[turbofan] Move GetCommonDominator to BasicBlock.

src/compiler/schedule.h

 // Copyright 2013 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_COMPILER_SCHEDULE_H_
 #define V8_COMPILER_SCHEDULE_H_
 
 #include <iosfwd>
 
 #include "src/zone-containers.h"
@@ skipping 147 matching lines @@
   void set_loop_number(int32_t loop_number) { loop_number_ = loop_number; }
 
   RpoNumber GetRpoNumber() const { return RpoNumber::FromInt(rpo_number_); }
   int32_t rpo_number() const { return rpo_number_; }
   void set_rpo_number(int32_t rpo_number);
 
   // Loop membership helpers.
   inline bool IsLoopHeader() const { return loop_end_ != NULL; }
   bool LoopContains(BasicBlock* block) const;
 
+  // Computes the immediate common dominator of {b1} and {b2}. The worst time
+  // complexity is O(N) where N is the height of the dominator tree.
+  static BasicBlock* GetCommonDominator(BasicBlock* b1, BasicBlock* b2);
+
  private:
   int32_t loop_number_;      // loop number of the block.
   int32_t rpo_number_;       // special RPO number of the block.
   bool deferred_;            // true if the block contains deferred code.
   int32_t dominator_depth_;  // Depth within the dominator tree.
   BasicBlock* dominator_;    // Immediate dominator of the block.
   BasicBlock* rpo_next_;     // Link to next block in special RPO order.
   BasicBlock* loop_header_;  // Pointer to dominating loop header basic block,
                              // NULL if none. For loop headers, this points to
                              // enclosing loop header.
@@ skipping 96 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(Schedule);
 };
 
 std::ostream& operator<<(std::ostream&, const Schedule&);
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_SCHEDULE_H_