[turbofan] Simplify handling of spreads in array literals.

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/js-type-feedback.h"
@@ skipping 1978 matching lines @@
       Node* value = environment()->Pop();
       Node* index = jsgraph()->Constant(array_index);
       Node* store =
           BuildKeyedStore(literal, index, value, TypeFeedbackId::None());
       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
+  // 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.
-  bool has_spread = array_index < expr->values()->length();
-  if (has_spread) {
-    environment()->Pop();  // Array literal index.
-  }
-
+  environment()->Pop();  // Array literal index.
   for (; array_index < expr->values()->length(); array_index++) {
     Expression* subexpr = expr->values()->at(array_index);
     Node* array = environment()->Pop();
     Node* result;
 
     if (subexpr->IsSpread()) {
       VisitForValue(subexpr->AsSpread()->expression());
       Node* iterable = environment()->Pop();
       Node* builtins = BuildLoadBuiltinsObject();
       Node* function = BuildLoadObjectField(
           builtins, JSBuiltinsObject::OffsetOfFunctionWithId(
                         Builtins::CONCAT_ITERABLE_TO_ARRAY));
       result = NewNode(javascript()->CallFunction(3, NO_CALL_FUNCTION_FLAGS,
                                                   language_mode()),
                        function, array, iterable);
     } else {
       VisitForValue(subexpr);
       Node* value = environment()->Pop();
       const Operator* op =
           javascript()->CallRuntime(Runtime::kAppendElement, 2);
       result = NewNode(op, array, value);
     }
 
     PrepareFrameState(result, expr->GetIdForElement(array_index));
     environment()->Push(result);
   }
 
-  if (!has_spread) {
-    environment()->Pop();  // Array literal index.
-  }
   ast_context()->ProduceValue(environment()->Pop());
 }
 
 
 void AstGraphBuilder::VisitForInAssignment(Expression* expr, Node* value,
                                            BailoutId bailout_id) {
   DCHECK(expr->IsValidReferenceExpression());
 
   // Left-hand side can only be a property, a global or a variable slot.
   Property* property = expr->AsProperty();
@@ skipping 1735 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