Taken into account Duncan's comments for r149481 dated by 2nd Feb 2012:

http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20120130/136146.html

Implemented CaseIterator and it solves almost all described issues: we don't need to mix operand/case/successor indexing anymore. Base iterator class is implemented as a template since it may be initialized either from "const SwitchInst*" or from "SwitchInst*".

ConstCaseIt is just a read-only iterator.
CaseIt is read-write iterator; it allows to change case successor and case value.

Usage of iterator allows totally remove resolveXXXX methods. All indexing convertions done automatically inside the iterator's getters.

Main way of iterator usage looks like this:
SwitchInst *SI = ... // intialize it somehow

for (SwitchInst::CaseIt i = SI->caseBegin(), e = SI->caseEnd(); i != e; ++i) {
  BasicBlock *BB = i.getCaseSuccessor();
  ConstantInt *V = i.getCaseValue();
  // Do something.
}

If you want to convert case number to TerminatorInst successor index, just use getSuccessorIndex iterator's method.
If you want initialize iterator from TerminatorInst successor index, use CaseIt::fromSuccessorIndex(...) method.

There are also related changes in llvm-clients: klee and clang.

llvm-svn: 152297

12 files changed, 92 insertions, 89 deletions

diff --git a/llvm/lib/Transforms/IPO/GlobalOpt.cpp b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
index 58ab567bef0..cd0dcbfe729 100644
--- a/llvm/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
@@ -2582,8 +2582,7 @@ bool Evaluator::EvaluateBlock(BasicBlock::iterator CurInst,
         ConstantInt *Val =
           dyn_cast<ConstantInt>(getVal(SI->getCondition()));
         if (!Val) return false;  // Cannot determine.
-        unsigned ValTISucc = SI->resolveSuccessorIndex(SI->findCaseValue(Val));
-        NextBB = SI->getSuccessor(ValTISucc);
+        NextBB = SI->findCaseValue(Val).getCaseSuccessor();
       } else if (IndirectBrInst *IBI = dyn_cast<IndirectBrInst>(CurInst)) {
         Value *Val = getVal(IBI->getAddress())->stripPointerCasts();
         if (BlockAddress *BA = dyn_cast<BlockAddress>(Val))
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index 318256a9b7f..b5dfc8abb13 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -1245,15 +1245,15 @@ Instruction *InstCombiner::visitSwitchInst(SwitchInst &SI) {
     if (I->getOpcode() == Instruction::Add)
       if (ConstantInt *AddRHS = dyn_cast<ConstantInt>(I->getOperand(1))) {
         // change 'switch (X+4) case 1:' into 'switch (X) case -3'
-        unsigned NumCases = SI.getNumCases();
         // Skip the first item since that's the default case.
-        for (unsigned i = 0; i < NumCases; ++i) {
-          ConstantInt* CaseVal = SI.getCaseValue(i);
+        for (SwitchInst::CaseIt i = SI.caseBegin(), e = SI.caseEnd();
+             i != e; ++i) {
+          ConstantInt* CaseVal = i.getCaseValue();
           Constant* NewCaseVal = ConstantExpr::getSub(cast<Constant>(CaseVal),
                                                       AddRHS);
           assert(isa<ConstantInt>(NewCaseVal) &&
                  "Result of expression should be constant");
-          SI.setCaseValue(i, cast<ConstantInt>(NewCaseVal));
+          i.setValue(cast<ConstantInt>(NewCaseVal));
         }
         SI.setCondition(I->getOperand(0));
         Worklist.Add(I);
@@ -1873,9 +1873,10 @@ static bool AddReachableCodeToWorklist(BasicBlock *BB,
     } else if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {
       if (ConstantInt *Cond = dyn_cast<ConstantInt>(SI->getCondition())) {
         // See if this is an explicit destination.
-        for (unsigned i = 0, e = SI->getNumCases(); i != e; ++i)
-          if (SI->getCaseValue(i) == Cond) {
-            BasicBlock *ReachableBB = SI->getCaseSuccessor(i);
+        for (SwitchInst::CaseIt i = SI->caseBegin(), e = SI->caseEnd();
+             i != e; ++i)
+          if (i.getCaseValue() == Cond) {
+            BasicBlock *ReachableBB = i.getCaseSuccessor();
             Worklist.push_back(ReachableBB);
             continue;
           }
diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp
index fe05e3546a6..45e6aff0ee7 100644
