This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: [PATCH] Fix thunk expansion (PR ipa/64896)
- From: Jan Hubicka <hubicka at ucw dot cz>
- To: Jakub Jelinek <jakub at redhat dot com>
- Cc: Jan Hubicka <hubicka at ucw dot cz>, Richard Biener <rguenther at suse dot de>, gcc-patches at gcc dot gnu dot org
- Date: Fri, 6 Feb 2015 21:37:09 +0100
- Subject: Re: [PATCH] Fix thunk expansion (PR ipa/64896)
- Authentication-results: sourceware.org; auth=none
- References: <20150206202331 dot GO1746 at tucnak dot redhat dot com>
> 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?
OK,
thanks!
Honza
>
> 2015-02-06 Jakub Jelinek <jakub@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