[mips] Allowing map word to be used for other state in GC header.

Port: 5e0b94c4

Bug: v8:11624
Change-Id: I0b462dceaf4b155bf662e4fb9204a237c252b4ec
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2822273
Auto-Submit: Liu yu <liuyu@loongson.cn>
Reviewed-by: Zhao Jiazhong <zhaojiazhong-hf@loongson.cn>
Commit-Queue: Zhao Jiazhong <zhaojiazhong-hf@loongson.cn>
Cr-Commit-Position: refs/heads/master@{#73934}

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

@@ -372,8 +372,8 @@ void InstructionSelector::VisitLoad(Node* node) {
     case MachineRepresentation::kCompressedPointer:  // Fall through.
     case MachineRepresentation::kCompressed:         // Fall through.
     case MachineRepresentation::kWord64:             // Fall through.
+    case MachineRepresentation::kMapWord:            // Fall through.
     case MachineRepresentation::kNone:
-    case MachineRepresentation::kMapWord:
       UNREACHABLE();
   }
   if (node->opcode() == IrOpcode::kPoisonedLoad) {
@@ -458,6 +458,7 @@ void InstructionSelector::VisitStore(Node* node) {
       case MachineRepresentation::kCompressedPointer:  // Fall through.
       case MachineRepresentation::kCompressed:         // Fall through.
       case MachineRepresentation::kWord64:             // Fall through.
+      case MachineRepresentation::kMapWord:            // Fall through.
       case MachineRepresentation::kNone:
         UNREACHABLE();
     }
@@ -1433,8 +1434,8 @@ void InstructionSelector::VisitUnalignedLoad(Node* node) {
     case MachineRepresentation::kCompressedPointer:  // Fall through.
     case MachineRepresentation::kCompressed:         // Fall through.
     case MachineRepresentation::kWord64:             // Fall through.
+    case MachineRepresentation::kMapWord:            // Fall through.
     case MachineRepresentation::kNone:
-    case MachineRepresentation::kMapWord:
       UNREACHABLE();
   }
 
@@ -1487,6 +1488,7 @@ void InstructionSelector::VisitUnalignedStore(Node* node) {
     case MachineRepresentation::kCompressedPointer:  // Fall through.
     case MachineRepresentation::kCompressed:         // Fall through.
     case MachineRepresentation::kWord64:             // Fall through.
+    case MachineRepresentation::kMapWord:            // Fall through.
     case MachineRepresentation::kNone:
       UNREACHABLE();
   }

src/compiler/backend/mips64/instruction-selector-mips64.cc

@@ -512,8 +512,8 @@ void InstructionSelector::VisitLoad(Node* node) {
       break;
     case MachineRepresentation::kCompressedPointer:  // Fall through.
     case MachineRepresentation::kCompressed:         // Fall through.
+    case MachineRepresentation::kMapWord:            // Fall through.
     case MachineRepresentation::kNone:
-    case MachineRepresentation::kMapWord:
       UNREACHABLE();
   }
   if (node->opcode() == IrOpcode::kPoisonedLoad) {
@@ -590,6 +590,7 @@ void InstructionSelector::VisitStore(Node* node) {
         break;
       case MachineRepresentation::kCompressedPointer:  // Fall through.
       case MachineRepresentation::kCompressed:         // Fall through.
+      case MachineRepresentation::kMapWord:            // Fall through.
       case MachineRepresentation::kNone:
         UNREACHABLE();
     }
@@ -1854,8 +1855,8 @@ void InstructionSelector::VisitUnalignedLoad(Node* node) {
     case MachineRepresentation::kBit:                // Fall through.
     case MachineRepresentation::kCompressedPointer:  // Fall through.
     case MachineRepresentation::kCompressed:         // Fall through.
+    case MachineRepresentation::kMapWord:            // Fall through.
     case MachineRepresentation::kNone:
-    case MachineRepresentation::kMapWord:
       UNREACHABLE();
   }
 
@@ -1908,6 +1909,7 @@ void InstructionSelector::VisitUnalignedStore(Node* node) {
     case MachineRepresentation::kBit:                // Fall through.
     case MachineRepresentation::kCompressedPointer:  // Fall through.
     case MachineRepresentation::kCompressed:         // Fall through.
+    case MachineRepresentation::kMapWord:            // Fall through.
     case MachineRepresentation::kNone:
       UNREACHABLE();
   }