--- a/llvm/lib/Transforms/Scalar/GVN.cpp
+++ b/llvm/lib/Transforms/Scalar/GVN.cpp
@@ -2158,10 +2158,11 @@ bool GVN::processInstruction(Instruction *I) {
     Value *SwitchCond = SI->getCondition();
     BasicBlock *Parent = SI->getParent();
     bool Changed = false;
-    for (unsigned i = 0, e = SI->getNumCases(); i != e; ++i) {
-      BasicBlock *Dst = SI->getCaseSuccessor(i);
+    for (SwitchInst::CaseIt i = SI->caseBegin(), e = SI->caseEnd();
+         i != e; ++i) {
+      BasicBlock *Dst = i.getCaseSuccessor();
       if (isOnlyReachableViaThisEdge(Parent, Dst, DT))
-        Changed |= propagateEquality(SwitchCond, SI->getCaseValue(i), Dst);
+        Changed |= propagateEquality(SwitchCond, i.getCaseValue(), Dst);
     }
     return Changed;
   }
diff --git a/llvm/lib/Transforms/Scalar/JumpThreading.cpp b/llvm/lib/Transforms/Scalar/JumpThreading.cpp
index fa25a8fcd77..4ef5298dc0c 100644
--- a/llvm/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/llvm/lib/Transforms/Scalar/JumpThreading.cpp
@@ -1087,8 +1087,7 @@ bool JumpThreading::ProcessThreadableEdges(Value *Cond, BasicBlock *BB,
     else if (BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator()))
       DestBB = BI->getSuccessor(cast<ConstantInt>(Val)->isZero());
     else if (SwitchInst *SI = dyn_cast<SwitchInst>(BB->getTerminator())) {
-      unsigned ValCase = SI->findCaseValue(cast<ConstantInt>(Val));
-      DestBB = SI->getSuccessor(SI->resolveSuccessorIndex(ValCase));
+      DestBB = SI->findCaseValue(cast<ConstantInt>(Val)).getCaseSuccessor();
     } else {
       assert(isa<IndirectBrInst>(BB->getTerminator())
               && "Unexpected terminator");
diff --git a/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp b/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
index 2c75f637f4a..28e07061166 100644
--- a/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
@@ -445,8 +445,9 @@ bool LoopUnswitch::processCurrentLoop() {
         // Do not process same value again and again.
         // At this point we have some cases already unswitched and
         // some not yet unswitched. Let's find the first not yet unswitched one.
-        for (unsigned i = 0; i < NumCases; ++i) {
-          Constant* UnswitchValCandidate = SI->getCaseValue(i);
+        for (SwitchInst::CaseIt i = SI->caseBegin(), e = SI->caseEnd();
+             i != e; ++i) {
+          Constant* UnswitchValCandidate = i.getCaseValue();
           if (!BranchesInfo.isUnswitched(SI, UnswitchValCandidate)) {
             UnswitchVal = UnswitchValCandidate;
             break;
@@ -574,12 +575,13 @@ bool LoopUnswitch::IsTrivialUnswitchCondition(Value *Cond, Constant **Val,
     // this. 
     // Note that we can't trivially unswitch on the default case or
     // on already unswitched cases.
-    for (unsigned i = 0, e = SI->getNumCases(); i != e; ++i) {
+    for (SwitchInst::CaseIt i = SI->caseBegin(), e = SI->caseEnd();
+         i != e; ++i) {
       BasicBlock* LoopExitCandidate;
       if ((LoopExitCandidate = isTrivialLoopExitBlock(currentLoop, 
-                                               SI->getCaseSuccessor(i)))) {
+                                               i.getCaseSuccessor()))) {
         // Okay, we found a trivial case, remember the value that is trivial.
-        ConstantInt* CaseVal = SI->getCaseValue(i);
+        ConstantInt* CaseVal = i.getCaseValue();
 
         // Check that it was not unswitched before, since already unswitched
         // trivial vals are looks trivial too.
@@ -1117,16 +1119,16 @@ void LoopUnswitch::RewriteLoopBodyWithConditionConstant(Loop *L, Value *LIC,
     SwitchInst *SI = dyn_cast<SwitchInst>(U);
     if (SI == 0 || !isa<ConstantInt>(Val)) continue;
     
-    unsigned DeadCase = SI->findCaseValue(cast<ConstantInt>(Val));
+    SwitchInst::CaseIt DeadCase = SI->findCaseValue(cast<ConstantInt>(Val));
     // Default case is live for multiple values.
-    if (DeadCase == SwitchInst::ErrorIndex) continue;
+    if (DeadCase == SI->caseDefault()) continue;
     
     // Found a dead case value.  Don't remove PHI nodes in the 
     // successor if they become single-entry, those PHI nodes may
     // be in the Users list.
 
