[Bug target/68620] ICE on gcc.target/arm/attr-neon-fp16.c

[clyon at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68620

--- Comment #1 from Christophe Lyon <clyon at gcc dot gnu.org> ---
The problem happens when trying to extract subregs from V4HF.

On big-endian, CANNOT_CHANGE_MODE_CLASS returns 1, which at some point makes
xpart = operand_subword (x, i, 1, mode); (in emit_move_multi_word)
return NULL in xpart, later trigging the assert.