Re: [PATCH 1/1 v2] PR100281 C++: Fix SImode pointer handling

[Richard Biener <richard.guenther@gmail.com>]

On Thu, May 13, 2021 at 8:28 AM Andreas Krebbel via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> v1 -> v2: build_reference_type_for_mode and build_pointer_type_for_mode now pick pointer mode if
> MODE argument is VOIDmode.
>
> Bootstrapped and regression tested on x86_64 and s390x.
>
> Ok for mainline and GCC 11?

The middle-end parts are fine with me.

Richard.

> Andreas
>
>
> gcc/cp/ChangeLog:
>
>         PR c++/100281
>         * cvt.c (cp_convert_to_pointer): Use the size of the target
>         pointer type.
>         * tree.c (cp_build_reference_type): Call
>         cp_build_reference_type_for_mode with VOIDmode.
>         (cp_build_reference_type_for_mode): Rename from
>         cp_build_reference_type.  Add MODE argument and invoke
>         build_reference_type_for_mode.
>         (strip_typedefs): Use build_pointer_type_for_mode and
>         cp_build_reference_type_for_mode for pointers and references.
>
> gcc/ChangeLog:
>
>         PR c++/100281
>         * tree.c (build_reference_type_for_mode)
>         (build_pointer_type_for_mode): Pick pointer mode if MODE argument
>         is VOIDmode.
>         (build_reference_type, build_pointer_type): Invoke
>         build_*_type_for_mode with VOIDmode.
>
> gcc/testsuite/ChangeLog:
>
>         PR c++/100281
>         * g++.target/s390/pr100281-1.C: New test.
>         * g++.target/s390/pr100281-2.C: New test.
> ---
>  gcc/cp/cvt.c                               |  2 +-
>  gcc/cp/tree.c                              | 25 ++++++++++++++-----
>  gcc/testsuite/g++.target/s390/pr100281-1.C | 10 ++++++++
>  gcc/testsuite/g++.target/s390/pr100281-2.C |  9 +++++++
>  gcc/tree.c                                 | 29 ++++++++++++++--------
>  5 files changed, 57 insertions(+), 18 deletions(-)
>  create mode 100644 gcc/testsuite/g++.target/s390/pr100281-1.C
>  create mode 100644 gcc/testsuite/g++.target/s390/pr100281-2.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 7f148b4b158..35faeff065a 100644
> --- a/gcc/cp/tree.c
> +++ b/gcc/cp/tree.c
> @@ -1206,12 +1206,14 @@ vla_type_p (tree t)
>    return false;
>  }
>
> -/* Return a reference type node referring to TO_TYPE.  If RVAL is
> +
> +/* Return a reference type node of MODE referring to TO_TYPE.  If MODE
> +   is VOIDmode the standard pointer mode will be picked.  If RVAL is
>     true, return an rvalue reference type, otherwise return an lvalue
>     reference type.  If a type node exists, reuse it, otherwise create
>     a new one.  */
>  tree
> -cp_build_reference_type (tree to_type, bool rval)
> +cp_build_reference_type_for_mode (tree to_type, machine_mode mode, bool rval)
>  {
>    tree lvalue_ref, t;
>
> @@ -1224,7 +1226,8 @@ cp_build_reference_type (tree to_type, bool rval)
>        to_type = TREE_TYPE (to_type);
>      }
>
> -  lvalue_ref = build_reference_type (to_type);
> +  lvalue_ref = build_reference_type_for_mode (to_type, mode, false);
> +
>    if (!rval)
>      return lvalue_ref;
>
> @@ -1250,7 +1253,7 @@ cp_build_reference_type (tree to_type, bool rval)
>      SET_TYPE_STRUCTURAL_EQUALITY (t);
>    else if (TYPE_CANONICAL (to_type) != to_type)
>      TYPE_CANONICAL (t)
> -      = cp_build_reference_type (TYPE_CANONICAL (to_type), rval);
> +      = cp_build_reference_type_for_mode (TYPE_CANONICAL (to_type), mode, rval);
>    else
>      TYPE_CANONICAL (t) = t;
>
> @@ -1260,6 +1263,16 @@ cp_build_reference_type (tree to_type, bool rval)
>
>  }
>
> +/* Return a reference type node referring to TO_TYPE.  If RVAL is
> +   true, return an rvalue reference type, otherwise return an lvalue
> +   reference type.  If a type node exists, reuse it, otherwise create
> +   a new one.  */
> +tree
> +cp_build_reference_type (tree to_type, bool rval)
> +{
> +  return cp_build_reference_type_for_mode (to_type, VOIDmode, rval);
> +}
> +
>  /* Returns EXPR cast to rvalue reference type, like std::move.  */
>
>  tree
> @@ -1561,11 +1574,11 @@ 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);
> +      result = build_pointer_type_for_mode (type, TYPE_MODE (t), false);
>        break;
