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| /*
* Copyright 2011 INRIA Saclay
* Copyright 2012 Ecole Normale Superieure
*
* Use of this software is governed by the MIT license
*
* Written by Sven Verdoolaege, INRIA Saclay - Ile-de-France,
* Parc Club Orsay Universite, ZAC des vignes, 4 rue Jacques Monod,
* 91893 Orsay, France
* and Ecole Normale Superieure, 45 rue d'Ulm, 75230 Paris, France
*/
#include <isl_pw_macro.h>
/* Given a function "cmp" that returns the set of elements where
* "el1" is "better" than "el2", return this set.
*/
static __isl_give isl_set *FN(PW,better)(__isl_keep EL *el1, __isl_keep EL *el2,
__isl_give isl_set *(*cmp)(__isl_take EL *el1, __isl_take EL *el2))
{
return cmp(FN(EL,copy)(el1), FN(EL,copy)(el2));
}
/* Return a list containing the domains of the pieces of "pw".
*/
static __isl_give isl_set_list *FN(PW,extract_domains)(__isl_keep PW *pw)
{
int i;
isl_ctx *ctx;
isl_set_list *list;
if (!pw)
return NULL;
ctx = FN(PW,get_ctx)(pw);
list = isl_set_list_alloc(ctx, pw->n);
for (i = 0; i < pw->n; ++i)
list = isl_set_list_add(list, isl_set_copy(pw->p[i].set));
return list;
}
/* Given sets B ("set"), C ("better") and A' ("out"), return
*
* (B \cap C) \cup ((B \setminus C) \setminus A')
*/
static __isl_give isl_set *FN(PW,better_or_out)(__isl_take isl_set *set,
__isl_take isl_set *better, __isl_take isl_set *out)
{
isl_set *set_better, *set_out;
set_better = isl_set_intersect(isl_set_copy(set), isl_set_copy(better));
set_out = isl_set_subtract(isl_set_subtract(set, better), out);
return isl_set_union(set_better, set_out);
}
/* Given sets A ("set"), C ("better") and B' ("out"), return
*
* (A \setminus C) \cup ((A \cap C) \setminus B')
*/
static __isl_give isl_set *FN(PW,worse_or_out)(__isl_take isl_set *set,
__isl_take isl_set *better, __isl_take isl_set *out)
{
isl_set *set_worse, *set_out;
set_worse = isl_set_subtract(isl_set_copy(set), isl_set_copy(better));
set_out = isl_set_subtract(isl_set_intersect(set, better), out);
return isl_set_union(set_worse, set_out);
}
/* Given two piecewise expressions "pw1" and "pw2", replace their domains
* by the sets in "list1" and "list2" and combine the results into
* a single piecewise expression.
* The pieces of "pw1" and "pw2" are assumed to have been sorted
* according to the function value expressions.
* The pieces of the result are also sorted in this way.
*
* Run through the pieces of "pw1" and "pw2" in order until they
* have both been exhausted, picking the piece from "pw1" or "pw2"
* depending on which should come first, together with the corresponding
* domain from "list1" or "list2". In cases where the next pieces
* in both "pw1" and "pw2" have the same function value expression,
* construct only a single piece in the result with as domain
* the union of the domains in "list1" and "list2".
*/
static __isl_give PW *FN(PW,merge)(__isl_take PW *pw1, __isl_take PW *pw2,
__isl_take isl_set_list *list1, __isl_take isl_set_list *list2)
{
int i, j;
PW *res;
if (!pw1 || !pw2)
goto error;
res = FN(PW,alloc_size)(isl_space_copy(pw1->dim), pw1->n + pw2->n);
i = 0; j = 0;
while (i < pw1->n || j < pw2->n) {
int cmp;
isl_set *set;
EL *el;
if (i < pw1->n && j < pw2->n)
cmp = FN(EL,plain_cmp)(pw1->p[i].FIELD,
pw2->p[j].FIELD);
else
cmp = i < pw1->n ? -1 : 1;
if (cmp < 0) {
set = isl_set_list_get_set(list1, i);
el = FN(EL,copy)(pw1->p[i].FIELD);
++i;
} else if (cmp > 0) {
set = isl_set_list_get_set(list2, j);
el = FN(EL,copy)(pw2->p[j].FIELD);
++j;
} else {
set = isl_set_union(isl_set_list_get_set(list1, i),
isl_set_list_get_set(list2, j));
el = FN(EL,copy)(pw1->p[i].FIELD);
++i;
++j;
}
res = FN(PW,add_piece)(res, set, el);
}
isl_set_list_free(list1);
isl_set_list_free(list2);
FN(PW,free)(pw1);
FN(PW,free)(pw2);
return res;
error:
isl_set_list_free(list1);
isl_set_list_free(list2);
FN(PW,free)(pw1);
FN(PW,free)(pw2);
return NULL;
}
/* Given a function "cmp" that returns the set of elements where
* "el1" is "better" than "el2", return a piecewise
* expression defined on the union of the definition domains
* of "pw1" and "pw2" that maps to the "best" of "pw1" and
* "pw2" on each cell. If only one of the two input functions
* is defined on a given cell, then it is considered the best.
