From 8af1e761f824ca46088780c2fbe1de9e4278f06c Mon Sep 17 00:00:00 2001
From: Owen Anderson <resistor@mac.com>
Date: Mon, 26 Jan 2009 19:12:06 +0000
Subject: [PATCH] Fix an issue where LiveIntervals was trying to be smart about
 removing kill markers, and ended up foiling the interval reconstruction.

This allows us to turn on reconstruction in the pre alloc splitter, which
fixes a number of miscompilations.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63025 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/PreAllocSplitting.cpp | 46 ++++++++-----------------------
 1 file changed, 12 insertions(+), 34 deletions(-)

diff --git a/lib/CodeGen/PreAllocSplitting.cpp b/lib/CodeGen/PreAllocSplitting.cpp
index 16a9e6d9b04..0325f7cd02b 100644
--- a/lib/CodeGen/PreAllocSplitting.cpp
+++ b/lib/CodeGen/PreAllocSplitting.cpp
@@ -748,12 +748,12 @@ VNInfo* PreAllocSplitting::PerformPHIConstruction(
     ret = PerformPHIConstruction(walker, MBB, LI, Visited, Defs, Uses,
                                  NewVNs, LiveOut, Phis, false, true);
     
+    LI->addRange(LiveRange(UseIndex, EndIndex+1, ret));
+    
     // FIXME: Need to set kills properly for inter-block stuff.
     if (LI->isKill(ret, UseIndex)) LI->removeKill(ret, UseIndex);
     if (intrablock)
       LI->addKill(ret, EndIndex);
-    
-    LI->addRange(LiveRange(UseIndex, EndIndex+1, ret));
   } else if (ContainsDefs && ContainsUses){
     SmallPtrSet<MachineInstr*, 2>& BlockDefs = Defs[MBB];
     SmallPtrSet<MachineInstr*, 2>& BlockUses = Uses[MBB];
@@ -805,13 +805,13 @@ VNInfo* PreAllocSplitting::PerformPHIConstruction(
       ret = PerformPHIConstruction(walker, MBB, LI, Visited, Defs, Uses,
                                    NewVNs, LiveOut, Phis, false, true);
 
+    LI->addRange(LiveRange(StartIndex, EndIndex+1, ret));
+    
     if (foundUse && LI->isKill(ret, StartIndex))
       LI->removeKill(ret, StartIndex);
     if (intrablock) {
       LI->addKill(ret, EndIndex);
     }
-
-    LI->addRange(LiveRange(StartIndex, EndIndex+1, ret));
   }
   
   // Memoize results so we don't have to recompute them.
@@ -1131,18 +1131,10 @@ bool PreAllocSplitting::Rematerialize(unsigned vreg, VNInfo* ValNo,
   TII->reMaterialize(MBB, RestorePt, vreg, DefMI);
   LIs->InsertMachineInstrInMaps(prior(RestorePt), RestoreIdx);
   
-  if (KillPt->getParent() == BarrierMBB) {
-    VNInfo* After = UpdateRegisterInterval(ValNo, LIs->getUseIndex(KillIdx)+1,
-                           LIs->getDefIndex(RestoreIdx));
-    
-    RenumberValno(After);
-
-    ++NumSplits;
-    ++NumRemats;
-    return true;
-  }
-
-  RepairLiveInterval(CurrLI, ValNo, DefMI, RestoreIdx);
+  ReconstructLiveInterval(CurrLI);
+  unsigned RematIdx = LIs->getInstructionIndex(prior(RestorePt));
+  RematIdx = LiveIntervals::getDefIndex(RematIdx);
+  RenumberValno(CurrLI->findDefinedVNInfo(RematIdx));
   
   ++NumSplits;
   ++NumRemats;
@@ -1315,28 +1307,14 @@ bool PreAllocSplitting::SplitRegLiveInterval(LiveInterval *LI) {
   MachineInstr *LoadMI = prior(RestorePt);
   LIs->InsertMachineInstrInMaps(LoadMI, RestoreIndex);
 
-  // If live interval is spilled in the same block as the barrier, just
-  // create a hole in the interval.
-  if (!DefMBB ||
-      (SpillMI && SpillMI->getParent() == BarrierMBB)) {
-    // Update spill stack slot live interval.
-    UpdateSpillSlotInterval(ValNo, LIs->getUseIndex(SpillIndex)+1,
-                            LIs->getDefIndex(RestoreIndex));
-
-    VNInfo* After = UpdateRegisterInterval(ValNo,
-                           LIs->getUseIndex(SpillIndex)+1,
-                           LIs->getDefIndex(RestoreIndex));
-    RenumberValno(After);
-   
-    ++NumSplits;
-    return true;
-  }
-
   // Update spill stack slot live interval.
   UpdateSpillSlotInterval(ValNo, LIs->getUseIndex(SpillIndex)+1,
                           LIs->getDefIndex(RestoreIndex));
 
-  RepairLiveInterval(CurrLI, ValNo, DefMI, RestoreIndex);
+  ReconstructLiveInterval(CurrLI);
+  unsigned RestoreIdx = LIs->getInstructionIndex(prior(RestorePt));
+  RestoreIdx = LiveIntervals::getDefIndex(RestoreIdx);
+  RenumberValno(CurrLI->findDefinedVNInfo(RestoreIdx));
   
   ++NumSplits;
   return true;