[llvm] [RISCV] Add XSfmm pseudo instruction and vset* insertion support (PR #143068)

[Luke Lau via llvm-commits]

================
@@ -1784,6 +1899,83 @@ void RISCVInsertVSETVLI::insertReadVL(MachineBasicBlock &MBB) {
   }
 }
 
+static void shrinkIntervalAndRemoveDeadMI(MachineOperand &MO,
+                                          LiveIntervals *LIS,
+                                          const TargetInstrInfo *TII) {
+  Register Reg = MO.getReg();
+  MO.setReg(RISCV::NoRegister);
+  MO.setIsKill(false);
+
+  if (!LIS)
+    return;
+
+  LiveInterval &LI = LIS->getInterval(Reg);
+
+  // Erase the AVL operand from the instruction.
+  SmallVector<MachineInstr *> DeadMIs;
+  LIS->shrinkToUses(&LI, &DeadMIs);
+  // TODO: Enable this once needVSETVLIPHI is supported.
+  // SmallVector<LiveInterval *> SplitLIs;
+  // LIS->splitSeparateComponents(LI, SplitLIs);
+
+  for (MachineInstr *DeadMI : DeadMIs) {
+    if (!TII->isAddImmediate(*DeadMI, Reg))
+      continue;
+    LIS->RemoveMachineInstrFromMaps(*DeadMI);
+    DeadMI->eraseFromParent();
+  }
+}
+
+bool RISCVInsertVSETVLI::insertVSETMTK(MachineBasicBlock &MBB,
+                                       TKTMMode Mode) const {
+
+  bool Changed = false;
+  for (auto &MI : MBB) {
+    uint64_t TSFlags = MI.getDesc().TSFlags;
+    if (RISCVInstrInfo::isXSfmmVectorConfigTMTKInstr(MI) ||
+        !RISCVII::hasSEWOp(TSFlags) || !RISCVII::hasTWidenOp(TSFlags))
+      continue;
+
+    VSETVLIInfo CurrInfo = computeInfoForInstr(MI);
+
+    if (Mode == VSETTK && !RISCVII::hasTKOp(TSFlags))
+      continue;
+
+    if (Mode == VSETTM && !RISCVII::hasTMOp(TSFlags))
+      continue;
+
+    unsigned OpNum = 0;
+    unsigned Opcode = 0;
+    switch (Mode) {
+    case VSETTK:
+      OpNum = RISCVII::getTKOpNum(MI.getDesc());
+      Opcode = RISCV::PseudoSF_VSETTK;
+      break;
+    case VSETTM:
+      OpNum = RISCVII::getTMOpNum(MI.getDesc());
+      Opcode = RISCV::PseudoSF_VSETTM;
+      break;
+    }
+
+    assert(OpNum && Opcode && "Invalid OpNum or Opcode");
+
+    const MachineOperand &Op = MI.getOperand(OpNum);
+
+    auto TmpMI = BuildMI(MBB, MI, MI.getDebugLoc(), TII->get(Opcode))
+                     .addReg(RISCV::X0, RegState::Define | RegState::Dead)
+                     .addReg(Op.getReg())
+                     .addImm(Log2_32(CurrInfo.getSEW()))
+                     .addImm(Log2_32(CurrInfo.getTWiden()) + 1);
+
+    Changed = true;
+    if (LIS)
+      LIS->InsertMachineInstrInMaps(*TmpMI);
+
+    shrinkIntervalAndRemoveDeadMI(MI.getOperand(OpNum), LIS, TII);
----------------
lukel97 wrote:

If you mark Op as non const can you pass it in here?

https://github.com/llvm/llvm-project/pull/143068