[optimizing] Enable x86 long support.

Change-Id: I9006972a65a1f191c45691104a960366747f9d16
diff --git a/compiler/optimizing/optimizing_compiler.cc b/compiler/optimizing/optimizing_compiler.cc
index eb98424..9971daf 100644
--- a/compiler/optimizing/optimizing_compiler.cc
+++ b/compiler/optimizing/optimizing_compiler.cc
@@ -523,7 +523,7 @@
                             dex_file,
                             dex_compilation_unit,
                             &pass_info_printer);
-  } else if (shouldOptimize && RegisterAllocator::Supports(instruction_set)) {
+  } else if (shouldOptimize && can_allocate_registers) {
     LOG(FATAL) << "Could not allocate registers in optimizing compiler";
     UNREACHABLE();
   } else {