| Message ID | df503963-2b9d-cc87-ece9-e85ca0766ed6@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | PR tree-optimization/105458 - Check for equivalence after merging relations. | expand |
On Tue, May 17, 2022 at 5:46 PM Andrew MacLeod via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > Sorry, missed this one earlier. > > When we register a relation, such as LE_EXPR, we first check if there > is an existing relation that applies, and if so they are combined. We > were checking if the relation being registered was an EQ_EXPR, and if > so, invoked the equivalence oracle. > > I was doing the check for EQ_EXPR first, then merging with any > existing relation. In this case, the merge resulted in transforming > the LE_EXPR into an EQ_EXPR, but the check to invoke the > equivalence_oracle had already been done, and we got to a place we > shouldn't have. doh! > > The fix is to do the merge first, then check for EQ_EXPR. > > The patch is a hair different (due to VREL_* renames in gcc13), so I've > attached both patches. > > bootstraps on gcc12 and gcc13 with no regressions. pushed on trunk. > > OK for GCC12? OK > Andrew
commit c48fe8d3430e81ddea621c24e9b66d55aadfb316
Author: Andrew MacLeod <amacleod@redhat.com>
Date: Tue May 17 09:36:39 2022 -0400
Check for equivalence after merging relations.
When registering a relation, we need to merge with any existing relation
before checking if it was an equivalence... otherwise it was not being
handled properly.
gcc/
PR tree-optimization/105458
* value-relation.cc (path_oracle::register_relation): Merge, then check
for equivalence.
gcc/testsuite/
* gcc.dg/pr105458.c: New.
diff --git a/gcc/testsuite/gcc.dg/pr105458.c b/gcc/testsuite/gcc.dg/pr105458.c
new file mode 100644
index 00000000000..eb58bf21f32
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr105458.c
@@ -0,0 +1,20 @@
+/* PR tree-optimization/105458 */
+/* { dg-do compile } */
+/* { dg-options "-O1 -fexpensive-optimizations -fno-tree-dominator-opts " } */
+
+void
+yj (int j4)
+{
+ int t3;
+
+ for (t3 = 0; t3 < 6; ++t3)
+ {
+ short int v4 = t3;
+
+ if (v4 == j4 || v4 > t3)
+ for (;;)
+ {
+ }
+ }
+}
+
diff --git a/gcc/value-relation.cc b/gcc/value-relation.cc
index 077ab4230a7..a69ad080e47 100644
--- a/gcc/value-relation.cc
+++ b/gcc/value-relation.cc
@@ -1388,16 +1388,16 @@ path_oracle::register_relation (basic_block bb, relation_kind k, tree ssa1,
fprintf (dump_file, " (root: bb%d)\n", bb->index);
}
+ relation_kind curr = query_relation (bb, ssa1, ssa2);
+ if (curr != VREL_NONE)
+ k = relation_intersect (curr, k);
+
if (k == EQ_EXPR)
{
register_equiv (bb, ssa1, ssa2);
return;
}
- relation_kind curr = query_relation (bb, ssa1, ssa2);
- if (curr != VREL_NONE)
- k = relation_intersect (curr, k);
-
bitmap_set_bit (m_relations.m_names, SSA_NAME_VERSION (ssa1));
bitmap_set_bit (m_relations.m_names, SSA_NAME_VERSION (ssa2));
relation_chain *ptr = (relation_chain *) obstack_alloc (&m_chain_obstack,