IR refactoring: consolidate all boxing and unboxing instructions.

runtime/vm/flow_graph_compiler.cc

Index: runtime/vm/flow_graph_compiler.cc
diff --git a/runtime/vm/flow_graph_compiler.cc b/runtime/vm/flow_graph_compiler.cc
index d3258f98b9d11c36a6e0f21420fb38afc0882a71..372ec5a0a557ccb5fa843a80442c88236d5f86cf 100644
--- a/runtime/vm/flow_graph_compiler.cc
+++ b/runtime/vm/flow_graph_compiler.cc
@@ -1497,4 +1497,24 @@ intptr_t FlowGraphCompiler::GetOptimizationThreshold() const {
   return threshold;
 }
 
+
+const Class& FlowGraphCompiler::BoxClassFor(Representation rep) {
+  switch (rep) {
+    case kUnboxedDouble:
+      return double_class();
+    case kUnboxedFloat32x4:
+      return float32x4_class();
+    case kUnboxedFloat64x2:
+      return float64x2_class();
+    case kUnboxedInt32x4:
+      return int32x4_class();
+    case kUnboxedMint:
+      return mint_class();
+    default:
+      UNREACHABLE();
+      return Class::ZoneHandle();
+  }
+}
+
+
 }  // namespace dart