diff --git a/lib/Target/ARM/ARMInstrInfo.td b/lib/Target/ARM/ARMInstrInfo.td
index 77068222d6d..18127f398b9 100644
--- a/lib/Target/ARM/ARMInstrInfo.td
+++ b/lib/Target/ARM/ARMInstrInfo.td
@@ -991,6 +991,7 @@ multiclass AI_ldr1<bit isByte, string opc, InstrItinClass iii,
                  [(set GPR:$Rt, (opnode ldst_so_reg:$shift))]> {
     bits<4>  Rt;
     bits<17> shift;
+    let shift{4}    = 0;            // Inst{4} = 0
     let Inst{23}    = shift{12};    // U (add = ('U' == 1))
     let Inst{19-16} = shift{16-13}; // Rn
     let Inst{15-12} = Rt;
@@ -1020,6 +1021,7 @@ multiclass AI_str1<bit isByte, string opc, InstrItinClass iii,
                  [(opnode GPR:$Rt, ldst_so_reg:$shift)]> {
     bits<4> Rt;
     bits<17> shift;
+    let shift{4}    = 0;            // Inst{4} = 0
     let Inst{23}    = shift{12};    // U (add = ('U' == 1))
     let Inst{19-16} = shift{16-13}; // Rn
     let Inst{15-12} = Rt;
diff --git a/test/MC/Disassembler/ARM/invalid-LDRrs-arm.txt b/test/MC/Disassembler/ARM/invalid-LDRrs-arm.txt
new file mode 100644
index 00000000000..23a0b85f361
--- /dev/null
+++ b/test/MC/Disassembler/ARM/invalid-LDRrs-arm.txt
@@ -0,0 +1,4 @@
+# RUN: llvm-mc --disassemble %s -triple=arm-apple-darwin9 |& grep {invalid instruction encoding}
+
+# LDR (register) has encoding Inst{4} = 0.
+0xba 0xae 0x9f 0x57