js/src/jit/EdgeCaseAnalysis.cpp


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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sts=4 et sw=4 tw=99:
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "jit/EdgeCaseAnalysis.h"

#include "jit/MIR.h"
#include "jit/MIRGraph.h"

using namespace js;
using namespace js::jit;

EdgeCaseAnalysis::EdgeCaseAnalysis(MIRGenerator* mir, MIRGraph& graph)
  : mir(mir), graph(graph)
{
}

bool
EdgeCaseAnalysis::analyzeLate()
{
    // Renumber definitions for NeedNegativeZeroCheck under analyzeEdgeCasesBackward.
    uint32_t nextId = 0;

    for (ReversePostorderIterator block(graph.rpoBegin()); block != graph.rpoEnd(); block++) {
        for (MDefinitionIterator iter(*block); iter; iter++) {
            if (mir->shouldCancel("Analyze Late (first loop)"))
                return false;

            iter->setId(nextId++);
            iter->analyzeEdgeCasesForward();
        }
        block->lastIns()->setId(nextId++);
    }

    for (PostorderIterator block(graph.poBegin()); block != graph.poEnd(); block++) {
        for (MInstructionReverseIterator riter(block->rbegin()); riter != block->rend(); riter++) {
            if (mir->shouldCancel("Analyze Late (second loop)"))
                return false;

            riter->analyzeEdgeCasesBackward();
        }
    }

    return true;
}