[backend] Allow LoadImmutable when Load is allowed

When introducing LoadImmutable, we missed a couple of places where it
can be used like Load.

Change-Id: If02f6f1ad01d9b68ee757b38689e9f6336a6fb1d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3118545Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76512}

src/compiler/backend/arm64/instruction-selector-arm64.cc

@@ -1932,7 +1932,9 @@ void InstructionSelector::VisitBitcastWord32ToWord64(Node* node) {
 
 void InstructionSelector::VisitChangeInt32ToInt64(Node* node) {
   Node* value = node->InputAt(0);
-  if (value->opcode() == IrOpcode::kLoad && CanCover(node, value)) {
+  if ((value->opcode() == IrOpcode::kLoad ||
+       value->opcode() == IrOpcode::kLoadImmutable) &&
+      CanCover(node, value)) {
     // Generate sign-extending load.
     LoadRepresentation load_rep = LoadRepresentationOf(value->op());
     MachineRepresentation rep = load_rep.representation();

src/compiler/backend/loong64/instruction-selector-loong64.cc

@@ -1357,7 +1357,9 @@ void InstructionSelector::VisitBitcastWord32ToWord64(Node* node) {
 void InstructionSelector::VisitChangeInt32ToInt64(Node* node) {
 #ifdef USE_SIMULATOR
   Node* value = node->InputAt(0);
-  if (value->opcode() == IrOpcode::kLoad && CanCover(node, value)) {
+  if ((value->opcode() == IrOpcode::kLoad || ||
+       value->opcode() == IrOpcode::kLoadImmutable) &&
+      CanCover(node, value)) {
     // Generate sign-extending load.
     LoadRepresentation load_rep = LoadRepresentationOf(value->op());
     InstructionCode opcode = kArchNop;