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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/108370] gcc doesn't merge bitwise-AND if an explicit comparison against 0 is given
Date: Sat, 16 Sep 2023 23:48:45 +0000 [thread overview]
Message-ID: <bug-108370-4-fTrFNTHniC@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-108370-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108370
--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #5)
> _10 = _9 >> 1;
> _11 = (bool) _10;
> if (_11 != 0)
>
>
> Should just be optimized to:
> _t = _9 & 1
> if (_t != 0)
>
> Let me add that to match.
We do handle:
/* Fold ((X << C1) & C2) cmp C3 into (X & (C2 >> C1)) cmp (C3 >> C1)
((X >> C1) & C2) cmp C3 into (X & (C2 << C1)) cmp (C3 << C1). */
next prev parent reply other threads:[~2023-09-16 23:48 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-11 13:47 [Bug c/108370] New: " dhowells at redhat dot com
2023-01-11 14:04 ` [Bug c/108370] " rguenth at gcc dot gnu.org
2023-01-11 14:24 ` rguenth at gcc dot gnu.org
2023-01-11 14:42 ` dhowells at redhat dot com
2023-02-08 20:30 ` [Bug middle-end/108370] " pinskia at gcc dot gnu.org
2023-09-16 22:58 ` pinskia at gcc dot gnu.org
2023-09-16 23:16 ` pinskia at gcc dot gnu.org
2023-09-16 23:48 ` pinskia at gcc dot gnu.org [this message]
2023-09-17 0:35 ` pinskia at gcc dot gnu.org
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