[PATCH] D30506: [DAG] Prevent Stale nodes from entering worklist

[Nirav Dave via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rL296668: [DAG] Prevent Stale nodes from entering worklist (authored by niravd).

Changed prior to commit:
  https://reviews.llvm.org/D30506?vs=90217&id=90218#toc

Repository:
  rL LLVM

https://reviews.llvm.org/D30506

Files:
  llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
  llvm/trunk/test/CodeGen/X86/pr32108.ll


Index: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -129,6 +129,9 @@
     /// Add to the worklist making sure its instance is at the back (next to be
     /// processed.)
     void AddToWorklist(SDNode *N) {
+      assert(N->getOpcode() != ISD::DELETED_NODE &&
+             "Deleted Node added to Worklist");
+
       // Skip handle nodes as they can't usefully be combined and confuse the
       // zero-use deletion strategy.
       if (N->getOpcode() == ISD::HANDLENODE)
@@ -12619,10 +12622,13 @@
             Value,
             APInt::getLowBitsSet(Value.getScalarValueSizeInBits(),
                                  ST->getMemoryVT().getScalarSizeInBits()))) {
-      // Re-visit the store if anything changed; SimplifyDemandedBits
-      // will add Value's node back to the worklist if necessary, but
-      // we also need to re-visit the Store node itself.
-      AddToWorklist(N);
+      // Re-visit the store if anything changed and the store hasn't
+      // been merged with another node (N is deleted);
+      // SimplifyDemandedBits will add Value's node back to the
+      // worklist if necessary, but we also need to re-visit the Store
+      // node itself.
+      if (N->getOpcode() != ISD::DELETED_NODE)
+        AddToWorklist(N);
       return SDValue(N, 0);
     }
   }
Index: llvm/trunk/test/CodeGen/X86/pr32108.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/pr32108.ll
+++ llvm/trunk/test/CodeGen/X86/pr32108.ll
@@ -0,0 +1,20 @@
+; RUN: llc -march=x86-64 %s -o -
+
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @autogen_SD1794() {
+BB:
+  %Cmp45 = icmp slt <4 x i32> undef, undef
+  br label %CF243
+
+CF243:                                            ; preds = %CF243, %BB
+  br i1 undef, label %CF243, label %CF257
+
+CF257:                                            ; preds = %CF243
+  %Shuff144 = shufflevector <4 x i1> undef, <4 x i1> %Cmp45, <4 x i32> <i32 undef, i32 undef, i32 5, i32 undef>
+  br label %CF244
+
+CF244:                                            ; preds = %CF244, %CF257
+  %Shuff182 = shufflevector <4 x i1> %Shuff144, <4 x i1> zeroinitializer, <4 x i32> <i32 3, i32 5, i32 7, i32 undef>
+  br label %CF244
+}


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