Remove 'unwinds to' support from mainline. This patch undoes r47802 r47989

r48047 r48084 r48085 r48086 r48088 r48096 r48099 r48109 and r48123.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50265 91177308-0d34-0410-b5e6-96231b3b80d8

12 files changed, 21 insertions, 103 deletions

diff --git a/lib/Transforms/IPO/PruneEH.cpp b/lib/Transforms/IPO/PruneEH.cpp
index 1b9aefc582..0181605256 100644
--- a/lib/Transforms/IPO/PruneEH.cpp
+++ b/lib/Transforms/IPO/PruneEH.cpp
@@ -31,7 +31,6 @@ using namespace llvm;
 
 STATISTIC(NumRemoved, "Number of invokes removed");
 STATISTIC(NumUnreach, "Number of noreturn calls optimized");
-STATISTIC(NumBBUnwind, "Number of unwind dest removed from blocks");
 
 namespace {
   struct VISIBILITY_HIDDEN PruneEH : public CallGraphSCCPass {
@@ -152,8 +151,6 @@ bool PruneEH::runOnSCC(const std::vector<CallGraphNode *> &SCC) {
 bool PruneEH::SimplifyFunction(Function *F) {
   bool MadeChange = false;
   for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
-    bool couldUnwind = false;
-
     if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator()))
       if (II->doesNotThrow()) {
         SmallVector<Value*, 8> Args(II->op_begin()+3, II->op_end());
@@ -183,12 +180,10 @@ bool PruneEH::SimplifyFunction(Function *F) {
 
         ++NumRemoved;
         MadeChange = true;
-      } else {
-        couldUnwind = true;
       }
 
     for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; )
-      if (CallInst *CI = dyn_cast<CallInst>(I++)) {
+      if (CallInst *CI = dyn_cast<CallInst>(I++))
         if (CI->doesNotReturn() && !isa<UnreachableInst>(I)) {
           // This call calls a function that cannot return.  Insert an
           // unreachable instruction after it and simplify the code.  Do this
@@ -204,19 +199,9 @@ bool PruneEH::SimplifyFunction(Function *F) {
           MadeChange = true;
           ++NumUnreach;
           break;
-        } else if (!CI->doesNotThrow()) {
-          couldUnwind = true;
         }
-      }
-
-    // Strip 'unwindTo' off of BBs that have no calls/invokes without nounwind.
-    if (!couldUnwind && BB->getUnwindDest()) {
-      MadeChange = true;
-      ++NumBBUnwind;
-      BB->getUnwindDest()->removePredecessor(BB, false, true);
-      BB->setUnwindDest(NULL);
-    }
   }
+
   return MadeChange;
 }
 
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index f51f02da67..f061d497ea 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -11180,15 +11180,12 @@ static void AddReachableCodeToWorklist(BasicBlock *BB,
 
     // Recursively visit successors.  If this is a branch or switch on a
     // constant, only visit the reachable successor.
-    if (BB->getUnwindDest())
-      Worklist.push_back(BB->getUnwindDest());
     TerminatorInst *TI = BB->getTerminator();
     if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
       if (BI->isConditional() && isa<ConstantInt>(BI->getCondition())) {
         bool CondVal = cast<ConstantInt>(BI->getCondition())->getZExtValue();
         BasicBlock *ReachableBB = BI->getSuccessor(!CondVal);
-        if (ReachableBB != BB->getUnwindDest())
-          Worklist.push_back(ReachableBB);
+        Worklist.push_back(ReachableBB);
         continue;
       }
     } else if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {
@@ -11197,8 +11194,7 @@ static void AddReachableCodeToWorklist(BasicBlock *BB,
         for (unsigned i = 1, e = SI->getNumSuccessors(); i != e; ++i)
           if (SI->getCaseValue(i) == Cond) {
             BasicBlock *ReachableBB = SI->getSuccessor(i);
-            if (ReachableBB != BB->getUnwindDest())
-              Worklist.push_back(ReachableBB);
+            Worklist.push_back(ReachableBB);
             continue;
           }
         
diff --git a/lib/Transforms/Scalar/LoopUnroll.cpp b/lib/Transforms/Scalar/LoopUnroll.cpp
index 1962c14d5d..18acb03b1b 100644
--- a/lib/Transforms/Scalar/LoopUnroll.cpp
+++ b/lib/Transforms/Scalar/LoopUnroll.cpp
@@ -405,14 +405,10 @@ bool LoopUnroll::unrollLoop(Loop *L, unsigned Count, unsigned Threshold) {
     }
     
