With --noopt run unoptimized code through optimizer, more optimizations can be done later.

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 ae31c415a40a9e13c5b5fd7f7be16c903418a41b..fc9e0cb215cc22d7f2f83e266d8aaad013c5148d 100644
--- a/runtime/vm/flow_graph_compiler.cc
+++ b/runtime/vm/flow_graph_compiler.cc
@@ -8,6 +8,7 @@
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
+#include "vm/compiler.h"
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
 #include "vm/deopt_instructions.h"
@@ -54,7 +55,6 @@ DECLARE_FLAG(int, reoptimization_counter_threshold);
 DECLARE_FLAG(int, stacktrace_every);
 DECLARE_FLAG(charp, stacktrace_filter);
 DECLARE_FLAG(bool, support_debugger);
-DECLARE_FLAG(bool, use_cha);
 DECLARE_FLAG(bool, use_field_guards);
 DECLARE_FLAG(bool, use_osr);
 DECLARE_FLAG(bool, warn_on_javascript_compatibility);
@@ -70,6 +70,8 @@ static void NooptModeHandler(bool value) {
     FLAG_support_debugger = false;
     FLAG_ic_range_profiling = false;
     FLAG_collect_code = false;
+    Compiler::set_always_optimize(true);
+    Compiler::set_guess_other_cid(false);
   }
 }
 
@@ -206,7 +208,6 @@ void FlowGraphCompiler::InitCompiler() {
         const ICData* ic_data = NULL;
         if (current->IsInstanceCall()) {
           ic_data = current->AsInstanceCall()->ic_data();
-          ASSERT(ic_data != NULL);
         }
         if ((ic_data != NULL) && (ic_data->NumberOfUsedChecks() == 0)) {
           may_reoptimize_ = true;
@@ -846,6 +847,8 @@ Label* FlowGraphCompiler::AddDeoptStub(intptr_t deopt_id,
     return &intrinsic_slow_path_label_;
   }
 
+  // No deoptimization allowed when 'always_optimize' is set.
+  ASSERT(!Compiler::always_optimize());
   ASSERT(is_optimizing_);
   CompilerDeoptInfoWithStub* stub =
       new CompilerDeoptInfoWithStub(deopt_id,
@@ -881,6 +884,10 @@ void FlowGraphCompiler::FinalizePcDescriptors(const Code& code) {
 
 
 RawArray* FlowGraphCompiler::CreateDeoptInfo(Assembler* assembler) {
+  // No deopt information if we 'always_optimize' (no deoptimization allowed).
+  if (Compiler::always_optimize()) {
+    return Array::empty_array().raw();
+  }
   // For functions with optional arguments, all incoming arguments are copied
   // to spill slots. The deoptimization environment does not track them.
   const Function& function = parsed_function().function();