Remove support for non-ssa optimizing code generation.

runtime/vm/flow_graph_builder.cc

Index: runtime/vm/flow_graph_builder.cc
diff --git a/runtime/vm/flow_graph_builder.cc b/runtime/vm/flow_graph_builder.cc
index 0ac71ea35103a8b0fff70fcd1b0fe0780ec014aa..300109fe0f66d963fdc98f21001011ea86e1c06d 100644
--- a/runtime/vm/flow_graph_builder.cc
+++ b/runtime/vm/flow_graph_builder.cc
@@ -27,7 +27,6 @@ DEFINE_FLAG(bool, print_flow_graph, false, "Print the IR flow graph.");
 DEFINE_FLAG(bool, trace_type_check_elimination, false,
             "Trace type check elimination at compile time.");
 DECLARE_FLAG(bool, enable_type_checks);
-DECLARE_FLAG(bool, use_ssa);
 
 
 FlowGraphBuilder::FlowGraphBuilder(const ParsedFunction& parsed_function)
@@ -2224,16 +2223,11 @@ void EffectGraphVisitor::VisitSequenceNode(SequenceNode* node) {
                                   parameter_value,
                                   parameter.type(),
                                   parameter.name());
-        if (FLAG_use_ssa) {
-          parameter_value = Bind(assert_assignable);
-          // Store the type checked argument back to its corresponding local
-          // variable so that ssa renaming detects the dependency and makes use
-          // of the checked type in type propagation.
-          Do(BuildStoreLocal(parameter, parameter_value));
-        } else {
-          // No need to store the check parameter value back when not using ssa.
-          Do(assert_assignable);
-        }
+        parameter_value = Bind(assert_assignable);
+        // Store the type checked argument back to its corresponding local
+        // variable so that ssa renaming detects the dependency and makes use
+        // of the checked type in type propagation.
+        Do(BuildStoreLocal(parameter, parameter_value));
       }
       pos++;
     }