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Re: [PATCH] [PR c++/85027] deal with baselink in save_expr in instantiate_type
- From: Jason Merrill <jason at redhat dot com>
- To: Alexandre Oliva <aoliva at redhat dot com>
- Cc: gcc-patches List <gcc-patches at gcc dot gnu dot org>, Nathan Sidwell <nathan at acm dot org>
- Date: Fri, 30 Mar 2018 10:48:56 -0400
- Subject: Re: [PATCH] [PR c++/85027] deal with baselink in save_expr in instantiate_type
- References: <or605e6m0n.fsf@lxoliva.fsfla.org>
OK.
On Fri, Mar 30, 2018 at 3:49 AM, Alexandre Oliva <aoliva@redhat.com> wrote:
> We use SAVE_EXPRs in conditional expressions without the middle
> operand, to evaluate the first operand only once. When the conversion
> of the first operand fails, we may call instantiate_type get a better
> error message. We have code to peel off the SAVE_EXPR there, but then
> we may end up with a BASELINK, and we're past the code that deals with
> BASELINKs. Reorder the tests so that we expose the saved expr first,
> and then deal with BASELINKs.
>
> Regstrapped on i686- and x86_64-linux-gnu. Ok to install?
>
> for gcc/cp/ChangeLog
>
> PR c++/85027
> * class.c (instantiate_type): Peel off SAVE_EXPR before
> BASELINK.
>
> for gcc/testsuite/ChangeLog
>
> PR c++/85027
> * g++.dg/pr85027.C: New.
> ---
> gcc/cp/class.c | 10 +++++-----
> gcc/testsuite/g++.dg/pr85027.C | 8 ++++++++
> 2 files changed, 13 insertions(+), 5 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/pr85027.C
>
> diff --git a/gcc/cp/class.c b/gcc/cp/class.c
> index debcaf21cf76..0427d1224f74 100644
> --- a/gcc/cp/class.c
> +++ b/gcc/cp/class.c
> @@ -7971,6 +7971,11 @@ instantiate_type (tree lhstype, tree rhs, tsubst_flags_t complain)
> }
> }
>
> + /* If we instantiate a template, and it is a A ?: C expression
> + with omitted B, look through the SAVE_EXPR. */
> + if (TREE_CODE (rhs) == SAVE_EXPR)
> + rhs = TREE_OPERAND (rhs, 0);
> +
> if (BASELINK_P (rhs))
> {
> access_path = BASELINK_ACCESS_BINFO (rhs);
> @@ -7986,11 +7991,6 @@ instantiate_type (tree lhstype, tree rhs, tsubst_flags_t complain)
> return error_mark_node;
> }
>
> - /* If we instantiate a template, and it is a A ?: C expression
> - with omitted B, look through the SAVE_EXPR. */
> - if (TREE_CODE (rhs) == SAVE_EXPR)
> - rhs = TREE_OPERAND (rhs, 0);
> -
> /* There are only a few kinds of expressions that may have a type
> dependent on overload resolution. */
> gcc_assert (TREE_CODE (rhs) == ADDR_EXPR
> diff --git a/gcc/testsuite/g++.dg/pr85027.C b/gcc/testsuite/g++.dg/pr85027.C
> new file mode 100644
> index 000000000000..01b1b291aecd
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/pr85027.C
> @@ -0,0 +1,8 @@
> +// { dg-do compile }
> +
> +// Avoid -pedantic-error default
> +// { dg-options "" }
> +
> +struct A { static int a; };
> +
> +int t = A::A ? : 0; // { dg-error "cannot resolve" }
>
>
> --
> Alexandre Oliva, freedom fighter http://FSFLA.org/~lxoliva/
> You must be the change you wish to see in the world. -- Gandhi
> Be Free! -- http://FSFLA.org/ FSF Latin America board member
> Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer