Speculate on bitwise operators.

runtime/vm/intermediate_language_mips.cc

 // Copyright (c) 2013, 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/globals.h"  // Needed here to get TARGET_ARCH_MIPS.
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/compiler.h"
@@ skipping 3021 matching lines @@
       if (!combined_smi_check) {
         __ or_(result, left, right);
       }
       break;
     case Token::kBIT_AND:
       __ and_(result, left, right);
       break;
     case Token::kBIT_XOR:
       __ xor_(result, left, right);
       break;
+    case Token::kSHL:
+      ASSERT(result != left);
+      ASSERT(result != right);
+      __ BranchUnsignedGreater(right, Immediate(Smi::RawValue(Smi::kBits)),
+                               slow_path->entry_label());
+      // Check for overflow by shifting left and shifting back arithmetically.
+      // If the result is different from the original, there was overflow.
+      __ delay_slot()->SmiUntag(TMP, right);
+      __ sllv(result, left, TMP);
+      __ srav(CMPRES1, result, TMP);
+      __ bne(CMPRES1, left, slow_path->entry_label());
+      break;
+    case Token::kSHR:
+      __ BranchUnsignedGreater(right, Immediate(Smi::RawValue(Smi::kBits)),
+                               slow_path->entry_label());
+      __ delay_slot()->SmiUntag(result, right);
+      __ SmiUntag(TMP, left);
+      __ srav(result, TMP, result);
+      __ SmiTag(result);
+      break;
     default:
       UNIMPLEMENTED();
   }
   __ Bind(slow_path->exit_label());
 }
 
 
 class CheckedSmiComparisonSlowPath : public SlowPathCode {
  public:
   CheckedSmiComparisonSlowPath(CheckedSmiComparisonInstr* instruction,
@@ skipping 2932 matching lines @@
   compiler->GenerateRuntimeCall(TokenPosition::kNoSource, deopt_id(),
                                 kGrowRegExpStackRuntimeEntry, 1, locs());
   __ lw(result, Address(SP, 1 * kWordSize));
   __ addiu(SP, SP, Immediate(2 * kWordSize));
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS