remove the now dead condprop pass, PR3906.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86810 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 0 insertions, 294 deletions

diff --git a/lib/Transforms/Scalar/CMakeLists.txt b/lib/Transforms/Scalar/CMakeLists.txt
index e0485182f2..5a92399f67 100644
--- a/lib/Transforms/Scalar/CMakeLists.txt
+++ b/lib/Transforms/Scalar/CMakeLists.txt
@@ -3,7 +3,6 @@ add_llvm_library(LLVMScalarOpts
   ADCE.cpp
   BasicBlockPlacement.cpp
   CodeGenPrepare.cpp
-  CondPropagate.cpp
   ConstantProp.cpp
   DCE.cpp
   DeadStoreElimination.cpp
diff --git a/lib/Transforms/Scalar/CondPropagate.cpp b/lib/Transforms/Scalar/CondPropagate.cpp
deleted file mode 100644
index 8a6c5562eb..0000000000
--- a/lib/Transforms/Scalar/CondPropagate.cpp
+++ /dev/null
@@ -1,289 +0,0 @@
-//===-- CondPropagate.cpp - Propagate Conditional Expressions -------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This pass propagates information about conditional expressions through the
-// program, allowing it to eliminate conditional branches in some cases.
-//
-//===----------------------------------------------------------------------===//
-
-#define DEBUG_TYPE "condprop"
-#include "llvm/Transforms/Scalar.h"
-#include "llvm/Instructions.h"
-#include "llvm/IntrinsicInst.h"
-#include "llvm/Pass.h"
-#include "llvm/Type.h"
-#include "llvm/Transforms/Utils/BasicBlockUtils.h"
-#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/SmallVector.h"
-using namespace llvm;
-
-STATISTIC(NumBrThread, "Number of CFG edges threaded through branches");
-STATISTIC(NumSwThread, "Number of CFG edges threaded through switches");
-
-namespace {
-  struct CondProp : public FunctionPass {
-    static char ID; // Pass identification, replacement for typeid
-    CondProp() : FunctionPass(&ID) {}
-
-    virtual bool runOnFunction(Function &F);
-
-    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
-      AU.addRequiredID(BreakCriticalEdgesID);
-      //AU.addRequired<DominanceFrontier>();
-    }
-
-  private:
-    bool MadeChange;
-    SmallVector<BasicBlock *, 4> DeadBlocks;
-    void SimplifyBlock(BasicBlock *BB);
-    void SimplifyPredecessors(BranchInst *BI);
-    void SimplifyPredecessors(SwitchInst *SI);
-    void RevectorBlockTo(BasicBlock *FromBB, BasicBlock *ToBB);
-    bool RevectorBlockTo(BasicBlock *FromBB, Value *Cond, BranchInst *BI);
-  };
-}
-  
-char CondProp::ID = 0;
-static RegisterPass<CondProp> X("condprop", "Conditional Propagation");
-
-FunctionPass *llvm::createCondPropagationPass() {
-  return new CondProp();
-}
-
-bool CondProp::runOnFunction(Function &F) {
-  bool EverMadeChange = false;
-  DeadBlocks.clear();
-
-  // While we are simplifying blocks, keep iterating.
-  do {
-    MadeChange = false;
-    for (Function::iterator BB = F.begin(), E = F.end(); BB != E;)
-      SimplifyBlock(BB++);
-    EverMadeChange = EverMadeChange || MadeChange;
-  } while (MadeChange);
-
-  if (EverMadeChange) {
-    while (!DeadBlocks.empty()) {
-      BasicBlock *BB = DeadBlocks.back(); DeadBlocks.pop_back();
-      DeleteDeadBlock(BB);
-    }
-  }
-  return EverMadeChange;
-}
-
-void CondProp::SimplifyBlock(BasicBlock *BB) {
-  if (BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator())) {
-    // If this is a conditional branch based on a phi node that is defined in
-    // this block, see if we can simplify predecessors of this block.
-    if (BI->isConditional() && isa<PHINode>(BI->getCondition()) &&
-        cast<PHINode>(BI->getCondition())->getParent() == BB)
-      SimplifyPredecessors(BI);
-
-  } else if (SwitchInst *SI = dyn_cast<SwitchInst>(BB->getTerminator())) {
-    if (isa<PHINode>(SI->getCondition()) &&
-        cast<PHINode>(SI->getCondition())->getParent() == BB)
-      SimplifyPredecessors(SI);
-  }
-
-  // If possible, simplify the terminator of this block.
-  if (ConstantFoldTerminator(BB))
-    MadeChange = true;
-
-  // If this block ends with an unconditional branch and the only successor has
-  // only this block as a predecessor, merge the two blocks together.
