Merge branch 'maint'

[platform/upstream/isl.git] / isl_morph.c

diff --git a/isl_morph.c b/isl_morph.c
index 0d007e1..bd5733d 100644 (file)
--- a/isl_morph.c
+++ b/isl_morph.c
@@ -172,6 +172,7 @@ __isl_give isl_morph *isl_morph_dom_params(__isl_take isl_morph *morph)
 {
        unsigned n;
 
+       morph = isl_morph_cow(morph);
        if (!morph)
                return NULL;
        n = isl_basic_set_dim(morph->dom, isl_dim_set);
@@ -192,6 +193,7 @@ __isl_give isl_morph *isl_morph_ran_params(__isl_take isl_morph *morph)
 {
        unsigned n;
 
+       morph = isl_morph_cow(morph);
        if (!morph)
                return NULL;
        n = isl_basic_set_dim(morph->ran, isl_dim_set);
@@ -314,7 +316,7 @@ error:
        return NULL;
 }
 
-/* Given a basic set, exploit the equalties in the a basic set to construct
+/* Given a basic set, exploit the equalties in the basic set to construct
  * a morphishm that maps the basic set to a lower-dimensional space.
  * Specifically, the morphism reduces the number of dimensions of type "type".
  *
@@ -782,12 +784,20 @@ __isl_give isl_morph *isl_morph_inverse(__isl_take isl_morph *morph)
        return morph;
 }
 
+/* We detect all the equalities first to avoid implicit equalties
+ * being discovered during the computations.  In particular,
+ * the compression on the variables could expose additional stride
+ * constraints on the parameters.  This would result in existentially
+ * quantified variables after applying the resulting morph, which
+ * in turn could break invariants of the calling functions.
+ */
 __isl_give isl_morph *isl_basic_set_full_compression(
        __isl_keep isl_basic_set *bset)
 {
        isl_morph *morph, *morph2;
 
        bset = isl_basic_set_copy(bset);
+       bset = isl_basic_set_detect_equalities(bset);
 
        morph = isl_basic_set_variable_compression(bset, isl_dim_param);
        bset = isl_morph_basic_set(isl_morph_copy(morph), bset);