Index: src/x64/ic-x64.cc |
diff --git a/src/x64/ic-x64.cc b/src/x64/ic-x64.cc |
index ce91eff5351148bd0f3d9c4db9ff4dd7cf7368fd..82112a0bea0fbe0b055edf64198b33bbc0c462a2 100644 |
--- a/src/x64/ic-x64.cc |
+++ b/src/x64/ic-x64.cc |
@@ -337,7 +337,8 @@ static void GenerateKeyNameCheck(MacroAssembler* masm, |
__ testl(hash, Immediate(Name::kContainsCachedArrayIndexMask)); |
__ j(zero, index_string); // The value in hash is used at jump target. |
- // Is the string internalized? |
+ // Is the string internalized? We already know it's a string so a single |
+ // bit test is enough. |
STATIC_ASSERT(kInternalizedTag != 0); |
__ testb(FieldOperand(map, Map::kInstanceTypeOffset), |
Immediate(kIsInternalizedMask)); |