/// maximalIntersectWith - Return the range that results from the intersection
/// of this range with another range. The resultant range is guaranteed to
/// include all elements contained in both input ranges, and to have the
/// smallest possible set size that does so. Because there may be two
/// intersections with the same set size, A.maximalIntersectWith(B) might not
/// be equal to B.maximalIntersect(A).
ConstantRange ConstantRange::maximalIntersectWith(const ConstantRange &CR) const {
assert(getBitWidth() == CR.getBitWidth() &&
"ConstantRange types don't agree!");
// Handle common cases.
if ( isEmptySet() || CR.isFullSet()) return *this;
if (CR.isEmptySet() || isFullSet()) return CR;
if (!isWrappedSet() && CR.isWrappedSet())
return CR.maximalIntersectWith(*this);
if (!isWrappedSet() && !CR.isWrappedSet()) {
if (Lower.ult(CR.Lower)) {
if (Upper.ule(CR.Lower))
return ConstantRange(getBitWidth(), false);
if (Upper.ult(CR.Upper))
return ConstantRange(CR.Lower, Upper);
return CR;
} else {
if (Upper.ult(CR.Upper))
return *this;
if (Lower.ult(CR.Upper))
return ConstantRange(Lower, CR.Upper);
return ConstantRange(getBitWidth(), false);
}
}
if (isWrappedSet() && !CR.isWrappedSet()) {
if (CR.Lower.ult(Upper)) {
if (CR.Upper.ult(Upper))
return CR;
if (CR.Upper.ult(Lower))
return ConstantRange(CR.Lower, Upper);
if (getSetSize().ult(CR.getSetSize()))
return *this;
else
return CR;
} else if (CR.Lower.ult(Lower)) {
if (CR.Upper.ule(Lower))
return ConstantRange(getBitWidth(), false);
return ConstantRange(Lower, CR.Upper);
}
return CR;
}
if (CR.Upper.ult(Upper)) {
if (CR.Lower.ult(Upper)) {
if (getSetSize().ult(CR.getSetSize()))
return *this;
else
return CR;
}
if (CR.Lower.ult(Lower))
return ConstantRange(Lower, CR.Upper);
return CR;
} else if (CR.Upper.ult(Lower)) {
if (CR.Lower.ult(Lower))
return *this;
return ConstantRange(CR.Lower, Upper);
}
if (getSetSize().ult(CR.getSetSize()))
return *this;
else
return CR;
}