*
* Run through all pairs of pieces in "pw1" and "pw2".
* If the domains of these pieces intersect, then the intersection
* needs to be distributed over the two pieces based on "cmp".
* Let C be the set where the piece from "pw2" is better (according to "cmp")
* than the piece from "pw1". Let A be the domain of the piece from "pw1" and
* B the domain of the piece from "pw2".
*
* The elements in C need to be removed from A, except for those parts
* that lie outside of B. That is,
*
* A <- (A \setminus C) \cup ((A \cap C) \setminus B')
*
* Conversely, the elements in B need to be restricted to C, except
* for those parts that lie outside of A. That is
*
* B <- (B \cap C) \cup ((B \setminus C) \setminus A')
*
* Since all pairs of pieces are considered, the domains are updated
* several times. A and B refer to these updated domains
* (kept track of in "list1" and "list2"), while A' and B' refer
* to the original domains of the pieces. It is safe to use these
* original domains because the difference between, say, A' and A is
* the domains of pw2-pieces that have been removed before and
* those domains are disjoint from B. A' is used instead of A
* because the continued updating of A may result in this domain
* getting broken up into more disjuncts.
*
* After the updated domains have been computed, the result is constructed
* from "pw1", "pw2", "list1" and "list2". If there are any pieces
* in "pw1" and "pw2" with the same function value expression, then
* they are combined into a single piece in the result.
* In order to be able to do this efficiently, the pieces of "pw1" and
* "pw2" are first sorted according to their function value expressions.
*/
static __isl_give PW *FN(PW,union_opt_cmp)(
__isl_take PW *pw1, __isl_take PW *pw2,
__isl_give isl_set *(*cmp)(__isl_take EL *el1, __isl_take EL *el2))
{
int i, j;
PW *res = NULL;
isl_ctx *ctx;
isl_set *set = NULL;
isl_set_list *list1 = NULL, *list2 = NULL;
if (!pw1 || !pw2)
goto error;
ctx = isl_space_get_ctx(pw1->dim);
if (!isl_space_is_equal(pw1->dim, pw2->dim))
isl_die(ctx, isl_error_invalid,
"arguments should live in the same space", goto error);
if (FN(PW,is_empty)(pw1)) {
FN(PW,free)(pw1);
return pw2;
}
if (FN(PW,is_empty)(pw2)) {
FN(PW,free)(pw2);
return pw1;
}
pw1 = FN(PW,sort)(pw1);
pw2 = FN(PW,sort)(pw2);
if (!pw1 || !pw2)
goto error;
list1 = FN(PW,extract_domains)(pw1);
list2 = FN(PW,extract_domains)(pw2);
for (i = 0; i < pw1->n; ++i) {
for (j = 0; j < pw2->n; ++j) {
isl_bool disjoint;
isl_set *better, *set_i, *set_j;
disjoint = isl_set_is_disjoint(pw1->p[i].set,
pw2->p[j].set);
if (disjoint < 0)
goto error;
if (disjoint)
continue;
better = FN(PW,better)(pw2->p[j].FIELD,
pw1->p[i].FIELD, cmp);
set_i = isl_set_list_get_set(list1, i);
set_j = isl_set_copy(pw2->p[j].set);
set_i = FN(PW,worse_or_out)(set_i,
isl_set_copy(better), set_j);
list1 = isl_set_list_set_set(list1, i, set_i);
set_i = isl_set_copy(pw1->p[i].set);
set_j = isl_set_list_get_set(list2, j);
set_j = FN(PW,better_or_out)(set_j, better, set_i);
list2 = isl_set_list_set_set(list2, j, set_j);
}
}
res = FN(PW,merge)(pw1, pw2, list1, list2);
return res;
error:
isl_set_list_free(list1);
isl_set_list_free(list2);
FN(PW,free)(pw1);
FN(PW,free)(pw2);
isl_set_free(set);
return FN(PW,free)(res);
}
|