// Copyright 2014 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/compiler/machine-operator-reducer.h"
#include "src/base/bits.h"
#include "src/compiler/generic-node-inl.h"
#include "src/compiler/graph.h"
#include "src/compiler/js-graph.h"
#include "src/compiler/node-matchers.h"
namespace v8 {
namespace internal {
namespace compiler {
MachineOperatorReducer::MachineOperatorReducer(JSGraph* jsgraph)
: jsgraph_(jsgraph) {}
MachineOperatorReducer::~MachineOperatorReducer() {}
Node* MachineOperatorReducer::Float32Constant(volatile float value) {
return graph()->NewNode(common()->Float32Constant(value));
}
Node* MachineOperatorReducer::Float64Constant(volatile double value) {
return jsgraph()->Float64Constant(value);
}
Node* MachineOperatorReducer::Int32Constant(int32_t value) {
return jsgraph()->Int32Constant(value);
}
Node* MachineOperatorReducer::Int64Constant(int64_t value) {
return graph()->NewNode(common()->Int64Constant(value));
}
// Perform constant folding and strength reduction on machine operators.
Reduction MachineOperatorReducer::Reduce(Node* node) {
switch (node->opcode()) {
case IrOpcode::kProjection:
return ReduceProjection(OpParameter<size_t>(node), node->InputAt(0));
case IrOpcode::kWord32And: {
Int32BinopMatcher m(node);
if (m.right().Is(0)) return Replace(m.right().node()); // x & 0 => 0
if (m.right().Is(-1)) return Replace(m.left().node()); // x & -1 => x
if (m.IsFoldable()) { // K & K => K
return ReplaceInt32(m.left().Value() & m.right().Value());
}
if (m.LeftEqualsRight()) return Replace(m.left().node()); // x & x => x
break;
}
case IrOpcode::kWord32Or: {
Int32BinopMatcher m(node);
if (m.right().Is(0)) return Replace(m.left().node()); // x | 0 => x
if (m.right().Is(-1)) return Replace(m.right().node()); // x | -1 => -1
if (m.IsFoldable()) { // K | K => K
return ReplaceInt32(m.left().Value() | m.right().Value());
}
if (m.LeftEqualsRight()) return Replace(m.left().node()); // x | x => x
if (m.left().IsWord32Shl() && m.right().IsWord32Shr()) {
Int32BinopMatcher mleft(m.left().node());
Int32BinopMatcher mright(m.right().node());
if (mleft.left().node() == mright.left().node()) {
// (x << y) | (x >> (32 - y)) => x ror y
if (mright.right().IsInt32Sub()) {
Int32BinopMatcher mrightright(mright.right().node());
if (mrightright.left().Is(32) &&
mrightright.right().node() == mleft.right().node()) {
node->set_op(machine()->Word32Ror());
node->ReplaceInput(0, mleft.left().node());
node->ReplaceInput(1, mleft.right().node());
return Changed(node);
}
}
// (x << K) | (x >> (32 - K)) => x ror K
if (mleft.right().IsInRange(0, 31) &&
mright.right().Is(32 - mleft.right().Value())) {
node->set_op(machine()->Word32Ror());
node->ReplaceInput(0, mleft.left().node());
node->ReplaceInput(1, mleft.right().node());
return Changed(node);
}
}
}
if (m.left().IsWord32Shr() && m.right().IsWord32Shl()) {
// (x >> (32 - y)) | (x << y) => x ror y
Int32BinopMatcher mleft(m.left().node());
Int32BinopMatcher mright(m.right().node());
if (mleft.left().node() == mright.left().node()) {
if (mleft.right().IsInt32Sub()) {
Int32BinopMatcher mleftright(mleft.right().node());
