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

src/compiler/ia32/code-generator-ia32.cc

Index: src/compiler/ia32/code-generator-ia32.cc
diff --git a/src/compiler/ia32/code-generator-ia32.cc b/src/compiler/ia32/code-generator-ia32.cc
index f102ef5cfb6c7d2100fe3b6a1db8a0e2aadad7a0..c21cc2df2497ecac875e6105c90f76d46cff510b 100644
--- a/src/compiler/ia32/code-generator-ia32.cc
+++ b/src/compiler/ia32/code-generator-ia32.cc
@@ -954,6 +954,10 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ cmp(esp, Operand::StaticVariable(stack_limit));
       break;
     }
+    case kCheckedLoadWord64:
+    case kCheckedStoreWord64:
+      UNREACHABLE();  // currently unsupported checked int64 load/store.
+      break;
   }
 }  // NOLINT(readability/fn_size)