Re: [PATCH] x86/asm: Fix inline asm call constraints for GCC 4.4

Arnd Bergmann
2017-09-29T15:29:37Z

On Fri, Sep 29, 2017 at 12:51 AM, Ingo Molnar <mingo@kernel.org> wrote:
>
> * Linus Torvalds <torvalds@linux-foundation.org> wrote:
>
>> On Thu, Sep 28, 2017 at 2:58 PM, Josh Poimboeuf <jpoimboe@redhat.com> wrote:
>> The kernel test robot report looked to be ignored as a "gcc-4.4 is too
>> old to worry about" thing. [...]
>
> No, and sorry if my first reply grumbling about how old GCC 4.4 is sounded that
> way! We have to live with compiler bugs no matter how old the compiler is, the
> release cycles are decoupled to such a degree and external tooling propagates with
> such high latencies that that's the only sane thing to do.
>
> We also officially support GCC 3.2 and later compilers. Had this regression not
> been resolved within a week or so I was fully ready to queue up a revert commit,
> no questions asked.

FWIW, we had a discussion about which compiler versions actually still work
earlier this year: We concluded that gcc-4.0 and earlier have been broken
for a while without anyone caring. gcc-4.1 support is kept working in certain
configurations primarily due to Geert using it for build testing, but my tests
across multiple architectures showed that gcc-4.3 is needed on most
other architectures already. Some architectures need even newer ones, and
some features need compiler support that was added much later of course.

Arnd