X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FIfConversion.cpp;h=31e36f0168cb910dd1b967790c0521726f602d41;hb=d36696c4e0ccd10a91bad2e3383c50347e2ea5ec;hp=5bfd5499b4397ddbaea806f526f7d00a17598804;hpb=396618b43a85e12d290a90b181c6af5d7c0c5f11;p=oota-llvm.git

diff --git a/lib/CodeGen/IfConversion.cpp b/lib/CodeGen/IfConversion.cpp
index 5bfd5499b43..31e36f0168c 100644
--- a/lib/CodeGen/IfConversion.cpp
+++ b/lib/CodeGen/IfConversion.cpp
@@ -13,11 +13,11 @@
 
 #define DEBUG_TYPE "ifcvt"
 #include "BranchFolding.h"
-#include "llvm/Function.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/MC/MCInstrItineraries.h"
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Target/TargetLowering.h"
@@ -155,7 +155,9 @@ namespace {
     const TargetRegisterInfo *TRI;
     const InstrItineraryData *InstrItins;
     const MachineBranchProbabilityInfo *MBPI;
+    MachineRegisterInfo *MRI;
 
+    bool PreRegAlloc;
     bool MadeChange;
     int FnNum;
   public:
@@ -263,17 +265,23 @@ 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 +629,7 @@ 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 +794,8 @@ 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);
@@ -988,14 +996,13 @@ static void UpdatePredRedefs(MachineInstr *MI, SmallSet<unsigned,4> &Redefs,
   }
   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*/,
                                               false/*IsDead*/,true/*IsUndef*/));
     } else {
-      Redefs.insert(Reg);
       for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs)
         Redefs.insert(*SubRegs);
     }