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// Z3 4.1: /trace /z3opt:MBQI=true /proverOpt:OPTIMIZE_FOR_BV=true /z3opt:RELEVANCY=0
function {:inline} xor(a: bool, b: bool) returns (bool) { (!a && b) || (a && !b) }
procedure Incorrect_A(
{:visible} a: bool, {:hidden} b: bool)
returns ({:visible} ap: bool, {:hidden} bp: bool)
ensures xor(ap, bp) == xor(a, b);
{
ap := a;
bp := b;
}
procedure Incorrect_B(
{:hidden} a: bool, {:visible} b: bool)
returns ({:hidden} ap: bool, {:visible} bp: bool)
ensures xor(ap, bp) == xor(a, b);
{
ap := a;
bp := b;
}
procedure Incorrect_X(
{:hidden} a: bool, {:hidden} b: bool)
returns ({:hidden} ap: bool, {:hidden} bp: bool)
ensures xor(ap, bp) == xor(a, b);
{
ap := a;
bp := b;
}
procedure Correct_A(
{:visible} a: bool, {:hidden} b: bool)
returns ({:visible} ap: bool, {:hidden} bp: bool)
ensures xor(ap, bp) == xor(a, b);
{
havoc ap;
bp := xor(xor(ap, a), b);
}
procedure Correct_B(
{:hidden} a: bool, {:visible} b: bool)
returns ({:hidden} ap: bool, {:visible} bp: bool)
ensures xor(ap, bp) == xor(a, b);
{
havoc ap;
bp := xor(xor(ap, a), b);
}
procedure Correct_X(
{:hidden} a: bool, {:hidden} b: bool)
returns ({:hidden} ap: bool, {:hidden} bp: bool)
ensures xor(ap, bp) == xor(a, b);
{
havoc ap;
bp := xor(xor(ap, a), b);
}
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