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Unified Diff: src/compiler/register-allocator.cc

Issue 2176173003: [Turbofan] Revert FP register aliasing support on Arm. (Closed) Base URL: https://chromium.googlesource.com/v8/v8.git@master
Patch Set: Back out float register slots for Arm. Created 4 years, 5 months ago
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Index: src/compiler/register-allocator.cc
diff --git a/src/compiler/register-allocator.cc b/src/compiler/register-allocator.cc
index 38e4a96b3b52c810bf87c1f5d80396d9e8a01cba..5e9631844ab52f618354f25ae60880dea858272c 100644
--- a/src/compiler/register-allocator.cc
+++ b/src/compiler/register-allocator.cc
@@ -33,7 +33,7 @@ int GetRegisterCount(const RegisterConfiguration* cfg, RegisterKind kind) {
int GetAllocatableRegisterCount(const RegisterConfiguration* cfg,
RegisterKind kind) {
- return kind == FP_REGISTERS ? cfg->num_allocatable_double_registers()
+ return kind == FP_REGISTERS ? cfg->num_allocatable_aliased_double_registers()
: cfg->num_allocatable_general_registers();
}
@@ -72,8 +72,14 @@ int GetByteWidth(MachineRepresentation rep) {
case MachineRepresentation::kWord16:
case MachineRepresentation::kWord32:
case MachineRepresentation::kTagged:
+ return kPointerSize;
case MachineRepresentation::kFloat32:
+// TODO(bbudge) Eliminate this when FP register aliasing works.
+#if V8_TARGET_ARCH_ARM
+ return 8;
Mircea Trofin 2016/07/27 23:29:31 isn't there a constant we could use instead of "8"
bbudge 2016/07/29 00:45:39 Fixed here and the rest too.
+#else
return kPointerSize;
+#endif
case MachineRepresentation::kWord64:
case MachineRepresentation::kFloat64:
return 8;
@@ -1335,12 +1341,8 @@ RegisterAllocationData::RegisterAllocationData(
allocation_zone()),
fixed_live_ranges_(this->config()->num_general_registers(), nullptr,
allocation_zone()),
- fixed_float_live_ranges_(this->config()->num_float_registers(), nullptr,
- allocation_zone()),
fixed_double_live_ranges_(this->config()->num_double_registers(), nullptr,
allocation_zone()),
- fixed_simd128_live_ranges_(this->config()->num_simd128_registers(),
- nullptr, allocation_zone()),
spill_ranges_(code->VirtualRegisterCount(), nullptr, allocation_zone()),
delayed_references_(allocation_zone()),
assigned_registers_(nullptr),
@@ -1518,21 +1520,8 @@ void RegisterAllocationData::MarkAllocated(MachineRepresentation rep,
int index) {
switch (rep) {
case MachineRepresentation::kFloat32:
- case MachineRepresentation::kSimd128:
- if (kSimpleFPAliasing) {
- assigned_double_registers_->Add(index);
- } else {
- int alias_base_index = -1;
- int aliases = config()->GetAliases(
- rep, index, MachineRepresentation::kFloat64, &alias_base_index);
- DCHECK(aliases > 0 || (aliases == 0 && alias_base_index == -1));
- while (aliases--) {
- int aliased_reg = alias_base_index + aliases;
- assigned_double_registers_->Add(aliased_reg);
- }
- }
- break;
case MachineRepresentation::kFloat64:
+ case MachineRepresentation::kSimd128:
assigned_double_registers_->Add(index);
break;
default:
@@ -1859,11 +1848,7 @@ int LiveRangeBuilder::FixedFPLiveRangeID(int index, MachineRepresentation rep) {
int result = -index - 1;
switch (rep) {
case MachineRepresentation::kSimd128:
- result -= config()->num_float_registers();
- // Fall through.
case MachineRepresentation::kFloat32:
- result -= config()->num_double_registers();
- // Fall through.
