(C++) mangling vector types

[Jason Merrill]

On 11/12/2009 11:14 AM, Ulrich Drepper wrote:
> On 11/12/2009 07:24 AM, Jason Merrill wrote:
>> c) Use -fabi-version=2.1.
>
> I'd favor this if you can emit aliases with the old names wherever this
> is possible and currently done.

I suppose if we unconditionally use the new mangling and emit a weak 
alias with the old mangling, old external references will resolve to 
somthing, so code that only uses one vector size will continue to work; 
if newer code uses multiple vector sizes then references in old code may 
resolve to the wrong one, but that seems unavoidable.

I suppose that is the best solution, as a partial rebuild of an old code 
base should continue to work in all cases, and all new code will also 
work fine.

Jason