X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FIfConversion.cpp;h=c61fd17e7911e26a92f27559d1a5af08cb2e6dee;hb=f91387847421a1f0914e757cca96a4d213d32890;hp=3cb3f74bb133aa5008555ca0f719b2b39c540736;hpb=df1ed678904e65192ecdee9bd695f803c550ed68;p=oota-llvm.git

diff --git a/lib/CodeGen/IfConversion.cpp b/lib/CodeGen/IfConversion.cpp
index 3cb3f74bb13..c61fd17e791 100644
--- a/lib/CodeGen/IfConversion.cpp
+++ b/lib/CodeGen/IfConversion.cpp
@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #define DEBUG_TYPE "ifcvt"
+#include "BranchFolding.h"
 #include "llvm/Function.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
@@ -21,6 +22,8 @@
 #include "llvm/Target/TargetMachine.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/DepthFirstIterator.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/STLExtras.h"
@@ -56,7 +59,7 @@ STATISTIC(NumIfConvBBs,    "Number of if-converted blocks");
 STATISTIC(NumDupBBs,       "Number of duplicated blocks");
 
 namespace {
-  class VISIBILITY_HIDDEN IfConverter : public MachineFunctionPass {
+  class IfConverter : public MachineFunctionPass {
     enum IfcvtKind {
       ICNotClassfied,  // BB data valid, but not classified.
       ICSimpleFalse,   // Same as ICSimple, but on the false path.
@@ -144,9 +147,10 @@ namespace {
     const TargetLowering *TLI;
     const TargetInstrInfo *TII;
     bool MadeChange;
+    int FnNum;
   public:
     static char ID;
-    IfConverter() : MachineFunctionPass(&ID) {}
+    IfConverter() : MachineFunctionPass(&ID), FnNum(-1) {}
 
     virtual bool runOnMachineFunction(MachineFunction &MF);
     virtual const char *getPassName() const { return "If Converter"; }
@@ -225,15 +229,14 @@ bool IfConverter::runOnMachineFunction(MachineFunction &MF) {
   TII = MF.getTarget().getInstrInfo();
   if (!TII) return false;
 
-  static int FnNum = -1;
-  DOUT << "\nIfcvt: function (" << ++FnNum <<  ") \'"
-       << MF.getFunction()->getName() << "\'";
+  DEBUG(dbgs() << "\nIfcvt: function (" << ++FnNum <<  ") \'"
+               << MF.getFunction()->getName() << "\'");
 
   if (FnNum < IfCvtFnStart || (IfCvtFnStop != -1 && FnNum > IfCvtFnStop)) {
-    DOUT << " skipped\n";
+    DEBUG(dbgs() << " skipped\n");
     return false;
   }
-  DOUT << "\n";
+  DEBUG(dbgs() << "\n");
 
   MF.RenumberBlocks();
   BBAnalysis.resize(MF.getNumBlockIDs());
@@ -278,13 +281,13 @@ bool IfConverter::runOnMachineFunction(MachineFunction &MF) {
       case ICSimpleFalse: {
         bool isFalse = Kind == ICSimpleFalse;
         if ((isFalse && DisableSimpleF) || (!isFalse && DisableSimple)) break;
-        DOUT << "Ifcvt (Simple" << (Kind == ICSimpleFalse ? " false" :"")
-             << "): BB#" << BBI.BB->getNumber() << " ("
-             << ((Kind == ICSimpleFalse)
-                 ? BBI.FalseBB->getNumber()
-                 : BBI.TrueBB->getNumber()) << ") ";
+        DEBUG(dbgs() << "Ifcvt (Simple" << (Kind == ICSimpleFalse ? " false" :"")
+                     << "): BB#" << BBI.BB->getNumber() << " ("
+                     << ((Kind == ICSimpleFalse)
+                         ? BBI.FalseBB->getNumber()
+                         : BBI.TrueBB->getNumber()) << ") ");
         RetVal = IfConvertSimple(BBI, Kind);
-        DOUT << (RetVal ? "succeeded!" : "failed!") << "\n";
+        DEBUG(dbgs() << (RetVal ? "succeeded!" : "failed!") << "\n");
         if (RetVal) {
           if (isFalse) NumSimpleFalse++;
           else         NumSimple++;
@@ -301,16 +304,16 @@ bool IfConverter::runOnMachineFunction(MachineFunction &MF) {
         if (DisableTriangleR && !isFalse && isRev) break;
         if (DisableTriangleF && isFalse && !isRev) break;
         if (DisableTriangleFR && isFalse && isRev) break;
-        DOUT << "Ifcvt (Triangle";
+        DEBUG(dbgs() << "Ifcvt (Triangle");
         if (isFalse)
-          DOUT << " false";
+          DEBUG(dbgs() << " false");
         if (isRev)
-          DOUT << " rev";
-        DOUT << "): BB#" << BBI.BB->getNumber() << " (T:"
-             << BBI.TrueBB->getNumber() << ",F:"
-             << BBI.FalseBB->getNumber() << ") ";
+          DEBUG(dbgs() << " rev");
+        DEBUG(dbgs() << "): BB#" << BBI.BB->getNumber() << " (T:"
+                     << BBI.TrueBB->getNumber() << ",F:"
+                     << BBI.FalseBB->getNumber() << ") ");
         RetVal = IfConvertTriangle(BBI, Kind);
-        DOUT << (RetVal ? "succeeded!" : "failed!") << "\n";
+        DEBUG(dbgs() << (RetVal ? "succeeded!" : "failed!") << "\n");
         if (RetVal) {
           if (isFalse) {
             if (isRev) NumTriangleFRev++;
@@ -324,11 +327,11 @@ bool IfConverter::runOnMachineFunction(MachineFunction &MF) {
       }
       case ICDiamond: {
         if (DisableDiamond) break;
-        DOUT << "Ifcvt (Diamond): BB#" << BBI.BB->getNumber() << " (T:"
-             << BBI.TrueBB->getNumber() << ",F:"
-             << BBI.FalseBB->getNumber() << ") ";
+        DEBUG(dbgs() << "Ifcvt (Diamond): BB#" << BBI.BB->getNumber() << " (T:"
+                     << BBI.TrueBB->getNumber() << ",F:"
+                     << BBI.FalseBB->getNumber() << ") ");
         RetVal = IfConvertDiamond(BBI, Kind, NumDups, NumDups2);
-        DOUT << (RetVal ? "succeeded!" : "failed!") << "\n";
+        DEBUG(dbgs() << (RetVal ? "succeeded!" : "failed!") << "\n");
         if (RetVal) NumDiamonds++;
         break;
       }
@@ -358,6 +361,13 @@ bool IfConverter::runOnMachineFunction(MachineFunction &MF) {
   Roots.clear();
   BBAnalysis.clear();
 
