[Bug c++/111047] New: Un-silenceable note for ABI parameters 64-byte alignment

[Bug c++/111047] New: Un-silenceable note for ABI parameters 64-byte alignment

[gonzalo.gadeschi at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111047

            Bug ID: 111047
           Summary: Un-silenceable note for ABI parameters 64-byte
                    alignment
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gonzalo.gadeschi at gmail dot com
  Target Milestone: ---

Reproducer (https://godbolt.org/z/jvedoeK9E): 

  struct alignas(64) big_t{int x;};
  void f(big_t b) { return; }

outputs:

  <source>: In function 'void f(big_t)':
  <source>:2:6: note: the ABI for passing parameters with 64-byte alignment has
changed in GCC 4.6
      2 | void f(big_t b) { return; }
        |      ^

We are hitting this "note" throughout our code base, which is confusing many of
our developers, and we cannot find a way to silence it.

It would be really helpful to have a flag to disable this "note".

[Bug c++/111047] Un-silenceable note for ABI parameters 64-byte alignment

[schwab@linux-m68k.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111047

--- Comment #1 from Andreas Schwab <schwab@linux-m68k.org> ---
-Wno-abi

[Bug c++/111047] Un-silenceable note for ABI parameters 64-byte alignment

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111047

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2023-08-17
           Keywords|                            |diagnostic
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
More specifically, -Wno-psabi (which is a subset of -Wabi).

The various 'inform' notes in i386.cc that depend on warn_psabi should probably
output "[-Wpsabi]" to make this clear.

[Bug target/111047] Un-silenceable note for ABI parameters 64-byte alignment

[gonzalo.gadeschi at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111047

--- Comment #3 from gnzlbg <gonzalo.gadeschi at gmail dot com> ---
Thank you both. 

> should probably output "[-Wpsabi]" to make this clear.

+1

[Bug target/111047] Un-silenceable note for ABI parameters 64-byte alignment

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111047

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
unfortunately inform() wasn't designed for this, I suppose using warning()
would have been better here.