[PATCH] D33633: [DAGCombine] Unchecked calls to DAGCombiner::*ExtPromoteOperand

[Jacob Young via Phabricator via llvm-commits]

jacobly created this revision.

Other calls to DAGCombiner::*PromoteOperand check the result, but here it could cause an assertion in getNode. Falling back to any extend in this case instead of failing outright seems correct to me.


https://reviews.llvm.org/D33633

Files:
  lib/CodeGen/SelectionDAG/DAGCombiner.cpp


Index: lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1027,13 +1027,13 @@
   switch (Opc) {
   default: break;
   case ISD::AssertSext:
-    return DAG.getNode(ISD::AssertSext, DL, PVT,
-                       SExtPromoteOperand(Op.getOperand(0), PVT),
-                       Op.getOperand(1));
+    if (SDValue Op0 = SExtPromoteOperand(Op.getOperand(0), PVT))
+      return DAG.getNode(ISD::AssertSext, DL, PVT, Op0, Op.getOperand(1));
+    break;
   case ISD::AssertZext:
-    return DAG.getNode(ISD::AssertZext, DL, PVT,
-                       ZExtPromoteOperand(Op.getOperand(0), PVT),
-                       Op.getOperand(1));
+    if (SDValue Op0 = ZExtPromoteOperand(Op.getOperand(0), PVT))
+      return DAG.getNode(ISD::AssertZext, DL, PVT, Op0, Op.getOperand(1));
+    break;
   case ISD::Constant: {
     unsigned ExtOpc =
       Op.getValueType().isByteSized() ? ISD::SIGN_EXTEND : ISD::ZERO_EXTEND;


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