[llvm][arm] add T1 and T2 assembly options for vlldm and vlstm

Re-land 634b0243b8f7acc85af4f16b70e91d86ded4dc83.

T1 allow for an optional registers list,
the register list must be {d0-d15}.
T2 define a mandatory register list,
the register list must be {d0-d31}.

The requirements for T1/T2 are as follows:
                T1              T2
Require:        v8-M.Main,      v8.1-M.Main,
                secure state    secure state
16 D Regs       valid           valid
32 D Regs       UNDEFINED       valid
No D Regs       NOP             NOP

1 files changed, 23 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index 604f22d..705f3cbc 100644
--- a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -700,6 +700,9 @@ DecodeMVEOverlappingLongShift(MCInst &Inst, unsigned Insn, uint64_t Address,
 static DecodeStatus DecodeT2AddSubSPImm(MCInst &Inst, unsigned Insn,
                                         uint64_t Address,
                                         const MCDisassembler *Decoder);
+static DecodeStatus DecodeLazyLoadStoreMul(MCInst &Inst, unsigned Insn,
+                                           uint64_t Address,
+                                           const MCDisassembler *Decoder);
 
 #include "ARMGenDisassemblerTables.inc"
 
@@ -7030,3 +7033,23 @@ static DecodeStatus DecodeT2AddSubSPImm(MCInst &Inst, unsigned Insn,
 
   return DS;
 }
+
+static DecodeStatus DecodeLazyLoadStoreMul(MCInst &Inst, unsigned Insn,
+                                           uint64_t Address,
+                                           const MCDisassembler *Decoder) {
+  DecodeStatus S = MCDisassembler::Success;
+
+  const unsigned Rn = fieldFromInstruction(Insn, 16, 4);
+  // Adding Rn, holding memory location to save/load to/from, the only argument
+  // that is being encoded.
+  // '$Rn' in the assembly.
+  if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
+    return MCDisassembler::Fail;
+  // An optional predicate, '$p' in the assembly.
+  DecodePredicateOperand(Inst, ARMCC::AL, Address, Decoder);
+  // An immediate that represents a floating point registers list. '$regs' in
+  // the assembly.
+  Inst.addOperand(MCOperand::createImm(0)); // Arbitrary value, has no effect.
+
+  return S;
+}