Shift additional_index by element_shift_size, not shift_size.

src/ia32/lithium-codegen-ia32.cc

Index: src/ia32/lithium-codegen-ia32.cc
diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index b45c24855849f50cbeb8445f91240b728012ca9c..f262fd6ce4466916c80836df7d0fefd420ad9086 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -3325,7 +3325,8 @@ Operand LCodeGen::BuildFastArrayOperand(
     uint32_t offset,
     uint32_t additional_index) {
   Register elements_pointer_reg = ToRegister(elements_pointer);
-  int shift_size = ElementsKindToShiftSize(elements_kind);
+  int element_shift_size = ElementsKindToShiftSize(elements_kind);
+  int shift_size = element_shift_size;
   if (key->IsConstantOperand()) {
     int constant_value = ToInteger32(LConstantOperand::cast(key));
     if (constant_value & 0xF0000000) {
@@ -3343,7 +3344,7 @@ Operand LCodeGen::BuildFastArrayOperand(
     return Operand(elements_pointer_reg,
                    ToRegister(key),
                    scale_factor,
-                   offset + (additional_index << shift_size));
+                   offset + (additional_index << element_shift_size));
   }
 }