Hi Kyrylo,

On 19/08/15 13:46, Kyrylo Tkachov wrote:
> Hi Renlin,
>
> Please send patches to gcc-patches for review.
> Redirecting there now...
Thank you! I should really double check after Thunderbird auto complete 
the address for me.

>
> On 19/08/15 12:49, Renlin Li wrote:
>> Hi all,
>>
>> This simple patch will tighten the conditions when matching movw and
>> arm_movt rtx pattern.
>> Those two patterns will generate the following assembly:
>>
>> movw w1, #:lower16: dummy + addend
>> movt w1, #:upper16: dummy + addend
>>
>> The addend here is optional. However, it should be an 16-bit signed
>> value with in the range -32768 <= A <= 32768.
>>
>> By impose this restriction explicitly, it will prevent LRA/reload code
>> from generation invalid high/lo_sum code for arm target.
>> In process_address_1(), if the address is not legitimate, it will try to
>> generate high/lo_sum pair to put the address into register. It will
>> check if the target support those newly generated reload instructions.
>> By define those two patterns, arm will reject them if conditions is not
>> meet.
>>
>> Otherwise, it might generate movw/movt instructions with addend larger
>> than 32768, this will cause a GAS error. GAS will produce '''offset out
>> of range'' error message when the addend for MOVW/MOVT REL relocation is
>> too large.
>>
>>
>> arm-none-eabi regression tests Okay, Okay to commit to the trunk and
>> backport to 5.0?
>>
>> Regards,
>> Renlin
>>
>> gcc/ChangeLog:
>>
>> 2015-08-19  Renlin Li  <renlin.li@arm.com>
>>
>>        * config/arm/arm-protos.h (arm_valid_symbolic_address_p): Declare.
>>        * config/arm/arm.c (arm_valid_symbolic_address_p): Define.
>>        * config/arm/arm.md (arm_movt): Use arm_valid_symbolic_address_p.
>>        * config/arm/constraints.md ("j"): Add check for high code.
>
> Is it guaranteed that at this point XEXP (tmp, 0) and XEXP (tmp, 1) are valid?
> I think before you extract xop0 and xop1 you want to check that tmp is indeed a PLUS
> and return false if it's not. Only then you should extract XEXP (tmp, 0) and XEXP (tmp, 1).
>
>   +  if (GET_CODE (tmp) == PLUS && GET_CODE (xop0) == SYMBOL_REF
> +      && CONST_INT_P (xop1))
> +    {
> +      HOST_WIDE_INT offset = INTVAL (xop1);
> +      if (offset < -0x8000 || offset > 0x7fff)
> +	return false;
> +      else
> +	return true;
>
> I think you can just do "return IN_RANGE (offset, -0x8000, 0x7ffff);"
Updated accordingly, please check the latest attachment.

Thank you,
Renlin