[PATCH] Fix PR92069

[Richard Biener]

This fixes the PR by not setting vect_nested_cycle on the latch def
for nested cycles.

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.

Richard.

2019-10-14  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/92069
        * tree-vect-loop.c (vect_analyze_scalar_cycles_1): For nested
        cycles do not set vect_nested_cycle on the latch definition.

        * gcc.dg/torture/pr92069.c: New testcase.

Index: gcc/tree-vect-loop.c
===================================================================
--- gcc/tree-vect-loop.c        (revision 276950)
+++ gcc/tree-vect-loop.c        (working copy)
@@ -584,7 +584,6 @@ vect_analyze_scalar_cycles_1 (loop_vec_i
                                     "Detected vectorizable nested cycle.\n");
 
                   STMT_VINFO_DEF_TYPE (stmt_vinfo) = vect_nested_cycle;
-                 STMT_VINFO_DEF_TYPE (reduc_stmt_info) = vect_nested_cycle;
                 }
               else
                 {
Index: gcc/testsuite/gcc.dg/torture/pr92069.c
===================================================================
--- gcc/testsuite/gcc.dg/torture/pr92069.c      (nonexistent)
+++ gcc/testsuite/gcc.dg/torture/pr92069.c      (working copy)
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-ftree-vectorize" } */
+
+unsigned int a, c, d;
+double b;
+void e()
+{
+  for (; d; d++)
+    {
+      double f;
+      a = 2;
+      for (; a; a++)
+       {
+         c = b;
+         b = f;
+         f = c;
+       }
+    }
+}