Use the same spill slot for all live ranges that descend form the same original

register.

This avoids some silly stack slot shuffling when both sides of a copy get
spilled.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126353 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2011-02-24 01:07:55 +00:00
parent fae7f6de9e
commit b2597268c2

View File

@ -345,7 +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.");
@ -356,12 +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.