2 files changed, 61 insertions, 8 deletions

diff --git a/llvm/lib/CodeGen/LiveInterval.cpp b/llvm/lib/CodeGen/LiveInterval.cpp
index 40f8cd4388d..75cd36dec2c 100644
--- a/llvm/lib/CodeGen/LiveInterval.cpp
+++ b/llvm/lib/CodeGen/LiveInterval.cpp
@@ -551,6 +551,20 @@ void LiveInterval::MergeValueInAsValue(const LiveInterval &RHS,
   }
 }
 
+VNInfo *LiveInterval::getUnknownValNo(BumpPtrAllocator &VNInfoAllocator) {
+  unsigned i = getNumValNums();
+  if (i) {
+    do {
+      --i;
+      VNInfo *VNI = getValNumInfo(i);
+      if (VNI->def == ~0U && !VNI->copy &&
+          !VNI->hasPHIKill && !VNI->redefByEC && VNI->kills.empty())
+        return VNI;
+    } while (i != 0);
+  }
+  return getNextValue(~0U, 0, VNInfoAllocator);
+}
+
 
 /// MergeInClobberRanges - For any live ranges that are not defined in the
 /// current interval, but are defined in the Clobbers interval, mark them
@@ -561,8 +575,7 @@ void LiveInterval::MergeInClobberRanges(const LiveInterval &Clobbers,
   
   // Find a value # to use for the clobber ranges.  If there is already a value#
   // for unknown values, use it.
-  // FIXME: Use a single sentinal number for these!
-  VNInfo *ClobberValNo = getNextValue(~0U, 0, VNInfoAllocator);
+  VNInfo *ClobberValNo = getUnknownValNo(VNInfoAllocator);
   
   iterator IP = begin();
   for (const_iterator I = Clobbers.begin(), E = Clobbers.end(); I != E; ++I) {
@@ -587,6 +600,32 @@ void LiveInterval::MergeInClobberRanges(const LiveInterval &Clobbers,
   }
 }
 
+void LiveInterval::MergeInClobberRange(unsigned Start, unsigned End,
+                                       BumpPtrAllocator &VNInfoAllocator) {
+  // Find a value # to use for the clobber ranges.  If there is already a value#
+  // for unknown values, use it.
+  VNInfo *ClobberValNo = getUnknownValNo(VNInfoAllocator);
+  
+  iterator IP = begin();
+  IP = std::upper_bound(IP, end(), Start);
+    
+  // If the start of this range overlaps with an existing liverange, trim it.
+  if (IP != begin() && IP[-1].end > Start) {
+    Start = IP[-1].end;
+    // Trimmed away the whole range?
+    if (Start >= End) return;
+  }
+  // If the end of this range overlaps with an existing liverange, trim it.
+  if (IP != end() && End > IP->start) {
+    End = IP->start;
+    // If this trimmed away the whole range, ignore it.
+    if (Start == End) return;
+  }
+    
+  // Insert the clobber interval.
+  addRangeFrom(LiveRange(Start, End, ClobberValNo), IP);
+}
+
 /// MergeValueNumberInto - This method is called when two value nubmers
 /// are found to be equivalent.  This eliminates V1, replacing all
 /// LiveRanges with the V1 value number with the V2 value number.  This can
diff --git a/llvm/lib/CodeGen/SimpleRegisterCoalescing.cpp b/llvm/lib/CodeGen/SimpleRegisterCoalescing.cpp
index 942d8d95cf9..c29ee62c83e 100644
--- a/llvm/lib/CodeGen/SimpleRegisterCoalescing.cpp
+++ b/llvm/lib/CodeGen/SimpleRegisterCoalescing.cpp
@@ -193,13 +193,12 @@ bool SimpleRegisterCoalescing::AdjustCopiesBackFrom(LiveInterval &IntA,
   IntB.addRange(LiveRange(FillerStart, FillerEnd, BValNo));
 
   // If the IntB live range is assigned to a physical register, and if that
-  // physreg has aliases, 
+  // physreg has sub-registers, update their live intervals as well. 
   if (TargetRegisterInfo::isPhysicalRegister(IntB.reg)) {
-    // Update the liveintervals of sub-registers.
-    for (const unsigned *AS = tri_->getSubRegisters(IntB.reg); *AS; ++AS) {
-      LiveInterval &AliasLI = li_->getInterval(*AS);
-      AliasLI.addRange(LiveRange(FillerStart, FillerEnd,
-              AliasLI.getNextValue(FillerStart, 0, li_->getVNInfoAllocator())));
+    for (const unsigned *SR = tri_->getSubRegisters(IntB.reg); *SR; ++SR) {
+      LiveInterval &SRLI = li_->getInterval(*SR);
+      SRLI.addRange(LiveRange(FillerStart, FillerEnd,
+                 SRLI.getNextValue(FillerStart, 0, li_->getVNInfoAllocator())));
     }
   }
 
@@ -367,6 +366,9 @@ bool SimpleRegisterCoalescing::RemoveCopyByCommutingDef(LiveInterval &IntA,
     BExtend[ALR->end] = BLR->end;
 
   // Update uses of IntA of the specific Val# with IntB.
+  bool BHasSubRegs = false;
+  if (TargetRegisterInfo::isPhysicalRegister(IntB.reg))
+    BHasSubRegs = *tri_->getSubRegisters(IntB.reg);
   for (MachineRegisterInfo::use_iterator UI = mri_->use_begin(IntA.reg),
          UE = mri_->use_end(); UI != UE;) {
     MachineOperand &UseMO = UI.getOperand();
@@ -398,6 +400,9 @@ bool SimpleRegisterCoalescing::RemoveCopyByCommutingDef(LiveInterval &IntA,
       const LiveRange *DLR = IntB.getLiveRangeContaining(DefIdx);
       BHasPHIKill |= DLR->valno->hasPHIKill;
       assert(DLR->valno->def == DefIdx);
+      if (BHasSubRegs)
+        // Don't know how to update sub-register live intervals.
+        return false;
       BDeadValNos.push_back(DLR->valno);
       BExtend[DLR->start] = DLR->end;
       JoinedCopies.insert(UseMI);
@@ -435,6 +440,15 @@ bool SimpleRegisterCoalescing::RemoveCopyByCommutingDef(LiveInterval &IntA,
     if (EI != BExtend.end())
       End = EI->second;
     IntB.addRange(LiveRange(AI->start, End, ValNo));
+
+    // If the IntB live range is assigned to a physical register, and if that
+    // physreg has sub-registers, update their live intervals as well. 
+    if (TargetRegisterInfo::isPhysicalRegister(IntB.reg)) {
+      for (const unsigned *SR = tri_->getSubRegisters(IntB.reg); *SR; ++SR) {
+        LiveInterval &SRLI = li_->getInterval(*SR);
+        SRLI.MergeInClobberRange(AI->start, End, li_->getVNInfoAllocator());
+      }
+    }
   }
   IntB.addKills(ValNo, BKills);
   ValNo->hasPHIKill = BHasPHIKill;