[Bug target/69577] [5/6 Regression] wrong code with -fno-forward-propagate -mavx and 128bit arithmetics since r215450

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69577

--- Comment #5 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Vladimir Makarov from comment #4)

> I believe machine-dependent code is more responsible for it.  I remember
> some discussion of it.  LRA follows RTL semantics where insn
> 
> (set (subreg reg 0) ...)
> 
> sets only part of subreg but x86-64 insn implementing it changes all reg.

Please see PR 67609 for the discussion.