Index: test/ELF/arm-thumb-undefined-weak-narrow.s
===================================================================
--- /dev/null
+++ test/ELF/arm-thumb-undefined-weak-narrow.s
@@ -0,0 +1,21 @@
+// REQUIRES: arm
+// RUN: ld.lld %S/Inputs/arm-thumb-narrow-undefined-weak.o -o %t
+// RUN: llvm-objdump -triple=thumbv7a-linux-gnueabi -d %t | FileCheck %s
+
+// CHECK: Disassembly of section .text:
+// CHECK-NEXT: __start:
+// CHECK-NEXT:    11000:       ff e7   b       #-2
+
+// llvm-mc relaxes the b.n to a b.w as undefined_weak is external to the
+// section so we must use a binary object produced by GNU as. It can be
+// reproduced with arm-linux-gnueabihf-gcc -c filename.s -o filename.o where
+// filename.s contains the code below. The object in Inputs was produced
+// by arm-linux-gnueabihf-gcc (Linaro GCC 5.3-2016.02) 5.3.1 20160113
+//
+//        .thumb
+//        .syntax unified
+//
+//        .weak undefined_weak
+//        .globl _start
+//        .type _start, %function
+// __start: b.n undefine_weak