On 12/31/20 4:34 PM, Xi Ruoyao via Gcc-patches wrote:
> On 2021-01-01 07:29 +0800, Xi Ruoyao wrote:
>> An invalid use of MSA_SUPPORTED_MODE_P is causing ICE on mips64el with -mmsa.
>> The detailed analysis is posted on bugzilla:
>>
>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98491
>>
>> The attached patch fixes this issue by handling the special case of
>> MSA_SUPPORTED_MODE_P explicitly.
>>
>> Please keep me in CC since I'm not a subscriber.
>>
>> And, I don't have GIT write access.
> Sorry, I forgot to include the ChangeLog:
>
>     gcc/ChangeLog:
>     
>     2020-12-31  Xi Ruoyao <xry111@mengyan1223.wang>
>     
>             PR target/98491
>             * config/mips/mips.c (mips_symbol_insns): Do not use
>               MSA_SUPPORTED_MODE_P if mode is MAX_MACHINE_MODE.
So I absolutely agree the current code is wrong as it does an out of
bounds array access.


Would it be better to instead to change MSA_SUPPORTED_MODE_P to evaluate
to zero if MODE is MAX_MACHINE_MODE?  That would protect all the uses of
MSA_SUPPORTED_MODE_P.    Something like this perhaps?



Jeff