[ARMv8-M] [8/9] Add new system registers to ARMv8-M Baseline/Mainline

[bsmith]

Summary

This patch forms part of the ARMv8-M Baseline/Mainline support, adding support for new system registers in ARMv8-M Baseline/Mainline.

[bsmith]

Rebase patch against latest trunk changes.

[t.p.northover]

One nit here...

lib/Target/ARM/ARMISelDAGToDAG.cpp

3765

Won't this allow "basepri_maxns"? Seems a bit inconsistent with the others.

[bsmith]

lib/Target/ARM/ARMISelDAGToDAG.cpp

3765

It will reconstruct Reg = basepri, Flags = max{_ns,} into Reg = basepri_max, Flags = {ns,}, the call to getMClassRegisterMask afterwards will check whether or not the ns flags are allowed.

[t.p.northover]

lib/Target/ARM/ARMISelDAGToDAG.cpp

3765

But what if the second '_' is skipped? It looks like we'd treat Flags == "max_ns" and Flags == "maxns" equivalently, which seems like an unnecessary quirk.

[bsmith]

lib/Target/ARM/ARMISelDAGToDAG.cpp

3765

Ah, I see what you meant now, I'll fix it.

[bsmith]

Fixup logic handling basepri_max{_ns,} field splitting so as to not allow basepri_maxns.

[t.p.northover]

This looks reasonable now. Thanks for updating the patch.

Tim.

[bsmith]

Thanks, committed as r257884.

lib/Target/ARM/ARMISelDAGToDAG.cpp

return StringSwitch<int>(RegString.lower())
           .Case("iepsr", 0x7)
           .Case("msp", 0x8)
           .Case("psp", 0x9)
           .Case("primask", 0x10)
           .Case("basepri", 0x11)
           .Case("basepri_max", 0x12)
           .Case("faultmask", 0x13)
           .Case("control", 0x14)
+          .Case("msplim", 0x0a)
+          .Case("psplim", 0x0b)
+          .Case("sp", 0x18)
           .Default(-1);
 }
 
 // The flags here are common to those allowed for apsr in the A class cores and
 // those allowed for the special registers in the M class cores. Returns a
 // value representing which flags were present, -1 if invalid.
 static inline int getMClassFlagsMask(StringRef Flags, bool hasDSP) {
   if (Flags.empty())
static int getMClassRegisterMask(StringRef Reg, StringRef Flags, bool IsRead,
   int SYSmvalue = getMClassRegisterSYSmValueMask(Reg);
   if (SYSmvalue == -1)
     return -1;
 
   // basepri, basepri_max and faultmask are only valid for V7m.
   if (!Subtarget->hasV7Ops() && SYSmvalue >= 0x11 && SYSmvalue <= 0x13)
     return -1;
 
+  if (Subtarget->has8MSecExt() && Flags.lower() == "ns") {
+    Flags = "";
+    SYSmvalue |= 0x80;
+  }
+
+  if (!Subtarget->has8MSecExt() &&
+      (SYSmvalue == 0xa || SYSmvalue == 0xb || SYSmvalue > 0x14))
+    return -1;
+
+  if (!Subtarget->hasV8MMainlineOps() &&
+      (SYSmvalue == 0x8a || SYSmvalue == 0x8b || SYSmvalue == 0x91 ||
+       SYSmvalue == 0x93))
+    return -1;
+
   // If it was a read then we won't be expecting flags and so at this point
   // we can return the mask.
   if (IsRead) {
-    assert (Flags.empty() && "Unexpected flags for reading M class register.");
+    if (Flags.empty())
       return SYSmvalue;
+    else
+      return -1;
   }
 
   // We know we are now handling a write so need to get the mask for the flags.
   int Mask = getMClassFlagsMask(Flags, Subtarget->hasDSP());
 
   // Only apsr, iapsr, eapsr, xpsr can have flags. The other register values
   // shouldn't have flags present.
   if ((SYSmvalue < 0x4 && Mask == -1) || (SYSmvalue > 0x4 && !Flags.empty()))
Ops = { getAL(CurDAG, DL), CurDAG->getRegister(0, MVT::i32),
             N->getOperand(0) };
     return CurDAG->getMachineNode(Opcode, DL, MVT::i32, MVT::Other, Ops);
   }
 
   // If the target is M Class then need to validate that the register string
   // is an acceptable value, so check that a mask can be constructed from the
   // string.
   if (Subtarget->isMClass()) {
-    int SYSmValue = getMClassRegisterMask(SpecialReg, "", true, Subtarget);
+    StringRef Flags = "", Reg = SpecialReg;
+    if (Reg.endswith("_ns")) {
+      Flags = "ns";
+      Reg = Reg.drop_back(3);
+    }
+
+    int SYSmValue = getMClassRegisterMask(Reg, Flags, true, Subtarget);
     if (SYSmValue == -1)
       return nullptr;
 
