[llvm] Base with add like constant offset (PR #88493)

[Simon Pilgrim via llvm-commits]

================
@@ -5191,6 +5191,9 @@ bool SelectionDAG::isADDLike(SDValue Op) const {
 }
 
 bool SelectionDAG::isBaseWithConstantOffset(SDValue Op) const {
----------------
RKSimon wrote:

Can we not just simplify this function to:
```
bool SelectionDAG::isBaseWithConstantOffset(SDValue Op) const {
  return (Op.getOpcode() == ISD::ADD || isADDLike(Op)) &&
         isa<ConstantSDNode>(Op.getOperand(1));
}
```

https://github.com/llvm/llvm-project/pull/88493