X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FUnreachableBlockElim.cpp;h=2e220820b9211d8c815a08f9663bd5dc3b0889bd;hb=285133714f0d995e0e14a77e23a0abe5dfc32d17;hp=57811cab0f67b534599bad61dab6b1f3c353753a;hpb=9200e81a1828f7d3aa59a48c52317e1beeeac0b1;p=oota-llvm.git diff --git a/lib/CodeGen/UnreachableBlockElim.cpp b/lib/CodeGen/UnreachableBlockElim.cpp index 57811cab0f6..2e220820b92 100644 --- a/lib/CodeGen/UnreachableBlockElim.cpp +++ b/lib/CodeGen/UnreachableBlockElim.cpp @@ -21,41 +21,51 @@ //===----------------------------------------------------------------------===// #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" 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((intptr_t)&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(); } bool UnreachableBlockElim::runOnFunction(Function &F) { - std::set Reachable; + 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) + for (df_ext_iterator > I = + df_ext_begin(&F, Reachable), E = df_ext_end(&F, Reachable); I != E; ++I) /* Mark all reachable blocks */; // Loop over all dead blocks, remembering them and deleting all instructions @@ -75,37 +85,49 @@ 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(); } 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((intptr_t)&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) -const PassInfo *const llvm::UnreachableMachineBlockElimID = &Y; +char &llvm::UnreachableMachineBlockElimID = UnreachableMachineBlockElim::ID; + +void UnreachableMachineBlockElim::getAnalysisUsage(AnalysisUsage &AU) const { + AU.addPreserved(); + AU.addPreserved(); + MachineFunctionPass::getAnalysisUsage(AU); +} bool UnreachableMachineBlockElim::runOnMachineFunction(MachineFunction &F) { - std::set Reachable; + SmallPtrSet Reachable; + bool ModifiedPHI = false; + + 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) + for (df_ext_iterator > + I = df_ext_begin(&F, Reachable), E = df_ext_end(&F, Reachable); + I != E; ++I) /* Mark all reachable blocks */; // Loop over all dead blocks, remembering them and deleting all instructions @@ -113,27 +135,30 @@ bool UnreachableMachineBlockElim::runOnMachineFunction(MachineFunction &F) { std::vector DeadBlocks; for (MachineFunction::iterator I = F.begin(), E = F.end(); I != E; ++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) { start->RemoveOperand(i); start->RemoveOperand(i-1); } - + start++; } - + BB->removeSuccessor(BB->succ_begin()); } } @@ -147,11 +172,17 @@ bool UnreachableMachineBlockElim::runOnMachineFunction(MachineFunction &F) { for (MachineFunction::iterator I = F.begin(), E = F.end(); I != E; ++I) { MachineBasicBlock *BB = I; // Prune unneeded PHI entries. - SmallPtrSet preds(BB->pred_begin(), + 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) { unsigned Input = phi->getOperand(1).getReg(); unsigned Output = phi->getOperand(0).getReg(); @@ -159,25 +190,22 @@ bool UnreachableMachineBlockElim::runOnMachineFunction(MachineFunction &F) { MachineInstr* temp = phi; ++phi; temp->eraseFromParent(); + ModifiedPHI = true; + + if (Input != Output) { + MachineRegisterInfo &MRI = F.getRegInfo(); + MRI.constrainRegClass(Input, MRI.getRegClass(Output)); + MRI.replaceRegWith(Output, Input); + } - if (Input != Output) - F.getRegInfo().replaceRegWith(Output, Input); - continue; } - - for (unsigned i = phi->getNumOperands() - 1; i >= 2; i-=2) - if (!preds.count(phi->getOperand(i).getMBB())) { - phi->RemoveOperand(i); - phi->RemoveOperand(i-1); - } - + ++phi; } } F.RenumberBlocks(); - return DeadBlocks.size(); + return (DeadBlocks.size() || ModifiedPHI); } -