[mips][mips16] Fix machine verifier errors about incorrect register classes on load/stores.

[dsanders]

Summary

[ls][bh] and [ls][bh]u cannot use sp-relative addresses and must therefore
lower frameindex nodes such that there is a copy to a CPU16Regs register. This
is now done consistently using a separate addressing mode that does not
permit frameindex nodes.

As part of this I've had to remove an optimization that reduced the number of
instructions needed to work around the lack of sp-relative addresses on [ls][bh]
and [ls][bh]u. This optimization used one of the eight CPU16Regs registers as
a copy of the stack pointer and it's implementation was the root cause of many
of the register vs register class mismatches.

lw/sw can use sp-relative addresses but we ought to ensure that we use the
correct version of lw/sw internally for things like IAS. This is not currently
the case and this change does not fix this. However, this change does clean it
up sufficiently well to fix the machine verifier failures.

Also removed irrelevant functions from stchar.ll.

[dsanders]

Fix MIR test case.

[dsanders]

ping

[sdardis]

LGTM.

[dsanders]

Refresh before commit

lib/Target/Mips/Mips16ISelDAGToDAG.h

 public:
   explicit Mips16DAGToDAGISel(MipsTargetMachine &TM) : MipsDAGToDAGISel(TM) {}
 
 private:
   std::pair<SDNode *, SDNode *> selectMULT(SDNode *N, unsigned Opc,
                                            const SDLoc &DL, EVT Ty, bool HasLo,
                                            bool HasHi);
 
-  SDValue getMips16SPAliasReg();
-
   bool runOnMachineFunction(MachineFunction &MF) override;
 
-  void getMips16SPRefReg(SDNode *Parent, SDValue &AliasReg);
-
-  bool selectAddr16(SDNode *Parent, SDValue N, SDValue &Base, SDValue &Offset,
-                    SDValue &Alias) override;
+  bool selectAddr(bool SPAllowed, SDValue Addr, SDValue &Base,
+                  SDValue &Offset);
+  bool selectAddr16(SDValue Addr, SDValue &Base,
+                    SDValue &Offset) override;
+  bool selectAddr16SP(SDValue Addr, SDValue &Base,
+                      SDValue &Offset) override;
 
   bool trySelect(SDNode *Node) override;
 
   void processFunctionAfterISel(MachineFunction &MF) override;
 
   // Insert instructions to initialize the global base register in the
   // first MBB of the function.
   void initGlobalBaseReg(MachineFunction &MF);
 
   void initMips16SPAliasReg(MachineFunction &MF);
 };
 
 FunctionPass *createMips16ISelDag(MipsTargetMachine &TM);
 }
 
 #endif

lib/Target/Mips/Mips16ISelDAGToDAG.cpp

BuildMI(MBB, I, DL, TII.get(Mips::GotPrologue16), V0)
       .addExternalSymbol("_gp_disp", MipsII::MO_ABS_LO);
 
   BuildMI(MBB, I, DL, TII.get(Mips::SllX16), V2).addReg(V0).addImm(16);
   BuildMI(MBB, I, DL, TII.get(Mips::AdduRxRyRz16), GlobalBaseReg)
       .addReg(V1)
       .addReg(V2);
 }
 
-// Insert instructions to initialize the Mips16 SP Alias register in the
-// first MBB of the function.
-//
-void Mips16DAGToDAGISel::initMips16SPAliasReg(MachineFunction &MF) {
-  MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
-
-  if (!MipsFI->mips16SPAliasRegSet())
-    return;
-
-  MachineBasicBlock &MBB = MF.front();
-  MachineBasicBlock::iterator I = MBB.begin();
-  const TargetInstrInfo &TII = *Subtarget->getInstrInfo();
-  DebugLoc DL = I != MBB.end() ? I->getDebugLoc() : DebugLoc();
-  unsigned Mips16SPAliasReg = MipsFI->getMips16SPAliasReg();
-
-  BuildMI(MBB, I, DL, TII.get(Mips::MoveR3216), Mips16SPAliasReg)
-      .addReg(Mips::SP);
-}
-
 void Mips16DAGToDAGISel::processFunctionAfterISel(MachineFunction &MF) {
   initGlobalBaseReg(MF);
-  initMips16SPAliasReg(MF);
-}
-
-/// getMips16SPAliasReg - Output the instructions required to put the
-/// SP into a Mips16 accessible aliased register.
-SDValue Mips16DAGToDAGISel::getMips16SPAliasReg() {
-  unsigned Mips16SPAliasReg =
-      MF->getInfo<MipsFunctionInfo>()->getMips16SPAliasReg();
-  auto PtrVT = getTargetLowering()->getPointerTy(CurDAG->getDataLayout());
-  return CurDAG->getRegister(Mips16SPAliasReg, PtrVT);
-}
-
-void Mips16DAGToDAGISel::getMips16SPRefReg(SDNode *Parent, SDValue &AliasReg) {
-  auto PtrVT = getTargetLowering()->getPointerTy(CurDAG->getDataLayout());
-  SDValue AliasFPReg = CurDAG->getRegister(Mips::S0, PtrVT);
-  if (Parent) {
-    switch (Parent->getOpcode()) {
-    case ISD::LOAD: {
-      LoadSDNode *SD = dyn_cast<LoadSDNode>(Parent);
-      switch (SD->getMemoryVT().getSizeInBits()) {
-      case 8:
-      case 16:
-        AliasReg = Subtarget->getFrameLowering()->hasFP(*MF)
-                       ? AliasFPReg
-                       : getMips16SPAliasReg();
-        return;
-      }
-      break;
-    }
-    case ISD::STORE: {
-      StoreSDNode *SD = dyn_cast<StoreSDNode>(Parent);
-      switch (SD->getMemoryVT().getSizeInBits()) {
-      case 8:
-      case 16:
-        AliasReg = Subtarget->getFrameLowering()->hasFP(*MF)
-                       ? AliasFPReg
-                       : getMips16SPAliasReg();
-        return;
-      }
-      break;
-    }
-    }
-  }
-  AliasReg = CurDAG->getRegister(Mips::SP, PtrVT);
-  return;
 }
 
