#ifndef HALIDE_SUBSTITUTE_H
#define HALIDE_SUBSTITUTE_H
/** \file
*
* Defines methods for substituting out variables in expressions and
* statements. */
#include <map>
#include "IR.h"
namespace Halide {
namespace Internal {
/** Substitute variables with the given name with the replacement
* expression within expr. This is a dangerous thing to do if variable
* names have not been uniquified. While it won't traverse inside let
* statements with the same name as the first argument, moving a piece
* of syntax around can change its meaning, because it can cross lets
* that redefine variable names that it includes references to. */
EXPORT Expr substitute(const std::string &name, const Expr &replacement, const Expr &expr);
/** Substitute variables with the given name with the replacement
* expression within stmt. */
EXPORT Stmt substitute(const std::string &name, const Expr &replacement, const Stmt &stmt);
/** Substitute variables with names in the map. */
// @{
EXPORT Expr substitute(const std::map<std::string, Expr> &replacements, const Expr &expr);
EXPORT Stmt substitute(const std::map<std::string, Expr> &replacements, const Stmt &stmt);
// @}
/** Substitute expressions for other expressions. */
// @{
EXPORT Expr substitute(const Expr &find, const Expr &replacement, const Expr &expr);
EXPORT Stmt substitute(const Expr &find, const Expr &replacement, const Stmt &stmt);
// @}
/** Substitutions where the IR may be a general graph (and not just a
* DAG). */
// @{
Expr graph_substitute(const std::string &name, const Expr &replacement, const Expr &expr);
Stmt graph_substitute(const std::string &name, const Expr &replacement, const Stmt &stmt);
Expr graph_substitute(const Expr &find, const Expr &replacement, const Expr &expr);
Stmt graph_substitute(const Expr &find, const Expr &replacement, const Stmt &stmt);
// @}
/** Substitute in all let Exprs in a piece of IR. Doesn't substitute
* in let stmts, as this may change the meaning of the IR (e.g. by
* moving a load after a store). Produces graphs of IR, so don't use
* non-graph-aware visitors or mutators on it until you've CSE'd the
* result. */
// @{
Expr substitute_in_all_lets(const Expr &expr);
Stmt substitute_in_all_lets(const Stmt &stmt);
// @}
}
}
#endif