CHA guard optimization (elimination/hoisting).
Test: manual by checking the dump-cfg output.
Change-Id: I254e168b9a85d2d3d23e02eea7e129c1bc9ab920
diff --git a/compiler/optimizing/nodes.h b/compiler/optimizing/nodes.h
index 4a77bed..6cfaa86 100644
--- a/compiler/optimizing/nodes.h
+++ b/compiler/optimizing/nodes.h
@@ -330,6 +330,7 @@
invoke_type_(invoke_type),
in_ssa_form_(false),
should_generate_constructor_barrier_(should_generate_constructor_barrier),
+ number_of_cha_guards_(0),
instruction_set_(instruction_set),
cached_null_constant_(nullptr),
cached_int_constants_(std::less<int32_t>(), arena->Adapter(kArenaAllocConstantsMap)),
@@ -551,9 +552,7 @@
}
bool HasShouldDeoptimizeFlag() const {
- // TODO: if all CHA guards can be eliminated, there is no need for the flag
- // even if cha_single_implementation_list_ is not empty.
- return !cha_single_implementation_list_.empty();
+ return number_of_cha_guards_ != 0;
}
bool HasTryCatch() const { return has_try_catch_; }
@@ -572,6 +571,10 @@
ReferenceTypeInfo GetInexactObjectRti() const { return inexact_object_rti_; }
+ uint32_t GetNumberOfCHAGuards() { return number_of_cha_guards_; }
+ void SetNumberOfCHAGuards(uint32_t num) { number_of_cha_guards_ = num; }
+ void IncrementNumberOfCHAGuards() { number_of_cha_guards_++; }
+
private:
void RemoveInstructionsAsUsersFromDeadBlocks(const ArenaBitVector& visited) const;
void RemoveDeadBlocks(const ArenaBitVector& visited);
@@ -667,6 +670,10 @@
const bool should_generate_constructor_barrier_;
+ // Number of CHA guards in the graph. Used to short-circuit the
+ // CHA guard optimization pass when there is no CHA guard left.
+ uint32_t number_of_cha_guards_;
+
const InstructionSet instruction_set_;
// Cached constants.
@@ -2349,6 +2356,11 @@
class HVariableInputSizeInstruction : public HInstruction {
public:
+ using HInstruction::GetInputRecords; // Keep the const version visible.
+ ArrayRef<HUserRecord<HInstruction*>> GetInputRecords() OVERRIDE {
+ return ArrayRef<HUserRecord<HInstruction*>>(inputs_);
+ }
+
void AddInput(HInstruction* input);
void InsertInputAt(size_t index, HInstruction* input);
void RemoveInputAt(size_t index);
@@ -2489,11 +2501,6 @@
bool IsCatchPhi() const { return GetBlock()->IsCatchBlock(); }
- using HInstruction::GetInputRecords; // Keep the const version visible.
- ArrayRef<HUserRecord<HInstruction*>> GetInputRecords() OVERRIDE FINAL {
- return ArrayRef<HUserRecord<HInstruction*>>(inputs_);
- }
-
Primitive::Type GetType() const OVERRIDE { return GetPackedField<TypeField>(); }
void SetType(Primitive::Type new_type) {
// Make sure that only valid type changes occur. The following are allowed:
@@ -2925,14 +2932,20 @@
// if it's true, starts to do deoptimization.
// It has a 4-byte slot on stack.
// TODO: allocate a register for this flag.
-class HShouldDeoptimizeFlag FINAL : public HExpression<0> {
+class HShouldDeoptimizeFlag FINAL : public HVariableInputSizeInstruction {
public:
- // TODO: use SideEffects to aid eliminating some CHA guards.
- explicit HShouldDeoptimizeFlag(uint32_t dex_pc)
- : HExpression(Primitive::kPrimInt, SideEffects::None(), dex_pc) {
+ // CHA guards are only optimized in a separate pass and it has no side effects
+ // with regard to other passes.
+ HShouldDeoptimizeFlag(ArenaAllocator* arena, uint32_t dex_pc)
+ : HVariableInputSizeInstruction(SideEffects::None(), dex_pc, arena, 0, kArenaAllocCHA) {
}
- // We don't eliminate CHA guards yet.
+ Primitive::Type GetType() const OVERRIDE { return Primitive::kPrimInt; }
+
+ // We do all CHA guard elimination/motion in a single pass, after which there is no
+ // further guard elimination/motion since a guard might have been used for justification
+ // of the elimination of another guard. Therefore, we pretend this guard cannot be moved
+ // to avoid other optimizations trying to move it.
bool CanBeMoved() const OVERRIDE { return false; }
DECLARE_INSTRUCTION(ShouldDeoptimizeFlag);
@@ -3816,11 +3829,6 @@
public:
bool NeedsEnvironment() const OVERRIDE;
- using HInstruction::GetInputRecords; // Keep the const version visible.
- ArrayRef<HUserRecord<HInstruction*>> GetInputRecords() OVERRIDE {
- return ArrayRef<HUserRecord<HInstruction*>>(inputs_);
- }
-
void SetArgumentAt(size_t index, HInstruction* argument) {
SetRawInputAt(index, argument);
}