[Bug libstdc++/99552] New: FAIL: 29_atomics/atomic/wait_notify/bool.cc (test for excess errors)

[Bug libstdc++/99552] New: FAIL: 29_atomics/atomic/wait_notify/bool.cc (test for excess errors)

[danglin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99552

            Bug ID: 99552
           Summary: FAIL: 29_atomics/atomic/wait_notify/bool.cc (test for
                    excess errors)
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: danglin at gcc dot gnu.org
  Target Milestone: ---
              Host: hppa2.0w-hp-hpux11.11
            Target: hppa2.0w-hp-hpux11.11
             Build: hppa2.0w-hp-hpux11.11

spawn /test/gnu/gcc/objdir/./gcc/xg++ -shared-libgcc
-B/test/gnu/gcc/objdir/./gc
c -nostdinc++ -L/test/gnu/gcc/objdir/hppa2.0w-hp-hpux11.11/libstdc++-v3/src
-L/t
est/gnu/gcc/objdir/hppa2.0w-hp-hpux11.11/libstdc++-v3/src/.libs
-L/test/gnu/gcc/
objdir/hppa2.0w-hp-hpux11.11/libstdc++-v3/libsupc++/.libs
-B/opt/gnu/gcc/gcc-11/
hppa2.0w-hp-hpux11.11/bin/ -B/opt/gnu/gcc/gcc-11/hppa2.0w-hp-hpux11.11/lib/
-isy
stem /opt/gnu/gcc/gcc-11/hppa2.0w-hp-hpux11.11/include -isystem
/opt/gnu/gcc/gcc
-11/hppa2.0w-hp-hpux11.11/sys-include -fchecking=1
-B/test/gnu/gcc/objdir/hppa2.
0w-hp-hpux11.11/./libstdc++-v3/src/.libs -fmessage-length=0 -fno-show-column -g
-O2 -DLOCALEDIR="." -nostdinc++
-I/test/gnu/gcc/objdir/hppa2.0w-hp-hpux11.11/lib
stdc++-v3/include/hppa2.0w-hp-hpux11.11
-I/test/gnu/gcc/objdir/hppa2.0w-hp-hpux1
1.11/libstdc++-v3/include -I/test/gnu/gcc/gcc/libstdc++-v3/libsupc++
-I/test/gnu/gcc/gcc/libstdc++-v3/include/backward
-I/test/gnu/gcc/gcc/libstdc++-v3/testsuite/util
/test/gnu/gcc/gcc/libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/bool.cc
-std=gnu++2a -pthread -L../../libatomic/.libs -latomic
-fdiagnostics-plain-output ./libtestc++.a
-L/test/gnu/gcc/objdir/hppa2.0w-hp-hpux11.11/libstdc++-v3/src/filesystem/.libs
-lm -o ./bool.exe
/test/gnu/gcc/gcc/libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/bool.cc:64:
warning: alignment (64) for _ZZNSt8__detail9__waiters6_S_forEPKvE3__w exceeds
maximum alignment for global common data.  Using 32
output is:
/test/gnu/gcc/gcc/libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/bool.cc:64:
warning: alignment (64) for _ZZNSt8__detail9__waiters6_S_forEPKvE3__w exceeds
maximum alignment for global common data.  Using 32

FAIL: 29_atomics/atomic/wait_notify/bool.cc (test for excess errors)
Excess errors:
/test/gnu/gcc/gcc/libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/bool.cc:64:
warning: alignment (64) for _ZZNSt8__detail9__waiters6_S_forEPKvE3__w exceeds
maximum alignment for global common data.  Using 32

Similar fails:
FAIL: 29_atomics/atomic/wait_notify/bool.cc (test for excess errors)
FAIL: 29_atomics/atomic/wait_notify/generic.cc (test for excess errors)
FAIL: 29_atomics/atomic/wait_notify/pointers.cc (test for excess errors)
FAIL: 29_atomics/atomic_flag/wait_notify/1.cc (test for excess errors)
FAIL: 29_atomics/atomic_float/wait_notify.cc (test for excess errors)
FAIL: 29_atomics/atomic_integral/wait_notify.cc (test for excess errors)
FAIL: 29_atomics/atomic_ref/wait_notify.cc (test for excess errors)
FAIL: 30_threads/barrier/arrive.cc (test for excess errors)
FAIL: 30_threads/barrier/arrive_and_drop.cc (test for excess errors)
FAIL: 30_threads/barrier/arrive_and_wait.cc (test for excess errors)
FAIL: 30_threads/barrier/completion.cc (test for excess errors)
FAIL: 30_threads/condition_variable_any/stop_token/wait_on.cc (test for excess
errors)
FAIL: 30_threads/jthread/3.cc (test for excess errors)
FAIL: 30_threads/jthread/jthread.cc (test for excess errors)
FAIL: 30_threads/latch/3.cc (test for excess errors)

Usually, I add "-fno-common" to avoid these warnings on hppa*-*-hpux*.

[Bug libstdc++/99552] FAIL: 29_atomics/atomic/wait_notify/bool.cc (test for excess errors)

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99552

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2021-03-11
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=99306

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to John David Anglin from comment #0)
> FAIL: 29_atomics/atomic/wait_notify/bool.cc (test for excess errors)
> Excess errors:
> /test/gnu/gcc/gcc/libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/bool.
> cc:64: warning: alignment (64) for _ZZNSt8__detail9__waiters6_S_forEPKvE3__w
> exceeds maximum alignment for global common data.  Using 32

See also PR 99306

> Usually, I add "-fno-common" to avoid these warnings on hppa*-*-hpux*.

Isn't that redundant for C++, and on by default for C in GCC 11 anyway?

[Bug libstdc++/99552] FAIL: 29_atomics/atomic/wait_notify/bool.cc (test for excess errors)

[dave.anglin at bell dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99552

--- Comment #2 from dave.anglin at bell dot net ---
On 2021-03-11 10:08 a.m., redi at gcc dot gnu.org wrote:
>> Usually, I add "-fno-common" to avoid these warnings on hppa*-*-hpux*.
> Isn't that redundant for C++, and on by default for C in GCC 11 anyway?
You are correct - it doesn't work to suppress warning.  However,
ASM_OUTPUT_ALIGNED_COMMON
is still being used.

[Bug libstdc++/99552] FAIL: 29_atomics/atomic/wait_notify/bool.cc (test for excess errors)

[dave.anglin at bell dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99552

--- Comment #3 from dave.anglin at bell dot net ---
On 2021-03-11 10:08 a.m., redi at gcc dot gnu.org wrote:
>> FAIL: 29_atomics/atomic/wait_notify/bool.cc (test for excess errors)
>> Excess errors:
>> /test/gnu/gcc/gcc/libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/bool.
>> cc:64: warning: alignment (64) for _ZZNSt8__detail9__waiters6_S_forEPKvE3__w
>> exceeds maximum alignment for global common data.  Using 32
> See also PR 99306
Cache line alignment is variable on hppa and it can be up to 128.  The maximum
alignment for global common data
is smaller than the cache line alignment on some machines.

[Bug libstdc++/99552] FAIL: 29_atomics/atomic/wait_notify/bool.cc (test for excess errors)

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99552

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
That's useful to know, thanks.

The current header-based implementation is experimental and those aligned
objects will be moved into the library at some point, where we can probably
control their placement and alignment more precisely.

In the meantime, I think we want a macro in config/os/*/os_defines.h that says
whether we should try to over-align them. If we don't do it, performance will
suffer because of false sharing, but it won't affect correctness.