[PATCH] Fix PR80901

[Richard Biener]

Third time's a charm.

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

Richard.

2017-05-30  Richard Biener  <rguent...@suse.de>

        PR middle-end/80901
        * cfgexpand.c (expand_gimple_cond): Match up loop fixup with
        split_edge code.

        * gcc.dg/torture/pr80901.c: New testcase.

Index: gcc/cfgexpand.c
===================================================================
--- gcc/cfgexpand.c     (revision 248634)
+++ gcc/cfgexpand.c     (working copy)
@@ -2503,10 +2503,11 @@ expand_gimple_cond (basic_block bb, gcon
   false_edge->flags |= EDGE_FALLTHRU;
   new_bb->count = false_edge->count;
   new_bb->frequency = EDGE_FREQUENCY (false_edge);
-  add_bb_to_loop (new_bb, dest->loop_father);
-  if (dest->loop_father->latch == bb
-      && dest->loop_father->header == dest)
-    dest->loop_father->latch = new_bb;
+  loop_p loop = find_common_loop (bb->loop_father, dest->loop_father);
+  add_bb_to_loop (new_bb, loop);
+  if (loop->latch == bb
+      && loop->header == dest)
+    loop->latch = new_bb;
   new_edge = make_edge (new_bb, dest, 0);
   new_edge->probability = REG_BR_PROB_BASE;
   new_edge->count = new_bb->count;
Index: gcc/testsuite/gcc.dg/torture/pr80901.c
===================================================================
--- gcc/testsuite/gcc.dg/torture/pr80901.c      (nonexistent)
+++ gcc/testsuite/gcc.dg/torture/pr80901.c      (working copy)
@@ -0,0 +1,32 @@
+/* { dg-do compile } */
+
+int a, b, c, d;
+
+int fn1 ()
+{
+  int f;
+  if (d)
+    while (c)
+      {
+       for (f = 0; f < 1; f++)
+         {
+           int g[70] = { 0 };
+           if (b)
+             ;
+           else
+             {
+               int h = !b;
+               for (; h; h = 1)
+                 ;
+             }
+         }
+       return 0;
+      }
+  return a;
+}
+
+int main ()
+{
+  fn1 ();
+  return 0;
+}