vegorov@google.com
1ee5f51793
Previously it incorrectly computed OUT sets during the fix point iteration: did not propagate changed from IN to OUT. However just computing bitset representation of IN set was actually not enough because different values might be coming in from different predecessors. This algorithm inserts phis at merge points. R=fschneider@google.com BUG= Review URL: https://codereview.chromium.org//11505002 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@16109 260f80e4-7a28-3924-810f-c04153c831b5
108 lines
2.7 KiB
C++
108 lines
2.7 KiB
C++
// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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#include "vm/bit_vector.h"
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#include "vm/os.h"
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namespace dart {
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void BitVector::Iterator::Advance() {
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++bit_index_;
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// Skip zero words.
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if (current_word_ == 0) {
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do {
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++word_index_;
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if (Done()) return;
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current_word_ = target_->data_[word_index_];
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} while (current_word_ == 0);
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bit_index_ = word_index_ * kBitsPerWord;
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}
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// Skip zero bytes.
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while ((current_word_ & 0xff) == 0) {
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current_word_ >>= 8;
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bit_index_ += 8;
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}
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// Skip zero bits.
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while ((current_word_ & 0x1) == 0) {
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current_word_ >>= 1;
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++bit_index_;
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}
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current_word_ = current_word_ >> 1;
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}
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bool BitVector::Equals(const BitVector& other) const {
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if (length_ != other.length_) return false;
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intptr_t i = 0;
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for (; i < data_length_ - 1; i++) {
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if (data_[i] != other.data_[i]) return false;
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}
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if (i < data_length_) {
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// Don't compare bits beyond length_.
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uword mask =
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static_cast<uword>(-1) >> (kBitsPerWord - (length_ % kBitsPerWord));
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if ((data_[i] & mask) != (other.data_[i] & mask)) return false;
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}
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return true;
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}
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bool BitVector::AddAll(const BitVector* from) {
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ASSERT(data_length_ == from->data_length_);
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bool changed = false;
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for (intptr_t i = 0; i < data_length_; i++) {
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const uword before = data_[i];
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const uword after = data_[i] | from->data_[i];
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if (before != after) changed = true;
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data_[i] = after;
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}
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return changed;
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}
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bool BitVector::RemoveAll(const BitVector* from) {
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ASSERT(data_length_ == from->data_length_);
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bool changed = false;
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for (intptr_t i = 0; i < data_length_; i++) {
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const uword before = data_[i];
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const uword after = data_[i] & ~from->data_[i];
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if (before != after) changed = true;
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data_[i] = after;
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}
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return changed;
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}
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bool BitVector::KillAndAdd(BitVector* kill, BitVector* gen) {
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ASSERT(data_length_ == kill->data_length_);
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ASSERT(data_length_ == gen->data_length_);
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bool changed = false;
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for (intptr_t i = 0; i < data_length_; i++) {
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const uword before = data_[i];
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const uword after = data_[i] | (gen->data_[i] & ~kill->data_[i]);
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if (before != after) changed = true;
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data_[i] = after;
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}
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return changed;
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}
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void BitVector::Intersect(const BitVector& other) {
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ASSERT(other.length() == length());
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for (int i = 0; i < data_length_; i++) {
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data_[i] = data_[i] & other.data_[i];
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}
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}
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void BitVector::Print() const {
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OS::Print("[");
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for (intptr_t i = 0; i < length_; i++) {
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OS::Print(Contains(i) ? "1" : "0");
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}
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OS::Print("]");
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}
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} // namespace dart
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