[gcc r12-2680] tree-cfg: Fix typos on dloop in move_sese_region_to_fn

[gcc r12-2680] tree-cfg: Fix typos on dloop in move_sese_region_to_fn

[Kewen Lin]

https://gcc.gnu.org/g:daaed9e365a2b1371e30f619c7d9f19d1558a01b

commit r12-2680-gdaaed9e365a2b1371e30f619c7d9f19d1558a01b
Author: Kewen Lin <linkw@linux.ibm.com>
Date:   Mon Aug 2 22:12:00 2021 -0500

    tree-cfg: Fix typos on dloop in move_sese_region_to_fn
    
    As mentioned in [1], there is one pre-existing issue before
    the refactoring of FOR_EACH_LOOP_FN.  The macro will always
    set the given LOOP as NULL at the end of iterating unless
    there is some early break inside, obviously there is no
    early break and dloop will be set as NULL after the loop
    iterating.  It's kept as NULL after the factoring.
    
    I tried to debug the test case gcc.dg/graphite/pr83359.c
    with commit 555758de90074 (also reproduced the ICE with
    555758de90074~), and noticed the compilation of the test
    case only covers the hunk:
    
      else
        {
          moved_orig_loop_num[dloop->orig_loop_num] = -1;
          dloop->orig_loop_num = 0;
        }
    
    it doesn't touch the if condition hunk to increase
    "moved_orig_loop_num[dloop->orig_loop_num]".  So the
    following hunk guarded with
    
      if (moved_orig_loop_num[orig_loop_num] == 2)
    
    using dloop for dereference doesn't get executed.  It
    explains why the problem doesn't get exposed before.
    
    By looking to the code using dloop, I think it's a copy
    paste typo, the modified assertion codes have the same
    words as the above condition check.  In that context, the
    expected original number has been assigned to variable
    orig_loop_num by extracting from the arg0 of the call
    IFN_LOOP_DIST_ALIAS.
    
    [1] https://gcc.gnu.org/pipermail/gcc-patches/2021-July/576367.html
    
    gcc/ChangeLog:
    
            * tree-cfg.c (move_sese_region_to_fn): Fix typos on dloop.

Diff:
---
 gcc/tree-cfg.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/gcc/tree-cfg.c b/gcc/tree-cfg.c
index 48ee8c011ab..9883eaaa9bf 100644
--- a/gcc/tree-cfg.c
+++ b/gcc/tree-cfg.c
@@ -7747,9 +7747,8 @@ move_sese_region_to_fn (struct function *dest_cfun, basic_block entry_bb,
 
   /* Fix up orig_loop_num.  If the block referenced in it has been moved
      to dest_cfun, update orig_loop_num field, otherwise clear it.  */
-  class loop *dloop = NULL;
   signed char *moved_orig_loop_num = NULL;
-  for (class loop *dloop : loops_list (dest_cfun, 0))
+  for (auto dloop : loops_list (dest_cfun, 0))
     if (dloop->orig_loop_num)
       {
 	if (moved_orig_loop_num == NULL)
@@ -7787,11 +7786,10 @@ move_sese_region_to_fn (struct function *dest_cfun, basic_block entry_bb,
 	      /* If we have moved both loops with this orig_loop_num into
 		 dest_cfun and the LOOP_DIST_ALIAS call is being moved there
 		 too, update the first argument.  */
-	      gcc_assert ((*larray)[dloop->orig_loop_num] != NULL
-			  && (get_loop (saved_cfun, dloop->orig_loop_num)
-			      == NULL));
+	      gcc_assert ((*larray)[orig_loop_num] != NULL
+			  && (get_loop (saved_cfun, orig_loop_num) == NULL));
 	      tree t = build_int_cst (integer_type_node,
-				      (*larray)[dloop->orig_loop_num]->num);
+				      (*larray)[orig_loop_num]->num);
 	      gimple_call_set_arg (g, 0, t);
 	      update_stmt (g);
 	      /* Make sure the following loop will not update it.  */