// a select, fixing up PHI nodes and basic blocks.
static void RemoveSwitchAfterSelectConversion(SwitchInst *SI, PHINode *PHI,
Value *SelectValue,
- IRBuilder<> &Builder) {
+ IRBuilder<> &Builder,
+ DomTreeUpdater *DTU) {
BasicBlock *SelectBB = SI->getParent();
while (PHI->getBasicBlockIndex(SelectBB) >= 0)
PHI->removeIncomingValue(SelectBB);
Builder.CreateBr(PHI->getParent());
+ std::vector<DominatorTree::UpdateType> Updates;
+
// Remove the switch.
for (unsigned i = 0, e = SI->getNumSuccessors(); i < e; ++i) {
BasicBlock *Succ = SI->getSuccessor(i);
if (Succ == PHI->getParent())
continue;
Succ->removePredecessor(SelectBB);
+ Updates.push_back({DominatorTree::Delete, SelectBB, Succ});
}
SI->eraseFromParent();
+ if (DTU)
+ DTU->applyUpdatesPermissive(Updates);
}
/// If the switch is only used to initialize one or more
/// phi nodes in a common successor block with only two different
/// constant values, replace the switch with select.
static bool switchToSelect(SwitchInst *SI, IRBuilder<> &Builder,
- const DataLayout &DL,
+ DomTreeUpdater *DTU, const DataLayout &DL,
const TargetTransformInfo &TTI) {
Value *const Cond = SI->getCondition();
PHINode *PHI = nullptr;
Value *SelectValue =
ConvertTwoCaseSwitch(UniqueResults, DefaultResult, Cond, Builder);
if (SelectValue) {
- RemoveSwitchAfterSelectConversion(SI, PHI, SelectValue, Builder);
+ RemoveSwitchAfterSelectConversion(SI, PHI, SelectValue, Builder, DTU);
return true;
}
// The switch couldn't be converted into a select.
if (eliminateDeadSwitchCases(SI, Options.AC, DL))
return requestResimplify();
- if (switchToSelect(SI, Builder, DL, TTI))
+ if (switchToSelect(SI, Builder, DTU, DL, TTI))
return requestResimplify();
if (Options.ForwardSwitchCondToPhi && ForwardSwitchConditionToPHI(SI))