[PATCH] D57317: [DAGCombine] Deduplicate addcarry node using commutativity.

[Amaury SECHET via Phabricator via llvm-commits]

deadalnix updated this revision to Diff 426311.
deadalnix added a comment.
Herald added subscribers: StephenFan, ecnelises, hiraditya.
Herald added a project: All.

Update for the monorepo


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D57317/new/

https://reviews.llvm.org/D57317

Files:
  llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp


Index: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -3033,6 +3033,17 @@
   if (SDValue Combined = visitADDCARRYLike(N1, N0, CarryIn, N))
     return Combined;
 
+  // We want to avoid useless duplication.
+  // TODO: This is done automatically for binary operations. As ADDCARRY is
+  // not a binary operation, this is not really possible to leverage this
+  // existing mechanism for it. However, if more operations require the same
+  // deduplication logic, then it may be worth generalize.
+  SDValue Ops[] = {N1, N0, CarryIn};
+  SDNode *CSENode =
+      DAG.getNodeIfExists(ISD::ADDCARRY, N->getVTList(), Ops, N->getFlags());
+  if (CSENode)
+    return SDValue(CSENode, 0);
+
   return SDValue();
 }
 


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D57317.426311.patch
Type: text/x-patch
Size: 882 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20220501/4f443ff9/attachment.bin>