     BasicBlock *Switch = SI->getParent();
-    BasicBlock *SISucc = SI->getCaseSuccessor(DeadCase);
+    BasicBlock *SISucc = DeadCase.getCaseSuccessor();
     BasicBlock *Latch = L->getLoopLatch();
     
     BranchesInfo.setUnswitched(SI, Val);
@@ -1146,7 +1148,7 @@ void LoopUnswitch::RewriteLoopBodyWithConditionConstant(Loop *L, Value *LIC,
     // Compute the successors instead of relying on the return value
     // of SplitEdge, since it may have split the switch successor
     // after PHI nodes.
-    BasicBlock *NewSISucc = SI->getCaseSuccessor(DeadCase);
+    BasicBlock *NewSISucc = DeadCase.getCaseSuccessor();
     BasicBlock *OldSISucc = *succ_begin(NewSISucc);
     // Create an "unreachable" destination.
     BasicBlock *Abort = BasicBlock::Create(Context, "us-unreachable",
diff --git a/llvm/lib/Transforms/Scalar/SCCP.cpp b/llvm/lib/Transforms/Scalar/SCCP.cpp
index 4274b509d2f..8d0b86606a8 100644
--- a/llvm/lib/Transforms/Scalar/SCCP.cpp
+++ b/llvm/lib/Transforms/Scalar/SCCP.cpp
@@ -564,7 +564,7 @@ void SCCPSolver::getFeasibleSuccessors(TerminatorInst &TI,
       return;
     }
 
-    Succs[SI->resolveSuccessorIndex(SI->findCaseValue(CI))] = true;
+    Succs[SI->findCaseValue(CI).getSuccessorIndex()] = true;
     return;
   }
 
@@ -623,14 +623,7 @@ bool SCCPSolver::isEdgeFeasible(BasicBlock *From, BasicBlock *To) {
     if (CI == 0)
       return !SCValue.isUndefined();
 
-    // Make sure to skip the "default value" which isn't a value
-    for (unsigned i = 0, E = SI->getNumCases(); i != E; ++i)
-      if (SI->getCaseValue(i) == CI) // Found the taken branch.
-        return SI->getCaseSuccessor(i) == To;
-
-    // If the constant value is not equal to any of the branches, we must
-    // execute default branch.
-    return SI->getDefaultDest() == To;
+    return SI->findCaseValue(CI).getCaseSuccessor() == To;
   }
 
   // Just mark all destinations executable!
@@ -1495,12 +1488,12 @@ bool SCCPSolver::ResolvedUndefsIn(Function &F) {
       // If the input to SCCP is actually switch on undef, fix the undef to
       // the first constant.
       if (isa<UndefValue>(SI->getCondition())) {
-        SI->setCondition(SI->getCaseValue(0));
-        markEdgeExecutable(BB, SI->getCaseSuccessor(0));
+        SI->setCondition(SI->caseBegin().getCaseValue());
+        markEdgeExecutable(BB, SI->caseBegin().getCaseSuccessor());
         return true;
       }
 