if (mleftright.left().Is(32) &&
mleftright.right().node() == mright.right().node()) {
node->set_op(machine()->Word32Ror());
node->ReplaceInput(0, mright.left().node());
node->ReplaceInput(1, mright.right().node());
return Changed(node);
}
}
// (x >> (32 - K)) | (x << K) => x ror K
if (mright.right().IsInRange(0, 31) &&
mleft.right().Is(32 - mright.right().Value())) {
node->set_op(machine()->Word32Ror());
node->ReplaceInput(0, mright.left().node());
node->ReplaceInput(1, mright.right().node());
return Changed(node);
}
}
}
break;
}
case IrOpcode::kWord32Xor: {
Int32BinopMatcher m(node);
if (m.right().Is(0)) return Replace(m.left().node()); // x ^ 0 => x
if (m.IsFoldable()) { // K ^ K => K
return ReplaceInt32(m.left().Value() ^ m.right().Value());
}
if (m.LeftEqualsRight()) return ReplaceInt32(0); // x ^ x => 0
break;
}
case IrOpcode::kWord32Shl: {
Int32BinopMatcher m(node);
if (m.right().Is(0)) return Replace(m.left().node()); // x << 0 => x
if (m.IsFoldable()) { // K << K => K
return ReplaceInt32(m.left().Value() << m.right().Value());
}
break;
}
case IrOpcode::kWord32Shr: {
Uint32BinopMatcher m(node);
if (m.right().Is(0)) return Replace(m.left().node()); // x >>> 0 => x
if (m.IsFoldable()) { // K >>> K => K
return ReplaceInt32(m.left().Value() >> m.right().Value());
}
break;
}
case IrOpcode::kWord32Sar: {
Int32BinopMatcher m(node);
if (m.right().Is(0)) return Replace(m.left().node()); // x >> 0 => x
if (m.IsFoldable()) { // K >> K => K
return ReplaceInt32(m.left().Value() >> m.right().Value());
}
break;
}
case IrOpcode::kWord32Ror: {
Int32BinopMatcher m(node);
if (m.right().Is(0)) return Replace(m.left().node()); // x ror 0 => x
if (m.IsFoldable()) { // K ror K => K
return ReplaceInt32(
base::bits::RotateRight32(m.left().Value(), m.right().Value()));
}
break;
}
case IrOpcode::kWord32Equal: {
Int32BinopMatcher m(node);
if (m.IsFoldable()) { // K == K => K
return ReplaceBool(m.left().Value() == m.right().Value());
}
if (m.left().IsInt32Sub() && m.right().Is(0)) { // x - y == 0 => x == y
Int32BinopMatcher msub(m.left().node());
node->ReplaceInput(0, msub.left().node());
node->ReplaceInput(1, msub.right().node());
return Changed(node);
}
// TODO(turbofan): fold HeapConstant, ExternalReference, pointer compares
if (m.LeftEqualsRight()) return ReplaceBool(true); // x == x => true
break;
}
case IrOpcode::kInt32Add: {
Int32BinopMatcher m(node);
if (m.right().Is(0)) return Replace(m.left().node()); // x + 0 => x
if (m.IsFoldable()) { // K + K => K
return ReplaceInt32(static_cast<uint32_t>(m.left().Value()) +
static_cast<uint32_t>(m.right().Value()));
}
break;
}
case IrOpcode::kInt32Sub: {
Int32BinopMatcher m(node);
if (m.right().Is(0)) return Replace(m.left().node()); // x - 0 => x
if (m.IsFoldable()) { // K - K => K
return ReplaceInt32(static_cast<uint32_t>(m.left().Value()) -
static_cast<uint32_t>(m.right().Value()));
}
if (m.LeftEqualsRight()) return ReplaceInt32(0); // x - x => 0
break;
}
case IrOpcode::kInt32Mul: {
Int32BinopMatcher m(node);
if (m.right().Is(0)) return Replace(m.right().node()); // x * 0 => 0
if (m.right().Is(1)) return Replace(m.left().node()); // x * 1 => x
