On Wed, Apr 28, 2021 at 8:54 AM Andreas Krebbel via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> The problem appears to be triggered by two locations in the front-end
> where non-POINTER_SIZE pointers aren't handled right now.
>
> 1. An assertion in strip_typedefs is triggered because the alignment
> of the types don't match. This in turn is caused by creating the new
> type with build_pointer_type instead of taking the type of the
> original pointer into account.
>
> 2. An assertion in cp_convert_to_pointer is triggered which expects
> the target type to always have POINTER_SIZE.
>
> Ok for mainline?
>
> gcc/cp/ChangeLog:
>
> PR c++/100281
> * cvt.c (cp_convert_to_pointer): Use the size of the target
> pointer type.
> * tree.c (strip_typedefs): Use build_pointer_type_for_mode for
> non-POINTER_SIZE pointers.
>
> gcc/testsuite/ChangeLog:
>
> PR c++/100281
> * g++.target/s390/pr100281.C: New test.
> ---
> gcc/cp/cvt.c | 2 +-
> gcc/cp/tree.c | 5 ++++-
> gcc/testsuite/g++.target/s390/pr100281.C | 10 ++++++++++
> 3 files changed, 15 insertions(+), 2 deletions(-)
> create mode 100644 gcc/testsuite/g++.target/s390/pr100281.C
>
> diff --git a/gcc/cp/cvt.c b/gcc/cp/cvt.c
> index f1687e804d1..7fa6e8df52b 100644
> --- a/gcc/cp/cvt.c
> +++ b/gcc/cp/cvt.c
> @@ -232,7 +232,7 @@ cp_convert_to_pointer (tree type, tree expr, bool dofold,
> {
> if (TYPE_PRECISION (intype) == POINTER_SIZE)
> return build1 (CONVERT_EXPR, type, expr);
> - expr = cp_convert (c_common_type_for_size (POINTER_SIZE, 0), expr,
> + expr = cp_convert (c_common_type_for_size (TYPE_PRECISION (type), 0),
> expr,
> complain);
> /* Modes may be different but sizes should be the same. There
> is supposed to be some integral type that is the same width
> diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
> index a8bfd5fc053..6f6b732c9c9 100644
> --- a/gcc/cp/tree.c
> +++ b/gcc/cp/tree.c
> @@ -1556,7 +1556,10 @@ strip_typedefs (tree t, bool *remove_attributes,
> unsigned int flags)
> {
> case POINTER_TYPE:
> type = strip_typedefs (TREE_TYPE (t), remove_attributes, flags);
> - result = build_pointer_type (type);
> + if (TYPE_PRECISION (t) == POINTER_SIZE)
> + result = build_pointer_type (type);
> + else
> + result = build_pointer_type_for_mode (type, TYPE_MODE (t), false);
I wonder under which circumstances re-using the original mode will fail? In
particular I do not like the TYPE_PRECISION check. Supposedly you
were thinking of playing safe?
> break;
> case REFERENCE_TYPE:
> type = strip_typedefs (TREE_TYPE (t), remove_attributes, flags);
There's code below with exactly the same issue for reference types which
would need adjustments to cp_build_reference_type.
> diff --git a/gcc/testsuite/g++.target/s390/pr100281.C
> b/gcc/testsuite/g++.target/s390/pr100281.C
> new file mode 100644
> index 00000000000..f45798c3879
> --- /dev/null
> +++ b/gcc/testsuite/g++.target/s390/pr100281.C
> @@ -0,0 +1,10 @@
> +// PR C++/100281
> +// { dg-do compile }
> +
> +typedef void * __attribute__((mode (SI))) __ptr32_t;
> +
> +void foo(){
> + unsigned int b = 100;
> + __ptr32_t a;
> + a = b; /* { dg-error "invalid conversion from 'unsigned int' to
> '__ptr32_t'.*" } */
> +}
> --
> 2.30.2
>
