ARM: VIXL32: Improve BoundsCheck for constant inputs.
Test: mma test-art-host && mma test-art-target
Change-Id: I05051c03dbd3684c674096def84020494d28364b
diff --git a/compiler/optimizing/code_generator_arm.cc b/compiler/optimizing/code_generator_arm.cc
index bab626f..ff19ab1 100644
--- a/compiler/optimizing/code_generator_arm.cc
+++ b/compiler/optimizing/code_generator_arm.cc
@@ -6217,21 +6217,59 @@
caller_saves.Add(Location::RegisterLocation(calling_convention.GetRegisterAt(0)));
caller_saves.Add(Location::RegisterLocation(calling_convention.GetRegisterAt(1)));
LocationSummary* locations = codegen_->CreateThrowingSlowPathLocations(instruction, caller_saves);
- locations->SetInAt(0, Location::RequiresRegister());
- locations->SetInAt(1, Location::RequiresRegister());
+
+ HInstruction* index = instruction->InputAt(0);
+ HInstruction* length = instruction->InputAt(1);
+ // If both index and length are constants we can statically check the bounds. But if at least one
+ // of them is not encodable ArmEncodableConstantOrRegister will create
+ // Location::RequiresRegister() which is not desired to happen. Instead we create constant
+ // locations.
+ bool both_const = index->IsConstant() && length->IsConstant();
+ locations->SetInAt(0, both_const
+ ? Location::ConstantLocation(index->AsConstant())
+ : ArmEncodableConstantOrRegister(index, CMP));
+ locations->SetInAt(1, both_const
+ ? Location::ConstantLocation(length->AsConstant())
+ : ArmEncodableConstantOrRegister(length, CMP));
}
void InstructionCodeGeneratorARM::VisitBoundsCheck(HBoundsCheck* instruction) {
LocationSummary* locations = instruction->GetLocations();
- SlowPathCodeARM* slow_path =
- new (GetGraph()->GetArena()) BoundsCheckSlowPathARM(instruction);
- codegen_->AddSlowPath(slow_path);
+ Location index_loc = locations->InAt(0);
+ Location length_loc = locations->InAt(1);
- Register index = locations->InAt(0).AsRegister<Register>();
- Register length = locations->InAt(1).AsRegister<Register>();
+ if (length_loc.IsConstant()) {
+ int32_t length = helpers::Int32ConstantFrom(length_loc);
+ if (index_loc.IsConstant()) {
+ // BCE will remove the bounds check if we are guaranteed to pass.
+ int32_t index = helpers::Int32ConstantFrom(index_loc);
+ if (index < 0 || index >= length) {
+ SlowPathCodeARM* slow_path =
+ new (GetGraph()->GetArena()) BoundsCheckSlowPathARM(instruction);
+ codegen_->AddSlowPath(slow_path);
+ __ b(slow_path->GetEntryLabel());
+ } else {
+ // Some optimization after BCE may have generated this, and we should not
+ // generate a bounds check if it is a valid range.