-bool Mips16DAGToDAGISel::selectAddr16(SDNode *Parent, SDValue Addr,
-                                      SDValue &Base, SDValue &Offset,
-                                      SDValue &Alias) {
+bool Mips16DAGToDAGISel::selectAddr(bool SPAllowed, SDValue Addr, SDValue &Base,
+                                    SDValue &Offset) {
   SDLoc DL(Addr);
   EVT ValTy = Addr.getValueType();
 
-  Alias = CurDAG->getTargetConstant(0, DL, ValTy);
-
   // if Address is FI, get the TargetFrameIndex.
+  if (SPAllowed) {
     if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>(Addr)) {
       Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), ValTy);
       Offset = CurDAG->getTargetConstant(0, DL, ValTy);
-    getMips16SPRefReg(Parent, Alias);
       return true;
     }
+  }
   // on PIC code Load GA
   if (Addr.getOpcode() == MipsISD::Wrapper) {
     Base = Addr.getOperand(0);
     Offset = Addr.getOperand(1);
     return true;
   }
   if (TM.getRelocationModel() != Reloc::PIC_) {
     if ((Addr.getOpcode() == ISD::TargetExternalSymbol ||
          Addr.getOpcode() == ISD::TargetGlobalAddress))
       return false;
   }
   // Addresses of the form FI+const or FI|const
   if (CurDAG->isBaseWithConstantOffset(Addr)) {
     ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1));
     if (isInt<16>(CN->getSExtValue())) {
-
       // If the first operand is a FI, get the TargetFI Node
+      if (SPAllowed) {
         if (FrameIndexSDNode *FIN =
                 dyn_cast<FrameIndexSDNode>(Addr.getOperand(0))) {
           Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), ValTy);
-        getMips16SPRefReg(Parent, Alias);
-      } else
-        Base = Addr.getOperand(0);
+          Offset = CurDAG->getTargetConstant(CN->getZExtValue(), DL, ValTy);
+          return true;
+        }
+      }
 
+      Base = Addr.getOperand(0);
       Offset = CurDAG->getTargetConstant(CN->getZExtValue(), DL, ValTy);
       return true;
     }
   }
   // Operand is a result from an ADD.
   if (Addr.getOpcode() == ISD::ADD) {
     // When loading from constant pools, load the lower address part in
     // the instruction itself. Example, instead of:
     //  lui $2, %hi($CPI1_0)
     //  addiu $2, $2, %lo($CPI1_0)
     //  lwc1 $f0, 0($2)
     // Generate:
     //  lui $2, %hi($CPI1_0)
     //  lwc1 $f0, %lo($CPI1_0)($2)
     if (Addr.getOperand(1).getOpcode() == MipsISD::Lo ||
         Addr.getOperand(1).getOpcode() == MipsISD::GPRel) {
       SDValue Opnd0 = Addr.getOperand(1).getOperand(0);
       if (isa<ConstantPoolSDNode>(Opnd0) || isa<GlobalAddressSDNode>(Opnd0) ||
           isa<JumpTableSDNode>(Opnd0)) {
         Base = Addr.getOperand(0);
         Offset = Opnd0;
         return true;
       }
     }
-
-    // If an indexed floating point load/store can be emitted, return false.
-    const LSBaseSDNode *LS = dyn_cast<LSBaseSDNode>(Parent);
-
-    if (LS) {
-      if (LS->getMemoryVT() == MVT::f32 && Subtarget->hasMips4_32r2())
-        return false;
-      if (LS->getMemoryVT() == MVT::f64 && Subtarget->hasMips4_32r2())
-        return false;
-    }
   }
   Base = Addr;
   Offset = CurDAG->getTargetConstant(0, DL, ValTy);
   return true;
 }
 
