Re: [PATCH 1/3] do full type check in COPY_ARRAY and MOVE_ARRAY

From

Junio C Hamano <gitster@pobox.com>

Date

Jan 1, 2023, 12:11 UTC

Message-ID

<xmqqzgb2fo8g.fsf@gitster.g>

In-Reply-To

<bf4e6798-c687-270d-1344-37bacb403e13@web.de>

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?

> We actually need to compare the types of the elements here, because
> otherwise we'd disallow copies between arrays (int arr[7]) and pointers
> (int *p), which would be unnecessarily strict.