Revert "Revert "Lift the spill at each irreducible loop block restriction.""
This reverts commit 2818dbcd75ea9beadcba9d18e2f68523108d0cf5.
Change-Id: I92b2b60b4f08f50cacfea4132f1c28cfbd628f1a
diff --git a/compiler/optimizing/graph_visualizer.cc b/compiler/optimizing/graph_visualizer.cc
index 2805162..9d796c1 100644
--- a/compiler/optimizing/graph_visualizer.cc
+++ b/compiler/optimizing/graph_visualizer.cc
@@ -507,6 +507,7 @@
|| IsPass(HDeadCodeElimination::kFinalDeadCodeEliminationPassName)
|| IsPass(HDeadCodeElimination::kInitialDeadCodeEliminationPassName)
|| IsPass(BoundsCheckElimination::kBoundsCheckEliminationPassName)
+ || IsPass(RegisterAllocator::kRegisterAllocatorPassName)
|| IsPass(SsaBuilder::kSsaBuilderPassName)) {
HLoopInformation* info = instruction->GetBlock()->GetLoopInformation();
if (info == nullptr) {
diff --git a/compiler/optimizing/register_allocator.cc b/compiler/optimizing/register_allocator.cc
index d77639d..5cd30ad 100644
--- a/compiler/optimizing/register_allocator.cc
+++ b/compiler/optimizing/register_allocator.cc
@@ -179,7 +179,7 @@
}
if (block->IsCatchBlock() ||
- (block->GetLoopInformation() != nullptr && block->GetLoopInformation()->IsIrreducible())) {
+ (block->IsLoopHeader() && block->GetLoopInformation()->IsIrreducible())) {
// By blocking all registers at the top of each catch block or irreducible loop, we force
// intervals belonging to the live-in set of the catch/header block to be spilled.
// TODO(ngeoffray): Phis in this block could be allocated in register.
@@ -1749,8 +1749,10 @@
}
// Find the intervals that cover `from` and `to`.
- LiveInterval* destination = interval->GetSiblingAt(to->GetLifetimeStart());
- LiveInterval* source = interval->GetSiblingAt(from->GetLifetimeEnd() - 1);
+ size_t destination_position = to->GetLifetimeStart();
+ size_t source_position = from->GetLifetimeEnd() - 1;
+ LiveInterval* destination = interval->GetSiblingAt(destination_position);
+ LiveInterval* source = interval->GetSiblingAt(source_position);
if (destination == source) {
// Interval was not split.
@@ -1759,7 +1761,8 @@
LiveInterval* parent = interval->GetParent();
HInstruction* defined_by = parent->GetDefinedBy();
- if (destination == nullptr) {
+ if (codegen_->GetGraph()->HasIrreducibleLoops() &&
+ (destination == nullptr || !destination->CoversSlow(destination_position))) {
// Our live_in fixed point calculation has found that the instruction is live
// in the `to` block because it will eventually enter an irreducible loop. Our
// live interval computation however does not compute a fixed point, and
@@ -1775,18 +1778,41 @@
return;
}
+ Location location_source;
+ // `GetSiblingAt` returns the interval whose start and end cover `position`,
+ // but does not check whether the interval is inactive at that position.
+ // The only situation where the interval is inactive at that position is in the
+ // presence of irreducible loops for constants and ArtMethod.
+ if (codegen_->GetGraph()->HasIrreducibleLoops() &&
+ (source == nullptr || !source->CoversSlow(source_position))) {
+ DCHECK(IsMaterializableEntryBlockInstructionOfGraphWithIrreducibleLoop(defined_by));
+ if (defined_by->IsConstant()) {
+ location_source = defined_by->GetLocations()->Out();
+ } else {
+ DCHECK(defined_by->IsCurrentMethod());
+ location_source = parent->NeedsTwoSpillSlots()
+ ? Location::DoubleStackSlot(parent->GetSpillSlot())
+ : Location::StackSlot(parent->GetSpillSlot());
+ }
+ } else {
+ DCHECK(source != nullptr);
+ DCHECK(source->CoversSlow(source_position));
+ DCHECK(destination->CoversSlow(destination_position));
+ location_source = source->ToLocation();
+ }
+
// If `from` has only one successor, we can put the moves at the exit of it. Otherwise
// we need to put the moves at the entry of `to`.
if (from->GetNormalSuccessors().size() == 1) {
InsertParallelMoveAtExitOf(from,
defined_by,
- source->ToLocation(),
+ location_source,
destination->ToLocation());
} else {
DCHECK_EQ(to->GetPredecessors().size(), 1u);
InsertParallelMoveAtEntryOf(to,
defined_by,
- source->ToLocation(),
+ location_source,
destination->ToLocation());
}
}
@@ -1890,7 +1916,7 @@
for (HLinearOrderIterator it(*codegen_->GetGraph()); !it.Done(); it.Advance()) {
HBasicBlock* block = it.Current();
if (block->IsCatchBlock() ||
- (block->GetLoopInformation() != nullptr && block->GetLoopInformation()->IsIrreducible())) {
+ (block->IsLoopHeader() && block->GetLoopInformation()->IsIrreducible())) {
// Instructions live at the top of catch blocks or irreducible loop header
// were forced to spill.
if (kIsDebugBuild) {