+bool Mips16DAGToDAGISel::selectAddr16(SDValue Addr, SDValue &Base,
+                                      SDValue &Offset) {
+  return selectAddr(false, Addr, Base, Offset);
+}
+
+bool Mips16DAGToDAGISel::selectAddr16SP(SDValue Addr, SDValue &Base,
+                                        SDValue &Offset) {
+  return selectAddr(true, Addr, Base, Offset);
+}
+
 /// Select instructions not customized! Used for
 /// expanded, promoted and normal instructions
 bool Mips16DAGToDAGISel::trySelect(SDNode *Node) {
   unsigned Opcode = Node->getOpcode();
   SDLoc DL(Node);
 
   ///
   // Instruction Selection not handled by the auto-generated

lib/Target/Mips/Mips16InstrInfo.td

 //===- Mips16InstrInfo.td - Target Description for Mips16  -*- tablegen -*-=//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file describes Mips16 instructions.
 //
 //===----------------------------------------------------------------------===//
 //
 //
 // Mips Address
 //
-def addr16 :
-  ComplexPattern<iPTR, 3, "selectAddr16", [frameindex], [SDNPWantParent]>;
+def addr16 : ComplexPattern<iPTR, 2, "selectAddr16", [frameindex]>;
+def addr16sp : ComplexPattern<iPTR, 2, "selectAddr16SP", [frameindex]>;
 
 //
 // Address operand
 def mem16 : Operand<i32> {
   let PrintMethod = "printMemOperand";
-  let MIOperandInfo = (ops CPU16Regs, simm16, CPU16RegsPlusSP);
+  let MIOperandInfo = (ops CPU16Regs, simm16);
+  let EncoderMethod = "getMemEncoding";
+}
+
+def mem16sp : Operand<i32> {
+  let PrintMethod = "printMemOperand";
+  // This should be CPUSPReg but the MIPS16 subtarget isn't good enough at
+  // keeping the sp-relative load and the other varieties separate at the
+  // moment. This lie fixes the problem sufficiently well to fix the errors
+  // emitted by -verify-machineinstrs and the output ends up correct as long
+  // as we use an external assembler (which is already a requirement for MIPS16
+  // for several other reasons).
+  let MIOperandInfo = (ops CPU16RegsPlusSP, simm16);
   let EncoderMethod = "getMemEncoding";
 }
 
 def mem16_ea : Operand<i32> {
   let PrintMethod = "printMemOperandEA";
   let MIOperandInfo = (ops CPU16RegsPlusSP, simm16);
   let EncoderMethod = "getMemEncoding";
 }

 
 class FEXT_2RI16_ins<bits<5> _op, string asmstr,
                      InstrItinClass itin>:
   FEXT_RI16<_op, (outs CPU16Regs:$rx), (ins CPU16Regs:$rx_, simm16:$imm),
             !strconcat(asmstr, "\t$rx, $imm"), [], itin> {
   let Constraints = "$rx_ = $rx";
 }
 
-
-// this has an explicit sp argument that we ignore to work around a problem
-// in the compiler
-class FEXT_RI16_SP_explicit_ins<bits<5> _op, string asmstr,
-                                InstrItinClass itin>:
-  FEXT_RI16<_op, (outs CPU16Regs:$rx), (ins CPUSPReg:$ry, simm16:$imm),
-            !strconcat(asmstr, "\t$rx, $imm ( $ry ); "), [], itin>;
-
-class FEXT_RI16_SP_Store_explicit_ins<bits<5> _op, string asmstr,
-                                InstrItinClass itin>:
-  FEXT_RI16<_op, (outs), (ins  CPU16Regs:$rx, CPUSPReg:$ry, simm16:$imm),
-            !strconcat(asmstr, "\t$rx, $imm ( $ry ); "), [], itin>;
-
 //
 // EXT-RRI instruction format
 //
 
 class FEXT_RRI16_mem_ins<bits<5> op, string asmstr, Operand MemOpnd,
                          InstrItinClass itin>:
   FEXT_RRI16<op, (outs CPU16Regs:$ry), (ins  MemOpnd:$addr),
              !strconcat(asmstr, "\t$ry, $addr"), [], itin>;

 def LwRxRyOffMemX16: FEXT_RRI16_mem_ins<0b10011, "lw", mem16, II_LW>, MayLoad{
   let isCodeGenOnly = 1;
 }
 
 // Format: LW rx, offset(sp) MIPS16e
 // Purpose: Load Word (SP-Relative, Extended)
 // To load an SP-relative word from memory as a signed value.
 //
-def LwRxSpImmX16: FEXT_RI16_SP_explicit_ins<0b10010, "lw", II_LW>, MayLoad{
-  let Uses = [SP];
-}
+def LwRxSpImmX16: FEXT_RRI16_mem_ins<0b10010, "lw", mem16sp, II_LW>, MayLoad;
 
 def LwRxPcTcp16: FRI16_TCP_ins<0b10110, "lw", II_LW>, MayLoad;
 
 def LwRxPcTcpX16: FEXT_RI16_TCP_ins<0b10110, "lw", II_LW>, MayLoad;
 //
 // Format: MOVE r32, rz MIPS16e
 // Purpose: Move
 // To move the contents of a GPR to a GPR.

