return isl_set_max(build->domain, obj, opt);
}
+/* Compute the "opposite" of the (numerator of the) argument of a div
+ * with denonimator "d".
+ *
+ * In particular, compute
+ *
+ * -aff + (d - 1)
+ */
+static __isl_give isl_aff *oppose_div_arg(__isl_take isl_aff *aff, isl_int d)
+{
+ aff = isl_aff_neg(aff);
+ aff = isl_aff_add_constant(aff, d);
+ aff = isl_aff_add_constant_si(aff, -1);
+
+ return aff;
+}
+
/* Create an isl_ast_expr evaluating the div at position "pos" in "ls".
* The result is simplified in terms of build->domain.
*
+ * "v" points to the coefficient of the div in the expression where it
+ * appears and may be updated by this function.
* "ls" is known to be non-NULL.
*
* Let the div be of the form floor(e/d).
*
* (fdiv_q, expr(e), expr(d))
*
+ * If the ast_build_prefer_pdiv option is set and
+ * if "e" is not non-negative, then we check if "-e + d - 1" is non-negative.
+ * If so, we can rewrite
+ *
+ * floor(e/d) = -ceil(-e/d) = -floor((-e + d - 1)/d)
+ *
+ * and still use pdiv_q.
*/
-static __isl_give isl_ast_expr *var_div(__isl_keep isl_local_space *ls,
+static __isl_give isl_ast_expr *var_div(isl_int *v,
+ __isl_keep isl_local_space *ls,
int pos, __isl_keep isl_ast_build *build)
{
isl_ctx *ctx = isl_local_space_get_ctx(ls);
isl_aff_get_denominator(aff, &d);
aff = isl_aff_scale(aff, d);
den = isl_ast_expr_alloc_int(ctx, d);
- isl_int_clear(d);
type = isl_ast_op_fdiv_q;
if (isl_options_get_ast_build_prefer_pdiv(ctx)) {
int non_neg = isl_ast_build_aff_is_nonneg(build, aff);
+ if (non_neg >= 0 && !non_neg) {
+ isl_aff *opp = oppose_div_arg(isl_aff_copy(aff), d);
+ non_neg = isl_ast_build_aff_is_nonneg(build, opp);
+ if (non_neg >= 0 && non_neg) {
+ isl_int_neg(*v, *v);
+ isl_aff_free(aff);
+ aff = opp;
+ } else
+ isl_aff_free(opp);
+ }
if (non_neg < 0)
aff = isl_aff_free(aff);
else if (non_neg)
type = isl_ast_op_pdiv_q;
}
+ isl_int_clear(d);
num = isl_ast_expr_from_aff(aff, build);
return isl_ast_expr_alloc_binary(type, num, den);
}
/* Create an isl_ast_expr evaluating the specified dimension of "ls".
* The result is simplified in terms of build->domain.
*
+ * "v" points to the coefficient of the specified dimension
+ * in the expression where it appears and may be updated by this function.
+ *
* The isl_ast_expr is constructed based on the type of the dimension.
* - divs are constructed by var_div
* - set variables are constructed from the iterator isl_ids in "build"
* - parameters are constructed from the isl_ids in "ls"
*/
-static __isl_give isl_ast_expr *var(__isl_keep isl_local_space *ls,
+static __isl_give isl_ast_expr *var(isl_int *v, __isl_keep isl_local_space *ls,
enum isl_dim_type type, int pos, __isl_keep isl_ast_build *build)
{
isl_ctx *ctx = isl_local_space_get_ctx(ls);
isl_id *id;
if (type == isl_dim_div)
- return var_div(ls, pos, build);
+ return var_div(v, ls, pos, build);
if (type == isl_dim_set) {
id = isl_ast_build_get_iterator_id(build, pos);
return expr;
}
-/* Create an isl_ast_expr evaluating "v" times the specified dimension of "ls".
- * The result is simplified in terms of build->domain.
+/* Create an isl_ast_expr that scales "expr" by "v".
*
- * Let e be the expression for the specified dimension.
- * If v is 1, we simply return e.
+ * If v is 1, we simply return expr.
