From 8ecffa996aecec8501e03e0c3fa271b84d6fc4d3 Mon Sep 17 00:00:00 2001
From: Devang Patel <dpatel@apple.com>
Date: Fri, 8 Jun 2007 00:02:08 +0000
Subject: [PATCH] Do not preserve ETForest.

llvm-svn: 37506
---
 .../llvm/Transforms/Utils/BasicBlockUtils.h   | 18 +++++------
 .../Transforms/Utils/BreakCriticalEdges.cpp   | 31 +++----------------
 2 files changed, 14 insertions(+), 35 deletions(-)

diff --git a/llvm/include/llvm/Transforms/Utils/BasicBlockUtils.h b/llvm/include/llvm/Transforms/Utils/BasicBlockUtils.h
index 9c49c5e68567..4939111b88b1 100644
--- a/llvm/include/llvm/Transforms/Utils/BasicBlockUtils.h
+++ b/llvm/include/llvm/Transforms/Utils/BasicBlockUtils.h
@@ -61,15 +61,15 @@ bool isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum,
                     bool AllowIdenticalEdges = false);
 
 /// SplitCriticalEdge - If this edge is a critical edge, insert a new node to
-/// split the critical edge.  This will update ETForest, ImmediateDominator,
-/// DominatorTree, and DominatorFrontier information if it is available, thus
-/// calling this pass will not invalidate either of them.  This returns true if
-/// the edge was split, false otherwise.  If MergeIdenticalEdges is true (the
-/// default), *all* edges from TI to the specified successor will be merged into
-/// the same critical edge block.  This is most commonly interesting with switch
-/// instructions, which may have many edges to any one destination.  This
-/// ensures that all edges to that dest go to one block instead of each going to
-/// a different block, but isn't the standard definition of a "critical edge".
+/// split the critical edge.  This will update DominatorTree, and DominatorFrontier 
+/// information if it is available, thus calling this pass will not invalidate 
+/// either of them. This returns true if the edge was split, false otherwise.  
+/// If MergeIdenticalEdges is true (the default), *all* edges from TI to the 
+/// specified successor will be merged into the same critical edge block.  
+/// This is most commonly interesting with switch instructions, which may 
+/// have many edges to any one destination.  This ensures that all edges to that 
+/// dest go to one block instead of each going to a different block, but isn't 
+/// the standard definition of a "critical edge".
 ///
 bool SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, Pass *P = 0,
                        bool MergeIdenticalEdges = false);
diff --git a/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp b/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp
index 6ceea34270f5..af9a114bbebf 100644
--- a/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp
+++ b/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp
@@ -40,7 +40,6 @@ namespace {
     virtual bool runOnFunction(Function &F);
 
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
-      AU.addPreserved<ETForest>();
       AU.addPreserved<DominatorTree>();
       AU.addPreserved<DominanceFrontier>();
       AU.addPreserved<LoopInfo>();
@@ -110,11 +109,11 @@ bool llvm::isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum,
 }
 
 // SplitCriticalEdge - If this edge is a critical edge, insert a new node to
-// split the critical edge.  This will update ETForest, ImmediateDominator,
-// DominatorTree, and DominatorFrontier information if it is available, thus
-// calling this pass will not invalidate any of them.  This returns true if
-// the edge was split, false otherwise.  This ensures that all edges to that
-// dest go to one block instead of each going to a different block.
+// split the critical edge.  This will update DominatorTree, and DominatorFrontier 
+// information if it is available, thus calling this pass will not invalidate 
+// any of them.  This returns true if the edge was split, false otherwise. 
+// This ensures that all edges to that dest go to one block instead of each 
+// going to a different block.
 //
 bool llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, Pass *P,
                              bool MergeIdenticalEdges) {
@@ -181,26 +180,6 @@ bool llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, Pass *P,
   
   bool NewBBDominatesDestBB = true;
   
-  // Update the forest?
-  if (ETForest *EF = P->getAnalysisToUpdate<ETForest>()) {
-    // NewBB is dominated by TIBB.
-    EF->addNewBlock(NewBB, TIBB);
-    
-    // If NewBBDominatesDestBB hasn't been computed yet, do so with EF.
-    if (!OtherPreds.empty()) {
-      while (!OtherPreds.empty() && NewBBDominatesDestBB) {
-        NewBBDominatesDestBB = EF->dominates(DestBB, OtherPreds.back());
-        OtherPreds.pop_back();
-      }
-      OtherPreds.clear();
-    }
-    
-    // If NewBBDominatesDestBB, then NewBB dominates DestBB, otherwise it
-    // doesn't dominate anything.
-    if (NewBBDominatesDestBB)
-      EF->setImmediateDominator(DestBB, NewBB);
-  }
-  
   // Should we update DominatorTree information?
   if (DominatorTree *DT = P->getAnalysisToUpdate<DominatorTree>()) {
     DomTreeNode *TINode = DT->getNode(TIBB);