[RISCV] Add MIPS extensions

llvm/docs/RISCVUsage.rst

@@ -456,6 +456,12 @@ The current vendor extensions supported are:
 ``experimental-Xqcisls``
   LLVM implements `version 0.2 of the Qualcomm uC Scaled Load Store extension specification <https://github.com/quic/riscv-unified-db/releases/latest>`__ by Qualcomm.  All instructions are prefixed with `qc.` as described in the specification. These instructions are only available for riscv32.
 
+``Xmipscmove``
+  LLVM implements conditional move for the `p8700 processor <https://mips.com/products/hardware/p8700/>` by MIPS.
+
+``Xmipslsp``
+  LLVM implements load/store pair instructions for the `p8700 processor <https://mips.com/products/hardware/p8700/>` by MIPS.
+
 Experimental C Intrinsics
 =========================
 

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

@@ -877,6 +877,16 @@ struct RISCVOperand final : public MCParsedAsmOperand {
            VK == RISCVMCExpr::VK_RISCV_None;
   }
 
+  bool isUImm7Lsb000() const {
+    if (!isImm())
+      return false;
+    int64_t Imm;
+    RISCVMCExpr::VariantKind VK = RISCVMCExpr::VK_RISCV_None;
+    bool IsConstantImm = evaluateConstantImm(getImm(), Imm, VK);
+    return IsConstantImm && isShiftedUInt<4, 3>(Imm) &&
+           VK == RISCVMCExpr::VK_RISCV_None;
+  }
+
   bool isUImm8Lsb00() const {
     if (!isImm())
       return false;

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

@@ -667,6 +667,11 @@ DecodeStatus RISCVDisassembler::getInstruction32(MCInst &MI, uint64_t &Size,
                         "SiFive sf.cflush.d.l1 custom opcode table");
   TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXSfcease, DecoderTableXSfcease32,
                         "SiFive sf.cease custom opcode table");
+  TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorMIPSLoadStorePairs,
+                        DecoderTableXmipslsp32,
+                        "MIPS mips.lsp custom opcode table");
+  TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorMIPSCMove, DecoderTableXmipscomve32,
+                        "MIPS mips.ccmov custom opcode table");
   TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXCVbitmanip,
                         DecoderTableXCVbitmanip32,
                         "CORE-V Bit Manipulation custom opcode table");

llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.h

@@ -308,6 +308,7 @@ enum OperandType : unsigned {
   OPERAND_UIMM6_LSB0,
   OPERAND_UIMM7,
   OPERAND_UIMM7_LSB00,
+  OPERAND_UIMM7_LSB000,
   OPERAND_UIMM8_LSB00,
   OPERAND_UIMM8,
   OPERAND_UIMM8_LSB000,

llvm/lib/Target/RISCV/RISCV.h

@@ -84,6 +84,8 @@ void initializeRISCVMoveMergePass(PassRegistry &);
 
 FunctionPass *createRISCVPushPopOptimizationPass();
 void initializeRISCVPushPopOptPass(PassRegistry &);
+FunctionPass *createRISCVLoadStoreOptPass();
+void initializeRISCVLoadStoreOptPass(PassRegistry &);
 
 FunctionPass *createRISCVZacasABIFixPass();
 void initializeRISCVZacasABIFixPass(PassRegistry &);

llvm/lib/Target/RISCV/RISCVFeatures.td

@@ -1448,3 +1448,18 @@ def FeatureTaggedGlobals : SubtargetFeature<"tagged-globals",
     "AllowTaggedGlobals",
     "true", "Use an instruction sequence for taking the address of a global "
     "that allows a memory tag in the upper address bits">;
+
+def FeatureVendorMIPSCMove : SubtargetFeature<"xmipscmove", "HasVendorMIPSCMove",
+                                       "true", "Using CCMov",
+                                       [Feature64Bit]>;
+def HasVendorMIPSCMove
+    : Predicate<"Subtarget->useCCMovInsn()">,
+      AssemblerPredicate<(all_of FeatureVendorMIPSCMove),
+                         "'Xmipscmove' ('mips.ccmov' instruction)">;
+def FeatureVendorMIPSLoadStorePairs
+    : SubtargetFeature<"xmipslsp", "HasMIPSLSP", "true",
+                       "Optimize for hardware load-store bonding">;
+def HasVendorMIPSLoadStorePairs
+    : Predicate<"Subtarget->useLoadStorePairs()">,
+      AssemblerPredicate<(all_of FeatureVendorMIPSLoadStorePairs),
+                         "'Xmipslsp' (load and store pair instructions)">;

