diff --git a/compiler/optimizing/optimization.h b/compiler/optimizing/optimization.h
index 88b283c..a9fafa0 100644
--- a/compiler/optimizing/optimization.h
+++ b/compiler/optimizing/optimization.h
@@ -101,6 +101,7 @@
 #endif
 #if defined(ART_ENABLE_CODEGEN_x86) || defined(ART_ENABLE_CODEGEN_x86_64)
   kX86MemoryOperandGeneration,
+  kInstructionSimplifierX86,
 #endif
   kNone,
   kLast = kNone