>      case REFERENCE_TYPE:
>        type = strip_typedefs (TREE_TYPE (t), remove_attributes, flags);
> -      result = cp_build_reference_type (type, TYPE_REF_IS_RVALUE (t));
> +      result = cp_build_reference_type_for_mode (type, TYPE_MODE (t), TYPE_REF_IS_RVALUE (t));
>        break;
>      case OFFSET_TYPE:
>        t0 = strip_typedefs (TYPE_OFFSET_BASETYPE (t), remove_attributes, flags);
> diff --git a/gcc/testsuite/g++.target/s390/pr100281-1.C b/gcc/testsuite/g++.target/s390/pr100281-1.C
> new file mode 100644
> index 00000000000..b82e27b64e9
> --- /dev/null
> +++ b/gcc/testsuite/g++.target/s390/pr100281-1.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'.*" } */
> +}
> diff --git a/gcc/testsuite/g++.target/s390/pr100281-2.C b/gcc/testsuite/g++.target/s390/pr100281-2.C
> new file mode 100644
> index 00000000000..58552becd7c
> --- /dev/null
> +++ b/gcc/testsuite/g++.target/s390/pr100281-2.C
> @@ -0,0 +1,9 @@
> +// PR C++/100281
> +// { dg-do compile }
> +
> +typedef int & __attribute__((mode (SI))) __ref32_t;
> +
> +void foo () {
> +  unsigned int b = 100;
> +  __ref32_t a = b; /* { dg-error "cannot bind non-const lvalue reference of type '__ref32_t'.*" } */
> +}
> diff --git a/gcc/tree.c b/gcc/tree.c
> index 01eda553a65..e92cae286d4 100644
> --- a/gcc/tree.c
> +++ b/gcc/tree.c
> @@ -6792,9 +6792,10 @@ operation_no_trapping_overflow (tree type, enum tree_code code)
>     constructed by language-dependent code, not here.)  */
>
>  /* Construct, lay out and return the type of pointers to TO_TYPE with
> -   mode MODE.  If CAN_ALIAS_ALL is TRUE, indicate this type can
> -   reference all of memory. If such a type has already been
> -   constructed, reuse it.  */
> +   mode MODE.  If MODE is VOIDmode, a pointer mode for the address
> +   space of TO_TYPE will be picked.  If CAN_ALIAS_ALL is TRUE,
> +   indicate this type can reference all of memory. If such a type has
> +   already been constructed, reuse it.  */
>
>  tree
>  build_pointer_type_for_mode (tree to_type, machine_mode mode,
> @@ -6806,6 +6807,12 @@ build_pointer_type_for_mode (tree to_type, machine_mode mode,
>    if (to_type == error_mark_node)
>      return error_mark_node;
>
> +  if (mode == VOIDmode)
> +    {
> +      addr_space_t as = TYPE_ADDR_SPACE (to_type);
> +      mode = targetm.addr_space.pointer_mode (as);
> +    }
> +
>    /* If the pointed-to type has the may_alias attribute set, force
>       a TYPE_REF_CAN_ALIAS_ALL pointer to be generated.  */
>    if (lookup_attribute ("may_alias", TYPE_ATTRIBUTES (to_type)))
> @@ -6857,10 +6864,7 @@ build_pointer_type_for_mode (tree to_type, machine_mode mode,
>  tree
>  build_pointer_type (tree to_type)
>  {
> -  addr_space_t as = to_type == error_mark_node? ADDR_SPACE_GENERIC
> -                                             : TYPE_ADDR_SPACE (to_type);
> -  machine_mode pointer_mode = targetm.addr_space.pointer_mode (as);
> -  return build_pointer_type_for_mode (to_type, pointer_mode, false);
> +  return build_pointer_type_for_mode (to_type, VOIDmode, false);
>  }
>
>  /* Same as build_pointer_type_for_mode, but for REFERENCE_TYPE.  */
> @@ -6875,6 +6879,12 @@ build_reference_type_for_mode (tree to_type, machine_mode mode,
>    if (to_type == error_mark_node)
>      return error_mark_node;
>
> +  if (mode == VOIDmode)
> +    {
> +      addr_space_t as = TYPE_ADDR_SPACE (to_type);
> +      mode = targetm.addr_space.pointer_mode (as);
> +    }
> +
>    /* If the pointed-to type has the may_alias attribute set, force
>       a TYPE_REF_CAN_ALIAS_ALL pointer to be generated.  */
>    if (lookup_attribute ("may_alias", TYPE_ATTRIBUTES (to_type)))
> @@ -6926,10 +6936,7 @@ build_reference_type_for_mode (tree to_type, machine_mode mode,
>  tree
>  build_reference_type (tree to_type)
>  {
> -  addr_space_t as = to_type == error_mark_node? ADDR_SPACE_GENERIC
> -                                             : TYPE_ADDR_SPACE (to_type);
> -  machine_mode pointer_mode = targetm.addr_space.pointer_mode (as);
> -  return build_reference_type_for_mode (to_type, pointer_mode, false);
> +  return build_reference_type_for_mode (to_type, VOIDmode, false);
>  }
>
>  #define MAX_INT_CACHED_PREC \
> --
> 2.30.2
>
>