Add stack check in loops so that loops can be stopped. Optimize relational operations.

runtime/vm/intermediate_language.cc

Index: runtime/vm/intermediate_language.cc
===================================================================
--- runtime/vm/intermediate_language.cc	(revision 8493)
+++ runtime/vm/intermediate_language.cc	(working copy)
@@ -414,6 +414,11 @@
 }
 
 
+RawAbstractType* RelationalOpComp::StaticType() const {
+  return Type::BoolInterface();
+}
+
+
 RawAbstractType* NativeCallComp::StaticType() const {
   // The result type of the native function is identical to the result type of
   // the enclosing native Dart function. However, we prefer to check the type
@@ -586,6 +591,12 @@
 }
 
 
+RawAbstractType* CheckStackOverflowComp::StaticType() const {
+  UNREACHABLE();
+  return AbstractType::null();
+}
+
+
 RawAbstractType* BinaryOpComp::StaticType() const {
   // TODO(srdjan): Compute based on input types (ICData).
   return Type::DynamicType();