case MachineRepresentation::kFloat64:
result -= config()->num_general_registers();
break;
@@ -1893,18 +1878,8 @@ TopLevelLiveRange* LiveRangeBuilder::FixedFPLiveRangeFor(
TopLevelLiveRange* result = nullptr;
switch (rep) {
case MachineRepresentation::kFloat32:
- DCHECK(rep == MachineRepresentation::kFloat32);
- DCHECK(index < config()->num_float_registers());
- result = data()->fixed_float_live_ranges()[index];
- if (result == nullptr) {
- result = data()->NewLiveRange(FixedFPLiveRangeID(index, rep), rep);
- DCHECK(result->IsFixed());
- result->set_assigned_register(index);
- data()->MarkAllocated(rep, index);
- data()->fixed_float_live_ranges()[index] = result;
- }
- break;
case MachineRepresentation::kFloat64:
+ case MachineRepresentation::kSimd128:
DCHECK(index < config()->num_double_registers());
result = data()->fixed_double_live_ranges()[index];
if (result == nullptr) {
@@ -1915,17 +1890,6 @@ TopLevelLiveRange* LiveRangeBuilder::FixedFPLiveRangeFor(
data()->fixed_double_live_ranges()[index] = result;
}
break;
- case MachineRepresentation::kSimd128:
- DCHECK(index < config()->num_simd128_registers());
- result = data()->fixed_simd128_live_ranges()[index];
- if (result == nullptr) {
- result = data()->NewLiveRange(FixedFPLiveRangeID(index, rep), rep);
- DCHECK(result->IsFixed());
- result->set_assigned_register(index);
- data()->MarkAllocated(rep, index);
- data()->fixed_simd128_live_ranges()[index] = result;
- }
- break;
default:
UNREACHABLE();
break;
@@ -2052,7 +2016,8 @@ void LiveRangeBuilder::ProcessInstructions(const InstructionBlock* block,
}
if (instr->ClobbersDoubleRegisters()) {
- for (int i = 0; i < config()->num_allocatable_double_registers(); ++i) {
+ for (int i = 0; i < config()->num_allocatable_aliased_double_registers();
+ ++i) {
// Add a UseInterval for all DoubleRegisters. See comment above for
// general registers.
int code = config()->GetAllocatableDoubleCode(i);
@@ -2061,26 +2026,6 @@ void LiveRangeBuilder::ProcessInstructions(const InstructionBlock* block,
range->AddUseInterval(curr_position, curr_position.End(),
allocation_zone());
}
- // Preserve fixed float registers on archs with non-simple aliasing.
- if (!kSimpleFPAliasing) {
- for (int i = 0; i < config()->num_allocatable_float_registers(); ++i) {
- // Add a UseInterval for all FloatRegisters. See comment above for
- // general registers.
- int code = config()->GetAllocatableFloatCode(i);
- TopLevelLiveRange* range =
- FixedFPLiveRangeFor(code, MachineRepresentation::kFloat32);
- range->AddUseInterval(curr_position, curr_position.End(),
- allocation_zone());
- }
- for (int i = 0; i < config()->num_allocatable_simd128_registers();
- ++i) {
- int code = config()->GetAllocatableSimd128Code(i);
- TopLevelLiveRange* range =
- FixedFPLiveRangeFor(code, MachineRepresentation::kSimd128);
- range->AddUseInterval(curr_position, curr_position.End(),
- allocation_zone());
- }
- }
}
for (size_t i = 0; i < instr->InputCount(); i++) {
@@ -2644,15 +2589,9 @@ void LinearScanAllocator::AllocateRegisters() {
if (current != nullptr) AddToInactive(current);
}
} else {
- for (TopLevelLiveRange* current : data()->fixed_float_live_ranges()) {
- if (current != nullptr) AddToInactive(current);
- }
for (TopLevelLiveRange* current : data()->fixed_double_live_ranges()) {
if (current != nullptr) AddToInactive(current);
}
- for (TopLevelLiveRange* current : data()->fixed_simd128_live_ranges()) {
- if (current != nullptr) AddToInactive(current);
- }
}
while (!unhandled_live_ranges().empty()) {
@@ -2819,21 +2758,9 @@ void LinearScanAllocator::InactiveToActive(LiveRange* range) {
bool LinearScanAllocator::TryAllocateFreeReg(LiveRange* current) {
- MachineRepresentation rep = current->representation();
int num_regs = num_registers();
int num_codes = num_allocatable_registers();
const int* codes = allocatable_register_codes();
- if (!kSimpleFPAliasing) {
- if (rep == MachineRepresentation::kFloat32) {
- num_regs = data()->config()->num_float_registers();
