[PATCH] Find more cases for AUTO_INC_DEC

Dale Johannesen dalej@apple.com
Mon Jul 18 21:50:00 GMT 2005


On Jul 18, 2005, at 2:48 PM, Dale Johannesen wrote:

>
> On Jul 16, 2005, at 1:40 PM, Adam Nemet wrote:
>
>> Hi,
>>
>> Mainline has stopped optimizing the following function into stuw
>> (pre-increment) on PowerPC:
>
> It turns out this is not necessarily the right thing to do on G5.  The 
> hardware
> "cracks" this insn into an add and a load internally anyway, and you

s/load/store/  , but you knew that.  Same considerations apply to lduw 
etc.

> may get better scheduling in some cases by allowing them to be 
> separated.
> The recommendation of Apple's performance group was not to generate it
> at speed-oriented optimization levels.  It it still a win on size, of 
> course.



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