Hi Jason,
This commit caused boot-strap failure on aarch64. Is it a bug? Can this be
fixed ASAP?
../../gcc/gcc/expmed.c:5602:19: error: ���int_mode��� may be used uninitialized
in this function [-Werror=maybe-uninitialized]
5602 | scalar_int_mode int_mode;
| ^~~~~~~~
Thanks,
-Jiangning
> -----Original Message-----
> From: gcc-patches-ow...@gcc.gnu.org <gcc-patches-ow...@gcc.gnu.org>
> On Behalf Of Jason Merrill
> Sent: Monday, September 16, 2019 12:33 PM
> To: gcc-patches@gcc.gnu.org
> Subject: [C++ PATCH 2/4] Fix conversions for built-in operator overloading
> candidates.
>
> While working on C++20 operator<=>, I noticed that build_new_op_1 was
> doing too much conversion when a built-in candidate was selected; the
> standard says it should only perform user-defined conversions, and then
> leave the normal operator semantics to handle any standard conversions.
> This is important for operator<=> because a comparison of two different
> unscoped enums is ill-formed; if we promote the enums to int here,
> cp_build_binary_op never gets to see the original operand types, so we can't
> give the error.
>
> Tested x86_64-pc-linux-gnu, applying to trunk.
>
> * call.c (build_new_op_1): Don't apply any standard conversions to
> the operands of a built-in operator. Don't suppress conversions in
> cp_build_unary_op.
> * typeck.c (cp_build_unary_op): Do integral promotions for enums.
> ---
> gcc/cp/call.c | 51 ++++++++++++++++++++++++------------------------
> gcc/cp/typeck.c | 4 ++--
> gcc/cp/ChangeLog | 7 +++++++
> 3 files changed, 34 insertions(+), 28 deletions(-)
>
> diff --git a/gcc/cp/call.c b/gcc/cp/call.c index c3045d948c5..457fa6605c2
> 100644
> --- a/gcc/cp/call.c
> +++ b/gcc/cp/call.c
> @@ -6139,41 +6139,40 @@ build_new_op_1 (const op_location_t &loc,
> enum tree_code code, int flags,
> break;
> }
>
> - /* We need to strip any leading REF_BIND so that bitfields
> - don't cause errors. This should not remove any important
> - conversions, because builtins don't apply to class
> - objects directly. */
> + /* "If a built-in candidate is selected by overload resolution, the
> + operands of class type are converted to the types of the
> + corresponding parameters of the selected operation function,
> + except that the second standard conversion sequence of a
> + user-defined conversion sequence (12.3.3.1.2) is not applied."
> +*/
> conv = cand->convs[0];
> - if (conv->kind == ck_ref_bind)
> - conv = next_conversion (conv);
> - arg1 = convert_like (conv, arg1, complain);
> + if (conv->user_conv_p)
> + {
> + while (conv->kind != ck_user)
> + conv = next_conversion (conv);
> + arg1 = convert_like (conv, arg1, complain);
> + }
>
> if (arg2)
> {
> conv = cand->convs[1];
> - if (conv->kind == ck_ref_bind)
> - conv = next_conversion (conv);
> - else
> - arg2 = decay_conversion (arg2, complain);
> -
> - /* We need to call warn_logical_operator before
> - converting arg2 to a boolean_type, but after
> - decaying an enumerator to its value. */
> - if (complain & tf_warning)
> - warn_logical_operator (loc, code, boolean_type_node,
> - code_orig_arg1, arg1,
> - code_orig_arg2, arg2);
> -
> - arg2 = convert_like (conv, arg2, complain);
> + if (conv->user_conv_p)
> + {
> + while (conv->kind != ck_user)
> + conv = next_conversion (conv);
> + arg2 = convert_like (conv, arg2, complain);
> + }
> }
> +
> if (arg3)
> {
> conv = cand->convs[2];
> - if (conv->kind == ck_ref_bind)
> - conv = next_conversion (conv);
> - convert_like (conv, arg3, complain);
> + if (conv->user_conv_p)
> + {
> + while (conv->kind != ck_user)
> + conv = next_conversion (conv);
> + arg3 = convert_like (conv, arg3, complain);
> + }
> }
> -
> }
> }
>
> @@ -6241,7 +6240,7 @@ build_new_op_1 (const op_location_t &loc, enum
> tree_code code, int flags,
> case REALPART_EXPR:
> case IMAGPART_EXPR:
> case ABS_EXPR:
> - return cp_build_unary_op (code, arg1, candidates != 0, complain);
> + return cp_build_unary_op (code, arg1, false, complain);
>
> case ARRAY_REF:
> return cp_build_array_ref (input_location, arg1, arg2, complain); diff
> --git
> a/gcc/cp/typeck.c b/gcc/cp/typeck.c index 70094d1b426..620f2c9afdf 100644
> --- a/gcc/cp/typeck.c
> +++ b/gcc/cp/typeck.c
> @@ -6242,7 +6242,7 @@ cp_build_unary_op (enum tree_code code, tree
> xarg, bool noconvert,
> : _("wrong type argument to unary plus"));
> else
> {
> - if (!noconvert && CP_INTEGRAL_TYPE_P (TREE_TYPE (arg)))
> + if (!noconvert && INTEGRAL_OR_ENUMERATION_TYPE_P
> (TREE_TYPE
> +(arg)))
> arg = cp_perform_integral_promotions (arg, complain);
>
> /* Make sure the result is not an lvalue: a unary plus or minus @@
> -6267,7 +6267,7 @@ cp_build_unary_op (enum tree_code code, tree xarg,
> bool noconvert,
> |
> WANT_VECTOR_OR_COMPLEX,
> arg, true)))
> errstring = _("wrong type argument to bit-complement");
> - else if (!noconvert && CP_INTEGRAL_TYPE_P (TREE_TYPE (arg)))
> + else if (!noconvert && INTEGRAL_OR_ENUMERATION_TYPE_P
> (TREE_TYPE
> + (arg)))
> {
> /* Warn if the expression has boolean value. */
> if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE diff --git
> a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index e92d49f1b76..a03a428109b
> 100644
> --- a/gcc/cp/ChangeLog
> +++ b/gcc/cp/ChangeLog
> @@ -1,3 +1,10 @@
> +2019-09-15 Jason Merrill <ja...@redhat.com>
> +
> + * call.c (build_new_op_1): Don't apply any standard conversions to
> + the operands of a built-in operator. Don't suppress conversions in
> + cp_build_unary_op.
> + * typeck.c (cp_build_unary_op): Do integral promotions for enums.
> +
> 2019-09-15 Marek Polacek <pola...@redhat.com>
>
> PR c++/91740 - ICE with constexpr call and ?: in ARRAY_REF.
> --
> 2.21.0
