[OPENMP] Fixed codegen for 'omp cancel' construct.

If 'omp cancel' construct is used in a worksharing construct it may
cause hanging of the software in case if reduction clause is used. Patch fixes this problem by avoiding extra reduction processing for branches that were canceled.

llvm-svn: 287227

1 files changed, 24 insertions, 8 deletions

diff --git a/clang/lib/CodeGen/CGStmtOpenMP.cpp b/clang/lib/CodeGen/CGStmtOpenMP.cpp
index 937295e6600..2f5edc877ac 100644
--- a/clang/lib/CodeGen/CGStmtOpenMP.cpp
+++ b/clang/lib/CodeGen/CGStmtOpenMP.cpp
@@ -1781,9 +1781,11 @@ void CodeGenFunction::EmitOMPOuterLoop(bool DynamicOrOrdered, bool IsMonotonic,
   EmitBlock(LoopExit.getBlock());
 
   // Tell the runtime we are done.
-  if (!DynamicOrOrdered)
-    RT.emitForStaticFinish(*this, S.getLocEnd());
-
+  auto &&CodeGen = [DynamicOrOrdered, &S](CodeGenFunction &CGF) {
+    if (!DynamicOrOrdered)
+      CGF.CGM.getOpenMPRuntime().emitForStaticFinish(CGF, S.getLocEnd());
+  };
+  OMPCancelStack.emitExit(*this, S.getDirectiveKind(), CodeGen);
 }
 
 void CodeGenFunction::EmitOMPForOuterLoop(
@@ -1899,6 +1901,8 @@ void CodeGenFunction::EmitOMPDistributeParallelForDirective(
       *this, OMPD_distribute_parallel_for,
       [&S](CodeGenFunction &CGF, PrePostActionTy &) {
         OMPLoopScope PreInitScope(CGF, S);
+        OMPCancelStackRAII CancelRegion(CGF, OMPD_distribute_parallel_for,
+                                        /*HasCancel=*/false);
         CGF.EmitStmt(
             cast<CapturedStmt>(S.getAssociatedStmt())->getCapturedStmt());
       });
@@ -2123,7 +2127,10 @@ bool CodeGenFunction::EmitOMPWorksharingLoop(const OMPLoopDirective &S) {
                          [](CodeGenFunction &) {});
         EmitBlock(LoopExit.getBlock());
         // Tell the runtime we are done.
-        RT.emitForStaticFinish(*this, S.getLocStart());
+        auto &&CodeGen = [&S](CodeGenFunction &CGF) {
+          CGF.CGM.getOpenMPRuntime().emitForStaticFinish(CGF, S.getLocEnd());
+        };
+        OMPCancelStack.emitExit(*this, S.getDirectiveKind(), CodeGen);
       } else {
         const bool IsMonotonic =
             Ordered || ScheduleKind.Schedule == OMPC_SCHEDULE_static ||
@@ -2173,6 +2180,7 @@ void CodeGenFunction::EmitOMPForDirective(const OMPForDirective &S) {
   bool HasLastprivates = false;
   auto &&CodeGen = [&S, &HasLastprivates](CodeGenFunction &CGF,
                                           PrePostActionTy &) {
+    OMPCancelStackRAII CancelRegion(CGF, OMPD_for, S.hasCancel());
     HasLastprivates = CGF.EmitOMPWorksharingLoop(S);
   };
   {
@@ -2313,7 +2321,10 @@ void CodeGenFunction::EmitSections(const OMPExecutableDirective &S) {
     CGF.EmitOMPInnerLoop(S, /*RequiresCleanup=*/false, &Cond, &Inc, BodyGen,
                          [](CodeGenFunction &) {});
     // Tell the runtime we are done.
-    CGF.CGM.getOpenMPRuntime().emitForStaticFinish(CGF, S.getLocStart());
+    auto &&CodeGen = [&S](CodeGenFunction &CGF) {
+      CGF.CGM.getOpenMPRuntime().emitForStaticFinish(CGF, S.getLocEnd());
+    };
+    CGF.OMPCancelStack.emitExit(CGF, S.getDirectiveKind(), CodeGen);
     CGF.EmitOMPReductionClauseFinal(S);
     // Emit post-update of the reduction variables if IsLastIter != 0.
     emitPostUpdateForReductionClause(
@@ -2335,6 +2346,7 @@ void CodeGenFunction::EmitSections(const OMPExecutableDirective &S) {
     HasCancel = OSD->hasCancel();
   else if (auto *OPSD = dyn_cast<OMPParallelSectionsDirective>(&S))
     HasCancel = OPSD->hasCancel();
+  OMPCancelStackRAII CancelRegion(*this, S.getDirectiveKind(), HasCancel);
   CGM.getOpenMPRuntime().emitInlinedDirective(*this, OMPD_sections, CodeGen,
                                               HasCancel);
   // Emit barrier for lastprivates only if 'sections' directive has 'nowait'
@@ -2438,6 +2450,7 @@ void CodeGenFunction::EmitOMPParallelForDirective(
   // Emit directive as a combined directive that consists of two implicit
   // directives: 'parallel' with 'for' directive.
   auto &&CodeGen = [&S](CodeGenFunction &CGF, PrePostActionTy &) {
+    OMPCancelStackRAII CancelRegion(CGF, OMPD_parallel_for, S.hasCancel());
     CGF.EmitOMPWorksharingLoop(S);
   };
   emitCommonOMPParallelDirective(*this, S, OMPD_for, CodeGen);
@@ -3435,11 +3448,14 @@ void CodeGenFunction::EmitOMPCancelDirective(const OMPCancelDirective &S) {
 
 CodeGenFunction::JumpDest
 CodeGenFunction::getOMPCancelDestination(OpenMPDirectiveKind Kind) {
-  if (Kind == OMPD_parallel || Kind == OMPD_task)
+  if (Kind == OMPD_parallel || Kind == OMPD_task ||
+      Kind == OMPD_target_parallel)
     return ReturnBlock;
   assert(Kind == OMPD_for || Kind == OMPD_section || Kind == OMPD_sections ||
-         Kind == OMPD_parallel_sections || Kind == OMPD_parallel_for);
-  return BreakContinueStack.back().BreakBlock;
+         Kind == OMPD_parallel_sections || Kind == OMPD_parallel_for ||
+         Kind == OMPD_distribute_parallel_for ||
+         Kind == OMPD_target_parallel_for);
+  return OMPCancelStack.getExitBlock();
 }
 
 void CodeGenFunction::EmitOMPUseDevicePtrClause(