[PATCH v5] dse: Remove partial load after full store for high part access[PR71309]

[luoxhu]

On 2020/8/3 22:01, Richard Sandiford wrote:

>>         /* Try a wider mode if truncating the store mode to NEW_MODE
>>   	 requires a real instruction.  */
>>         if (maybe_lt (GET_MODE_SIZE (new_mode), GET_MODE_SIZE (store_mode))
>> @@ -1779,6 +1780,25 @@ find_shift_sequence (poly_int64 access_size,
>>   	  && !targetm.modes_tieable_p (new_mode, store_mode))
>>   	continue;
>>   
>> +      if (multiple_p (GET_MODE_BITSIZE (new_mode), shift)
> 
> Like I mentioned before, this should be the other way around:
> 
>      multiple_p (shift, GET_MODE_BITSIZE (new_mode))
> 
> i.e. for the subreg to be valid, the shift amount must be a multiple
> of the outer mode size in bits.
> 
> OK with that change, thanks, and sorry for the multiple review cycles.

Appreciate your time and patience to make it better :).
Updated the change and lp64 requirements from Segher and committed by
r11-2526-g265d817b1eb4644c7a9613ad6920315d98e2e0a4, thank you all.

Xionghu

> 
> Richard
>