* If v is -1, we return
*
- * (isl_ast_op_minus, e)
+ * (isl_ast_op_minus, expr)
*
* Otherwise, we return
*
- * (isl_ast_op_mul, expr(v), e)
+ * (isl_ast_op_mul, expr(v), expr)
*/
-static __isl_give isl_ast_expr *isl_ast_expr_term(
- __isl_keep isl_local_space *ls, enum isl_dim_type type, int pos,
- isl_int v, __isl_keep isl_ast_build *build)
+static __isl_give isl_ast_expr *scale(__isl_take isl_ast_expr *expr, isl_int v)
{
isl_ctx *ctx;
- isl_ast_expr *expr;
isl_ast_expr *c;
- if (!ls)
+ if (!expr)
return NULL;
+ if (isl_int_is_one(v))
+ return expr;
- ctx = isl_local_space_get_ctx(ls);
- expr = var(ls, type, pos, build);
-
- if (!isl_int_is_one(v)) {
- if (isl_int_is_negone(v)) {
- expr = isl_ast_expr_neg(expr);
- } else {
- c = isl_ast_expr_alloc_int(ctx, v);
- expr = isl_ast_expr_mul(c, expr);
- }
+ if (isl_int_is_negone(v)) {
+ expr = isl_ast_expr_neg(expr);
+ } else {
+ ctx = isl_ast_expr_get_ctx(expr);
+ c = isl_ast_expr_alloc_int(ctx, v);
+ expr = isl_ast_expr_mul(c, expr);
}
return expr;
}
-/* Add an expression for "v" times the specified dimension of "ls"
+/* Add an expression for "*v" times the specified dimension of "ls"
* to expr.
*
- * Let e be the expression for the specified dimension.
- * If "v" is negative, we create
+ * Let e be the expression for the specified dimension,
+ * multiplied by the absolute value of "*v".
+ * If "*v" is negative, we create
*
* (isl_ast_op_sub, expr, e)
*
*
* instead.
*
- * If "v" is positive, we simply create
+ * If "*v" is positive, we simply create
*
* (isl_ast_op_add, expr, e)
*
static __isl_give isl_ast_expr *isl_ast_expr_add_term(
__isl_take isl_ast_expr *expr,
__isl_keep isl_local_space *ls, enum isl_dim_type type, int pos,
- isl_int v, __isl_keep isl_ast_build *build)
+ isl_int *v, __isl_keep isl_ast_build *build)
{
isl_ast_expr *term;
if (!expr)
return NULL;
- if (isl_int_is_neg(v) && !ast_expr_is_zero(expr)) {
- isl_int_neg(v, v);
- term = isl_ast_expr_term(ls, type, pos, v, build);
+ term = var(v, ls, type, pos, build);
+
+ if (isl_int_is_neg(*v) && !ast_expr_is_zero(expr)) {
+ isl_int_neg(*v, *v);
+ term = scale(term, *v);
return ast_expr_sub(expr, term);
} else {
- term = isl_ast_expr_term(ls, type, pos, v, build);
+ term = scale(term, *v);
return ast_expr_add(expr, term);
}
}
* (isl_ast_op_pdiv_r, a, m)
*
* we need to make sure that a is non-negative.
+ * If not, we check if "-a + m - 1" is non-negative.
+ * If so, we can rewrite
+ *
+ * floor(a/m) = -ceil(-a/m) = -floor((-a + m - 1)/m)
+ *
+ * and still extract a modulo.
*
* The caller is responsible for dividing *neg and/or *pos by d.
*/
div = isl_aff_get_div(aff, j);
isl_aff_get_denominator(div, &d);
mod = isl_int_is_divisible_by(v, d);
- if (mod)
+ if (mod) {
+ div = isl_aff_scale(div, d);
mod = isl_ast_build_aff_is_nonneg(build, div);
+ if (mod >= 0 && !mod) {
+ isl_aff *opp = oppose_div_arg(isl_aff_copy(div), d);
+ mod = isl_ast_build_aff_is_nonneg(build, opp);
+ if (mod >= 0 && mod) {
+ isl_aff_free(div);
+ div = opp;
+ isl_int_neg(v, v);
+ } else
+ isl_aff_free(opp);
+ }
+ }
if (mod < 0) {
isl_aff_free(div);
isl_int_clear(d);
isl_int_clear(d);
return aff;
}
- div = isl_aff_scale(div, d);
isl_int_divexact(v, v, d);
s = isl_int_sgn(v);
isl_int_abs(v, v);
if (isl_int_is_zero(v))
continue;
expr = isl_ast_expr_add_term(expr,
- ls, l[i], j, v, build);
+ ls, l[i], j, &v, build);
}
}
continue;
isl_int_abs(v, v);
expr = isl_ast_expr_add_term(expr,
- ls, l[i], j, v, build);
+ ls, l[i], j, &v, build);
}
}
projects / platform / upstream / isl.git / blobdiff