diff --git a/src/libCom/osi/compiler/gcc/epicsAtomicCD.h b/src/libCom/osi/compiler/gcc/epicsAtomicCD.h
index c706a31a0..e3989769f 100644
--- a/src/libCom/osi/compiler/gcc/epicsAtomicCD.h
+++ b/src/libCom/osi/compiler/gcc/epicsAtomicCD.h
@@ -86,7 +86,7 @@ EPICS_ATOMIC_INLINE void epicsAtomicWriteMemoryBarrier ()
 #else
 
 #ifndef EPICS_ATOMIC_READ_MEMORY_BARRIER
-#ifdef GCC_ATOMIC_INTRINSICS_MIN_X86
+#if GCC_ATOMIC_INTRINSICS_MIN_X86
 #define EPICS_ATOMIC_READ_MEMORY_BARRIER
 EPICS_ATOMIC_INLINE void epicsAtomicReadMemoryBarrier ()
 {
@@ -96,7 +96,7 @@ EPICS_ATOMIC_INLINE void epicsAtomicReadMemoryBarrier ()
 #endif
 
 #ifndef EPICS_ATOMIC_WRITE_MEMORY_BARRIER
-#ifdef GCC_ATOMIC_INTRINSICS_MIN_X86
+#if GCC_ATOMIC_INTRINSICS_MIN_X86
 #define EPICS_ATOMIC_WRITE_MEMORY_BARRIER
 EPICS_ATOMIC_INLINE void epicsAtomicWriteMemoryBarrier ()
 {