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

src/compiler/osr.cc

Index: src/compiler/osr.cc
diff --git a/src/compiler/osr.cc b/src/compiler/osr.cc
index 2eccf302f50212f49d44eebd8d27c32193a4aa25..533c293b195bb1831412520d72fcf6d17e04c17b 100644
--- a/src/compiler/osr.cc
+++ b/src/compiler/osr.cc
@@ -174,6 +174,33 @@ static void PeelOuterLoopsForOsr(Graph* graph, CommonOperatorBuilder* common,
 }
 
 
+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.
+        NodeProperties::SetBounds(osr_value, NodeProperties::GetBounds(phi));

[Jarin, 2015/02/16 14:33:03]

As discussed offline, we should combine the types of all phis rather than using
just one phi to type the osr value.

+        unknown = false;
+      }
+    }
+    if (unknown) NodeProperties::SetBounds(osr_value, Bounds::Unbounded(zone));
+  }
+}
+
+
 bool OsrHelper::Deconstruct(JSGraph* jsgraph, CommonOperatorBuilder* common,
                             Zone* tmp_zone) {
   Graph* graph = jsgraph->graph();
@@ -204,6 +231,9 @@ bool OsrHelper::Deconstruct(JSGraph* jsgraph, CommonOperatorBuilder* common,
 
   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);