mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-10-11 04:15:43 +00:00
62 lines
2.1 KiB
C++
62 lines
2.1 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
|
|
*
|
|
* The contents of this file are subject to the Netscape Public
|
|
* License Version 1.1 (the "License"); you may not use this file
|
|
* except in compliance with the License. You may obtain a copy of
|
|
* the License at http://www.mozilla.org/NPL/
|
|
*
|
|
* Software distributed under the License is distributed on an "AS
|
|
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
|
|
* implied. See the License for the specific language governing
|
|
* rights and limitations under the License.
|
|
*
|
|
* The Original Code is mozilla.org code.
|
|
*
|
|
* The Initial Developer of the Original Code is Netscape
|
|
* Communications Corporation. Portions created by Netscape are
|
|
* Copyright (C) 1998 Netscape Communications Corporation. All
|
|
* Rights Reserved.
|
|
*
|
|
* Contributor(s):
|
|
*/
|
|
#include "PrimitiveOptimizer.h"
|
|
#include "ControlGraph.h"
|
|
|
|
//
|
|
// Quickly trim primitives whose results are not used from the graph.
|
|
// This is a quick-and-dirty implementation that misses some opportunities;
|
|
// for example, cycles of dead primitives are not detected.
|
|
//
|
|
void simpleTrimDeadPrimitives(ControlGraph &cg)
|
|
{
|
|
cg.dfsSearch();
|
|
ControlNode **dfsList = cg.dfsList;
|
|
ControlNode **pcn = dfsList + cg.nNodes;
|
|
|
|
while (pcn != dfsList) {
|
|
ControlNode &cn = **--pcn;
|
|
|
|
// Search the primitives backwards; remove any whose outputs are not used
|
|
// and which are not roots.
|
|
DoublyLinkedList<Primitive> &primitives = cn.getPrimitives();
|
|
DoublyLinkedList<Primitive>::iterator primIter = primitives.end();
|
|
while (!primitives.done(primIter)) {
|
|
Primitive &p = primitives.get(primIter);
|
|
primIter = primitives.retreat(primIter);
|
|
if (!p.isRoot() && !p.hasConsumers())
|
|
p.destroy();
|
|
}
|
|
|
|
// Search the phi nodes backwards; remove any whose outputs are not used.
|
|
DoublyLinkedList<PhiNode> &phiNodes = cn.getPhiNodes();
|
|
DoublyLinkedList<PhiNode>::iterator phiIter = phiNodes.end();
|
|
while (!phiNodes.done(phiIter)) {
|
|
PhiNode &n = phiNodes.get(phiIter);
|
|
phiIter = phiNodes.retreat(phiIter);
|
|
if (!n.hasConsumers())
|
|
n.remove();
|
|
}
|
|
}
|
|
}
|
|
|