 //
 def SubuRxRyRz16: FRRR16_ins<0b11, "subu", IIM16Alu>, ArithLogic16Defs<0>;
 
 //
 // Format: SW ry, offset(rx) MIPS16e
 // Purpose: Store Word (Extended)
 // To store a word to memory.
 //
-def SwRxRyOffMemX16:
-  FEXT_RRI16_mem2_ins<0b11011, "sw", mem16, II_SW>, MayStore;
+def SwRxRyOffMemX16: FEXT_RRI16_mem2_ins<0b11011, "sw", mem16, II_SW>, MayStore;
 
 //
 // Format: SW rx, offset(sp) MIPS16e
 // Purpose: Store Word rx (SP-Relative)
 // To store an SP-relative word to memory.
 //
-def SwRxSpImmX16: FEXT_RI16_SP_Store_explicit_ins
-  <0b11010, "sw", II_SW>, MayStore;
+def SwRxSpImmX16: FEXT_RRI16_mem2_ins<0b11010, "sw", mem16sp, II_SW>, MayStore;
 
 //
 //
 // Format: XOR rx, ry MIPS16e
 // Purpose: Xor
 // To do a bitwise logical XOR.
 //
 def XorRxRxRy16: FRxRxRy16_ins<0b01110, "xor", IIM16Alu>, ArithLogic16Defs<1>;

 class shift_rotate_reg16_pat<SDNode OpNode, Instruction I> :
   Mips16Pat<(OpNode CPU16Regs:$r, CPU16Regs:$ra),
             (I CPU16Regs:$r, CPU16Regs:$ra)>;
 
 def: shift_rotate_reg16_pat<shl, SllvRxRy16>;
 def: shift_rotate_reg16_pat<sra, SravRxRy16>;
 def: shift_rotate_reg16_pat<srl, SrlvRxRy16>;
 
-class LoadM16_pat<PatFrag OpNode, Instruction I> :
-  Mips16Pat<(OpNode addr16:$addr), (I addr16:$addr)>;
+class LoadM16_pat<PatFrag OpNode, Instruction I, ComplexPattern Addr> :
+  Mips16Pat<(OpNode Addr:$addr), (I Addr:$addr)>;
 
-def: LoadM16_pat<sextloadi8, LbRxRyOffMemX16>;
-def: LoadM16_pat<zextloadi8, LbuRxRyOffMemX16>;
-def: LoadM16_pat<sextloadi16, LhRxRyOffMemX16>;
-def: LoadM16_pat<zextloadi16, LhuRxRyOffMemX16>;
-def: LoadM16_pat<load, LwRxRyOffMemX16>;
-
-class StoreM16_pat<PatFrag OpNode, Instruction I> :
-  Mips16Pat<(OpNode CPU16Regs:$r, addr16:$addr),
-            (I CPU16Regs:$r, addr16:$addr)>;
-
-def: StoreM16_pat<truncstorei8, SbRxRyOffMemX16>;
-def: StoreM16_pat<truncstorei16, ShRxRyOffMemX16>;
-def: StoreM16_pat<store, SwRxRyOffMemX16>;
+def: LoadM16_pat<sextloadi8, LbRxRyOffMemX16, addr16>;
+def: LoadM16_pat<zextloadi8, LbuRxRyOffMemX16, addr16>;
+def: LoadM16_pat<sextloadi16, LhRxRyOffMemX16, addr16>;
+def: LoadM16_pat<zextloadi16, LhuRxRyOffMemX16, addr16>;
+def: LoadM16_pat<load, LwRxSpImmX16, addr16sp>;
+
+class StoreM16_pat<PatFrag OpNode, Instruction I, ComplexPattern Addr> :
+  Mips16Pat<(OpNode CPU16Regs:$r, Addr:$addr), (I CPU16Regs:$r, Addr:$addr)>;
+
+def: StoreM16_pat<truncstorei8, SbRxRyOffMemX16, addr16>;
+def: StoreM16_pat<truncstorei16, ShRxRyOffMemX16, addr16>;
+def: StoreM16_pat<store, SwRxSpImmX16, addr16sp>;
 
