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

src/compiler/typer.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/base/flags.h"
 #include "src/bootstrapper.h"
 #include "src/compiler/graph-reducer.h"
 #include "src/compiler/js-operator.h"
 #include "src/compiler/node.h"
 #include "src/compiler/node-properties.h"
@@ skipping 605 matching lines @@
   return Bounds(Type::None(zone()), Type::Boolean(zone()));
 }
 
 
 Bounds Typer::Visitor::TypeParameter(Node* node) {
   return Bounds::Unbounded(zone());
 }
 
 
 Bounds Typer::Visitor::TypeOsrValue(Node* node) {
-  // OSR values explicitly have type {None} before OSR form is deconstructed.
   if (node->InputAt(0)->opcode() == IrOpcode::kOsrLoopEntry) {
+    // Before deconstruction, OSR values have type {None} to avoid polluting
+    // the types of phis and other nodes in the graph.
     return Bounds(Type::None(), Type::None());
   }
-  // TODO(turbofan): preserve the type of OSR values after deconstruction.
+  if (NodeProperties::IsTyped(node)) {
+    // After deconstruction, OSR values may have had a type explicitly set.
+    return NodeProperties::GetBounds(node);
+  }
+  // Otherwise, be conservative.
   return Bounds::Unbounded(zone());
 }
 
 
 Bounds Typer::Visitor::TypeInt32Constant(Node* node) {
   double number = OpParameter<int32_t>(node);
   return Bounds(Type::Intersect(
       Type::Range(number, number, zone()), Type::UntaggedSigned32(), zone()));
 }
 
@@ skipping 1538 matching lines @@
       TYPED_ARRAYS(TYPED_ARRAY_CASE)
 #undef TYPED_ARRAY_CASE
     }
   }
   return Type::Constant(value, zone());
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8