+  if (MadeChange) {
+    BranchFolder BF(false);
+    BF.OptimizeFunction(MF, TII,
+                        MF.getTarget().getRegisterInfo(),
+                        getAnalysisIfAvailable<MachineModuleInfo>());
+  }
+
   return MadeChange;
 }
 
@@ -547,7 +557,11 @@ void IfConverter::ScanInstructions(BBInfo &BBI) {
     // fallthrough.
     if (!BBI.FalseBB)
       BBI.FalseBB = findFalseBlock(BBI.BB, BBI.TrueBB);  
-    assert(BBI.FalseBB && "Expected to find the fallthrough block!");
+    if (!BBI.FalseBB) {
+      // Malformed bcc? True and false blocks are the same?
+      BBI.IsUnpredicable = true;
+      return;
+    }
   }
 
   // Then scan all the instructions.
@@ -594,7 +608,7 @@ void IfConverter::ScanInstructions(BBInfo &BBI) {
     if (TII->DefinesPredicate(I, PredDefs))
       BBI.ClobbersPred = true;
 
-    if (!TID.isPredicable()) {
+    if (!TII->isPredicable(I)) {
       BBI.IsUnpredicable = true;
       return;
     }
@@ -663,6 +677,13 @@ IfConverter::BBInfo &IfConverter::AnalyzeBlock(MachineBasicBlock *BB,
     return BBI;
   }
 
+  // Do not ifcvt if true and false fallthrough blocks are the same.
+  if (!BBI.FalseBB) {
+    BBI.IsBeingAnalyzed = false;
+    BBI.IsAnalyzed = true;
+    return BBI;
+  }
+
   BBInfo &TrueBBI  = AnalyzeBlock(BBI.TrueBB, Tokens);
   BBInfo &FalseBBI = AnalyzeBlock(BBI.FalseBB, Tokens);
 
@@ -1119,8 +1140,10 @@ void IfConverter::PredicateBlock(BBInfo &BBI,
     if (TII->isPredicated(I))
       continue;
     if (!TII->PredicateInstruction(I, Cond)) {
-      cerr << "Unable to predicate " << *I << "!\n";
-      abort();
+#ifndef NDEBUG
+      dbgs() << "Unable to predicate " << *I << "!\n";
+#endif
+      llvm_unreachable(0);
     }
   }
 
@@ -1153,8 +1176,10 @@ void IfConverter::CopyAndPredicateBlock(BBInfo &ToBBI, BBInfo &FromBBI,
 
     if (!isPredicated)
       if (!TII->PredicateInstruction(MI, Cond)) {
-        cerr << "Unable to predicate " << *MI << "!\n";
-        abort();
+#ifndef NDEBUG
+        dbgs() << "Unable to predicate " << *I << "!\n";
+#endif
+        llvm_unreachable(0);
       }
   }
 
@@ -1187,10 +1212,15 @@ void IfConverter::MergeBlocks(BBInfo &ToBBI, BBInfo &FromBBI) {
   ToBBI.BB->splice(ToBBI.BB->end(),
                    FromBBI.BB, FromBBI.BB->begin(), FromBBI.BB->end());
 
-  // This only works when FromBBI has no predecessors except ToBBI.
-  assert(FromBBI.BB->pred_size() == 1 &&
-         *FromBBI.BB->pred_begin() == ToBBI.BB &&
-         "if-converter not merging block into its unique predecessor");
+  // Redirect all branches to FromBB to ToBB.
+  std::vector<MachineBasicBlock *> Preds(FromBBI.BB->pred_begin(),
+                                         FromBBI.BB->pred_end());
+  for (unsigned i = 0, e = Preds.size(); i != e; ++i) {
+    MachineBasicBlock *Pred = Preds[i];
+    if (Pred == ToBBI.BB)
+      continue;
+    Pred->ReplaceUsesOfBlockWith(FromBBI.BB, ToBBI.BB);
+  }
  
   std::vector<MachineBasicBlock *> Succs(FromBBI.BB->succ_begin(),
                                          FromBBI.BB->succ_end());