Improve redundant load elimination

runtime/vm/bit_vector.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/bit_vector.h"
 
 #include "vm/os.h"
 
 namespace dart {
 
@@ skipping 44 matching lines @@
   for (intptr_t i = 0; i < data_length_; i++) {
     const uword before = data_[i];
     const uword after = data_[i] | from->data_[i];
     if (before != after) changed = true;
     data_[i] = after;
   }
   return changed;
 }
 
 
+bool BitVector::RemoveAll(const BitVector* from) {

[Florian Schneider, 2012/12/13 13:21:06]

Please also add a test case to bit_vector_test.cc.

[Vyacheslav Egorov (Google), 2012/12/13 14:02:59]

Done.

+  ASSERT(data_length_ == from->data_length_);
+  bool changed = false;
+  for (intptr_t i = 0; i < data_length_; i++) {
+    const uword before = data_[i];
+    const uword after = data_[i] & ~from->data_[i];
+    if (before != after) changed = true;
+    data_[i] = after;
+  }
+  return changed;
+}
+
 bool BitVector::KillAndAdd(BitVector* kill, BitVector* gen) {
   ASSERT(data_length_ == kill->data_length_);
   ASSERT(data_length_ == gen->data_length_);
   bool changed = false;
   for (intptr_t i = 0; i < data_length_; i++) {
     const uword before = data_[i];
     const uword after = data_[i] | (gen->data_[i] & ~kill->data_[i]);
     if (before != after) changed = true;
     data_[i] = after;
   }
@@ skipping 11 matching lines @@
 
 void BitVector::Print() const {
   OS::Print("[");
   for (intptr_t i = 0; i < length_; i++) {
     OS::Print(Contains(i) ? "1" : "0");
   }
   OS::Print("]");
 }
 
 }  // namespace dart