[PATCH ppc64,aarch64,alpha 00/15] Improve backend constant generation

[Richard Earnshaw]

On 12/08/15 09:43, Richard Earnshaw wrote:
> On 12/08/15 09:32, Richard Earnshaw wrote:
>> On 12/08/15 02:11, Richard Henderson wrote:
>>>     I'm somewhat surprised that the operands to the logicals aren't
>>>     visible at rtl generation time, given all the work done in gimple.
>>>     And failing that, combine has enough REG_EQUAL notes that it ought
>>>     to be able to put things back together and see the simpler pattern.
>>>
>>
>> We've tried it in the past.  Exposing the individual steps prevents the
>> higher-level rtl-based optimizations since they can no-longer deal with
>> the complete sub-expression.
> 
> Eg. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63724
> 
> R.
> 
And https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65768

R.