[0/3] Fix PR78120, in ifcvt/rtlanal/i386.

[Jeff Law]

On 11/24/2016 08:16 AM, Richard Biener wrote:
>>
>> IMHO switching insn_rtx_cost to be based on not just set_src_cost is
>> a good idea, but will require re-tuning of all targets, so it is not
>> stage 3 material.
>
> Agreed.
>
>> That we compare different kinds of costs (which really has no meaning at
>> all, it's a heuristic at best) in various places is a known problem, not
>> a regression.
>
> But technically stage 3 is for general bugfixing, not only regression fixing.
>
> I'd say be prepared to revert but wait to see who screams first.
Right.  And I would claim that we're early enough in stage3 that 
attempting to address this BZ is a good thing.  The BZ also happens to 
be a 6/7 regression.

So I'd say let's go with the patch, but be aware that there may be a 
need to twiddle other ports.  If we find a bunch of ports are 
problematical than we might need to think about reversion.

jeff