When spilling a register defined by an early clobber, make sure that the new

live ranges for the spill register are also defined at the use slot instead of
the normal def slot.

This fixes PR8612 for the inline spiller. A use was being allocated to the same
register as a spilled early clobber def.

This problem exists in all the spillers. A fix for the standard spiller is
forthcoming.

llvm-svn: 119182

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/InlineSpiller.cpp b/llvm/lib/CodeGen/InlineSpiller.cpp
index 0e8f302b6a0..7e4fbadea4a 100644
--- a/llvm/lib/CodeGen/InlineSpiller.cpp
+++ b/llvm/lib/CodeGen/InlineSpiller.cpp
@@ -343,7 +343,13 @@ void InlineSpiller::insertReload(LiveInterval &NewLI,
 void InlineSpiller::insertSpill(LiveInterval &NewLI,
                                 MachineBasicBlock::iterator MI) {
   MachineBasicBlock &MBB = *MI->getParent();
+
+  // Get the defined value. It could be an early clobber so keep the def index.
   SlotIndex Idx = lis_.getInstructionIndex(MI).getDefIndex();
+  VNInfo *VNI = edit_->getParent().getVNInfoAt(Idx);
+  assert(VNI && VNI->def.getDefIndex() == Idx && "Inconsistent VNInfo");
+  Idx = VNI->def;
+
   tii_.storeRegToStackSlot(MBB, ++MI, NewLI.reg, true, stackSlot_, rc_, &tri_);
   --MI; // Point to store instruction.
   SlotIndex StoreIdx = lis_.InsertMachineInstrInMaps(MI).getDefIndex();