asm volatile statement reordering
Toebs Douglass
toby@winterflaw.net
Tue Oct 17 09:15:00 GMT 2017
On 17/10/17 08:58, Andrew Haley wrote:
> On 17/10/17 08:32, Jeffrey Walton wrote:
>> GCC guesses wrong on occasion. It will remove code that has value that
>> but does not produce an output because the language does not allow us
>> to express it.
>>
>> The C language lacks what we need to express what we need to do. Its a
>> failure of the C (and C++) committees. Its not a GCC failure.
>
> I disagree. If you want a bunch of asms to execute in a particular
> order, add a memory clobber or some dependencies. It's not difficult
> once you have the understanding. In this particular case, fixing it
> is trivial, and there are many ways to do it.
This is true, but - although I could be wrong - I think these solutions
are not part of the standards. They are GCC specific. Jeffrey was
talking about the C/C++ standards.
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