-      markForcedConstant(SI->getCondition(), SI->getCaseValue(0));
+      markForcedConstant(SI->getCondition(), SI->caseBegin().getCaseValue());
       return true;
     }
   }
diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index 04ef7d7110c..93125df1460 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -313,8 +313,8 @@ void PruningFunctionCloner::CloneBlock(const BasicBlock *BB,
       Cond = dyn_cast_or_null<ConstantInt>(V);
     }
     if (Cond) {     // Constant fold to uncond branch!
-      unsigned CaseIndex = SI->findCaseValue(Cond);
-      BasicBlock *Dest = SI->getSuccessor(SI->resolveSuccessorIndex(CaseIndex));
+      SwitchInst::ConstCaseIt Case = SI->findCaseValue(Cond);
+      BasicBlock *Dest = const_cast<BasicBlock*>(Case.getCaseSuccessor());
       VMap[OldTI] = BranchInst::Create(Dest, NewBB);
       ToClone.push_back(Dest);
       TerminatorDone = true;
diff --git a/llvm/lib/Transforms/Utils/CodeExtractor.cpp b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
index 429919b79a4..e8c0b80c212 100644
--- a/llvm/lib/Transforms/Utils/CodeExtractor.cpp
+++ b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
@@ -617,7 +617,8 @@ emitCallAndSwitchStatement(Function *newFunction, BasicBlock *codeReplacer,
     // of the other successors.
     TheSwitch->setCondition(call);
     TheSwitch->setDefaultDest(TheSwitch->getSuccessor(NumExitBlocks));
-    TheSwitch->removeCase(NumExitBlocks-1);  // Remove redundant case
+    // Remove redundant case
+    TheSwitch->removeCase(SwitchInst::CaseIt(TheSwitch, NumExitBlocks-1));
     break;
   }
 }
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 336d8f63ec2..6ea3b935757 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -106,31 +106,32 @@ bool llvm::ConstantFoldTerminator(BasicBlock *BB, bool DeleteDeadConditions) {
     // If we are switching on a constant, we can convert the switch into a
     // single branch instruction!
     ConstantInt *CI = dyn_cast<ConstantInt>(SI->getCondition());
-    BasicBlock *TheOnlyDest = SI->getDefaultDest();  // The default dest
+    BasicBlock *TheOnlyDest = SI->getDefaultDest();
     BasicBlock *DefaultDest = TheOnlyDest;
 
     // Figure out which case it goes to.
-    for (unsigned i = 0, e = SI->getNumCases(); i != e; ++i) {
+    for (SwitchInst::CaseIt i = SI->caseBegin(), e = SI->caseEnd();
+         i != e; ++i) {
       // Found case matching a constant operand?
-      if (SI->getCaseValue(i) == CI) {
-        TheOnlyDest = SI->getCaseSuccessor(i);
+      if (i.getCaseValue() == CI) {
+        TheOnlyDest = i.getCaseSuccessor();
         break;
       }
 
       // Check to see if this branch is going to the same place as the default
       // dest.  If so, eliminate it as an explicit compare.
-      if (SI->getCaseSuccessor(i) == DefaultDest) {
+      if (i.getCaseSuccessor() == DefaultDest) {
         // Remove this entry.
         DefaultDest->removePredecessor(SI->getParent());
         SI->removeCase(i);
-        --i; --e;  // Don't skip an entry...
+        --i; --e;
         continue;
       }
 
       // Otherwise, check to see if the switch only branches to one destination.
       // We do this by reseting "TheOnlyDest" to null when we find two non-equal
       // destinations.
-      if (SI->getCaseSuccessor(i) != TheOnlyDest) TheOnlyDest = 0;
+      if (i.getCaseSuccessor() != TheOnlyDest) TheOnlyDest = 0;
     }
 
     if (CI && !TheOnlyDest) {
@@ -167,11 +168,13 @@ bool llvm::ConstantFoldTerminator(BasicBlock *BB, bool DeleteDeadConditions) {
     if (SI->getNumCases() == 1) {
       // Otherwise, we can fold this switch into a conditional branch
       // instruction if it has only one non-default destination.
+      SwitchInst::CaseIt FirstCase = SI->caseBegin();
       Value *Cond = Builder.CreateICmpEQ(SI->getCondition(),
-                                         SI->getCaseValue(0), "cond");
+          FirstCase.getCaseValue(), "cond");
 
       // Insert the new branch.
-      Builder.CreateCondBr(Cond, SI->getCaseSuccessor(0), SI->getDefaultDest());
+      Builder.CreateCondBr(Cond, FirstCase.getCaseSuccessor(),
+                           SI->getDefaultDest());
 
