Revision 5deee77b677da97c4dadc966f76d8bf01d855c57 authored by Steven Johnson on 01 April 2020, 00:47:39 UTC, committed by Steven Johnson on 01 April 2020, 00:47:39 UTC
1 parent cb6f4a9
Interval.h
#ifndef HALIDE_INTERVAL_H
#define HALIDE_INTERVAL_H
/** \file
* Defines the Interval class
*/
#include "Error.h"
#include "Expr.h"
#include "runtime/HalideRuntime.h"
namespace Halide {
namespace Internal {
/** A class to represent ranges of Exprs. Can be unbounded above or below. */
struct Interval {
/** Exprs to represent positive and negative infinity */
#ifdef COMPILING_HALIDE
static HALIDE_ALWAYS_INLINE Expr pos_inf() {
return pos_inf_expr;
}
static HALIDE_ALWAYS_INLINE Expr neg_inf() {
return neg_inf_expr;
}
#else
static Expr pos_inf() {
return pos_inf_noinline();
}
static Expr neg_inf() {
return neg_inf_noinline();
}
#endif
/** The lower and upper bound of the interval. They are included
* in the interval. */
Expr min, max;
/** A default-constructed Interval is everything */
Interval()
: min(neg_inf()), max(pos_inf()) {
}
/** Construct an interval from a lower and upper bound. */
Interval(const Expr &min, const Expr &max)
: min(min), max(max) {
internal_assert(min.defined() && max.defined());
}
/** The interval representing everything. */
static Interval everything() {
return Interval(neg_inf(), pos_inf());
}
/** The interval representing nothing. */
static Interval nothing() {
return Interval(pos_inf(), neg_inf());
}
/** Construct an interval representing a single point */
static Interval single_point(const Expr &e) {
return Interval(e, e);
}
/** Is the interval the empty set */
bool is_empty() const {
return min.same_as(pos_inf()) || max.same_as(neg_inf());
}
/** Is the interval the entire range */
bool is_everything() const {
return min.same_as(neg_inf()) && max.same_as(pos_inf());
}
/** Is the interval just a single value (min == max) */
bool is_single_point() const {
return min.same_as(max);
}
/** Is the interval a particular single value */
bool is_single_point(const Expr &e) const {
return min.same_as(e) && max.same_as(e);
}
/** Does the interval have a finite least upper bound */
bool has_upper_bound() const {
return !max.same_as(pos_inf()) && !is_empty();
}
/** Does the interval have a finite greatest lower bound */
bool has_lower_bound() const {
return !min.same_as(neg_inf()) && !is_empty();
}
/** Does the interval have a finite upper and lower bound */
bool is_bounded() const {
return has_upper_bound() && has_lower_bound();
}
/** Is the interval the same as another interval */
bool same_as(const Interval &other) {
return min.same_as(other.min) && max.same_as(other.max);
}
/** Expand the interval to include another Interval */
void include(const Interval &i);
/** Expand the interval to include an Expr */
void include(const Expr &e);
/** Construct the smallest interval containing two intervals. */
static Interval make_union(const Interval &a, const Interval &b);
/** Construct the largest interval contained within two intervals. */
static Interval make_intersection(const Interval &a, const Interval &b);
/** An eagerly-simplifying max of two Exprs that respects infinities. */
static Expr make_max(const Expr &a, const Expr &b);
/** An eagerly-simplifying min of two Exprs that respects infinities. */
static Expr make_min(const Expr &a, const Expr &b);
bool operator==(const Interval &other) const {
return (min.same_as(other.min)) && (max.same_as(other.max));
}
private:
static Expr neg_inf_expr, pos_inf_expr;
// Never used inside libHalide; provided for Halide tests, to avoid needing to export
// data fields in some build environments.
static Expr pos_inf_noinline();
static Expr neg_inf_noinline();
};
} // namespace Internal
} // namespace Halide
#endif
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