1 files changed, 3 insertions, 1 deletions
diff --git a/third_party/llvm-project/DWARFEmitter.cpp b/third_party/llvm-project/DWARFEmitter.cpp
index 6e4ee6119..aa0465d9b 100644
--- a/third_party/llvm-project/DWARFEmitter.cpp
+++ b/third_party/llvm-project/DWARFEmitter.cpp
@@ -190,9 +190,11 @@ protected:
   // XXX BINARYEN Make sure we emit the right size. We should not change the
   // size as we only modify relocatable fields like addresses, and such fields
   // have a fixed size, so any change is a bug.
+  // We make an exception for AddrSizeChanged, which happens when we have run
+  // the Memory64Lowering pass to turn wasm64 into wasm32.
   void onEndCompileUnit(const DWARFYAML::Unit &CU) {
     size_t EndPos = OS.tell();
-    if (EndPos - StartPos != CU.Length.getLength()) {
+    if (EndPos - StartPos != CU.Length.getLength() && !CU.AddrSizeChanged) {
       llvm_unreachable("compile unit size was incorrect");
     }
   }