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

@@ -409,7 +409,9 @@ RISCVTargetLowering::RISCVTargetLowering(const TargetMachine &TM,
     setOperationAction(ISD::ABS, MVT::i32, Custom);
   }
 
-  if (!Subtarget.hasVendorXTHeadCondMov())
+  if (Subtarget.hasVendorMIPSCMove())
+    setOperationAction(ISD::SELECT, XLenVT, Legal);
+  else if (!Subtarget.hasVendorXTHeadCondMov())
     setOperationAction(ISD::SELECT, XLenVT, Custom);
 
   static const unsigned FPLegalNodeTypes[] = {

llvm/lib/Target/RISCV/RISCVInstrFormats.td

@@ -514,6 +514,78 @@ class RVInstJ<RISCVOpcode opcode, dag outs, dag ins, string opcodestr,
   let Inst{6-0} = opcode.Value;
 }
 
+//===----------------------------------------------------------------------===//
+// MIPS custom instruction formats
+//===----------------------------------------------------------------------===//
+
+// Load double pair format.
+class LDPFormat<dag outs, dag ins, string opcodestr, string argstr>
+    : RVInst<outs, ins, opcodestr, argstr, [], InstFormatI> {
+  bits<7> imm7;
+  bits<5> rs1;
+  bits<5> rd1;
+  bits<5> rd2;
+
+  let Inst{31-27} = rd2;
+  let Inst{26-23} = imm7{6-3};
+  let Inst{22-20} = 0b000;
+  let Inst{19-15} = rs1;
+  let Inst{14-12} = 0b100;
+  let Inst{11-7} = rd1;
+  let Inst{6-0} = OPC_CUSTOM_0.Value;
+}
+
+// Load word pair format.
+class LWPFormat<dag outs, dag ins, string opcodestr, string argstr>
+    : RVInst<outs, ins, opcodestr, argstr, [], InstFormatI> {
+  bits<7> imm7;
+  bits<5> rs1;
+  bits<5> rd1;
+  bits<5> rd2;
+
+  let Inst{31-27} = rd2;
+  let Inst{26-22} = imm7{6-2};
+  let Inst{21-20} = 0b01;
+  let Inst{19-15} = rs1;
+  let Inst{14-12} = 0b100;
+  let Inst{11-7} = rd1;
+  let Inst{6-0} = OPC_CUSTOM_0.Value;
+}
+
+// Store double pair format.
+class SDPFormat<dag outs, dag ins, string opcodestr, string argstr>
+    : RVInst<outs, ins, opcodestr, argstr, [], InstFormatI> {
+  bits<7> imm7;
+  bits<5> rs3;
+  bits<5> rs2;
+  bits<5> rs1;
+
+  let Inst{31-27} = rs3;
+  let Inst{26-25} = imm7{6-5};
+  let Inst{24-20} = rs2;
+  let Inst{19-15} = rs1;
+  let Inst{14-12} = 0b101;
+  let Inst{11-10} = imm7{4-3};
+  let Inst{9-0} = 0b0000001011;
+}
+
+// Store word pair format.
+class SWPFormat<dag outs, dag ins, string opcodestr, string argstr>
+    : RVInst<outs, ins, opcodestr, argstr, [], InstFormatI> {
+  bits<7> imm7;
+  bits<5> rs3;
+  bits<5> rs2;
+  bits<5> rs1;
+
+  let Inst{31-27} = rs3;
+  let Inst{26-25} = imm7{6-5};
+  let Inst{24-20} = rs2;
+  let Inst{19-15} = rs1;
+  let Inst{14-12} = 0b101;
+  let Inst{11-9} = imm7{4-2};
+  let Inst{8-0} = 0b010001011;
+}
+
 //===----------------------------------------------------------------------===//
 // Instruction classes for .insn directives
 //===----------------------------------------------------------------------===//

