diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/range-op.cc | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/gcc/range-op.cc b/gcc/range-op.cc index a7698f2..ec4816d 100644 --- a/gcc/range-op.cc +++ b/gcc/range-op.cc @@ -1279,6 +1279,11 @@ public: const wide_int &lh_ub, const wide_int &rh_lb, const wide_int &rh_ub) const; + virtual bool op1_op2_relation_effect (irange &lhs_range, + tree type, + const irange &op1_range, + const irange &op2_range, + relation_kind rel) const; } op_minus; void @@ -1293,6 +1298,45 @@ operator_minus::wi_fold (irange &r, tree type, value_range_with_overflow (r, type, new_lb, new_ub, ov_lb, ov_ub); } +// Check to see if the relation REL between OP1 and OP2 has any effect on the +// LHS of the epxression. If so, apply it to LHS_RANGE. + +bool +operator_minus::op1_op2_relation_effect (irange &lhs_range, tree type, + const irange &op1_range ATTRIBUTE_UNUSED, + const irange &op2_range ATTRIBUTE_UNUSED, + relation_kind rel) const +{ + if (rel == VREL_NONE) + return false; + + int_range<2> rel_range; + unsigned prec = TYPE_PRECISION (type); + signop sgn = TYPE_SIGN (type); + + switch (rel) + { + // op1 > op2, op1 - op2 can be restricted to [1, max] + case GT_EXPR: + rel_range = int_range<2> (type, wi::one (prec), + wi::max_value (prec, sgn)); + break; + // op1 >= op2, op1 - op2 can be restricted to [0, max] + case GE_EXPR: + rel_range = int_range<2> (type, wi::zero (prec), + wi::max_value (prec, sgn)); + break; + // op1 == op2, op1 - op2 can be restricted to [0, 0] + case EQ_EXPR: + rel_range = int_range<2> (type, wi::zero (prec), wi::zero (prec)); + break; + default: + return false; + } + lhs_range.intersect (rel_range); + return true; +} + bool operator_minus::op1_range (irange &r, tree type, const irange &lhs, |