Speculate on bitwise operators.

runtime/vm/intermediate_language_arm64.cc

 // Copyright (c) 2014, 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_ARM64.
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/compiler.h"
@@ skipping 2936 matching lines @@
       if (!combined_smi_check) {
         __ orr(result, left, Operand(right));
       }
       break;
     case Token::kBIT_AND:
       __ and_(result, left, Operand(right));
       break;
     case Token::kBIT_XOR:
       __ eor(result, left, Operand(right));
       break;
+    case Token::kSHL:
+      ASSERT(result != left);
+      ASSERT(result != right);
+      __ CompareImmediate(
+          right, reinterpret_cast<int64_t>(Smi::New(Smi::kBits)));
+      __ b(slow_path->entry_label(), CS);
+
+      __ SmiUntag(TMP, right);
+      __ lslv(result, left, TMP);
+      __ asrv(TMP2, result, TMP);
+      __ CompareRegisters(left, TMP2);
+      __ b(slow_path->entry_label(), NE);  // Overflow.
+      break;
+    case Token::kSHR:
+      ASSERT(result != left);
+      ASSERT(result != right);
+      __ SmiUntag(result, right);
+      __ CompareRegisters(result, ZR);
+      __ b(slow_path->entry_label(), LT);
+
+      // If shift amount is bigger than 63, set to 63.
+      __ LoadImmediate(TMP, 0x3F);
+      __ CompareRegisters(result, TMP);
+      __ csel(result, TMP, result, GT);
+      __ SmiUntag(TMP, left);
+      __ asrv(result, TMP, result);
+      __ SmiTag(result);
+      break;
     default:
       UNIMPLEMENTED();
   }
   __ Bind(slow_path->exit_label());
 }
 
 
 class CheckedSmiComparisonSlowPath : public SlowPathCode {
  public:
   CheckedSmiComparisonSlowPath(CheckedSmiComparisonInstr* instruction,
@@ skipping 3064 matching lines @@
                                 1,
                                 locs());
   __ Drop(1);
   __ Pop(result);
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64