Fix a gcroot lowering bug.

llvm-svn: 41668
diff --git a/llvm/test/CodeGen/Generic/GC/lower_gcroot.ll b/llvm/test/CodeGen/Generic/GC/lower_gcroot.ll
new file mode 100644
index 0000000..3a3abac
--- /dev/null
+++ b/llvm/test/CodeGen/Generic/GC/lower_gcroot.ll
@@ -0,0 +1,10 @@
+; RUN: llvm-as < %s | llc
+
+	%Env = type opaque*
+
+define void @.main(%Env) {
+	call void @llvm.gcroot( %Env* null, %Env null )
+	unreachable
+}
+
+declare void @llvm.gcroot(%Env*, %Env)