Hi!
As discussed in the PR, for functions that return an aggregate that is not
aggregate_value_p (i.e. returned in registers), using RESULT_DECL is
undesirable, that's not what we normally emit for user code.
So, this patch instead uses a temporary, which is optimized right now as
much as similar user written code.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2015-02-06 Jakub Jelinek <ja...@redhat.com>
PR ipa/64896
* cgraphunit.c (cgraph_node::expand_thunk): If
restype is not is_gimple_reg_type nor the thunk_fndecl
returns aggregate_value_p, set restmp to a temporary variable
instead of resdecl.
* g++.dg/ipa/pr64896.C: New test.
--- gcc/cgraphunit.c.jj 2015-01-29 21:38:21.000000000 +0100
+++ gcc/cgraphunit.c 2015-02-06 13:18:44.870527405 +0100
@@ -1609,11 +1609,16 @@ cgraph_node::expand_thunk (bool output_a
}
else if (!is_gimple_reg_type (restype))
{
- restmp = resdecl;
+ if (aggregate_value_p (resdecl, TREE_TYPE (thunk_fndecl)))
+ {
+ restmp = resdecl;
- if (TREE_CODE (restmp) == VAR_DECL)
- add_local_decl (cfun, restmp);
- BLOCK_VARS (DECL_INITIAL (current_function_decl)) = restmp;
+ if (TREE_CODE (restmp) == VAR_DECL)
+ add_local_decl (cfun, restmp);
+ BLOCK_VARS (DECL_INITIAL (current_function_decl)) = restmp;
+ }
+ else
+ restmp = create_tmp_var (restype, "retval");
}
else
restmp = create_tmp_reg (restype, "retval");
--- gcc/testsuite/g++.dg/ipa/pr64896.C.jj 2015-02-06 13:36:30.076680258
+0100
+++ gcc/testsuite/g++.dg/ipa/pr64896.C 2015-02-06 13:36:13.000000000 +0100
@@ -0,0 +1,29 @@
+// PR ipa/64896
+// { dg-do compile }
+// { dg-options "-O2" }
+
+struct A { int a, b; };
+struct B { A c; int d; };
+struct C { virtual B fn1 () const; };
+struct D { B fn2 () const; int fn3 () const; C *fn4 () const; };
+
+int
+D::fn3 () const
+{
+ fn4 ()->fn1 ();
+}
+
+B
+D::fn2 () const
+{
+ return B ();
+}
+
+class F : C
+{
+ B
+ fn1 () const
+ {
+ return B ();
+ }
+};
Jakub
