[turbofan] Exhaustive switches for MachineRepresentation.

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

Index: src/compiler/mips/instruction-selector-mips.cc
diff --git a/src/compiler/mips/instruction-selector-mips.cc b/src/compiler/mips/instruction-selector-mips.cc
index 251d43919644c5c71811c79c404255a186c56bc1..45a1910e7874262708f92059423aaacc1935f998 100644
--- a/src/compiler/mips/instruction-selector-mips.cc
+++ b/src/compiler/mips/instruction-selector-mips.cc
@@ -132,7 +132,7 @@ void InstructionSelector::VisitLoad(Node* node) {
   Node* base = node->InputAt(0);
   Node* index = node->InputAt(1);
 
-  ArchOpcode opcode;
+  ArchOpcode opcode = kArchNop;
   switch (load_rep.representation()) {
     case MachineRepresentation::kFloat32:
       opcode = kMipsLwc1;
@@ -151,7 +151,8 @@ void InstructionSelector::VisitLoad(Node* node) {
     case MachineRepresentation::kWord32:
       opcode = kMipsLw;
       break;
-    default:
+    case MachineRepresentation::kWord64:  // Fall through.
+    case MachineRepresentation::kNone:
       UNREACHABLE();
       return;
   }
@@ -211,7 +212,7 @@ void InstructionSelector::VisitStore(Node* node) {
     code |= MiscField::encode(static_cast<int>(record_write_mode));
     Emit(code, 0, nullptr, input_count, inputs, temp_count, temps);
   } else {
-    ArchOpcode opcode;
+    ArchOpcode opcode = kArchNop;
     switch (rep) {
       case MachineRepresentation::kFloat32:
         opcode = kMipsSwc1;
@@ -230,7 +231,8 @@ void InstructionSelector::VisitStore(Node* node) {
       case MachineRepresentation::kWord32:
         opcode = kMipsSw;
         break;
-      default:
+      case MachineRepresentation::kWord64:  // Fall through.
+      case MachineRepresentation::kNone:
         UNREACHABLE();
         return;
     }
@@ -850,7 +852,7 @@ void InstructionSelector::VisitCheckedLoad(Node* node) {
   Node* const buffer = node->InputAt(0);
   Node* const offset = node->InputAt(1);
   Node* const length = node->InputAt(2);
-  ArchOpcode opcode;
+  ArchOpcode opcode = kArchNop;
   switch (load_rep.representation()) {
     case MachineRepresentation::kWord8:
       opcode = load_rep.IsSigned() ? kCheckedLoadInt8 : kCheckedLoadUint8;
@@ -867,7 +869,10 @@ void InstructionSelector::VisitCheckedLoad(Node* node) {
     case MachineRepresentation::kFloat64:
       opcode = kCheckedLoadFloat64;
       break;
-    default:
+    case MachineRepresentation::kBit:     // Fall through.
+    case MachineRepresentation::kTagged:  // Fall through.
+    case MachineRepresentation::kWord64:  // Fall through.
+    case MachineRepresentation::kNone:
       UNREACHABLE();
       return;
   }
@@ -894,7 +899,7 @@ void InstructionSelector::VisitCheckedStore(Node* node) {
   Node* const offset = node->InputAt(1);
   Node* const length = node->InputAt(2);
   Node* const value = node->InputAt(3);
-  ArchOpcode opcode;
+  ArchOpcode opcode = kArchNop;
   switch (rep) {
     case MachineRepresentation::kWord8:
       opcode = kCheckedStoreWord8;