v8/src/hydrogen-mark-deoptimize.cc
verwaest@chromium.org 169f5a9d7b Never hchange nan-hole to hole or hole to nan-hole.
Only allow changing hole to nan if all uses allow undefined as nan.

R=danno@chromium.org

Review URL: https://chromiumcodereview.appspot.com/22152003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16183 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-08-14 08:54:27 +00:00

85 lines
3.2 KiB
C++

// Copyright 2013 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "hydrogen-mark-deoptimize.h"
namespace v8 {
namespace internal {
void HMarkDeoptimizeOnUndefinedPhase::Run() {
const ZoneList<HPhi*>* phi_list = graph()->phi_list();
for (int i = 0; i < phi_list->length(); i++) {
HPhi* phi = phi_list->at(i);
if (phi->CheckFlag(HValue::kAllowUndefinedAsNaN) &&
!phi->CheckUsesForFlag(HValue::kAllowUndefinedAsNaN)) {
ProcessPhi(phi);
}
}
}
void HMarkDeoptimizeOnUndefinedPhase::ProcessPhi(HPhi* phi) {
ASSERT(phi->CheckFlag(HValue::kAllowUndefinedAsNaN));
ASSERT(worklist_.is_empty());
// Push the phi onto the worklist
phi->ClearFlag(HValue::kAllowUndefinedAsNaN);
worklist_.Add(phi, zone());
// Process all phis that can reach this phi
while (!worklist_.is_empty()) {
phi = worklist_.RemoveLast();
for (int i = phi->OperandCount() - 1; i >= 0; --i) {
HValue* input = phi->OperandAt(i);
if (input->IsPhi() && input->CheckFlag(HValue::kAllowUndefinedAsNaN)) {
input->ClearFlag(HValue::kAllowUndefinedAsNaN);
worklist_.Add(HPhi::cast(input), zone());
}
}
}
}
void HComputeChangeUndefinedToNaN::Run() {
const ZoneList<HBasicBlock*>* blocks(graph()->blocks());
for (int i = 0; i < blocks->length(); ++i) {
const HBasicBlock* block(blocks->at(i));
for (HInstruction* current = block->first(); current != NULL; ) {
HInstruction* next = current->next();
if (current->IsChange()) {
if (HChange::cast(current)->can_convert_undefined_to_nan()) {
current->SetFlag(HValue::kAllowUndefinedAsNaN);
}
}
current = next;
}
}
}
} } // namespace v8::internal