[RISCV] Add 16 bit GPR sub-register for Zhinx.

llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp

@@ -480,7 +480,13 @@ struct RISCVOperand final : public MCParsedAsmOperand {
            RISCVMCRegisterClasses[RISCV::GPRRegClassID].contains(Reg.RegNum);
   }
 
+  bool isGPRF16() const {
+    return Kind == KindTy::Register &&
+           RISCVMCRegisterClasses[RISCV::GPRF16RegClassID].contains(Reg.RegNum);
+  }
+
   bool isGPRAsFPR() const { return isGPR() && Reg.IsGPRAsFPR; }
+  bool isGPRAsFPR16() const { return isGPRF16() && Reg.IsGPRAsFPR; }
   bool isGPRPairAsFPR() const { return isGPRPair() && Reg.IsGPRAsFPR; }
 
   bool isGPRPair() const {
@@ -1342,6 +1348,10 @@ unsigned RISCVAsmParser::validateTargetOperandClass(MCParsedAsmOperand &AsmOp,
     Op.Reg.RegNum = convertFPR64ToFPR16(Reg);
     return Match_Success;
   }
+  if (Kind == MCK_GPRAsFPR16 && Op.isGPRAsFPR()) {
+    Op.Reg.RegNum = Reg - RISCV::X0 + RISCV::X0_H;
+    return Match_Success;
+  }
 
   // There are some GPRF64AsFPR instructions that have no RV32 equivalent. We
   // reject them at parsing thinking we should match as GPRPairAsFPR for RV32.

llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp

@@ -81,6 +81,19 @@ static DecodeStatus DecodeGPRRegisterClass(MCInst &Inst, uint32_t RegNo,
   return MCDisassembler::Success;
 }
 
+static DecodeStatus DecodeGPRF16RegisterClass(MCInst &Inst, uint32_t RegNo,
+                                              uint64_t Address,
+                                              const MCDisassembler *Decoder) {
+  bool IsRVE = Decoder->getSubtargetInfo().hasFeature(RISCV::FeatureStdExtE);
+
+  if (RegNo >= 32 || (IsRVE && RegNo >= 16))
+    return MCDisassembler::Fail;
+
+  MCRegister Reg = RISCV::X0_H + RegNo;
+  Inst.addOperand(MCOperand::createReg(Reg));
+  return MCDisassembler::Success;
+}
+
 static DecodeStatus DecodeGPRX1X5RegisterClass(MCInst &Inst, uint32_t RegNo,
                                                uint64_t Address,
                                                const MCDisassembler *Decoder) {

llvm/lib/Target/RISCV/RISCVCallingConv.cpp

@@ -139,6 +139,23 @@ ArrayRef<MCPhysReg> RISCV::getArgGPRs(const RISCVABI::ABI ABI) {
   return ArrayRef(ArgIGPRs);
 }
 
+static ArrayRef<MCPhysReg> getArgGPR16s(const RISCVABI::ABI ABI) {
+  // The GPRs used for passing arguments in the ILP32* and LP64* ABIs, except
+  // the ILP32E ABI.
+  static const MCPhysReg ArgIGPRs[] = {RISCV::X10_H, RISCV::X11_H, RISCV::X12_H,
+                                       RISCV::X13_H, RISCV::X14_H, RISCV::X15_H,
+                                       RISCV::X16_H, RISCV::X17_H};
+  // The GPRs used for passing arguments in the ILP32E/ILP64E ABI.
+  static const MCPhysReg ArgEGPRs[] = {RISCV::X10_H, RISCV::X11_H,
+                                       RISCV::X12_H, RISCV::X13_H,
+                                       RISCV::X14_H, RISCV::X15_H};
+
+  if (ABI == RISCVABI::ABI_ILP32E || ABI == RISCVABI::ABI_LP64E)
+    return ArrayRef(ArgEGPRs);
+
+  return ArrayRef(ArgIGPRs);
+}
+
 static ArrayRef<MCPhysReg> getFastCCArgGPRs(const RISCVABI::ABI ABI) {
   // The GPRs used for passing arguments in the FastCC, X5 and X6 might be used
   // for save-restore libcall, so we don't use them.
@@ -157,6 +174,26 @@ static ArrayRef<MCPhysReg> getFastCCArgGPRs(const RISCVABI::ABI ABI) {
   return ArrayRef(FastCCIGPRs);
 }
 
