Le 18/09/2025 à 09:43, Richard Biener a écrit :
diff --git a/gcc/tree-ssa-pre.cc b/gcc/tree-ssa-pre.cc
index 99331730bc2..18b36259cb4 100644
--- a/gcc/tree-ssa-pre.cc
+++ b/gcc/tree-ssa-pre.cc
@@ -2118,6 +2121,20 @@ compute_antic_aux (basic_block block, bool
block_has_abnormal_pred_edge)
first = e;
else if (BB_VISITED (e->dest))
worklist.quick_push (e);
+ else if (0 && !(e->flags & EDGE_DFS_BACK))
This (dead) branch should probably be removed, was it really your intent
to add it?
+ {
+ /* When our reverse iteration order does not match up with
+ a forward DFS which can in happen with unfortunate
+ choices of fake edges to exits from infinite loops, we
+ have to avoid intermangling two ANTIC iterations by
+ using ANTIC_IN computed in the previous iteration.
+ As we cannot easily do this stabilize the iteration by
+ not allowing a MAX set on such edge initially. */
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "ANTIC_IN is uncomputed on non-DFS_BACK "
+ "%d->%d\n", e->src->index, e->dest->index);
+ worklist.quick_push (e);
+ }
else
{
/* Unvisited successors get their ANTIC_IN replaced by the
