diff --git a/enzyme/Enzyme/EnzymeLogic.cpp b/enzyme/Enzyme/EnzymeLogic.cpp
index 3796125ed8df..3f1cf5ad0a9d 100644
--- a/enzyme/Enzyme/EnzymeLogic.cpp
+++ b/enzyme/Enzyme/EnzymeLogic.cpp
@@ -327,6 +327,11 @@ struct CacheAnalysis {
         if (!inst2->mayWriteToMemory())
           return false;
 
+#if LLVM_VERSION_MAJOR >= 12
+        if (isa<FenceInst>(inst2))
+          return false;
+#endif
+
         if (unnecessaryBlocks.count(inst2->getParent())) {
           return false;
         }
@@ -352,6 +357,11 @@ struct CacheAnalysis {
                   if (!mid->mayWriteToMemory())
                     return false;
 
+#if LLVM_VERSION_MAJOR >= 12
+                  if (isa<FenceInst>(mid))
+                    return false;
+#endif
+
                   if (unnecessaryBlocks.count(mid->getParent())) {
                     return false;
                   }