Re: [Qemu-devel] [PATCH 5/6] Do constant folding for shift operations.

[Richard Henderson]

On 05/26/2011 01:25 PM, Blue Swirl wrote:
>> I don't see the point.  The C99 implementation defined escape hatch
>> exists for weird cpus.  Which we won't be supporting as a QEMU host.
> 
> Maybe not, but a compiler with this property could arrive. For
> example, GCC developers could decide that since this weirdness is
> allowed by the standard, it may be implemented as well.

If you like, you can write a configure test for it.  But, honestly,
essentially every place in qemu that uses shifts on signed types
would have to be audited.  Really.

The C99 hook exists to efficiently support targets that don't have
arithmetic shift operations.  Honestly.


r~