[OPENMP]Target region: emit const firstprivates as globals with constant

memory.

If the variable with the constant non-scalar type is firstprivatized in
the target region, the local copy is created with the data copying.
Instead, we allocate the copy in the constant memory and avoid extra
copying in the outlined target regions. This global copy is used in the
target regions without loss of the performance.

llvm-svn: 355418

1 files changed, 13 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGStmtOpenMP.cpp b/clang/lib/CodeGen/CGStmtOpenMP.cpp
index 146525b8354..020f0b22483 100644
--- a/clang/lib/CodeGen/CGStmtOpenMP.cpp
+++ b/clang/lib/CodeGen/CGStmtOpenMP.cpp
@@ -725,6 +725,9 @@ bool CodeGenFunction::EmitOMPFirstprivateClause(const OMPExecutableDirective &D,
                                                 OMPPrivateScope &PrivateScope) {
   if (!HaveInsertPoint())
     return false;
+  bool DeviceConstTarget =
+      getLangOpts().OpenMPIsDevice &&
+      isOpenMPTargetExecutionDirective(D.getDirectiveKind());
   bool FirstprivateIsLastprivate = false;
   llvm::DenseSet<const VarDecl *> Lastprivates;
   for (const auto *C : D.getClausesOfKind<OMPLastprivateClause>()) {
@@ -754,6 +757,16 @@ bool CodeGenFunction::EmitOMPFirstprivateClause(const OMPExecutableDirective &D,
         ++InitsRef;
         continue;
       }
+      // Do not emit copy for firstprivate constant variables in target regions,
+      // captured by reference.
+      if (DeviceConstTarget && OrigVD->getType().isConstant(getContext()) &&
+          FD && FD->getType()->isReferenceType()) {
+        (void)CGM.getOpenMPRuntime().registerTargetFirstprivateCopy(*this,
+                                                                    OrigVD);
+        ++IRef;
+        ++InitsRef;
+        continue;
+      }
       FirstprivateIsLastprivate =
           FirstprivateIsLastprivate || ThisFirstprivateIsLastprivate;
       if (EmittedAsFirstprivate.insert(OrigVD->getCanonicalDecl()).second) {