Interval.cpp
#include "Interval.h"
#include "IREquality.h"
#include "IRMatch.h"
#include "IROperator.h"
namespace Halide {
namespace Internal {
namespace {
IRMatcher::Wild<0> x;
IRMatcher::Wild<1> y;
IRMatcher::WildConst<0> c0;
IRMatcher::WildConst<1> c1;
Expr make_max_helper(const Expr &a, const Expr &b) {
auto rewrite = IRMatcher::rewriter(IRMatcher::max(a, b), a.type());
Expr pos_inf = Interval::pos_inf();
Expr neg_inf = Interval::neg_inf();
if (rewrite(max(x, x), x) ||
rewrite(max(x, pos_inf), pos_inf) ||
rewrite(max(pos_inf, x), pos_inf) ||
rewrite(max(x, neg_inf), x) ||
rewrite(max(neg_inf, x), x) ||
rewrite(max(c0, c1), fold(max(c0, c1))) ||
rewrite(max(c0, x), max(x, c0)) ||
rewrite(max(max(x, c0), c1), max(x, fold(max(c0, c1)))) ||
rewrite(max(max(x, c0), y), max(max(x, y), c0)) ||
rewrite(max(x, max(y, c0)), max(max(x, y), c0)) ||
rewrite(max(max(x, y), x), a) ||
rewrite(max(max(x, y), y), a) ||
rewrite(max(x, max(x, y)), b) ||
rewrite(max(y, max(x, y)), b)) {
return rewrite.result;
} else {
return max(a, b);
}
}
Expr make_min_helper(const Expr &a, const Expr &b) {
auto rewrite = IRMatcher::rewriter(IRMatcher::min(a, b), a.type());
Expr pos_inf = Interval::pos_inf();
Expr neg_inf = Interval::neg_inf();
if (rewrite(min(x, x), x) ||
rewrite(min(x, pos_inf), x) ||
rewrite(min(pos_inf, x), x) ||
rewrite(min(x, neg_inf), neg_inf) ||
rewrite(min(neg_inf, x), neg_inf) ||
rewrite(min(c0, c1), fold(min(c0, c1))) ||
rewrite(min(c0, x), min(x, c0)) ||
rewrite(min(min(x, c0), c1), min(x, fold(min(c0, c1)))) ||
rewrite(min(min(x, c0), y), min(min(x, y), c0)) ||
rewrite(min(x, min(y, c0)), min(min(x, y), c0)) ||
rewrite(min(min(x, y), x), a) ||
rewrite(min(min(x, y), y), a) ||
rewrite(min(x, min(x, y)), b) ||
rewrite(min(y, min(x, y)), b)) {
return rewrite.result;
} else {
return min(a, b);
}
}
} // namespace
Interval Interval::everything() {
return Interval(neg_inf(), pos_inf());
}
Interval Interval::nothing() {
return Interval(pos_inf(), neg_inf());
}
Interval Interval::single_point(const Expr &e) {
return Interval(e, e);
}
bool Interval::is_empty() const {
return min.same_as(pos_inf()) || max.same_as(neg_inf());
}
bool Interval::is_everything() const {
return min.same_as(neg_inf()) && max.same_as(pos_inf());
}
bool Interval::is_single_point() const {
return min.same_as(max);
}
bool Interval::is_single_point(const Expr &e) const {
return min.same_as(e) && max.same_as(e);
}
bool Interval::has_upper_bound() const {
return !max.same_as(pos_inf()) && !is_empty();
}
bool Interval::has_lower_bound() const {
return !min.same_as(neg_inf()) && !is_empty();
}
bool Interval::is_bounded() const {
return has_upper_bound() && has_lower_bound();
}
bool Interval::same_as(const Interval &other) const {
return min.same_as(other.min) && max.same_as(other.max);
}
bool Interval::operator==(const Interval &other) const {
return (min.same_as(other.min)) && (max.same_as(other.max));
}
// This is called repeatedly by bounds inference and the solver to
// build large expressions, so we want to simplify eagerly to avoid
// monster expressions.
Expr Interval::make_max(const Expr &a, const Expr &b) {
return make_max_helper(a, b);
}
Expr Interval::make_min(const Expr &a, const Expr &b) {
return make_min_helper(a, b);
}
void Interval::include(const Interval &i) {
max = Interval::make_max(max, i.max);
min = Interval::make_min(min, i.min);
}
void Interval::include(const Expr &e) {
max = Interval::make_max(max, e);
min = Interval::make_min(min, e);
}
Interval Interval::make_union(const Interval &a, const Interval &b) {
Interval result = a;
result.include(b);
return result;
}
Interval Interval::make_intersection(const Interval &a, const Interval &b) {
return Interval(Interval::make_max(a.min, b.min),
Interval::make_min(a.max, b.max));
}
// Use Handle types for positive and negative infinity, to prevent
// accidentally doing arithmetic on them.
Expr Interval::pos_inf_expr = Variable::make(Handle(), "pos_inf");
Expr Interval::neg_inf_expr = Variable::make(Handle(), "neg_inf");
Expr Interval::pos_inf_noinline() {
return Interval::pos_inf_expr;
}
Expr Interval::neg_inf_noinline() {
return Interval::neg_inf_expr;
}
} // namespace Internal
} // namespace Halide