Oy! When reverting r68073, I added in experimental code. Sorry...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@68099 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/CodeGen/MachineBasicBlock.h b/include/llvm/CodeGen/MachineBasicBlock.h
index 1ba7e798f832d602f5686a2f8b08ce6322fa3198..f962273d2beedfcededcfb8d49774495451fe266 100644 (file)
--- a/include/llvm/CodeGen/MachineBasicBlock.h
+++ b/include/llvm/CodeGen/MachineBasicBlock.h
@@ -253,6 +253,15 @@ public:
   /// it returns end()
   iterator getFirstTerminator();
 
+  /// isOnlyReachableViaFallthough - Return true if this basic block has
+  /// exactly one predecessor and the control transfer mechanism between
+  /// the predecessor and this block is a fall-through.
+  bool isOnlyReachableByFallthrough() const {
+    return !pred_empty() &&
+           next(pred_begin()) == pred_end() &&
+           (*pred_begin())->getFirstTerminator() == (*pred_begin())->end();
+  }
+
   void pop_front() { Insts.pop_front(); }
   void pop_back() { Insts.pop_back(); }
   void push_back(MachineInstr *MI) { Insts.push_back(MI); }

diff --git a/lib/CodeGen/Spiller.cpp b/lib/CodeGen/Spiller.cpp
index 4bfae39c42d0586d753f9d6758f105f4139749a7..7b2a32f1c762e2c5784c3cf1d708278790dce36c 100644 (file)
--- a/lib/CodeGen/Spiller.cpp
+++ b/lib/CodeGen/Spiller.cpp
@@ -578,20 +578,6 @@ bool LocalSpiller::runOnMachineFunction(MachineFunction &MF, VirtRegMap &VRM) {
   DOUT << "**** Post Machine Instrs ****\n";
   DEBUG(MF.dump());
 
-  // See if any of the spills we added are actually dead and can be deleted.
-  for (std::vector<MachineInstr*> >::iterator
-         I = AddedSpills.begin(), E = AddedSpills.end(); I != E; ++I) {
-    MachineInstr *MI = *I;
-
-    if (VRM.OnlyUseOfStackSlot(MI)) {
-      MachineBasicBlock *MBB = MI->getParent();
-      DOUT << "Removed dead store:\t" << *MI;
-      VRM.RemoveMachineInstrFromMaps(MI);
-      MBB->erase(MI);
-      ++NumDSE;
-    }
-  }
-
   // Mark unused spill slots.
   MachineFrameInfo *MFI = MF.getFrameInfo();
   int SS = VRM.getLowSpillSlot();
@@ -602,7 +588,6 @@ bool LocalSpiller::runOnMachineFunction(MachineFunction &MF, VirtRegMap &VRM) {
         ++NumDSS;
       }
 
-  AddedSpills.clear();
   return true;
 }
 
@@ -813,50 +798,9 @@ bool LocalSpiller::CommuteToFoldReload(MachineBasicBlock &MBB,
   return false;
 }
 
-void LocalSpiller::RemoveDeadStore(MachineInstr *Store,
-                                   MachineBasicBlock &MBB,
-                                   MachineBasicBlock::iterator &MII,
-                                   SmallSet<MachineInstr*, 4> &ReMatDefs,
-                                   BitVector &RegKills,
-                                   std::vector<MachineOperand*> &KillOps,
-                                   VirtRegMap &VRM) {
-  // If there is a dead store to this stack slot, nuke it now.
-  DOUT << "Removed dead store:\t" << *Store;
-  ++NumDSE;
-  SmallVector<unsigned, 2> KillRegs;
-  InvalidateKills(*Store, RegKills, KillOps, &KillRegs);
-
-  MachineBasicBlock::iterator PrevMII = Store;
-  bool CheckDef = PrevMII != MBB.begin();
-  if (CheckDef) --PrevMII;
-
-  VRM.RemoveMachineInstrFromMaps(Store);
-  MBB.erase(Store);
-
-  if (CheckDef) {
-    // Look at defs of killed registers on the store. Mark the defs as dead
-    // since the store has been deleted and they aren't being reused.
-    for (unsigned j = 0, ee = KillRegs.size(); j != ee; ++j) {
-      bool HasOtherDef = false;
-
-      if (InvalidateRegDef(PrevMII, *MII, KillRegs[j], HasOtherDef)) {
-        MachineInstr *DeadDef = PrevMII;
-
-        if (ReMatDefs.count(DeadDef) && !HasOtherDef) {
-          // FIXME: This assumes a remat def does not have side effects.
-          VRM.RemoveMachineInstrFromMaps(DeadDef);
-          MBB.erase(DeadDef);
-          ++NumDRM;
-        }
-      }
-    }
-  }
-}
-
 /// SpillRegToStackSlot - Spill a register to a specified stack slot. Check if
 /// the last store to the same slot is now dead. If so, remove the last store.
-void
-LocalSpiller::SpillRegToStackSlot(MachineBasicBlock &MBB,
+void LocalSpiller::SpillRegToStackSlot(MachineBasicBlock &MBB,
                                   MachineBasicBlock::iterator &MII,
                                   int Idx, unsigned PhysReg, int StackSlot,
                                   const TargetRegisterClass *RC,
@@ -872,8 +816,36 @@ LocalSpiller::SpillRegToStackSlot(MachineBasicBlock &MBB,
   DOUT << "Store:\t" << *StoreMI;
 
