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[Bug target/69613] [6 Regression] wrong code with -O and simple 128bit arithmetics and vectors @ aarch64
- From: "ktkachov at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Thu, 04 Feb 2016 13:04:05 +0000
- Subject: [Bug target/69613] [6 Regression] wrong code with -O and simple 128bit arithmetics and vectors @ aarch64
- Auto-submitted: auto-generated
- References: <bug-69613-4 at http dot gcc dot gnu dot org/bugzilla/>
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