unsigned prec = TYPE_PRECISION (type);
signop sgn = TYPE_SIGN (type);
- switch (rel)
+ // == and != produce [0,0] and ~[0,0] regardless of wrapping.
+ if (rel == EQ_EXPR)
+ rel_range = int_range<2> (type, wi::zero (prec), wi::zero (prec));
+ else if (rel == NE_EXPR)
+ rel_range = int_range<2> (type, wi::zero (prec), wi::zero (prec),
+ VR_ANTI_RANGE);
+ else if (TYPE_OVERFLOW_WRAPS (type))
{
- // 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;
+ switch (rel)
+ {
+ // For wrapping signed values and unsigned, if op1 > op2 or
+ // op1 < op2, then op1 - op2 can be restricted to ~[0, 0].
+ case GT_EXPR:
+ case LT_EXPR:
+ rel_range = int_range<2> (type, wi::zero (prec), wi::zero (prec),
+ VR_ANTI_RANGE);
+ break;
+ default:
+ return false;
+ }
+ }
+ else
+ {
+ switch (rel)
+ {
+ // op1 > op2, op1 - op2 can be restricted to [1, +INF]
+ 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, +INF]
+ 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 [-INF, -1]
+ case LT_EXPR:
+ rel_range = int_range<2> (type, wi::min_value (prec, sgn),
+ wi::minus_one (prec));
+ break;
+ // op1 <= op2, op1 - op2 can be restricted to [-INF, 0]
+ case LE_EXPR:
+ rel_range = int_range<2> (type, wi::min_value (prec, sgn),
+ wi::zero (prec));
+ break;
+ default:
+ return false;
+ }
}
lhs_range.intersect (rel_range);
return true;