   // If there is a dead store to this stack slot, nuke it now.
-  if (LastStore)
-    RemoveDeadStore(LastStore, MBB, MII, ReMatDefs, RegKills, KillOps, VRM);
+  if (LastStore) {
+    DOUT << "Removed dead store:\t" << *LastStore;
+    ++NumDSE;
+    SmallVector<unsigned, 2> KillRegs;
+    InvalidateKills(*LastStore, RegKills, KillOps, &KillRegs);
+    MachineBasicBlock::iterator PrevMII = LastStore;
+    bool CheckDef = PrevMII != MBB.begin();
+    if (CheckDef)
+      --PrevMII;
+    VRM.RemoveMachineInstrFromMaps(LastStore);
+    MBB.erase(LastStore);
+    if (CheckDef) {
+      // Look at defs of killed registers on the store. Mark the defs
+      // as dead since the store has been deleted and they aren't
+      // being reused.
+      for (unsigned j = 0, ee = KillRegs.size(); j != ee; ++j) {
+        bool HasOtherDef = false;
+        if (InvalidateRegDef(PrevMII, *MII, KillRegs[j], HasOtherDef)) {
+          MachineInstr *DeadDef = PrevMII;
+          if (ReMatDefs.count(DeadDef) && !HasOtherDef) {
+            // FIXME: This assumes a remat def does not have side
+            // effects.
+            VRM.RemoveMachineInstrFromMaps(DeadDef);
+            MBB.erase(DeadDef);
+            ++NumDRM;
+          }
+        }
+      }
+    }
+  }
 
   LastStore = next(MII);
 
@@ -1088,7 +1060,6 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM,
     if (VRM.isSpillPt(&MI)) {
       std::vector<std::pair<unsigned,bool> > &SpillRegs =
         VRM.getSpillPtSpills(&MI);
-
       for (unsigned i = 0, e = SpillRegs.size(); i != e; ++i) {
         unsigned VirtReg = SpillRegs[i].first;
         bool isKill = SpillRegs[i].second;
@@ -1102,9 +1073,7 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM,
         VRM.addSpillSlotUse(StackSlot, StoreMI);
         DOUT << "Store:\t" << *StoreMI;
         VRM.virtFolded(VirtReg, StoreMI, VirtRegMap::isMod);
-        AddedSpills.push_back(StoreMI);
       }
-
       NextMII = next(MII);
     }
 

diff --git a/lib/CodeGen/Spiller.h b/lib/CodeGen/Spiller.h
index 0ac6fa0db6cc9ec8ef636dee550a5660a3533e5a..5a42a8279db84b5d885def552974c9d1d6349346 100644 (file)
--- a/lib/CodeGen/Spiller.h
+++ b/lib/CodeGen/Spiller.h
@@ -285,7 +285,6 @@ namespace llvm {
     const TargetRegisterInfo *TRI;
     const TargetInstrInfo *TII;
     DenseMap<MachineInstr*, unsigned> DistanceMap;
-    std::vector<MachineInstr*> AddedSpills;
   public:
     bool runOnMachineFunction(MachineFunction &MF, VirtRegMap &VRM);
   private:
@@ -306,14 +305,6 @@ namespace llvm {
                              std::vector<MachineOperand*> &KillOps,
                              const TargetRegisterInfo *TRI,
                              VirtRegMap &VRM);
-    void RemoveDeadStore(MachineInstr *Store,
-                         MachineBasicBlock &MBB,
-                         MachineBasicBlock::iterator &MII,
-                         SmallSet<MachineInstr*, 4> &ReMatDefs,
-                         BitVector &RegKills,
-                         std::vector<MachineOperand*> &KillOps,
-                         VirtRegMap &VRM);
-
     void SpillRegToStackSlot(MachineBasicBlock &MBB,
                              MachineBasicBlock::iterator &MII,
                              int Idx, unsigned PhysReg, int StackSlot,