- num_codes = data()->config()->num_allocatable_float_registers();
- codes = data()->config()->allocatable_float_codes();
- } else if (rep == MachineRepresentation::kSimd128) {
- num_regs = data()->config()->num_simd128_registers();
- num_codes = data()->config()->num_allocatable_simd128_registers();
- codes = data()->config()->allocatable_simd128_codes();
- }
- }
LifetimePosition free_until_pos[RegisterConfiguration::kMaxFPRegisters];
for (int i = 0; i < num_regs; i++) {
@@ -2842,21 +2769,9 @@ bool LinearScanAllocator::TryAllocateFreeReg(LiveRange* current) {
for (LiveRange* cur_active : active_live_ranges()) {
int cur_reg = cur_active->assigned_register();
- if (kSimpleFPAliasing || mode() == GENERAL_REGISTERS) {
- free_until_pos[cur_reg] = LifetimePosition::GapFromInstructionIndex(0);
- TRACE("Register %s is free until pos %d (1)\n", RegisterName(cur_reg),
- LifetimePosition::GapFromInstructionIndex(0).value());
- } else {
- int alias_base_index = -1;
- int aliases = data()->config()->GetAliases(
- cur_active->representation(), cur_reg, rep, &alias_base_index);
- DCHECK(aliases > 0 || (aliases == 0 && alias_base_index == -1));
- while (aliases--) {
- int aliased_reg = alias_base_index + aliases;
- free_until_pos[aliased_reg] =
- LifetimePosition::GapFromInstructionIndex(0);
- }
- }
+ free_until_pos[cur_reg] = LifetimePosition::GapFromInstructionIndex(0);
+ TRACE("Register %s is free until pos %d (1)\n", RegisterName(cur_reg),
+ LifetimePosition::GapFromInstructionIndex(0).value());
}
for (LiveRange* cur_inactive : inactive_live_ranges()) {
@@ -2865,21 +2780,9 @@ bool LinearScanAllocator::TryAllocateFreeReg(LiveRange* current) {
cur_inactive->FirstIntersection(current);
if (!next_intersection.IsValid()) continue;
int cur_reg = cur_inactive->assigned_register();
- if (kSimpleFPAliasing || mode() == GENERAL_REGISTERS) {
- free_until_pos[cur_reg] = Min(free_until_pos[cur_reg], next_intersection);
- TRACE("Register %s is free until pos %d (2)\n", RegisterName(cur_reg),
- Min(free_until_pos[cur_reg], next_intersection).value());
- } else {
- int alias_base_index = -1;
- int aliases = data()->config()->GetAliases(
- cur_inactive->representation(), cur_reg, rep, &alias_base_index);
- DCHECK(aliases > 0 || (aliases == 0 && alias_base_index == -1));
- while (aliases--) {
- int aliased_reg = alias_base_index + aliases;
- free_until_pos[aliased_reg] =
- Min(free_until_pos[aliased_reg], next_intersection);
- }
- }
+ free_until_pos[cur_reg] = Min(free_until_pos[cur_reg], next_intersection);
+ TRACE("Register %s is free until pos %d (2)\n", RegisterName(cur_reg),
+ Min(free_until_pos[cur_reg], next_intersection).value());
}
int hint_register;
@@ -2943,21 +2846,9 @@ void LinearScanAllocator::AllocateBlockedReg(LiveRange* current) {
return;
}
- MachineRepresentation rep = current->representation();
int num_regs = num_registers();
int num_codes = num_allocatable_registers();
const int* codes = allocatable_register_codes();
- if (!kSimpleFPAliasing) {
- if (rep == MachineRepresentation::kFloat32) {
- num_regs = data()->config()->num_float_registers();
- num_codes = data()->config()->num_allocatable_float_registers();
- codes = data()->config()->allocatable_float_codes();
- } else if (rep == MachineRepresentation::kSimd128) {
- num_regs = data()->config()->num_simd128_registers();
- num_codes = data()->config()->num_allocatable_simd128_registers();
- codes = data()->config()->allocatable_simd128_codes();
- }
- }
LifetimePosition use_pos[RegisterConfiguration::kMaxFPRegisters];
LifetimePosition block_pos[RegisterConfiguration::kMaxFPRegisters];
@@ -2969,38 +2860,16 @@ void LinearScanAllocator::AllocateBlockedReg(LiveRange* current) {
int cur_reg = range->assigned_register();
bool is_fixed_or_cant_spill =
range->TopLevel()->IsFixed() || !range->CanBeSpilled(current->Start());
- if (kSimpleFPAliasing || mode() == GENERAL_REGISTERS) {
- if (is_fixed_or_cant_spill) {
