[gcc r13-3003] Minor cleanup/prep in DOM

[Jeff Law <law@gcc.gnu.org>]

https://gcc.gnu.org/g:89b5a316cffa4a9fa2504e776a4cdc2ef492f00b

commit r13-3003-g89b5a316cffa4a9fa2504e776a4cdc2ef492f00b
Author: Jeff Law <jeffreyalaw@gmail.com>
Date:   Fri Sep 30 18:59:24 2022 -0400

    Minor cleanup/prep in DOM
    
    It's a bit weird that free_dom_edge_info leaves a dangling pointer in e->aux.
    Not sure what I was thinking.
    
    There's two callers.  One wipes e->aux immediately after the call, the other
    attaches a newly created object immediately after the call.  So we can wipe
    e->aux within the call and simplify one of the two call sites.
    
    This is preparatory work for a minor optimization where we want to detect
    another class of edge equivalences in DOM (until something better is available)
    and either attach them an existing edge_info structure or create a new one if
    one doesn't currently exist for a given edge.
    
    gcc/
            * tree-ssa-dom.cc (free_dom_edge_info): Clear e->aux too.
            (free_all_edge_infos): Do not clear e->aux here.

Diff:
---
 gcc/tree-ssa-dom.cc | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/gcc/tree-ssa-dom.cc b/gcc/tree-ssa-dom.cc
index 84bef798f52..fa43dbe6c44 100644
--- a/gcc/tree-ssa-dom.cc
+++ b/gcc/tree-ssa-dom.cc
@@ -393,7 +393,8 @@ edge_info::record_simple_equiv (tree lhs, tree rhs)
     simple_equivalences.safe_push (equiv_pair (lhs, rhs));
 }
 
-/* Free the edge_info data attached to E, if it exists.  */
+/* Free the edge_info data attached to E, if it exists and
+   clear e->aux.  */
 
 void
 free_dom_edge_info (edge e)
@@ -402,6 +403,7 @@ free_dom_edge_info (edge e)
 
   if (edge_info)
     delete edge_info;
+  e->aux = NULL;
 }
 
 /* Free all EDGE_INFO structures associated with edges in the CFG.
@@ -420,10 +422,7 @@ free_all_edge_infos (void)
   FOR_EACH_BB_FN (bb, cfun)
     {
       FOR_EACH_EDGE (e, ei, bb->preds)
-        {
-	  free_dom_edge_info (e);
-	  e->aux = NULL;
-	}
+	free_dom_edge_info (e);
     }
 }