[PATCH v3 1/6] mips: Restrict the use of addiupc for microMIPSr6

Adhemerval Zanella Netto adhemerval.zanella@linaro.org
Wed Sep 17 21:00:42 GMT 2025



On 17/09/25 17:51, H.J. Lu wrote:
> On Wed, Sep 17, 2025 at 1:16 PM Adhemerval Zanella Netto
> <adhemerval.zanella@linaro.org> wrote:
>>
>>
>>
>> On 03/09/25 10:53, Jovan Dmitrovic wrote:
>>> For microMIPSr6, even though the ADDIUPC instruction is supported,
>>> it requires for the address to be 4-byte aligned, which might not
>>> be the case in all scenarios.
>>
>> The looks ok, although it is not clear to me if this is actually tested
>> since it seems that mipsisa64r6el does not support -mmicromips. Should
>> we add a mipsisa64r5el-linux-gnu target to build-many-glibcs.py?
>>
>> As a side note, it seems that mips16 is broken with --enable-profile
>> or a long time and since 2.34 (035c012e32c11e84d64905efaf55e74f704d3668)
>> without it:
>>
>> $ mips64-glibc-linux-gnu-gcc -mabi=32 -mips16 ../sysdeps/mips/start.S
>> [...]
>> libc/build/mips-linux-gnu-mips16/csu/start.o
>> ../sysdeps/mips/start.S: Assembler messages:
>> ../sysdeps/mips/start.S:147: Error: invalid operands `sw $0,16($sp)'
>> [...]
>>
>> Should we remove mips16 support?
>>
> 
> Does mips16 support 32-bit displacement for TLS? If not, it may have the same
> issue as ColdFire:
> 
> https://sourceware.org/bugzilla/show_bug.cgi?id=33429
> 

I am not sure, maybe someone from htecgroup could answer. But it has been
broken since 2021 without complains or bug reports.


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