From: Chris Lattner <sabre@nondot.org>
Date: Tue, 24 Sep 2002 15:52:01 +0000 (+0000)
Subject: - Do not expose Critical Edge breaking mechanics outside the BCE pass, thus
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=f03cafc280716b5f06419b4f1766b1eee742de15;p=oota-llvm.git

- Do not expose Critical Edge breaking mechanics outside the BCE pass, thus
  removing it from Transforms/Local.h and from Transforms/Utils/*


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@3911 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/Utils/CriticalEdge.cpp b/lib/Transforms/Utils/CriticalEdge.cpp
deleted file mode 100644
index a9f4b611e3f..00000000000
--- a/lib/Transforms/Utils/CriticalEdge.cpp
+++ /dev/null
@@ -1,93 +0,0 @@
-//===-- CriticalEdge.cpp - Functions to detect and split critical edges ---===//
-//
-// These functions are here to detect and split critical edges in the CFG.
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/iTerminators.h"
-#include "llvm/iPHINode.h"
-#include "llvm/Analysis/Dominators.h"
-#include "llvm/Support/CFG.h"
-
-// isCriticalEdge - Return true if the specified edge is a critical edge.
-// Critical edges are edges from a block with multiple successors to a block
-// with multiple predecessors.
-//
-bool isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum) {
-  assert(SuccNum < TI->getNumSuccessors() && "Illegal edge specification!");
-  if (TI->getNumSuccessors() <= 1) return false;
-
-  const BasicBlock *Dest = TI->getSuccessor(SuccNum);
-  pred_const_iterator I = pred_begin(Dest), E = pred_end(Dest);
-
-  // If there is more than one predecessor, this is a critical edge...
-  assert(I != E && "No preds, but we have an edge to the block?");
-  ++I;        // Skip one edge due to the incoming arc from TI.
-  return I != E;
-}
-
-// SplitCriticalEdge - Insert a new node node to split the critical edge.  This
-// will update DominatorSet, ImmediateDominator and DominatorTree information if
-// it is available, thus calling this pass will not invalidate either of them.
-//
-void SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, Pass *P) {
-  assert(isCriticalEdge(TI, SuccNum) &&
-         "Cannot break a critical edge, if it isn't a critical edge");
-  BasicBlock *TIBB = TI->getParent();
-
-  // Create a new basic block, linking it into the CFG.
-  BasicBlock *NewBB = new BasicBlock(TIBB->getName()+"_crit_edge");
-  BasicBlock *DestBB = TI->getSuccessor(SuccNum);
-  // Create our unconditional branch...
-  BranchInst *BI = new BranchInst(DestBB);
-  NewBB->getInstList().push_back(BI);
-  
-  // Branch to the new block, breaking the edge...
-  TI->setSuccessor(SuccNum, NewBB);
-
-  // Insert the block into the function... right after the block TI lives in.
-  Function &F = *TIBB->getParent();
-  F.getBasicBlockList().insert(TIBB->getNext(), NewBB);
-
-  // If there are any PHI nodes in DestBB, we need to update them so that they
-  // merge incoming values from NewBB instead of from TIBB.
-  //
-  for (BasicBlock::iterator I = DestBB->begin();
-       PHINode *PN = dyn_cast<PHINode>(&*I); ++I) {
-    // We no longer enter through TIBB, now we come in through NewBB.
-    PN->replaceUsesOfWith(TIBB, NewBB);
-  }
-
-  // Now if we have a pass object, update analysis information.  Currently we
-  // update DominatorSet and DominatorTree information if it's available.
-  //
-  if (P) {
-    // Should we update DominatorSet information?
-    if (DominatorSet *DS = P->getAnalysisToUpdate<DominatorSet>()) {
-      // The blocks that dominate the new one are the blocks that dominate TIBB
-      // plus the new block itself.
-      DominatorSet::DomSetType DomSet = DS->getDominators(TIBB);
-      DomSet.insert(NewBB);  // A block always dominates itself.
-      DS->addBasicBlock(NewBB, DomSet);
-    }
-
-    // Should we update ImmdediateDominator information?
-    if (ImmediateDominators *ID =
-        P->getAnalysisToUpdate<ImmediateDominators>()) {
-      // TIBB is the new immediate dominator for NewBB.  NewBB doesn't dominate
-      // anything.
-      ID->addNewBlock(NewBB, TIBB);
-    }
-
-    // Should we update DominatorTree information?
-    if (DominatorTree *DT = P->getAnalysisToUpdate<DominatorTree>()) {
-      DominatorTree::Node *TINode = DT->getNode(TIBB);
-
-      // The new block is not the immediate dominator for any other nodes, but
-      // TINode is the immediate dominator for the new node.
-      //
-      DT->createNewNode(NewBB, TINode);
-    }
-  }
-}