Index: ELF/MarkLive.cpp
===================================================================
--- ELF/MarkLive.cpp
+++ ELF/MarkLive.cpp
@@ -220,7 +220,8 @@
 
   auto MarkSymbol = [&](const SymbolBody *Sym) {
     if (auto *D = dyn_cast_or_null<DefinedRegular>(Sym))
-      Enqueue({cast<InputSectionBase>(D->Section), D->Value});
+      if (auto *IS = dyn_cast_or_null<InputSectionBase>(D->Section))
+        Enqueue({IS, D->Value});
   };
 
   // Add GC root symbols.
Index: test/ELF/gc-absolute.s
===================================================================
--- test/ELF/gc-absolute.s
+++ test/ELF/gc-absolute.s
@@ -0,0 +1,7 @@
+# REQUIRES: x86
+
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
+# RUN: ld.lld %t -o %t2 -shared --gc-sections
+
+.global foo
+foo = 0x123