[OPENMP50]Add codegen for acq_rel clause in atomic|flush directives.

Added codegen support for atomic|flush directives with acq_rel clause.
diff --git a/clang/lib/CodeGen/CGOpenMPRuntime.cpp b/clang/lib/CodeGen/CGOpenMPRuntime.cpp
index 3ed4285..23d49b2 100644
--- a/clang/lib/CodeGen/CGOpenMPRuntime.cpp
+++ b/clang/lib/CodeGen/CGOpenMPRuntime.cpp
@@ -3875,7 +3875,7 @@
 }
 
 void CGOpenMPRuntime::emitFlush(CodeGenFunction &CGF, ArrayRef<const Expr *>,
-                                SourceLocation Loc) {
+                                SourceLocation Loc, llvm::AtomicOrdering AO) {
   llvm::OpenMPIRBuilder *OMPBuilder = CGF.CGM.getOpenMPIRBuilder();
   if (OMPBuilder) {
     OMPBuilder->CreateFlush(CGF.Builder);
@@ -11943,7 +11943,8 @@
 
 void CGOpenMPSIMDRuntime::emitFlush(CodeGenFunction &CGF,
                                     ArrayRef<const Expr *> Vars,
-                                    SourceLocation Loc) {
+                                    SourceLocation Loc,
+                                    llvm::AtomicOrdering AO) {
   llvm_unreachable("Not supported in SIMD-only mode");
 }