if (m.IsFoldable()) { // K * K => K
return ReplaceInt32(m.left().Value() * m.right().Value());
}
if (m.right().Is(-1)) { // x * -1 => 0 - x
node->set_op(machine()->Int32Sub());
node->ReplaceInput(0, Int32Constant(0));
node->ReplaceInput(1, m.left().node());
return Changed(node);
}
if (m.right().IsPowerOf2()) { // x * 2^n => x << n
node->set_op(machine()->Word32Shl());
node->ReplaceInput(1, Int32Constant(WhichPowerOf2(m.right().Value())));
return Changed(node);
}
break;
}
case IrOpcode::kInt32Div: {
Int32BinopMatcher m(node);
if (m.right().Is(1)) return Replace(m.left().node()); // x / 1 => x
// TODO(turbofan): if (m.left().Is(0))
// TODO(turbofan): if (m.right().IsPowerOf2())
// TODO(turbofan): if (m.right().Is(0))
// TODO(turbofan): if (m.LeftEqualsRight())
if (m.IsFoldable() && !m.right().Is(0)) { // K / K => K
if (m.right().Is(-1)) return ReplaceInt32(-m.left().Value());
return ReplaceInt32(m.left().Value() / m.right().Value());
}
if (m.right().Is(-1)) { // x / -1 => 0 - x
node->set_op(machine()->Int32Sub());
node->ReplaceInput(0, Int32Constant(0));
node->ReplaceInput(1, m.left().node());
return Changed(node);
}
break;
}
case IrOpcode::kInt32UDiv: {
Uint32BinopMatcher m(node);
if (m.right().Is(1)) return Replace(m.left().node()); // x / 1 => x
// TODO(turbofan): if (m.left().Is(0))
// TODO(turbofan): if (m.right().Is(0))
// TODO(turbofan): if (m.LeftEqualsRight())
if (m.IsFoldable() && !m.right().Is(0)) { // K / K => K
return ReplaceInt32(m.left().Value() / m.right().Value());
}
if (m.right().IsPowerOf2()) { // x / 2^n => x >> n
node->set_op(machine()->Word32Shr());
node->ReplaceInput(1, Int32Constant(WhichPowerOf2(m.right().Value())));
return Changed(node);
}
break;
}
case IrOpcode::kInt32Mod: {
Int32BinopMatcher m(node);
if (m.right().Is(1)) return ReplaceInt32(0); // x % 1 => 0
if (m.right().Is(-1)) return ReplaceInt32(0); // x % -1 => 0
// TODO(turbofan): if (m.left().Is(0))
// TODO(turbofan): if (m.right().IsPowerOf2())
// TODO(turbofan): if (m.right().Is(0))
// TODO(turbofan): if (m.LeftEqualsRight())
if (m.IsFoldable() && !m.right().Is(0)) { // K % K => K
return ReplaceInt32(m.left().Value() % m.right().Value());
}
break;
}
case IrOpcode::kInt32UMod: {
Uint32BinopMatcher m(node);
if (m.right().Is(1)) return ReplaceInt32(0); // x % 1 => 0
// TODO(turbofan): if (m.left().Is(0))
// TODO(turbofan): if (m.right().Is(0))
// TODO(turbofan): if (m.LeftEqualsRight())
if (m.IsFoldable() && !m.right().Is(0)) { // K % K => K
return ReplaceInt32(m.left().Value() % m.right().Value());
}
if (m.right().IsPowerOf2()) { // x % 2^n => x & 2^n-1
node->set_op(machine()->Word32And());
node->ReplaceInput(1, Int32Constant(m.right().Value() - 1));
return Changed(node);
}
break;
}
case IrOpcode::kInt32LessThan: {
Int32BinopMatcher m(node);
if (m.IsFoldable()) { // K < K => K
return ReplaceBool(m.left().Value() < m.right().Value());
}
if (m.left().IsInt32Sub() && m.right().Is(0)) { // x - y < 0 => x < y
Int32BinopMatcher msub(m.left().node());
node->ReplaceInput(0, msub.left().node());
node->ReplaceInput(1, msub.right().node());
return Changed(node);
