def _simplify(cls, invs, is_conj, use_reals):
assert invs, invs
st = time()
eqts, eqts_largecoefs, octs, mps, preposts, falseinvs = \
cls.classify(invs)
def mysorted(ps):
return sorted(ps, key=lambda p: len(Miscs.get_vars(p.inv)))
eqts = mysorted(eqts + eqts_largecoefs)
octs = mysorted(octs)
mps = mysorted(mps)
myinvs = eqts + falseinvs + preposts + octs + mps
myinvs_exprs = [inv.expr(use_reals) for inv in myinvs]
def _imply(js, i):
iexpr = myinvs_exprs[i]
# don't consider/remove equality
if iexpr.decl().kind() == z3.Z3_OP_EQ:
ret = False
else:
jexprs = [myinvs_exprs[j] for j in js]
ret = Z3._imply(jexprs, iexpr, is_conj)
# if ret:
# print '{} => {}'.format(jexprs, iexpr)
return ret
results = Miscs.simplify_idxs(list(range(len(myinvs))), _imply)
results = [myinvs[i] for i in results]
Miscs.show_removed('_simplify', len(invs), len(results), time() - st)
return results
def get_conj_preconds(self, loc, preconds, postcond_expr):
"""
preconds => post can be strengthened by removing some preconds
e.g., a&b => post is stronger than a&b&c => post
"""
assert all(isinstance(p, Inv) for p in preconds), preconds
assert z3.is_expr(postcond_expr), postcond_expr
if not preconds:
return []
preconds = sorted(preconds, key=lambda p: len(Miscs.get_vars(p.inv)))
preconds_exprs = [pc.expr(self.use_reals) for pc in preconds]
if not self.check(preconds_exprs, postcond_expr, loc):
return []
def _imply(js, _):
jexprs = [preconds_exprs[j] for j in js]
return self.check(jexprs, postcond_expr, loc)
results = Miscs.simplify_idxs(list(range(len(preconds))), _imply)
results = [preconds[i] for i in results]
return results