       // Delete the old switch.
       SI->eraseFromParent();
diff --git a/llvm/lib/Transforms/Utils/LowerExpectIntrinsic.cpp b/llvm/lib/Transforms/Utils/LowerExpectIntrinsic.cpp
index df8d68ec8ba..0e9cdf55b24 100644
--- a/llvm/lib/Transforms/Utils/LowerExpectIntrinsic.cpp
+++ b/llvm/lib/Transforms/Utils/LowerExpectIntrinsic.cpp
@@ -73,16 +73,16 @@ bool LowerExpectIntrinsic::HandleSwitchExpect(SwitchInst *SI) {
   LLVMContext &Context = CI->getContext();
   Type *Int32Ty = Type::getInt32Ty(Context);
 
-  unsigned caseNo = SI->findCaseValue(ExpectedValue);
+  SwitchInst::CaseIt Case = SI->findCaseValue(ExpectedValue);
   std::vector<Value *> Vec;
   unsigned n = SI->getNumCases();
   Vec.resize(n + 1 + 1); // +1 for MDString and +1 for default case
 
   Vec[0] = MDString::get(Context, "branch_weights");
-  Vec[1] = ConstantInt::get(Int32Ty, SwitchInst::ErrorIndex == caseNo ?
+  Vec[1] = ConstantInt::get(Int32Ty, Case == SI->caseDefault() ?
                             LikelyBranchWeight : UnlikelyBranchWeight);
   for (unsigned i = 0; i < n; ++i) {
-    Vec[i + 1 + 1] = ConstantInt::get(Int32Ty, i == caseNo ?
+    Vec[i + 1 + 1] = ConstantInt::get(Int32Ty, i == Case.getCaseIndex() ?
         LikelyBranchWeight : UnlikelyBranchWeight);
   }
 
diff --git a/llvm/lib/Transforms/Utils/LowerSwitch.cpp b/llvm/lib/Transforms/Utils/LowerSwitch.cpp
index 424f5647742..84029a58731 100644
--- a/llvm/lib/Transforms/Utils/LowerSwitch.cpp
+++ b/llvm/lib/Transforms/Utils/LowerSwitch.cpp
@@ -237,10 +237,10 @@ unsigned LowerSwitch::Clusterify(CaseVector& Cases, SwitchInst *SI) {
   unsigned numCmps = 0;
 
   // Start with "simple" cases
-  for (unsigned i = 0; i < SI->getNumCases(); ++i)
-    Cases.push_back(CaseRange(SI->getCaseValue(i),
-                              SI->getCaseValue(i),
-                              SI->getCaseSuccessor(i)));
+  for (SwitchInst::CaseIt i = SI->caseBegin(), e = SI->caseEnd(); i != e; ++i)
+    Cases.push_back(CaseRange(i.getCaseValue(), i.getCaseValue(),
+                              i.getCaseSuccessor()));
+  
   std::sort(Cases.begin(), Cases.end(), CaseCmp());
 
   // Merge case into clusters
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index a9853a4185e..33694e9dc07 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -480,9 +480,9 @@ GetValueEqualityComparisonCases(TerminatorInst *TI,
                                                       BasicBlock*> > &Cases) {
   if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {
     Cases.reserve(SI->getNumCases());
-    for (unsigned i = 0, e = SI->getNumCases(); i != e; ++i)
-      Cases.push_back(std::make_pair(SI->getCaseValue(i),
-                                     SI->getCaseSuccessor(i)));
+    for (SwitchInst::CaseIt i = SI->caseBegin(), e = SI->caseEnd(); i != e; ++i)
+      Cases.push_back(std::make_pair(i.getCaseValue(),
+                                     i.getCaseSuccessor()));
     return SI->getDefaultDest();
   }
 
@@ -605,10 +605,10 @@ SimplifyEqualityComparisonWithOnlyPredecessor(TerminatorInst *TI,
     DEBUG(dbgs() << "Threading pred instr: " << *Pred->getTerminator()
                  << "Through successor TI: " << *TI);
 
-    for (unsigned i = SI->getNumCases(); i != 0;) {
+    for (SwitchInst::CaseIt i = SI->caseEnd(), e = SI->caseBegin(); i != e;) {
       --i;
-      if (DeadCases.count(SI->getCaseValue(i))) {
-        SI->getCaseSuccessor(i)->removePredecessor(TI->getParent());
+      if (DeadCases.count(i.getCaseValue())) {
+        i.getCaseSuccessor()->removePredecessor(TI->getParent());
         SI->removeCase(i);
       }
     }
@@ -2009,10 +2009,8 @@ static bool SimplifySwitchOnSelect(SwitchInst *SI, SelectInst *Select) {
 
