[ARM] Allow SP in rGPR, starting from ARMv8

Summary:
This patch handles assembly and disassembly, but not codegen, as of yet.

Additionally, it fixes a bug whereby SP and PC as shifted-reg operands
were treated as predictable in ARMv7 Thumb; and it enables the tests
for invalid and unpredictable instructions to run on both ARMv7 and ARMv8.

Reviewers: jmolloy, rengolin

Subscribers: aemerson, rengolin, llvm-commits

Differential Revision: http://reviews.llvm.org/D14141

llvm-svn: 251516

1 files changed, 7 insertions, 2 deletions

diff --git a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index 38cb585edc0..04e4245b633 100644
--- a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -966,8 +966,13 @@ static DecodeStatus DecodetcGPRRegisterClass(MCInst &Inst, unsigned RegNo,
 static DecodeStatus DecoderGPRRegisterClass(MCInst &Inst, unsigned RegNo,
                                    uint64_t Address, const void *Decoder) {
   DecodeStatus S = MCDisassembler::Success;
-  if (RegNo == 13 || RegNo == 15)
+
+  const FeatureBitset &featureBits =
+    ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
+
+  if ((RegNo == 13 && !featureBits[ARM::HasV8Ops]) || RegNo == 15)
     S = MCDisassembler::SoftFail;
+
   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
   return S;
 }
@@ -1127,7 +1132,7 @@ static DecodeStatus DecodeSORegImmOperand(MCInst &Inst, unsigned Val,
   unsigned imm = fieldFromInstruction(Val, 7, 5);
 
   // Register-immediate
-  if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
+  if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
     return MCDisassembler::Fail;
 
   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;