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From: Nick Desaulniers <>
To: "Jason A. Donenfeld" <>
	Linux Kbuild mailing list <>,
	LKML <>
Subject: Re: gcc 5 & 6 & others already out of date?
Date: Thu, 13 Oct 2022 14:08:22 -0700	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Wed, Oct 12, 2022 at 6:37 PM Jason A. Donenfeld <> wrote:
> Hi,
> I've been working on a (still in development) patch that tries to
> apply a few compile-time constant folding tricks to a widely used
> library function, so I wanted to make sure my trickery worked across
> all supported gcc versions for as many call sites as possible.

I'd imagine the kernel's inconsistent use of -ffreestanding per
architecture would be a blocker, if by library function you're
referring to a symbol that would typically be provided by the libc?

Do you have more info about what the specific issue you've observed is?

> Naturally, this means allyesconfig builds on the monster box.
> So all went well with a recent gcc and with clang. Then I tried gcc 5
> and gcc 6, and it wasn't fine. But it wasn't not fine because of my
> new code -- that all compiled just fine. Rather, it wasn't fine
> because of a modicum of other odd errors and fatal warnings
> throughout. I tried this with gcc 5 and gcc 6 and then got bored. I
> could test more versions need be. And I guess I could submit bug
> reports or write patches or work on fixing all those, if I actually
> cared about it. But I don't really care about it, and apparently
> neither does anybody else, because this isn't brand new breakage. And
> this all got me thinking...

Are the defconfigs totally broken with gcc-5 and gcc-6 and no one has noticed?

I wonder what versions of GCC KernelCI and linux kernel robot are testing with?

We have to maintain CI for all supported clang versions. You can see a
2D slice of our 5D build matrix:
"I've never seen so much red in the galaxy!" "Hey, get back to work!"

We'd like to have the large window of supported versions that GCC
currently has; Clang's release cycle is also different from GCC's
though.  I wouldn't point to clang's smaller version support window as
justification for GCC; we'd rather be more like GCC in that sense, not
the other way round!
~Nick Desaulniers

  parent reply	other threads:[~2022-10-13 21:08 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-13  1:36 gcc 5 & 6 & others already out of date? Jason A. Donenfeld
2022-10-13 12:22 ` David Laight
2022-10-13 12:59 ` Mark Brown
2022-10-13 15:23   ` Jason A. Donenfeld
2022-10-13 16:18     ` Willy Tarreau
2022-10-14  4:28       ` David Laight
2022-10-14  5:27         ` Willy Tarreau
2022-10-13 16:26     ` Mark Brown
2022-10-13 16:37       ` Jason A. Donenfeld
2022-10-13 16:51         ` Willy Tarreau
2022-10-13 17:16         ` Mark Brown
2022-10-13 18:38           ` Florian Weimer
2022-10-13 20:23             ` Mark Brown
2022-10-14  6:15               ` Florian Weimer
2022-10-13 18:39     ` Florian Weimer
2022-10-13 21:03       ` Nick Desaulniers
2022-10-14  6:37         ` Florian Weimer
2022-10-13 21:08 ` Nick Desaulniers [this message]
2022-10-14  1:31   ` Jason A. Donenfeld
2022-10-14 11:13   ` Mark Brown

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