   // Find the relevant condition and destinations.
   Value *Condition = Select->getCondition();
-  unsigned TrueCase = SI->findCaseValue(TrueVal);
-  unsigned FalseCase = SI->findCaseValue(FalseVal);
-  BasicBlock *TrueBB = SI->getSuccessor(SI->resolveSuccessorIndex(TrueCase));
-  BasicBlock *FalseBB = SI->getSuccessor(SI->resolveSuccessorIndex(FalseCase));
+  BasicBlock *TrueBB = SI->findCaseValue(TrueVal).getCaseSuccessor();
+  BasicBlock *FalseBB = SI->findCaseValue(FalseVal).getCaseSuccessor();
 
   // Perform the actual simplification.
   return SimplifyTerminatorOnSelect(SI, Condition, TrueBB, FalseBB);
@@ -2096,7 +2094,7 @@ static bool TryToSimplifyUncondBranchWithICmpInIt(ICmpInst *ICI,
   // Ok, the block is reachable from the default dest.  If the constant we're
   // comparing exists in one of the other edges, then we can constant fold ICI
   // and zap it.
-  if (SI->findCaseValue(Cst) != SwitchInst::ErrorIndex) {
+  if (SI->findCaseValue(Cst) != SI->caseDefault()) {
     Value *V;
     if (ICI->getPredicate() == ICmpInst::ICMP_EQ)
       V = ConstantInt::getFalse(BB->getContext());
@@ -2423,8 +2421,9 @@ bool SimplifyCFGOpt::SimplifyUnreachable(UnreachableInst *UI) {
         }
       }
     } else if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {
-      for (unsigned i = 0, e = SI->getNumCases(); i != e; ++i)
-        if (SI->getCaseSuccessor(i) == BB) {
+      for (SwitchInst::CaseIt i = SI->caseBegin(), e = SI->caseEnd();
+           i != e; ++i)
+        if (i.getCaseSuccessor() == BB) {
           BB->removePredecessor(SI->getParent());
           SI->removeCase(i);
           --i; --e;
@@ -2434,12 +2433,13 @@ bool SimplifyCFGOpt::SimplifyUnreachable(UnreachableInst *UI) {
       // destination and make it the default.
       if (SI->getDefaultDest() == BB) {
         std::map<BasicBlock*, std::pair<unsigned, unsigned> > Popularity;
-        for (unsigned i = 0, e = SI->getNumCases(); i != e; ++i) {
+        for (SwitchInst::CaseIt i = SI->caseBegin(), e = SI->caseEnd();
+             i != e; ++i) {
           std::pair<unsigned, unsigned> &entry =
-              Popularity[SI->getCaseSuccessor(i)];
+              Popularity[i.getCaseSuccessor()];
           if (entry.first == 0) {
             entry.first = 1;
-            entry.second = i;
+            entry.second = i.getCaseIndex();
           } else {
             entry.first++;
           }
@@ -2470,8 +2470,9 @@ bool SimplifyCFGOpt::SimplifyUnreachable(UnreachableInst *UI) {
             for (unsigned i = 0; i != MaxPop-1; ++i)
               MaxBlock->removePredecessor(SI->getParent());
           
-          for (unsigned i = 0, e = SI->getNumCases(); i != e; ++i)
-            if (SI->getCaseSuccessor(i) == MaxBlock) {
+          for (SwitchInst::CaseIt i = SI->caseBegin(), e = SI->caseEnd();
+               i != e; ++i)
+            if (i.getCaseSuccessor() == MaxBlock) {
               SI->removeCase(i);
               --i; --e;
             }
@@ -2517,11 +2518,13 @@ static bool TurnSwitchRangeIntoICmp(SwitchInst *SI, IRBuilder<> &Builder) {
 
   // Make sure all cases point to the same destination and gather the values.
   SmallVector<ConstantInt *, 16> Cases;
-  Cases.push_back(SI->getCaseValue(0));
-  for (unsigned I = 1, E = SI->getNumCases(); I != E; ++I) {
-    if (SI->getCaseSuccessor(I-1) != SI->getCaseSuccessor(I))
+  SwitchInst::CaseIt I = SI->caseBegin();
+  Cases.push_back(I.getCaseValue());
+  SwitchInst::CaseIt PrevI = I++;
+  for (SwitchInst::CaseIt E = SI->caseEnd(); I != E; PrevI = I++) {
+    if (PrevI.getCaseSuccessor() != I.getCaseSuccessor())
       return false;
-    Cases.push_back(SI->getCaseValue(I));
+    Cases.push_back(I.getCaseValue());
   }
   assert(Cases.size() == SI->getNumCases() && "Not all cases gathered");
 
