[Bug target/82735] _mm256_zeroupper does not invalidate previously computed registers

[noloader at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82735

--- Comment #6 from Jeffrey Walton <noloader at gmail dot com> ---
Add 9.3 to the know to fail list:

$ gcc --version
gcc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0
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