diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index 7145581..02e17d3 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -1093,6 +1093,7 @@
       I2->replaceAllUsesWith(I1);
     I1->intersectOptionalDataWith(I2);
     unsigned KnownIDs[] = {
+      LLVMContext::MD_dbg,
       LLVMContext::MD_tbaa,
       LLVMContext::MD_range,
       LLVMContext::MD_fpmath,