Re: [PATCH 1/4] mergesort.c: LLP64 compatibility, upcast unity for left shift

From: Philip Oakley <philipoakley@iee.email>
Date: Nov 29, 2021, 23:49 UTC
Message-ID: <384f10ca-81c5-dd89-b66c-6e49d7f23f70@iee.email>
In-Reply-To: <9c3d6d3c-1f3b-f51c-6856-b5ced44a8f4b@web.de>

On 27/11/2021 07:32, René Scharfe wrote:

Show 17 quoted lines

> Am 26.11.21 um 12:36 schrieb Philip Oakley:
>> Visual Studio reports C4334 "was 64-bit shift intended" size mismatch
>> warning because of size miss-match.
>>
>> Promote unity to the matching type to fit with the `&` operator.
>>
>> Signed-off-by: Philip Oakley <philipoakley@iee.email>
>>
>> ---
>> This is the same fix that René Scharfe provided in 42c456ff81
>> (mergesort: avoid left shift overflow, 2021-11-16)
>>
>> Use size_t to match n when building the bitmask for checking whether a
>> rank is occupied, instead of the default signed int.
> Fine with me -- it's just nicer to take the whole set.
>
> René

Thanks, I'm happy either way if others feels it belongs better with your mergesort series.

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>
>> ---
>>  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++;
>>

Philip