[turbofan] Transfer types from loop phis to OSR values.

src/compiler/osr.cc

 // 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.
 
 #include "src/compiler.h"
 #include "src/compiler/all-nodes.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/control-reducer.h"
 #include "src/compiler/frame.h"
 #include "src/compiler/graph.h"
@@ skipping 156 matching lines @@
   end->ReplaceInput(0, merge);
 
   if (FLAG_trace_turbo_graph) {  // Simple textual RPO.
     OFStream os(stdout);
     os << "-- Graph after OSR duplication -- " << std::endl;
     os << AsRPO(*graph);
   }
 }
 
 
+static void TransferOsrValueTypesFromLoopPhis(Zone* zone, Node* osr_loop_entry,
+                                              Node* osr_loop) {
+  // Find the index of the osr loop entry into the loop.
+  int index = 0;
+  for (index = 0; index < osr_loop->InputCount(); index++) {
+    if (osr_loop->InputAt(index) == osr_loop_entry) break;
+  }
+  if (index == osr_loop->InputCount()) return;
+
+  for (Node* osr_value : osr_loop_entry->uses()) {
+    if (osr_value->opcode() != IrOpcode::kOsrValue) continue;
+    bool unknown = true;
+    for (Node* phi : osr_value->uses()) {
+      if (phi->opcode() != IrOpcode::kPhi) continue;
+      if (NodeProperties::GetControlInput(phi) != osr_loop) continue;
+      if (phi->InputAt(index) != osr_value) continue;
+      if (NodeProperties::IsTyped(phi)) {
+        // Transfer the type from the phi to the OSR value itself.
+        Bounds phi_bounds = NodeProperties::GetBounds(phi);
+        if (NodeProperties::IsTyped(osr_value)) {
+          Bounds osr_bounds = NodeProperties::GetBounds(osr_value);
+          NodeProperties::SetBounds(osr_value,
+                                    Bounds::Both(phi_bounds, osr_bounds, zone));
+        } else {
+          NodeProperties::SetBounds(osr_value, phi_bounds);
+        }
+        unknown = false;
+      }
+    }
+    if (unknown) NodeProperties::SetBounds(osr_value, Bounds::Unbounded(zone));

[Benedikt Meurer, 2015/02/18 09:18:10]

I'd suggest to use

 NodeProperties::SetBounds(osr_value, Bounds::Unbounded(zone));

as default before the loop instead of having that unknown variable. Then you
don't need the !NodeProperties::IsTyped(osr_value) case above, but you can
always intersect the osr_value bounds.

+  }
+}
+
+
 bool OsrHelper::Deconstruct(JSGraph* jsgraph, CommonOperatorBuilder* common,
                             Zone* tmp_zone) {
   Graph* graph = jsgraph->graph();
   Node* osr_normal_entry = nullptr;
   Node* osr_loop_entry = nullptr;
   Node* osr_loop = nullptr;
 
   for (Node* node : graph->start()->uses()) {
     if (node->opcode() == IrOpcode::kOsrLoopEntry) {
       osr_loop_entry = node;  // found the OSR loop entry
@@ skipping 10 matching lines @@
 
   for (Node* use : osr_loop_entry->uses()) {
     if (use->opcode() == IrOpcode::kLoop) {
       CHECK(!osr_loop);             // should be only one OSR loop.
       osr_loop = use;               // found the OSR loop.
     }
   }
 
   CHECK(osr_loop);  // Should have found the OSR loop.
 
+  // Transfer the types from loop phis to the OSR values which flow into them.
+  TransferOsrValueTypesFromLoopPhis(graph->zone(), osr_loop_entry, osr_loop);
+
   // Analyze the graph to determine how deeply nested the OSR loop is.
   LoopTree* loop_tree = LoopFinder::BuildLoopTree(graph, tmp_zone);
 
   Node* dead = graph->NewNode(common->Dead());
   LoopTree::Loop* loop = loop_tree->ContainingLoop(osr_loop);
   if (loop->depth() > 0) {
     PeelOuterLoopsForOsr(graph, common, tmp_zone, dead, loop_tree, loop,
                          osr_normal_entry, osr_loop_entry);
   }
 
@@ skipping 12 matching lines @@
   // the first spill slots.
   frame->ReserveSpillSlots(UnoptimizedFrameSlots());
   // The frame needs to be adjusted by the number of unoptimized frame slots.
   frame->SetOsrStackSlotCount(static_cast<int>(UnoptimizedFrameSlots()));
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8