Fixing typo in comment.

[oota-llvm.git] / lib / CodeGen / IfConversion.cpp

diff --git a/lib/CodeGen/IfConversion.cpp b/lib/CodeGen/IfConversion.cpp
index 75ae5b9c2c2760b9c5834c58d491050945072f53..eaff93fd7fc53633c497ba344d1a298cda063629 100644 (file)
--- a/lib/CodeGen/IfConversion.cpp
+++ b/lib/CodeGen/IfConversion.cpp
@@ -12,24 +12,25 @@
 //===----------------------------------------------------------------------===//
 
 #define DEBUG_TYPE "ifcvt"
-#include "BranchFolding.h"
-#include "llvm/Function.h"
 #include "llvm/CodeGen/Passes.h"
-#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "BranchFolding.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallSet.h"
+#include "llvm/ADT/Statistic.h"
 #include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/MC/MCInstrItineraries.h"
-#include "llvm/Target/TargetInstrInfo.h"
-#include "llvm/Target/TargetLowering.h"
-#include "llvm/Target/TargetMachine.h"
-#include "llvm/Target/TargetRegisterInfo.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
-#include "llvm/ADT/SmallSet.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/STLExtras.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetLowering.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetRegisterInfo.h"
 using namespace llvm;
 
 // Hidden options for help debugging.
@@ -150,12 +151,14 @@ namespace {
     /// basic block number.
     std::vector<BBInfo> BBAnalysis;
 
-    const TargetLowering *TLI;
+    const TargetLoweringBase *TLI;
     const TargetInstrInfo *TII;
     const TargetRegisterInfo *TRI;
     const InstrItineraryData *InstrItins;
     const MachineBranchProbabilityInfo *MBPI;
+    MachineRegisterInfo *MRI;
 
+    bool PreRegAlloc;
     bool MadeChange;
     int FnNum;
   public:
@@ -263,17 +266,23 @@ bool IfConverter::runOnMachineFunction(MachineFunction &MF) {
   TII = MF.getTarget().getInstrInfo();
   TRI = MF.getTarget().getRegisterInfo();
   MBPI = &getAnalysis<MachineBranchProbabilityInfo>();
+  MRI = &MF.getRegInfo();
   InstrItins = MF.getTarget().getInstrItineraryData();
   if (!TII) return false;
 
-  // Tail merge tend to expose more if-conversion opportunities.
-  BranchFolder BF(true, false);
-  bool BFChange = BF.OptimizeFunction(MF, TII,
+  PreRegAlloc = MRI->isSSA();
+
+  bool BFChange = false;
+  if (!PreRegAlloc) {
+    // Tail merge tend to expose more if-conversion opportunities.
+    BranchFolder BF(true, false);
+    BFChange = BF.OptimizeFunction(MF, TII,
                                    MF.getTarget().getRegisterInfo(),
                                    getAnalysisIfAvailable<MachineModuleInfo>());
+  }
 
   DEBUG(dbgs() << "\nIfcvt: function (" << ++FnNum <<  ") \'"
-               << MF.getFunction()->getName() << "\'");
+               << MF.getName() << "\'");
 
   if (FnNum < IfCvtFnStart || (IfCvtFnStop != -1 && FnNum > IfCvtFnStop)) {
     DEBUG(dbgs() << " skipped\n");
@@ -621,7 +630,7 @@ void IfConverter::ScanInstructions(BBInfo &BBI) {
   if (BBI.IsDone)
     return;
 
-  bool AlreadyPredicated = BBI.Predicate.size() > 0;
+  bool AlreadyPredicated = !BBI.Predicate.empty();
   // First analyze the end of BB branches.
   BBI.TrueBB = BBI.FalseBB = NULL;
   BBI.BrCond.clear();
@@ -786,8 +795,8 @@ IfConverter::BBInfo &IfConverter::AnalyzeBlock(MachineBasicBlock *BB,
 
   unsigned Dups = 0;
   unsigned Dups2 = 0;
-  bool TNeedSub = TrueBBI.Predicate.size() > 0;
-  bool FNeedSub = FalseBBI.Predicate.size() > 0;
+  bool TNeedSub = !TrueBBI.Predicate.empty();
+  bool FNeedSub = !FalseBBI.Predicate.empty();
   bool Enqueued = false;
 
