From 3d4114c464d1ec6c9a6088e04d2156f72c4b42ce Mon Sep 17 00:00:00 2001
From: Jakob Stoklund Olesen <stoklund@2pi.dk>
Date: Mon, 1 Nov 2010 23:59:48 +0000
Subject: [PATCH] When inserting copies during splitting, always use the parent
 register as the source, and let rewrite() clean it up.

This way, kill flags on the inserted copies are fixed as well during rewrite().

We can't just assume that all the copies we insert are going to be kills since
critical edges into loop headers sometimes require both source and dest to be
live out of a block.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117980 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SplitKit.cpp | 23 ++++++++++-------------
 lib/CodeGen/SplitKit.h   | 12 ++++++------
 2 files changed, 16 insertions(+), 19 deletions(-)

diff --git a/lib/CodeGen/SplitKit.cpp b/lib/CodeGen/SplitKit.cpp
index f8be7d484fe..5b9eaebeca6 100644
--- a/lib/CodeGen/SplitKit.cpp
+++ b/lib/CodeGen/SplitKit.cpp
@@ -659,13 +659,13 @@ void LiveIntervalMap::addRange(SlotIndex Start, SlotIndex End) {
     addSimpleRange(I->start, std::min(End, I->end), I->valno);
 }
 
-VNInfo *LiveIntervalMap::defByCopyFrom(unsigned Reg,
-                                       const VNInfo *ParentVNI,
-                                       MachineBasicBlock &MBB,
-                                       MachineBasicBlock::iterator I) {
+VNInfo *LiveIntervalMap::defByCopy(const VNInfo *ParentVNI,
+                                   MachineBasicBlock &MBB,
+                                   MachineBasicBlock::iterator I) {
   const TargetInstrDesc &TID = MBB.getParent()->getTarget().getInstrInfo()->
     get(TargetOpcode::COPY);
-  MachineInstr *MI = BuildMI(MBB, I, DebugLoc(), TID, li_->reg).addReg(Reg);
+  MachineInstr *MI = BuildMI(MBB, I, DebugLoc(), TID, li_->reg)
+    .addReg(parentli_.reg);
   SlotIndex DefIdx = lis_.InsertMachineInstrInMaps(MI).getDefIndex();
   VNInfo *VNI = defValue(ParentVNI, DefIdx);
   VNI->setCopy(MI);
@@ -723,8 +723,7 @@ void SplitEditor::enterIntvBefore(SlotIndex Idx) {
   truncatedValues.insert(ParentVNI);
   MachineInstr *MI = lis_.getInstructionFromIndex(Idx);
   assert(MI && "enterIntvBefore called with invalid index");
-  VNInfo *VNI = openli_.defByCopyFrom(edit_.getReg(), ParentVNI,
-                                      *MI->getParent(), MI);
+  VNInfo *VNI = openli_.defByCopy(ParentVNI, *MI->getParent(), MI);
   openli_.getLI()->addRange(LiveRange(VNI->def, Idx.getDefIndex(), VNI));
   DEBUG(dbgs() << ": " << *openli_.getLI() << '\n');
 }
@@ -741,8 +740,7 @@ void SplitEditor::enterIntvAtEnd(MachineBasicBlock &MBB) {
   }
   DEBUG(dbgs() << ": valno " << ParentVNI->id);
   truncatedValues.insert(ParentVNI);
-  VNInfo *VNI = openli_.defByCopyFrom(edit_.getReg(), ParentVNI,
-                                      MBB, MBB.getFirstTerminator());
+  VNInfo *VNI = openli_.defByCopy(ParentVNI, MBB, MBB.getFirstTerminator());
   // Make sure openli is live out of MBB.
   openli_.getLI()->addRange(LiveRange(VNI->def, End, VNI));
   DEBUG(dbgs() << ": " << *openli_.getLI() << '\n');
@@ -775,8 +773,7 @@ void SplitEditor::leaveIntvAfter(SlotIndex Idx) {
 
   MachineBasicBlock::iterator MII = lis_.getInstructionFromIndex(Idx);
   MachineBasicBlock *MBB = MII->getParent();
-  VNInfo *VNI = dupli_.defByCopyFrom(openli_.getLI()->reg, ParentVNI, *MBB,
-                                     llvm::next(MII));
+  VNInfo *VNI = dupli_.defByCopy(ParentVNI, *MBB, llvm::next(MII));
 
   // Finally we must make sure that openli is properly extended from Idx to the
   // new copy.
@@ -798,8 +795,8 @@ void SplitEditor::leaveIntvAtTop(MachineBasicBlock &MBB) {
   }
 
   // We are going to insert a back copy, so we must have a dupli_.
-  VNInfo *VNI = dupli_.defByCopyFrom(openli_.getLI()->reg, ParentVNI,
-                                     MBB, MBB.SkipPHIsAndLabels(MBB.begin()));
+  VNInfo *VNI = dupli_.defByCopy(ParentVNI, MBB,
+                                 MBB.SkipPHIsAndLabels(MBB.begin()));
 
   // Finally we must make sure that openli is properly extended from Start to
   // the new copy.
diff --git a/lib/CodeGen/SplitKit.h b/lib/CodeGen/SplitKit.h
index 9a7fa5388a1..395df75c5c5 100644
--- a/lib/CodeGen/SplitKit.h
+++ b/lib/CodeGen/SplitKit.h
@@ -246,12 +246,12 @@ public:
   /// beforehand so mapValue will work.
   void addRange(SlotIndex Start, SlotIndex End);
 
-  /// defByCopyFrom - Insert a copy from Reg to li, assuming that Reg carries
-  /// ParentVNI. Add a minimal live range for the new value and return it.
-  VNInfo *defByCopyFrom(unsigned Reg,
-                        const VNInfo *ParentVNI,
-                        MachineBasicBlock &MBB,
-                        MachineBasicBlock::iterator I);
+  /// defByCopy- Insert a copy from parentli to li, assuming that ParentVNI is
+  /// live at the insert location. Add a minimal live range for the new value
+  /// and return it.
+  VNInfo *defByCopy(const VNInfo *ParentVNI,
+                    MachineBasicBlock &MBB,
+                    MachineBasicBlock::iterator I);
 
 };