Revert r70645 for now; it's causing a variety of regressions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70661 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 51 insertions, 9 deletions

diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp
index 3d9017d17e..be94c45793 100644
--- a/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -124,6 +124,7 @@ DeleteTriviallyDeadInstructions(SmallPtrSet<Instruction*, 16> &Insts) {
       for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
         if (Instruction *U = dyn_cast<Instruction>(I->getOperand(i)))
           Insts.insert(U);
+      SE->deleteValueFromRecords(I);
       DOUT << "INDVARS: Deleting: " << *I;
       I->eraseFromParent();
       Changed = true;
@@ -307,6 +308,7 @@ void IndVarSimplify::RewriteLoopExitValues(Loop *L,
         // the PHI entirely.  This is safe, because the NewVal won't be variant
         // in the loop, so we don't need an LCSSA phi node anymore.
         if (NumPreds == 1) {
+          SE->deleteValueFromRecords(PN);
           PN->replaceAllUsesWith(ExitVal);
           PN->eraseFromParent();
           break;
diff --git a/lib/Transforms/Scalar/LoopDeletion.cpp b/lib/Transforms/Scalar/LoopDeletion.cpp
index 96b7a5288a..83c25619bf 100644
--- a/lib/Transforms/Scalar/LoopDeletion.cpp
+++ b/lib/Transforms/Scalar/LoopDeletion.cpp
@@ -246,6 +246,13 @@ bool LoopDeletion::runOnLoop(Loop* L, LPPassManager& LPM) {
     DT.eraseNode(*LI);
     if (DF) DF->removeBlock(*LI);
 
+    // Remove instructions that we're deleting from ScalarEvolution.
+    for (BasicBlock::iterator BI = (*LI)->begin(), BE = (*LI)->end();
+         BI != BE; ++BI)
+      SE.deleteValueFromRecords(BI);
+    
+    SE.deleteValueFromRecords(*LI);
+    
     // Remove the block from the reference counting scheme, so that we can
     // delete it freely later.
     (*LI)->dropAllReferences();
diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 7d69dc8333..b940665152 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -253,6 +253,8 @@ void LoopStrengthReduce::DeleteTriviallyDeadInstructions() {
     if (I == 0 || !isInstructionTriviallyDead(I))
       continue;
 
+    SE->deleteValueFromRecords(I);
+
     for (User::op_iterator OI = I->op_begin(), E = I->op_end(); OI != E; ++OI) {
       if (Instruction *U = dyn_cast<Instruction>(*OI)) {
         *OI = 0;
@@ -2128,6 +2130,7 @@ ICmpInst *LoopStrengthReduce::ChangeCompareStride(Loop *L, ICmpInst *Cond,
 
     // Remove the old compare instruction. The old indvar is probably dead too.
     DeadInsts.push_back(cast<Instruction>(CondUse->OperandValToReplace));
+    SE->deleteValueFromRecords(OldCond);
     OldCond->replaceAllUsesWith(Cond);
     OldCond->eraseFromParent();
 
@@ -2248,12 +2251,16 @@ ICmpInst *LoopStrengthReduce::OptimizeSMax(Loop *L, ICmpInst *Cond,
                  Cond->getOperand(0), NewRHS, "scmp", Cond);
 
   // Delete the max calculation instructions.
+  SE->deleteValueFromRecords(Cond);
   Cond->replaceAllUsesWith(NewCond);
   Cond->eraseFromParent();
   Instruction *Cmp = cast<Instruction>(Sel->getOperand(0));
+  SE->deleteValueFromRecords(Sel);
   Sel->eraseFromParent();
-  if (Cmp->use_empty())
+  if (Cmp->use_empty()) {
+    SE->deleteValueFromRecords(Cmp);
     Cmp->eraseFromParent();
+  }
   CondUse->User = NewCond;
   return NewCond;
 }
@@ -2360,6 +2367,7 @@ void LoopStrengthReduce::OptimizeShadowIV(Loop *L) {
       NewPH->addIncoming(NewIncr, PH->getIncomingBlock(Latch));
 
       /* Remove cast operation */
+      SE->deleteValueFromRecords(ShadowUse);
       ShadowUse->replaceAllUsesWith(NewPH);
       ShadowUse->eraseFromParent();
       SI->second.Users.erase(CandidateUI);
@@ -2499,8 +2507,17 @@ bool LoopStrengthReduce::runOnLoop(Loop *L, LPPassManager &LPM) {
     DeleteTriviallyDeadInstructions();
 
