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isl_map_simplify.c: eliminate_unit_divs: extract out eliminate_unit_div
authorSven Verdoolaege <sven.verdoolaege@gmail.com>
Sat, 25 Apr 2020 14:05:33 +0000 (25 16:05 +0200)
committerSven Verdoolaege <sven.verdoolaege@gmail.com>
Sat, 25 Apr 2020 15:14:51 +0000 (25 17:14 +0200)
The function eliminate_unit_divs is fairly long and will be further
extended in the next commit.  Extract out part of the body
to make it a bit shorter.

Signed-off-by: Sven Verdoolaege <sven.verdoolaege@gmail.com>
isl_map_simplify.c patch | blob | blame | history

diff --git a/isl_map_simplify.c b/isl_map_simplify.c
index 4253c5e..02b2b8d 100644 (file)
--- a/isl_map_simplify.c
+++ b/isl_map_simplify.c
@@ -1322,8 +1322,9 @@ __isl_give isl_basic_map *isl_basic_map_detect_inequality_pairs(
        return bmap;
 }
 
-/* Eliminate known divs from constraints where they appear with
- * a (positive or negative) unit coefficient.
+/* Given a known integer division "div" that is not integral
+ * (with denominator 1), eliminate it from the constraints in "bmap"
+ * where it appears with a (positive or negative) unit coefficient.
  * If "progress" is not NULL, then it gets set if the elimination
  * results in any changes.
  *
@@ -1355,6 +1356,61 @@ __isl_give isl_basic_map *isl_basic_map_detect_inequality_pairs(
  * being modified by this function.  The modified constraint may
  * no longer imply this div constraint, so we add it back to make
  * sure we do not lose any information.
+ */
+static __isl_give isl_basic_map *eliminate_unit_div(
+       __isl_take isl_basic_map *bmap, int div, int *progress)
+{
+       int j;
+       isl_size v_div, dim;
+       isl_ctx *ctx;
+
+       v_div = isl_basic_map_var_offset(bmap, isl_dim_div);
+       dim = isl_basic_map_dim(bmap, isl_dim_all);
+       if (v_div < 0 || dim < 0)
+               return isl_basic_map_free(bmap);
+
+       ctx = isl_basic_map_get_ctx(bmap);
+
+       for (j = 0; j < bmap->n_ineq; ++j) {
+               int s;
+
+               if (!isl_int_is_one(bmap->ineq[j][1 + v_div + div]) &&
+                   !isl_int_is_negone(bmap->ineq[j][1 + v_div + div]))
+                       continue;
+
+               if (progress)
+                       *progress = 1;
+
+               s = isl_int_sgn(bmap->ineq[j][1 + v_div + div]);
+               isl_int_set_si(bmap->ineq[j][1 + v_div + div], 0);
+               if (s < 0)
+                       isl_seq_combine(bmap->ineq[j],
+                               ctx->negone, bmap->div[div] + 1,
+                               bmap->div[div][0], bmap->ineq[j], 1 + dim);
+               else
+                       isl_seq_combine(bmap->ineq[j],
+                               ctx->one, bmap->div[div] + 1,
+                               bmap->div[div][0], bmap->ineq[j], 1 + dim);
+               if (s < 0) {
+                       isl_int_add(bmap->ineq[j][0],
+                               bmap->ineq[j][0], bmap->div[div][0]);
+                       isl_int_sub_ui(bmap->ineq[j][0],
+                               bmap->ineq[j][0], 1);
+               }
+
+               bmap = isl_basic_map_extend_constraints(bmap, 0, 1);
+               bmap = isl_basic_map_add_div_constraint(bmap, div, s);
+               if (!bmap)
+                       return NULL;
+       }
+
+       return bmap;
+}
+
+/* Eliminate known divs from constraints where they appear with
+ * a (positive or negative) unit coefficient.
+ * If "progress" is not NULL, then it gets set if the elimination
+ * results in any changes.
  *
  * We skip integral divs, i.e., those with denominator 1, as we would
  * risk eliminating the div from the div constraints.  We do not need
@@ -1365,55 +1421,19 @@ __isl_give isl_basic_map *isl_basic_map_detect_inequality_pairs(
 static __isl_give isl_basic_map *eliminate_unit_divs(
        __isl_take isl_basic_map *bmap, int *progress)
 {
-       int i, j;
-       isl_ctx *ctx;
-       unsigned total;
+       int i;
 
        if (!bmap)
                return NULL;
 
-       ctx = isl_basic_map_get_ctx(bmap);
-       total = isl_basic_map_offset(bmap, isl_dim_div);
-
        for (i = 0; i < bmap->n_div; ++i) {
                if (isl_int_is_zero(bmap->div[i][0]))
                        continue;
                if (isl_int_is_one(bmap->div[i][0]))
                        continue;
-               for (j = 0; j < bmap->n_ineq; ++j) {
-                       int s;
-
-                       if (!isl_int_is_one(bmap->ineq[j][total + i]) &&
-                           !isl_int_is_negone(bmap->ineq[j][total + i]))
-                               continue;
-
-                       if (progress)
-                               *progress = 1;
-
-                       s = isl_int_sgn(bmap->ineq[j][total + i]);
-                       isl_int_set_si(bmap->ineq[j][total + i], 0);
-                       if (s < 0)
-                               isl_seq_combine(bmap->ineq[j],
-                                       ctx->negone, bmap->div[i] + 1,
-                                       bmap->div[i][0], bmap->ineq[j],
-                                       total + bmap->n_div);
-                       else
-                               isl_seq_combine(bmap->ineq[j],
-                                       ctx->one, bmap->div[i] + 1,
-                                       bmap->div[i][0], bmap->ineq[j],
-                                       total + bmap->n_div);
-                       if (s < 0) {
-                               isl_int_add(bmap->ineq[j][0],
-                                       bmap->ineq[j][0], bmap->div[i][0]);
-                               isl_int_sub_ui(bmap->ineq[j][0],
-                                       bmap->ineq[j][0], 1);
-                       }
-
-                       bmap = isl_basic_map_extend_constraints(bmap, 0, 1);
-                       bmap = isl_basic_map_add_div_constraint(bmap, i, s);
-                       if (!bmap)
-                               return NULL;
-               }
+               bmap = eliminate_unit_div(bmap, i, progress);
+               if (!bmap)
+                       return NULL;
        }
 
        return bmap;
Integer set library