On Wed, 8 Jan 2014, Jakub Jelinek wrote:
> On Wed, Jan 08, 2014 at 12:19:02PM +0100, Richard Biener wrote:
> > On Wed, 8 Jan 2014, Jakub Jelinek wrote:
> >
> > > On Wed, Jan 08, 2014 at 12:15:40PM +0100, Richard Biener wrote:
> > > > > I start to think this is a too complex transform for stmt folding ...
> > > >
> > > > Alternatively do update_call_from_tree (gsi,
> > > > get_or_create_ssa_default_def
> > > > (cfun, create_tmp_var (TREE_TYPE (lhs)))).
> > >
> > > The lhs might not be is_gimple_reg_type though. What to do in that case?
> >
> > In that case you can remove the stmt.
>
> Ok, so like this? Unfortunately, I haven't been able to construct a
> testcase where this would be folded later than during gimplification where
> lhs is obviously not a SSA_NAME and we can safely replace the call.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux.
Ok, though if you are happy to do another change then ...
> 2014-01-08 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/59622
> * gimple-fold.c (gimple_fold_call): Fix a typo in message. Handle
> __cxa_pure_virtual similarly to __builtin_unreachable, but replace
> the OBJ_TYPE_REF call with the noreturn and add if needed a setter
> of the lhs SSA_NAME. Don't devirtualize for inplace at all.
>
> * g++.dg/opt/pr59622-2.C: New test.
> * g++.dg/opt/pr59622-3.C: New test.
> * g++.dg/opt/pr59622-4.C: New test.
>
> --- gcc/gimple-fold.c.jj 2014-01-08 10:23:24.536443566 +0100
> +++ gcc/gimple-fold.c 2014-01-08 17:02:40.356635177 +0100
> @@ -1167,7 +1167,7 @@ gimple_fold_call (gimple_stmt_iterator *
> (OBJ_TYPE_REF_EXPR
> (callee)))))
> {
> fprintf (dump_file,
> - "Type inheritnace inconsistent devirtualization of ");
> + "Type inheritance inconsistent devirtualization of ");
> print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
> fprintf (dump_file, " to ");
> print_generic_expr (dump_file, callee, TDF_SLIM);
> @@ -1177,26 +1177,46 @@ gimple_fold_call (gimple_stmt_iterator *
> gimple_call_set_fn (stmt, OBJ_TYPE_REF_EXPR (callee));
> changed = true;
> }
> - else if (flag_devirtualize && virtual_method_call_p (callee))
> + else if (flag_devirtualize && !inplace && virtual_method_call_p
> (callee))
> {
> bool final;
> vec <cgraph_node *>targets
> = possible_polymorphic_call_targets (callee, &final);
> if (final && targets.length () <= 1)
> {
> + tree fndecl;
> if (targets.length () == 1)
> + fndecl = targets[0]->decl;
> + else
> + fndecl = builtin_decl_implicit (BUILT_IN_UNREACHABLE);
> +
> + /* If fndecl (like __builtin_unreachable or
> + __cxa_pure_virtual) takes no arguments, doesn't have
> + return value and is noreturn, if the call doesn't have
> + lhs or lhs isn't SSA_NAME, replace the call with
> + the noreturn call, otherwise insert it before the call
> + and replace the call with setting of lhs to default def. */
> + if (TREE_THIS_VOLATILE (fndecl)
> + && VOID_TYPE_P (TREE_TYPE (TREE_TYPE (fndecl)))
> + && TYPE_ARG_TYPES (TREE_TYPE (fndecl)) == void_list_node)
... restrict this to the targets.length () == 0 case.
Thanks,
Richard.
> {
> - gimple_call_set_fndecl (stmt, targets[0]->decl);
> - changed = true;
> - }
> - else if (!inplace)
> - {
> - tree fndecl = builtin_decl_implicit (BUILT_IN_UNREACHABLE);
> + tree lhs = gimple_call_lhs (stmt);
> gimple new_stmt = gimple_build_call (fndecl, 0);
> gimple_set_location (new_stmt, gimple_location (stmt));
> - gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT);
> + if (lhs && TREE_CODE (lhs) == SSA_NAME)
> + {
> + tree var = create_tmp_var (TREE_TYPE (lhs), NULL);
> + tree def = get_or_create_ssa_default_def (cfun, var);
> + gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT);
> + update_call_from_tree (gsi, def);
> + }
> + else
> + gsi_replace (gsi, new_stmt, true);
> return true;
> }
> +
> + gimple_call_set_fndecl (stmt, fndecl);
> + changed = true;
> }
> }
> }
> --- gcc/testsuite/g++.dg/opt/pr59622-2.C.jj 2014-01-08 16:42:49.588747876
> +0100
> +++ gcc/testsuite/g++.dg/opt/pr59622-2.C 2014-01-08 16:42:49.588747876
> +0100
> @@ -0,0 +1,21 @@
> +// PR tree-optimization/59622
> +// { dg-do compile }
> +// { dg-options "-O2" }
> +
> +namespace
> +{
> + struct A
> + {
> + A () {}
> + virtual A *bar (int) = 0;
> + A *baz (int x) { return bar (x); }
> + };
> +}
> +
> +A *a;
> +
> +void
> +foo ()
> +{
> + a->baz (0);
> +}
> --- gcc/testsuite/g++.dg/opt/pr59622-3.C.jj 2014-01-08 17:00:20.944359961
> +0100
> +++ gcc/testsuite/g++.dg/opt/pr59622-3.C 2014-01-08 17:00:44.558244745
> +0100
> @@ -0,0 +1,21 @@
> +// PR tree-optimization/59622
> +// { dg-do compile }
> +// { dg-options "-O2" }
> +
> +struct C { int a; int b; };
> +
> +namespace
> +{
> + struct A
> + {
> + virtual C foo ();
> + C bar () { return foo (); }
> + };
> +}
> +
> +C
> +baz ()
> +{
> + A a;
> + return a.bar ();
> +}
> --- gcc/testsuite/g++.dg/opt/pr59622-4.C.jj 2014-01-08 17:00:54.332188462
> +0100
> +++ gcc/testsuite/g++.dg/opt/pr59622-4.C 2014-01-08 17:01:41.113947431
> +0100
> @@ -0,0 +1,23 @@
> +// PR tree-optimization/59622
> +// { dg-do compile }
> +// { dg-options "-O2" }
> +
> +struct C { int a; int b; };
> +
> +namespace
> +{
> + struct A
> + {
> + A () {}
> + virtual C bar (int) = 0;
> + C baz (int x) { return bar (x); }
> + };
> +}
> +
> +A *a;
> +
> +C
> +foo ()
> +{
> + return a->baz (0);
> +}
>
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE / SUSE Labs
SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746
GF: Jeff Hawn, Jennifer Guild, Felix Imend"orffer