   // At this point, it is worth checking to see if any recurrence PHIs are also
-  // dead, so that we can remove them as well.
-  DeleteDeadPHIs(L->getHeader());
+  // dead, so that we can remove them as well. To keep ScalarEvolution
+  // current, use a ValueDeletionListener class.
+  struct LSRListener : public ValueDeletionListener {
+    ScalarEvolution &SE;
+    explicit LSRListener(ScalarEvolution &se) : SE(se) {}
+
+    virtual void ValueWillBeDeleted(Value *V) {
+      SE.deleteValueFromRecords(V);
+    }
+  } VDL(*SE);
+  DeleteDeadPHIs(L->getHeader(), &VDL);
 
   return Changed;
 }
diff --git a/lib/Transforms/Utils/BasicBlockUtils.cpp b/lib/Transforms/Utils/BasicBlockUtils.cpp
index 93764b6d1a..076f89e337 100644
--- a/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -78,8 +78,9 @@ void llvm::FoldSingleEntryPHINodes(BasicBlock *BB) {
 /// DeleteDeadPHIs - Examine each PHI in the given block and delete it if it
 /// is dead. Also recursively delete any operands that become dead as
 /// a result. This includes tracing the def-use list from the PHI to see if
-/// it is ultimately unused or if it reaches an unused cycle.
-void llvm::DeleteDeadPHIs(BasicBlock *BB) {
+/// it is ultimately unused or if it reaches an unused cycle.  If a
+/// ValueDeletionListener is specified, it is notified of the deletions.
+void llvm::DeleteDeadPHIs(BasicBlock *BB, ValueDeletionListener *VDL) {
   // Recursively deleting a PHI may cause multiple PHIs to be deleted
   // or RAUW'd undef, so use an array of WeakVH for the PHIs to delete.
   SmallVector<WeakVH, 8> PHIs;
@@ -89,7 +90,7 @@ void llvm::DeleteDeadPHIs(BasicBlock *BB) {
 
   for (unsigned i = 0, e = PHIs.size(); i != e; ++i)
     if (PHINode *PN = dyn_cast_or_null<PHINode>(PHIs[i].operator Value*()))
-      RecursivelyDeleteDeadPHINode(PN);
+      RecursivelyDeleteDeadPHINode(PN, VDL);
 }
 
 /// MergeBlockIntoPredecessor - Attempts to merge a block into its predecessor,
diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp
index fea739cb46..3b36362bb3 100644
--- a/lib/Transforms/Utils/Local.cpp
+++ b/lib/Transforms/Utils/Local.cpp
@@ -178,10 +178,18 @@ bool llvm::isInstructionTriviallyDead(Instruction *I) {
   return false;
 }
 
+/// ~ValueDeletionListener - A trivial dtor, defined out of line to give the
+/// class a home.
+llvm::ValueDeletionListener::~ValueDeletionListener() {}
+
 /// RecursivelyDeleteTriviallyDeadInstructions - If the specified value is a
 /// trivially dead instruction, delete it.  If that makes any of its operands
 /// trivially dead, delete them too, recursively.
-void llvm::RecursivelyDeleteTriviallyDeadInstructions(Value *V) {
+///
+/// If a ValueDeletionListener is specified, it is notified of instructions that
+/// are actually deleted (before they are actually deleted).
+void llvm::RecursivelyDeleteTriviallyDeadInstructions(Value *V,
+                                                   ValueDeletionListener *VDL) {
   Instruction *I = dyn_cast<Instruction>(V);
   if (!I || !I->use_empty() || !isInstructionTriviallyDead(I))
     return;
@@ -193,6 +201,10 @@ void llvm::RecursivelyDeleteTriviallyDeadInstructions(Value *V) {
     I = DeadInsts.back();
     DeadInsts.pop_back();
 
+    // If the client wanted to know, tell it about deleted instructions.
+    if (VDL)
+      VDL->ValueWillBeDeleted(I);
+    
     // Null out all of the instruction's operands to see if any operand becomes
     // dead as we go.
     for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
@@ -218,8 +230,11 @@ void llvm::RecursivelyDeleteTriviallyDeadInstructions(Value *V) {
 /// either forms a cycle or is terminated by a trivially dead instruction,
 /// delete it.  If that makes any of its operands trivially dead, delete them
 /// too, recursively.
+///
+/// If a ValueDeletionListener is specified, it is notified of instructions that
+/// are actually deleted (before they are actually deleted).
 void
-llvm::RecursivelyDeleteDeadPHINode(PHINode *PN) {
+llvm::RecursivelyDeleteDeadPHINode(PHINode *PN, ValueDeletionListener *VDL) {
 
   // We can remove a PHI if it is on a cycle in the def-use graph
   // where each node in the cycle has degree one, i.e. only one use,
@@ -238,7 +253,7 @@ llvm::RecursivelyDeleteDeadPHINode(PHINode *PN) {
       if (!PHIs.insert(cast<PHINode>(JP))) {
         // Break the cycle and delete the PHI and its operands.
         JP->replaceAllUsesWith(UndefValue::get(JP->getType()));
-        RecursivelyDeleteTriviallyDeadInstructions(JP);
+        RecursivelyDeleteTriviallyDeadInstructions(JP, VDL);
         break;
       }
 }