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

R=jarin@chromium.org
BUG=

Review URL: https://codereview.chromium.org/930003003

Cr-Commit-Position: refs/heads/master@{#26746}

src/compiler/osr.cc

@@ -173,6 +173,40 @@ 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.
+        Bounds phi_bounds = NodeProperties::GetBounds(phi);
+        if (unknown) {
+          NodeProperties::SetBounds(osr_value, phi_bounds);
+        } else {
+          Bounds osr_bounds = NodeProperties::GetBounds(osr_value);
+          NodeProperties::SetBounds(osr_value,
+                                    Bounds::Both(phi_bounds, osr_bounds, zone));
+        }
+        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();
@@ -203,6 +237,9 @@ 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);
 

src/compiler/typer.cc

@@ -623,11 +623,16 @@ Bounds Typer::Visitor::TypeParameter(Node* node) {
 
 
 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());
 }
 

test/cctest/compiler/test-osr.cc

@@ -158,6 +158,30 @@ TEST(Deconstruct_osr1) {
 }
 
 
+TEST(Deconstruct_osr1_type) {
+  OsrDeconstructorTester T(1);
+
+  Node* loop = T.NewOsrLoop(1);
+  Node* osr_phi =
+      T.NewOsrPhi(loop, T.jsgraph.OneConstant(), 0, T.jsgraph.ZeroConstant());
+  Type* type = Type::Signed32();
+  NodeProperties::SetBounds(osr_phi, Bounds(type, type));
+
+  Node* ret = T.graph.NewNode(T.common.Return(), osr_phi, T.start, loop);
+  T.graph.SetEnd(ret);
+
+  OsrHelper helper(0, 0);
+  helper.Deconstruct(&T.jsgraph, &T.common, T.main_zone());
+
+  CHECK_EQ(type, NodeProperties::GetBounds(T.osr_values[0]).lower);
+  CHECK_EQ(type, NodeProperties::GetBounds(T.osr_values[0]).upper);
+
+  CheckInputs(loop, T.start, loop);
+  CheckInputs(osr_phi, T.osr_values[0], T.jsgraph.ZeroConstant(), loop);
+  CheckInputs(ret, osr_phi, T.start, loop);
+}
+
+
 TEST(Deconstruct_osr_remove_prologue) {
   OsrDeconstructorTester T(1);
   Diamond d(&T.graph, &T.common, T.p0);