Faster 64-bit left-shift for ia32.

runtime/vm/flow_graph_optimizer.cc

Index: runtime/vm/flow_graph_optimizer.cc
===================================================================
--- runtime/vm/flow_graph_optimizer.cc	(revision 13352)
+++ runtime/vm/flow_graph_optimizer.cc	(working copy)
@@ -522,17 +522,20 @@
       }
       break;
     case Token::kSHR:
+    case Token::kSHL:
       if (HasOnlyTwoSmis(ic_data)) {
         operands_type = kSmiCid;
-      } else if (HasTwoMintOrSmi(ic_data) &&
-                 FlowGraphCompiler::SupportsUnboxedMints()) {
+      } else if (FlowGraphCompiler::SupportsUnboxedMints() &&
+                 HasTwoMintOrSmi(ic_data) &&
+                 HasOnlyOneSmi(ICData::Handle(
+                     ic_data.AsUnaryClassChecksForArgNr(1)))) {
+        // Check for smi/mint << smi or smi/mint >> smi.
         operands_type = kMintCid;
       } else {
         return false;
       }
       break;
     case Token::kTRUNCDIV:
-    case Token::kSHL:
       if (HasOnlyTwoSmis(ic_data)) {
         operands_type = kSmiCid;
       } else {
@@ -564,7 +567,7 @@
   } else if (operands_type == kMintCid) {
     Value* left = call->ArgumentAt(0)->value();
     Value* right = call->ArgumentAt(1)->value();
-    if (op_kind == Token::kSHR) {
+    if ((op_kind == Token::kSHR) || (op_kind == Token::kSHL)) {
       ShiftMintOpInstr* shift_op =
           new ShiftMintOpInstr(op_kind, left, right, call);
       call->ReplaceWith(shift_op, current_iterator());