| Message ID | 53A7BBDA.5010207@codesourcery.com |
|---|---|
| State | New |
| Headers | show |
On Mon, Jun 23, 2014 at 7:32 AM, Chung-Lin Tang <cltang@codesourcery.com> wrote: > Hi Richard, > > In this change: > https://gcc.gnu.org/ml/gcc-patches/2014-06/msg01278.html > > where substitute_and_fold() was changed to use a dom walker, the calls > to purge dead EH edges during the walk can alter the dom-tree, and have > chaotic results; the testcase in PR 61554 has some blocks traversed > twice during the walk, causing the segfault during CCP. > > The patch records the to-be-purged-for-dead-EH blocks in a similar > manner like stmts_to_remove, and processes it after the walk. (another > possible method would be using a bitmap to record the BBs + calling > gimple_purge_all_dead_eh_edges...) Oops. > Bootstrapped and tested on x86_64-linux, is this okay for trunk? Can you please use a bitmap and use gimple_purge_all_dead_eh_edges like tree-ssa-pre.c does? Also please add the reduced testcase from the PR to the g++.dg/torture Ok with that changes. Thanks, Richard. > Thanks, > Chung-Lin > > 2014-06-23 Chung-Lin Tang <cltang@codesourcery.com> > > PR tree-optimization/61554 > * tree-ssa-propagate.c (substitute_and_fold_dom_walker): > Add 'vec<basic_block> bbs_to_purge_dead_eh_edges' member, > properly update constructor/destructor. > (substitute_and_fold_dom_walker::before_dom_children): > Remove call to gimple_purge_dead_eh_edges, add bb to > bbs_to_purge_dead_eh_edges instead. > (substitute_and_fold): Call gimple_purge_dead_eh_edges for > bbs recorded in bbs_to_purge_dead_eh_edges.
Index: tree-ssa-propagate.c =================================================================== --- tree-ssa-propagate.c (revision 211874) +++ tree-ssa-propagate.c (working copy) @@ -1031,8 +1031,13 @@ class substitute_and_fold_dom_walker : public dom_ fold_fn (fold_fn_), do_dce (do_dce_), something_changed (false) { stmts_to_remove.create (0); + bbs_to_purge_dead_eh_edges.create (0); } - ~substitute_and_fold_dom_walker () { stmts_to_remove.release (); } + ~substitute_and_fold_dom_walker () + { + stmts_to_remove.release (); + bbs_to_purge_dead_eh_edges.release (); + } virtual void before_dom_children (basic_block); virtual void after_dom_children (basic_block) {} @@ -1042,6 +1047,7 @@ class substitute_and_fold_dom_walker : public dom_ bool do_dce; bool something_changed; vec<gimple> stmts_to_remove; + vec<basic_block> bbs_to_purge_dead_eh_edges; }; void @@ -1144,7 +1150,7 @@ substitute_and_fold_dom_walker::before_dom_childre /* If we cleaned up EH information from the statement, remove EH edges. */ if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt)) - gimple_purge_dead_eh_edges (bb); + bbs_to_purge_dead_eh_edges.safe_push (bb); if (is_gimple_assign (stmt) && (get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) @@ -1235,6 +1241,14 @@ substitute_and_fold (ssa_prop_get_value_fn get_val } } + while (!walker.bbs_to_purge_dead_eh_edges.is_empty ()) + { + basic_block bb = walker.bbs_to_purge_dead_eh_edges.pop (); + gimple_purge_dead_eh_edges (bb); + if (dump_file && dump_flags & TDF_DETAILS) + fprintf (dump_file, "Purge dead EH edges from bb %d\n", bb->index); + } + statistics_counter_event (cfun, "Constants propagated", prop_stats.num_const_prop); statistics_counter_event (cfun, "Copies propagated",