[PATCH] D60020: [DAGCombiner][X86][SystemZ] Canonicalize SSUBO with immediate RHS to SADDO by negating the immediate.

[Dan Robertson via Phabricator via llvm-commits]

dlrobertson added inline comments.


================
Comment at: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:3047
+  // fold (subox, c) -> (addo x, -c)
+  if (IsSigned && N1C && !N1C->getAPIntValue().isMinSignedValue()) {
+    return DAG.getNode(ISD::SADDO, DL, N->getVTList(), N0,
----------------
I don't think this path would be hit post-D60061 right? Would this be for the case that `opt` is run without `instcombine`?

Also D60061 uses `Constant` and `isNotMinSignedValue`. Is there a reason not to use `N1C->getConstantIntValue()->isNotMinSignedValue` here too? Are there pros/cons to either one?


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D60020/new/

https://reviews.llvm.org/D60020