From: Andreas Schwab <schwab@linux-m68k.org>
To: Jonathan Wakely via Gcc <gcc@gcc.gnu.org>
Cc: Jakub Jelinek <jakub@redhat.com>,
Jonathan Wakely <jwakely.gcc@gmail.com>,
Theodore Papadopoulo <Theodore.Papadopoulo@inria.fr>
Subject: Re: Enquiry
Date: Mon, 31 Jan 2022 11:25:38 +0100 [thread overview]
Message-ID: <87czk86w2l.fsf@igel.home> (raw)
In-Reply-To: <CAH6eHdSSUYoRV5hPFcCC3D7S1Dg-errdkmJ=9+UY2QS-nTMUbw@mail.gmail.com> (Jonathan Wakely via Gcc's message of "Sun, 30 Jan 2022 11:11:15 +0000")
On Jan 30 2022, Jonathan Wakely via Gcc wrote:
> On Sun, 30 Jan 2022, 10:58 Jakub Jelinek, <jakub@redhat.com> wrote:
>
>> On Sun, Jan 30, 2022 at 10:50:56AM +0000, Jonathan Wakely wrote:
>> > We could put a trap instruction at the end of the function though, which
>> > would make the result a bit less arbitrary.
>> >
>> > I've come around to thinking that's preferable for cases like this.
>>
>> Depends on which exact cases.
>> Because for
>> int foo (int s) { if (s == 123) return 1; }
>> we want to optimize it into
>> return 1;
>> rather than if (s == 123) return 1; else __builtin_trap ();
>> For debugging we have -fsanitize=undefined
>
>
> What if we inserted the trap for -O0?
Note that in C it is not an error to fall through the end of a non-void
function if the caller does not use the return value.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."
next prev parent reply other threads:[~2022-01-31 10:25 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-30 9:47 Enquiry Theodore Papadopoulo
2022-01-30 10:41 ` Enquiry Jakub Jelinek
2022-01-30 10:50 ` Enquiry Jonathan Wakely
2022-01-30 10:58 ` Enquiry Jakub Jelinek
2022-01-30 11:11 ` Enquiry Jonathan Wakely
2022-01-31 9:42 ` Enquiry Jakub Jelinek
2022-01-31 10:25 ` Andreas Schwab [this message]
2022-01-31 10:33 ` Enquiry Jonathan Wakely
2022-01-31 10:16 ` Enquiry Theodore Papadopoulo
2022-01-31 10:23 ` Enquiry Jonathan Wakely
2022-01-30 11:17 ` Enquiry Jonathan Wakely
2022-01-31 9:26 ` Enquiry Theodore Papadopoulo
-- strict thread matches above, loose matches on Subject: below --
2020-09-12 23:44 Enquiry Paul
2009-06-02 13:52 Enquiry Vijay Holimath
[not found] ` <dfa53ad0906021048t7e1c1fc7pf019d1229f529592@mail.gmail.com>
[not found] ` <dfa53ad0906021050p7aa605f2m4a1b6459b7f1f89e@mail.gmail.com>
2009-06-03 10:33 ` Enquiry Vijay
2009-06-02 13:00 Enquiry Vijay Holimath
2006-09-29 13:00 ENQUIRY Dr.Richard Lovward
2000-09-21 20:26 enquiry Adarsh MP
2000-09-22 2:15 ` enquiry Erik Mouw
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