Support Int32 representation for selected binary operations.

runtime/vm/flow_graph_optimizer.h

Index: runtime/vm/flow_graph_optimizer.h
diff --git a/runtime/vm/flow_graph_optimizer.h b/runtime/vm/flow_graph_optimizer.h
index 376b1e7ab6a1ca2a498a7283746dc9939e639bf3..8f6c260c426bfa0f8d0bfdf7e2197e1d7391e8d7 100644
--- a/runtime/vm/flow_graph_optimizer.h
+++ b/runtime/vm/flow_graph_optimizer.h
@@ -41,6 +41,8 @@ class FlowGraphOptimizer : public FlowGraphVisitor {
 
   void SelectRepresentations();
 
+  void WidenSmiToInt32();
+
   void InferIntRanges();
 
   void SelectIntegerInstructions();
@@ -268,6 +270,8 @@ class LICM : public ValueObject {
 
   void Optimize();
 
+  void OptimisticallySpecializeSmiPhis();
+
  private:
   FlowGraph* flow_graph() const { return flow_graph_; }
 
@@ -275,10 +279,9 @@ class LICM : public ValueObject {
              BlockEntryInstr* pre_header,
              Instruction* current);
 
-  void TryHoistCheckSmiThroughPhi(ForwardInstructionIterator* it,
-                                  BlockEntryInstr* header,
-                                  BlockEntryInstr* pre_header,
-                                  CheckSmiInstr* current);
+  void TrySpecializeSmiPhi(PhiInstr* phi,
+                           BlockEntryInstr* header,
+                           BlockEntryInstr* pre_header);
 
   FlowGraph* const flow_graph_;
 };