 // Unconditional branch
 class UncondBranch16_pat<SDNode OpNode, Instruction I>:
   Mips16Pat<(OpNode bb:$imm16), (I bb:$imm16)> {
     let Predicates = [InMips16Mode];
   }
 
 def : Mips16Pat<(MipsJmpLink (i32 tglobaladdr:$dst)),
class SetCC_R16<PatFrag cond_op, Instruction I>:
   Mips16Pat<(cond_op CPU16Regs:$rx, CPU16Regs:$ry),
             (I CPU16Regs:$rx, CPU16Regs:$ry)>;
 
 class SetCC_I16<PatFrag cond_op, PatLeaf imm_type, Instruction I>:
   Mips16Pat<(cond_op CPU16Regs:$rx, imm_type:$imm16),
             (I CPU16Regs:$rx, imm_type:$imm16)>;
 
 
-def: Mips16Pat<(i32  addr16:$addr),
-               (AddiuRxRyOffMemX16  addr16:$addr)>;
+def: Mips16Pat<(i32 addr16sp:$addr), (AddiuRxRyOffMemX16 addr16sp:$addr)>;
 
 
 // Large (>16 bit) immediate loads
 def : Mips16Pat<(i32 imm:$imm), (LwConstant32 imm:$imm, -1)>;
 
 // Carry MipsPatterns
 def : Mips16Pat<(subc CPU16Regs:$lhs, CPU16Regs:$rhs),
                 (SubuRxRyRz16 CPU16Regs:$lhs, CPU16Regs:$rhs)>;

lib/Target/Mips/MipsISelDAGToDAG.h

private:
 
   virtual bool selectIntAddrLSL2MM(SDValue Addr, SDValue &Base,
                                    SDValue &Offset) const;
 
   /// Match addr+simm10 and addr
   virtual bool selectIntAddrMSA(SDValue Addr, SDValue &Base,
                                 SDValue &Offset) const;
 
-  virtual bool selectAddr16(SDNode *Parent, SDValue N, SDValue &Base,
-                            SDValue &Offset, SDValue &Alias);
+  virtual bool selectAddr16(SDValue Addr, SDValue &Base, SDValue &Offset);
+  virtual bool selectAddr16SP(SDValue Addr, SDValue &Base, SDValue &Offset);
 
   /// \brief Select constant vector splats.
   virtual bool selectVSplat(SDNode *N, APInt &Imm,
                             unsigned MinSizeInBits) const;
   /// \brief Select constant vector splats whose value fits in a uimm1.
   virtual bool selectVSplatUimm1(SDValue N, SDValue &Imm) const;
   /// \brief Select constant vector splats whose value fits in a uimm2.
   virtual bool selectVSplatUimm2(SDValue N, SDValue &Imm) const;

lib/Target/Mips/MipsISelDAGToDAG.cpp

 }
 
 bool MipsDAGToDAGISel::selectIntAddrMSA(SDValue Addr, SDValue &Base,
                                         SDValue &Offset) const {
   llvm_unreachable("Unimplemented function.");
   return false;
 }
 
-bool MipsDAGToDAGISel::selectAddr16(SDNode *Parent, SDValue N, SDValue &Base,
-                                    SDValue &Offset, SDValue &Alias) {
+bool MipsDAGToDAGISel::selectAddr16(SDValue Addr, SDValue &Base,
+                                    SDValue &Offset) {
+  llvm_unreachable("Unimplemented function.");
+  return false;
+}
+
+bool MipsDAGToDAGISel::selectAddr16SP(SDValue Addr, SDValue &Base,
+                                      SDValue &Offset) {
   llvm_unreachable("Unimplemented function.");
   return false;
 }
 
 bool MipsDAGToDAGISel::selectVSplat(SDNode *N, APInt &Imm,
                                     unsigned MinSizeInBits) const {
   llvm_unreachable("Unimplemented function.");
   return false;

lib/Target/Mips/MipsMachineFunction.h

 
 namespace llvm {
 
 /// MipsFunctionInfo - This class is derived from MachineFunction private
 /// Mips target-specific information for each MachineFunction.
 class MipsFunctionInfo : public MachineFunctionInfo {
 public:
   MipsFunctionInfo(MachineFunction &MF)
-      : MF(MF), SRetReturnReg(0), GlobalBaseReg(0), Mips16SPAliasReg(0),
-        VarArgsFrameIndex(0), CallsEhReturn(false), IsISR(false), SaveS2(false),
+      : MF(MF), SRetReturnReg(0), GlobalBaseReg(0), VarArgsFrameIndex(0),
+        CallsEhReturn(false), IsISR(false), SaveS2(false),
         MoveF64ViaSpillFI(-1) {}
 
   ~MipsFunctionInfo();
 
   unsigned getSRetReturnReg() const { return SRetReturnReg; }
   void setSRetReturnReg(unsigned Reg) { SRetReturnReg = Reg; }
 
   bool globalBaseRegSet() const;
   unsigned getGlobalBaseReg();
 
