Re: [PATCH] tcg/s390x: fix constraint for 32-bit TSTEQ/TSTNE

[Paolo Bonzini <pbonzini@redhat.com>]

On 10/17/24 12:00, Peter Maydell wrote:
> On Thu, 17 Oct 2024 at 10:14, Paolo Bonzini <pbonzini@redhat.com> wrote:
>>
>> 32-bit TSTEQ and TSTNE is subject to the same constraints as
>> for 64-bit, but setcond_i32 and negsetcond_i32 were incorrectly
>> using TCG_CT_CONST ("i") instead of TCG_CT_CONST_CMP ("C").
>>
>> Adjust the constraint and make tcg_target_const_match use the
>> same sequence as tgen_cmp2: first check if the constant is a
>> valid operand for TSTEQ/TSTNE, then accept everything for 32-bit
>> non-test comparisons, finally check if the constant is a valid
>> operand for 64-bit non-test comparisons.
>>
>> Reported-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> 
> Should this cc stable? Does it cause any current problems?
> (AIUI the x86 target changes in your pending pullreq do
> trigger this.)

Yeah, that's a good idea.  It's probably possible to construct x86 code 
that triggers it (I'm surprised it wasn't found until now).

Paolo