re PR tree-optimization/79977 ([graphite] ICE in outermost_loop_in_sese, at sese.c:300 w/ -O2 -floop-nest-optimize)

2017-03-09  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/79977
	* graphite-scop-detection.c (scop_detection::merge_sese):
	Handle the case of extra exits to blocks dominating the entry.

	* gcc.dg/graphite/pr79977.c: New testcase.

From-SVN: r246006

gcc/ChangeLog

@@ -1,3 +1,9 @@
+2017-03-09  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/79977
+	* graphite-scop-detection.c (scop_detection::merge_sese):
+	Handle the case of extra exits to blocks dominating the entry.
+
 2017-03-09  Toma Tabacu  <toma.tabacu@imgtec.com>
 
 	* doc/sourcebuild.texi (Effective-Target Keywords, Other attributes):

gcc/graphite-scop-detection.c

@@ -817,6 +817,25 @@ scop_detection::merge_sese (sese_l first, sese_l second) const
 	 != loop_depth (exit->dest->loop_father))
     return invalid_sese;
 
+  /* For now we just bail out when there is a loop exit in the region
+     that is not also the exit of the region.  We could enlarge the
+     region to cover the loop that region exits to.  See PR79977.  */
+  if (loop_outer (entry->src->loop_father))
+    {
+      vec<edge> exits = get_loop_exit_edges (entry->src->loop_father);
+      for (unsigned i = 0; i < exits.length (); ++i)
+	{
+	  if (exits[i] != exit
+	      && bb_in_region (exits[i]->src, entry->dest, exit->src))
+	    {
+	      DEBUG_PRINT (dp << "[scop-detection-fail] cannot merge seses.\n");
+	      exits.release ();
+	      return invalid_sese;
+	    }
+	}
+      exits.release ();
+    }
+
   /* For now we just want to bail out when exit does not post-dominate entry.
      TODO: We might just add a basic_block at the exit to make exit
      post-dominate entry (the entire region).  */

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2017-03-09  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/79977
+	* gcc.dg/graphite/pr79977.c: New testcase.
+
 2017-03-09  Toma Tabacu  <toma.tabacu@imgtec.com>
 
 	* g++.dg/lto/pr69589_0.C: Add dg-require-effective-target for

gcc/testsuite/gcc.dg/graphite/pr79977.c

@@ -0,0 +1,27 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -floop-nest-optimize" } */
+
+int uo[3];
+int di;
+
+void
+i7 (int mp)
+{
+  int l4;
+
+wh:
+  while (l4 > 1)
+    {
+      for (di = 0; di < 2; ++di)
+	uo[di] = 0;
+
+      for (di = 0; di < 3; ++di)
+	{
+	  uo[di] = 0;
+	  if (mp != 0)
+	    goto wh;
+	}
+
+      --l4;
+    }
+}