[array] speed up array.forEach and friends by directly using in-operator

src/js/array.js

Index: src/js/array.js
diff --git a/src/js/array.js b/src/js/array.js
index 3e8af8664edbb0e14f491679e1ad6111ae3abef9..2458fa398e20f58f24ca1c18bfb3e923b0e43fad 100644
--- a/src/js/array.js
+++ b/src/js/array.js
@@ -328,10 +328,9 @@ function SparseMove(array, start_i, del_count, len, num_additional_args) {
 // because the receiver is not an array (so we have no choice) or because we
 // know we are not deleting or moving a lot of elements.
 function SimpleSlice(array, start_i, del_count, len, deleted_elements) {
-  var is_array = IS_ARRAY(array);
   for (var i = 0; i < del_count; i++) {
     var index = start_i + i;
-    if (HAS_INDEX(array, index, is_array)) {
+    if (HAS_INDEX(array, index)) {
       var current = array[index];
       %CreateDataProperty(deleted_elements, i, current);
     }
@@ -340,7 +339,6 @@ function SimpleSlice(array, start_i, del_count, len, deleted_elements) {
 
 
 function SimpleMove(array, start_i, del_count, len, num_additional_args) {
-  var is_array = IS_ARRAY(array);
   if (num_additional_args !== del_count) {
     // Move the existing elements after the elements to be deleted
     // to the right position in the resulting array.
@@ -348,7 +346,7 @@ function SimpleMove(array, start_i, del_count, len, num_additional_args) {
       for (var i = len - del_count; i > start_i; i--) {
         var from_index = i + del_count - 1;
         var to_index = i + num_additional_args - 1;
-        if (HAS_INDEX(array, from_index, is_array)) {
+        if (HAS_INDEX(array, from_index)) {
           array[to_index] = array[from_index];
         } else {
           delete array[to_index];
@@ -358,7 +356,7 @@ function SimpleMove(array, start_i, del_count, len, num_additional_args) {
       for (var i = start_i; i < len - del_count; i++) {
         var from_index = i + del_count;
         var to_index = i + num_additional_args;
-        if (HAS_INDEX(array, from_index, is_array)) {
+        if (HAS_INDEX(array, from_index)) {
           array[to_index] = array[from_index];
         } else {
           delete array[to_index];
@@ -1055,9 +1053,8 @@ function ArraySort(comparefn) {
 // or delete elements from the array.
 function InnerArrayFilter(f, receiver, array, length, result) {
   var result_length = 0;
-  var is_array = IS_ARRAY(array);
   for (var i = 0; i < length; i++) {
-    if (HAS_INDEX(array, i, is_array)) {
+    if (HAS_INDEX(array, i)) {
       var element = array[i];
       if (%_Call(f, receiver, element, i, array)) {
         %CreateDataProperty(result, result_length, element);
@@ -1086,17 +1083,16 @@ function ArrayFilter(f, receiver) {
 function InnerArrayForEach(f, receiver, array, length) {
   if (!IS_CALLABLE(f)) throw MakeTypeError(kCalledNonCallable, f);
 
-  var is_array = IS_ARRAY(array);
   if (IS_UNDEFINED(receiver)) {
     for (var i = 0; i < length; i++) {
-      if (HAS_INDEX(array, i, is_array)) {
+      if (HAS_INDEX(array, i)) {
         var element = array[i];
         f(element, i, array);
       }
     }
   } else {
     for (var i = 0; i < length; i++) {
-      if (HAS_INDEX(array, i, is_array)) {
+      if (HAS_INDEX(array, i)) {
         var element = array[i];
         %_Call(f, receiver, element, i, array);
       }
@@ -1119,9 +1115,8 @@ function ArrayForEach(f, receiver) {
 function InnerArraySome(f, receiver, array, length) {
   if (!IS_CALLABLE(f)) throw MakeTypeError(kCalledNonCallable, f);
 
-  var is_array = IS_ARRAY(array);
   for (var i = 0; i < length; i++) {
-    if (HAS_INDEX(array, i, is_array)) {
+    if (HAS_INDEX(array, i)) {
       var element = array[i];
       if (%_Call(f, receiver, element, i, array)) return true;
     }
@@ -1146,9 +1141,8 @@ function ArraySome(f, receiver) {
 function InnerArrayEvery(f, receiver, array, length) {
   if (!IS_CALLABLE(f)) throw MakeTypeError(kCalledNonCallable, f);
 
-  var is_array = IS_ARRAY(array);
   for (var i = 0; i < length; i++) {
-    if (HAS_INDEX(array, i, is_array)) {
+    if (HAS_INDEX(array, i)) {
       var element = array[i];
       if (!%_Call(f, receiver, element, i, array)) return false;
     }
@@ -1176,9 +1170,8 @@ function ArrayMap(f, receiver) {
   var length = TO_LENGTH(array.length);
   if (!IS_CALLABLE(f)) throw MakeTypeError(kCalledNonCallable, f);
   var result = ArraySpeciesCreate(array, length);
-  var is_array = IS_ARRAY(array);
   for (var i = 0; i < length; i++) {
-    if (HAS_INDEX(array, i, is_array)) {
+    if (HAS_INDEX(array, i)) {
       var element = array[i];
       %CreateDataProperty(result, i, %_Call(f, receiver, element, i, array));
     }
@@ -1317,11 +1310,10 @@ function InnerArrayReduce(callback, current, array, length, argumentsLength) {
     throw MakeTypeError(kCalledNonCallable, callback);
   }
 
-  var is_array = IS_ARRAY(array);
   var i = 0;
   find_initial: if (argumentsLength < 2) {
     for (; i < length; i++) {
-      if (HAS_INDEX(array, i, is_array)) {
+      if (HAS_INDEX(array, i)) {
         current = array[i++];
         break find_initial;
       }
@@ -1330,7 +1322,7 @@ function InnerArrayReduce(callback, current, array, length, argumentsLength) {
   }
 
   for (; i < length; i++) {
-    if (HAS_INDEX(array, i, is_array)) {
+    if (HAS_INDEX(array, i)) {
       var element = array[i];
       current = callback(current, element, i, array);
     }
@@ -1357,11 +1349,10 @@ function InnerArrayReduceRight(callback, current, array, length,
     throw MakeTypeError(kCalledNonCallable, callback);
   }
 
-  var is_array = IS_ARRAY(array);
   var i = length - 1;
   find_initial: if (argumentsLength < 2) {
     for (; i >= 0; i--) {
-      if (HAS_INDEX(array, i, is_array)) {
+      if (HAS_INDEX(array, i)) {
         current = array[i--];
         break find_initial;
       }
@@ -1370,7 +1361,7 @@ function InnerArrayReduceRight(callback, current, array, length,
   }
 
   for (; i >= 0; i--) {
-    if (HAS_INDEX(array, i, is_array)) {
+    if (HAS_INDEX(array, i)) {
       var element = array[i];
       current = callback(current, element, i, array);
     }