Speculate on bitwise operators.

runtime/vm/intermediate_language_mips.cc

Index: runtime/vm/intermediate_language_mips.cc
diff --git a/runtime/vm/intermediate_language_mips.cc b/runtime/vm/intermediate_language_mips.cc
index ed03d1d19a80cb81d34d5c7876f904d2a9497478..2b2a971bb4a7642df934e46a0d7b4e249748c49f 100644
--- a/runtime/vm/intermediate_language_mips.cc
+++ b/runtime/vm/intermediate_language_mips.cc
@@ -3063,6 +3063,30 @@ void CheckedSmiOpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
     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.
+      __ SmiUntag(TMP, right);
+      __ sllv(result, left, TMP);
+      __ srav(CMPRES1, result, TMP);
+      __ bne(CMPRES1, left, slow_path->entry_label());
+      break;
+    case Token::kSHR:
+      __ bltz(right, slow_path->entry_label());
+      __ SmiUntag(result, right);
+
+      __ LoadImmediate(TMP, 0x1F);
+      __ slt(CMPRES1, TMP, result);  // CMPRES1 := 0x1F < result ? 1 : 0
+      __ movn(result, TMP, CMPRES1);  // result := 0x1F < result ? 0x1F : result
+      __ SmiUntag(TMP, left);
+      __ srav(result, TMP, result);
+      __ SmiTag(result);
+      break;
     default:
       UNIMPLEMENTED();
   }