diff --git a/src/cpu/o3/dyn_inst.hh b/src/cpu/o3/dyn_inst.hh
index 34afa2d1b3..a2cdf2dba4 100644
--- a/src/cpu/o3/dyn_inst.hh
+++ b/src/cpu/o3/dyn_inst.hh
@@ -31,6 +31,7 @@
 #ifndef __CPU_O3_DYN_INST_HH__
 #define __CPU_O3_DYN_INST_HH__
 
+#include "arch/isa_specific.hh"
 
 #if THE_ISA == ALPHA_ISA
 template <class Impl>