     SDValue Ops[] = { CurDAG->getTargetConstant(SYSmValue, DL, MVT::i32),
                       getAL(CurDAG, DL), CurDAG->getRegister(0, MVT::i32),
                       N->getOperand(0) };
     return CurDAG->getMachineNode(ARM::t2MRS_M, DL, MVT::i32, MVT::Other, Ops);
   }
SDNode *ARMDAGToDAGISel::SelectWriteRegister(SDNode *N){
   StringRef(SpecialReg).split(Fields, '_', 1, false);
   std::string Reg = Fields[0].str();
   StringRef Flags = Fields.size() == 2 ? Fields[1] : "";
 
   // If the target was M Class then need to validate the special register value
   // and retrieve the mask for use in the instruction node.
   if (Subtarget->isMClass()) {
     // basepri_max gets split so need to correct Reg and Flags.
-    if (SpecialReg == "basepri_max") {
-      Reg = SpecialReg;
-      Flags = "";
+    if (Reg == "basepri" && Flags.startswith("max")) {
+      Reg = "basepri_max";
+      Flags = Flags.drop_front(3);
+      if (Flags.startswith("_"))
+        Flags = Flags.drop_front();
     }
     int SYSmValue = getMClassRegisterMask(Reg, Flags, false, Subtarget);
     if (SYSmValue == -1)
       return nullptr;
 
     SDValue Ops[] = { CurDAG->getTargetConstant(SYSmValue, DL, MVT::i32),
                       N->getOperand(2), getAL(CurDAG, DL),
                       CurDAG->getRegister(0, MVT::i32), N->getOperand(0) };

lib/Target/ARM/AsmParser/ARMAsmParser.cpp

bool hasV7Ops() const {
     return getSTI().getFeatureBits()[ARM::HasV7Ops];
   }
   bool hasV8Ops() const {
     return getSTI().getFeatureBits()[ARM::HasV8Ops];
   }
   bool hasV8MBaseline() const {
     return getSTI().getFeatureBits()[ARM::HasV8MBaselineOps];
   }
+  bool hasV8MMainline() const {
+    return getSTI().getFeatureBits()[ARM::HasV8MMainlineOps];
+  }
+  bool has8MSecExt() const {
+    return getSTI().getFeatureBits()[ARM::Feature8MSecExt];
+  }
   bool hasARM() const {
     return !getSTI().getFeatureBits()[ARM::FeatureNoARM];
   }
   bool hasDSP() const {
     return getSTI().getFeatureBits()[ARM::FeatureDSP];
   }
   bool hasD16() const {
     return getSTI().getFeatureBits()[ARM::FeatureD16];
unsigned FlagsVal = StringSwitch<unsigned>(Name)
       .Case("iepsr", 0x807)
       .Case("msp", 0x808)
       .Case("psp", 0x809)
       .Case("primask", 0x810)
       .Case("basepri", 0x811)
       .Case("basepri_max", 0x812)
       .Case("faultmask", 0x813)
       .Case("control", 0x814)
+      .Case("msplim", 0x80a)
+      .Case("psplim", 0x80b)
+      .Case("msp_ns", 0x888)
+      .Case("psp_ns", 0x889)
+      .Case("msplim_ns", 0x88a)
+      .Case("psplim_ns", 0x88b)
+      .Case("primask_ns", 0x890)
+      .Case("basepri_ns", 0x891)
+      .Case("basepri_max_ns", 0x892)
+      .Case("faultmask_ns", 0x893)
+      .Case("control_ns", 0x894)
+      .Case("sp_ns", 0x898)
       .Default(~0U);
 
     if (FlagsVal == ~0U)
       return MatchOperand_NoMatch;
 
     if (!hasDSP() && (FlagsVal & 0x400))
       // The _g and _nzcvqg versions are only valid if the DSP extension is
       // available.
       return MatchOperand_NoMatch;
 
     if (!hasV7Ops() && FlagsVal >= 0x811 && FlagsVal <= 0x813)
       // basepri, basepri_max and faultmask only valid for V7m.
       return MatchOperand_NoMatch;
 
