[llvm] [SelectionDAG] Propagate poison in getNode with two operands if the input is poison. (PR #135387)

[Amy Kwan via llvm-commits]

================
@@ -7601,16 +7604,20 @@ SDValue SelectionDAG::getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
     case ISD::SDIV:
     case ISD::UREM:
     case ISD::SREM:
-      return getUNDEF(VT);       // fold op(arg1, undef) -> undef
+      // fold op(arg1, undef) -> undef, // fold op(arg1, poison) -> poison.
----------------
amy-kwan wrote:

Comment nit.
```suggestion
      // fold op(arg1, undef) -> undef, fold op(arg1, poison) -> poison.
```

https://github.com/llvm/llvm-project/pull/135387