Re: [PATCH-for-10.2 2/2] tcg/tci: Disable Int128 support

[Richard Henderson <richard.henderson@linaro.org>]

On 12/2/25 14:30, Richard Henderson wrote:
> On 12/2/25 10:46, Philippe Mathieu-Daudé wrote:
>> Disable Int128 on TCI, otherwise build fails:
>>
>>    In file included from ../../tcg/optimize.c:29:
>>    In file included from include/tcg/tcg-op-common.h:12:
>>    In file included from include/exec/helper-proto-common.h:10:
>>    In file included from include/qemu/atomic128.h:62:
>>    In file included from host/include/aarch64/host/atomic128-cas.h.inc:16:
>>    host/include/generic/host/atomic128-cas.h.inc:37:12: error: initializing 
>> 'Int128' (aka 'struct Int128') with an expression of incompatible type '__int128_t' (aka 
>> '__int128')
>>       37 |     Int128 old = *ptr_align;
>>          |            ^     ~~~~~~~~~~
>>    host/include/generic/host/atomic128-cas.h.inc:39:52: warning: incompatible pointer 
>> types passing 'Int128 *' (aka 'struct Int128 *') to parameter of type '__int128_t 
>> *' (aka '__int128 *') [-Wincompatible-pointer-types]
>>       39 |     while (!__atomic_compare_exchange_n(ptr_align, &old, new, true,
>>          |                                                    ^~~~
>>    host/include/generic/host/atomic128-cas.h.inc:39:58: error: passing 'Int128' (aka 
>> 'struct Int128') to parameter of incompatible type '__int128_t' (aka '__int128')
>>       39 |     while (!__atomic_compare_exchange_n(ptr_align, &old, new, true,
>>          |                                                          ^~~
>>    host/include/generic/host/atomic128-cas.h.inc:50:12: error: initializing 
>> 'Int128' (aka 'struct Int128') with an expression of incompatible type '__int128_t' (aka 
>> '__int128')
>>       50 |     Int128 old = *ptr_align;
>>          |            ^     ~~~~~~~~~~
>>    host/include/generic/host/atomic128-cas.h.inc:52:62: error: invalid operands to 
>> binary expression ('Int128' (aka 'struct Int128') and 'Int128')
>>       52 |     while (!__atomic_compare_exchange_n(ptr_align, &old, old & val, true,
>>          |                                                          ~~~ ^ ~~~
>>    host/include/generic/host/atomic128-cas.h.inc:63:12: error: initializing 
>> 'Int128' (aka 'struct Int128') with an expression of incompatible type '__int128_t' (aka 
>> '__int128')
>>       63 |     Int128 old = *ptr_align;
>>          |            ^     ~~~~~~~~~~
>>    host/include/generic/host/atomic128-cas.h.inc:65:62: error: invalid operands to 
>> binary expression ('Int128' (aka 'struct Int128') and 'Int128')
>>       65 |     while (!__atomic_compare_exchange_n(ptr_align, &old, old | val, true,
>>          |                                                          ~~~ ^ ~~~
>>    1 warning and 6 errors generated.
>>
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> 
> And what of the CONFIG_TCG_INTERPRETER test that already exists in int128.h?
> 
> There's got to be more to this than that.

If you disable Int128 entirely, then we can't use 
host/include/generic/host/atomic128-cas.h.inc at all.  The bug is within that header, were 
we need to use Int128Alias more, as we already do for atomic16_cmpxchg.

I'll post a fix.


r~