[turbofan] fine grained in-block move optimization

src/compiler/move-optimizer.h

Index: src/compiler/move-optimizer.h
diff --git a/src/compiler/move-optimizer.h b/src/compiler/move-optimizer.h
index c9a3289d6b26ab625f6b13bc4525d857358c3082..8e932a0d730e78378a23456bdb184bdf10b61840 100644
--- a/src/compiler/move-optimizer.h
+++ b/src/compiler/move-optimizer.h
@@ -26,15 +26,30 @@ class MoveOptimizer final {
   Zone* code_zone() const { return code()->zone(); }
   MoveOpVector& local_vector() { return local_vector_; }
 
-  void CompressBlock(InstructionBlock* blocke);
-  void CompressMoves(ParallelMove* left, ParallelMove* right);
+  // Consolidate moves into the first gap.
+  void CompressGaps(Instruction* instr);
+
+  // Attempt to push down to the last instruction those moves that can.

[Jarin, 2016/02/03 05:25:18]

Could not parse the comment. Please, rewrite.

(Does it mean "Push the moves in {block} as late as possible."?

+  void CompressBlock(InstructionBlock* block);
+
+  // Consolidate moves into the first gap.
+  void CompressMoves(ParallelMove* left, MoveOpVector* right);
+
+  // Push down those moves in the gap of from that do not change the
+  // semantics of the from instruction, nor the semantics of the moves
+  // that remain behind.

[Jarin, 2016/02/03 05:25:18]

Again, could not really parse that comment.

+  void MigrateMoves(Instruction* to, Instruction* from);
+
+  void RemoveClobberedDestinations(Instruction* instruction);
+
   const Instruction* LastInstruction(const InstructionBlock* block) const;
+
+  // Consolidate common moves appearing accross all predecessors of a block.
   void OptimizeMerge(InstructionBlock* block);
   void FinalizeMoves(Instruction* instr);
 
   Zone* const local_zone_;
   InstructionSequence* const code_;
-  Instructions to_finalize_;
   MoveOpVector local_vector_;
 
   DISALLOW_COPY_AND_ASSIGN(MoveOptimizer);