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From: "joseph at codesourcery dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/97986] ICE in force_constant_size when applying va_arg to VLA
 type
Date: Wed, 25 Nov 2020 21:33:19 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D97986

--- Comment #1 from joseph at codesourcery dot com <joseph at codesourcery =
dot com> ---
I guess this should be handled like va_arg for float: give a warning about=
=20
the type passed, then generate an abort (making sure that side-effects in=20
both arguments take effect before the abort, in case a side-effect=20
involves calling longjmp or exit).

(Technically a fixed-size array type argument to va_arg could be used in=20
C90 mode to retrieve a non-lvalue array passed by value as a function=20
argument, but the result would just be another non-lvalue array with no=20
way to access the array elements, so just as useless as all other cases of=
=20
non-lvalue arrays in C90.  So although specifying any array type as the=20
second argument to va_arg is very dubious, maybe the case of a non-VLA in=20
C90 mode should not generate an abort.)=