PHPCfg\Visitor\Simplifier::removeTrivialPhi PHP Method

    private function removeTrivialPhi(Block $block)
    {
        $toReplace = new \SplObjectStorage();
        $replaced = new \SplObjectStorage();
        $toReplace->attach($block);
        while ($toReplace->count() > 0) {
            foreach ($toReplace as $block) {
                $toReplace->detach($block);
                $replaced->attach($block);
                foreach ($block->phi as $key => $phi) {
                    if ($this->tryRemoveTrivialPhi($phi, $block)) {
                        unset($block->phi[$key]);
                    }
                }
                foreach ($block->children as $child) {
                    foreach ($child->getSubBlocks() as $name) {
                        $subBlocks = $child->{$name};
                        if (!is_array($child->{$name})) {
                            if ($child->{$name} === null) {
                                continue;
                            }
                            $subBlocks = [$subBlocks];
                        }
                        foreach ($subBlocks as $subBlock) {
                            if (!$replaced->contains($subBlock)) {
                                $toReplace->attach($subBlock);
                            }
                        }
                    }
                }
            }
        }
        while ($this->trivialPhiCandidates->count() > 0) {
            foreach ($this->trivialPhiCandidates as $phi) {
                $block = $this->trivialPhiCandidates[$phi];
                $this->trivialPhiCandidates->detach($phi);
                if ($this->tryRemoveTrivialPhi($phi, $block)) {
                    $key = array_search($phi, $block->phi, true);
                    if ($key !== false) {
                        unset($block->phi[$key]);
                    }
                }
            }
        }
    }