diff --git a/lib/Target/ARM/ARMInstrInfo.td b/lib/Target/ARM/ARMInstrInfo.td
index 5d5380f34c9..1bd174e3416 100644
--- a/lib/Target/ARM/ARMInstrInfo.td
+++ b/lib/Target/ARM/ARMInstrInfo.td
@@ -2313,6 +2313,7 @@ multiclass AI2_ldridx<bit isByte, string opc,
      let Inst{23} = offset{12};
      let Inst{19-16} = addr;
      let Inst{11-0} = offset{11-0};
+     let Inst{4} = 0;
 
     let DecoderMethod = "DecodeAddrMode2IdxInstruction";
    }
diff --git a/test/MC/Disassembler/ARM/invalid-LDR_POST-arm.txt b/test/MC/Disassembler/ARM/invalid-LDR_POST-arm.txt
index 0cff28ad2b2..ecab5a5758e 100644
--- a/test/MC/Disassembler/ARM/invalid-LDR_POST-arm.txt
+++ b/test/MC/Disassembler/ARM/invalid-LDR_POST-arm.txt
@@ -1,5 +1,4 @@
 # RUN: llvm-mc --disassemble %s -triple=arm-apple-darwin9 2>&1 | grep "invalid instruction encoding"
-# XFAIL: *
 
 # LDR_PRE/POST has encoding Inst{4} = 0.
 0xde 0x69 0x18 0x46