From b467f8af4125471361468ab91dbedba2abf2e09a Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Wed, 17 Aug 2005 01:54:00 +0000
Subject: [PATCH] make sure to remove a node from the use list of its operands
 when we replace it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22820 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/CodeGen/SelectionDAGNodes.h | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/include/llvm/CodeGen/SelectionDAGNodes.h b/include/llvm/CodeGen/SelectionDAGNodes.h
index 00b94037ad2..930a163848e 100644
--- a/include/llvm/CodeGen/SelectionDAGNodes.h
+++ b/include/llvm/CodeGen/SelectionDAGNodes.h
@@ -614,7 +614,14 @@ protected:
   void MorphNodeTo(unsigned Opc) {
     NodeType = Opc;
     Values.clear();
-    Operands.clear();
+    
+    // Clear the operands list, updating used nodes to remove this from their
+    // use list.
+    while (!Operands.empty()) {
+      SDNode *O = Operands.back().Val;
+      Operands.pop_back();
+      O->removeUser(this);
+    }
   }
   
   void setValueTypes(MVT::ValueType VT) {