From: Borislav Petkov <bp@alien8.de>
To: Nathan Chancellor <nathan@kernel.org>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>,
llvm@lists.linux.dev, open list <linux-kernel@vger.kernel.org>,
Linux-Next Mailing List <linux-next@vger.kernel.org>,
lkft-triage@lists.linaro.org, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: Re: x86/include/asm/arch_hweight.h:49:15: error: invalid input size for constraint 'D'
Date: Tue, 7 Feb 2023 17:44:18 +0100 [thread overview]
Message-ID: <Y+J/4kGuIqb8qeob@zn.tnic> (raw)
In-Reply-To: <Y+J+UQ1vAKr6RHuH@dev-arch.thelio-3990X>
On Tue, Feb 07, 2023 at 09:37:37AM -0700, Nathan Chancellor wrote:
> Clang does its semantic analysis before optimization, so it cannot dead
> code eliminate that chunk before it checks the validity of the asm
> constraints, that is just how the pipeline is structured as far as I
> understand it. That is one of the biggest and longest standing
> differences between clang and GCC that we know about, the upstream link
> in the issue below has some more info.
>
> https://github.com/ClangBuiltLinux/linux/issues/3
>
> I am not super familiar with the internal details of LLVM and clang as
> other folks are though so I could be wrong or missing something :)
Thanks and wow, that's issue #3. Like wow that's old. And reading Nick's
text, it sure does sound like that's the one.
Fun.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
prev parent reply other threads:[~2023-02-07 16:44 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-07 7:57 x86/include/asm/arch_hweight.h:49:15: error: invalid input size for constraint 'D' Naresh Kamboju
2023-02-07 16:28 ` Nathan Chancellor
2023-02-07 16:30 ` Borislav Petkov
2023-02-07 16:37 ` Nathan Chancellor
2023-02-07 16:44 ` Borislav Petkov [this message]
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