-  bool mips16SPAliasRegSet() const;
-  unsigned getMips16SPAliasReg();
-
   int getVarArgsFrameIndex() const { return VarArgsFrameIndex; }
   void setVarArgsFrameIndex(int Index) { VarArgsFrameIndex = Index; }
 
   bool hasByvalArg() const { return HasByvalArg; }
   void setFormalArgInfo(unsigned Size, bool HasByval) {
     IncomingArgSize = Size;
     HasByvalArg = HasByval;
   }
private:
   /// holds the virtual register into which the sret argument is passed.
   unsigned SRetReturnReg;
 
   /// GlobalBaseReg - keeps track of the virtual register initialized for
   /// use as the global base register. This is used for PIC in some PIC
   /// relocation models.
   unsigned GlobalBaseReg;
 
-  /// Mips16SPAliasReg - keeps track of the virtual register initialized for
-  /// use as an alias for SP for use in load/store of halfword/byte from/to
-  /// the stack
-  unsigned Mips16SPAliasReg;
-
   /// VarArgsFrameIndex - FrameIndex for start of varargs area.
   int VarArgsFrameIndex;
 
   /// True if function has a byval argument.
   bool HasByvalArg;
 
   /// Size of incoming argument area.
   unsigned IncomingArgSize;

lib/Target/Mips/MipsMachineFunction.cpp

const TargetRegisterClass *RC =
                 : static_cast<const MipsTargetMachine &>(MF.getTarget())
                           .getABI()
                           .IsN64()
                       ? &Mips::GPR64RegClass
                       : &Mips::GPR32RegClass;
   return GlobalBaseReg = MF.getRegInfo().createVirtualRegister(RC);
 }
 
-bool MipsFunctionInfo::mips16SPAliasRegSet() const {
-  return Mips16SPAliasReg;
-}
-unsigned MipsFunctionInfo::getMips16SPAliasReg() {
-  // Return if it has already been initialized.
-  if (Mips16SPAliasReg)
-    return Mips16SPAliasReg;
-
-  const TargetRegisterClass *RC = &Mips::CPU16RegsRegClass;
-  return Mips16SPAliasReg = MF.getRegInfo().createVirtualRegister(RC);
-}
-
 void MipsFunctionInfo::createEhDataRegsFI() {
   for (int I = 0; I < 4; ++I) {
     const TargetRegisterClass *RC =
         static_cast<const MipsTargetMachine &>(MF.getTarget()).getABI().IsN64()
             ? &Mips::GPR64RegClass
             : &Mips::GPR32RegClass;
 
     EhDataRegFI[I] = MF.getFrameInfo()->CreateStackObject(RC->getSize(),

test/CodeGen/MIR/Mips/memory-operands.mir

bb.0.entry:
 
     Save16 %ra, 24, implicit-def %sp, implicit %sp
     CFI_INSTRUCTION .cfi_def_cfa_offset 24
     CFI_INSTRUCTION .cfi_offset %ra_64, -4
     %v0, %v1 = GotPrologue16 $_gp_disp, $_gp_disp
     %v0 = SllX16 killed %v0, 16
     %v0 = AdduRxRyRz16 killed %v1, killed %v0
   ; CHECK-LABEL: name: test
-  ; CHECK: %v1 = LwRxRyOffMemX16 %v0, @foo, 0 :: (load 4 from call-entry @foo)
-    %v1 = LwRxRyOffMemX16 %v0, @foo, 0 :: (load 4 from call-entry @foo)
+  ; CHECK: %v1 = LwRxRyOffMemX16 %v0, @foo :: (load 4 from call-entry @foo)
+    %v1 = LwRxRyOffMemX16 %v0, @foo :: (load 4 from call-entry @foo)
     %t9 = COPY %v1
     %gp = COPY killed %v0
     JumpLinkReg16 killed %v1, csr_o32, implicit-def %ra, implicit killed %t9, implicit %a0, implicit killed %gp, implicit-def %sp, implicit-def dead %v0
     %v0 = LiRxImmX16 0
     %ra = Restore16 24, implicit-def %sp, implicit %sp
     RetRA16 implicit %v0
 ...
 ---
bb.0.entry:
     SaveX16 %s0, %ra, %s2, 32, implicit-def %sp, implicit %sp
     CFI_INSTRUCTION .cfi_def_cfa_offset 32
     CFI_INSTRUCTION .cfi_offset %ra_64, -4
     CFI_INSTRUCTION .cfi_offset %s2_64, -8
     CFI_INSTRUCTION .cfi_offset %s0_64, -12
     %v0, %v1 = GotPrologue16 $_gp_disp, $_gp_disp
     %v0 = SllX16 killed %v0, 16
     %s0 = AdduRxRyRz16 killed %v1, killed %v0
-    %v0 = LwRxRyOffMemX16 %s0, @g, 0 :: (load 4 from call-entry @g)
+    %v0 = LwRxRyOffMemX16 %s0, @g :: (load 4 from call-entry @g)
   ; CHECK-LABEL: test2
-  ; CHECK: %v1 = LwRxRyOffMemX16 %s0, $__mips16_call_stub_sf_0, 0 :: (load 4 from call-entry $__mips16_call_stub_sf_0)
-    %v1 = LwRxRyOffMemX16 %s0, $__mips16_call_stub_sf_0, 0 :: (load 4 from call-entry $__mips16_call_stub_sf_0)
+  ; CHECK: %v1 = LwRxRyOffMemX16 %s0, $__mips16_call_stub_sf_0 :: (load 4 from call-entry $__mips16_call_stub_sf_0)
+    %v1 = LwRxRyOffMemX16 %s0, $__mips16_call_stub_sf_0 :: (load 4 from call-entry $__mips16_call_stub_sf_0)
     %gp = COPY %s0
     JumpLinkReg16 killed %v1, csr_o32, implicit-def %ra, implicit %v0, implicit killed %gp, implicit-def %sp, implicit-def %v0
-    %v1 = LwRxRyOffMemX16 %s0, @__mips16_ret_sf, 0 :: (load 4 from call-entry @__mips16_ret_sf)
+    %v1 = LwRxRyOffMemX16 %s0, @__mips16_ret_sf :: (load 4 from call-entry @__mips16_ret_sf)
     %t9 = COPY %v1
     %gp = COPY killed %s0
     JumpLinkReg16 killed %v1, csr_mips16rethelper, implicit-def %ra, implicit killed %t9, implicit %v0, implicit killed %gp, implicit-def %sp
     %s0, %ra, %s2 = RestoreX16 32, implicit-def %sp, implicit %sp
     RetRA16 implicit %v0
 ...