-  if (BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator()))
-    if (BI->isUnconditional() && BI->getSuccessor(0)->getSinglePredecessor() &&
-        BB != BI->getSuccessor(0)) {
-      BasicBlock *Succ = BI->getSuccessor(0);
-      
-      // If Succ has any PHI nodes, they are all single-entry PHI's.  Eliminate
-      // them.
-      FoldSingleEntryPHINodes(Succ);
-      
-      // Remove BI.
-      BI->eraseFromParent();
-
-      // Move over all of the instructions.
-      BB->getInstList().splice(BB->end(), Succ->getInstList());
-
-      // Any phi nodes that had entries for Succ now have entries from BB.
-      Succ->replaceAllUsesWith(BB);
-
-      // Succ is now dead, but we cannot delete it without potentially
-      // invalidating iterators elsewhere.  Just insert an unreachable
-      // instruction in it and delete this block later on.
-      new UnreachableInst(BB->getContext(), Succ);
-      DeadBlocks.push_back(Succ);
-      MadeChange = true;
-    }
-}
-
-// SimplifyPredecessors(branches) - We know that BI is a conditional branch
-// based on a PHI node defined in this block.  If the phi node contains constant
-// operands, then the blocks corresponding to those operands can be modified to
-// jump directly to the destination instead of going through this block.
-void CondProp::SimplifyPredecessors(BranchInst *BI) {
-  // TODO: We currently only handle the most trival case, where the PHI node has
-  // one use (the branch), and is the only instruction besides the branch and dbg
-  // intrinsics in the block.
-  PHINode *PN = cast<PHINode>(BI->getCondition());
-
-  if (PN->getNumIncomingValues() == 1) {
-    // Eliminate single-entry PHI nodes.
-    FoldSingleEntryPHINodes(PN->getParent());
-    return;
-  }
-  
-  
-  if (!PN->hasOneUse()) return;
-
-  BasicBlock *BB = BI->getParent();
-  if (&*BB->begin() != PN)
-    return;
-  BasicBlock::iterator BBI = BB->begin();
-  BasicBlock::iterator BBE = BB->end();
-  while (BBI != BBE && isa<DbgInfoIntrinsic>(++BBI)) /* empty */;
-  if (&*BBI != BI)
-    return;
-
-  // Ok, we have this really simple case, walk the PHI operands, looking for
-  // constants.  Walk from the end to remove operands from the end when
-  // possible, and to avoid invalidating "i".
-  for (unsigned i = PN->getNumIncomingValues(); i != 0; --i) {
-    Value *InVal = PN->getIncomingValue(i-1);
-    if (!RevectorBlockTo(PN->getIncomingBlock(i-1), InVal, BI))
-      continue;
-
-    ++NumBrThread;
-
-    // If there were two predecessors before this simplification, or if the
-    // PHI node contained all the same value except for the one we just
-    // substituted, the PHI node may be deleted.  Don't iterate through it the
-    // last time.
-    if (BI->getCondition() != PN) return;
-  }
-}
-
-// SimplifyPredecessors(switch) - We know that SI is switch based on a PHI node
-// defined in this block.  If the phi node contains constant operands, then the
-// blocks corresponding to those operands can be modified to jump directly to
-// the destination instead of going through this block.
-void CondProp::SimplifyPredecessors(SwitchInst *SI) {
-  // TODO: We currently only handle the most trival case, where the PHI node has
-  // one use (the branch), and is the only instruction besides the branch and 
-  // dbg intrinsics in the block.
-  PHINode *PN = cast<PHINode>(SI->getCondition());
-  if (!PN->hasOneUse()) return;
-
-  BasicBlock *BB = SI->getParent();
-  if (&*BB->begin() != PN)
-    return;
-  BasicBlock::iterator BBI = BB->begin();
-  BasicBlock::iterator BBE = BB->end();
-  while (BBI != BBE && isa<DbgInfoIntrinsic>(++BBI)) /* empty */;
-  if (&*BBI != SI)
-    return;
-
-  // Ok, we have this really simple case, walk the PHI operands, looking for
-  // constants.  Walk from the end to remove operands from the end when
-  // possible, and to avoid invalidating "i".
-  for (unsigned i = PN->getNumIncomingValues(); i != 0; --i)
-    if (ConstantInt *CI = dyn_cast<ConstantInt>(PN->getIncomingValue(i-1))) {
-      BasicBlock *PredBB = PN->getIncomingBlock(i-1);
-      if (isa<BranchInst>(PredBB->getTerminator())) {
-        // If we have a constant, forward the edge from its current to its
-        // ultimate destination.
