Substantially improve the DSA code by removing 'forwarding' nodes from

DSGraphs while they are forwarding.  When the last reference to the forwarding
node is dropped, the forwarding node is autodeleted.  This should simplify
removeTriviallyDead nodes, and is only (efficiently) possible because we are
using an ilist of dsnodes now.

llvm-svn: 11175

1 files changed, 5 insertions, 1 deletions

diff --git a/llvm/lib/Analysis/DataStructure/DataStructure.cpp b/llvm/lib/Analysis/DataStructure/DataStructure.cpp
index 57651d78e1e..68530f043ed 100644
--- a/llvm/lib/Analysis/DataStructure/DataStructure.cpp
+++ b/llvm/lib/Analysis/DataStructure/DataStructure.cpp
@@ -46,7 +46,7 @@ namespace {
 using namespace DS;
 
 DSNode *DSNodeHandle::HandleForwarding() const {
-  assert(!N->ForwardNH.isNull() && "Can only be invoked if forwarding!");
+  assert(N->isForwarding() && "Can only be invoked if forwarding!");
 
   // Handle node forwarding here!
   DSNode *Next = N->ForwardNH.getNode();  // Cause recursive shrinkage
@@ -124,6 +124,10 @@ void DSNode::forwardNode(DSNode *To, unsigned Offset) {
   NodeType = DEAD;
   Size = 0;
   Ty = Type::VoidTy;
+
+  // Remove this node from the parent graph's Nodes list.
+  ParentGraph->unlinkNode(this);  
+  ParentGraph = 0;
 }
 
 // addGlobal - Add an entry for a global value to the Globals list.  This also