[PATCH] tree-optimization/103219 - avoid ICE in unroll-and-jam

[Richard Biener via Gcc-patches]

For no particularly good reason unroll-and-jam uses single_dom_exit
to determine the exit for the region it wants to run VN on.  That
happens to ICE because of the dominance restriction.  Use single_exit
instead.

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

2021-11-15  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/103219
        * gimple-loop-jam.c (tree_loop_unroll_and_jam): Use single_exit
        to determine the exit for the VN region.

        * gcc.dg/torture/pr103219.c: New testcase.
---
 gcc/gimple-loop-jam.c                   |  2 +-
 gcc/testsuite/gcc.dg/torture/pr103219.c | 24 ++++++++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.dg/torture/pr103219.c

diff --git a/gcc/gimple-loop-jam.c b/gcc/gimple-loop-jam.c
index 611d3805304..666f740f86d 100644
--- a/gcc/gimple-loop-jam.c
+++ b/gcc/gimple-loop-jam.c
@@ -593,7 +593,7 @@ tree_loop_unroll_and_jam (void)
          todo |= TODO_cleanup_cfg;
 
          auto_bitmap exit_bbs;
-         bitmap_set_bit (exit_bbs, single_dom_exit (outer)->dest->index);
+         bitmap_set_bit (exit_bbs, single_exit (outer)->dest->index);
          todo |= do_rpo_vn (cfun, loop_preheader_edge (outer), exit_bbs);
        }
 
diff --git a/gcc/testsuite/gcc.dg/torture/pr103219.c 
b/gcc/testsuite/gcc.dg/torture/pr103219.c
new file mode 100644
index 00000000000..cb9023ed8b6
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr103219.c
@@ -0,0 +1,24 @@
+/* { dg-do compile } */
+
+int f();
+void g();
+int a, b, c, e;
+int d[10];
+int main()
+{
+  if (c)
+    if (f())
+      {
+       g();
+       if (e) {
+           a = 0;
+           for (; a != 6; a = a + 2)
+             {
+               b = 0;
+               for (; b <= 3; b++)
+                 d[b] &= 1;
+             }
+       }
+      }
+  return 0;
+}
-- 
2.31.1