[turbofan] Loop peeling with explicit loop exits.

src/compiler/loop-analysis.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_LOOP_ANALYSIS_H_
 #define V8_COMPILER_LOOP_ANALYSIS_H_
 
 #include "src/base/iterator.h"
 #include "src/compiler/graph.h"
 #include "src/compiler/node.h"
@@ skipping 20 matching lines @@
         node_to_loop_num_(static_cast<int>(num_nodes), -1, zone),
         loop_nodes_(zone) {}
 
   // Represents a loop in the tree of loops, including the header nodes,
   // the body, and any nested loops.
   class Loop {
    public:
     Loop* parent() const { return parent_; }
     const ZoneVector<Loop*>& children() const { return children_; }
     size_t HeaderSize() const { return body_start_ - header_start_; }
-    size_t BodySize() const { return body_end_ - body_start_; }
-    size_t TotalSize() const { return body_end_ - header_start_; }
+    size_t BodySize() const { return exits_start_ - body_start_; }
+    size_t ExitsSize() const { return exits_end_ - exits_start_; }
+    size_t TotalSize() const { return exits_end_ - header_start_; }
     size_t depth() const { return static_cast<size_t>(depth_); }
 
    private:
     friend class LoopTree;
     friend class LoopFinderImpl;
 
     explicit Loop(Zone* zone)
         : parent_(nullptr),
           depth_(0),
           children_(zone),
           header_start_(-1),
           body_start_(-1),
-          body_end_(-1) {}
+          exits_start_(-1),
+          exits_end_(-1) {}
     Loop* parent_;
     int depth_;
     ZoneVector<Loop*> children_;
     int header_start_;
     int body_start_;
-    int body_end_;
+    int exits_start_;
+    int exits_end_;
   };
 
   // Return the innermost nested loop, if any, that contains {node}.
   Loop* ContainingLoop(Node* node) {
     if (node->id() >= node_to_loop_num_.size()) return nullptr;
     int num = node_to_loop_num_[node->id()];
     return num > 0 ? &all_loops_[num - 1] : nullptr;
   }
 
   // Check if the {loop} contains the {node}, either directly or by containing
@@ skipping 18 matching lines @@
     return NodeRange(&loop_nodes_[0] + loop->header_start_,
                      &loop_nodes_[0] + loop->body_start_);
   }
 
   // Return the header control node for a loop.
   Node* HeaderNode(Loop* loop);
 
   // Return a range which can iterate over the body nodes of {loop}.
   NodeRange BodyNodes(Loop* loop) {
     return NodeRange(&loop_nodes_[0] + loop->body_start_,
-                     &loop_nodes_[0] + loop->body_end_);
+                     &loop_nodes_[0] + loop->exits_start_);
+  }
+
+  // Return a range which can iterate over the body nodes of {loop}.
+  NodeRange ExitNodes(Loop* loop) {
+    return NodeRange(&loop_nodes_[0] + loop->exits_start_,
+                     &loop_nodes_[0] + loop->exits_end_);
   }
 
   // Return a range which can iterate over the nodes of {loop}.
   NodeRange LoopNodes(Loop* loop) {
     return NodeRange(&loop_nodes_[0] + loop->header_start_,
-                     &loop_nodes_[0] + loop->body_end_);
+                     &loop_nodes_[0] + loop->exits_end_);
   }
 
   // Return the node that represents the control, i.e. the loop node itself.
   Node* GetLoopControl(Loop* loop) {
     // TODO(turbofan): make the loop control node always first?
     for (Node* node : HeaderNodes(loop)) {
       if (node->opcode() == IrOpcode::kLoop) return node;
     }
     UNREACHABLE();
     return nullptr;
@@ skipping 32 matching lines @@
   // Build a loop tree for the entire graph.
   static LoopTree* BuildLoopTree(Graph* graph, Zone* temp_zone);
 };
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_LOOP_ANALYSIS_H_