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.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152297 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 7 deletions

diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp
index 318256a..b5dfc8a 100644
--- a/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/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;
           }