diff options
Diffstat (limited to 'gcc/range-op-ptr.cc')
| -rw-r--r-- | gcc/range-op-ptr.cc | 69 |
1 files changed, 67 insertions, 2 deletions
diff --git a/gcc/range-op-ptr.cc b/gcc/range-op-ptr.cc index dd51c2e..e0e21ad 100644 --- a/gcc/range-op-ptr.cc +++ b/gcc/range-op-ptr.cc @@ -218,6 +218,15 @@ range_operator::lhs_op1_relation (const prange &lhs ATTRIBUTE_UNUSED, return VREL_VARYING; } +relation_kind +range_operator::lhs_op1_relation (const prange &lhs ATTRIBUTE_UNUSED, + const prange &op1 ATTRIBUTE_UNUSED, + const irange &op2 ATTRIBUTE_UNUSED, + relation_kind rel ATTRIBUTE_UNUSED) const +{ + return VREL_VARYING; +} + void range_operator::update_bitmask (irange &, const prange &, @@ -293,6 +302,7 @@ class pointer_plus_operator : public range_operator using range_operator::update_bitmask; using range_operator::fold_range; using range_operator::op2_range; + using range_operator::lhs_op1_relation; public: virtual bool fold_range (prange &r, tree type, const prange &op1, @@ -302,6 +312,10 @@ public: const prange &lhs, const prange &op1, relation_trio = TRIO_VARYING) const final override; + virtual relation_kind lhs_op1_relation (const prange &lhs, + const prange &op1, + const irange &op2, + relation_kind) const final override; void update_bitmask (prange &r, const prange &lh, const irange &rh) const { update_known_bitmask (r, POINTER_PLUS_EXPR, lh, rh); } } op_pointer_plus; @@ -379,6 +393,51 @@ pointer_plus_operator::op2_range (irange &r, tree type, return true; } +// Return the relation between the LHS and OP1 based on the value of the +// operand being added. Pointer_plus is define to have a size_type for +// operand 2 which can be interpreted as negative, so always used SIGNED. +// Any overflow is considered UB and thus ignored. + +relation_kind +pointer_plus_operator::lhs_op1_relation (const prange &lhs, + const prange &op1, + const irange &op2, + relation_kind) const +{ + if (lhs.undefined_p () || op1.undefined_p () || op2.undefined_p ()) + return VREL_VARYING; + + unsigned prec = TYPE_PRECISION (op2.type ()); + + // LHS = OP1 + 0 indicates LHS == OP1. + if (op2.zero_p ()) + return VREL_EQ; + + tree val; + // Only deal with singletons for now. + if (TYPE_OVERFLOW_UNDEFINED (lhs.type ()) && op2.singleton_p (&val)) + { + // Always interpret VALUE as a signed value. Positive will increase + // the pointer value, and negative will decrease the poiinter value. + // It cannot be zero or the earlier zero_p () condition will catch it. + wide_int value = wi::to_wide (val); + + // Positive op2 means lhs > op1. + if (wi::gt_p (value, wi::zero (prec), SIGNED)) + return VREL_GT; + + // Negative op2 means lhs < op1. + if (wi::lt_p (value, wi::zero (prec), SIGNED)) + return VREL_LT; + } + + // If op2 does not contain 0, then LHS and OP1 can never be equal. + if (!range_includes_zero_p (op2)) + return VREL_NE; + + return VREL_VARYING; +} + bool operator_bitwise_or::fold_range (prange &r, tree type, const prange &op1, @@ -543,8 +602,14 @@ operator_cast::fold_range (prange &r, tree type, int_range<2> tmp = inner; tree pointer_uint_type = make_unsigned_type (TYPE_PRECISION (type)); range_cast (tmp, pointer_uint_type); - r.set (type, tmp.lower_bound (), tmp.upper_bound ()); - r.update_bitmask (tmp.get_bitmask ()); + // Casts may cause ranges to become UNDEFINED based on bitmasks. + if (tmp.undefined_p ()) + r.set_varying (type); + else + { + r.set (type, tmp.lower_bound (), tmp.upper_bound ()); + r.update_bitmask (tmp.get_bitmask ()); + } return true; } |