X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FUnreachableBlockElim.cpp;h=8c9631e435bfeb6cd592561e95535ccc31d51abf;hb=dd65ba2dbe6a8cb0fb15818193d011ccd20263a0;hp=c597e5fd7db0ffedde3a737d384e7719643b77bc;hpb=ed532cac7c65a617accdbc1fc7622b1c40110baf;p=oota-llvm.git diff --git a/lib/CodeGen/UnreachableBlockElim.cpp b/lib/CodeGen/UnreachableBlockElim.cpp index c597e5fd7db..8c9631e435b 100644 --- a/lib/CodeGen/UnreachableBlockElim.cpp +++ b/lib/CodeGen/UnreachableBlockElim.cpp @@ -21,32 +21,40 @@ //===----------------------------------------------------------------------===// #include "llvm/CodeGen/Passes.h" -#include "llvm/Constant.h" -#include "llvm/Instructions.h" -#include "llvm/Function.h" -#include "llvm/Pass.h" -#include "llvm/Type.h" +#include "llvm/ADT/DepthFirstIterator.h" +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/CodeGen/MachineDominators.h" #include "llvm/CodeGen/MachineFunctionPass.h" +#include "llvm/CodeGen/MachineLoopInfo.h" #include "llvm/CodeGen/MachineModuleInfo.h" #include "llvm/CodeGen/MachineRegisterInfo.h" -#include "llvm/Support/CFG.h" -#include "llvm/Support/Compiler.h" +#include "llvm/IR/CFG.h" +#include "llvm/IR/Constant.h" +#include "llvm/IR/Dominators.h" +#include "llvm/IR/Function.h" +#include "llvm/IR/Instructions.h" +#include "llvm/IR/Type.h" +#include "llvm/Pass.h" #include "llvm/Target/TargetInstrInfo.h" -#include "llvm/ADT/DepthFirstIterator.h" -#include "llvm/ADT/SmallPtrSet.h" using namespace llvm; namespace { - class VISIBILITY_HIDDEN UnreachableBlockElim : public FunctionPass { - virtual bool runOnFunction(Function &F); + class UnreachableBlockElim : public FunctionPass { + bool runOnFunction(Function &F) override; public: static char ID; // Pass identification, replacement for typeid - UnreachableBlockElim() : FunctionPass(&ID) {} + UnreachableBlockElim() : FunctionPass(ID) { + initializeUnreachableBlockElimPass(*PassRegistry::getPassRegistry()); + } + + void getAnalysisUsage(AnalysisUsage &AU) const override { + AU.addPreserved(); + } }; } char UnreachableBlockElim::ID = 0; -static RegisterPass -X("unreachableblockelim", "Remove unreachable blocks from the CFG"); +INITIALIZE_PASS(UnreachableBlockElim, "unreachableblockelim", + "Remove unreachable blocks from the CFG", false, false) FunctionPass *llvm::createUnreachableBlockEliminationPass() { return new UnreachableBlockElim(); @@ -56,16 +64,15 @@ bool UnreachableBlockElim::runOnFunction(Function &F) { SmallPtrSet Reachable; // Mark all reachable blocks. - for (df_ext_iterator > I = - df_ext_begin(&F, Reachable), E = df_ext_end(&F, Reachable); I != E; ++I) - /* Mark all reachable blocks */; + for (BasicBlock *BB : depth_first_ext(&F, Reachable)) + (void)BB/* Mark all reachable blocks */; // Loop over all dead blocks, remembering them and deleting all instructions // in them. std::vector DeadBlocks; for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) - if (!Reachable.count(I)) { - BasicBlock *BB = I; + if (!Reachable.count(&*I)) { + BasicBlock *BB = &*I; DeadBlocks.push_back(BB); while (PHINode *PN = dyn_cast(BB->begin())) { PN->replaceAllUsesWith(Constant::getNullValue(PN->getType())); @@ -77,58 +84,68 @@ bool UnreachableBlockElim::runOnFunction(Function &F) { } // Actually remove the blocks now. - for (unsigned i = 0, e = DeadBlocks.size(); i != e; ++i) + for (unsigned i = 0, e = DeadBlocks.size(); i != e; ++i) { DeadBlocks[i]->eraseFromParent(); + } - return DeadBlocks.size(); + return !DeadBlocks.empty(); } namespace { - class VISIBILITY_HIDDEN UnreachableMachineBlockElim : - public MachineFunctionPass { - virtual bool runOnMachineFunction(MachineFunction &F); + class UnreachableMachineBlockElim : public MachineFunctionPass { + bool runOnMachineFunction(MachineFunction &F) override; + void getAnalysisUsage(AnalysisUsage &AU) const override; MachineModuleInfo *MMI; public: static char ID; // Pass identification, replacement for typeid - UnreachableMachineBlockElim() : MachineFunctionPass(&ID) {} + UnreachableMachineBlockElim() : MachineFunctionPass(ID) {} }; } char