[turbofan] Introduce BranchMatcher and DiamondMatcher helpers.

src/compiler/node-matchers.h

 // Copyright 2014 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_NODE_MATCHERS_H_
 #define V8_COMPILER_NODE_MATCHERS_H_
 
 #include <cmath>
 
 // TODO(turbofan): Move ExternalReference out of assembler.h
@@ skipping 524 matching lines @@
     scale_ = scale;
     matches_ = true;
   }
 };
 
 typedef BaseWithIndexAndDisplacementMatcher<Int32AddMatcher>
     BaseWithIndexAndDisplacement32Matcher;
 typedef BaseWithIndexAndDisplacementMatcher<Int64AddMatcher>
     BaseWithIndexAndDisplacement64Matcher;
 
+struct BranchMatcher : public NodeMatcher {
+  explicit BranchMatcher(Node* branch);
+
+  bool Matched() const { return if_true_ && if_false_; }
+
+  Node* Branch() const { return node(); }
+  Node* IfTrue() const { return if_true_; }
+  Node* IfFalse() const { return if_false_; }
+
+ private:
+  Node* if_true_;
+  Node* if_false_;
+};
+
+
+struct DiamondMatcher : public NodeMatcher {
+  explicit DiamondMatcher(Node* merge);
+
+  bool Matched() const { return branch_; }
+  bool IfProjectionsAreOwned() const {
+    return if_true_->OwnedBy(node()) && if_false_->OwnedBy(node());
+  }
+
+  Node* Branch() const { return branch_; }
+  Node* IfTrue() const { return if_true_; }
+  Node* IfFalse() const { return if_false_; }
+  Node* Merge() const { return node(); }
+
+ private:
+  Node* branch_;
+  Node* if_true_;
+  Node* if_false_;
+};
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_NODE_MATCHERS_H_