[PATCH] D154885: [DAGCombiner] Limit graph traversal to cap compile times

[Pranav Kant via Phabricator via llvm-commits]

pranavk created this revision.
Herald added a subscriber: hiraditya.
Herald added a project: All.
pranavk requested review of this revision.
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D154885

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
@@ -17627,6 +17627,7 @@
   // can be folded with this one. We should do this to avoid having to keep
   // a copy of the original base pointer.
   SmallVector<SDNode *, 16> OtherUses;
+  const unsigned int MaxSteps = 8192;
   if (isa<ConstantSDNode>(Offset))
     for (SDNode::use_iterator UI = BasePtr->use_begin(),
                               UE = BasePtr->use_end();
@@ -17637,7 +17638,7 @@
       if (Use.getUser() == Ptr.getNode() || Use != BasePtr)
         continue;
 
-      if (SDNode::hasPredecessorHelper(Use.getUser(), Visited, Worklist))
+      if (SDNode::hasPredecessorHelper(Use.getUser(), Visited, Worklist, MaxSteps))
         continue;
 
       if (Use.getUser()->getOpcode() != ISD::ADD &&
@@ -17670,7 +17671,7 @@
   for (SDNode *Use : Ptr->uses()) {
     if (Use == N)
       continue;
-    if (SDNode::hasPredecessorHelper(Use, Visited, Worklist))
+    if (SDNode::hasPredecessorHelper(Use, Visited, Worklist, MaxSteps))
       return false;
 
     // If Ptr may be folded in addressing mode of other use, then it's
@@ -17844,12 +17845,13 @@
     // Check for #2.
     SmallPtrSet<const SDNode *, 32> Visited;
     SmallVector<const SDNode *, 8> Worklist;
+    const unsigned int MaxSteps = 8192;
     // Ptr is predecessor to both N and Op.
     Visited.insert(Ptr.getNode());
     Worklist.push_back(N);
     Worklist.push_back(Op);
-    if (!SDNode::hasPredecessorHelper(N, Visited, Worklist) &&
-        !SDNode::hasPredecessorHelper(Op, Visited, Worklist))
+    if (!SDNode::hasPredecessorHelper(N, Visited, Worklist, MaxSteps) &&
+        !SDNode::hasPredecessorHelper(Op, Visited, Worklist, MaxSteps))
       return Op;
   }
   return nullptr;


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D154885.538796.patch
Type: text/x-patch
Size: 1897 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20230710/7821dbb6/attachment.bin>