Cleanup of branch code generation (no change in functionality).

runtime/vm/intermediate_language.cc

Index: runtime/vm/intermediate_language.cc
===================================================================
--- runtime/vm/intermediate_language.cc	(revision 30039)
+++ runtime/vm/intermediate_language.cc	(working copy)
@@ -487,7 +487,7 @@
 
 Instruction* Instruction::RemoveFromGraph(bool return_previous) {
   ASSERT(!IsBlockEntry());
-  ASSERT(!IsControl());
+  ASSERT(!IsBranch());
   ASSERT(!IsThrow());
   ASSERT(!IsReturn());
   ASSERT(!IsReThrow());
@@ -1089,12 +1089,12 @@
 }
 
 
-intptr_t ControlInstruction::SuccessorCount() const {
+intptr_t BranchInstr::SuccessorCount() const {
   return 2;
 }
 
 
-BlockEntryInstr* ControlInstruction::SuccessorAt(intptr_t index) const {
+BlockEntryInstr* BranchInstr::SuccessorAt(intptr_t index) const {
   if (index == 0) return true_successor_;
   if (index == 1) return false_successor_;
   UNREACHABLE();
@@ -2480,6 +2480,29 @@
 }
 
 
+static bool BindsToSmiConstant(Value* value) {
+  return value->BindsToConstant() && value->BoundConstant().IsSmi();
+}
+
+
+bool IfThenElseInstr::Supports(ComparisonInstr* comparison,
+                               Value* v1,
+                               Value* v2) {
+  if (!(comparison->IsStrictCompare() &&
+        !comparison->AsStrictCompare()->needs_number_check()) &&
+      !(comparison->IsEqualityCompare() &&
+        (comparison->AsEqualityCompare()->operation_cid() == kSmiCid))) {
+    return false;
+  }
+
+  if (!BindsToSmiConstant(v1) || !BindsToSmiConstant(v2)) {
+    return false;
+  }
+
+  return true;
+}
+
+
 void PhiInstr::InferRange() {
   RangeBoundary new_min;
   RangeBoundary new_max;