test/CodeGen/Mips/stchar.ll

 ; RUN: llc  -march=mipsel -mattr=mips16 -relocation-model=pic -O3 < %s | FileCheck %s -check-prefix=16_h
 ; RUN: llc  -march=mipsel -mattr=mips16 -relocation-model=pic -O3 < %s | FileCheck %s -check-prefix=16_b
 
 @.str = private unnamed_addr constant [9 x i8] c"%hd %c \0A\00", align 1
 @sp = common global i16* null, align 4
 @cp = common global i8* null, align 4
 
-define void @p1(i16 signext %s, i8 signext %c) nounwind {
-entry:
-  %conv = sext i16 %s to i32
-  %conv1 = sext i8 %c to i32
-  %call = tail call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([9 x i8], [9 x i8]* @.str, i32 0, i32 0), i32 %conv, i32 %conv1) nounwind
-  ret void
-}
-
 declare i32 @printf(i8* nocapture, ...) nounwind
 
-define void @p2() nounwind {
-entry:
-  %0 = load i16*, i16** @sp, align 4
-  %1 = load i16, i16* %0, align 2
-  %2 = load i8*, i8** @cp, align 4
-  %3 = load i8, i8* %2, align 1
-  %conv.i = sext i16 %1 to i32
-  %conv1.i = sext i8 %3 to i32
-  %call.i = tail call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([9 x i8], [9 x i8]* @.str, i32 0, i32 0), i32 %conv.i, i32 %conv1.i) nounwind
-  %4 = load i16*, i16** @sp, align 4
-  store i16 32, i16* %4, align 2
-  %5 = load i8*, i8** @cp, align 4
-  store i8 97, i8* %5, align 1
-  ret void
-}
-
 define void @test() nounwind {
 entry:
   %s = alloca i16, align 4
   %c = alloca i8, align 4
   store i16 16, i16* %s, align 4
   store i8 99, i8* %c, align 4
   store i16* %s, i16** @sp, align 4
   store i8* %c, i8** @cp, align 4

 ; 16_b-LABEL: test:
 ; 16_h-LABEL: test:
 ; 16_b: sb  ${{[0-9]+}}, [[offset1:[0-9]+]](${{[0-9]+}})
 ; 16_b: lb      ${{[0-9]+}}, [[offset1]](${{[0-9]+}})
 ; 16_h: sh  ${{[0-9]+}}, [[offset2:[0-9]+]](${{[0-9]+}})
 ; 16_h: lh      ${{[0-9]+}}, [[offset2]](${{[0-9]+}})
 }
 
