diff --git a/lib/CodeGen/StackProtector.cpp b/lib/CodeGen/StackProtector.cpp index d90cb39e23f..b3ee152d28b 100644 --- a/lib/CodeGen/StackProtector.cpp +++ b/lib/CodeGen/StackProtector.cpp @@ -150,12 +150,9 @@ bool StackProtector::InsertStackProtectors() { BasicBlock *FailBBDom = 0; // FailBB's dominator. AllocaInst *AI = 0; // Place on stack that stores the stack guard. Value *StackGuardVar = 0; // The stack guard variable. - BasicBlock &Entry = F->getEntryBlock(); for (Function::iterator I = F->begin(), E = F->end(); I != E; ) { BasicBlock *BB = I++; - if (BB->getNumUses() == 0 && BB != &Entry) continue; - ReturnInst *RI = dyn_cast(BB->getTerminator()); if (!RI) continue; @@ -180,6 +177,7 @@ bool StackProtector::InsertStackProtectors() { StackGuardVar = M->getOrInsertGlobal("__stack_chk_guard", PtrTy); } + BasicBlock &Entry = F->getEntryBlock(); Instruction *InsPt = &Entry.front(); AI = new AllocaInst(PtrTy, "StackGuardSlot", InsPt); @@ -192,8 +190,6 @@ bool StackProtector::InsertStackProtectors() { // Create the basic block to jump to when the guard check fails. FailBB = CreateFailBB(); - if (DT) - FailBBDom = DT->isReachableFromEntry(BB) ? BB : 0; } // For each block with a return instruction, convert this: @@ -219,11 +215,12 @@ bool StackProtector::InsertStackProtectors() { // unreachable // Split the basic block before the return instruction. + bool BBIsReachable = (DT && DT->isReachableFromEntry(BB)); BasicBlock *NewBB = BB->splitBasicBlock(RI, "SP_return"); - if (DT && DT->isReachableFromEntry(BB)) { + + if (BBIsReachable) { DT->addNewBlock(NewBB, BB); - if (FailBBDom) - FailBBDom = DT->findNearestCommonDominator(FailBBDom, BB); + FailBBDom = FailBBDom ? DT->findNearestCommonDominator(FailBBDom, BB) :BB; } // Remove default branch instruction to the new BB.