     // Remap all instructions in the most recent iteration
-    for (unsigned i = 0; i < NewBlocks.size(); ++i) {
-      BasicBlock *NB = NewBlocks[i];
-      if (BasicBlock *UnwindDest = NB->getUnwindDest())
-        NB->setUnwindDest(cast<BasicBlock>(LastValueMap[UnwindDest]));
-
-      for (BasicBlock::iterator I = NB->begin(), E = NB->end(); I != E; ++I)
+    for (unsigned i = 0; i < NewBlocks.size(); ++i)
+      for (BasicBlock::iterator I = NewBlocks[i]->begin(),
+           E = NewBlocks[i]->end(); I != E; ++I)
         RemapInstruction(I, LastValueMap);
-    }
   }
   
   // The latch block exits the loop.  If there are any PHI nodes in the
diff --git a/lib/Transforms/Scalar/LoopUnswitch.cpp b/lib/Transforms/Scalar/LoopUnswitch.cpp
index 943c50f5f9..4775123530 100644
--- a/lib/Transforms/Scalar/LoopUnswitch.cpp
+++ b/lib/Transforms/Scalar/LoopUnswitch.cpp
@@ -819,14 +819,10 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
   }
 
   // Rewrite the code to refer to itself.
-  for (unsigned i = 0, e = NewBlocks.size(); i != e; ++i) {
-    BasicBlock *NB = NewBlocks[i];
-    if (BasicBlock *UnwindDest = NB->getUnwindDest())
-      NB->setUnwindDest(cast<BasicBlock>(ValueMap[UnwindDest]));
-
-    for (BasicBlock::iterator I = NB->begin(), E = NB->end(); I != E; ++I)
+  for (unsigned i = 0, e = NewBlocks.size(); i != e; ++i)
+    for (BasicBlock::iterator I = NewBlocks[i]->begin(),
+           E = NewBlocks[i]->end(); I != E; ++I)
       RemapInstruction(I, ValueMap);
-  }
   
   // Rewrite the original preheader to select between versions of the loop.
   BranchInst *OldBR = cast<BranchInst>(OrigPreheader->getTerminator());
diff --git a/lib/Transforms/Scalar/SCCP.cpp b/lib/Transforms/Scalar/SCCP.cpp
index 1ca29a8c03..be071f8b1f 100644
--- a/lib/Transforms/Scalar/SCCP.cpp
+++ b/lib/Transforms/Scalar/SCCP.cpp
@@ -1727,11 +1727,6 @@ bool IPSCCP::runOnModule(Module &M) {
       // If there are any PHI nodes in this successor, drop entries for BB now.
       BasicBlock *DeadBB = BlocksToErase[i];
       while (!DeadBB->use_empty()) {
-        if (BasicBlock *PredBB = dyn_cast<BasicBlock>(DeadBB->use_back())) {
-          PredBB->setUnwindDest(NULL);
-          continue;
-        }
-
         Instruction *I = cast<Instruction>(DeadBB->use_back());
         bool Folded = ConstantFoldTerminator(I->getParent());
         if (!Folded) {
diff --git a/lib/Transforms/Utils/BasicBlockUtils.cpp b/lib/Transforms/Utils/BasicBlockUtils.cpp
index f369d8a343..93a8c8e593 100644
--- a/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -161,7 +161,6 @@ BasicBlock *llvm::SplitBlock(BasicBlock *Old, Instruction *SplitPt, Pass *P) {
   while (isa<PHINode>(SplitIt))
     ++SplitIt;
   BasicBlock *New = Old->splitBasicBlock(SplitIt, Old->getName()+".split");
-  New->setUnwindDest(Old->getUnwindDest());
 
