Clean up dead code after spread desugaring

src/full-codegen/mips/full-codegen-mips.cc

Index: src/full-codegen/mips/full-codegen-mips.cc
diff --git a/src/full-codegen/mips/full-codegen-mips.cc b/src/full-codegen/mips/full-codegen-mips.cc
index 07e9fdfc947e390237878c5bc430fbfabbf96a94..31e5bb7b6e1e651d29c8a6a0f43ea3d72086f5f6 100644
--- a/src/full-codegen/mips/full-codegen-mips.cc
+++ b/src/full-codegen/mips/full-codegen-mips.cc
@@ -1717,7 +1717,7 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
   int array_index = 0;
   for (; array_index < length; array_index++) {
     Expression* subexpr = subexprs->at(array_index);
-    if (subexpr->IsSpread()) break;
+    DCHECK(!subexpr->IsSpread());
 
     // If the subexpression is a literal or a simple materialized literal it
     // is already set in the cloned array.
@@ -1754,14 +1754,9 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
     Expression* subexpr = subexprs->at(array_index);
 
     __ Push(v0);
-    if (subexpr->IsSpread()) {
-      VisitForStackValue(subexpr->AsSpread()->expression());
-      __ InvokeBuiltin(Context::CONCAT_ITERABLE_TO_ARRAY_BUILTIN_INDEX,
-                       CALL_FUNCTION);
-    } else {
-      VisitForStackValue(subexpr);
-      __ CallRuntime(Runtime::kAppendElement);
-    }
+    DCHECK(!subexpr->IsSpread());
+    VisitForStackValue(subexpr);
+    __ CallRuntime(Runtime::kAppendElement);
 
     PrepareForBailoutForId(expr->GetIdForElement(array_index), NO_REGISTERS);
   }