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analyzer: fix sense in range::add_bound [PR94362]

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Mikael Morin spotted that I got the sense wrong when discarding
redundant constraints in
r12-6782-gc4b8f3730a80025192fdb485ad2535c165340e41.

Fixed as follows, which also moves the rejection of contradictory
constraints in range::add_bound to earlier, so that this code can
be self-tested.

gcc/analyzer/ChangeLog:
	PR analyzer/94362
	* constraint-manager.cc (range::add_bound): Fix tests for
	discarding redundant constraints.  Perform test for rejecting
	unsatisfiable constraints earlier so that they don't update
	the object on failure.
	(selftest::test_range): New.
	(selftest::test_constant_comparisons): Add test coverage for
	existing constraints becoming narrower until they are
	unsatisfiable.
	(selftest::run_constraint_manager_tests): Call test_range.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>
This commit is contained in:
David Malcolm 2022-01-25 11:35:24 -05:00
parent 192e4a9fa0
commit e966a508e0
1 changed files with 79 additions and 14 deletions
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93
gcc/analyzer/constraint-manager.cc
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@ -318,35 +318,42 @@ range::add_bound (bound b, enum bound_kind bound_kind)
if (m_lower_bound.m_constant)
{
m_lower_bound.ensure_closed (BK_LOWER);
if (!tree_int_cst_lt (b.m_constant,
m_lower_bound.m_constant))
if (tree_int_cst_le (b.m_constant,
m_lower_bound.m_constant))
return true;
}
if (m_upper_bound.m_constant)
{
m_upper_bound.ensure_closed (BK_UPPER);
/* Reject B <= V <= UPPER when B > UPPER. */
if (!tree_int_cst_le (b.m_constant,
m_upper_bound.m_constant))
return false;
}
m_lower_bound = b;
break;
case BK_UPPER:
/* Discard redundant bounds. */
if (m_upper_bound.m_constant)
{
m_upper_bound.ensure_closed (BK_UPPER);
if (tree_int_cst_le (b.m_constant,
m_upper_bound.m_constant))
if (!tree_int_cst_lt (b.m_constant,
m_upper_bound.m_constant))
return true;
}
if (m_lower_bound.m_constant)
{
m_lower_bound.ensure_closed (BK_LOWER);
/* Reject LOWER <= V <= B when LOWER > B. */
if (!tree_int_cst_le (m_lower_bound.m_constant,
b.m_constant))
return false;
}
m_upper_bound = b;
break;
}
if (m_lower_bound.m_constant
&& m_upper_bound.m_constant)
{
m_lower_bound.ensure_closed (BK_LOWER);
m_upper_bound.ensure_closed (BK_UPPER);
/* Reject LOWER <= V <= UPPER when LOWER > UPPER. */
if (!tree_int_cst_le (m_lower_bound.m_constant,
m_upper_bound.m_constant))
return false;
}
return true;
}
@ -3093,6 +3100,49 @@ namespace selftest {
These have to be written in terms of a region_model, since
the latter is responsible for managing svalue instances. */
/* Verify that range::add_bound works as expected. */
static void
test_range ()
{
tree int_0 = build_int_cst (integer_type_node, 0);
tree int_1 = build_int_cst (integer_type_node, 1);
tree int_2 = build_int_cst (integer_type_node, 2);
tree int_5 = build_int_cst (integer_type_node, 5);
{
range r;
ASSERT_FALSE (r.constrained_to_single_element ());
/* (r >= 1). */
ASSERT_TRUE (r.add_bound (GE_EXPR, int_1));
/* Redundant. */
ASSERT_TRUE (r.add_bound (GE_EXPR, int_0));
ASSERT_TRUE (r.add_bound (GT_EXPR, int_0));
ASSERT_FALSE (r.constrained_to_single_element ());
/* Contradiction. */
ASSERT_FALSE (r.add_bound (LT_EXPR, int_1));
/* (r < 5). */
ASSERT_TRUE (r.add_bound (LT_EXPR, int_5));
ASSERT_FALSE (r.constrained_to_single_element ());
/* Contradiction. */
ASSERT_FALSE (r.add_bound (GE_EXPR, int_5));
/* (r < 2). */
ASSERT_TRUE (r.add_bound (LT_EXPR, int_2));
ASSERT_TRUE (r.constrained_to_single_element ());
/* Redundant. */
ASSERT_TRUE (r.add_bound (LE_EXPR, int_1));
ASSERT_TRUE (r.constrained_to_single_element ());
}
}
/* Verify that setting and getting simple conditions within a region_model
work (thus exercising the underlying constraint_manager). */
@ -3700,6 +3750,20 @@ test_constant_comparisons ()
ADD_SAT_CONSTRAINT (model, int_3, LT_EXPR, a);
ADD_UNSAT_CONSTRAINT (model, a, LT_EXPR, int_4);
}
{
region_model model (&mgr);
ADD_SAT_CONSTRAINT (model, int_1, LT_EXPR, a);
ADD_SAT_CONSTRAINT (model, int_3, LT_EXPR, a);
ADD_SAT_CONSTRAINT (model, a, LT_EXPR, int_5);
ADD_UNSAT_CONSTRAINT (model, a, LT_EXPR, int_4);
}
{
region_model model (&mgr);
ADD_SAT_CONSTRAINT (model, int_1, LT_EXPR, a);
ADD_SAT_CONSTRAINT (model, a, LT_EXPR, int_5);
ADD_SAT_CONSTRAINT (model, int_3, LT_EXPR, a);
ADD_UNSAT_CONSTRAINT (model, a, LT_EXPR, int_4);
}
{
region_model model (&mgr);
ADD_SAT_CONSTRAINT (model, a, LT_EXPR, int_4);
@ -4323,6 +4387,7 @@ run_constraint_manager_tests (bool transitivity)
int saved_flag_analyzer_transitivity = flag_analyzer_transitivity;
flag_analyzer_transitivity = transitivity;
test_range ();
test_constraint_conditions ();
if (flag_analyzer_transitivity)
{