vendor/llvm-project/llvmorg-11-init-20887-g2e10b7a39b9vendor/llvm-project/master

1 files changed, 13 insertions, 2 deletions

diff --git a/llvm/lib/IR/SymbolTableListTraitsImpl.h b/llvm/lib/IR/SymbolTableListTraitsImpl.h
index f399c823d6fb..4283744bd058 100644
--- a/llvm/lib/IR/SymbolTableListTraitsImpl.h
+++ b/llvm/lib/IR/SymbolTableListTraitsImpl.h
@@ -20,6 +20,11 @@
 
 namespace llvm {
 
+/// Notify basic blocks when an instruction is inserted.
+template <typename ParentClass>
+inline void invalidateParentIListOrdering(ParentClass *Parent) {}
+template <> void invalidateParentIListOrdering(BasicBlock *BB);
+
 /// setSymTabObject - This is called when (f.e.) the parent of a basic block
 /// changes.  This requires us to remove all the instruction symtab entries from
 /// the current function and reinsert them into the new function.
@@ -64,6 +69,7 @@ void SymbolTableListTraits<ValueSubClass>::addNodeToList(ValueSubClass *V) {
   assert(!V->getParent() && "Value already in a container!!");
   ItemParentClass *Owner = getListOwner();
   V->setParent(Owner);
+  invalidateParentIListOrdering(Owner);
   if (V->hasName())
     if (ValueSymbolTable *ST = getSymTab(Owner))
       ST->reinsertValue(V);
@@ -81,8 +87,13 @@ void SymbolTableListTraits<ValueSubClass>::removeNodeFromList(
 template <typename ValueSubClass>
 void SymbolTableListTraits<ValueSubClass>::transferNodesFromList(
     SymbolTableListTraits &L2, iterator first, iterator last) {
-  // We only have to do work here if transferring instructions between BBs
-  ItemParentClass *NewIP = getListOwner(), *OldIP = L2.getListOwner();
+  // Transfering nodes, even within the same BB, invalidates the ordering. The
+  // list that we removed the nodes from still has a valid ordering.
+  ItemParentClass *NewIP = getListOwner();
+  invalidateParentIListOrdering(NewIP);
+
+  // Nothing else needs to be done if we're reording nodes within the same list.
+  ItemParentClass *OldIP = L2.getListOwner();
   if (NewIP == OldIP)
     return;