[PATCH] powerpc: Fix POWER7/PPC64 performance regression on LE

[Adhemerval Zanella]

On 13-01-2015 18:11, Richard Henderson wrote:
> On 01/13/2015 11:43 AM, Adhemerval Zanella wrote:
>> +	std	rWORD8, rWORD8SAVE(r1)
>> +	cfi_offset(rWORD8, rWORD8SAVE)
>> +	std	rWORD7, rWORD7SAVE(r1)
>> +	cfi_offset(rWORD7, rWORD7SAVE)
>> +	std	rOFF8, rOFF8SAVE(r1)
>> +	cfi_offset(rWORD7, rOFF8SAVE)
>> +	std	rOFF16, rOFF16SAVE(r1)
>> +	cfi_offset(rWORD7, rOFF16SAVE)
>> +	std	rOFF24, rOFF24SAVE(r1)
>> +	cfi_offset(rWORD7, rOFF24SAVE)
>> +	std	rOFF32, rOFF32SAVE(r1)
>> +	cfi_offset(rWORD7, rOFF32SAVE)
> Given a sequence of stores like this, it's better to
> put all of the cfi_offset annotations after the last store.
>
> By interspersing them like this, you're just adding unnecessary
> DW_CFA_advance opcodes to the unwind info.
>
>
> r~
>
I was not aware of this, but I think the performance implications for such
organization is just to unwind and debuggers, right?