Faster 64-bit left-shift for ia32.

runtime/vm/flow_graph_optimizer.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/flow_graph_optimizer.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/flow_graph_compiler.h"
@@ skipping 504 matching lines @@
       if (HasOnlyTwoSmis(ic_data)) {
         operands_type = kSmiCid;
       } else if (HasTwoMintOrSmi(ic_data) &&
                  FlowGraphCompiler::SupportsUnboxedMints()) {
         operands_type = kMintCid;
       } else {
         return false;
       }
       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 {
         return false;
       }
       break;
     default:
       UNREACHABLE();
   };
 
@@ skipping 11 matching lines @@
                  call->env(),
                  Definition::kEffect);
 
     BinaryDoubleOpInstr* double_bin_op =
         new BinaryDoubleOpInstr(op_kind, left->Copy(), right->Copy(), call);
     call->ReplaceWith(double_bin_op, current_iterator());
     RemovePushArguments(call);
   } 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());
     } else {
       BinaryMintOpInstr* bin_op =
           new BinaryMintOpInstr(op_kind, left, right, call);
       call->ReplaceWith(bin_op, current_iterator());
     }
     RemovePushArguments(call);
   } else if (op_kind == Token::kMOD) {
@@ skipping 2671 matching lines @@
 
   if (FLAG_trace_constant_propagation) {
     OS::Print("\n==== After constant propagation ====\n");
     FlowGraphPrinter printer(*graph_);
     printer.PrintBlocks();
   }
 }
 
 
 }  // namespace dart