From: Richard Biener <richard.guenther@gmail.com>
To: Jason Merrill <jason@redhat.com>
Cc: Aldy Hernandez <aldyh@redhat.com>,
GCC Mailing List <gcc@gcc.gnu.org>,
"MacLeod, Andrew" <amacleod@redhat.com>
Subject: Re: 1.76% performance loss in VRP due to inlining
Date: Tue, 30 Apr 2024 21:15:25 +0200 [thread overview]
Message-ID: <179E65E4-33E7-45F1-A7B3-755CA434D037@gmail.com> (raw)
In-Reply-To: <CADzB+2=ptBaKFMj3zJgh-UM9Zuh0B8_RRmfVZhBESRFhkGQspA@mail.gmail.com>
> Am 30.04.2024 um 21:11 schrieb Jason Merrill via Gcc <gcc@gcc.gnu.org>:
>
> On Fri, Apr 26, 2024 at 5:44 AM Aldy Hernandez via Gcc <gcc@gcc.gnu.org> wrote:
>>
>> In implementing prange (pointer ranges), I have found a 1.74% slowdown
>> in VRP, even without any code path actually using the code. I have
>> tracked this down to irange::get_bitmask() being compiled differently
>> with and without the bare bones patch. With the patch,
>> irange::get_bitmask() has a lot of code inlined into it, particularly
>> get_bitmask_from_range() and consequently the wide_int_storage code.
> ...
>> +static irange_bitmask
>> +get_bitmask_from_range (tree type,
>> + const wide_int &min, const wide_int &max)
> ...
>> -irange_bitmask
>> -irange::get_bitmask_from_range () const
>
> My guess is that this is the relevant change: the old function has
> external linkage, and is therefore interposable, which inhibits
> inlining. The new function has internal linkage, which allows
> inlining.
>
> Relatedly, I wonder if we want to build GCC with -fno-semantic-interposition?
I guess that’s a good idea, though it’s already implied when doing LTO bootstrap and building cc1 and friends? (But not for libgccjit?)
Richard
>
> Jason
>
next prev parent reply other threads:[~2024-04-30 19:15 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-26 9:42 Aldy Hernandez
2024-04-30 7:57 ` Richard Biener
2024-04-30 8:21 ` Aldy Hernandez
2024-04-30 8:53 ` Martin Jambor
2024-04-30 19:09 ` Jason Merrill
2024-04-30 19:15 ` Richard Biener [this message]
2024-04-30 21:48 ` Building libgccjit with -fno-semantic-interposition? ( was Re: 1.76% performance loss in VRP due to inlining) David Malcolm
2024-05-02 7:40 ` Andrea Corallo
2024-04-30 19:22 ` 1.76% performance loss in VRP due to inlining Jakub Jelinek
2024-04-30 21:37 ` Jason Merrill
2024-05-03 8:55 ` Aldy Hernandez
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