-define i32 @main() nounwind {
-entry:
-  %s.i = alloca i16, align 4
-  %c.i = alloca i8, align 4
-  %0 = bitcast i16* %s.i to i8*
-  call void @llvm.lifetime.start(i64 -1, i8* %0) nounwind
-  call void @llvm.lifetime.start(i64 -1, i8* %c.i) nounwind
-  store i16 16, i16* %s.i, align 4
-  store i8 99, i8* %c.i, align 4
-  store i16* %s.i, i16** @sp, align 4
-  store i8* %c.i, i8** @cp, align 4
-  %call.i.i.i = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([9 x i8], [9 x i8]* @.str, i32 0, i32 0), i32 16, i32 99) nounwind
-  %1 = load i16*, i16** @sp, align 4
-  store i16 32, i16* %1, align 2
-  %2 = load i8*, i8** @cp, align 4
-  store i8 97, i8* %2, align 1
-  %3 = load i16, i16* %s.i, align 4
-  %4 = load i8, i8* %c.i, align 4
-  %conv.i.i = sext i16 %3 to i32
-  %conv1.i.i = sext i8 %4 to i32
-  %call.i.i = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([9 x i8], [9 x i8]* @.str, i32 0, i32 0), i32 %conv.i.i, i32 %conv1.i.i) nounwind
-  call void @llvm.lifetime.end(i64 -1, i8* %0) nounwind
-  call void @llvm.lifetime.end(i64 -1, i8* %c.i) nounwind
-  ret i32 0
-}
-
 declare void @llvm.lifetime.start(i64, i8* nocapture) nounwind
 
 declare void @llvm.lifetime.end(i64, i8* nocapture) nounwind
 

test/CodeGen/Mips/stldst.ll

entry:
   %sub5 = add nsw i32 %6, -10
   %7 = load i32, i32* @rrrr, align 4
   %add6 = add nsw i32 %7, 6
 
   %call = tail call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([32 x i8], [32 x i8]* @.str, i32 0, i32 0), i32 %sub5, i32 %add6, i32 %0, i32 %1, i32 %2, i32 %3, i32 %4, i32 %5, i32 %6, i32 %7) nounwind
   %call7 = tail call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([32 x i8], [32 x i8]* @.str, i32 0, i32 0), i32 %0, i32 %1, i32 %add, i32 %add1, i32 %sub, i32 %add2, i32 %add3, i32 %sub4, i32 %sub5, i32 %add6) nounwind
   ret i32 0
 }
-; 16: sw  ${{[0-9]+}}, {{[0-9]+}} ( $sp );         # 4-byte Folded Spill
-; 16: lw  ${{[0-9]+}}, {{[0-9]+}} ( $sp );         # 4-byte Folded Reload
-; 16: sw  ${{[0-9]+}}, {{[0-9]+}} ( $sp );         # 4-byte Folded Spill
-; 16: lw  ${{[0-9]+}}, {{[0-9]+}} ( $sp );         # 4-byte Folded Reload
+; 16: sw  ${{[0-9]+}}, {{[0-9]+}}($sp)         # 4-byte Folded Spill
+; 16: lw  ${{[0-9]+}}, {{[0-9]+}}($sp)         # 4-byte Folded Reload
+; 16: sw  ${{[0-9]+}}, {{[0-9]+}}($sp)         # 4-byte Folded Spill
+; 16: lw  ${{[0-9]+}}, {{[0-9]+}}($sp)         # 4-byte Folded Reload
 
 declare i32 @printf(i8* nocapture, ...) nounwind

test/CodeGen/Mips/tailcall.ll

-; RUN: llc -march=mipsel -relocation-model=pic -enable-mips-tail-calls < %s | \
-; RUN:     FileCheck %s -check-prefix=PIC32
-; RUN: llc -march=mipsel -relocation-model=static \
-; RUN:     -enable-mips-tail-calls < %s | FileCheck %s -check-prefix=STATIC32
+; RUN: llc -march=mipsel -relocation-model=pic -enable-mips-tail-calls \
+; RUN:     -verify-machineinstrs < %s | FileCheck %s -check-prefix=PIC32
+; RUN: llc -march=mipsel -relocation-model=static -enable-mips-tail-calls \
+; RUN:     -verify-machineinstrs < %s | FileCheck %s -check-prefix=STATIC32
 ; RUN: llc -march=mips64el -mcpu=mips64r2 -enable-mips-tail-calls \
-; RUN:     < %s | FileCheck %s -check-prefix=N64
+; RUN:     -verify-machineinstrs < %s | FileCheck %s -check-prefix=N64
 ; RUN: llc -march=mipsel -mattr=mips16 -relocation-model=pic \
-; RUN:     -enable-mips-tail-calls < %s | FileCheck %s -check-prefix=PIC16
+; RUN:     -enable-mips-tail-calls -verify-machineinstrs < %s | \
+; RUN:     FileCheck %s -check-prefix=PIC16
 
 @g0 = common global i32 0, align 4
 @g1 = common global i32 0, align 4
 @g2 = common global i32 0, align 4
 @g3 = common global i32 0, align 4
 @g4 = common global i32 0, align 4
 @g5 = common global i32 0, align 4
 @g6 = common global i32 0, align 4