X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FUnreachableBlockElim.cpp;h=52693f03e82822e6bb9e87b98ef324b3c717ed78;hb=de4a1274706d7449870dac5bed05d27a6772d4ed;hp=3c3fca51b66f27931e640b39b7f0f87d2572a16a;hpb=d735b8019b0f297d7c14b55adcd887af24d8e602;p=oota-llvm.git

diff --git a/lib/CodeGen/UnreachableBlockElim.cpp b/lib/CodeGen/UnreachableBlockElim.cpp
index 3c3fca51b66..52693f03e82 100644
--- a/lib/CodeGen/UnreachableBlockElim.cpp
+++ b/lib/CodeGen/UnreachableBlockElim.cpp
@@ -26,26 +26,37 @@
 #include "llvm/Function.h"
 #include "llvm/Pass.h"
 #include "llvm/Type.h"
+#include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/ProfileInfo.h"
+#include "llvm/CodeGen/MachineDominators.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/CodeGen/MachineLoopInfo.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/Support/CFG.h"
-#include "llvm/Support/Compiler.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 {
+  class UnreachableBlockElim : public FunctionPass {
     virtual bool runOnFunction(Function &F);
   public:
     static char ID; // Pass identification, replacement for typeid
-    UnreachableBlockElim() : FunctionPass(&ID) {}
+    UnreachableBlockElim() : FunctionPass(ID) {
+      initializeUnreachableBlockElimPass(*PassRegistry::getPassRegistry());
+    }
+
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.addPreserved<DominatorTree>();
+      AU.addPreserved<ProfileInfo>();
+    }
   };
 }
 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();
@@ -76,33 +87,46 @@ bool UnreachableBlockElim::runOnFunction(Function &F) {
     }
 
   // Actually remove the blocks now.
-  for (unsigned i = 0, e = DeadBlocks.size(); i != e; ++i)
+  ProfileInfo *PI = getAnalysisIfAvailable<ProfileInfo>();
+  for (unsigned i = 0, e = DeadBlocks.size(); i != e; ++i) {
+    if (PI) PI->removeBlock(DeadBlocks[i]);
     DeadBlocks[i]->eraseFromParent();
+  }
 
   return DeadBlocks.size();
 }
 
 
 namespace {
-  class VISIBILITY_HIDDEN UnreachableMachineBlockElim : 
-        public MachineFunctionPass {
+  class UnreachableMachineBlockElim : public MachineFunctionPass {
     virtual bool runOnMachineFunction(MachineFunction &F);
-    
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const;
+    MachineModuleInfo *MMI;
   public:
     static char ID; // Pass identification, replacement for typeid
-    UnreachableMachineBlockElim() : MachineFunctionPass(&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) {
   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*, SmallPtrSet<MachineBasicBlock*, 8> >
@@ -115,27 +139,30 @@ bool UnreachableMachineBlockElim::runOnMachineFunction(MachineFunction &F) {
   std::vector<MachineBasicBlock*> 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());
       }
     }
@@ -149,17 +176,17 @@ 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<MachineBasicBlock*, 8> preds(BB->pred_begin(), 
+    SmallPtrSet<MachineBasicBlock*, 8> 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();
@@ -167,19 +194,22 @@ 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;
       }
-  
+
       ++phi;
     }
   }
 
   F.RenumberBlocks();
 
-  return DeadBlocks.size();
+  return (DeadBlocks.size() || ModifiedPHI);
 }
-