Index: llvm/trunk/lib/Target/WebAssembly/WebAssemblyLowerGlobalDtors.cpp
===================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyLowerGlobalDtors.cpp
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyLowerGlobalDtors.cpp
@@ -61,7 +61,7 @@
   LLVM_DEBUG(dbgs() << "********** Lower Global Destructors **********\n");
 
   GlobalVariable *GV = M.getGlobalVariable("llvm.global_dtors");
-  if (!GV)
+  if (!GV || !GV->hasInitializer())
     return false;
 
   const ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
Index: llvm/trunk/test/CodeGen/WebAssembly/global_dtors.ll
===================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/global_dtors.ll
+++ llvm/trunk/test/CodeGen/WebAssembly/global_dtors.ll
@@ -0,0 +1,9 @@
+; RUN: llc < %s
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
+; Check that we do not crash when attempting to lower away
+; global_dtors without a definition.
+
+@llvm.global_dtors = external global [2 x { i32, void ()*, i8* }]