Implement kDoubleToDouble and kIntegerToDouble on ia32 and x64.

runtime/vm/flow_graph_optimizer.cc

Index: runtime/vm/flow_graph_optimizer.cc
diff --git a/runtime/vm/flow_graph_optimizer.cc b/runtime/vm/flow_graph_optimizer.cc
index 51e540a5f3fdbe412381fca26485f72d8b694211..757c08b8a956e9076bd989f6b2936e656fcdedee 100644
--- a/runtime/vm/flow_graph_optimizer.cc
+++ b/runtime/vm/flow_graph_optimizer.cc
@@ -388,12 +388,24 @@ void FlowGraphOptimizer::TryInlineInstanceMethod(InstanceCallComp* comp) {
   ASSERT(classes.length() == 1);
   MethodRecognizer::Kind recognized_kind =
       MethodRecognizer::RecognizeKind(target);
+
+  ObjectKind from_kind;
   if (recognized_kind == MethodRecognizer::kDoubleToDouble) {
-    // TODO(srdjan): Implement.
+    from_kind = kDouble;
+  } else if (recognized_kind == MethodRecognizer::kIntegerToDouble) {
+    from_kind = kSmi;
+  } else {
+    return;
   }
-  if (recognized_kind == MethodRecognizer::kIntegerToDouble) {
-    // TODO(srdjan): Implement.
+
+  if (classes[0]->id() != from_kind) {
+    return;
   }
+
+  ToDoubleComp* coerce = new ToDoubleComp(
+      comp->InputAt(0), from_kind, comp);
+  coerce->set_instr(comp->instr());
+  comp->instr()->replace_computation(coerce);
 }