X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FPHIElimination.cpp;h=dcd907229528c8be6b3e077147e4dbe1fde851c7;hb=b59d46efa521801a3d42fc5f53fedf3e81b070ce;hp=f046ac9627d92719fd17747d18a6154353cfb955;hpb=8d49134eeaa36953410c2fba65f7237fb3f079e7;p=oota-llvm.git

diff --git a/lib/CodeGen/PHIElimination.cpp b/lib/CodeGen/PHIElimination.cpp
index f046ac9627d..dcd90722952 100644
--- a/lib/CodeGen/PHIElimination.cpp
+++ b/lib/CodeGen/PHIElimination.cpp
@@ -66,7 +66,7 @@ namespace {
     ///
     bool EliminatePHINodes(MachineFunction &MF, MachineBasicBlock &MBB);
     void LowerPHINode(MachineBasicBlock &MBB,
-                      MachineBasicBlock::iterator AfterPHIsIt);
+                      MachineBasicBlock::iterator LastPHIIt);
 
     /// analyzePHINodes - Gather information about the PHI nodes in
     /// here. In particular, we want to map the number of uses of a virtual
@@ -116,6 +116,7 @@ INITIALIZE_PASS_END(PHIElimination, "phi-node-elimination",
 
 void PHIElimination::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.addPreserved<LiveVariables>();
+  AU.addPreserved<SlotIndexes>();
   AU.addPreserved<LiveIntervals>();
   AU.addPreserved<MachineDominatorTree>();
   AU.addPreserved<MachineLoopInfo>();
@@ -171,9 +172,6 @@ bool PHIElimination::runOnMachineFunction(MachineFunction &MF) {
   ImpDefs.clear();
   VRegPHIUseCount.clear();
 
-  if (LIS)
-    MF.verify(this, "After PHI elimination");
-
   return Changed;
 }
 
@@ -187,10 +185,11 @@ bool PHIElimination::EliminatePHINodes(MachineFunction &MF,
 
   // Get an iterator to the first instruction after the last PHI node (this may
   // also be the end of the basic block).
-  MachineBasicBlock::iterator AfterPHIsIt = MBB.SkipPHIsAndLabels(MBB.begin());
+  MachineBasicBlock::iterator LastPHIIt =
+    prior(MBB.SkipPHIsAndLabels(MBB.begin()));
 
   while (MBB.front().isPHI())
-    LowerPHINode(MBB, AfterPHIsIt);
+    LowerPHINode(MBB, LastPHIIt);
 
   return true;
 }
@@ -220,8 +219,11 @@ static bool isSourceDefinedByImplicitDef(const MachineInstr *MPhi,
 /// LowerPHINode - Lower the PHI node at the top of the specified block,
 ///
 void PHIElimination::LowerPHINode(MachineBasicBlock &MBB,
-                                  MachineBasicBlock::iterator AfterPHIsIt) {
+                                  MachineBasicBlock::iterator LastPHIIt) {
   ++NumLowered;
+
+  MachineBasicBlock::iterator AfterPHIsIt = llvm::next(LastPHIIt);
+
   // Unlink the PHI node from the basic block, but don't delete the PHI yet.
   MachineInstr *MPhi = MBB.remove(MBB.begin());
 
@@ -305,38 +307,39 @@ void PHIElimination::LowerPHINode(MachineBasicBlock &MBB,
   // Update LiveIntervals for the new copy or implicit def.
   if (LIS) {
     MachineInstr *NewInstr = prior(AfterPHIsIt);
-    LIS->InsertMachineInstrInMaps(NewInstr);
+    SlotIndex DestCopyIndex = LIS->InsertMachineInstrInMaps(NewInstr);
 
