrainsizeNumTasksClauses(*this, Clauses))
     return StmtError();
+  // OpenMP, [2.9.2 taskloop Construct, Restrictions]
+  // If a reduction clause is present on the taskloop directive, the nogroup
+  // clause must not be specified.
+  if (checkReductionClauseWithNogroup(*this, Clauses))
+    return StmtError();
 
   getCurFunction()->setHasBranchProtectedScope();
   return OMPTaskLoopSimdDirective::Create(Context, StartLoc, EndLoc,
@@ -9399,6 +9436,12 @@ OMPClause *Sema::ActOnOpenMPReductionClause(
                          SimpleRefExpr, RefRes.get());
           if (!PostUpdateRes.isUsable())
             continue;
+          if (isOpenMPTaskingDirective(DSAStack->getCurrentDirective())) {
+            Diag(RefExpr->getExprLoc(),
+                 diag::err_omp_reduction_non_addressable_expression)
+                << RefExpr->getSourceRange();
+            continue;
+          }
           ExprPostUpdates.push_back(
               IgnoredValueConversions(PostUpdateRes.get()).get());
         }

test/OpenMP/taskloop_ast_print.cpp

@@ -20,7 +20,7 @@ T tmain(T argc) {
 // CHECK-NEXT: for (int i = 0; i < 2; ++i)
 // CHECK-NEXT: a = 2;
 #pragma omp parallel
-#pragma omp taskloop private(argc, b), firstprivate(c, d), lastprivate(d, f) collapse(N) shared(g) if (c) final(d) mergeable priority(f) nogroup num_tasks(N) reduction(min:a)
+#pragma omp taskloop private(argc, b), firstprivate(c, d), lastprivate(d, f) collapse(N) shared(g) if (c) final(d) mergeable priority(f) nogroup num_tasks(N)
   for (int i = 0; i < 2; ++i)
     for (int j = 0; j < 2; ++j)
       for (int j = 0; j < 2; ++j)
@@ -33,7 +33,7 @@ T tmain(T argc) {
           for (int j = 0; j < 2; ++j)
             foo();
   // CHECK-NEXT: #pragma omp parallel
-  // CHECK-NEXT: #pragma omp taskloop private(argc,b) firstprivate(c,d) lastprivate(d,f) collapse(N) shared(g) if(c) final(d) mergeable priority(f) nogroup num_tasks(N) reduction(min: a)
+  // CHECK-NEXT: #pragma omp taskloop private(argc,b) firstprivate(c,d) lastprivate(d,f) collapse(N) shared(g) if(c) final(d) mergeable priority(f) nogroup num_tasks(N)
   // CHECK-NEXT: for (int i = 0; i < 2; ++i)
   // CHECK-NEXT: for (int j = 0; j < 2; ++j)
   // CHECK-NEXT: for (int j = 0; j < 2; ++j)
@@ -53,8 +53,8 @@ int main(int argc, char **argv) {
   int b = argc, c, d, e, f, g;
   static int a;
 // CHECK: static int a;
-#pragma omp taskloop if(taskloop: a) default(none) shared(a) final(b) priority(5) nogroup num_tasks(argc) reduction(*: g)
-  // CHECK-NEXT: #pragma omp taskloop if(taskloop: a) default(none) shared(a) final(b) priority(5) nogroup num_tasks(argc) reduction(*: g)
+#pragma omp taskloop if(taskloop: a) default(none) shared(a) final(b) priority(5) num_tasks(argc) reduction(*: g)
+  // CHECK-NEXT: #pragma omp taskloop if(taskloop: a) default(none) shared(a) final(b) priority(5) num_tasks(argc) reduction(*: g)
   for (int i = 0; i < 2; ++i)
     a = 2;
 // CHECK-NEXT: for (int i = 0; i < 2; ++i)