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From: Nick Desaulniers <ndesaulniers@google.com>
To: sfr@canb.auug.org.au
Cc: axboe@kernel.dk, josef@toxicpanda.com, libaokun1@huawei.com,
	 linux-kernel@vger.kernel.org, linux-next@vger.kernel.org,
	 Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	llvm@lists.linux.dev
Subject: Re: linux-next: build failure while building Linus' tree
Date: Thu,  9 Sep 2021 15:50:35 -0700	[thread overview]
Message-ID: <20210909225035.3990728-1-ndesaulniers@google.com> (raw)
In-Reply-To: <20210909182525.372ee687@canb.auug.org.au>

+ Rasmus

This was introduced in
commit f0907827a8a91 ("compiler.h: enable builtin overflow checkers and add
fallback code")
which added division using the `/` operator, which is problematic when checking
for overflows of 64b operands on 32b targets.

We'll probably need helpers from linux/math64.h and some combination of
__builtin_choose_expr/__builtin_types_compatible_p.

That will help us fix another compiler bug for older clang releases, too.
https://github.com/ClangBuiltLinux/linux/issues/1438.

  reply	other threads:[~2021-09-09 22:50 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-09  8:25 linux-next: build failure while building Linus' tree Stephen Rothwell
2021-09-09 22:50 ` Nick Desaulniers [this message]
2021-09-09 22:50   ` Nick Desaulniers
2021-09-10 22:02   ` Nick Desaulniers
2021-09-10 22:02     ` Nick Desaulniers
2021-09-10 22:17     ` Nick Desaulniers
2021-09-10 22:17       ` Nick Desaulniers
2021-09-10 22:26       ` Nick Desaulniers
2021-09-10 22:26         ` Nick Desaulniers
2021-09-10 22:34         ` Nick Desaulniers
2021-09-10 22:34           ` Nick Desaulniers

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