[Bug target/104976] [avx512fp16] lowpart_subreg return NULL_RTX cause ICE

[crazylht at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104976

Hongtao.liu <crazylht at gmail dot com> changed:

           What    |Removed                     |Added
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             Target|                            |x86_64-*-* i?86-*-*
           Keywords|                            |ice-on-valid-code

--- Comment #1 from Hongtao.liu <crazylht at gmail dot com> ---
The walkround in the backend is force_reg operand[1] before lowpart_subreg to
avoid NULL_RTX.