+    if (!has8MSecExt() && (FlagsVal == 0x80a || FlagsVal == 0x80b ||
+                             (FlagsVal > 0x814 && FlagsVal < 0xc00)))
+      return MatchOperand_NoMatch;
+
+    if (!hasV8MMainline() && (FlagsVal == 0x88a || FlagsVal == 0x88b ||
+                              (FlagsVal > 0x890 && FlagsVal <= 0x893)))
+      return MatchOperand_NoMatch;
+
     Parser.Lex(); // Eat identifier token.
     Operands.push_back(ARMOperand::CreateMSRMask(FlagsVal, S));
     return MatchOperand_Success;
   }
 
   // Split spec_reg from flag, example: CPSR_sxf => "CPSR" and "sxf"
   size_t Start = 0, Next = Mask.find('_');
   StringRef Flags = "";

lib/Target/ARM/Disassembler/ARMDisassembler.cpp

case 20: // control
       break;
     case 17: // basepri
     case 18: // basepri_max
     case 19: // faultmask
       if (!(FeatureBits[ARM::HasV7Ops]))
         // Values basepri, basepri_max and faultmask are only valid for v7m.
         return MCDisassembler::Fail;
       break;
+    case 0x8a: // msplim_ns
+    case 0x8b: // psplim_ns
+    case 0x91: // basepri_ns
+    case 0x92: // basepri_max_ns
+    case 0x93: // faultmask_ns
+      if (!(FeatureBits[ARM::HasV8MMainlineOps]))
+        return MCDisassembler::Fail;
+      // fall through
+    case 10:   // msplim
+    case 11:   // psplim
+    case 0x88: // msp_ns
+    case 0x89: // psp_ns
+    case 0x90: // primask_ns
+    case 0x94: // control_ns
+    case 0x98: // sp_ns
+      if (!(FeatureBits[ARM::Feature8MSecExt]))
+        return MCDisassembler::Fail;
+      break;
     default:
       return MCDisassembler::Fail;
     }
 
     if (Inst.getOpcode() == ARM::t2MSR_M) {
       unsigned Mask = fieldFromInstruction(Val, 10, 2);
       if (!(FeatureBits[ARM::HasV7Ops])) {
         // The ARMv6-M MSR bits {11-10} can be only 0b10, other values are

lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp

case 18:
       O << "basepri_max";
       return;
     case 19:
       O << "faultmask";
       return;
     case 20:
       O << "control";
       return;
+    case 10:
+      O << "msplim";
+      return;
+    case 11:
+      O << "psplim";
+      return;
+    case 0x88:
+      O << "msp_ns";
+      return;
+    case 0x89:
+      O << "psp_ns";
+      return;
+    case 0x8a:
+      O << "msplim_ns";
+      return;
+    case 0x8b:
+      O << "psplim_ns";
+      return;
+    case 0x90:
+      O << "primask_ns";
+      return;
+    case 0x91:
+      O << "basepri_ns";
+      return;
+    case 0x92:
+      O << "basepri_max_ns";
+      return;
+    case 0x93:
+      O << "faultmask_ns";
+      return;
+    case 0x94:
+      O << "control_ns";
+      return;
+    case 0x98:
+      O << "sp_ns";
+      return;
     }
   }
 
   // As special cases, CPSR_f, CPSR_s and CPSR_fs prefer printing as
   // APSR_nzcvq, APSR_g and APSRnzcvqg, respectively.
   if (!SpecRegRBit && (Mask == 8 || Mask == 4 || Mask == 12)) {
     O << "APSR_";
     switch (Mask) {

