Spiller now remove unused spill slots.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47657 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index 716c370..00ba2e7 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -764,6 +764,9 @@
   MachineInstr *fmi = isSS ? tii_->foldMemoryOperand(*mf_, MI, FoldOps, Slot)
                            : tii_->foldMemoryOperand(*mf_, MI, FoldOps, DefMI);
   if (fmi) {
+    // Remember this instruction uses the spill slot.
+    if (isSS) vrm.addSpillSlotUse(Slot, fmi);
+
     // Attempt to fold the memory reference into the instruction. If
     // we can do this, we don't need to insert spill code.
     if (lv_)