[turbofan] Support for combining branches with <Operation>WithOverflow.

src/compiler/node.cc

 // 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.
 
 #include "src/compiler/node.h"
 
 #include "src/compiler/generic-node-inl.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 void Node::CollectProjections(int projection_count, Node** projections) {
   for (int i = 0; i < projection_count; ++i) projections[i] = NULL;
   for (UseIter i = uses().begin(); i != uses().end(); ++i) {
     if ((*i)->opcode() != IrOpcode::kProjection) continue;
     int32_t index = OpParameter<int32_t>(*i);
     ASSERT_GE(index, 0);
     ASSERT_LT(index, projection_count);
     ASSERT_EQ(NULL, projections[index]);
     projections[index] = *i;
   }
 }
 
 
+Node* Node::FindProjection(int32_t projection_index) {
+  for (UseIter i = uses().begin(); i != uses().end(); ++i) {
+    if ((*i)->opcode() == IrOpcode::kProjection &&
+        OpParameter<int32_t>(*i) == projection_index) {
+      return *i;
+    }
+  }
+  return NULL;
+}
+
+
 OStream& operator<<(OStream& os, const Operator& op) { return op.PrintTo(os); }
 
 
 OStream& operator<<(OStream& os, const Node& n) {
   os << n.id() << ": " << *n.op();
   if (n.op()->InputCount() != 0) {
     os << "(";
     for (int i = 0; i < n.op()->InputCount(); ++i) {
       if (i != 0) os << ", ";
       os << n.InputAt(i)->id();
     }
     os << ")";
   }
   return os;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8