//===----------------------------------------------------------------------===//
#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/Support/CFG.h"
-#include "llvm/Support/Compiler.h"
+#include "llvm/CodeGen/MachineLoopInfo.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/CodeGen/MachineRegisterInfo.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<DominatorTreeWrapperPass>();
+ }
};
}
char UnreachableBlockElim::ID = 0;
-static RegisterPass<UnreachableBlockElim>
-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<BasicBlock*> Reachable;
+ SmallPtrSet<BasicBlock*, 8> Reachable;
// Mark all reachable blocks.
- for (df_ext_iterator<Function*> 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.
}
// 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<UnreachableMachineBlockElim>
-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<MachineLoopInfo>();
+ AU.addPreserved<MachineDominatorTree>();
+ MachineFunctionPass::getAnalysisUsage(AU);
+}
bool UnreachableMachineBlockElim::runOnMachineFunction(MachineFunction &F) {
- std::set<MachineBasicBlock*> Reachable;
+ SmallPtrSet<MachineBasicBlock*, 8> Reachable;
+ bool ModifiedPHI = false;
+
+ MMI = getAnalysisIfAvailable<MachineModuleInfo>();
+ MachineDominatorTree *MDT = getAnalysisIfAvailable<MachineDominatorTree>();
+ MachineLoopInfo *MLI = getAnalysisIfAvailable<MachineLoopInfo>();
// Mark all reachable blocks.
- for (df_ext_iterator<MachineFunction*> 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<MachineBasicBlock*> DeadBlocks;
- for (MachineFunction::iterator I = F.begin(), E = F.end(); I != E; ++I)
- if (!Reachable.count(I)) {
- MachineBasicBlock *BB = I;
+ 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);
}
-
- if (start->getNumOperands() == 1) {
- MachineInstr* phi = start;
- start++;
- phi->eraseFromParent();
- } else
- start++;
+
+ start++;
}
-
+
BB->removeSuccessor(BB->succ_begin());
}
}
+ }
// Actually remove the blocks now.
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;
+ // Prune unneeded PHI entries.
+ SmallPtrSet<MachineBasicBlock*, 8> preds(BB->pred_begin(),
+ BB->pred_end());
+ MachineBasicBlock::iterator phi = BB->begin();
+ 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();
+
+ 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);
+ }
+
+ continue;
+ }
+
+ ++phi;
+ }
+ }
+
F.RenumberBlocks();
- return DeadBlocks.size();
+ return (DeadBlocks.size() || ModifiedPHI);
}
-