[PATCH] Fix PR80764

[Richard Biener]

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

Richard.

2017-05-19  Richard Biener  <rguent...@suse.de>

        PR middle-end/80764
        * cfgexpand.c (expand_gimple_cond): Fix loop fixup.

        * gcc.dg/torture/pr80764.c: New testcase.

Index: gcc/cfgexpand.c
===================================================================
--- gcc/cfgexpand.c     (revision 248094)
+++ gcc/cfgexpand.c     (working copy)
@@ -2503,7 +2503,10 @@ 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, bb->loop_father);
+  add_bb_to_loop (new_bb, dest->loop_father);
+  if (bb->loop_father->latch == bb
+      && bb->loop_father->header == dest)
+    bb->loop_father->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/pr80764.c
===================================================================
--- gcc/testsuite/gcc.dg/torture/pr80764.c      (nonexistent)
+++ gcc/testsuite/gcc.dg/torture/pr80764.c      (working copy)
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+
+int b, d, f, h;
+char e;
+int fn1();
+int main() { return fn1(); }
+int fn1(int p1) {
+    for (; d;)
+      for (; e < 3;) {
+         for (; h;)
+           b = fn1(0);
+         return f;
+      }
+}