From: René Scharfe <l.s.r@web.de>
Date: Sun, 01 Jan 2023 12:32:11 GMT
Subject: Re: [PATCH 1/3] do full type check in COPY_ARRAY and MOVE_ARRAY
Message-ID: <269d85de-1448-0198-8251-9af898fedc67@web.de>
In-Reply-To: <xmqqzgb2fo8g.fsf@gitster.g>

Am 01.01.23 um 13:11 schrieb Junio C Hamano:
> René Scharfe <l.s.r@web.de> writes:
>
>> On second thought, what do we gain by using __builtin_types_compatible_p
>> here?  Does it catch cases that the assignment check plus the element
>> size check wouldn't?
>
> I was reacting to this part of an earlier message in the thread:
>
> Presumably we cannot catch
>
> 	int *ip;
> 	unsigned *up;
>
> 	(0 ? (*(ip) = *(up), 0) : 0);
> 	(0 ? (*(up) = *(ip), 0) : 0);
>
> with the approach?
>
> i.e. *ip and *up are of the same size.  Would the assignment check
> trigger?

Ah, right, __builtin_types_compatible_p returns 0 in this case and an
assignment is silently allowed.

René