[OPENMP]Add call to __kmpc_push_target_tripcount() function.

Each we create the target regions with the teams distribute inner
region, we can better estimate number of the teams required to execute
the target region. Function __kmpc_push_target_tripcount() is used for
purpose, which accepts device_id and the number of the iterations,
performed by the associated loop.

llvm-svn: 350571
diff --git a/clang/lib/CodeGen/CGOpenMPRuntime.h b/clang/lib/CodeGen/CGOpenMPRuntime.h
index d9ac5df..933c8af 100644
--- a/clang/lib/CodeGen/CGOpenMPRuntime.h
+++ b/clang/lib/CodeGen/CGOpenMPRuntime.h
@@ -1367,6 +1367,15 @@
                                           bool IsOffloadEntry,
                                           const RegionCodeGenTy &CodeGen);
 
+  /// Emit code that pushes the trip count of loops associated with constructs
+  /// 'target teams distribute' and 'teams distribute parallel for'.
+  /// \param SizeEmitter Emits the int64 value for the number of iterations of
+  /// the associated loop.
+  virtual void emitTargetNumIterationsCall(
+      CodeGenFunction &CGF, const OMPExecutableDirective &D, const Expr *Device,
+      const llvm::function_ref<llvm::Value *(
+          CodeGenFunction &CGF, const OMPLoopDirective &D)> &SizeEmitter);
+
   /// Emit the target offloading code associated with \a D. The emitted
   /// code attempts offloading the execution to the device, an the event of
   /// a failure it executes the host version outlined in \a OutlinedFn.