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

[Nicolas Cellier]

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

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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