[turbofan] Preprocessing live ranges before register allocation.

src/compiler/preprocess-live-ranges.h

Index: src/compiler/preprocess-live-ranges.h
diff --git a/src/compiler/preprocess-live-ranges.h b/src/compiler/preprocess-live-ranges.h
new file mode 100644
index 0000000000000000000000000000000000000000..aa852fc7ca40606959596efd900ab67fbad234c0
--- /dev/null
+++ b/src/compiler/preprocess-live-ranges.h
@@ -0,0 +1,35 @@
+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_PREPROCESS_LIVE_RANGES_H_
+#define V8_PREPROCESS_LIVE_RANGES_H_
+
+#include "src/compiler/register-allocator.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+
+class PreprocessLiveRanges final {
+ public:
+  PreprocessLiveRanges(RegisterAllocationData* data, Zone* zone)
+      : data_(data), zone_(zone) {}
+  void PreprocessRanges();
+
+ private:
+  void SplitRangesAroundDeferredBlocks();
+
+  RegisterAllocationData* data() { return data_; }
+  Zone* zone() { return zone_; }
+
+  RegisterAllocationData* data_;
+  Zone* zone_;
+};
+
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8
+#endif  // V8_PREPROCESS_LIVE_RANGES_H_