Re: [RFC PATCH] tests/tcg: drop -cpu max from s390x sha512-mvx invocation

[Thomas Huth <thuth@redhat.com>]

On 10/03/2022 12.35, Richard Henderson wrote:
> On 3/10/22 02:21, Thomas Huth wrote:
>> On 10/03/2022 09.36, Thomas Huth wrote:
[...]
>>> However, the error still persists. I now had a closer look by running the 
>>> test with "qemu-s390x" on my z15 machine directly, and all tests are 
>>> failing! The problem happens with both, gcc v11.2.1 and clang v13.0.1. 
>>> The problem goes away (i.e. test works fine) if I compile the code with 
>>> -O1 instead of -O3, or if I use GCC v8.5 instead. I'll try to find out 
>>> more, but as a temporary workaround, we could also switch to -O1 instead 
>>> of -O3.
>>
>> I noticed that the problem does not occur when running the test natively
>> on my s390x box, or via qemu-s390x on my x86 laptop, or when running it
>> via qemu-s390x v6.1.0 on my s390x box. So it's something wrong in the TCG
>> backend, I think, and I was able to bisect the issue down to this commit
>> here:
>>
>> $ git bisect bad
>> 9bca986df88b8ea46b100e3d21cc9e653c83e0b3 is the first bad commit
>> commit 9bca986df88b8ea46b100e3d21cc9e653c83e0b3
>> Author: Richard Henderson <richard.henderson@linaro.org>
>> Date:   Mon Sep 14 20:36:36 2020 -0700
>>
>>      tcg/s390x: Implement TCG_TARGET_HAS_bitsel_vec
>>
>> Richard, could you please have a look? 
[...]> Ok, will look soon.
> Would you pop this into an issue so I don't forget, please?

Sure, I've created a ticket here:

  https://gitlab.com/qemu-project/qemu/-/issues/898

  Thomas