public function testBranchedSimpleIf()
{
// if (a) { a = 0; } else { b = 0; } c = b;
$a = new Variable('a');
$b = new Variable('b');
$c = new Variable('c');
$inst1 = new BranchInstruction($a);
$inst2 = ArithmeticInstruction::newAssignNumberToVariableInstruction($a, 0);
$inst3 = ArithmeticInstruction::newAssignNumberToVariableInstruction($b, 0);
$inst4 = ArithmeticInstruction::newAssignVariableToVariableInstruction($c, $b);
$cfg = new ControlFlowGraph($inst1);
$cfg->connectIfNotConnected($inst1, GraphEdge::TYPE_ON_TRUE, $inst2);
$cfg->connectIfNotConnected($inst1, GraphEdge::TYPE_ON_FALSE, $inst3);
$cfg->connectIfNotConnected($inst2, GraphEdge::TYPE_UNCOND, $inst4);
$cfg->connectIfNotConnected($inst3, GraphEdge::TYPE_UNCOND, $inst4);
$n1 = $cfg->getNode($inst1);
$n2 = $cfg->getNode($inst2);
$n3 = $cfg->getNode($inst3);
$n4 = $cfg->getNode($inst4);
$constProp = new BranchedDummyConstPropagation($cfg);
$constProp->analyze();
// We cannot conclude anything from if(a).
$this->verifyInHas($n1, $a, null);
$this->verifyInHas($n1, $b, null);
$this->verifyInHas($n1, $c, null);
// Nothing is known on the true branch.
$this->verifyInHas($n2, $a, null);
$this->verifyInHas($n2, $b, null);
$this->verifyInHas($n2, $c, null);
// Verify that we have a = 0 on the false branch.
$this->verifyInHas($n3, $a, 0);
$this->verifyInHas($n3, $b, null);
$this->verifyInHas($n3, $c, null);
// After the merge we should still have a = 0.
$this->verifyInHas($n4, $a, 0);
}
