Speculate on bitwise operators.

runtime/vm/intermediate_language_arm64.cc

Index: runtime/vm/intermediate_language_arm64.cc
diff --git a/runtime/vm/intermediate_language_arm64.cc b/runtime/vm/intermediate_language_arm64.cc
index 1e4baa2673825cf84df5182a5843281c0fd81d62..fa404f501b536b6f46105d936c91046cdc54bc25 100644
--- a/runtime/vm/intermediate_language_arm64.cc
+++ b/runtime/vm/intermediate_language_arm64.cc
@@ -2954,6 +2954,34 @@ void CheckedSmiOpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
     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();
   }