test/CodeGen/ARM/special-reg-v8m-base.ll

+; RUN: not llc < %s -mtriple=thumb-none-eabi -mcpu=cortex-m4 2>&1 | FileCheck %s --check-prefix=V7M
+; RUN: llc < %s -mtriple=thumbv8m.base-none-eabi 2>&1 | FileCheck %s
+
+; V7M: LLVM ERROR: Invalid register name "sp_ns".
+
+define i32 @read_mclass_registers() nounwind {
+entry:
+  ; CHECK-LABEL: read_mclass_registers:
+  ; CHECK:   mrs r0, apsr
+  ; CHECK:   mrs r1, iapsr
+  ; CHECK:   mrs r1, eapsr
+  ; CHECK:   mrs r1, xpsr
+  ; CHECK:   mrs r1, ipsr
+  ; CHECK:   mrs r1, epsr
+  ; CHECK:   mrs r1, iepsr
+  ; CHECK:   mrs r1, msp
+  ; CHECK:   mrs r1, psp
+  ; CHECK:   mrs r1, primask
+  ; CHECK:   mrs r1, control
+  ; CHECK:   mrs r1, msplim
+  ; CHECK:   mrs r1, psplim
+  ; CHECK:   mrs r1, msp_ns
+  ; CHECK:   mrs r1, psp_ns
+  ; CHECK:   mrs r1, primask_ns
+  ; CHECK:   mrs r1, control_ns
+  ; CHECK:   mrs r1, sp_ns
+
+  %0 = call i32 @llvm.read_register.i32(metadata !0)
+  %1 = call i32 @llvm.read_register.i32(metadata !4)
+  %add1 = add i32 %1, %0
+  %2 = call i32 @llvm.read_register.i32(metadata !8)
+  %add2 = add i32 %add1, %2
+  %3 = call i32 @llvm.read_register.i32(metadata !12)
+  %add3 = add i32 %add2, %3
+  %4 = call i32 @llvm.read_register.i32(metadata !16)
+  %add4 = add i32 %add3, %4
+  %5 = call i32 @llvm.read_register.i32(metadata !17)
+  %add5 = add i32 %add4, %5
+  %6 = call i32 @llvm.read_register.i32(metadata !18)
+  %add6 = add i32 %add5, %6
+  %7 = call i32 @llvm.read_register.i32(metadata !19)
+  %add7 = add i32 %add6, %7
+  %8 = call i32 @llvm.read_register.i32(metadata !20)
+  %add8 = add i32 %add7, %8
+  %9 = call i32 @llvm.read_register.i32(metadata !21)
+  %add9 = add i32 %add8, %9
+  %10 = call i32 @llvm.read_register.i32(metadata !25)
+  %add10 = add i32 %add9, %10
+  %11 = call i32 @llvm.read_register.i32(metadata !26)
+  %add11 = add i32 %add10, %11
+  %12 = call i32 @llvm.read_register.i32(metadata !27)
+  %add12 = add i32 %add11, %12
+  %13 = call i32 @llvm.read_register.i32(metadata !28)
+  %add13 = add i32 %add12, %13
+  %14 = call i32 @llvm.read_register.i32(metadata !29)
+  %add14 = add i32 %add13, %14
+  %15 = call i32 @llvm.read_register.i32(metadata !32)
+  %add15 = add i32 %add14, %15
+  %16 = call i32 @llvm.read_register.i32(metadata !35)
+  %add16 = add i32 %add15, %16
+  %17 = call i32 @llvm.read_register.i32(metadata !36)
+  %add17 = add i32 %add16, %17
+  ret i32 %add10
+}
+
+define void @write_mclass_registers(i32 %x) nounwind {
+entry:
+  ; CHECK-LABEL: write_mclass_registers:
+  ; CHECK:   msr apsr, r0
+  ; CHECK:   msr apsr, r0
+  ; CHECK:   msr iapsr, r0
+  ; CHECK:   msr iapsr, r0
+  ; CHECK:   msr eapsr, r0
+  ; CHECK:   msr eapsr, r0
+  ; CHECK:   msr xpsr, r0
+  ; CHECK:   msr xpsr, r0
+  ; CHECK:   msr ipsr, r0
+  ; CHECK:   msr epsr, r0
+  ; CHECK:   msr iepsr, r0
+  ; CHECK:   msr msp, r0
+  ; CHECK:   msr psp, r0
+  ; CHECK:   msr primask, r0
+  ; CHECK:   msr control, r0
+  ; CHECK:   msr msplim, r0
+  ; CHECK:   msr psplim, r0
+  ; CHECK:   msr msp_ns, r0
+  ; CHECK:   msr psp_ns, r0
+  ; CHECK:   msr primask_ns, r0
+  ; CHECK:   msr control_ns, r0
+  ; CHECK:   msr sp_ns, r0
+
+  call void @llvm.write_register.i32(metadata !0, i32 %x)
+  call void @llvm.write_register.i32(metadata !1, i32 %x)
+  call void @llvm.write_register.i32(metadata !4, i32 %x)
+  call void @llvm.write_register.i32(metadata !5, i32 %x)
+  call void @llvm.write_register.i32(metadata !8, i32 %x)
+  call void @llvm.write_register.i32(metadata !9, i32 %x)
+  call void @llvm.write_register.i32(metadata !12, i32 %x)
+  call void @llvm.write_register.i32(metadata !13, i32 %x)
+  call void @llvm.write_register.i32(metadata !16, i32 %x)
+  call void @llvm.write_register.i32(metadata !17, i32 %x)
+  call void @llvm.write_register.i32(metadata !18, i32 %x)
+  call void @llvm.write_register.i32(metadata !19, i32 %x)
+  call void @llvm.write_register.i32(metadata !20, i32 %x)
+  call void @llvm.write_register.i32(metadata !21, i32 %x)
+  call void @llvm.write_register.i32(metadata !25, i32 %x)
+  call void @llvm.write_register.i32(metadata !26, i32 %x)
+  call void @llvm.write_register.i32(metadata !27, i32 %x)
+  call void @llvm.write_register.i32(metadata !28, i32 %x)
+  call void @llvm.write_register.i32(metadata !29, i32 %x)
+  call void @llvm.write_register.i32(metadata !32, i32 %x)
+  call void @llvm.write_register.i32(metadata !35, i32 %x)
+  call void @llvm.write_register.i32(metadata !36, i32 %x)
+  ret void
+}
+
+declare i32 @llvm.read_register.i32(metadata) nounwind
+declare void @llvm.write_register.i32(metadata, i32) nounwind
+
+!0 = !{!"apsr"}
+!1 = !{!"apsr_nzcvq"}
+!4 = !{!"iapsr"}
+!5 = !{!"iapsr_nzcvq"}
+!8 = !{!"eapsr"}
+!9 = !{!"eapsr_nzcvq"}
+!12 = !{!"xpsr"}
+!13 = !{!"xpsr_nzcvq"}
+!16 = !{!"ipsr"}
+!17 = !{!"epsr"}
+!18 = !{!"iepsr"}
+!19 = !{!"msp"}
+!20 = !{!"psp"}
+!21 = !{!"primask"}
+!25 = !{!"control"}
+!26 = !{!"msplim"}
+!27 = !{!"psplim"}
+!28 = !{!"msp_ns"}
+!29 = !{!"psp_ns"}
+!32 = !{!"primask_ns"}
+!35 = !{!"control_ns"}
+!36 = !{!"sp_ns"}
+