llvm/lib/Target/RISCV/RISCVInstrInfo.cpp

@@ -2489,6 +2489,9 @@ bool RISCVInstrInfo::verifyInstruction(const MachineInstr &MI,
         case RISCVOp::OPERAND_UIMM7_LSB00:
           Ok = isShiftedUInt<5, 2>(Imm);
           break;
+        case RISCVOp::OPERAND_UIMM7_LSB000:
+          Ok = isShiftedUInt<4, 3>(Imm);
+          break;
         case RISCVOp::OPERAND_UIMM8_LSB00:
           Ok = isShiftedUInt<6, 2>(Imm);
           break;

llvm/lib/Target/RISCV/RISCVInstrInfo.td

@@ -394,6 +394,10 @@ def ixlenimm_li_restricted : Operand<XLenVT> {
 
 // Standalone (codegen-only) immleaf patterns.
 
+// A 12-bit signed immediate plus one where the imm range will be -2047~2048.
+def simm12_plus1 : ImmLeaf<XLenVT,
+  [{return (isInt<12>(Imm) && Imm != -2048) || Imm == 2048;}]>;
+
 // A 6-bit constant greater than 32.
 def uimm6gt32 : ImmLeaf<XLenVT, [{
   return isUInt<6>(Imm) && Imm > 32;
@@ -2123,6 +2127,7 @@ include "RISCVInstrInfoSFB.td"
 include "RISCVInstrInfoXCV.td"
 include "RISCVInstrInfoXwch.td"
 include "RISCVInstrInfoXqci.td"
+include "RISCVInstrInfoXMips.td"
 
 //===----------------------------------------------------------------------===//
 // Global ISel

llvm/lib/Target/RISCV/RISCVInstrInfoC.td

@@ -109,6 +109,21 @@ def uimm7_lsb00 : RISCVOp,
   }];
 }
 
+// A 7-bit unsigned immediate where the least significant three bits are zero.
+def uimm7_lsb000 : RISCVOp,
+                   ImmLeaf<XLenVT, [{return isShiftedUInt<4, 3>(Imm);}]> {
+  let ParserMatchClass = UImmAsmOperand<7, "Lsb000">;
+  let EncoderMethod = "getImmOpValue";
+  let DecoderMethod = "decodeUImmOperand<7>";
+  let OperandType = "OPERAND_UIMM7_LSB000";
+  let MCOperandPredicate = [{
+    int64_t Imm;
+    if (!MCOp.evaluateAsConstantImm(Imm))
+      return false;
+    return isShiftedUInt<4, 3>(Imm);
+  }];
+}
+
 // A 8-bit unsigned immediate where the least significant two bits are zero.
 def uimm8_lsb00 : RISCVOp,
                   ImmLeaf<XLenVT, [{return isShiftedUInt<6, 2>(Imm);}]> {

