From: Jakub Jelinek <jakub@redhat.com>
To: Jason Merrill <jason@redhat.com>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] c++: Fix ICE with __builtin_bit_cast [PR98469]
Date: Mon, 4 Jan 2021 21:48:20 +0100 [thread overview]
Message-ID: <20210104204820.GB725145@tucnak> (raw)
In-Reply-To: <b332c655-d468-197b-0ce5-26ad745782f5@redhat.com>
On Mon, Jan 04, 2021 at 03:44:46PM -0500, Jason Merrill wrote:
> This change is OK, but part of the problem is that we're trying to do
> overload resolution for an S copy/move constructor, which we shouldn't be
> because bit_cast is a prvalue, so in C++17 and up we should use it to
> directly initialize the target without any implied constructor call.
>
> It seems we're mishandling this because the code in
> build_special_member_call specifically looks for TARGET_EXPR or CONSTRUCTOR,
> and BIT_CAST_EXPR is neither of those.
>
> Wrapping a BIT_CAST_EXPR of aggregate type in a TARGET_EXPR would address
> this, and any other places that expect a class prvalue to come in the form
> of a TARGET_EXPR.
I can try that tomorrow. Won't that cause copying through extra temporary
in some cases though, or is that guaranteed to be optimized?
Jakub
next prev parent reply other threads:[~2021-01-04 20:48 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-30 9:13 Jakub Jelinek
2021-01-04 20:44 ` Jason Merrill
2021-01-04 20:48 ` Jakub Jelinek [this message]
2021-01-04 21:01 ` Jason Merrill
2021-01-05 15:26 ` [PATCH] c++, v2: " Jakub Jelinek
2021-01-05 16:00 ` Jason Merrill
2021-01-07 21:11 ` Jason Merrill
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