Re: [PATCH PR82472]Update postorder number for merged partition.

[Richard Biener]

On Wed, Oct 11, 2017 at 12:06 PM, Bin Cheng  wrote:
> Hi,
> This patch fixes the reported ICE.  Root cause is postorder number is not 
> updated
> after merging partitions in SCC.  As a result, reduction partition may not be 
> scheduled
> as the last one because partitions are sorted in descending postorder.
> Bootstrap and test on x86_64 and AArch64.  Is it OK?

Ok.

Richard.

> Thanks,
> bin
> 2017-10-10  Bin Cheng  
>
> PR tree-optimization/82472
> * tree-loop-distribution.c (sort_partitions_by_post_order): Refine
> comment.
> (break_alias_scc_partitions): Update postorder number.
>
> gcc/testsuite
> 2017-10-10  Bin Cheng  
>
> PR tree-optimization/82472
> * gcc.dg/tree-ssa/pr82472.c: New test.

[PATCH PR82472]Update postorder number for merged partition.

[Bin Cheng]

Hi,
This patch fixes the reported ICE.  Root cause is postorder number is not 
updated
after merging partitions in SCC.  As a result, reduction partition may not be 
scheduled
as the last one because partitions are sorted in descending postorder.
Bootstrap and test on x86_64 and AArch64.  Is it OK?

Thanks,
bin
2017-10-10  Bin Cheng  

PR tree-optimization/82472
* tree-loop-distribution.c (sort_partitions_by_post_order): Refine
comment.
(break_alias_scc_partitions): Update postorder number.

gcc/testsuite
2017-10-10  Bin Cheng  

PR tree-optimization/82472
* gcc.dg/tree-ssa/pr82472.c: New test.diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr82472.c 
b/gcc/testsuite/gcc.dg/tree-ssa/pr82472.c
new file mode 100644
index 000..445c95f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr82472.c
@@ -0,0 +1,24 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ftree-loop-distribution" } */
+
+long int xj;
+
+int
+cx (long int *ox, short int mk, char tf)
+{
+  int si, f9;
+  char *p4 = 
+  short int *rm = (tf != 0) ? (short int *) : 
+
+  for (f9 = 0; f9 < 2; ++f9)
+{
+  *rm = 0;
+  *p4 = *ox;
+  si = mk;
+  xj = 0;
+  while (p4 < (char *)rm)
+++p4;
+}
+
+  return si;
+}
diff --git a/gcc/tree-loop-distribution.c b/gcc/tree-loop-distribution.c
index 26b8b9a..9ffac53 100644
--- a/gcc/tree-loop-distribution.c
+++ b/gcc/tree-loop-distribution.c
@@ -1939,7 +1939,8 @@ build_partition_graph (struct graph *rdg,
   return pg;
 }
 
-/* Sort partitions in PG by post order and store them in PARTITIONS.  */
+/* Sort partitions in PG in descending post order and store them in
+   PARTITIONS.  */
 
 static void
 sort_partitions_by_post_order (struct graph *pg,
@@ -1948,7 +1949,7 @@ sort_partitions_by_post_order (struct graph *pg,
   int i;
   struct pg_vdata *data;
 
-  /* Now order the remaining nodes in postorder.  */
+  /* Now order the remaining nodes in descending postorder.  */
   qsort (pg->vertices, pg->n_vertices, sizeof (vertex), pgcmp);
   partitions->truncate (0);
   for (i = 0; i < pg->n_vertices; ++i)
@@ -2044,7 +2045,7 @@ break_alias_scc_partitions (struct graph *rdg,
vec *partitions,
vec *alias_ddrs)
 {
-  int i, j, num_sccs, num_sccs_no_alias;
+  int i, j, k, num_sccs, num_sccs_no_alias;
   /* Build partition dependence graph.  */
   graph *pg = build_partition_graph (rdg, partitions, false);
 
@@ -2117,18 +2118,26 @@ break_alias_scc_partitions (struct graph *rdg,
  for (j = 0; partitions->iterate (j, ); ++j)
if (cbdata.vertices_component[j] == i)
  break;
- for (++j; partitions->iterate (j, ); ++j)
+ for (k = j + 1; partitions->iterate (k, ); ++k)
{
  struct pg_vdata *data;
 
- if (cbdata.vertices_component[j] != i)
+ if (cbdata.vertices_component[k] != i)
continue;
 
+ /* Update postorder number so that merged reduction partition is
+sorted after other partitions.  */
+ if (!partition_reduction_p (first)
+ && partition_reduction_p (partition))
+   {
+ gcc_assert (pg->vertices[k].post < pg->vertices[j].post);
+ pg->vertices[j].post = pg->vertices[k].post;
+   }
  partition_merge_into (NULL, first, partition, FUSE_SAME_SCC);
- (*partitions)[j] = NULL;
+ (*partitions)[k] = NULL;
  partition_free (partition);
- data = (struct pg_vdata *)pg->vertices[j].data;
- gcc_assert (data->id == j);
+ data = (struct pg_vdata *)pg->vertices[k].data;
+ gcc_assert (data->id == k);
  data->partition = NULL;
}
}