Hi,
In split_function() (ipa-split.c), for the newly created call stmt,
its block is set to the outermost scope, i.e.
DECL_INITIAL(current_function_decl). When we inline this
partially outlined function, we create the new block based on the
block for the call stmt (in expand_call_inline()).
So the new block for the inlined body is in
parallel to the function top level scope. This bad block structure will
late result in a bad stack layout.
This patch fixes the issue by setting the correct block number. It
starts with the split_point entry bb to find the block stmt in the
outlined region. The entry_bb maybe an empty BB so we need to follow
the CFG until we find a non-empty bb.
My early patch tried to use the block info from the first non-empty
bb in the outlined regision. But that failed bootstrap as some of the
stmts (assignment stmt) do not have the block info (bug?). So in this
patch I traverse all the stmts in the bb until getting the block info.
Tested with gcc bootstap.
Thanks,
2012-04-24 Rong Xu <x...@google.com>
* ipa-split.c (split_function): set the correct block for the
call statement.
Index: ipa-split.c
===================================================================
--- ipa-split.c (revision 186634)
+++ ipa-split.c (working copy)
@@ -948,7 +948,7 @@
int num = 0;
struct cgraph_node *node, *cur_node = cgraph_node (current_function_decl);
basic_block return_bb = find_return_bb ();
- basic_block call_bb;
+ basic_block call_bb, bb;
gimple_stmt_iterator gsi;
gimple call;
edge e;
@@ -958,6 +958,7 @@
gimple last_stmt = NULL;
unsigned int i;
tree arg;
+ tree split_loc_block = NULL;
if (dump_file)
{
@@ -1072,6 +1073,33 @@
}
}
+ /* Find the block location of the split region. */
+ bb = split_point->entry_bb;
+ do
+ {
+ bool found = false;
+
+ for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+ {
+ if (is_gimple_debug(gsi_stmt(gsi)))
+ continue;
+ if ((split_loc_block = gimple_block (gsi_stmt (gsi))))
+ {
+ found = true;
+ break;
+ }
+ }
+ if (found)
+ break;
+
+ /* If we reach here, this bb should be an empty unconditional
+ or fall-throuth branch. We continue with the succ bb. */
+ bb = single_succ (bb);
+ }
+ while (bb && bitmap_bit_p (split_point->split_bbs, bb->index));
+
+ gcc_assert (split_loc_block);
+
/* Now create the actual clone. */
rebuild_cgraph_edges ();
node = cgraph_function_versioning (cur_node, NULL, NULL, args_to_skip,
@@ -1115,7 +1143,7 @@
VEC_replace (tree, args_to_pass, i, arg);
}
call = gimple_build_call_vec (node->decl, args_to_pass);
- gimple_set_block (call, DECL_INITIAL (current_function_decl));
+ gimple_set_block (call, split_loc_block);
/* We avoid address being taken on any variable used by split part,
so return slot optimization is always possible. Moreover this is
--
This patch is available for review at http://codereview.appspot.com/6111050