llvm/lib/Target/RISCV/RISCVInstrInfoXMips.td

@@ -0,0 +1,82 @@
+//===-- RISCVInstrInfoXMips.td -----------------------------*- tablegen -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file describes the vendor extensions defined by MIPS.
+//
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+
+// MIPS extensions
+//===----------------------------------------------------------------------===//
+
+let Predicates = [HasVendorMIPSCMove], hasSideEffects = 0, mayLoad = 0, mayStore = 0, DecoderNamespace = "Xmipscomve" in {
+def CCMOV : RVInstR4<0b11, 0b011, OPC_CUSTOM_0, (outs GPR:$rd),
+                    (ins GPR:$rs1, GPR:$rs2, GPR:$rs3),
+                    "mips.ccmov", "$rd, $rs2, $rs1, $rs3">,
+           Sched<[]>;
+}
+
+let Predicates = [HasVendorMIPSCMove] in {
+def : Pat<(select (XLenVT (setne (XLenVT GPR:$rs2), (XLenVT 0))),
+                  (XLenVT GPR:$rs1), (XLenVT GPR:$rs3)),
+          (CCMOV GPR:$rs1, GPR:$rs2, GPR:$rs3)>;
+def : Pat<(select (XLenVT (setne (XLenVT GPR:$x), (XLenVT simm12_plus1:$y))),
+                  (XLenVT GPR:$rs1), (XLenVT GPR:$rs3)),
+          (CCMOV GPR:$rs1, (ADDI GPR:$x, (NegImm simm12_plus1:$y)), GPR:$rs3)>;
+def : Pat<(select (XLenVT (setne (XLenVT GPR:$x), (XLenVT GPR:$y))),
+                  (XLenVT GPR:$rs1), (XLenVT GPR:$rs3)),
+          (CCMOV GPR:$rs1, (XOR GPR:$x, GPR:$y), GPR:$rs3)>;
+def : Pat<(select (XLenVT (seteq (XLenVT GPR:$rs2), (XLenVT 0))),
+                  (XLenVT GPR:$rs3), (XLenVT GPR:$rs1)),
+          (CCMOV GPR:$rs1, GPR:$rs2, GPR:$rs3)>;
+def : Pat<(select (XLenVT (seteq (XLenVT GPR:$x), (XLenVT simm12_plus1:$y))),
+                  (XLenVT GPR:$rs3), (XLenVT GPR:$rs1)),
+          (CCMOV GPR:$rs1, (ADDI GPR:$x, (NegImm simm12_plus1:$y)), GPR:$rs3)>;
+def : Pat<(select (XLenVT (seteq (XLenVT GPR:$x), (XLenVT GPR:$y))),
+                  (XLenVT GPR:$rs3), (XLenVT GPR:$rs1)),
+          (CCMOV GPR:$rs1, (XOR GPR:$x, GPR:$y), GPR:$rs3)>;
+def : Pat<(select (XLenVT (setuge (XLenVT GPR:$x), (XLenVT GPR:$y))),
+                  (XLenVT GPR:$rs3), (XLenVT GPR:$rs1)),
+          (CCMOV GPR:$rs1, (SLTU GPR:$x, GPR:$y), GPR:$rs3)>;
+def : Pat<(select (XLenVT (setge (XLenVT GPR:$x), (XLenVT GPR:$y))),
+                  (XLenVT GPR:$rs3), (XLenVT GPR:$rs1)),
+          (CCMOV GPR:$rs1, (SLT GPR:$x, GPR:$y), GPR:$rs3)>;
+def : Pat<(select (XLenVT (setle (XLenVT GPR:$y), (XLenVT GPR:$x))),
+                  (XLenVT GPR:$rs3), (XLenVT GPR:$rs1)),
+          (CCMOV GPR:$rs1, (SLT GPR:$x, GPR:$y), GPR:$rs3)>;
+def : Pat<(select (XLenVT GPR:$rs2), (XLenVT GPR:$rs1), (XLenVT GPR:$rs3)),
+          (CCMOV GPR:$rs1, GPR:$rs2, GPR:$rs3)>;
+}
+
+let Predicates = [HasVendorMIPSLoadStorePairs], hasSideEffects = 0, DecoderNamespace = "Xmipslsp" in {
+def LWP : LWPFormat<(outs GPR:$rd1, GPR:$rd2), (ins GPR:$rs1, uimm7_lsb00:$imm7),
+                    "mips.lwp", "$rd1, $rd2, ${imm7}(${rs1})">,
+                    Sched<[WriteLDW, WriteLDW, ReadMemBase]> {
+let mayLoad = 1;
+let mayStore = 0;
+}
+def LDP : LDPFormat<(outs GPR:$rd1, GPR:$rd2), (ins GPR:$rs1, uimm7_lsb000:$imm7),
+                    "mips.ldp", "$rd1, $rd2, ${imm7}(${rs1})">,
+                    Sched<[WriteLDD, WriteLDD, ReadMemBase]> {
+let mayLoad = 1;
+let mayStore = 0;
+}
+def SWP : SWPFormat<(outs), (ins GPR:$rs2, GPR:$rs3, GPR:$rs1, uimm7_lsb00:$imm7),
+                    "mips.swp", "$rs2, $rs3, ${imm7}(${rs1})">,
+                    Sched<[WriteSTW, ReadStoreData, ReadStoreData, ReadMemBase]> {
+let mayLoad = 0;
+let mayStore = 1;
+}
+def SDP : SDPFormat<(outs), (ins GPR:$rs2, GPR:$rs3, GPR:$rs1, uimm7_lsb000:$imm7),
+                    "mips.sdp", "$rs2, $rs3, ${imm7}(${rs1})">,
+                    Sched<[WriteSTD, ReadStoreData, ReadStoreData, ReadMemBase]> {
+let mayLoad = 0;
+let mayStore = 1;
+}
+}

