Instead of special casing one-element interpolations, just generate a static call to _interpolateSi…

runtime/vm/flow_graph_builder.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/flow_graph_builder.h"
 
 #include "lib/invocation_mirror.h"
 #include "vm/ast_printer.h"
 #include "vm/bit_vector.h"
 #include "vm/class_finalizer.h"
@@ skipping 2369 matching lines @@
     }
     ReturnDefinition(ExitTempLocalScope(tmp_var));
   }
 }
 
 
 void EffectGraphVisitor::VisitStringInterpolateNode(
     StringInterpolateNode* node) {
   ValueGraphVisitor for_argument(owner());
   ArrayNode* arguments = node->value();
-  bool is_singleton = false;
   if (arguments->length() == 1) {
+    ZoneGrowableArray<PushArgumentInstr*>* values =
+        new(I) ZoneGrowableArray<PushArgumentInstr*>(1);
     arguments->ElementAt(0)->Visit(&for_argument);
-    is_singleton = true;
-  } else {
-    arguments->Visit(&for_argument);
+    Append(for_argument);
+    PushArgumentInstr* push_arg = PushArgument(for_argument.value());
+    values->Add(push_arg);
+    const int kNumberOfArguments = 1;
+    const Array& kNoArgumentNames = Object::null_array();
+    const Class& cls =
+        Class::Handle(Library::LookupCoreClass(Symbols::StringBase()));
+    ASSERT(!cls.IsNull());
+    const Function& function = Function::ZoneHandle(
+        isolate(),
+        Resolver::ResolveStatic(
+            cls,
+            Library::PrivateCoreLibName(Symbols::InterpolateSingle()),
+            kNumberOfArguments,
+            kNoArgumentNames));
+    StaticCallInstr* call =
+        new(I) StaticCallInstr(node->token_pos(),
+                               function,
+                               kNoArgumentNames,
+                               values,
+                               owner()->ic_data_array());
+    ReturnDefinition(call);
+    return;
   }
+  arguments->Visit(&for_argument);
   Append(for_argument);
   StringInterpolateInstr* instr =
-      new(I) StringInterpolateInstr(for_argument.value(), node->token_pos(),
-                                    is_singleton);
+      new(I) StringInterpolateInstr(for_argument.value(), node->token_pos());
   ReturnDefinition(instr);
 }
 
 
 void EffectGraphVisitor::VisitClosureNode(ClosureNode* node) {
   const Function& function = node->function();
 
   if (function.IsImplicitStaticClosureFunction()) {
     const Instance& closure =
         Instance::ZoneHandle(I, function.ImplicitStaticClosure());
@@ skipping 1855 matching lines @@
   Report::MessageF(Report::kBailout,
                    Script::Handle(function.script()),
                    function.token_pos(),
                    "FlowGraphBuilder Bailout: %s %s",
                    String::Handle(function.name()).ToCString(),
                    reason);
   UNREACHABLE();
 }
 
 }  // namespace dart