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From: "ibuclaw at gdcproject dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug d/110712] d: ICE: verify_gimple_failed (conversion of register to a different size in 'view_convert_expr')
Date: Wed, 19 Jul 2023 15:16:42 +0000 [thread overview]
Message-ID: <bug-110712-4-kItLSDQPm7@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-110712-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110712
--- Comment #2 from Iain Buclaw <ibuclaw at gdcproject dot org> ---
(In reply to Richard Biener from comment #1)
> this_2(D)->ap = VIEW_CONVERT_EXPR<struct [1]>(ap_3(D));
>
> it looks odd since ap_3(D) is a is_gimple_reg but a struct[1] definitely
> would not. Maybe you are missing a dereference here? In C
> struct[1] would decay to a pointer so
>
> this.ap = ap;
>
> wouldn't work (besides that va_list copying requires va_copy).
Static arrays in D are passed around by value, rather than decaying to a
pointer. However va_list is an inconsistent type on this front.
In some D compilers, it's always a pointer type to get around the
incompatibility with C/C++ - though this requires locals and fields to be
specially initialized before being passed to va_start() or va_copy().
i.e, underneath the hood it does:
---
void va_start(T)(out va_list ap, ref T parmn,
va_list storage = alloca(__va_list_tag.sizeof))
{
ap = storage;
// initialize *ap
}
void va_copy(out va_list ap, va_list src,
va_list storage = alloca(__va_list_tag.sizeof))
{
ap = storage;
// copy *src.
}
---
GDC doesn't do this, rather - in a way that mimics C/C++ - va_list static
arrays are decayed to a pointer type when used as a parameter, but semantically
it's still treated as a static array.
I think some extra errors during the D front-end codegen pass are likely the
most appropriate thing to do here, as you say, such things are rejected by
C/C++, so GDC ought to reject them too.
next prev parent reply other threads:[~2023-07-19 15:16 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-18 10:37 [Bug d/110712] New: " ibuclaw at gdcproject dot org
2023-07-18 11:55 ` [Bug d/110712] " rguenth at gcc dot gnu.org
2023-07-19 15:16 ` ibuclaw at gdcproject dot org [this message]
2023-07-19 15:24 ` ibuclaw at gdcproject dot org
2023-10-29 19:21 ` cvs-commit at gcc dot gnu.org
2023-10-29 19:23 ` cvs-commit at gcc dot gnu.org
2023-10-29 19:23 ` cvs-commit at gcc dot gnu.org
2023-10-29 19:25 ` ibuclaw at gcc dot gnu.org
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