[compiler] No need to push literal index in VisitArrayLiteral.

src/compiler/ast-graph-builder.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/ast-graph-builder.h"
 
 #include "src/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
 #include "src/compiler/linkage.h"
@@ skipping 1899 matching lines @@
   Node* literals_array =
       BuildLoadObjectField(closure, JSFunction::kLiteralsOffset);
   Node* literal_index = jsgraph()->Constant(expr->literal_index());
   Node* constants = jsgraph()->Constant(expr->constant_elements());
   const Operator* op =
       javascript()->CreateLiteralArray(expr->ComputeFlags(true));
   Node* literal = NewNode(op, literals_array, literal_index, constants);
   PrepareFrameState(literal, expr->CreateLiteralId(),
                     OutputFrameStateCombine::Push());
 
-  // The array and the literal index are both expected on the operand stack
-  // during computation of the element values.
+  // The array is expected on the operand stack during computation of the
+  // element values.
   environment()->Push(literal);
-  environment()->Push(literal_index);
 
   // Create nodes to evaluate all the non-constant subexpressions and to store
   // them into the newly cloned array.
   int array_index = 0;
   for (; array_index < expr->values()->length(); array_index++) {
     Expression* subexpr = expr->values()->at(array_index);
     if (subexpr->IsSpread()) break;
     if (CompileTimeValue::IsCompileTimeValue(subexpr)) continue;
 
     VisitForValue(subexpr);
     {
       FrameStateBeforeAndAfter states(this, subexpr->id());
       VectorSlotPair pair = CreateVectorSlotPair(expr->LiteralFeedbackSlot());
       Node* value = environment()->Pop();
       Node* index = jsgraph()->Constant(array_index);
-      Node* literal = environment()->Peek(1);
+      Node* literal = environment()->Top();
       Node* store = BuildKeyedStore(literal, index, value, pair);
       states.AddToNode(store, expr->GetIdForElement(array_index),
                        OutputFrameStateCombine::Ignore());
     }
   }
 
   // In case the array literal contains spread expressions it has two parts. The
   // first part is  the "static" array which has a literal index is handled
   // above. The second part is the part after the first spread expression
   // (inclusive) and these elements gets appended to the array. Note that the
   // number elements an iterable produces is unknown ahead of time.
-  environment()->Pop();  // Array literal index.
   for (; array_index < expr->values()->length(); array_index++) {
     Expression* subexpr = expr->values()->at(array_index);
     Node* result;
 
     if (subexpr->IsSpread()) {
       VisitForValue(subexpr->AsSpread()->expression());
       FrameStateBeforeAndAfter states(this,
                                       subexpr->AsSpread()->expression()->id());
       Node* iterable = environment()->Pop();
       Node* array = environment()->Pop();
@@ skipping 2347 matching lines @@
     // Phi does not exist yet, introduce one.
     value = NewPhi(inputs, value, control);
     value->ReplaceInput(inputs - 1, other);
   }
   return value;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8