   // The new block lives in whichever loop the old one did.
   if (Loop *L = LI.getLoopFor(Old))
@@ -210,12 +209,8 @@ BasicBlock *llvm::SplitBlockPredecessors(BasicBlock *BB,
   BranchInst *BI = BranchInst::Create(BB, NewBB);
   
   // Move the edges from Preds to point to NewBB instead of BB.
-  for (unsigned i = 0; i != NumPreds; ++i) {
+  for (unsigned i = 0; i != NumPreds; ++i)
     Preds[i]->getTerminator()->replaceUsesOfWith(BB, NewBB);
-    
-    if (Preds[i]->getUnwindDest() == BB)
-      Preds[i]->setUnwindDest(NewBB);
-  }
   
   // Update dominator tree and dominator frontier if available.
   DominatorTree *DT = P ? P->getAnalysisToUpdate<DominatorTree>() : 0;
diff --git a/lib/Transforms/Utils/CloneFunction.cpp b/lib/Transforms/Utils/CloneFunction.cpp
index ca63399c81..54c6a809da 100644
--- a/lib/Transforms/Utils/CloneFunction.cpp
+++ b/lib/Transforms/Utils/CloneFunction.cpp
@@ -34,7 +34,6 @@ BasicBlock *llvm::CloneBasicBlock(const BasicBlock *BB,
                                   ClonedCodeInfo *CodeInfo) {
   BasicBlock *NewBB = BasicBlock::Create("", F);
   if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix);
-  NewBB->setUnwindDest(const_cast<BasicBlock*>(BB->getUnwindDest()));
 
   bool hasCalls = false, hasDynamicAllocas = false, hasStaticAllocas = false;
   
@@ -108,15 +107,10 @@ void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
   // references as we go.  This uses ValueMap to do all the hard work.
   //
   for (Function::iterator BB = cast<BasicBlock>(ValueMap[OldFunc->begin()]),
-         BE = NewFunc->end(); BB != BE; ++BB) {
-    // Fix up the unwind destination.
-    if (BasicBlock *UnwindDest = BB->getUnwindDest())
-      BB->setUnwindDest(cast<BasicBlock>(ValueMap[UnwindDest]));
-
+         BE = NewFunc->end(); BB != BE; ++BB)
     // Loop over all instructions, fixing each one as we find it...
     for (BasicBlock::iterator II = BB->begin(); II != BB->end(); ++II)
       RemapInstruction(II, ValueMap);
-  }
 }
 
 /// CloneFunction - Return a copy of the specified function, but without
diff --git a/lib/Transforms/Utils/CloneLoop.cpp b/lib/Transforms/Utils/CloneLoop.cpp
index 7b3359b2f9..d52d79598f 100644
--- a/lib/Transforms/Utils/CloneLoop.cpp
+++ b/lib/Transforms/Utils/CloneLoop.cpp
@@ -130,10 +130,6 @@ Loop *llvm::CloneLoop(Loop *OrigL, LPPassManager  *LPM, LoopInfo *LI,
   for(SmallVector<BasicBlock *, 16>::iterator NBItr = NewBlocks.begin(), 
         NBE = NewBlocks.end();  NBItr != NBE; ++NBItr) {
     BasicBlock *NB = *NBItr;
-
-    if (BasicBlock *UnwindDest = NB->getUnwindDest())
-      NB->setUnwindDest(cast<BasicBlock>(ValueMap[UnwindDest]));
-
     for(BasicBlock::iterator BI = NB->begin(), BE = NB->end(); 
         BI != BE; ++BI) {
       Instruction *Insn = BI;
diff --git a/lib/Transforms/Utils/CloneTrace.cpp b/lib/Transforms/Utils/CloneTrace.cpp
index 968fb5abcc..07111393e2 100644
--- a/lib/Transforms/Utils/CloneTrace.cpp
+++ b/lib/Transforms/Utils/CloneTrace.cpp
@@ -68,11 +68,6 @@ llvm::CloneTrace(const std::vector<BasicBlock*> &origTrace) {
   //Second loop to do the remapping
   for (std::vector<BasicBlock *>::const_iterator BB = clonedTrace.begin(),
     BE = clonedTrace.end(); BB != BE; ++BB) {
-
-    //Remap the unwind destination
-    if (BasicBlock *UnwindDest = (*BB)->getUnwindDest())
-      (*BB)->setUnwindDest(cast<BasicBlock>(ValueMap[UnwindDest]));
-
     for (BasicBlock::iterator I = (*BB)->begin(); I != (*BB)->end(); ++I) {
       //Loop over all the operands of the instruction
       for (unsigned op=0, E = I->getNumOperands(); op != E; ++op) {
diff --git a/lib/Transforms/Utils/InlineFunction.cpp b/lib/Transforms/Utils/InlineFunction.cpp
index 435be0c05c..6c96785aa1 100644
--- a/lib/Transforms/Utils/InlineFunction.cpp
+++ b/lib/Transforms/Utils/InlineFunction.cpp
@@ -203,7 +203,6 @@ bool llvm::InlineFunction(CallSite CS, CallGraph *CG, const TargetData *TD) {
 
