Re: [PATCH] mergesort: avoid left shift overflow

From: Philip Oakley <philipoakley@iee.email>
Date: Nov 18, 2021, 23:27 UTC
Message-ID: <7fbd4cf4-5f66-a4cd-0c41-e5b12d14d761@iee.email>
In-Reply-To: <5eabbe1c-4c0f-559a-da21-423afec89e7e@web.de>

On 15/11/2021 23:19, René Scharfe wrote:

Show 25 quoted lines

> Use size_t to match n when building the bitmask for checking whether a
> rank is occupied, instead of the default signed int.
>
> Signed-off-by: René Scharfe <l.s.r@web.de>
> ---
> Ugh, sorry. :(
>
>  mergesort.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mergesort.c b/mergesort.c
> index 6216835566..bd9c6ef8ee 100644
> --- a/mergesort.c
> +++ b/mergesort.c
> @@ -63,7 +63,7 @@ void *llist_mergesort(void *list,
>  		void *next = get_next_fn(list);
>  		if (next)
>  			set_next_fn(list, NULL);
> -		for (i = 0; n & (1 << i); i++)
> +		for (i = 0; n & ((size_t)1 << i); i++)
>  			list = llist_merge(ranks[i], list, get_next_fn,
>  					   set_next_fn, compare_fn);
>  		n++;
> --
> 2.33.1

Looks good to me.

I already had this locally as part of an MSVC (Visual Studio) fix for the various C4334 warnings.

The other cases are in object-file.c, diffcore-delta.c (2 occurrences) , and repack.c.

My patches are in https://github.com/PhilipOakley/git/tree/oneU_t

Philip