-        unsigned DestCase = SI->findCaseValue(CI);
-        RevectorBlockTo(PredBB, SI->getSuccessor(DestCase));
-        ++NumSwThread;
-
-        // If there were two predecessors before this simplification, or if the
-        // PHI node contained all the same value except for the one we just
-        // substituted, the PHI node may be deleted.  Don't iterate through it the
-        // last time.
-        if (SI->getCondition() != PN) return;
-      }
-    }
-}
-
-
-// RevectorBlockTo - Revector the unconditional branch at the end of FromBB to
-// the ToBB block, which is one of the successors of its current successor.
-void CondProp::RevectorBlockTo(BasicBlock *FromBB, BasicBlock *ToBB) {
-  BranchInst *FromBr = cast<BranchInst>(FromBB->getTerminator());
-  assert(FromBr->isUnconditional() && "FromBB should end with uncond br!");
-
-  // Get the old block we are threading through.
-  BasicBlock *OldSucc = FromBr->getSuccessor(0);
-
-  // OldSucc had multiple successors. If ToBB has multiple predecessors, then 
-  // the edge between them would be critical, which we already took care of.
-  // If ToBB has single operand PHI node then take care of it here.
-  FoldSingleEntryPHINodes(ToBB);
-
-  // Update PHI nodes in OldSucc to know that FromBB no longer branches to it.
-  OldSucc->removePredecessor(FromBB);
-
-  // Change FromBr to branch to the new destination.
-  FromBr->setSuccessor(0, ToBB);
-
-  MadeChange = true;
-}
-
-bool CondProp::RevectorBlockTo(BasicBlock *FromBB, Value *Cond, BranchInst *BI){
-  BranchInst *FromBr = cast<BranchInst>(FromBB->getTerminator());
-  if (!FromBr->isUnconditional())
-    return false;
-
-  // Get the old block we are threading through.
-  BasicBlock *OldSucc = FromBr->getSuccessor(0);
-
-  // If the condition is a constant, simply revector the unconditional branch at
-  // the end of FromBB to one of the successors of its current successor.
-  if (ConstantInt *CB = dyn_cast<ConstantInt>(Cond)) {
-    BasicBlock *ToBB = BI->getSuccessor(CB->isZero());
-
-    // OldSucc had multiple successors. If ToBB has multiple predecessors, then 
-    // the edge between them would be critical, which we already took care of.
-    // If ToBB has single operand PHI node then take care of it here.
-    FoldSingleEntryPHINodes(ToBB);
-
-    // Update PHI nodes in OldSucc to know that FromBB no longer branches to it.
-    OldSucc->removePredecessor(FromBB);
-
-    // Change FromBr to branch to the new destination.
-    FromBr->setSuccessor(0, ToBB);
-  } else {
-    BasicBlock *Succ0 = BI->getSuccessor(0);
-    // Do not perform transform if the new destination has PHI nodes. The
-    // transform will add new preds to the PHI's.
-    if (isa<PHINode>(Succ0->begin()))
-      return false;
-
-    BasicBlock *Succ1 = BI->getSuccessor(1);
-    if (isa<PHINode>(Succ1->begin()))
-      return false;
-
-    // Insert the new conditional branch.
-    BranchInst::Create(Succ0, Succ1, Cond, FromBr);
-
-    FoldSingleEntryPHINodes(Succ0);
-    FoldSingleEntryPHINodes(Succ1);
-
-    // Update PHI nodes in OldSucc to know that FromBB no longer branches to it.
-    OldSucc->removePredecessor(FromBB);
-
-    // Delete the old branch.
-    FromBr->eraseFromParent();
-  }
-
-  MadeChange = true;
-  return true;
-}
diff --git a/lib/Transforms/Scalar/Scalar.cpp b/lib/Transforms/Scalar/Scalar.cpp
index 5669da0f1a..b54565cb80 100644
--- a/lib/Transforms/Scalar/Scalar.cpp
+++ b/lib/Transforms/Scalar/Scalar.cpp
@@ -26,10 +26,6 @@ void LLVMAddCFGSimplificationPass(LLVMPassManagerRef PM) {
   unwrap(PM)->add(createCFGSimplificationPass());
 }
 
-void LLVMAddCondPropagationPass(LLVMPassManagerRef PM) {
-  unwrap(PM)->add(createCondPropagationPass());
-}
-
 void LLVMAddDeadStoreEliminationPass(LLVMPassManagerRef PM) {
   unwrap(PM)->add(createDeadStoreEliminationPass());
 }