[Bug target/69613] [6 Regression] wrong code with -O and simple 128bit arithmetics and vectors @ aarch64

[ktkachov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69613

--- Comment #5 from ktkachov at gcc dot gnu.org ---
(In reply to Jakub Jelinek from comment #4)
> Yeah,
> (insn 12 11 13 (set (reg:DI 85)
>         (lshiftrt:DI (subreg:DI (reg/v:OI 79 [ v32u128_1 ]) 0)
>             (const_int 1 [0x1]))) pr69613-3.c:19 -1
>      (nil))
> and similar shifts by 1 look just weird when the TImode shift is with
> variable shift count.

Those shifts are ok. They are generated by expand_subword_shift in optabs.c as
part of expand_doubleword_shift.

The problem is that TARGET_SHIFT_TRUNCATION_MASK for aarch64 returns 63 for
word_mode even when SHIFT_COUNT_TRUNCATED is false.
I'll test and post a fix