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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/107190] [aarch64] regression with optimization -fexpensive-optimizations
Date: Mon, 10 Oct 2022 16:54:43 +0000 [thread overview]
Message-ID: <bug-107190-4-22dIGDqFa6@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-107190-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107190
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Component|c++ |rtl-optimization
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to vfdff from comment #0)
> This case is simplify from
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107090, and we can see that the
> codegen of function `test_m` has some regression with optimization
> -fexpensive-optimizations, https://gcc.godbolt.org/z/zbKrEox4j
>
> This is because the pass 208t.widening_mul is controlled by
> -fexpensive-optimizations (default on at -O3), it conversion
>
> ```
> m_12 = m_9 + m1_10;
> if (m1_10 > m_12)
> ```
> into
>
> ```
> _17 = .ADD_OVERFLOW (m_9, m1_10);
> m_12 = REALPART_EXPR <_17>;
> _18 = IMAGPART_EXPR <_17>;
> if (_18 != 0)``
This should always be better. If ifcvt.cc does not handle this case, then it
should be improved.
next prev parent reply other threads:[~2022-10-10 16:54 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-09 10:33 [Bug c++/107190] New: " zhongyunde at huawei dot com
2022-10-10 16:54 ` pinskia at gcc dot gnu.org [this message]
2022-10-10 17:31 ` [Bug middle-end/107190] " pinskia at gcc dot gnu.org
2023-05-19 1:22 ` pinskia at gcc dot gnu.org
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