Re: Proposal for merging scalar-storage-order branch into mainline

[pinskia]

> On Jun 9, 2015, at 7:53 PM, Richard Biener <richard.guent...@gmail.com> wrote:
> 
> On Tue, Jun 9, 2015 at 1:12 PM, Eric Botcazou <ebotca...@adacore.com> wrote:
>>> Yes, but I'd expect them to be optimized away (well, hopefully).
>> 
>> OK, but you cannot reasonably expose everything in GENERIC/GIMPLE, for 
>> example
>> the mask-and-shift operations to extract bitfields in reverse SSO, only the
>> RTL expander has the (quite complex) logic and I doubt you want to teach the
>> GIMPLE optimizers about this low-level mess.
> 
> Why would you want to support this on bitfields ... (/me runs away).

Because some folks don't want to audit their code to where to add byteswaps. I 
am serious people have legacy big-endian code they want to run little endian. 
There is a reason this is around in the first place. Developers are lazy. 

Thanks,
Andrew

> 
>>> Anwyay, and I thought use of the feature would be rare so that "every load
>>> and store" is still very few?
>> 
>> Experience has shown that, when users start to use it, they use it 
>> extensively
>> (too extensively if you ask me) so the implementation cannot be too dumb.
> 
> :/
> 
>> --
>> Eric Botcazou