On Tue, Feb 26, 2019 at 04:08:21PM +0100, Richard Biener wrote:
> I think we can have multiple .ABNORMAL_DISPATCHERs - at least in theory
> via inlining, though I see code in the inliner avoiding multiple ones
> at least for nonlocal goto, not sure if that covers all cases.
Ok.
> > Shall I modify the patch for that?
>
> Might it even simplify the patch? If not the only comment on the
> original patch is that it would be nice to test it on a SJLJ EH
> target ...
1 file changed, 29 insertions(+), 16 deletions(-)
so not really simplify it, but not terrible either.
Here is the incremental (untested) diff of what handles that.
I don't have access to any standard SJLJ EH targets, but will try
--enable-sjlj-exceptions on x86_64-linux to see how far I get with that.
--- gcc/tree-cfgcleanup.c.jj 2019-02-26 16:52:33.828719803 +0100
+++ gcc/tree-cfgcleanup.c 2019-02-26 17:11:07.735576027 +0100
@@ -731,12 +731,7 @@ cleanup_tree_cfg_bb (basic_block bb)
normally are effectively unreachable as well. Additionally ignore
__builtin_setjmp_receiver starting blocks, which have one FORCED_LABEL
and which are always only reachable through EDGE_ABNORMAL edge. They are
- handled in cleanup_control_flow_pre.
- Similarly, return true for EDGE_ABNORMAL edge from any basic block to
- .ABNORMAL_DISPATCHER basic block if the latter block has no successors.
- .ABNORMAL_DISPATCHER basic blocks that don't dispatch to anything are dead,
- don't really need any EDGE_ABNORMAL edges to them and can be safely
- removed. */
+ handled in cleanup_control_flow_pre. */
static bool
maybe_dead_abnormal_edge_p (edge e)
@@ -747,16 +742,7 @@ maybe_dead_abnormal_edge_p (edge e)
gimple_stmt_iterator gsi = gsi_start_nondebug_after_labels_bb (e->src);
gimple *g = gsi_stmt (gsi);
if (!g || !gimple_call_internal_p (g, IFN_ABNORMAL_DISPATCHER))
- {
- if (EDGE_COUNT (e->dest->succs) == 0)
- {
- gsi = gsi_start_nondebug_after_labels_bb (e->dest);
- g = gsi_stmt (gsi);
- if (g && gimple_call_internal_p (g, IFN_ABNORMAL_DISPATCHER))
- return true;
- }
- return false;
- }
+ return false;
tree target = NULL_TREE;
for (gsi = gsi_start_bb (e->dest); !gsi_end_p (gsi); gsi_next (&gsi))
@@ -846,6 +832,7 @@ cleanup_control_flow_pre ()
bitmap_clear (visited);
vec<edge, va_gc> *setjmp_vec = NULL;
+ auto_vec<basic_block, 4> abnormal_dispatchers;
stack.quick_push (ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs));
@@ -877,6 +864,16 @@ cleanup_control_flow_pre ()
stack.quick_push (ei_start (setjmp_vec));
}
+ if ((ei_edge (ei)->flags
+ & (EDGE_ABNORMAL | EDGE_EH)) == EDGE_ABNORMAL)
+ {
+ gimple_stmt_iterator gsi
+ = gsi_start_nondebug_after_labels_bb (dest);
+ gimple *g = gsi_stmt (gsi);
+ if (g && gimple_call_internal_p (g, IFN_ABNORMAL_DISPATCHER))
+ abnormal_dispatchers.safe_push (dest);
+ }
+
if (EDGE_COUNT (dest->succs) > 0)
stack.quick_push (ei_start (dest->succs));
}
@@ -895,6 +892,22 @@ cleanup_control_flow_pre ()
vec_free (setjmp_vec);
+ /* If we've marked .ABNORMAL_DISPATCHER basic block(s) as visited
+ above, but haven't marked any of their successors as visited,
+ unmark them now, so that they can be removed as useless. */
+ basic_block dispatcher_bb;
+ unsigned int k;
+ FOR_EACH_VEC_ELT (abnormal_dispatchers, k, dispatcher_bb)
+ {
+ edge e;
+ edge_iterator ei;
+ FOR_EACH_EDGE (e, ei, dispatcher_bb->succs)
+ if (bitmap_bit_p (visited, e->dest->index))
+ break;
+ if (e == NULL)
+ bitmap_clear_bit (visited, dispatcher_bb->index);
+ }
+
set_dom_info_availability (CDI_DOMINATORS, saved_state);
/* We are deleting BBs in non-reverse dominator order, make sure
Jakub