}
if (m.left().Is(0) && m.right().IsInt32Sub()) { // 0 < x - y => y < x
Int32BinopMatcher msub(m.right().node());
node->ReplaceInput(0, msub.right().node());
node->ReplaceInput(1, msub.left().node());
return Changed(node);
}
if (m.LeftEqualsRight()) return ReplaceBool(false); // x < x => false
break;
}
case IrOpcode::kInt32LessThanOrEqual: {
Int32BinopMatcher m(node);
if (m.IsFoldable()) { // K <= K => K
return ReplaceBool(m.left().Value() <= m.right().Value());
}
if (m.left().IsInt32Sub() && m.right().Is(0)) { // x - y <= 0 => x <= y
Int32BinopMatcher msub(m.left().node());
node->ReplaceInput(0, msub.left().node());
node->ReplaceInput(1, msub.right().node());
return Changed(node);
}
if (m.left().Is(0) && m.right().IsInt32Sub()) { // 0 <= x - y => y <= x
Int32BinopMatcher msub(m.right().node());
node->ReplaceInput(0, msub.right().node());
node->ReplaceInput(1, msub.left().node());
return Changed(node);
}
if (m.LeftEqualsRight()) return ReplaceBool(true); // x <= x => true
break;
}
case IrOpcode::kUint32LessThan: {
Uint32BinopMatcher m(node);
if (m.left().Is(kMaxUInt32)) return ReplaceBool(false); // M < x => false
if (m.right().Is(0)) return ReplaceBool(false); // x < 0 => false
if (m.IsFoldable()) { // K < K => K
return ReplaceBool(m.left().Value() < m.right().Value());
}
if (m.LeftEqualsRight()) return ReplaceBool(false); // x < x => false
break;
}
case IrOpcode::kUint32LessThanOrEqual: {
Uint32BinopMatcher m(node);
if (m.left().Is(0)) return ReplaceBool(true); // 0 <= x => true
if (m.right().Is(kMaxUInt32)) return ReplaceBool(true); // x <= M => true
if (m.IsFoldable()) { // K <= K => K
return ReplaceBool(m.left().Value() <= m.right().Value());
}
if (m.LeftEqualsRight()) return ReplaceBool(true); // x <= x => true
break;
}
case IrOpcode::kFloat64Add: {
Float64BinopMatcher m(node);
if (m.IsFoldable()) { // K + K => K
return ReplaceFloat64(m.left().Value() + m.right().Value());
}
break;
}
case IrOpcode::kFloat64Sub: {
Float64BinopMatcher m(node);
if (m.IsFoldable()) { // K - K => K
return ReplaceFloat64(m.left().Value() - m.right().Value());
}
break;
}
case IrOpcode::kFloat64Mul: {
Float64BinopMatcher m(node);
if (m.right().Is(1)) return Replace(m.left().node()); // x * 1.0 => x
if (m.right().IsNaN()) { // x * NaN => NaN
return Replace(m.right().node());
}
if (m.IsFoldable()) { // K * K => K
return ReplaceFloat64(m.left().Value() * m.right().Value());
}
break;
}
case IrOpcode::kFloat64Div: {
Float64BinopMatcher m(node);
if (m.right().Is(1)) return Replace(m.left().node()); // x / 1.0 => x
if (m.right().IsNaN()) { // x / NaN => NaN
return Replace(m.right().node());
}
if (m.left().IsNaN()) { // NaN / x => NaN
return Replace(m.left().node());
}
if (m.IsFoldable()) { // K / K => K
return ReplaceFloat64(m.left().Value() / m.right().Value());
}
break;
}
case IrOpcode::kFloat64Mod: {
Float64BinopMatcher m(node);
if (m.right().IsNaN()) { // x % NaN => NaN
return Replace(m.right().node());
}
if (m.left().IsNaN()) { // NaN % x => NaN
return Replace(m.left().node());
}
if (m.IsFoldable()) { // K % K => K
return ReplaceFloat64(modulo(m.left().Value(), m.right().Value()));
