Remove the successor probabilities normalization in tail duplication pass.

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

diff --git a/lib/CodeGen/TailDuplication.cpp b/lib/CodeGen/TailDuplication.cpp
index ca929d9fa4504f5b80f8ec872c40147839de5994..1f5b54866ac627179045d51751a2e3417e3ddcc5 100644 (file)
--- a/lib/CodeGen/TailDuplication.cpp
+++ b/lib/CodeGen/TailDuplication.cpp
@@ -161,7 +161,7 @@ void TailDuplicatePass::getAnalysisUsage(AnalysisUsage &AU) const {
 
 static void VerifyPHIs(MachineFunction &MF, bool CheckExtra) {
   for (MachineFunction::iterator I = ++MF.begin(), E = MF.end(); I != E; ++I) {
-    MachineBasicBlock *MBB = I;
+    MachineBasicBlock *MBB = &*I;
     SmallSetVector<MachineBasicBlock*, 8> Preds(MBB->pred_begin(),
                                                 MBB->pred_end());
     MachineBasicBlock::iterator MI = MBB->begin();
@@ -322,7 +322,7 @@ bool TailDuplicatePass::TailDuplicateBlocks(MachineFunction &MF) {
   }
 
   for (MachineFunction::iterator I = ++MF.begin(), E = MF.end(); I != E; ) {
-    MachineBasicBlock *MBB = I++;
+    MachineBasicBlock *MBB = &*I++;
 
     if (NumTails == TailDupLimit)
       break;
@@ -607,6 +607,27 @@ TailDuplicatePass::shouldTailDuplicate(const MachineFunction &MF,
       return false;
   }
 
+  // Check if any of the successors of TailBB has a PHI node in which the
+  // value corresponding to TailBB uses a subregister.
+  // If a phi node uses a register paired with a subregister, the actual
+  // "value type" of the phi may differ from the type of the register without
+  // any subregisters. Due to a bug, tail duplication may add a new operand
+  // without a necessary subregister, producing an invalid code. This is
+  // demonstrated by test/CodeGen/Hexagon/tail-dup-subreg-abort.ll.
+  // Disable tail duplication for this case for now, until the problem is
+  // fixed.
+  for (auto SB : TailBB.successors()) {
+    for (auto &I : *SB) {
+      if (!I.isPHI())
+        break;
+      unsigned Idx = getPHISrcRegOpIdx(&I, &TailBB);
+      assert(Idx != 0);
+      MachineOperand &PU = I.getOperand(Idx);
+      if (PU.getSubReg() != 0)
+        return false;
+    }
+  }
+
   if (HasIndirectbr && PreRegAlloc)
     return true;
 
@@ -673,7 +694,7 @@ TailDuplicatePass::duplicateSimpleBB(MachineBasicBlock *TailBB,
        PE = Preds.end(); PI != PE; ++PI) {
     MachineBasicBlock *PredBB = *PI;
 
-    if (PredBB->getLandingPadSuccessor())
+    if (PredBB->hasEHPadSuccessor())
       continue;
 
     if (bothUsedInPHI(*PredBB, Succs))
@@ -689,7 +710,7 @@ TailDuplicatePass::duplicateSimpleBB(MachineBasicBlock *TailBB,
                  << "From simple Succ: " << *TailBB);
 
     MachineBasicBlock *NewTarget = *TailBB->succ_begin();
-    MachineBasicBlock *NextBB = std::next(MachineFunction::iterator(PredBB));
+    MachineBasicBlock *NextBB = &*std::next(PredBB->getIterator());
 
     // Make PredFBB explicit.
     if (PredCond.empty())
@@ -724,12 +745,12 @@ TailDuplicatePass::duplicateSimpleBB(MachineBasicBlock *TailBB,
     if (PredTBB)
       TII->InsertBranch(*PredBB, PredTBB, PredFBB, PredCond, DebugLoc());
 
-    uint32_t Weight = MBPI->getEdgeWeight(PredBB, TailBB);
+    auto Prob = MBPI->getEdgeProbability(PredBB, TailBB);
     PredBB->removeSuccessor(TailBB);
     unsigned NumSuccessors = PredBB->succ_size();
     assert(NumSuccessors <= 1);
     if (NumSuccessors == 0 || *PredBB->succ_begin() != NewTarget)
-      PredBB->addSuccessor(NewTarget, Weight);
+      PredBB->addSuccessor(NewTarget, Prob);
 
     TDBBs.push_back(PredBB);
   }
@@ -791,8 +812,8 @@ TailDuplicatePass::TailDuplicate(MachineBasicBlock *TailBB,
       RS->enterBasicBlock(PredBB);
       if (!PredBB->empty())
         RS->forward(std::prev(PredBB->end()));
-      for (unsigned LI : TailBB->liveins()) {
-        if (!RS->isRegUsed(LI, false))
+      for (const auto &LI : TailBB->liveins()) {
+        if (!RS->isRegUsed(LI.PhysReg, false))
           // If a register is previously livein to the tail but it's not live
           // at the end of predecessor BB, then it should be added to its
           // livein list.
@@ -837,7 +858,7 @@ TailDuplicatePass::TailDuplicate(MachineBasicBlock *TailBB,
            "TailDuplicate called on block with multiple successors!");
     for (MachineBasicBlock::succ_iterator I = TailBB->succ_begin(),
            E = TailBB->succ_end(); I != E; ++I)
-      PredBB->addSuccessor(*I, MBPI->getEdgeWeight(TailBB, I));
+      PredBB->addSuccessor(*I, MBPI->getEdgeProbability(TailBB, I));
 
     Changed = true;
     ++NumTailDups;
@@ -846,7 +867,7 @@ TailDuplicatePass::TailDuplicate(MachineBasicBlock *TailBB,
   // If TailBB was duplicated into all its predecessors except for the prior
   // block, which falls through unconditionally, move the contents of this
   // block into the prior block.
-  MachineBasicBlock *PrevBB = std::prev(MachineFunction::iterator(TailBB));
+  MachineBasicBlock *PrevBB = &*std::prev(TailBB->getIterator());
   MachineBasicBlock *PriorTBB = nullptr, *PriorFBB = nullptr;
   SmallVector<MachineOperand, 4> PriorCond;
   // This has to check PrevBB->succ_size() because EH edges are ignored by