RISC-V ELF multilibs

[Sebastian Huber]

On 29/05/18 20:02, Jim Wilson wrote:
>> Most variants include the C extension. Would it be possible to add 
>> -march=rv32g and -march=rv64g variants?
>
> The expectation is that most implementations will include the C 
> extension.  It reduces code size, improves performance, and I think I 
> read somewhere that it takes only 400 gates to implement.
>
> It isn't practical to try to support every possible combination of 
> architecture and ABI here, as there are too many possible 
> combinations. But if there is a major RISC-V target that is rv32g or 
> rv64g then we should consider it.  You can of course define your own 
> set of multilibs.

I am not a hardware developer, but I heard that the C extension is not 
easy to implement in out of order machines. For example:

https://www2.eecs.berkeley.edu/Pubs/TechRpts/2017/EECS-2017-157.html

-- 
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