test/CodeGen/ARM/special-reg-v8m-main.ll

+; RUN: not llc < %s -mtriple=thumbv8m.base-none-eabi 2>&1 | FileCheck %s --check-prefix=BASELINE
+; RUN: llc < %s -mtriple=thumbv8m.main-none-eabi -mattr=+dsp 2>&1 | FileCheck %s --check-prefix=MAINLINE
+
+; BASELINE: LLVM ERROR: Invalid register name "basepri_max_ns".
+
+define i32 @read_mclass_registers() nounwind {
+entry:
+  ; MAINLINE-LABEL: read_mclass_registers:
+  ; MAINLINE:   mrs r0, apsr
+  ; MAINLINE:   mrs r1, iapsr
+  ; MAINLINE:   mrs r1, eapsr
+  ; MAINLINE:   mrs r1, xpsr
+  ; MAINLINE:   mrs r1, ipsr
+  ; MAINLINE:   mrs r1, epsr
+  ; MAINLINE:   mrs r1, iepsr
+  ; MAINLINE:   mrs r1, msp
+  ; MAINLINE:   mrs r1, psp
+  ; MAINLINE:   mrs r1, primask
+  ; MAINLINE:   mrs r1, basepri
+  ; MAINLINE:   mrs r1, basepri_max
+  ; MAINLINE:   mrs r1, faultmask
+  ; MAINLINE:   mrs r1, control
+  ; MAINLINE:   mrs r1, msplim
+  ; MAINLINE:   mrs r1, psplim
+  ; MAINLINE:   mrs r1, msp_ns
+  ; MAINLINE:   mrs r1, psp_ns
+  ; MAINLINE:   mrs r1, msplim_ns
+  ; MAINLINE:   mrs r1, psplim_ns
+  ; MAINLINE:   mrs r1, primask_ns
+  ; MAINLINE:   mrs r1, basepri_ns
+  ; MAINLINE:   mrs r1, faultmask_ns
+  ; MAINLINE:   mrs r1, control_ns
+  ; MAINLINE:   mrs r1, sp_ns
+  ; MAINLINE:   mrs r1, basepri_max_ns
+
+  %0 = call i32 @llvm.read_register.i32(metadata !0)
+  %1 = call i32 @llvm.read_register.i32(metadata !4)
+  %add1 = add i32 %1, %0
+  %2 = call i32 @llvm.read_register.i32(metadata !8)
+  %add2 = add i32 %add1, %2
+  %3 = call i32 @llvm.read_register.i32(metadata !12)
+  %add3 = add i32 %add2, %3
+  %4 = call i32 @llvm.read_register.i32(metadata !16)
+  %add4 = add i32 %add3, %4
+  %5 = call i32 @llvm.read_register.i32(metadata !17)
+  %add5 = add i32 %add4, %5
+  %6 = call i32 @llvm.read_register.i32(metadata !18)
+  %add6 = add i32 %add5, %6
+  %7 = call i32 @llvm.read_register.i32(metadata !19)
+  %add7 = add i32 %add6, %7
+  %8 = call i32 @llvm.read_register.i32(metadata !20)
+  %add8 = add i32 %add7, %8
+  %9 = call i32 @llvm.read_register.i32(metadata !21)
+  %add9 = add i32 %add8, %9
+  %10 = call i32 @llvm.read_register.i32(metadata !22)
+  %add10 = add i32 %add9, %10
+  %11 = call i32 @llvm.read_register.i32(metadata !23)
+  %add11 = add i32 %add10, %11
+  %12 = call i32 @llvm.read_register.i32(metadata !24)
+  %add12 = add i32 %add11, %12
+  %13 = call i32 @llvm.read_register.i32(metadata !25)
+  %add13 = add i32 %add12, %13
+  %14 = call i32 @llvm.read_register.i32(metadata !26)
+  %add14 = add i32 %add13, %14
+  %15 = call i32 @llvm.read_register.i32(metadata !27)
+  %add15 = add i32 %add14, %15
+  %16 = call i32 @llvm.read_register.i32(metadata !28)
+  %add16 = add i32 %add15, %16
