From b4ec1d31a5d605c8bea45ca919d3a60dfdac771f Mon Sep 17 00:00:00 2001
From: Bin Cheng <bin.cheng@arm.com>
Date: Wed, 11 Oct 2017 13:04:05 +0000
Subject: [PATCH] re PR tree-optimization/82472 (ICE in
 generate_code_for_partition, at tree-loop-distribution.c:1145)

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

	gcc/testsuite
	* gcc.dg/tree-ssa/pr82472.c: New test.

From-SVN: r253641
---
 gcc/ChangeLog                           |  7 +++++++
 gcc/testsuite/ChangeLog                 |  5 +++++
 gcc/testsuite/gcc.dg/tree-ssa/pr82472.c | 24 ++++++++++++++++++++++++
 gcc/tree-loop-distribution.c            | 25 +++++++++++++++++--------
 4 files changed, 53 insertions(+), 8 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr82472.c

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7dba1098f6a..0028fc9a38a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2017-10-11  Bin Cheng  <bin.cheng@arm.com>
+
+	PR tree-optimization/82472
+	* tree-loop-distribution.c (sort_partitions_by_post_order): Refine
+	comment.
+	(break_alias_scc_partitions): Update postorder number.
+
 2017-10-11  Martin Liska  <mliska@suse.cz>
 
 	PR sanitizer/82490
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 04adb938767..23fccba5a67 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2017-10-11  Bin Cheng  <bin.cheng@arm.com>
+
+	PR tree-optimization/82472
+	* gcc.dg/tree-ssa/pr82472.c: New test.
+
 2017-10-11  Martin Liska  <mliska@suse.cz>
 
 	PR sanitizer/82490
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 00000000000..445c95fbc47
--- /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 = &tf;
+  short int *rm = (tf != 0) ? (short int *)&f9 : &mk;
+
+  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 999b32ef06c..98ad50e5e7a 100644
--- a/gcc/tree-loop-distribution.c
+++ b/gcc/tree-loop-distribution.c
@@ -1943,7 +1943,8 @@ 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,
@@ -1952,7 +1953,7 @@ 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)
@@ -2048,7 +2049,7 @@ break_alias_scc_partitions (struct graph *rdg,
 			    vec<struct partition *> *partitions,
 			    vec<ddr_p> *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);
 
@@ -2121,18 +2122,26 @@ break_alias_scc_partitions (struct graph *rdg,
 	  for (j = 0; partitions->iterate (j, &first); ++j)
 	    if (cbdata.vertices_component[j] == i)
 	      break;
-	  for (++j; partitions->iterate (j, &partition); ++j)
+	  for (k = j + 1; partitions->iterate (k, &partition); ++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;
 	    }
 	}
-- 
2.30.2