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Unified Diff: src/compiler/machine-operator-reducer.cc

Issue 426233002: Land the Fan (disabled) (Closed) Base URL: https://v8.googlecode.com/svn/branches/bleeding_edge
Patch Set: Review feedback, rebase and "git cl format" Created 6 years, 5 months ago
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Index: src/compiler/machine-operator-reducer.cc
diff --git a/src/compiler/machine-operator-reducer.cc b/src/compiler/machine-operator-reducer.cc
new file mode 100644
index 0000000000000000000000000000000000000000..4a4057646dde8bc0f60c8866207f52512ea06387
--- /dev/null
+++ b/src/compiler/machine-operator-reducer.cc
@@ -0,0 +1,343 @@
+// 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/compiler/common-node-cache.h"
+#include "src/compiler/generic-node-inl.h"
+#include "src/compiler/graph.h"
+#include "src/compiler/node-matchers.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+MachineOperatorReducer::MachineOperatorReducer(Graph* graph)
+ : graph_(graph),
+ cache_(new (graph->zone()) CommonNodeCache(graph->zone())),
+ common_(graph->zone()),
+ machine_(graph->zone()) {}
+
+
+MachineOperatorReducer::MachineOperatorReducer(Graph* graph,
+ CommonNodeCache* cache)
+ : graph_(graph),
+ cache_(cache),
+ common_(graph->zone()),
+ machine_(graph->zone()) {}
+
+
+Node* MachineOperatorReducer::Int32Constant(int32_t value) {
+ Node** loc = cache_->FindInt32Constant(value);
+ if (*loc == NULL) {
+ *loc = graph_->NewNode(common_.Int32Constant(value));
+ }
+ return *loc;
+}
+
+
+Node* MachineOperatorReducer::Float64Constant(volatile double value) {
+ Node** loc = cache_->FindFloat64Constant(value);
+ if (*loc == NULL) {
+ *loc = graph_->NewNode(common_.Float64Constant(value));
+ }
+ return *loc;
+}
+
+
+// Perform constant folding and strength reduction on machine operators.
+Reduction MachineOperatorReducer::Reduce(Node* node) {
+ switch (node->opcode()) {
+ 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
+ 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::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
+ graph_->ChangeOperator(node, 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
+ graph_->ChangeOperator(node, 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
+ graph_->ChangeOperator(node, 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
+ graph_->ChangeOperator(node, 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
+ graph_->ChangeOperator(node, 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;
+ }
+ // TODO(turbofan): strength-reduce and fold floating point operations.
+ default:
+ break;
+ }
+ return NoChange();
+}
+}
+}
+} // namespace v8::internal::compiler
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