Implement correct semantics of Boolean Conversion

runtime/vm/intermediate_language_mips.cc

Index: runtime/vm/intermediate_language_mips.cc
===================================================================
--- runtime/vm/intermediate_language_mips.cc	(revision 42124)
+++ runtime/vm/intermediate_language_mips.cc	(working copy)
@@ -24,6 +24,8 @@
 namespace dart {
 
 DECLARE_FLAG(bool, emit_edge_counters);
+DECLARE_FLAG(bool, enable_asserts);
+DECLARE_FLAG(bool, enable_type_checks);
 DECLARE_FLAG(int, optimization_counter_threshold);
 DECLARE_FLAG(bool, propagate_ic_data);
 DECLARE_FLAG(bool, use_osr);
@@ -399,9 +401,15 @@
   // Call the runtime if the object is not bool::true or bool::false.
   ASSERT(locs->always_calls());
   Label done;
-  __ BranchEqual(reg, Bool::True(), &done);
-  __ BranchEqual(reg, Bool::False(), &done);
 
+  if (FLAG_enable_type_checks) {
+    __ BranchEqual(reg, Bool::True(), &done);
+    __ BranchEqual(reg, Bool::False(), &done);
+  } else {
+    ASSERT(FLAG_enable_asserts);
+    __ BranchNotEqual(reg, Object::null_instance(), &done);
+  }
+
   __ Push(reg);  // Push the source object.
   compiler->GenerateRuntimeCall(token_pos,
                                 deopt_id,