}
break;
}
case IrOpcode::kChangeFloat32ToFloat64: {
Float32Matcher m(node->InputAt(0));
if (m.HasValue()) return ReplaceFloat64(m.Value());
break;
}
case IrOpcode::kChangeFloat64ToInt32: {
Float64Matcher m(node->InputAt(0));
if (m.HasValue()) return ReplaceInt32(FastD2I(m.Value()));
if (m.IsChangeInt32ToFloat64()) return Replace(m.node()->InputAt(0));
break;
}
case IrOpcode::kChangeFloat64ToUint32: {
Float64Matcher m(node->InputAt(0));
if (m.HasValue()) return ReplaceInt32(FastD2UI(m.Value()));
if (m.IsChangeUint32ToFloat64()) return Replace(m.node()->InputAt(0));
break;
}
case IrOpcode::kChangeInt32ToFloat64: {
Int32Matcher m(node->InputAt(0));
if (m.HasValue()) return ReplaceFloat64(FastI2D(m.Value()));
break;
}
case IrOpcode::kChangeInt32ToInt64: {
Int32Matcher m(node->InputAt(0));
if (m.HasValue()) return ReplaceInt64(m.Value());
break;
}
case IrOpcode::kChangeUint32ToFloat64: {
Uint32Matcher m(node->InputAt(0));
if (m.HasValue()) return ReplaceFloat64(FastUI2D(m.Value()));
break;
}
case IrOpcode::kChangeUint32ToUint64: {
Uint32Matcher m(node->InputAt(0));
if (m.HasValue()) return ReplaceInt64(static_cast<uint64_t>(m.Value()));
break;
}
case IrOpcode::kTruncateFloat64ToInt32: {
Float64Matcher m(node->InputAt(0));
if (m.HasValue()) return ReplaceInt32(DoubleToInt32(m.Value()));
if (m.IsChangeInt32ToFloat64()) return Replace(m.node()->InputAt(0));
break;
}
case IrOpcode::kTruncateInt64ToInt32: {
Int64Matcher m(node->InputAt(0));
if (m.HasValue()) return ReplaceInt32(static_cast<int32_t>(m.Value()));
if (m.IsChangeInt32ToInt64()) return Replace(m.node()->InputAt(0));
break;
}
case IrOpcode::kTruncateFloat64ToFloat32: {
Float64Matcher m(node->InputAt(0));
if (m.HasValue()) return ReplaceFloat32(DoubleToFloat32(m.Value()));
if (m.IsChangeFloat32ToFloat64()) return Replace(m.node()->InputAt(0));
break;
}
default:
break;
}
return NoChange();
}
Reduction MachineOperatorReducer::ReduceProjection(size_t index, Node* node) {
switch (node->opcode()) {
case IrOpcode::kInt32AddWithOverflow: {
DCHECK(index == 0 || index == 1);
Int32BinopMatcher m(node);
if (m.IsFoldable()) {
int32_t val;
bool ovf = base::bits::SignedAddOverflow32(m.left().Value(),
m.right().Value(), &val);
return ReplaceInt32((index == 0) ? val : ovf);
}
if (m.right().Is(0)) {
return (index == 0) ? Replace(m.left().node()) : ReplaceInt32(0);
}
break;
}
case IrOpcode::kInt32SubWithOverflow: {
DCHECK(index == 0 || index == 1);
Int32BinopMatcher m(node);
if (m.IsFoldable()) {
int32_t val;
bool ovf = base::bits::SignedSubOverflow32(m.left().Value(),
m.right().Value(), &val);
return ReplaceInt32((index == 0) ? val : ovf);
}
if (m.right().Is(0)) {
return (index == 0) ? Replace(m.left().node()) : ReplaceInt32(0);
}
break;
}
default:
break;
}
return NoChange();
}
CommonOperatorBuilder* MachineOperatorReducer::common() const {
return jsgraph()->common();
}
MachineOperatorBuilder* MachineOperatorReducer::machine() const {
return jsgraph()->machine();
}
Graph* MachineOperatorReducer::graph() const { return jsgraph()->graph(); }
} // namespace compiler
} // namespace internal
} // namespace v8