[turbofan] Introduce BranchMatcher and DiamondMatcher helpers.

src/compiler/node-matchers.h

Index: src/compiler/node-matchers.h
diff --git a/src/compiler/node-matchers.h b/src/compiler/node-matchers.h
index 1cdb6547f4e7d831c616d8ec5c337d64a25c7449..e0c90051cc47604a54a60566c48870b95797c1d8 100644
--- a/src/compiler/node-matchers.h
+++ b/src/compiler/node-matchers.h
@@ -542,6 +542,40 @@ typedef BaseWithIndexAndDisplacementMatcher<Int32AddMatcher>
 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 IfProjsAreOwned() const {

[Benedikt Meurer, 2015/04/07 07:19:01]

Nit: Please rename to ProjectionsAreOwned() or IsPureDiamond() or something like
that.

[titzer, 2015/04/07 08:41:00]

Done.

+    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