public function testSimpleLoop()
{
// a = 0; do { a = a + 1 } while (b); c = a;
$a = new Variable('a');
$b = new Variable('b');
$c = new Variable('c');
$inst1 = ArithmeticInstruction::newAssignNumberToVariableInstruction($a, 0);
$inst2 = new ArithmeticInstruction($a, $a, '+', new Number(1));
$inst3 = new BranchInstruction($b);
$inst4 = ArithmeticInstruction::newAssignVariableToVariableInstruction($c, $a);
$cfg = new ControlFlowGraph($inst1);
$cfg->connectIfNotConnected($inst1, GraphEdge::TYPE_UNCOND, $inst2);
$cfg->connectIfNotConnected($inst2, GraphEdge::TYPE_UNCOND, $inst3);
$cfg->connectifNotConnected($inst3, GraphEdge::TYPE_ON_TRUE, $inst2);
$cfg->connectIfNotConnected($inst3, GraphEdge::TYPE_ON_FALSE, $inst4);
$n1 = $cfg->getNode($inst1);
$n2 = $cfg->getNode($inst2);
$n3 = $cfg->getNode($inst3);
$n4 = $cfg->getNode($inst4);
$constProp = new DummyConstPropagation($cfg);
// This will also show that the framework terminates properly.
$constProp->analyze();
// a = 0 is the only thing we know.
$this->verifyInHas($n1, $a, null);
$this->verifyInHas($n1, $b, null);
$this->verifyInHas($n1, $c, null);
$this->verifyOutHas($n1, $a, 0);
$this->verifyOutHas($n1, $b, null);
$this->verifyOutHas($n1, $c, null);
// Nothing is provable in this program, so confirm that we haven't
// erroneously "proven" something.
$this->verifyInHas($n2, $a, null);
$this->verifyInHas($n2, $b, null);
$this->verifyInHas($n2, $c, null);
$this->verifyOutHas($n2, $a, null);
$this->verifyOutHas($n2, $b, null);
$this->verifyOutHas($n2, $c, null);
$this->verifyInHas($n3, $a, null);
$this->verifyInHas($n3, $b, null);
$this->verifyInHas($n3, $c, null);
$this->verifyOutHas($n3, $a, null);
$this->verifyOutHas($n3, $b, null);
$this->verifyOutHas($n3, $c, null);
$this->verifyInHas($n4, $a, null);
$this->verifyInHas($n4, $b, null);
$this->verifyInHas($n4, $c, null);
$this->verifyOutHas($n4, $a, null);
$this->verifyOutHas($n4, $b, null);
$this->verifyOutHas($n4, $c, null);
}
