[turbofan] support for Int64 in CheckedLoad/CheckedStore on 64-bit platforms.

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

Index: src/compiler/mips64/instruction-selector-mips64.cc
diff --git a/src/compiler/mips64/instruction-selector-mips64.cc b/src/compiler/mips64/instruction-selector-mips64.cc
index 33d6f58c28bdfc205e4333690585041424049e2a..838b263d687e86f636e25e1a03d49f3d7af69325 100644
--- a/src/compiler/mips64/instruction-selector-mips64.cc
+++ b/src/compiler/mips64/instruction-selector-mips64.cc
@@ -841,6 +841,9 @@ void InstructionSelector::VisitCheckedLoad(Node* node) {
     case kRepWord32:
       opcode = kCheckedLoadWord32;
       break;
+    case kRepWord64:
+      opcode = kCheckedLoadWord64;
+      break;
     case kRepFloat32:
       opcode = kCheckedLoadFloat32;
       break;
@@ -885,6 +888,9 @@ void InstructionSelector::VisitCheckedStore(Node* node) {
     case kRepWord32:
       opcode = kCheckedStoreWord32;
       break;
+    case kRepWord64:
+      opcode = kCheckedStoreWord64;
+      break;
     case kRepFloat32:
       opcode = kCheckedStoreFloat32;
       break;