+static ArrayRef<MCPhysReg> getFastCCArgGPRF16s(const RISCVABI::ABI ABI) {
+  // The GPRs used for passing arguments in the FastCC, X5 and X6 might be used
+  // for save-restore libcall, so we don't use them.
+  // Don't use X7 for fastcc, since Zicfilp uses X7 as the label register.
+  static const MCPhysReg FastCCIGPRs[] = {
+      RISCV::X10_H, RISCV::X11_H, RISCV::X12_H, RISCV::X13_H,
+      RISCV::X14_H, RISCV::X15_H, RISCV::X16_H, RISCV::X17_H,
+      RISCV::X28_H, RISCV::X29_H, RISCV::X30_H, RISCV::X31_H};
+
+  // The GPRs used for passing arguments in the FastCC when using ILP32E/ILP64E.
+  static const MCPhysReg FastCCEGPRs[] = {RISCV::X10_H, RISCV::X11_H,
+                                          RISCV::X12_H, RISCV::X13_H,
+                                          RISCV::X14_H, RISCV::X15_H};
+
+  if (ABI == RISCVABI::ABI_ILP32E || ABI == RISCVABI::ABI_LP64E)
+    return ArrayRef(FastCCEGPRs);
+
+  return ArrayRef(FastCCIGPRs);
+}
+
 // Pass a 2*XLEN argument that has been split into two XLEN values through
 // registers or the stack as necessary.
 static bool CC_RISCVAssign2XLen(unsigned XLen, CCState &State, CCValAssign VA1,
@@ -320,6 +357,13 @@ bool llvm::CC_RISCV(unsigned ValNo, MVT ValVT, MVT LocVT,
     }
   }
 
+  if ((ValVT == MVT::f16 && Subtarget.hasStdExtZhinxmin())) {
+    if (MCRegister Reg = State.AllocateReg(getArgGPR16s(ABI))) {
+      State.addLoc(CCValAssign::getReg(ValNo, ValVT, Reg, LocVT, LocInfo));
+      return false;
+    }
+  }
+
   ArrayRef<MCPhysReg> ArgGPRs = RISCV::getArgGPRs(ABI);
 
   // Zfinx/Zdinx use GPR without a bitcast when possible.
@@ -566,8 +610,7 @@ bool llvm::CC_RISCV_FastCC(unsigned ValNo, MVT ValVT, MVT LocVT,
   }
 
   // Check if there is an available GPR before hitting the stack.
-  if ((LocVT == MVT::f16 && Subtarget.hasStdExtZhinxmin()) ||
-      (LocVT == MVT::f32 && Subtarget.hasStdExtZfinx()) ||
+  if ((LocVT == MVT::f32 && Subtarget.hasStdExtZfinx()) ||
       (LocVT == MVT::f64 && Subtarget.is64Bit() &&
        Subtarget.hasStdExtZdinx())) {
     if (MCRegister Reg = State.AllocateReg(getFastCCArgGPRs(ABI))) {
@@ -582,6 +625,14 @@ bool llvm::CC_RISCV_FastCC(unsigned ValNo, MVT ValVT, MVT LocVT,
     }
   }
 
+  // Check if there is an available GPRF16 before hitting the stack.
+  if ((LocVT == MVT::f16 && Subtarget.hasStdExtZhinxmin())) {
+    if (MCRegister Reg = State.AllocateReg(getFastCCArgGPRF16s(ABI))) {
+      State.addLoc(CCValAssign::getReg(ValNo, ValVT, Reg, LocVT, LocInfo));
+      return false;
+    }
+  }
+
   if (LocVT == MVT::f16 || LocVT == MVT::bf16) {
     int64_t Offset2 = State.AllocateStack(2, Align(2));
     State.addLoc(CCValAssign::getMem(ValNo, ValVT, Offset2, LocVT, LocInfo));

