[llvm] [MachineInstr] add insert method for variadic instructions (PR #67699)
Matthias Braun via llvm-commits
llvm-commits at lists.llvm.org
Fri Oct 27 16:04:37 PDT 2023
================
@@ -2475,3 +2475,45 @@ MachineInstr::getFirst5RegLLTs() const {
Reg2, getRegInfo()->getType(Reg2), Reg3, getRegInfo()->getType(Reg3),
Reg4, getRegInfo()->getType(Reg4));
}
+
+void MachineInstr::insert(mop_iterator It, ArrayRef<MachineOperand> Ops) {
+ if (!It || Ops.empty())
+ return;
+
+ // Do one pass to untie operands.
+ DenseMap<unsigned, unsigned> TiedOpIndices;
+ for (const MachineOperand &MO : operands()) {
+ if (MO.isReg() && MO.isTied()) {
+ unsigned OpNo = getOperandNo(&MO);
+ unsigned TiedTo = findTiedOperandIdx(OpNo);
+ TiedOpIndices[OpNo] = TiedTo;
+ untieRegOperand(OpNo);
+ }
+ }
+
+ assert(It->getParent() == this && "iterator points to operand of other inst");
+ const unsigned OpIdx = getOperandNo(It);
+ const unsigned NumOperands = getNumOperands();
+ const unsigned OpsToMove = NumOperands - OpIdx;
+
+ SmallVector<MachineOperand> MovingOps;
+ MovingOps.reserve(OpsToMove);
+
+ for (unsigned I = 0; I < OpsToMove; ++I) {
+ MovingOps.emplace_back(getOperand(OpIdx));
+ removeOperand(OpIdx);
----------------
MatzeB wrote:
Maybe do this in reverse order so we waste less cycles on the `moveOperands()` call within `MachineInstr::removeOperand()`. On that note I wonder if `moveOperands()` would work here as well instead of the `removeOperand` / `addOperand` for `MovingOps` here?
Admittedly it looks like `moveOperands()` doesn't really adjust the `TiedTo` markers so that's why it wouldn't work here?
https://github.com/llvm/llvm-project/pull/67699
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