+  %17 = call i32 @llvm.read_register.i32(metadata !29)
+  %add17 = add i32 %add16, %17
+  %18 = call i32 @llvm.read_register.i32(metadata !30)
+  %add18 = add i32 %add17, %18
+  %19 = call i32 @llvm.read_register.i32(metadata !31)
+  %add19 = add i32 %add18, %19
+  %20 = call i32 @llvm.read_register.i32(metadata !32)
+  %add20 = add i32 %add19, %20
+  %21 = call i32 @llvm.read_register.i32(metadata !33)
+  %add21 = add i32 %add20, %21
+  %22 = call i32 @llvm.read_register.i32(metadata !34)
+  %add22 = add i32 %add21, %22
+  %23 = call i32 @llvm.read_register.i32(metadata !35)
+  %add23 = add i32 %add22, %23
+  %24 = call i32 @llvm.read_register.i32(metadata !36)
+  %add24 = add i32 %add23, %24
+  %25 = call i32 @llvm.read_register.i32(metadata !37)
+  %add25 = add i32 %add24, %25
+  ret i32 %add25
+}
+
+define void @write_mclass_registers(i32 %x) nounwind {
+entry:
+  ; MAINLINE-LABEL: write_mclass_registers:
+  ; MAINLINE:   msr apsr_nzcvqg, r0
+  ; MAINLINE:   msr apsr_nzcvq, r0
+  ; MAINLINE:   msr apsr_g, r0
+  ; MAINLINE:   msr apsr_nzcvqg, r0
+  ; MAINLINE:   msr iapsr_nzcvqg, r0
+  ; MAINLINE:   msr iapsr_nzcvq, r0
+  ; MAINLINE:   msr iapsr_g, r0
+  ; MAINLINE:   msr iapsr_nzcvqg, r0
+  ; MAINLINE:   msr eapsr_nzcvqg, r0
+  ; MAINLINE:   msr eapsr_nzcvq, r0
+  ; MAINLINE:   msr eapsr_g, r0
+  ; MAINLINE:   msr eapsr_nzcvqg, r0
+  ; MAINLINE:   msr xpsr_nzcvqg, r0
+  ; MAINLINE:   msr xpsr_nzcvq, r0
+  ; MAINLINE:   msr xpsr_g, r0
+  ; MAINLINE:   msr xpsr_nzcvqg, r0
+  ; MAINLINE:   msr ipsr, r0
+  ; MAINLINE:   msr epsr, r0
+  ; MAINLINE:   msr iepsr, r0
+  ; MAINLINE:   msr msp, r0
+  ; MAINLINE:   msr psp, r0
+  ; MAINLINE:   msr primask, r0
+  ; MAINLINE:   msr basepri, r0
+  ; MAINLINE:   msr basepri_max, r0
+  ; MAINLINE:   msr faultmask, r0
+  ; MAINLINE:   msr control, r0
+  ; MAINLINE:   msr msplim, r0
+  ; MAINLINE:   msr psplim, r0
+  ; MAINLINE:   msr msp_ns, r0
+  ; MAINLINE:   msr psp_ns, r0
+  ; MAINLINE:   msr msplim_ns, r0
+  ; MAINLINE:   msr psplim_ns, r0
+  ; MAINLINE:   msr primask_ns, r0
+  ; MAINLINE:   msr basepri_ns, r0
+  ; MAINLINE:   msr faultmask_ns, r0
+  ; MAINLINE:   msr control_ns, r0
+  ; MAINLINE:   msr sp_ns, r0
+  ; MAINLINE:   msr basepri_max_ns, r0
+
+  call void @llvm.write_register.i32(metadata !0, i32 %x)
+  call void @llvm.write_register.i32(metadata !1, i32 %x)
+  call void @llvm.write_register.i32(metadata !2, i32 %x)
+  call void @llvm.write_register.i32(metadata !3, i32 %x)
+  call void @llvm.write_register.i32(metadata !4, i32 %x)
+  call void @llvm.write_register.i32(metadata !5, i32 %x)
+  call void @llvm.write_register.i32(metadata !6, i32 %x)
+  call void @llvm.write_register.i32(metadata !7, i32 %x)
+  call void @llvm.write_register.i32(metadata !8, i32 %x)
