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.
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)
{
- 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