llvm/lib/Target/RISCV/RISCVDeadRegisterDefinitions.cpp

@@ -93,14 +93,19 @@ bool RISCVDeadRegisterDefinitions::runOnMachineFunction(MachineFunction &MF) {
           continue;
         LLVM_DEBUG(dbgs() << "    Dead def operand #" << I << " in:\n      ";
                    MI.print(dbgs()));
+        Register X0Reg;
         const TargetRegisterClass *RC = TII->getRegClass(Desc, I, TRI, MF);
-        if (!(RC && RC->contains(RISCV::X0))) {
+        if (RC && RC->contains(RISCV::X0)) {
+          X0Reg = RISCV::X0;
+        } else if (RC && RC->contains(RISCV::X0_H)) {
+          X0Reg = RISCV::X0_H;
+        } else {
           LLVM_DEBUG(dbgs() << "    Ignoring, register is not a GPR.\n");
           continue;
         }
         assert(LIS.hasInterval(Reg));
         LIS.removeInterval(Reg);
-        MO.setReg(RISCV::X0);
+        MO.setReg(X0Reg);
         LLVM_DEBUG(dbgs() << "    Replacing with zero register. New:\n      ";
                    MI.print(dbgs()));
         ++NumDeadDefsReplaced;

llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp

@@ -959,7 +959,10 @@ void RISCVDAGToDAGISel::Select(SDNode *Node) {
     }
 
     SDNode *Res;
-    if (Opc == RISCV::FCVT_D_W_IN32X || Opc == RISCV::FCVT_D_W)
+    if (VT.SimpleTy == MVT::f16 && Opc == RISCV::COPY) {
+      Res =
+          CurDAG->getTargetExtractSubreg(RISCV::sub_16, DL, VT, Imm).getNode();
+    } else if (Opc == RISCV::FCVT_D_W_IN32X || Opc == RISCV::FCVT_D_W)
       Res = CurDAG->getMachineNode(
           Opc, DL, VT, Imm,
           CurDAG->getTargetConstant(RISCVFPRndMode::RNE, DL, XLenVT));

llvm/lib/Target/RISCV/RISCVInstrInfo.cpp

@@ -458,6 +458,23 @@ void RISCVInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
     return;
   }
 
+  if (RISCV::GPRF16RegClass.contains(DstReg, SrcReg)) {
+    if (STI.hasStdExtZhinx()) {
+      BuildMI(MBB, MBBI, DL, get(RISCV::FSGNJ_H_INX), DstReg)
+          .addReg(SrcReg, getKillRegState(KillSrc))
+          .addReg(SrcReg, getKillRegState(KillSrc));
+      return;
+    }
+    DstReg =
+        TRI->getMatchingSuperReg(DstReg, RISCV::sub_16, &RISCV::GPRRegClass);
+    SrcReg =
+        TRI->getMatchingSuperReg(SrcReg, RISCV::sub_16, &RISCV::GPRRegClass);
+    BuildMI(MBB, MBBI, DL, get(RISCV::ADDI), DstReg)
+        .addReg(SrcReg, getKillRegState(KillSrc))
+        .addImm(0);
+    return;
+  }
+
   if (RISCV::GPRPairRegClass.contains(DstReg, SrcReg)) {
     // Emit an ADDI for both parts of GPRPair.
     BuildMI(MBB, MBBI, DL, get(RISCV::ADDI),
@@ -579,6 +596,9 @@ void RISCVInstrInfo::storeRegToStackSlot(MachineBasicBlock &MBB,
     Opcode = TRI->getRegSizeInBits(RISCV::GPRRegClass) == 32 ?
              RISCV::SW : RISCV::SD;
     IsScalableVector = false;
+  } else if (RISCV::GPRF16RegClass.hasSubClassEq(RC)) {
+    Opcode = RISCV::SH_INX;
+    IsScalableVector = false;
   } else if (RISCV::GPRPairRegClass.hasSubClassEq(RC)) {
     Opcode = RISCV::PseudoRV32ZdinxSD;
     IsScalableVector = false;
@@ -662,6 +682,9 @@ void RISCVInstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
     Opcode = TRI->getRegSizeInBits(RISCV::GPRRegClass) == 32 ?
              RISCV::LW : RISCV::LD;
     IsScalableVector = false;
+  } else if (RISCV::GPRF16RegClass.hasSubClassEq(RC)) {
+    Opcode = RISCV::LH_INX;
+    IsScalableVector = false;
   } else if (RISCV::GPRPairRegClass.hasSubClassEq(RC)) {
     Opcode = RISCV::PseudoRV32ZdinxLD;
     IsScalableVector = false;

