Index: llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
===================================================================
--- llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
+++ llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
@@ -363,7 +363,8 @@
   unsigned Kind = Fixup.getKind();
   switch (Kind) {
   default:
-    llvm_unreachable("Unknown fixup kind!");
+    if (Ctx) Ctx->reportError(Fixup.getLoc(), "bad relocation fixup type");
+    return 0;
   case FK_Data_1:
   case FK_Data_2:
   case FK_Data_4:
Index: llvm/trunk/test/MC/ARM/quad-relocation.s
===================================================================
--- llvm/trunk/test/MC/ARM/quad-relocation.s
+++ llvm/trunk/test/MC/ARM/quad-relocation.s
@@ -0,0 +1,9 @@
+@ RUN: not llvm-mc -triple arm-arm-none-eabi -filetype obj < %s -o /dev/null 2>&1 | FileCheck %s
+
+	.align 3
+symbol:
+  .quad(symbol)
+
+@ CHECK: error: bad relocation fixup type
+@ CHECK-NEXT:   .quad(symbol)
+@ CHECK-NEXT:        ^