   BasicBlock *OrigBB = TheCall->getParent();
   Function *Caller = OrigBB->getParent();
-  BasicBlock *UnwindBB = OrigBB->getUnwindDest();
 
   // GC poses two hazards to inlining, which only occur when the callee has GC:
   //  1. If the caller has no GC, then the callee's GC must be propagated to the
@@ -419,18 +418,6 @@ bool llvm::InlineFunction(CallSite CS, CallGraph *CG, const TargetData *TD) {
       }
     }
 
-  // If we are inlining a function that unwinds into a BB with an unwind dest,
-  // turn the inlined unwinds into branches to the unwind dest.
-  if (InlinedFunctionInfo.ContainsUnwinds && UnwindBB && isa<CallInst>(TheCall))
-    for (Function::iterator BB = FirstNewBlock, E = Caller->end();
-         BB != E; ++BB) {
-      TerminatorInst *Term = BB->getTerminator();
-      if (isa<UnwindInst>(Term)) {
-        BranchInst::Create(UnwindBB, Term);
-        BB->getInstList().erase(Term);
-      }
-    }
-
   // If we are inlining for an invoke instruction, we must make sure to rewrite
   // any inlined 'unwind' instructions into branches to the invoke exception
   // destination, and call instructions into invoke instructions.
diff --git a/lib/Transforms/Utils/LoopSimplify.cpp b/lib/Transforms/Utils/LoopSimplify.cpp
index fc97287f19..8e30e04286 100644
--- a/lib/Transforms/Utils/LoopSimplify.cpp
+++ b/lib/Transforms/Utils/LoopSimplify.cpp
@@ -125,17 +125,18 @@ bool LoopSimplify::runOnFunction(Function &F) {
     if (LI->getLoopFor(BB)) continue;
     
     bool BlockUnreachable = false;
+    TerminatorInst *TI = BB->getTerminator();
 
     // Check to see if any successors of this block are non-loop-header loops
     // that are not the header.
-    for (succ_iterator I = succ_begin(BB), E = succ_end(BB); I != E; ++I) {
+    for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i) {
       // If this successor is not in a loop, BB is clearly ok.
-      Loop *L = LI->getLoopFor(*I);
+      Loop *L = LI->getLoopFor(TI->getSuccessor(i));
       if (!L) continue;
       
       // If the succ is the loop header, and if L is a top-level loop, then this
       // is an entrance into a loop through the header, which is also ok.
-      if (L->getHeader() == *I && L->getParentLoop() == 0)
+      if (L->getHeader() == TI->getSuccessor(i) && L->getParentLoop() == 0)
         continue;
       
       // Otherwise, this is an entrance into a loop from some place invalid.
@@ -153,11 +154,10 @@ bool LoopSimplify::runOnFunction(Function &F) {
     // loop by replacing the terminator.
     
