[Bug middle-end/99612] Remove "#pragma GCC system_header" from atomic file to warn on incorrect memory order
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99612 Martin Sebor changed: What|Removed |Added Resolution|--- |FIXED Status|ASSIGNED|RESOLVED --- Comment #6 from Martin Sebor --- Fixed for GCC 12. The fix and its dependencies are too intrusive not backport to GCC 11.
[Bug middle-end/99612] Remove "#pragma GCC system_header" from atomic file to warn on incorrect memory order
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99612 --- Comment #5 from CVS Commits --- The master branch has been updated by Martin Sebor : https://gcc.gnu.org/g:5a431b60d1f221992e5e9f7a5c032df3b5fa35a5 commit r12-6216-g5a431b60d1f221992e5e9f7a5c032df3b5fa35a5 Author: Martin Sebor Date: Tue Jan 4 13:44:23 2022 -0700 Eenable -Winvalid-memory-order for C++ [PR99612]. Resolves: PR middle-end/99612 - Remove "#pragma GCC system_header" from atomic file to warn on incorrect memory order gcc/ChangeLog: PR middle-end/99612 * builtins.c (get_memmodel): Move warning code to gimple-ssa-warn-access.cc. (expand_builtin_atomic_compare_exchange): Same. (expand_ifn_atomic_compare_exchange): Same. (expand_builtin_atomic_load): Same. (expand_builtin_atomic_store): Same. (expand_builtin_atomic_clear): Same. * doc/extend.texi (__atomic_exchange_n): Update valid memory models. * gimple-ssa-warn-access.cc (memmodel_to_uhwi): New function. (struct memmodel_pair): New struct. (memmodel_name): New function. (pass_waccess::maybe_warn_memmodel): New function. (pass_waccess::check_atomic_memmodel): New function. (pass_waccess::check_atomic_builtin): Handle memory model. * input.c (expansion_point_location_if_in_system_header): Return original location if expansion location is in a system header. gcc/testsuite/ChangeLog: PR middle-end/99612 * c-c++-common/pr83059.c: Adjust text of expected diagnostics. * gcc.dg/atomic-invalid-2.c: Same. * gcc.dg/atomic-invalid.c: Same. * c-c++-common/Winvalid-memory-model.c: New test. * g++.dg/warn/Winvalid-memory-model-2.C: New test. * g++.dg/warn/Winvalid-memory-model.C: New test.
[Bug middle-end/99612] Remove "#pragma GCC system_header" from atomic file to warn on incorrect memory order
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99612 Martin Sebor changed: What|Removed |Added Keywords||patch --- Comment #4 from Martin Sebor --- Patch: https://gcc.gnu.org/pipermail/gcc-patches/2021-December/586402.html
[Bug middle-end/99612] Remove "#pragma GCC system_header" from atomic file to warn on incorrect memory order
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99612
--- Comment #3 from Martin Sebor ---
The test case:
$ (set -x && cat pr99612.C && g++ -O2 -S -Wall --std=c++20 -O2 -Wall
-Winvalid-memory-model pr99612.C && g++ -O2 -S -Wall --std=c++20 -O2 -Wall
-Winvalid-memory-model -Wsystem-headers pr99612.C)
+ cat pr99612.C
#include
std::atomic a;
int f() {
auto ret = a.load(std::memory_order_release);
a.store(10, std::memory_order_acquire);
return ret;
}
+ g++ -O2 -S -Wall --std=c++20 -O2 -Wall -Winvalid-memory-model pr99612.C
+ /g++ -O2 -S -Wall --std=c++20 -O2 -Wall -Winvalid-memory-model
-Wsystem-headers pr99612.C
In file included from
/build/gcc-master/x86_64-pc-linux-gnu/libstdc++-v3/include/atomic:41,
from pr99612.C:1:
/build/gcc-master/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/atomic_base.h:
In function ‘int f()’:
/build/gcc-master/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/atomic_base.h:479:31:
warning: invalid memory model for ‘__atomic_load’ [-Winvalid-memory-model]
479 | return __atomic_load_n(&_M_i, int(__m));
| ^
/build/gcc-master/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/atomic_base.h:455:25:
warning: invalid memory model for ‘__atomic_store’ [-Winvalid-memory-model]
455 | __atomic_store_n(&_M_i, __i, int(__m));
| ^
[Bug middle-end/99612] Remove "#pragma GCC system_header" from atomic file to warn on incorrect memory order
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99612 Martin Sebor changed: What|Removed |Added Status|NEW |ASSIGNED Assignee|unassigned at gcc dot gnu.org |msebor at gcc dot gnu.org Known to fail||11.0
[Bug middle-end/99612] Remove "#pragma GCC system_header" from atomic file to warn on incorrect memory order
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99612 Martin Sebor changed: What|Removed |Added Last reconfirmed||2021-03-16 Target Milestone|--- |12.0 See Also||https://gcc.gnu.org/bugzill ||a/show_bug.cgi?id=98871 CC||msebor at gcc dot gnu.org Status|UNCONFIRMED |NEW Component|libstdc++ |middle-end Ever confirmed|0 |1 --- Comment #2 from Martin Sebor --- The root cause is the same as the limitation discussed in pr98871. Warnings issued from the middle end cannot be controlled with sufficient flexibility. The patch attached to the bug should in principle resolve this as well. Let me assign this to myself and handle it for GCC 12. That said, when reporting bugs, please include all the information in the bug we request in https://gcc.gnu.org/bugs/#need, in particular the full test case, the command line options used to compile it, and the compiler output. Links to third party sites are not sufficient (as GCC on Godbolt changes, so might the symptoms).
