[24/27] Put gcse's can_copy hash into target structures

[Andrew Pinski]

On Jul 11, 2010, at 1:15 PM, IainS <developer@sandoe-acoustics.co.uk>  
wrote:

>
> On 11 Jul 2010, at 21:03, Andrew Pinski wrote:
>>
>> On Jul 11, 2010, at 12:54 PM, Mike Stump <mikestump@comcast.net>  
>> wrote:
>>
>>> On Jul 10, 2010, at 6:59 AM, Richard Sandiford wrote:
>>>>> For the most part I think *most* of the "char" variables that
>>>>> you're moving should really be "bool".  However, I think that
>>>>> should be done in separate changes.
>>>>
>>>> Yeah, agreed that bool would be nicer.  I vaguely recall a  
>>>> discussion
>>>> about whether that was a good idea though, given that hosts like  
>>>> Darwin
>>>> define bool to be wider than char.  More fool them, I suppose.
>>>
>>> :-)  Hey, for -fwhole-program, is there a narrowing pass that can  
>>> change 4 byte variables into 1 byte variables?  I'd not object to  
>>> using the arguably better bool for these things.  bool is only 4  
>>> bytes on ppc, not on any of the x86 targets.
>>
>>
>> Actually bool is only 4 bytes on ppc Darwin. No other host or  
>> target. From what I remember this was done not to break the abi. I  
>> would say let's not worry about ppc Darwin as a host any more as  
>> there are no new versions of the os being released.
>
> Fair enough that there should be little if any priority for future  
> development.
>
> Conversely FSF gcc is the *only* compiler with any modern  
> development for the remaining useful ppc systems (one of which I'm  
> typing this on).
> Despite the ideals of Hacking Heaven .. most of us cannot afford to  
> toss away good quality working hardware that is < 5 years old :-)
> Please don't break it unless it's actually necessary.
>

The use of bool is not going to break anything; just might slow down  
the compiler slightly. The data cache might be fuller.  Don't be  
scared away because the compiler slows down for a little bit while  
things are in flux to speed up in the long term.



> (and yes, I do have other systems, including an 8-core intel system,  
> but this quad g5 _is_ still useful).
> Iain
>