llvm/lib/Target/RISCV/RISCVInstrInfo.td

@@ -514,8 +514,8 @@ class BranchCC_rri<bits<3> funct3, string opcodestr>
 }
 
 let hasSideEffects = 0, mayLoad = 1, mayStore = 0 in {
-class Load_ri<bits<3> funct3, string opcodestr>
-    : RVInstI<funct3, OPC_LOAD, (outs GPR:$rd), (ins GPRMem:$rs1, simm12:$imm12),
+class Load_ri<bits<3> funct3, string opcodestr, DAGOperand rty = GPR>
+    : RVInstI<funct3, OPC_LOAD, (outs rty:$rd), (ins GPRMem:$rs1, simm12:$imm12),
               opcodestr, "$rd, ${imm12}(${rs1})">;
 
 class HLoad_r<bits<7> funct7, bits<5> funct5, string opcodestr>
@@ -529,9 +529,9 @@ class HLoad_r<bits<7> funct7, bits<5> funct5, string opcodestr>
 // reflecting the order these fields are specified in the instruction
 // encoding.
 let hasSideEffects = 0, mayLoad = 0, mayStore = 1 in {
-class Store_rri<bits<3> funct3, string opcodestr>
+class Store_rri<bits<3> funct3, string opcodestr, DAGOperand rty = GPR>
     : RVInstS<funct3, OPC_STORE, (outs),
-              (ins GPR:$rs2, GPRMem:$rs1, simm12:$imm12),
+              (ins rty:$rs2, GPRMem:$rs1, simm12:$imm12),
               opcodestr, "$rs2, ${imm12}(${rs1})">;
 
 class HStore_rr<bits<7> funct7, string opcodestr>

llvm/lib/Target/RISCV/RISCVInstrInfoZfh.td

@@ -33,9 +33,14 @@ def riscv_fmv_x_signexth
 
 // Zhinxmin and Zhinx
 
+def GPRAsFPR16 : AsmOperandClass {
+  let Name = "GPRAsFPR16";
+  let ParserMethod = "parseGPRAsFPR";
+  let RenderMethod = "addRegOperands";
+}
+
 def FPR16INX : RegisterOperand<GPRF16> {
-  let ParserMatchClass = GPRAsFPR;
-  let DecoderMethod = "DecodeGPRRegisterClass";
+  let ParserMatchClass = GPRAsFPR16;
 }
 
 def ZfhExt     : ExtInfo<"", "", [HasStdExtZfh],
@@ -84,6 +89,12 @@ def FLH : FPLoad_r<0b001, "flh", FPR16, WriteFLD16>;
 def FSH : FPStore_r<0b001, "fsh", FPR16, WriteFST16>;
 } // Predicates = [HasHalfFPLoadStoreMove]
 
+let Predicates = [HasStdExtZhinxmin], isCodeGenOnly = 1 in {
+def LH_INX : Load_ri<0b001, "lh", GPRF16>, Sched<[WriteLDH, ReadMemBase]>;
+def SH_INX : Store_rri<0b001, "sh", GPRF16>,
+             Sched<[WriteSTH, ReadStoreData, ReadMemBase]>;
+}
+
 foreach Ext = ZfhExts in {
   let SchedRW = [WriteFMA16, ReadFMA16, ReadFMA16, ReadFMA16Addend] in {
     defm FMADD_H  : FPFMA_rrr_frm_m<OPC_MADD,  0b10, "fmadd.h",  Ext>;
@@ -426,13 +437,10 @@ let Predicates = [HasStdExtZhinxmin] in {
 defm Select_FPR16INX : SelectCC_GPR_rrirr<FPR16INX, f16>;
 