     // Remove PHI entries from the successors.
-    for (succ_iterator I = succ_begin(BB), E = succ_end(BB); I != E; ++I)
-      (*I)->removePredecessor(BB);
+    for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
+      TI->getSuccessor(i)->removePredecessor(BB);
    
     // Add a new unreachable instruction before the old terminator.
-    TerminatorInst *TI = BB->getTerminator();
     new UnreachableInst(TI);
     
     // Delete the dead terminator.
@@ -576,15 +576,12 @@ void LoopSimplify::InsertUniqueBackedgeBlock(Loop *L) {
   }
 
   // Now that all of the PHI nodes have been inserted and adjusted, modify the
-  // backedge blocks to branch to the BEBlock instead of the header.
+  // backedge blocks to just to the BEBlock instead of the header.
   for (unsigned i = 0, e = BackedgeBlocks.size(); i != e; ++i) {
     TerminatorInst *TI = BackedgeBlocks[i]->getTerminator();
     for (unsigned Op = 0, e = TI->getNumSuccessors(); Op != e; ++Op)
       if (TI->getSuccessor(Op) == Header)
         TI->setSuccessor(Op, BEBlock);
-
-    if (BackedgeBlocks[i]->getUnwindDest() == Header)
-      BackedgeBlocks[i]->setUnwindDest(BEBlock);
   }
 
   //===--- Update all analyses which we must preserve now -----------------===//
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index 8b8195ef1e..7f37b45f2d 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -1342,8 +1342,6 @@ bool llvm::SimplifyCFG(BasicBlock *BB) {
       SmallVector<BasicBlock*, 8> UncondBranchPreds;
       SmallVector<BranchInst*, 8> CondBranchPreds;
       for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
-        if ((*PI)->getUnwindDest() == BB) continue;
-
         TerminatorInst *PTI = (*PI)->getTerminator();
         if (BranchInst *BI = dyn_cast<BranchInst>(PTI)) {
           if (BI->isUnconditional())
@@ -1408,14 +1406,8 @@ bool llvm::SimplifyCFG(BasicBlock *BB) {
     SmallVector<BasicBlock*, 8> Preds(pred_begin(BB), pred_end(BB));
     while (!Preds.empty()) {
       BasicBlock *Pred = Preds.back();
-
-      if (Pred->getUnwindDest() == BB) {
-        Pred->setUnwindDest(NULL);
-        Changed = true;
-      }
-
       if (BranchInst *BI = dyn_cast<BranchInst>(Pred->getTerminator())) {
-        if (BI->isUnconditional() && BI->getSuccessor(0) == BB) {
+        if (BI->isUnconditional()) {
           Pred->getInstList().pop_back();  // nuke uncond branch
           new UnwindInst(Pred);            // Use unwind.
           Changed = true;
@@ -1840,7 +1832,6 @@ bool llvm::SimplifyCFG(BasicBlock *BB) {
 
   BasicBlock *OnlySucc = 0;
   if (OnlyPred && OnlyPred != BB &&    // Don't break self loops
-      OnlyPred->getUnwindDest() != BB &&
       OnlyPred->getTerminator()->getOpcode() != Instruction::Invoke) {
     // Check to see if there is only one distinct successor...
     succ_iterator SI(succ_begin(OnlyPred)), SE(succ_end(OnlyPred));
@@ -1852,8 +1843,7 @@ bool llvm::SimplifyCFG(BasicBlock *BB) {
       }
   }
 
-  if (OnlySucc && (BB->getUnwindDest() == OnlyPred->getUnwindDest() ||
-                   !BB->getUnwindDest() || !OnlyPred->getUnwindDest())) {
+  if (OnlySucc) {
     DOUT << "Merging: " << *BB << "into: " << *OnlyPred;
 
     // Resolve any PHI nodes at the start of the block.  They are all
@@ -1873,10 +1863,6 @@ bool llvm::SimplifyCFG(BasicBlock *BB) {
     // Move all definitions in the successor to the predecessor.
     OnlyPred->getInstList().splice(OnlyPred->end(), BB->getInstList());
 
-    // Move the unwind destination block
-    if (!OnlyPred->getUnwindDest() && BB->getUnwindDest())
-      OnlyPred->setUnwindDest(BB->getUnwindDest());
-
     // Make all PHI nodes that referred to BB now refer to Pred as their
     // source.
     BB->replaceAllUsesWith(OnlyPred);