+  call void @llvm.write_register.i32(metadata !9, i32 %x)
+  call void @llvm.write_register.i32(metadata !10, i32 %x)
+  call void @llvm.write_register.i32(metadata !11, i32 %x)
+  call void @llvm.write_register.i32(metadata !12, i32 %x)
+  call void @llvm.write_register.i32(metadata !13, i32 %x)
+  call void @llvm.write_register.i32(metadata !14, i32 %x)
+  call void @llvm.write_register.i32(metadata !15, i32 %x)
+  call void @llvm.write_register.i32(metadata !16, i32 %x)
+  call void @llvm.write_register.i32(metadata !17, i32 %x)
+  call void @llvm.write_register.i32(metadata !18, i32 %x)
+  call void @llvm.write_register.i32(metadata !19, i32 %x)
+  call void @llvm.write_register.i32(metadata !20, i32 %x)
+  call void @llvm.write_register.i32(metadata !21, i32 %x)
+  call void @llvm.write_register.i32(metadata !22, i32 %x)
+  call void @llvm.write_register.i32(metadata !23, i32 %x)
+  call void @llvm.write_register.i32(metadata !24, i32 %x)
+  call void @llvm.write_register.i32(metadata !25, i32 %x)
+  call void @llvm.write_register.i32(metadata !26, i32 %x)
+  call void @llvm.write_register.i32(metadata !27, i32 %x)
+  call void @llvm.write_register.i32(metadata !28, i32 %x)
+  call void @llvm.write_register.i32(metadata !29, i32 %x)
+  call void @llvm.write_register.i32(metadata !30, i32 %x)
+  call void @llvm.write_register.i32(metadata !31, i32 %x)
+  call void @llvm.write_register.i32(metadata !32, i32 %x)
+  call void @llvm.write_register.i32(metadata !33, i32 %x)
+  call void @llvm.write_register.i32(metadata !34, i32 %x)
+  call void @llvm.write_register.i32(metadata !35, i32 %x)
+  call void @llvm.write_register.i32(metadata !36, i32 %x)
+  call void @llvm.write_register.i32(metadata !37, i32 %x)
+  ret void
+}
+
+declare i32 @llvm.read_register.i32(metadata) nounwind
+declare void @llvm.write_register.i32(metadata, i32) nounwind
+
+!0 = !{!"apsr"}
+!1 = !{!"apsr_nzcvq"}
+!2 = !{!"apsr_g"}
+!3 = !{!"apsr_nzcvqg"}
+!4 = !{!"iapsr"}
+!5 = !{!"iapsr_nzcvq"}
+!6 = !{!"iapsr_g"}
+!7 = !{!"iapsr_nzcvqg"}
+!8 = !{!"eapsr"}
+!9 = !{!"eapsr_nzcvq"}
+!10 = !{!"eapsr_g"}
+!11 = !{!"eapsr_nzcvqg"}
+!12 = !{!"xpsr"}
+!13 = !{!"xpsr_nzcvq"}
+!14 = !{!"xpsr_g"}
+!15 = !{!"xpsr_nzcvqg"}
+!16 = !{!"ipsr"}
+!17 = !{!"epsr"}
+!18 = !{!"iepsr"}
+!19 = !{!"msp"}
+!20 = !{!"psp"}
+!21 = !{!"primask"}
+!22 = !{!"basepri"}
+!23 = !{!"basepri_max"}
+!24 = !{!"faultmask"}
+!25 = !{!"control"}
+!26 = !{!"msplim"}
+!27 = !{!"psplim"}
+!28 = !{!"msp_ns"}
+!29 = !{!"psp_ns"}
+!30 = !{!"msplim_ns"}
+!31 = !{!"psplim_ns"}
+!32 = !{!"primask_ns"}
+!33 = !{!"basepri_ns"}
+!34 = !{!"faultmask_ns"}
+!35 = !{!"control_ns"}
+!36 = !{!"sp_ns"}
+!37 = !{!"basepri_max_ns"}
+