UnreachableMachineBlockElim::ID = 0; -static RegisterPass -Y("unreachable-mbb-elimination", - "Remove unreachable machine basic blocks"); +INITIALIZE_PASS(UnreachableMachineBlockElim, "unreachable-mbb-elimination", + "Remove unreachable machine basic blocks", false, false) + +char &llvm::UnreachableMachineBlockElimID = UnreachableMachineBlockElim::ID; -const PassInfo *const llvm::UnreachableMachineBlockElimID = &Y; +void UnreachableMachineBlockElim::getAnalysisUsage(AnalysisUsage &AU) const { + AU.addPreserved(); + AU.addPreserved(); + MachineFunctionPass::getAnalysisUsage(AU); +} bool UnreachableMachineBlockElim::runOnMachineFunction(MachineFunction &F) { SmallPtrSet Reachable; + bool ModifiedPHI = false; - MMI = getAnalysisToUpdate(); + MMI = getAnalysisIfAvailable(); + MachineDominatorTree *MDT = getAnalysisIfAvailable(); + MachineLoopInfo *MLI = getAnalysisIfAvailable(); // Mark all reachable blocks. - for (df_ext_iterator > - I = df_ext_begin(&F, Reachable), E = df_ext_end(&F, Reachable); - I != E; ++I) - /* Mark all reachable blocks */; + for (MachineBasicBlock *BB : depth_first_ext(&F, Reachable)) + (void)BB/* Mark all reachable blocks */; // Loop over all dead blocks, remembering them and deleting all instructions // in them. std::vector DeadBlocks; for (MachineFunction::iterator I = F.begin(), E = F.end(); I != E; ++I) { - MachineBasicBlock *BB = I; + MachineBasicBlock *BB = &*I; // Test for deadness. if (!Reachable.count(BB)) { DeadBlocks.push_back(BB); + // Update dominator and loop info. + if (MLI) MLI->removeBlock(BB); + if (MDT && MDT->getNode(BB)) MDT->eraseNode(BB); + while (BB->succ_begin() != BB->succ_end()) { MachineBasicBlock* succ = *BB->succ_begin(); MachineBasicBlock::iterator start = succ->begin(); - while (start != succ->end() && - start->getOpcode() == TargetInstrInfo::PHI) { + while (start != succ->end() && start->isPHI()) { for (unsigned i = start->getNumOperands() - 1; i >= 2; i-=2) if (start->getOperand(i).isMBB() && start->getOperand(i).getMBB() == BB) { @@ -145,34 +162,22 @@ bool UnreachableMachineBlockElim::runOnMachineFunction(MachineFunction &F) { } // Actually remove the blocks now. - for (unsigned i = 0, e = DeadBlocks.size(); i != e; ++i) { - MachineBasicBlock *MBB = DeadBlocks[i]; - // If there are any labels in the basic block, unregister them from - // MachineModuleInfo. - if (MMI && !MBB->empty()) { - for (MachineBasicBlock::iterator I = MBB->begin(), - E = MBB->end(); I != E; ++I) { - if (I->isLabel()) - // The label ID # is always operand #0, an immediate. - MMI->InvalidateLabel(I->getOperand(0).getImm()); - } - } - MBB->eraseFromParent(); - } + for (unsigned i = 0, e = DeadBlocks.size(); i != e; ++i) + DeadBlocks[i]->eraseFromParent(); // Cleanup PHI nodes. for (MachineFunction::iterator I = F.begin(), E = F.end(); I != E; ++I) { - MachineBasicBlock *BB = I; + MachineBasicBlock *BB = &*I; // Prune unneeded PHI entries. SmallPtrSet preds(BB->pred_begin(), BB->pred_end()); MachineBasicBlock::iterator phi = BB->begin(); - while (phi != BB->end() && - phi->getOpcode() == TargetInstrInfo::PHI) { + while (phi != BB->end() && phi->isPHI()) { for (unsigned i = phi->getNumOperands() - 1; i >= 2; i-=2) if (!preds.count(phi->getOperand(i).getMBB())) { phi->RemoveOperand(i); phi->RemoveOperand(i-1); + ModifiedPHI = true; } if (phi->getNumOperands() == 3) { @@ -182,9 +187,13 @@ bool UnreachableMachineBlockElim::runOnMachineFunction(MachineFunction &F) { MachineInstr* temp = phi; ++phi; temp->eraseFromParent(); + ModifiedPHI = true; - if (Input != Output) - F.getRegInfo().replaceRegWith(Output, Input); + if (Input != Output) { + MachineRegisterInfo &MRI = F.getRegInfo(); + MRI.constrainRegClass(Input, MRI.getRegClass(Output)); + MRI.replaceRegWith(Output, Input); + } continue; } @@ -195,5 +204,5 @@ bool UnreachableMachineBlockElim::runOnMachineFunction(MachineFunction &F) { F.RenumberBlocks(); - return DeadBlocks.size(); + return (!DeadBlocks.empty() || ModifiedPHI); }