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From: "ebotcazou at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/97939] ICE on sparc64 with UBsan for "i + 4096" on long: unrecognizable insn during RTL pass: vregs
Date: Fri, 27 Nov 2020 09:08:23 +0000 [thread overview]
Message-ID: <bug-97939-4-FLmUoxzd4P@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-97939-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97939
--- Comment #6 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
> Not sure how useful this is but all of the following toss the same ICE :
>
> long f(long arg){return arg + 4096;}
>
> long f(long arg){return arg - 4096;}
>
> long f(long arg){return 4096 + arg;}
>
> long f(long arg){return arg - 4096;}
>
> However these work fine :
>
> long f(long arg){return 4096 - arg;}
>
> long f(long arg){return arg * 4096;}
>
> long f(long arg){return 4096 * arg;}
>
> long f(long arg){return arg / 4096;}
>
> etc etc etc as well as other powers of 2.
It's specific to 4096 and additive operations. A look at the assembly
generated for the first 4 without -fsanitize=undefined may give a hunch about
what happens.
next prev parent reply other threads:[~2020-11-27 9:08 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-23 0:48 [Bug target/97939] New: " vincent-gcc at vinc17 dot net
2020-11-23 0:49 ` [Bug target/97939] " vincent-gcc at vinc17 dot net
2020-11-23 8:04 ` ebotcazou at gcc dot gnu.org
2020-11-23 8:04 ` ebotcazou at gcc dot gnu.org
2020-11-26 8:25 ` dclarke at blastwave dot org
2020-11-27 7:55 ` dclarke at blastwave dot org
2020-11-27 9:08 ` ebotcazou at gcc dot gnu.org [this message]
2020-11-27 9:24 ` vincent-gcc at vinc17 dot net
2020-11-27 9:45 ` vincent-gcc at vinc17 dot net
2020-11-28 12:02 ` cvs-commit at gcc dot gnu.org
2020-11-28 12:03 ` cvs-commit at gcc dot gnu.org
2020-11-28 12:03 ` cvs-commit at gcc dot gnu.org
2020-11-28 12:04 ` ebotcazou at gcc dot gnu.org
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