test/MC/ARM/thumbv8m.s

 // UNDEF-BASELINE: error: instruction requires: armv8m.main
 // CHECK-MAINLINE: vlldm r5          @ encoding: [0x35,0xec,0x00,0x0a]
 vlldm r5
 
 // UNDEF-BASELINE: error: instruction requires: armv8m.main
 // CHECK-MAINLINE: vlstm r10         @ encoding: [0x2a,0xec,0x00,0x0a]
 vlstm r10
 
+// New SYSm's
+
+MRS r1, MSP_NS
+// CHECK: mrs r1, msp_ns             @ encoding: [0xef,0xf3,0x88,0x81]
+MSR PSP_NS, r2
+// CHECK: msr psp_ns, r2             @ encoding: [0x82,0xf3,0x89,0x88]
+MRS r3, PRIMASK_NS
+// CHECK: mrs r3, primask_ns         @ encoding: [0xef,0xf3,0x90,0x83]
+MSR CONTROL_NS, r4
+// CHECK: msr control_ns, r4         @ encoding: [0x84,0xf3,0x94,0x88]
+MRS r5, SP_NS
+// CHECK: mrs r5, sp_ns              @ encoding: [0xef,0xf3,0x98,0x85]
+MRS r6,MSPLIM
+// CHECK: mrs r6, msplim             @ encoding: [0xef,0xf3,0x0a,0x86]
+MRS r7,PSPLIM
+// CHECK: mrs r7, psplim             @ encoding: [0xef,0xf3,0x0b,0x87]
+MSR MSPLIM,r8
+// CHECK: msr msplim, r8             @ encoding: [0x88,0xf3,0x0a,0x88]
+MSR PSPLIM,r9
+// CHECK: msr psplim, r9             @ encoding: [0x89,0xf3,0x0b,0x88]
+
+MRS r10, MSPLIM_NS
+// CHECK-MAINLINE: mrs r10, msplim_ns    @ encoding: [0xef,0xf3,0x8a,0x8a]
+// UNDEF-BASELINE: error: invalid operand for instruction
+MSR PSPLIM_NS, r11
+// CHECK-MAINLINE: msr psplim_ns, r11    @ encoding: [0x8b,0xf3,0x8b,0x88]
+// UNDEF-BASELINE: error: invalid operand for instruction
+MRS r12, BASEPRI_NS
+// CHECK-MAINLINE: mrs r12, basepri_ns   @ encoding: [0xef,0xf3,0x91,0x8c]
+// UNDEF-BASELINE: error: invalid operand for instruction
+MRS r12, BASEPRI_MAX_NS
+// CHECK-MAINLINE: mrs r12, basepri_max_ns @ encoding: [0xef,0xf3,0x92,0x8c]
+// UNDEF-BASELINE: error: invalid operand for instruction
+MSR FAULTMASK_NS, r14
+// CHECK-MAINLINE: msr faultmask_ns, lr  @ encoding: [0x8e,0xf3,0x93,0x88]
+// UNDEF-BASELINE: error: invalid operand for instruction
 
 // Invalid operand tests
 // UNDEF: error: invalid operand for instruction
 sg #0
 // UNDEF: error: invalid operand for instruction
 sg r0
 // UNDEF: error: invalid operand for instruction
 bxns r0, r1

test/MC/Disassembler/ARM/thumb2-v8m.txt

+# RUN: llvm-mc -triple=thumbv8m.base -disassemble < %s 2>%t | FileCheck %s
+# RUN: FileCheck < %t %s --check-prefix=CHECK-STDERR
+# RUN: llvm-mc -triple=thumbv8m.main -disassemble < %s | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-MAINLINE
+
+0xef 0xf3 0x0a 0x83
+# CHECK:          mrs      r3, msplim
+0xef 0xf3 0x0b 0x84
+# CHECK:          mrs      r4, psplim
+0x8b 0xf3 0x0a 0x88
+# CHECK:          msr      msplim, r11
+0x8c 0xf3 0x0b 0x88
+# CHECK:          msr      psplim, r12
+
+0xef 0xf3 0x90 0x86
+# CHECK:          mrs      r6, primask_ns
+0x88 0xf3 0x98 0x88
+# CHECK:          msr      sp_ns, r8
+
+0xef 0xf3 0x8a 0x85
+# CHECK-STDERR: warning: invalid instruction encoding
+# CHECK-MAINLINE: mrs      r5, msplim_ns
+0x87 0xf3 0x93 0x88
+# CHECK-STDERR: warning: invalid instruction encoding
+# CHECK-MAINLINE: msr      faultmask_ns, r7
+