RDom.cpp
#include "RDom.h"
#include "Util.h"
#include "ImageParam.h"
#include "IREquality.h"
#include "IROperator.h"
#include "IRPrinter.h"
#include "Simplify.h"
#include "Generator.h"
namespace Halide {
using namespace Internal;
using std::string;
using std::vector;
namespace {
static const char * const dom_var_names[] = {"$x", "$y", "$z", "$w"};
// T is an ImageParam, Buffer<>, Input<Buffer<>>
template<typename T>
Internal::ReductionDomain make_dom_from_dimensions(const T &t, const std::string &name) {
std::vector<Internal::ReductionVariable> vars;
for (int i = 0; i < t.dimensions(); i++) {
vars.push_back({
name + dom_var_names[i],
t.dim(i).min(),
t.dim(i).extent()
});
}
return Internal::ReductionDomain(vars);
}
} // namespace
RVar::operator Expr() const {
if (!min().defined() || !extent().defined()) {
user_error << "Use of undefined RDom dimension: " <<
(name().empty() ? "<unknown>" : name()) << "\n";
}
return Variable::make(Int(32), name(), domain());
}
Expr RVar::min() const {
if (_domain.defined()) {
return _var().min;
} else {
return Expr();
}
}
Expr RVar::extent() const {
if (_domain.defined()) {
return _var().extent;
} else {
return Expr();
}
}
const std::string &RVar::name() const {
if (_domain.defined()) {
return _var().var;
} else {
return _name;
}
}
template <int N>
ReductionDomain build_domain(ReductionVariable (&vars)[N]) {
vector<ReductionVariable> d(&vars[0], &vars[N]);
ReductionDomain dom(d);
return dom;
}
// This just initializes the predefined x, y, z, w members of RDom.
void RDom::init_vars(const string &name) {
const std::vector<ReductionVariable> &dom_vars = dom.domain();
RVar *vars[] = { &x, &y, &z, &w };
for (size_t i = 0; i < sizeof(vars)/sizeof(vars[0]); i++) {
if (i < dom_vars.size()) {
*(vars[i]) = RVar(dom, i);
} else {
*(vars[i]) = RVar(name + dom_var_names[i]);
}
}
}
RDom::RDom(ReductionDomain d) : dom(d) {
if (d.defined()) {
init_vars("");
}
}
namespace {
class CheckRDomBounds : public IRGraphVisitor {
using IRGraphVisitor::visit;
void visit(const Call *op) {
IRGraphVisitor::visit(op);
if (op->call_type == Call::Halide) {
offending_func = op->name;
}
}
void visit(const Variable *op) {
if (!op->param.defined() && !op->image.defined()) {
offending_free_var = op->name;
}
}
public:
string offending_func;
string offending_free_var;
};
}
void RDom::initialize_from_ranges(const std::vector<std::pair<Expr, Expr>> &ranges, string name) {
if (name.empty()) {
name = make_entity_name(this, "Halide::RDom", 'r');
}
std::vector<ReductionVariable> vars;
for (size_t i = 0; i < ranges.size(); i++) {
CheckRDomBounds checker;
user_assert(ranges[i].first.defined() && ranges[i].second.defined())
<< "The RDom " << name << " may not be constructed with undefined Exprs.\n";
ranges[i].first.accept(&checker);
ranges[i].second.accept(&checker);
user_assert(checker.offending_func.empty())
<< "The bounds of the RDom " << name
<< " in dimension " << i
<< " are:\n"
<< " " << ranges[i].first << " ... " << ranges[i].second << "\n"
<< "These depend on a call to the Func " << checker.offending_func << ".\n"
<< "The bounds of an RDom may not depend on a call to a Func.\n";
user_assert(checker.offending_free_var.empty())
<< "The bounds of the RDom " << name
<< " in dimension " << i
<< " are:\n"
<< " " << ranges[i].first << " ... " << ranges[i].second << "\n"
<< "These depend on the variable " << checker.offending_free_var << ".\n"
<< "The bounds of an RDom may not depend on a free variable.\n";
std::string rvar_uniquifier;
switch (i) {
case 0: rvar_uniquifier = "x"; break;
case 1: rvar_uniquifier = "y"; break;
case 2: rvar_uniquifier = "z"; break;
case 3: rvar_uniquifier = "w"; break;
default: rvar_uniquifier = std::to_string(i); break;
}
ReductionVariable rv;
rv.var = name + "$" + rvar_uniquifier;
rv.min = cast<int32_t>(ranges[i].first);
rv.extent = cast<int32_t>(ranges[i].second);
vars.push_back(rv);
}
dom = ReductionDomain(vars);
init_vars(name);
}
RDom::RDom(const Buffer<> &b) {
std::string name = unique_name('r');
dom = make_dom_from_dimensions(b, name);
init_vars(name);
}
RDom::RDom(const OutputImageParam &p) {
std::string name = p.name();
dom = make_dom_from_dimensions(p, name);
init_vars(name);
}
int RDom::dimensions() const {
return (int)dom.domain().size();
}
RVar RDom::operator[](int i) const {
if (i == 0) return x;
if (i == 1) return y;
if (i == 2) return z;
if (i == 3) return w;
if (i < dimensions()) {
return RVar(dom, i);
}
user_error << "Reduction domain index out of bounds: " << i << "\n";
return x; // Keep the compiler happy
}
RDom::operator Expr() const {
if (dimensions() != 1) {
user_error << "Error: Can't treat this multidimensional RDom as an Expr:\n"
<< (*this) << "\n"
<< "Only single-dimensional RDoms can be cast to Expr.\n";
}
return Expr(x);
}
RDom::operator RVar() const {
if (dimensions() != 1) {
user_error << "Error: Can't treat this multidimensional RDom as an RVar:\n"
<< (*this) << "\n"
<< "Only single-dimensional RDoms can be cast to RVar.\n";
}
return x;
}
void RDom::where(Expr predicate) {
user_assert(!dom.frozen())
<< (*this) << " cannot be given a new predicate, because it has already"
<< " been used in the update definition of some function.\n";
user_assert(dom.defined()) << "Error: Can't add predicate to undefined RDom.\n";
dom.where(predicate);
}
/** Emit an RVar in a human-readable form */
std::ostream &operator<<(std::ostream &stream, RVar v) {
stream << v.name() << "(" << v.min() << ", " << v.extent() << ")";
return stream;
}
/** Emit an RDom in a human-readable form. */
std::ostream &operator<<(std::ostream &stream, RDom dom) {
stream << "RDom(\n";
for (int i = 0; i < dom.dimensions(); i++) {
stream << " " << dom[i] << "\n";
}
stream << ")";
Expr pred = simplify(dom.domain().predicate());
if (!equal(const_true(), pred)) {
stream << " where (\n " << pred << ")";
}
stream << "\n";
return stream;
}
}