Transforms/Utils/SimplifyCFG.cpp

1953     Instruction *PBI = &*I;
1954     // Check whether Inst and PBI generate the same value.
1955     if (Inst->isIdenticalTo(PBI)) {
1956       Inst->replaceAllUsesWith(PBI);
1979       if (BranchInst *PBI = dyn_cast<BranchInst>(PB->getTerminator()))
1980         if (PBI->isConditional() &&
1981             (BI->getSuccessor(0) == PBI->getSuccessor(0) ||
1982              BI->getSuccessor(0) == PBI->getSuccessor(1))) {
2057     BranchInst *PBI = dyn_cast<BranchInst>(PredBlock->getTerminator());
2063     if (PBI == 0 || PBI->isUnconditional() ||
2065          !SafeToMergeTerminators(BI, PBI)) ||
2067          !isProfitableToFoldUnconditional(BI, PBI, Cond, PHIs)))
2075       if (PBI->getSuccessor(0) == TrueDest)
2077       else if (PBI->getSuccessor(1) == FalseDest)
2079       else if (PBI->getSuccessor(0) == FalseDest)
2081       else if (PBI->getSuccessor(1) == TrueDest)
2086       if (PBI->getSuccessor(0) != TrueDest && PBI->getSuccessor(1) != TrueDest)
2110       Worklist.push_back(std::make_pair(PBI->getOperand(0), 0));
2133     DEBUG(dbgs() << "FOLDING BRANCH TO COMMON DEST:\n" << *PBI << *BB);
2134     IRBuilder<> Builder(PBI);
2138       Value *NewCond = PBI->getCondition();
2145                                     PBI->getCondition()->getName()+".not");
2148       PBI->setCondition(NewCond);
2149       PBI->swapSuccessors();
2156       PredBlock->getInstList().insert(PBI, NewBonus);
2165     PredBlock->getInstList().insert(PBI, New);
2171         cast<Instruction>(Builder.CreateBinOp(Opc, PBI->getCondition(),
2173       PBI->setCondition(NewCond);
2176       bool PredHasWeights = ExtractBranchMetadata(PBI, PredTrueWeight,
2182       if (PBI->getSuccessor(0) == BB) {
2184           // PBI: br i1 %x, BB, FalseDest
2186           //TrueWeight is TrueWeight for PBI * TrueWeight for BI.
2188           //FalseWeight is FalseWeight for PBI * TotalWeight for BI +
2189           //               TrueWeight for PBI * FalseWeight for BI.
2196         PBI->setSuccessor(0, TrueDest);
2198       if (PBI->getSuccessor(1) == BB) {
2200           // PBI: br i1 %x, TrueDest, BB
2202           //TrueWeight is TrueWeight for PBI * TotalWeight for BI +
2203           //              FalseWeight for PBI * TrueWeight for BI.
2206           //FalseWeight is FalseWeight for PBI * FalseWeight for BI.
2210         PBI->setSuccessor(1, FalseDest);
2217         PBI->setMetadata(LLVMContext::MD_prof,
2221         PBI->setMetadata(LLVMContext::MD_prof, NULL);
2226           PHIs[i]->getIncomingValueForBlock(PBI->getParent()));
2229         if (PBI->getSuccessor(0) == TrueDest) {
2234             cast<Instruction>(Builder.CreateNot(PBI->getCondition(),
2243                                   PBI->getCondition(), MergedCond,
2251                                 PBI->getCondition(), New,
2255               cast<Instruction>(Builder.CreateNot(PBI->getCondition(),
2264         PHIs[i]->setIncomingValue(PHIs[i]->getBasicBlockIndex(PBI->getParent()),
2267       // Change PBI from Conditional to Unconditional.
2268       BranchInst *New_PBI = BranchInst::Create(TrueDest, PBI);
2269       EraseTerminatorInstAndDCECond(PBI);
2270       PBI = New_PBI;
2274     // could replace PBI's branch probabilities with BI's.
2279         I->clone()->insertBefore(PBI);
2288 /// that PBI and BI are both conditional branches, and BI is in one of the
2289 /// successor blocks of PBI - PBI branches to BI.
2290 static bool SimplifyCondBranchToCondBranch(BranchInst *PBI, BranchInst *BI) {
2291   assert(PBI->isConditional() && BI->isConditional());
2297   if (PBI->getCondition() == BI->getCondition() &&
2298       PBI->getSuccessor(0) != PBI->getSuccessor(1)) {
2303       bool CondIsTrue = PBI->getSuccessor(0) == BB;
2318       // Okay, we're going to insert the PHI node.  Since PBI is not the only
2323         if ((PBI = dyn_cast<BranchInst>(P->getTerminator())) &&
2324             PBI != BI && PBI->isConditional() &&
2325             PBI->getCondition() == BI->getCondition() &&
2326             PBI->getSuccessor(0) != PBI->getSuccessor(1)) {
2327           bool CondIsTrue = PBI->getSuccessor(0) == BB;
2356   if (PBI->getSuccessor(0) == BI->getSuccessor(0))
2358   else if (PBI->getSuccessor(0) == BI->getSuccessor(1))
2360   else if (PBI->getSuccessor(1) == BI->getSuccessor(0))
2362   else if (PBI->getSuccessor(1) == BI->getSuccessor(1))
2370   if (PBI->getSuccessor(PBIOp) == BB)
2376   BasicBlock *CommonDest = PBI->getSuccessor(PBIOp);
2387   DEBUG(dbgs() << "FOLDING BRs:" << *PBI->getParent()
2407   DEBUG(dbgs() << *PBI->getParent()->getParent());
2410   // it alone, but modify PBI.
2413   Value *PBICond = PBI->getCondition();
2414   IRBuilder<true, NoFolder> Builder(PBI);
2425   // Modify PBI to branch on the new condition to the new dests.
2426   PBI->setCondition(Cond);
2427   PBI->setSuccessor(0, CommonDest);
2428   PBI->setSuccessor(1, OtherDest);
2430   // Update branch weight for PBI.
2432   bool PredHasWeights = ExtractBranchMetadata(PBI, PredTrueWeight,
2452     PBI->setMetadata(LLVMContext::MD_prof,
2457   // OtherDest may have phi nodes.  If so, add an entry from PBI's
2459   AddPredecessorToBlock(OtherDest, PBI->getParent(), BB);
2461   // We know that the CommonDest already had an edge from PBI to
2463   // entries for BB and PBI's BB.  If so, insert a select to make
2469     unsigned PBBIdx = PN->getBasicBlockIndex(PBI->getParent());
2472       // Insert a select in PBI to pick the right value.
2479   DEBUG(dbgs() << "INTO: " << *PBI->getParent());
2480   DEBUG(dbgs() << *PBI->getParent()->getParent());
4007     if (BranchInst *PBI = dyn_cast<BranchInst>((*PI)->getTerminator()))
4008       if (PBI != BI && PBI->isConditional())
4009         if (SimplifyCondBranchToCondBranch(PBI, BI))