re PR tree-optimization/87895 (ICE in purge_dead_edges, at cfgrtl.c:3246)

	PR tree-optimization/87895
	* omp-simd-clone.c (ipa_simd_modify_function_body): When removing
	or replacing GIMPLE_RETURN, set EDGE_FALLTHRU on the edge to EXIT.
	(simd_clone_adjust): Don't set EDGE_FALLTHRU here. In a loop that
	redirects edges to EXIT to edges to incr_bb, iterate while EXIT
	has any preds and always use EDGE_PRED (, 0).

	* gcc.dg/gomp/pr87895-1.c: New test.
	* gcc.dg/gomp/pr87895-2.c: New test.
	* gcc.dg/gomp/pr87895-3.c: New test.

From-SVN: r266328

gcc/ChangeLog

+2018-11-20  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/87895
+	* omp-simd-clone.c (ipa_simd_modify_function_body): When removing
+	or replacing GIMPLE_RETURN, set EDGE_FALLTHRU on the edge to EXIT.
+	(simd_clone_adjust): Don't set EDGE_FALLTHRU here. In a loop that
+	redirects edges to EXIT to edges to incr_bb, iterate while EXIT
+	has any preds and always use EDGE_PRED (, 0).
+
 2018-11-20  Uros Bizjak  <ubizjak@gmail.com>
 
 	PR target/88070

gcc/omp-simd-clone.c

@@ -994,6 +994,8 @@ ipa_simd_modify_function_body (struct cgraph_node *node,
 	  if (greturn *return_stmt = dyn_cast <greturn *> (stmt))
 	    {
 	      tree retval = gimple_return_retval (return_stmt);
+	      edge e = find_edge (bb, EXIT_BLOCK_PTR_FOR_FN (cfun));
+	      e->flags |= EDGE_FALLTHRU;
 	      if (!retval)
 		{
 		  gsi_remove (&gsi, true);
@@ -1150,14 +1152,9 @@ simd_clone_adjust (struct cgraph_node *node)
       incr_bb = create_empty_bb (orig_exit);
       incr_bb->count = profile_count::zero ();
       add_bb_to_loop (incr_bb, body_bb->loop_father);
-      /* The succ of orig_exit was EXIT_BLOCK_PTR_FOR_FN (cfun), with an empty
-	 flag.  Set it now to be a FALLTHRU_EDGE.  */
-      gcc_assert (EDGE_COUNT (orig_exit->succs) == 1);
-      EDGE_SUCC (orig_exit, 0)->flags |= EDGE_FALLTHRU;
-      for (unsigned i = 0;
-	   i < EDGE_COUNT (EXIT_BLOCK_PTR_FOR_FN (cfun)->preds); ++i)
+      while (EDGE_COUNT (EXIT_BLOCK_PTR_FOR_FN (cfun)->preds))
 	{
-	  edge e = EDGE_PRED (EXIT_BLOCK_PTR_FOR_FN (cfun), i);
+	  edge e = EDGE_PRED (EXIT_BLOCK_PTR_FOR_FN (cfun), 0);
 	  redirect_edge_succ (e, incr_bb);
 	  incr_bb->count += e->count ();
 	}

gcc/testsuite/ChangeLog

+2018-11-20  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/87895
+	* gcc.dg/gomp/pr87895-1.c: New test.
+	* gcc.dg/gomp/pr87895-2.c: New test.
+	* gcc.dg/gomp/pr87895-3.c: New test.
+
 2018-11-20  Uros Bizjak  <ubizjak@gmail.com>
 
 	PR target/88070

gcc/testsuite/gcc.dg/gomp/pr87895-1.c

+/* PR tree-optimization/87895 */
+/* { dg-do compile } */
+/* { dg-additional-options "-O0" } */
+
+#pragma omp declare simd
+int
+foo (int x)
+{
+  if (x == 0)
+    return 0;
+}
+
+#pragma omp declare simd
+int
+bar (int *x, int y)
+{
+  if ((y == 0) ? (*x = 0) : *x)
+    return 0;
+}

gcc/testsuite/gcc.dg/gomp/pr87895-2.c

+/* PR tree-optimization/87895 */
+/* { dg-do compile } */
+/* { dg-additional-options "-O1" } */
+
+#include "pr87895-1.c"

gcc/testsuite/gcc.dg/gomp/pr87895-3.c

+/* PR tree-optimization/87895 */
+/* { dg-do compile } */
+/* { dg-additional-options "-O2" } */
+
+#pragma omp declare simd
+int foo (int x) __attribute__((noreturn));
+
+#pragma omp declare simd
+int
+bar (int x, int y)
+{
+  if (y == 1)
+    foo (x + 2);
+  if (y == 10)
+    foo (x + 6);
+  if (y != 25)
+    return 4;
+}