This function is used to determine whether a callback edge should be
kept or not. It was supposed to capture the idea that a callback edge
has been redirected at some point, however, it only considered
redirecting to some clone. However, an edge may not always be
redirected to a clone. For example, common function bodies produced by
icf are not clones. This version of the function captures this idea
better. If you know of a better way, please let me know.
gcc/ChangeLog:
* attr-callback.cc (callback_edge_useful_p): Rewrite the
heuristic, now consider icf bodies and not yet redirected
edges.
Signed-off-by: Josef Melcr <[email protected]>
---
gcc/attr-callback.cc | 21 ++++++++++++++++-----
1 file changed, 16 insertions(+), 5 deletions(-)
diff --git a/gcc/attr-callback.cc b/gcc/attr-callback.cc
index 83d27544150..4c4b695f5c7 100644
--- a/gcc/attr-callback.cc
+++ b/gcc/attr-callback.cc
@@ -344,11 +344,22 @@ bool
callback_edge_useful_p (cgraph_edge *e)
{
gcc_checking_assert (e->callback);
- /* If the edge is not pointing towards a clone, it is no longer useful as its
- entire purpose is to produce clones of callbacks. */
- if (!e->callee->clone_of)
- return false;
- return true;
+ /* If the edge is pointing towards a clone, it is useful. */
+ if (e->callee->clone_of)
+ return true;
+
+ /* If the callee has been produced by icf, the edge is useful, as it will be
+ used to for the redirection. */
+ if (e->callee->icf_merged)
+ return true;
+
+ /* If the decl in the call stmt doesn't match, the edge has been redirected
+ and thus is useful. */
+ if (e->call_stmt
+ && gimple_call_arg (e->call_stmt, e->callback_id) != e->callee->decl)
+ return true;
+
+ return false;
}
/* Returns the number of arguments the callback function described by ATTR
--
2.51.1.dirty