   BranchProbability Prediction = MBPI->getEdgeProbability(BB, TrueBBI.BB);
@@ -962,9 +971,8 @@ static void InitPredRedefs(MachineBasicBlock *BB, SmallSet<unsigned,4> &Redefs,
          E = BB->livein_end(); I != E; ++I) {
     unsigned Reg = *I;
     Redefs.insert(Reg);
-    for (const uint16_t *Subreg = TRI->getSubRegisters(Reg);
-         *Subreg; ++Subreg)
-      Redefs.insert(*Subreg);
+    for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs)
+      Redefs.insert(*SubRegs);
   }
 }
 
@@ -983,21 +991,20 @@ static void UpdatePredRedefs(MachineInstr *MI, SmallSet<unsigned,4> &Redefs,
       Defs.push_back(Reg);
     else if (MO.isKill()) {
       Redefs.erase(Reg);
-      for (const uint16_t *SR = TRI->getSubRegisters(Reg); *SR; ++SR)
-        Redefs.erase(*SR);
+      for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs)
+        Redefs.erase(*SubRegs);
     }
   }
+  MachineInstrBuilder MIB(*MI->getParent()->getParent(), MI);
   for (unsigned i = 0, e = Defs.size(); i != e; ++i) {
     unsigned Reg = Defs[i];
-    if (Redefs.count(Reg)) {
+    if (!Redefs.insert(Reg)) {
       if (AddImpUse)
         // Treat predicated update as read + write.
-        MI->addOperand(MachineOperand::CreateReg(Reg, false/*IsDef*/,
-                                                true/*IsImp*/,false/*IsKill*/));
+        MIB.addReg(Reg, RegState::Implicit | RegState::Undef);
     } else {
-      Redefs.insert(Reg);
-      for (const uint16_t *SR = TRI->getSubRegisters(Reg); *SR; ++SR)
-        Redefs.insert(*SR);
+      for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs)
+        Redefs.insert(*SubRegs);
     }
   }
 }
@@ -1047,6 +1054,10 @@ bool IfConverter::IfConvertSimple(BBInfo &BBI, IfcvtKind Kind) {
     // Copy instructions in the true block, predicate them, and add them to
     // the entry block.
     CopyAndPredicateBlock(BBI, *CvtBBI, Cond, Redefs);
+
+    // RemoveExtraEdges won't work if the block has an unanalyzable branch, so
+    // explicitly remove CvtBBI as a successor.
+    BBI.BB->removeSuccessor(CvtBBI->BB);
   } else {
     PredicateBlock(*CvtBBI, CvtBBI->BB->end(), Cond, Redefs);
 
@@ -1139,6 +1150,10 @@ bool IfConverter::IfConvertTriangle(BBInfo &BBI, IfcvtKind Kind) {
     // Copy instructions in the true block, predicate them, and add them to
     // the entry block.
     CopyAndPredicateBlock(BBI, *CvtBBI, Cond, Redefs, true);
+
+    // RemoveExtraEdges won't work if the block has an unanalyzable branch, so
+    // explicitly remove CvtBBI as a successor.
+    BBI.BB->removeSuccessor(CvtBBI->BB);
   } else {
     // Predicate the 'true' block after removing its branch.
     CvtBBI->NonPredSize -= TII->RemoveBranch(*CvtBBI->BB);
@@ -1335,8 +1350,8 @@ bool IfConverter::IfConvertDiamond(BBInfo &BBI, IfcvtKind Kind,
           // These are defined before ctrl flow reach the 'false' instructions.
           // They cannot be modified by the 'true' instructions.
           ExtUses.insert(Reg);
-          for (const uint16_t *SR = TRI->getSubRegisters(Reg); *SR; ++SR)
-            ExtUses.insert(*SR);
+          for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs)
+            ExtUses.insert(*SubRegs);
         }
       }
 
@@ -1344,8 +1359,8 @@ bool IfConverter::IfConvertDiamond(BBInfo &BBI, IfcvtKind Kind,
         unsigned Reg = Defs[i];
         if (!ExtUses.count(Reg)) {
           RedefsByFalse.insert(Reg);
-          for (const uint16_t *SR = TRI->getSubRegisters(Reg); *SR; ++SR)
-            RedefsByFalse.insert(*SR);
+          for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs)
+            RedefsByFalse.insert(*SubRegs);
         }
       }
     }
@@ -1550,7 +1565,7 @@ void IfConverter::MergeBlocks(BBInfo &ToBBI, BBInfo &FromBBI, bool AddEdges) {
     if (Succ == FallThrough)
       continue;
     FromBBI.BB->removeSuccessor(Succ);
-    if (AddEdges)
+    if (AddEdges && !ToBBI.BB->isSuccessor(Succ))
       ToBBI.BB->addSuccessor(Succ);
   }