[swift-dev] Value-result ABI for small trivial inouts

[Joe Groff]

> On Dec 17, 2015, at 3:43 PM, Greg Parker <gparker at apple.com> wrote:
> 
> 
>> On Dec 17, 2015, at 3:34 PM, Joe Groff via swift-dev <swift-dev at swift.org> wrote:
>> 
>> On ARMv7 and ARM64, the argument and return register sets are the same
> 
> Nit: True on arm64. Not true on armv7; the GPR parameters are r0-r3 but GPR return is r0-r1.

True, I meant that one sequence is a prefix of the other. If you pass the first argument in and return it out via {r0, r1} the operations could be done in-place.

-Joe