@@ -2539,10 +2542,11 @@ static bool TurnSwitchRangeIntoICmp(SwitchInst *SI, IRBuilder<> &Builder) {
   if (!Offset->isNullValue())
     Sub = Builder.CreateAdd(Sub, Offset, Sub->getName()+".off");
   Value *Cmp = Builder.CreateICmpULT(Sub, NumCases, "switch");
-  Builder.CreateCondBr(Cmp, SI->getCaseSuccessor(0), SI->getDefaultDest());
+  Builder.CreateCondBr(
+      Cmp, SI->caseBegin().getCaseSuccessor(), SI->getDefaultDest());
 
   // Prune obsolete incoming values off the successor's PHI nodes.
-  for (BasicBlock::iterator BBI = SI->getCaseSuccessor(0)->begin();
+  for (BasicBlock::iterator BBI = SI->caseBegin().getCaseSuccessor()->begin();
        isa<PHINode>(BBI); ++BBI) {
     for (unsigned I = 0, E = SI->getNumCases()-1; I != E; ++I)
       cast<PHINode>(BBI)->removeIncomingValue(SI->getParent());
@@ -2562,22 +2566,22 @@ static bool EliminateDeadSwitchCases(SwitchInst *SI) {
 
   // Gather dead cases.
   SmallVector<ConstantInt*, 8> DeadCases;
-  for (unsigned I = 0, E = SI->getNumCases(); I != E; ++I) {
-    if ((SI->getCaseValue(I)->getValue() & KnownZero) != 0 ||
-        (SI->getCaseValue(I)->getValue() & KnownOne) != KnownOne) {
-      DeadCases.push_back(SI->getCaseValue(I));
+  for (SwitchInst::CaseIt I = SI->caseBegin(), E = SI->caseEnd(); I != E; ++I) {
+    if ((I.getCaseValue()->getValue() & KnownZero) != 0 ||
+        (I.getCaseValue()->getValue() & KnownOne) != KnownOne) {
+      DeadCases.push_back(I.getCaseValue());
       DEBUG(dbgs() << "SimplifyCFG: switch case '"
-                   << SI->getCaseValue(I)->getValue() << "' is dead.\n");
+                   << I.getCaseValue() << "' is dead.\n");
     }
   }
 
   // Remove dead cases from the switch.
   for (unsigned I = 0, E = DeadCases.size(); I != E; ++I) {
-    unsigned Case = SI->findCaseValue(DeadCases[I]);
-    assert(Case != SwitchInst::ErrorIndex &&
+    SwitchInst::CaseIt Case = SI->findCaseValue(DeadCases[I]);
+    assert(Case != SI->caseDefault() &&
            "Case was not found. Probably mistake in DeadCases forming.");
     // Prune unused values from PHI nodes.
-    SI->getCaseSuccessor(Case)->removePredecessor(SI->getParent());
+    Case.getCaseSuccessor()->removePredecessor(SI->getParent());
     SI->removeCase(Case);
   }
 
@@ -2626,9 +2630,9 @@ static bool ForwardSwitchConditionToPHI(SwitchInst *SI) {
   typedef DenseMap<PHINode*, SmallVector<int,4> > ForwardingNodesMap;
   ForwardingNodesMap ForwardingNodes;
 
-  for (unsigned I = 0; I < SI->getNumCases(); ++I) { // 0 is the default case.
-    ConstantInt *CaseValue = SI->getCaseValue(I);
-    BasicBlock *CaseDest = SI->getCaseSuccessor(I);
+  for (SwitchInst::CaseIt I = SI->caseBegin(), E = SI->caseEnd(); I != E; ++I) {
+    ConstantInt *CaseValue = I.getCaseValue();
+    BasicBlock *CaseDest = I.getCaseSuccessor();
 
     int PhiIndex;
     PHINode *PHI = FindPHIForConditionForwarding(CaseValue, CaseDest,