1 files changed, 14 insertions, 6 deletions
diff --git a/lib/CodeGen/InlineSpiller.cpp b/lib/CodeGen/InlineSpiller.cpp
index a1bd972..38e6c85 100644
--- a/lib/CodeGen/InlineSpiller.cpp
+++ b/lib/CodeGen/InlineSpiller.cpp
@@ -102,8 +102,7 @@ Spiller *createInlineSpiller(MachineFunctionPass &pass,
 }
 }
 
-/// reMaterializeFor - Attempt to rematerialize edit_->getReg() before MI instead of
-/// reloading it.
+/// reMaterializeFor - Attempt to rematerialize before MI instead of reloading.
 bool InlineSpiller::reMaterializeFor(MachineBasicBlock::iterator MI) {
   SlotIndex UseIdx = lis_.getInstructionIndex(MI).getUseIndex();
   VNInfo *OrigVNI = edit_->getParent().getVNInfoAt(UseIdx);
@@ -346,7 +345,8 @@ void InlineSpiller::spill(LiveRangeEdit &edit) {
          && "Trying to spill a stack slot.");
   DEBUG(dbgs() << "Inline spilling "
                << mri_.getRegClass(edit.getReg())->getName()
-               << ':' << edit.getParent() << "\n");
+               << ':' << edit.getParent() << "\nFrom original "
+               << PrintReg(vrm_.getOriginal(edit.getReg())) << '\n');
   assert(edit.getParent().isSpillable() &&
          "Attempting to spill already spilled value.");
 
@@ -357,12 +357,20 @@ void InlineSpiller::spill(LiveRangeEdit &edit) {
     return;
 
   rc_ = mri_.getRegClass(edit.getReg());
-  stackSlot_ = vrm_.assignVirt2StackSlot(edit_->getReg());
+
+  // Share a stack slot among all descendants of Orig.
+  unsigned Orig = vrm_.getOriginal(edit.getReg());
+  stackSlot_ = vrm_.getStackSlot(Orig);
+  if (stackSlot_ == VirtRegMap::NO_STACK_SLOT)
+    stackSlot_ = vrm_.assignVirt2StackSlot(Orig);
+
+  if (Orig != edit.getReg())
+    vrm_.assignVirt2StackSlot(edit.getReg(), stackSlot_);
 
   // Update LiveStacks now that we are committed to spilling.
   LiveInterval &stacklvr = lss_.getOrCreateInterval(stackSlot_, rc_);
-  assert(stacklvr.empty() && "Just created stack slot not empty");
-  stacklvr.getNextValue(SlotIndex(), 0, lss_.getVNInfoAllocator());
+  if (!stacklvr.hasAtLeastOneValue())
+    stacklvr.getNextValue(SlotIndex(), 0, lss_.getVNInfoAllocator());
   stacklvr.MergeRangesInAsValue(edit_->getParent(), stacklvr.getValNumInfo(0));
 
   // Iterate over instructions using register.