diff --git a/lib/CodeGen/VirtRegMap.cpp b/lib/CodeGen/VirtRegMap.cpp
index c5bfcfd301234dd04e004bce19429c0c4b46b725..cb0f764343e2bb74d55b8bc240d451b0ae98d28d 100644 (file)
--- a/lib/CodeGen/VirtRegMap.cpp
+++ b/lib/CodeGen/VirtRegMap.cpp
@@ -188,7 +188,7 @@ void VirtRegMap::RemoveMachineInstrFromMaps(MachineInstr *MI) {
     if (MF->getFrameInfo()->isFixedObjectIndex(FI))
       continue;
     // This stack reference was produced by instruction selection and
-    // is not a spill.
+    // is not a spill
     if (FI < LowSpillSlot)
       continue;
     assert((unsigned)FI-LowSpillSlot < SpillSlotToUsesMap.size()
@@ -201,27 +201,6 @@ void VirtRegMap::RemoveMachineInstrFromMaps(MachineInstr *MI) {
   EmergencySpillMap.erase(MI);
 }
 
-bool VirtRegMap::OnlyUseOfStackSlot(const MachineInstr *MI) const {
-  for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
-    const MachineOperand &MO = MI->getOperand(i);
-    if (!MO.isFI())
-      continue;
-    int FI = MO.getIndex();
-    if (MF->getFrameInfo()->isFixedObjectIndex(FI))
-      continue;
-    // This stack reference was produced by instruction selection and
-    // is not a spill.
-    if (FI < LowSpillSlot)
-      continue;
-    assert((unsigned)FI-LowSpillSlot < SpillSlotToUsesMap.size()
-           && "Invalid spill slot");
-    if (SpillSlotToUsesMap[FI - LowSpillSlot].size() != 1)
-      return false;
-  }
-
-  return true;
-}
-
 void VirtRegMap::print(std::ostream &OS, const Module* M) const {
   const TargetRegisterInfo* TRI = MF->getTarget().getRegisterInfo();
 

diff --git a/lib/CodeGen/VirtRegMap.h b/lib/CodeGen/VirtRegMap.h
index 962c9dea3e9413562b6b59dbf22e3f0e81c43d70..2e9c899baabb45d20f06a6237e876ecc59113eb5 100644 (file)
--- a/lib/CodeGen/VirtRegMap.h
+++ b/lib/CodeGen/VirtRegMap.h
@@ -430,8 +430,6 @@ namespace llvm {
     /// the folded instruction map and spill point map.
     void RemoveMachineInstrFromMaps(MachineInstr *MI);
 
-    bool OnlyUseOfStackSlot(const MachineInstr *MI) const;
-
     void print(std::ostream &OS, const Module* M = 0) const;
     void print(std::ostream *OS) const { if (OS) print(*OS); }
     void dump() const;

diff --git a/lib/Target/X86/AsmPrinter/X86ATTAsmPrinter.cpp b/lib/Target/X86/AsmPrinter/X86ATTAsmPrinter.cpp
index 3bdcf88365f9bde8a67edca807ee6f879e4b3352..d8a33957d5cf998c498e3382da465b70453e4c15 100644 (file)
--- a/lib/Target/X86/AsmPrinter/X86ATTAsmPrinter.cpp
+++ b/lib/Target/X86/AsmPrinter/X86ATTAsmPrinter.cpp
@@ -238,7 +238,12 @@ bool X86ATTAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
   for (MachineFunction::const_iterator I = MF.begin(), E = MF.end();
        I != E; ++I) {
     // Print a label for the basic block.
-    if (!I->pred_empty()) {
+    if (!VerboseAsm && (I->pred_empty() || I->isOnlyReachableByFallthrough())) {
+      // This is an entry block or a block that's only reachable via a
+      // fallthrough edge. In non-VerboseAsm mode, don't print the label.
+      assert((I->pred_empty() || (*I->pred_begin())->isLayoutSuccessor(I)) &&
+             "Fall-through predecessor not adjacent to its successor!");
+    } else {
       printBasicBlockLabel(I, true, true, VerboseAsm);
       O << '\n';
     }