On March 26, 2015 6:01:21 PM GMT+01:00, Jan Hubicka <hubi...@ucw.cz> wrote:
>Hi,
>this is updated patch I am testing (along with the fixes to verifiew
>and
>inliner I will commit independently).
OK.
Thanks,
Richard.
> * passes.def: Add pass_nothrow.
> * ipa-pure-const.c: (pass_data_nothrow): New.
> (pass_nothrow): New.
> (pass_nothrow::execute): New.
> (make_pass_nothrow): New.
> * tree-pass.h (make_pass_nothrow): Declare.
>Index: passes.def
>===================================================================
>--- passes.def (revision 221682)
>+++ passes.def (working copy)
>@@ -58,6 +58,7 @@ along with GCC; see the file COPYING3.
> NEXT_PASS (pass_build_ssa);
> NEXT_PASS (pass_ubsan);
> NEXT_PASS (pass_early_warn_uninitialized);
>+ NEXT_PASS (pass_nothrow);
> POP_INSERT_PASSES ()
>
> NEXT_PASS (pass_chkp_instrumentation_passes);
>Index: tree-pass.h
>===================================================================
>--- tree-pass.h (revision 221682)
>+++ tree-pass.h (working copy)
>@@ -436,6 +436,7 @@ extern gimple_opt_pass *make_pass_remove
> *ctxt);
>extern gimple_opt_pass *make_pass_build_cgraph_edges (gcc::context
>*ctxt);
>extern gimple_opt_pass *make_pass_local_pure_const (gcc::context
>*ctxt);
>+extern gimple_opt_pass *make_pass_nothrow (gcc::context *ctxt);
> extern gimple_opt_pass *make_pass_tracer (gcc::context *ctxt);
>extern gimple_opt_pass *make_pass_warn_unused_result (gcc::context
>*ctxt);
>extern gimple_opt_pass *make_pass_diagnose_tm_blocks (gcc::context
>*ctxt);
>Index: ipa-pure-const.c
>===================================================================
>--- ipa-pure-const.c (revision 221682)
>+++ ipa-pure-const.c (working copy)
>@@ -710,6 +711,16 @@ check_stmt (gimple_stmt_iterator *gsip,
> if (is_gimple_debug (stmt))
> return;
>
>+ /* Do consider clobber as side effects before IPA, so we rather
>inline
>+ C++ destructors and keep clobber semantics than eliminate them.
>+
>+ TODO: We may get smarter during early optimizations on these and
>let
>+ functions containing only clobbers to be optimized more. This is
>a common
>+ case of C++ destructors. */
>+
>+ if ((ipa || cfun->after_inlining) && gimple_clobber_p (stmt))
>+ return;
>+
> if (dump_file)
> {
> fprintf (dump_file, " scanning: ");
>@@ -1870,3 +1881,93 @@ make_pass_warn_function_noreturn (gcc::c
> {
> return new pass_warn_function_noreturn (ctxt);
> }
>+
>+/* Simple local pass for pure const discovery reusing the analysis
>from
>+ ipa_pure_const. This pass is effective when executed together
>with
>+ other optimization passes in early optimization pass queue. */
>+
>+namespace {
>+
>+const pass_data pass_data_nothrow =
>+{
>+ GIMPLE_PASS, /* type */
>+ "nothrow", /* name */
>+ OPTGROUP_NONE, /* optinfo_flags */
>+ TV_IPA_PURE_CONST, /* tv_id */
>+ 0, /* properties_required */
>+ 0, /* properties_provided */
>+ 0, /* properties_destroyed */
>+ 0, /* todo_flags_start */
>+ 0, /* todo_flags_finish */
>+};
>+
>+class pass_nothrow : public gimple_opt_pass
>+{
>+public:
>+ pass_nothrow (gcc::context *ctxt)
>+ : gimple_opt_pass (pass_data_nothrow, ctxt)
>+ {}
>+
>+ /* opt_pass methods: */
>+ opt_pass * clone () { return new pass_nothrow (m_ctxt); }
>+ virtual bool gate (function *) { return optimize; }
>+ virtual unsigned int execute (function *);
>+
>+}; // class pass_nothrow
>+
>+unsigned int
>+pass_nothrow::execute (function *)
>+{
>+ struct cgraph_node *node;
>+ basic_block this_block;
>+
>+ if (TREE_NOTHROW (current_function_decl))
>+ return 0;
>+
>+ node = cgraph_node::get (current_function_decl);
>+
>+ /* We run during lowering, we can not really use availability yet.
>*/
>+ if (cgraph_node::get (current_function_decl)->get_availability ()
>+ <= AVAIL_INTERPOSABLE)
>+ {
>+ if (dump_file)
>+ fprintf (dump_file, "Function is interposable;"
>+ " not analyzing.\n");
>+ return true;
>+ }
>+
>+ FOR_EACH_BB_FN (this_block, cfun)
>+ {
>+ gimple_stmt_iterator gsi;
>+ for (gsi = gsi_start_bb (this_block);
>+ !gsi_end_p (gsi);
>+ gsi_next (&gsi))
>+ if (stmt_can_throw_external (gsi_stmt (gsi)))
>+ {
>+ tree callee_t = gimple_call_fndecl (gsi_stmt (gsi));
>+ if (callee_t && recursive_call_p (current_function_decl,
>callee_t))
>+ continue;
>+
>+ if (dump_file)
>+ {
>+ fprintf (dump_file, "Statement can throw: ");
>+ print_gimple_stmt (dump_file, gsi_stmt (gsi), 0, 0);
>+ }
>+ return 0;
>+ }
>+ }
>+
>+ node->set_nothrow_flag (true);
>+ if (dump_file)
>+ fprintf (dump_file, "Function found to be nothrow: %s\n",
>+ current_function_name ());
>+ return 0;
>+}
>+
>+} // anon namespace
>+
>+gimple_opt_pass *
>+make_pass_nothrow (gcc::context *ctxt)
>+{
>+ return new pass_nothrow (ctxt);
>+}