     SlotIndex MBBStartIndex = LIS->getMBBStartIdx(&MBB);
-    SlotIndex DestCopyIndex = LIS->getInstructionIndex(NewInstr);
     if (IncomingReg) {
       // Add the region from the beginning of MBB to the copy instruction to
       // IncomingReg's live interval.
-      LiveInterval &IncomingLI = LIS->getOrCreateInterval(IncomingReg);
+      LiveInterval &IncomingLI = LIS->createEmptyInterval(IncomingReg);
       VNInfo *IncomingVNI = IncomingLI.getVNInfoAt(MBBStartIndex);
       if (!IncomingVNI)
         IncomingVNI = IncomingLI.getNextValue(MBBStartIndex,
                                               LIS->getVNInfoAllocator());
-      IncomingLI.addRange(LiveRange(MBBStartIndex,
-                                    DestCopyIndex.getRegSlot(),
-                                    IncomingVNI));
+      IncomingLI.addSegment(LiveInterval::Segment(MBBStartIndex,
+                                                  DestCopyIndex.getRegSlot(),
+                                                  IncomingVNI));
     }
 
-    LiveInterval &DestLI = LIS->getOrCreateInterval(DestReg);
-    if (NewInstr->getOperand(0).isDead()) {
+    LiveInterval &DestLI = LIS->getInterval(DestReg);
+    assert(DestLI.begin() != DestLI.end() &&
+           "PHIs should have nonempty LiveIntervals.");
+    if (DestLI.endIndex().isDead()) {
       // A dead PHI's live range begins and ends at the start of the MBB, but
       // the lowered copy, which will still be dead, needs to begin and end at
       // the copy instruction.
       VNInfo *OrigDestVNI = DestLI.getVNInfoAt(MBBStartIndex);
       assert(OrigDestVNI && "PHI destination should be live at block entry.");
-      DestLI.removeRange(MBBStartIndex, MBBStartIndex.getDeadSlot());
+      DestLI.removeSegment(MBBStartIndex, MBBStartIndex.getDeadSlot());
       DestLI.createDeadDef(DestCopyIndex.getRegSlot(),
                            LIS->getVNInfoAllocator());
       DestLI.removeValNo(OrigDestVNI);
     } else {
       // Otherwise, remove the region from the beginning of MBB to the copy
       // instruction from DestReg's live interval.
-      DestLI.removeRange(MBBStartIndex, DestCopyIndex.getRegSlot());
+      DestLI.removeSegment(MBBStartIndex, DestCopyIndex.getRegSlot());
       VNInfo *DestVNI = DestLI.getVNInfoAt(DestCopyIndex.getRegSlot());
       assert(DestVNI && "PHI destination should be live at its definition.");
       DestVNI->def = DestCopyIndex.getRegSlot();
@@ -457,7 +460,7 @@ void PHIElimination::LowerPHINode(MachineBasicBlock &MBB,
     if (LIS) {
       if (NewSrcInstr) {
         LIS->InsertMachineInstrInMaps(NewSrcInstr);
-        LIS->addLiveRangeToEndOfBlock(IncomingReg, NewSrcInstr);
+        LIS->addSegmentToEndOfBlock(IncomingReg, NewSrcInstr);
       }
 
       if (!SrcUndef &&
@@ -467,7 +470,11 @@ void PHIElimination::LowerPHINode(MachineBasicBlock &MBB,
         bool isLiveOut = false;
         for (MachineBasicBlock::succ_iterator SI = opBlock.succ_begin(),
              SE = opBlock.succ_end(); SI != SE; ++SI) {
-          if (SrcLI.liveAt(LIS->getMBBStartIdx(*SI))) {
+          SlotIndex startIdx = LIS->getMBBStartIdx(*SI);
+          VNInfo *VNI = SrcLI.getVNInfoAt(startIdx);
+
+          // Definitions by other PHIs are not truly live-in for our purposes.
+          if (VNI && VNI->def != startIdx) {
             isLiveOut = true;
             break;
           }
@@ -504,8 +511,8 @@ void PHIElimination::LowerPHINode(MachineBasicBlock &MBB,
                  "Cannot find kill instruction");
 
           SlotIndex LastUseIndex = LIS->getInstructionIndex(KillInst);
-          SrcLI.removeRange(LastUseIndex.getRegSlot(),
-                            LIS->getMBBEndIdx(&opBlock));
+          SrcLI.removeSegment(LastUseIndex.getRegSlot(),
+                              LIS->getMBBEndIdx(&opBlock));
         }
       }
     }