Re: [PING][PATCH] RISC-V: Avoid redundant sign-extension for SImode SGE, SGEU, SLE, SLEU

[Jeff Law <jeffreyalaw@gmail.com>]

On 11/25/22 07:07, Maciej W. Rozycki wrote:
> Hi Kito,
>
> On Fri, 12 Aug 2022, Maciej W. Rozycki wrote:
>
>>> LGTM, but with a nit, I don't get set.w but get an andi like below, so
>>> maybe we should also scan-assembler-not andi? feel free to commit that
>>> directly with that fix
>>>
>>> ```asm
>>> sleu:
>>>         sgtu    a0,a0,a1        # 9     [c=4 l=4]  *sgtu_disi
>>>         xori    a0,a0,1 # 10    [c=4 l=4]  *xorsi3_internal/1
>>>         andi    a0,a0,1 # 16    [c=4 l=4]  anddi3/1
>>>         ret             # 25    [c=0 l=4]  simple_return
>>> ```
>>   Interesting.  I can do that, but can you please share the compilation
>> options, given or defaulted (from `--with...' configuration options), this
>> happens with?
>   I have noticed it went nowhere.  Can you please check what compilation
> options lead to this discrepancy so that we can have the fix included in
> GCC 13?  I'd like to understand what's going on here.

FWIW, I don't see the redundant sign extension with this testcase at -O2 
on the trunk.  Is it possible the patch has been made redundant over the 
last few months?


Jeff