[Bug target/112623] [14 Regression] ICE: in emit_move_insn, at expr.cc:4249 with -O -mavx512vl -mavx512fp16 on vector conversion since r14-1707

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112623

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
The vectorizer usually checks the operand mode, like with

      if (insn_data[icode1].operand[0].mode == TYPE_MODE (narrow_vectype))

but yeah, ambiguities are bad here.  When designing these patterns no
such ambiguities existed.  Can't the patterns work out both?  I guess
in the testcases case the issue points to vector lowering failing to
perform this kind of check.  Let me have a quick try.