2 files changed, 13 insertions, 7 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index f64990fe0b4..af2a5d2c1e9 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -1237,11 +1237,17 @@ 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'
-        for (unsigned i = 2, e = SI.getNumOperands(); i != e; i += 2)
-          SI.setOperand(i,
-                   ConstantExpr::getSub(cast<Constant>(SI.getOperand(i)),
-                                                AddRHS));
-        SI.setOperand(0, I->getOperand(0));
+        unsigned NumCases = SI.getNumCases();
+        // Skip the first item since that's the default case.
+        for (unsigned i = 1; i < NumCases; ++i) {
+          ConstantInt* CaseVal = SI.getCaseValue(i);
+          Constant* NewCaseVal = ConstantExpr::getSub(cast<Constant>(CaseVal),
+                                                      AddRHS);
+          assert(isa<ConstantInt>(NewCaseVal) &&
+                 "Result of expression should be constant");
+          SI.setSuccessorValue(i, cast<ConstantInt>(NewCaseVal));
+        }
+        SI.setCondition(I->getOperand(0));
         Worklist.Add(I);
         return &SI;
       }
diff --git a/llvm/lib/Transforms/Utils/LowerSwitch.cpp b/llvm/lib/Transforms/Utils/LowerSwitch.cpp
index ed733d393a1..686178ca01c 100644
--- a/llvm/lib/Transforms/Utils/LowerSwitch.cpp
+++ b/llvm/lib/Transforms/Utils/LowerSwitch.cpp
@@ -277,11 +277,11 @@ void LowerSwitch::processSwitchInst(SwitchInst *SI) {
   BasicBlock *CurBlock = SI->getParent();
   BasicBlock *OrigBlock = CurBlock;
   Function *F = CurBlock->getParent();
-  Value *Val = SI->getOperand(0);  // The value we are switching on...
+  Value *Val = SI->getCondition();  // The value we are switching on...
   BasicBlock* Default = SI->getDefaultDest();
 
   // If there is only the default destination, don't bother with the code below.
-  if (SI->getNumOperands() == 2) {
+  if (SI->getNumCases() == 1) {
     BranchInst::Create(SI->getDefaultDest(), CurBlock);
     CurBlock->getInstList().erase(SI);
     return;