On 2021-12-02 12:21, Vladimir Makarov via Gcc-patches wrote:
>
> On 2021-12-02 12:06, Vladimir Makarov wrote:
>>
>>
>> So simple problem and so many details :)
>>> This will require that long long is at least twice as large as int
>>> everywhere, I thought you wanted to do that only when
>>> __builtin_smul_overflow isn't available.
>>
>> That is not critical as GCC and probably all others C++ compiler 
>> support only targets with this assertion.  I guess it is better to 
>> find this problem earlier on targets (if any) where it is not true 
>> *independently* on used compiler.
>>
>> So it is difficult for me to know what is better.  Probably for 
>> GCC/Clang oriented world, your variant is better as it permits to 
>> compile the code by GCC even on targets where the assertion is false.
>>
>>
> After some more considerations, I think you are right and the backup 
> code should be conditional.  Because otherwise, there is no sense to 
> use code with __builtin_smul_overflow.  I'll do the changes.
>
>
Here is one more patch I've committed.  Jakub, thank your for the 
discussion and your patience.