[SDAG] Fix Stale SDNode usage in visitAND

Reorder CombineTo Calls to prevent potential use of deleted node.
Fixes PR32372.

Reviewers: jnspaulsson, RKSimon, uweigand, jonpa

Reviewed By: jonpa

Subscribers: jonpa, llvm-commits

Differential Revision: https://reviews.llvm.org/D31346

llvm-svn: 298920

1 files changed, 4 insertions, 4 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 2263ddc5647..c480c992744 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -3536,6 +3536,10 @@ SDValue DAGCombiner::visitAND(SDNode *N) {
       // If the load type was an EXTLOAD, convert to ZEXTLOAD in order to
       // preserve semantics once we get rid of the AND.
       SDValue NewLoad(Load, 0);
+
+      // Fold the AND away. NewLoad may get replaced immediately.
+      CombineTo(N, NewLoad);
+
       if (Load->getExtensionType() == ISD::EXTLOAD) {
         NewLoad = DAG.getLoad(Load->getAddressingMode(), ISD::ZEXTLOAD,
                               Load->getValueType(0), SDLoc(Load),
@@ -3553,10 +3557,6 @@ SDValue DAGCombiner::visitAND(SDNode *N) {
         }
       }
 
-      // Fold the AND away, taking care not to fold to the old load node if we
-      // replaced it.
-      CombineTo(N, (N0.getNode() == Load) ? NewLoad : N0);
-
       return SDValue(N, 0); // Return N so it doesn't get rechecked!
     }
   }