[csa][cleanup] TNodify LoadElementAndPrepareForStore's return value

Bug: v8:6949, v8:11384
Change-Id: Ief5a14e5c4327adb8fe9c12fd4af72596a1ba20a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2692209Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72703}

src/codegen/code-stub-assembler.cc

@@ -4867,19 +4867,24 @@ void CodeStubAssembler::CopyFixedArrayElements(
       if_hole = nullptr;
     }
 
-    Node* value = LoadElementAndPrepareForStore(
-        from_array, var_from_offset.value(), from_kind, to_kind, if_hole);
-
-    if (needs_write_barrier) {
-      CHECK_EQ(to_array, to_array_adjusted);
-      Store(to_array_adjusted, to_offset, value);
-    } else if (to_double_elements) {
+    if (to_double_elements) {
+      DCHECK(!needs_write_barrier);
+      TNode<Float64T> value = LoadElementAndPrepareForStore<Float64T>(
+          from_array, var_from_offset.value(), from_kind, to_kind, if_hole);
       StoreNoWriteBarrier(MachineRepresentation::kFloat64, to_array_adjusted,
                           to_offset, value);
     } else {
-      UnsafeStoreNoWriteBarrier(MachineRepresentation::kTagged,
-                                to_array_adjusted, to_offset, value);
+      TNode<Object> value = LoadElementAndPrepareForStore<Object>(
+          from_array, var_from_offset.value(), from_kind, to_kind, if_hole);
+      if (needs_write_barrier) {
+        CHECK_EQ(to_array, to_array_adjusted);
+        Store(to_array_adjusted, to_offset, value);
+      } else {
+        UnsafeStoreNoWriteBarrier(MachineRepresentation::kTagged,
+                                  to_array_adjusted, to_offset, value);
+      }
     }
+
     Goto(&next_iter);
 
     if (if_hole == &store_double_hole) {
@@ -4991,30 +4996,43 @@ TNode<FixedArrayBase> CodeStubAssembler::CloneFixedArray(
       base::Optional<TNode<BInt>>(base::nullopt), flags);
 }
 
-Node* CodeStubAssembler::LoadElementAndPrepareForStore(
+template <>
+TNode<Object> CodeStubAssembler::LoadElementAndPrepareForStore(
     TNode<FixedArrayBase> array, TNode<IntPtrT> offset, ElementsKind from_kind,
     ElementsKind to_kind, Label* if_hole) {
   CSA_ASSERT(this, IsFixedArrayWithKind(array, from_kind));
+  DCHECK(!IsDoubleElementsKind(to_kind));
   if (IsDoubleElementsKind(from_kind)) {
     TNode<Float64T> value =
         LoadDoubleWithHoleCheck(array, offset, if_hole, MachineType::Float64());
-    if (!IsDoubleElementsKind(to_kind)) {
-      return AllocateHeapNumberWithValue(value);
+    return AllocateHeapNumberWithValue(value);
+  } else {
+    TNode<Object> value = Load<Object>(array, offset);
+    if (if_hole) {
+      GotoIf(TaggedEqual(value, TheHoleConstant()), if_hole);
     }
     return value;
+  }
+}
 
+template <>
+TNode<Float64T> CodeStubAssembler::LoadElementAndPrepareForStore(
+    TNode<FixedArrayBase> array, TNode<IntPtrT> offset, ElementsKind from_kind,
+    ElementsKind to_kind, Label* if_hole) {
+  CSA_ASSERT(this, IsFixedArrayWithKind(array, from_kind));
+  DCHECK(IsDoubleElementsKind(to_kind));
+  if (IsDoubleElementsKind(from_kind)) {
+    return LoadDoubleWithHoleCheck(array, offset, if_hole,
+                                   MachineType::Float64());
   } else {
     TNode<Object> value = Load<Object>(array, offset);
     if (if_hole) {
       GotoIf(TaggedEqual(value, TheHoleConstant()), if_hole);
     }
-    if (IsDoubleElementsKind(to_kind)) {
-      if (IsSmiElementsKind(from_kind)) {
-        return SmiToFloat64(CAST(value));
-      }
-      return LoadHeapNumberValue(CAST(value));
+    if (IsSmiElementsKind(from_kind)) {
+      return SmiToFloat64(CAST(value));
     }
-    return value;
+    return LoadHeapNumberValue(CAST(value));
   }
 }
 

src/codegen/code-stub-assembler.h

@@ -2168,10 +2168,12 @@ class V8_EXPORT_PRIVATE CodeStubAssembler
   // (NOTE: not index!), does a hole check if |if_hole| is provided and
   // converts the value so that it becomes ready for storing to array of
   // |to_kind| elements.
-  Node* LoadElementAndPrepareForStore(TNode<FixedArrayBase> array,
-                                      TNode<IntPtrT> offset,
-                                      ElementsKind from_kind,
-                                      ElementsKind to_kind, Label* if_hole);
+  template <typename TResult>
+  TNode<TResult> LoadElementAndPrepareForStore(TNode<FixedArrayBase> array,
+                                               TNode<IntPtrT> offset,
+                                               ElementsKind from_kind,
+                                               ElementsKind to_kind,
+                                               Label* if_hole);
 
   template <typename TIndex>
   TNode<TIndex> CalculateNewElementsCapacity(TNode<TIndex> old_capacity);