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-rw-r--r--gcc/loop-init.c35
1 files changed, 35 insertions, 0 deletions
diff --git a/gcc/loop-init.c b/gcc/loop-init.c
index 26c953f..e3734ab 100644
--- a/gcc/loop-init.c
+++ b/gcc/loop-init.c
@@ -245,6 +245,12 @@ fix_loop_structure (bitmap changed_bbs)
}
/* Remove the loop. */
+#ifdef ENABLE_CHECKING
+ if (loop->header)
+ loop->former_header = loop->header;
+ else
+ gcc_assert (loop->former_header != NULL);
+#endif
loop->header = NULL;
flow_loop_tree_node_remove (loop);
}
@@ -272,6 +278,35 @@ fix_loop_structure (bitmap changed_bbs)
FOR_EACH_VEC_ELT (*get_loops (cfun), i, loop)
if (loop && loop->header == NULL)
{
+#ifdef ENABLE_CHECKING
+ if (dump_file
+ && ((unsigned) loop->former_header->index
+ < basic_block_info_for_fn (cfun)->length ()))
+ {
+ basic_block former_header
+ = BASIC_BLOCK_FOR_FN (cfun, loop->former_header->index);
+ /* If the old header still exists we want to check if the
+ original loop is re-discovered or the old header is now
+ part of a newly discovered loop.
+ In both cases we should have avoided removing the loop. */
+ if (former_header == loop->former_header)
+ {
+ if (former_header->loop_father->header == former_header)
+ fprintf (dump_file, "fix_loop_structure: rediscovered "
+ "removed loop %d as loop %d with old header %d\n",
+ loop->num, former_header->loop_father->num,
+ former_header->index);
+ else if ((unsigned) former_header->loop_father->num
+ >= old_nloops)
+ fprintf (dump_file, "fix_loop_structure: header %d of "
+ "removed loop %d is part of the newly "
+ "discovered loop %d with header %d\n",
+ former_header->index, loop->num,
+ former_header->loop_father->num,
+ former_header->loop_father->header->index);
+ }
+ }
+#endif
(*get_loops (cfun))[i] = NULL;
flow_loop_free (loop);
}