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range-ops: (nonzero | X) is nonzero

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For bitwise or, nonzero|X is always nonzero.  Make sure we don't drop to
varying in this case.

gcc/ChangeLog:

	* range-op.cc (operator_bitwise_or::wi_fold): Make sure
	nonzero|X is nonzero.
	(range_op_bitwise_and_tests): Add tests for above.
This commit is contained in:
Aldy Hernandez 2021-06-14 12:51:48 +02:00
parent 913b13fcb1
commit 4602714382
1 changed files with 26 additions and 5 deletions
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31
gcc/range-op.cc
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@ -2534,11 +2534,20 @@ operator_bitwise_or::wi_fold (irange &r, tree type,
new_lb = wi::max (new_lb, lh_lb, sign);
if (wi::lt_p (rh_ub, 0, sign))
new_lb = wi::max (new_lb, rh_lb, sign);
// If the limits got swapped around, return varying.
if (wi::gt_p (new_lb, new_ub,sign))
r.set_varying (type);
else
value_range_with_overflow (r, type, new_lb, new_ub);
// If the limits got swapped around, return a conservative range.
if (wi::gt_p (new_lb, new_ub, sign))
{
// Make sure that nonzero|X is nonzero.
if (wi::gt_p (lh_lb, 0, sign)
|| wi::gt_p (rh_lb, 0, sign)
|| wi::lt_p (lh_ub, 0, sign)
|| wi::lt_p (rh_ub, 0, sign))
r.set_nonzero (type);
else
r.set_varying (type);
return;
}
value_range_with_overflow (r, type, new_lb, new_ub);
}
bool
@ -3744,6 +3753,18 @@ range_op_bitwise_and_tests ()
i1 = int_range<1> (integer_type_node);
op_bitwise_and.op1_range (res, integer_type_node, i1, i2);
ASSERT_TRUE (res == int_range<1> (integer_type_node));
// (NONZERO | X) is nonzero.
i1.set_nonzero (integer_type_node);
i2.set_varying (integer_type_node);
op_bitwise_or.fold_range (res, integer_type_node, i1, i2);
ASSERT_TRUE (res.nonzero_p ());
// (NEGATIVE | X) is nonzero.
i1 = int_range<1> (INT (-5), INT (-3));
i2.set_varying (integer_type_node);
op_bitwise_or.fold_range (res, integer_type_node, i1, i2);
ASSERT_FALSE (res.contains_p (INT (0)));
}
void