+ }
+ return;
+ }
- __ cmp(index, ShifterOperand(length));
- __ b(slow_path->GetEntryLabel(), HS);
+ SlowPathCodeARM* slow_path = new (GetGraph()->GetArena()) BoundsCheckSlowPathARM(instruction);
+ __ cmp(index_loc.AsRegister<Register>(), ShifterOperand(length));
+ codegen_->AddSlowPath(slow_path);
+ __ b(slow_path->GetEntryLabel(), HS);
+ } else {
+ SlowPathCodeARM* slow_path = new (GetGraph()->GetArena()) BoundsCheckSlowPathARM(instruction);
+ if (index_loc.IsConstant()) {
+ int32_t index = helpers::Int32ConstantFrom(index_loc);
+ __ cmp(length_loc.AsRegister<Register>(), ShifterOperand(index));
+ } else {
+ __ cmp(length_loc.AsRegister<Register>(), ShifterOperand(index_loc.AsRegister<Register>()));
+ }
+ codegen_->AddSlowPath(slow_path);
+ __ b(slow_path->GetEntryLabel(), LS);
+ }
}
void CodeGeneratorARM::MarkGCCard(Register temp,
diff --git a/compiler/optimizing/code_generator_arm_vixl.cc b/compiler/optimizing/code_generator_arm_vixl.cc
index a1f30cd..fc62cf1 100644
--- a/compiler/optimizing/code_generator_arm_vixl.cc
+++ b/compiler/optimizing/code_generator_arm_vixl.cc
@@ -6264,20 +6264,56 @@
caller_saves.Add(LocationFrom(calling_convention.GetRegisterAt(0)));
caller_saves.Add(LocationFrom(calling_convention.GetRegisterAt(1)));
LocationSummary* locations = codegen_->CreateThrowingSlowPathLocations(instruction, caller_saves);
- locations->SetInAt(0, Location::RequiresRegister());
- locations->SetInAt(1, Location::RequiresRegister());
+
+ HInstruction* index = instruction->InputAt(0);
+ HInstruction* length = instruction->InputAt(1);
+ // If both index and length are constants we can statically check the bounds. But if at least one
+ // of them is not encodable ArmEncodableConstantOrRegister will create
+ // Location::RequiresRegister() which is not desired to happen. Instead we create constant
+ // locations.
+ bool both_const = index->IsConstant() && length->IsConstant();
+ locations->SetInAt(0, both_const
+ ? Location::ConstantLocation(index->AsConstant())
+ : ArmEncodableConstantOrRegister(index, CMP));
+ locations->SetInAt(1, both_const
+ ? Location::ConstantLocation(length->AsConstant())
+ : ArmEncodableConstantOrRegister(length, CMP));
}
void InstructionCodeGeneratorARMVIXL::VisitBoundsCheck(HBoundsCheck* instruction) {
- SlowPathCodeARMVIXL* slow_path =
- new (GetGraph()->GetArena()) BoundsCheckSlowPathARMVIXL(instruction);
- codegen_->AddSlowPath(slow_path);
+ LocationSummary* locations = instruction->GetLocations();
+ Location index_loc = locations->InAt(0);
+ Location length_loc = locations->InAt(1);
- vixl32::Register index = InputRegisterAt(instruction, 0);
- vixl32::Register length = InputRegisterAt(instruction, 1);
+ if (length_loc.IsConstant()) {
+ int32_t length = Int32ConstantFrom(length_loc);
+ if (index_loc.IsConstant()) {
+ // BCE will remove the bounds check if we are guaranteed to pass.
+ int32_t index = Int32ConstantFrom(index_loc);
+ if (index < 0 || index >= length) {
+ SlowPathCodeARMVIXL* slow_path =
+ new (GetGraph()->GetArena()) BoundsCheckSlowPathARMVIXL(instruction);
+ codegen_->AddSlowPath(slow_path);
+ __ B(slow_path->GetEntryLabel());
+ } else {
+ // Some optimization after BCE may have generated this, and we should not
+ // generate a bounds check if it is a valid range.
+ }
+ return;
+ }
- __ Cmp(index, length);
- __ B(hs, slow_path->GetEntryLabel());
+ SlowPathCodeARMVIXL* slow_path =
+ new (GetGraph()->GetArena()) BoundsCheckSlowPathARMVIXL(instruction);
+ __ Cmp(RegisterFrom(index_loc), length);
+ codegen_->AddSlowPath(slow_path);
+ __ B(hs, slow_path->GetEntryLabel());
+ } else {
+ SlowPathCodeARMVIXL* slow_path =
+ new (GetGraph()->GetArena()) BoundsCheckSlowPathARMVIXL(instruction);
+ __ Cmp(RegisterFrom(length_loc), InputOperandAt(instruction, 0));
+ codegen_->AddSlowPath(slow_path);
+ __ B(ls, slow_path->GetEntryLabel());
+ }
}
void CodeGeneratorARMVIXL::MarkGCCard(vixl32::Register temp,
