[Vm-dev] about generating long long min literal...

[Nicolas Cellier]

2015-03-16 0:52 GMT+01:00 Nicolas Cellier <
nicolas.cellier.aka.nice at gmail.com>:

>
>
> 2015-03-15 3:36 GMT+01:00 Andres Valloud <
> avalloud at smalltalk.comcastbiz.net>:
>
>>
>> So how about keeping a copy of C99 handy?  Whenever you suspect a
>> compiler bug, see if you can use it to prove the compiler wrong. Obviously
>> compilers are not flawless, but it really helps to rule out cases of
>> garbage-in, garbage-out.
>>
>>
> Hi Andres
>
> For -1LL<<63, it's more readable for sure, but not more portable, see
>
> http://stackoverflow.com/questions/3784996/why-does-left-shift-operation-invoke-undefined-behaviour-when-the-left-side-oper
>
>
Oops, I missread this one too...
-1LL<<63 seems correct.


> For reading the C standard, I often take a shorter path: the question must
> have been raised on SO ;)
> This time I consulted gcc bug reports, and several were including this
> constant, thus my incorrect analysis at first.
> But for sure, the chances of discovering a bug is really tiny compared to
> the chances of miss-interpreting the standard!
>
> Nicolas
>
> On 3/13/15 16:47 , Nicolas Cellier wrote:
>>
>>> Ah, ah, it's not a gcc bug, it's just one another C pitfall...
>>>
>>
>
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