[LLVMdev] Issues with inline assembly

[Stephen Checkoway]

On Nov 20, 2013, at 4:11 PM, Ghitulete Razvan <razvan.ghitulete at gmail.com> wrote:

> On Wed, Nov 20, 2013 at 8:55 PM, Stephen Checkoway <s at pahtak.org> wrote:
>> 
>> This has come up before <https://groups.google.com/forum/#!topic/llvm-dev/vomnIQjefzA>. I don't recall if there was a resolution.
>> 
> 
> Thanks for the link, completely missed when googled the issue. I think
> no consensus was reached (I cannot find any commit in the repository
> addressing such issues). I will try and search for the culprit of the
> inline assembly and replace it with btsl.
> 
> As for the issue at hand, although after carefully reading both the
> thread and re-reading the sections from the instructions set reference
> it is a rather unpleasant behavior, the error thrown by the toolchain.
> Since Intel is nowadays by far the biggest vendor for x86/x86_64
> hardware and they do not mention a single thing about the existence of
> suffixes for this instruction, it could be accommodated (maybe with a
> warning though) and take the second option from the 3 you provided.

One thing to note is that Intel syntax doesn't use suffixes for most (all?) instructions whereas AT&T syntax does. (Although, as I recall, no one actually found an authoritative description of AT&T syntax.) Thus it makes sense that Intel would say nothing about it.


> 
> P.S. : after searching a bit more, it seems that llvm is in fact the
> only toolchain that rejects/complains about the bts ambiguity, or at
> least people using llvm get annoyed more easily and start spamming
> mailing lists :).

Certainly possible!


-- 
Stephen Checkoway