if (SI1 == SI2) return false; // Can't merge with self!
// It is not safe to merge these two switch instructions if they have a common
- // successor, and if that successor has a PHI node, and if that PHI node has
+ // successor, and if that successor has a PHI node, and if *that* PHI node has
// conflicting incoming values from the two switch blocks.
BasicBlock *SI1BB = SI1->getParent();
BasicBlock *SI2BB = SI2->getParent();
/// AddPredecessorToBlock - Update PHI nodes in Succ to indicate that there will
/// now be entries in it from the 'NewPred' block. The values that will be
/// flowing into the PHI nodes will be the same as those coming in from
-/// ExistPred, and existing predecessor of Succ.
+/// ExistPred, an existing predecessor of Succ.
static void AddPredecessorToBlock(BasicBlock *Succ, BasicBlock *NewPred,
BasicBlock *ExistPred) {
assert(std::find(succ_begin(ExistPred), succ_end(ExistPred), Succ) !=
for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI!=E; ++PI)
if (BranchInst *PBI = dyn_cast<BranchInst>((*PI)->getTerminator()))
if (PBI->isConditional() && SafeToMergeTerminators(BI, PBI)) {
+ BasicBlock *PredBlock = *PI;
if (PBI->getSuccessor(0) == FalseDest ||
PBI->getSuccessor(1) == TrueDest) {
// Invert the predecessors condition test (xor it with true),
if (PBI->getSuccessor(0) == TrueDest ||
PBI->getSuccessor(1) == FalseDest) {
- // Clone Cond into the predecessor basic block, and and the
+ // Clone Cond into the predecessor basic block, and or/and the
// two conditions together.
Instruction *New = Cond->clone();
New->setName(Cond->getName());
Cond->setName(Cond->getName()+".old");
- (*PI)->getInstList().insert(PBI, New);
+ PredBlock->getInstList().insert(PBI, New);
Instruction::BinaryOps Opcode =
PBI->getSuccessor(0) == TrueDest ?
Instruction::Or : Instruction::And;
New, "bothcond", PBI);
PBI->setCondition(NewCond);
if (PBI->getSuccessor(0) == BB) {
- AddPredecessorToBlock(TrueDest, *PI, BB);
+ AddPredecessorToBlock(TrueDest, PredBlock, BB);
PBI->setSuccessor(0, TrueDest);
}
if (PBI->getSuccessor(1) == BB) {
- AddPredecessorToBlock(FalseDest, *PI, BB);
+ AddPredecessorToBlock(FalseDest, PredBlock, BB);
PBI->setSuccessor(1, FalseDest);
}
return SimplifyCFG(BB) | 1;