Minimize the slot indexes spanned by register ranges created when splitting.

When an interfering live range ends at a dead slot index between two
instructions, make sure that the inserted copy instruction gets a slot index
after the dead ones. This makes it possible to avoid the interference.

Ideally, there shouldn't be interference ending at a deleted instruction, but
physical register coalescing can sometimes do that to sub-registers.

This fixes PR9823.

llvm-svn: 130687

1 files changed, 4 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/LiveRangeEdit.cpp b/llvm/lib/CodeGen/LiveRangeEdit.cpp
index 443cc2e9048..f8a3dbb5fd7 100644
--- a/llvm/lib/CodeGen/LiveRangeEdit.cpp
+++ b/llvm/lib/CodeGen/LiveRangeEdit.cpp
@@ -140,11 +140,13 @@ SlotIndex LiveRangeEdit::rematerializeAt(MachineBasicBlock &MBB,
                                          const Remat &RM,
                                          LiveIntervals &lis,
                                          const TargetInstrInfo &tii,
-                                         const TargetRegisterInfo &tri) {
+                                         const TargetRegisterInfo &tri,
+                                         bool Late) {
   assert(RM.OrigMI && "Invalid remat");
   tii.reMaterialize(MBB, MI, DestReg, 0, RM.OrigMI, tri);
   rematted_.insert(RM.ParentVNI);
-  return lis.InsertMachineInstrInMaps(--MI).getDefIndex();
+  return lis.getSlotIndexes()->insertMachineInstrInMaps(--MI, Late)
+           .getDefIndex();
 }
 
 void LiveRangeEdit::eraseVirtReg(unsigned Reg, LiveIntervals &LIS) {