ARM Assembler support for DBG instruction.

Add range checking and testing for parsing and encoding of DBG instruction.

llvm-svn: 135102
diff --git a/llvm/lib/Target/ARM/ARMInstrInfo.td b/llvm/lib/Target/ARM/ARMInstrInfo.td
index 050fd98..437f964 100644
--- a/llvm/lib/Target/ARM/ARMInstrInfo.td
+++ b/llvm/lib/Target/ARM/ARMInstrInfo.td
@@ -1283,9 +1283,8 @@
   let Inst{8-0} = 0;
 }
 
-def DBG : AI<(outs), (ins i32imm:$opt), MiscFrm, NoItinerary, "dbg", "\t$opt",
-             [/* For disassembly only; pattern left blank */]>,
-          Requires<[IsARM, HasV7]> {
+def DBG : AI<(outs), (ins imm0_15:$opt), MiscFrm, NoItinerary, "dbg", "\t$opt",
+             []>, Requires<[IsARM, HasV7]> {
   bits<4> opt;
   let Inst{27-4} = 0b001100100000111100001111;
   let Inst{3-0} = opt;