[PATCH] D39117: [mips] Match 'ins' and its' variants with C++ code

[Simon Atanasyan via Phabricator via llvm-commits]

atanasyan added inline comments.


================
Comment at: lib/Target/Mips/MipsSEISelDAGToDAG.cpp:927
+
+    uint64_t Pos = Node->getConstantOperandVal(1);
+    uint64_t Size = Node->getConstantOperandVal(2);
----------------
Now the code below is okay, but i think we can write it a bit more clear. I think the following variant is logically equal to the original one. But I do not force to use it.


```
uint64_t MVT = Node->getConstantOperandVal(0);
uint64_t Pos = Node->getConstantOperandVal(1);
uint64_t Size = Node->getConstantOperandVal(2);

// Size has to be >0 for 'ins', 'dins' and 'dinsu'.
if (!Size)
  return false;

if (Size + Pos > 64)
  return false;

unsigned Opcode = 0;
if (MVT == MVT::i32) {
  if (Pos + Size <= 32)
    Opcode = Mips::INS;
} else {
  if (Pos + Size <= 32)
    Opcode = Mips::DINS;
  else if (Pos < 32)
    Opcode = Mips::DINSM;
  else
    Opcode = Mips::DINSU;
}

if (Opcode) {
  SDValue Ops[4] = {
          MVT, CurDAG->getTargetConstant(Pos, DL, MVT::i32),
          CurDAG->getTargetConstant(Size, DL, MVT::i32), Node->getOperand(3)};

  ReplaceNode(Node, CurDAG->getMachineNode(Opcode, DL, MVT, Ops));
  return true;
}

return false;
```


https://reviews.llvm.org/D39117