Thumb2 assembly parsing and encoding for LDR pre-indexed w/ writeback.

Adjust encoding of writeback load/store instructions to better reflect the
way the operand types are represented.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139270 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index b66adfc..abe5505 100644
--- a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -158,6 +158,8 @@
   OperandMatchResultTy parseAM3Offset(SmallVectorImpl<MCParsedAsmOperand*>&);
 
   // Asm Match Converter Methods
+  bool cvtLdWriteBackRegT2AddrModeImm8(MCInst &Inst, unsigned Opcode,
+                                  const SmallVectorImpl<MCParsedAsmOperand*> &);
   bool cvtLdWriteBackRegAddrMode2(MCInst &Inst, unsigned Opcode,
                                   const SmallVectorImpl<MCParsedAsmOperand*> &);
   bool cvtLdWriteBackRegAddrModeImm12(MCInst &Inst, unsigned Opcode,
@@ -2398,6 +2400,22 @@
   return MatchOperand_Success;
 }
 
+/// cvtLdWriteBackRegT2AddrModeImm8 - Convert parsed operands to MCInst.
+/// Needed here because the Asm Gen Matcher can't handle properly tied operands
+/// when they refer multiple MIOperands inside a single one.
+bool ARMAsmParser::
+cvtLdWriteBackRegT2AddrModeImm8(MCInst &Inst, unsigned Opcode,
+                         const SmallVectorImpl<MCParsedAsmOperand*> &Operands) {
+  ((ARMOperand*)Operands[2])->addRegOperands(Inst, 1);
+
+  // Create a writeback register dummy placeholder.
+  Inst.addOperand(MCOperand::CreateImm(0));
+
+  ((ARMOperand*)Operands[3])->addMemImm8OffsetOperands(Inst, 2);
+  ((ARMOperand*)Operands[1])->addCondCodeOperands(Inst, 2);
+  return true;
+}
+
 /// cvtLdWriteBackRegAddrMode2 - Convert parsed operands to MCInst.
 /// Needed here because the Asm Gen Matcher can't handle properly tied operands
 /// when they refer multiple MIOperands inside a single one.