[DAGCombiner] Fold and/or of NaN SETCC (#135645)

Fold an AND or OR of two NaN SETCC nodes into a single SETCC where
possible. This optimization already exists in InstCombine but adding in
here as well can allow for additional folding if more logical operations
are exposed.

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index d72be35..ab8e182 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -6448,6 +6448,12 @@ static SDValue foldAndOrOfSETCC(SDNode *LogicOp, SelectionDAG &DAG) {
     }
   }
 
+  if (LHS0 == LHS1 && RHS0 == RHS1 && CCL == CCR &&
+      LHS0.getValueType() == RHS0.getValueType() &&
+      ((LogicOp->getOpcode() == ISD::AND && CCL == ISD::SETO) ||
+       (LogicOp->getOpcode() == ISD::OR && CCL == ISD::SETUO)))
+    return DAG.getSetCC(DL, VT, LHS0, RHS0, CCL);
+
   if (TargetPreference == AndOrSETCCFoldKind::None)
     return SDValue();