[turbofan] Greedy: smarter last resort splitting.

src/compiler/greedy-allocator.h

 // 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_GREEDY_ALLOCATOR_H_
 #define V8_GREEDY_ALLOCATOR_H_
 
 #include "src/compiler/coalesced-live-ranges.h"
 #include "src/compiler/register-allocator.h"
 #include "src/zone-containers.h"
@@ skipping 167 matching lines @@
   //   call" portion.
   // - the portion after the call.
   LiveRange* GetRemainderAfterSplittingAroundFirstCall(LiveRange* range);
 
   // While we attempt to merge spill ranges later on in the allocation pipeline,
   // we want to ensure group elements get merged. Waiting until later may hinder
   // merge-ability, since the pipeline merger (being naive) may create conflicts
   // between spill ranges of group members.
   void TryReuseSpillRangesForGroups();
 
+  LifetimePosition GetLastResortSplitPosition(const LiveRange* range);
+
+  bool IsProgressPossible(const LiveRange* range);
+
   // Necessary heuristic: spill when all else failed.
   void SpillRangeAsLastResort(LiveRange* range);
 
   void AssignRangeToRegister(int reg_id, LiveRange* range);
 
   Zone* local_zone_;
   ZoneVector<CoalescedLiveRanges*> allocations_;
   AllocationScheduler scheduler_;
   ZoneVector<LiveRangeGroup*> groups_;
 
   DISALLOW_COPY_AND_ASSIGN(GreedyAllocator);
 };
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 #endif  // V8_GREEDY_ALLOCATOR_H_