Reland: Introducing the LLVM greedy register allocator.

src/zone-containers.h

Index: src/zone-containers.h
diff --git a/src/zone-containers.h b/src/zone-containers.h
index 0a599bcf2b0501500fc4a17369728a7660cc8107..fc57c04adc56a394241e93380aca9de7cccf328a 100644
--- a/src/zone-containers.h
+++ b/src/zone-containers.h
@@ -63,6 +63,17 @@ class ZoneLinkedList : public std::list<T, zone_allocator<T>> {
 };
 
 
+// A wrapper subclass std::priority_queue to make it easy to construct one
+// that uses a zone allocator.
+template <typename T, typename Compare = std::less<T>>
+class ZonePriorityQueue : public std::priority_queue<T, ZoneVector<T>> {
+ public:
+  // Constructs an empty list.
+  explicit ZonePriorityQueue(Zone* zone)
+      : std::priority_queue<T, ZoneVector<T>>(Compare(), ZoneVector<T>(zone)) {}
+};
+
+
 // A wrapper subclass for std::queue to make it easy to construct one
 // that uses a zone allocator.
 template <typename T>