llvm/lib/Target/RISCV/RISCVProcessors.td

@@ -116,7 +116,9 @@ def MIPS_P8700 : RISCVProcessorModel<"mips-p8700",
                                       FeatureStdExtZba,
                                       FeatureStdExtZbb,
                                       FeatureStdExtZifencei,
-                                      FeatureStdExtZicsr],
+                                      FeatureStdExtZicsr,
+                                      FeatureVendorMIPSCMove,
+                                      FeatureVendorMIPSLoadStorePairs],
                                      [TuneMIPSP8700]>;
 
 def ROCKET_RV32 : RISCVProcessorModel<"rocket-rv32",

llvm/lib/Target/RISCV/RISCVSubtarget.cpp

@@ -62,6 +62,15 @@ static cl::opt<unsigned> RISCVMinimumJumpTableEntries(
     "riscv-min-jump-table-entries", cl::Hidden,
     cl::desc("Set minimum number of entries to use a jump table on RISCV"));
 
+static cl::opt<bool>
+    UseLoadStorePairsOpt("riscv-load-store-pairs",
+                         cl::desc("RISCV: Optimize for load-store bonding"),
+                         cl::init(false), cl::Hidden);
+
+static cl::opt<bool>
+    UseCCMovInsn("riscv-ccmov", cl::desc("RISCV: Use 'mips.ccmov' instruction"),
+                 cl::init(true), cl::Hidden);
+
 void RISCVSubtarget::anchor() {}
 
 RISCVSubtarget &
@@ -238,3 +247,11 @@ void RISCVSubtarget::overridePostRASchedPolicy(MachineSchedPolicy &Policy,
     Policy.OnlyBottomUp = false;
   }
 }
+
+bool RISCVSubtarget::useLoadStorePairs() const {
+  return UseLoadStorePairsOpt && HasMIPSLSP;
+}
+
+bool RISCVSubtarget::useCCMovInsn() const {
+  return UseCCMovInsn && HasVendorMIPSCMove;
+}

llvm/lib/Target/RISCV/RISCVSubtarget.h

@@ -188,6 +188,8 @@ class RISCVSubtarget : public RISCVGenSubtargetInfo {
   unsigned getXLen() const {
     return is64Bit() ? 64 : 32;
   }
+  bool useLoadStorePairs() const;
+  bool useCCMovInsn() const;
   unsigned getFLen() const {
     if (HasStdExtD)
       return 64;

llvm/lib/Target/RISCV/RISCVTargetMachine.cpp

@@ -389,9 +389,10 @@ class RISCVPassConfig : public TargetPassConfig {
       DAG->addMutation(createStoreClusterDAGMutation(
           DAG->TII, DAG->TRI, /*ReorderWhileClustering=*/true));
     }
+
     return DAG;
   }
-  
+
   void addIRPasses() override;
   bool addPreISel() override;
   void addCodeGenPrepare() override;