 /// Loads
-def : Pat<(f16 (load (AddrRegImm (XLenVT GPR:$rs1), simm12:$imm12))),
-          (COPY_TO_REGCLASS (LH GPR:$rs1, simm12:$imm12), GPRF16)>;
+def : LdPat<load, LH_INX, f16>;
 
 /// Stores
-def : Pat<(store (f16 FPR16INX:$rs2),
-                 (AddrRegImm (XLenVT GPR:$rs1), simm12:$imm12)),
-          (SH (COPY_TO_REGCLASS FPR16INX:$rs2, GPR), GPR:$rs1, simm12:$imm12)>;
+def : StPat<store, SH_INX, GPRF16, f16>;
 } // Predicates = [HasStdExtZhinxmin]
 
 let Predicates = [HasStdExtZfhmin] in {
@@ -458,8 +466,8 @@ def : Pat<(any_fpround FPR32INX:$rs1), (FCVT_H_S_INX FPR32INX:$rs1, FRM_DYN)>;
 def : Pat<(any_fpextend FPR16INX:$rs1), (FCVT_S_H_INX FPR16INX:$rs1, FRM_RNE)>;
 
 // Moves (no conversion)
-def : Pat<(f16 (riscv_fmv_h_x GPR:$src)), (COPY_TO_REGCLASS GPR:$src, GPR)>;
-def : Pat<(riscv_fmv_x_anyexth FPR16INX:$src), (COPY_TO_REGCLASS FPR16INX:$src, GPR)>;
+def : Pat<(f16 (riscv_fmv_h_x GPR:$src)), (EXTRACT_SUBREG GPR:$src, sub_16)>;
+def : Pat<(riscv_fmv_x_anyexth FPR16INX:$src), (INSERT_SUBREG (XLenVT (IMPLICIT_DEF)), FPR16INX:$src, sub_16)>;
 
 def : Pat<(fcopysign FPR32INX:$rs1, FPR16INX:$rs2), (FSGNJ_S_INX $rs1, (FCVT_S_H_INX $rs2, FRM_RNE))>;
 } // Predicates = [HasStdExtZhinxmin]

llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp

@@ -115,11 +115,11 @@ BitVector RISCVRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
   }
 
   // Use markSuperRegs to ensure any register aliases are also reserved
-  markSuperRegs(Reserved, RISCV::X2); // sp
-  markSuperRegs(Reserved, RISCV::X3); // gp
-  markSuperRegs(Reserved, RISCV::X4); // tp
+  markSuperRegs(Reserved, RISCV::X2_H); // sp
+  markSuperRegs(Reserved, RISCV::X3_H); // gp
+  markSuperRegs(Reserved, RISCV::X4_H); // tp
   if (TFI->hasFP(MF))
-    markSuperRegs(Reserved, RISCV::X8); // fp
+    markSuperRegs(Reserved, RISCV::X8_H); // fp
   // Reserve the base register if we need to realign the stack and allocate
   // variable-sized objects at runtime.
   if (TFI->hasBP(MF))
@@ -131,7 +131,7 @@ BitVector RISCVRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
 
   // There are only 16 GPRs for RVE.
   if (Subtarget.hasStdExtE())
-    for (MCPhysReg Reg = RISCV::X16; Reg <= RISCV::X31; Reg++)
+    for (MCPhysReg Reg = RISCV::X16_H; Reg <= RISCV::X31_H; Reg++)
       markSuperRegs(Reserved, Reg);
 
   // V registers for code generation. We handle them manually.
@@ -150,8 +150,8 @@ BitVector RISCVRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
   if (MF.getFunction().getCallingConv() == CallingConv::GRAAL) {
     if (Subtarget.hasStdExtE())
       report_fatal_error("Graal reserved registers do not exist in RVE");
-    markSuperRegs(Reserved, RISCV::X23);
-    markSuperRegs(Reserved, RISCV::X27);
+    markSuperRegs(Reserved, RISCV::X23_H);
+    markSuperRegs(Reserved, RISCV::X27_H);
   }
 
   // Shadow stack pointer.