[cleanup] Remove LoadAndUntagToWord32Root

It's unused and hinders separating read-only roots into a shared table.

Bug: v8:8562
Change-Id: I4a2889d9be5df877b2f9d11ce5146a091d864cd3
Reviewed-on: https://chromium-review.googlesource.com/c/1466963Reviewed-by: Dan Elphick <delphick@chromium.org>
Commit-Queue: Maciej Goszczycki <goszczycki@google.com>
Cr-Commit-Position: refs/heads/master@{#59539}

src/builtins/base.tq

@@ -502,7 +502,6 @@ extern macro LoadFixedTypedArrayOnHeapBackingStore(FixedTypedArrayBase): RawPtr;
 
 extern macro LoadRoot(constexpr RootIndex): Object;
 extern macro StoreRoot(constexpr RootIndex, Object): Object;
-extern macro LoadAndUntagToWord32Root(constexpr RootIndex): int32;
 
 extern runtime StringEqual(Context, String, String): Oddball;
 extern builtin StringLessThan(Context, String, String): Boolean;

src/code-stub-assembler.cc

@@ -1402,23 +1402,6 @@ TNode<IntPtrT> CodeStubAssembler::LoadAndUntagSmi(Node* base, int index) {
   }
 }
 
-TNode<Int32T> CodeStubAssembler::LoadAndUntagToWord32Root(
-    RootIndex root_index) {
-  Node* isolate_root =
-      ExternalConstant(ExternalReference::isolate_root(isolate()));
-  int offset = IsolateData::root_slot_offset(root_index);
-  if (SmiValuesAre32Bits()) {
-#if V8_TARGET_LITTLE_ENDIAN
-    offset += 4;
-#endif
-    return UncheckedCast<Int32T>(
-        Load(MachineType::Int32(), isolate_root, IntPtrConstant(offset)));
-  } else {
-    return SmiToInt32(
-        Load(MachineType::AnyTagged(), isolate_root, IntPtrConstant(offset)));
-  }
-}
-
 void CodeStubAssembler::StoreAndTagSmi(Node* base, int offset, Node* value) {
   if (SmiValuesAre32Bits()) {
     int zero_offset = offset + 4;

src/code-stub-assembler.h

@@ -839,8 +839,6 @@ class V8_EXPORT_PRIVATE CodeStubAssembler
   TNode<Int32T> LoadAndUntagToWord32ObjectField(Node* object, int offset);
   // Load a SMI and untag it.
   TNode<IntPtrT> LoadAndUntagSmi(Node* base, int index);
-  // Load a SMI root, untag it, and convert to Word32.
-  TNode<Int32T> LoadAndUntagToWord32Root(RootIndex root_index);
 
   TNode<MaybeObject> LoadMaybeWeakObjectField(SloppyTNode<HeapObject> object,
                                               int offset) {