- block_pos[cur_reg] = use_pos[cur_reg] =
- LifetimePosition::GapFromInstructionIndex(0);
- } else {
- UsePosition* next_use =
- range->NextUsePositionRegisterIsBeneficial(current->Start());
- if (next_use == nullptr) {
- use_pos[cur_reg] = range->End();
- } else {
- use_pos[cur_reg] = next_use->pos();
- }
- }
+ if (is_fixed_or_cant_spill) {
+ block_pos[cur_reg] = use_pos[cur_reg] =
+ LifetimePosition::GapFromInstructionIndex(0);
} else {
- int alias_base_index = -1;
- int aliases = data()->config()->GetAliases(
- range->representation(), cur_reg, rep, &alias_base_index);
- DCHECK(aliases > 0 || (aliases == 0 && alias_base_index == -1));
- while (aliases--) {
- int aliased_reg = alias_base_index + aliases;
- if (is_fixed_or_cant_spill) {
- block_pos[aliased_reg] = use_pos[aliased_reg] =
- LifetimePosition::GapFromInstructionIndex(0);
- } else {
- UsePosition* next_use =
- range->NextUsePositionRegisterIsBeneficial(current->Start());
- if (next_use == nullptr) {
- use_pos[aliased_reg] = range->End();
- } else {
- use_pos[aliased_reg] = next_use->pos();
- }
- }
+ UsePosition* next_use =
+ range->NextUsePositionRegisterIsBeneficial(current->Start());
+ if (next_use == nullptr) {
+ use_pos[cur_reg] = range->End();
+ } else {
+ use_pos[cur_reg] = next_use->pos();
}
}
}
@@ -3011,29 +2880,11 @@ void LinearScanAllocator::AllocateBlockedReg(LiveRange* current) {
if (!next_intersection.IsValid()) continue;
int cur_reg = range->assigned_register();
bool is_fixed = range->TopLevel()->IsFixed();
- if (kSimpleFPAliasing || mode() == GENERAL_REGISTERS) {
- if (is_fixed) {
- block_pos[cur_reg] = Min(block_pos[cur_reg], next_intersection);
- use_pos[cur_reg] = Min(block_pos[cur_reg], use_pos[cur_reg]);
- } else {
- use_pos[cur_reg] = Min(use_pos[cur_reg], next_intersection);
- }
+ if (is_fixed) {
+ block_pos[cur_reg] = Min(block_pos[cur_reg], next_intersection);
+ use_pos[cur_reg] = Min(block_pos[cur_reg], use_pos[cur_reg]);
} else {
- int alias_base_index = -1;
- int aliases = data()->config()->GetAliases(
- range->representation(), cur_reg, rep, &alias_base_index);
- DCHECK(aliases > 0 || (aliases == 0 && alias_base_index == -1));
- while (aliases--) {
- int aliased_reg = alias_base_index + aliases;
- if (is_fixed) {
- block_pos[aliased_reg] =
- Min(block_pos[aliased_reg], next_intersection);
- use_pos[aliased_reg] =
- Min(block_pos[aliased_reg], use_pos[aliased_reg]);
- } else {
- use_pos[aliased_reg] = Min(use_pos[aliased_reg], next_intersection);
- }
- }
+ use_pos[cur_reg] = Min(use_pos[cur_reg], next_intersection);
}
}
@@ -3085,15 +2936,7 @@ void LinearScanAllocator::SplitAndSpillIntersecting(LiveRange* current) {
LifetimePosition split_pos = current->Start();
for (size_t i = 0; i < active_live_ranges().size(); ++i) {
LiveRange* range = active_live_ranges()[i];
- if (kSimpleFPAliasing || mode() == GENERAL_REGISTERS) {
- if (range->assigned_register() != reg) continue;
- } else {
- if (!data()->config()->AreAliases(current->representation(), reg,
- range->representation(),
- range->assigned_register())) {
- continue;
- }
- }
+ if (range->assigned_register() != reg) continue;
UsePosition* next_pos = range->NextRegisterPosition(current->Start());
LifetimePosition spill_pos = FindOptimalSpillingPos(range, split_pos);
@@ -3120,14 +2963,7 @@ void LinearScanAllocator::SplitAndSpillIntersecting(LiveRange* current) {
LiveRange* range = inactive_live_ranges()[i];
DCHECK(range->End() > current->Start());
if (range->TopLevel()->IsFixed()) continue;
- if (kSimpleFPAliasing || mode() == GENERAL_REGISTERS) {
- if (range->assigned_register() != reg) continue;
- } else {
- if (!data()->config()->AreAliases(current->representation(), reg,
- range->representation(),
- range->assigned_register()))
- continue;
- }
+ if (range->assigned_register() != reg) continue;
LifetimePosition next_intersection = range->FirstIntersection(current);
if (next_intersection.IsValid()) {
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