c, c++: Allow ignoring -Winit-self through pragmas [PR105593]
As mentioned in the PR, various x86 intrinsics need to return
an uninitialized vector. Currently they use self initialization
to avoid -Wuninitialized warnings, which works fine in C, but
doesn't work in C++ where -Winit-self is enabled in -Wall.
We don't have an attribute to mark a variable as knowingly
uninitialized (the uninitialized attribute exists but means
something else, only in the -ftrivial-auto-var-init context),
and trying to suppress either -Wuninitialized or -Winit-self
inside of the _mm_undefined_ps etc. intrinsic definitions
doesn't work, one needs to currently disable through pragmas
-Wuninitialized warning at the point where _mm_undefined_ps etc.
result is actually used, but that goes against the intent of
those intrinsics.
The -Winit-self warning option actually doesn't do any warning,
all we do is record a suppression for -Winit-self if !warn_init_self
on the decl definition and later look that up in uninit pass.
The following patch changes those !warn_init_self tests which
are true only based on the command line option setting, not based
on GCC diagnostic pragma overrides to
!warning_enabled_at (DECL_SOURCE_LOCATION (decl), OPT_Winit_self)
such that it takes them into account.
2023-01-16 Jakub Jelinek <jakub@redhat.com>
PR c++/105593
gcc/c/
* c-parser.cc (c_parser_initializer): Check warning_enabled_at
at the DECL_SOURCE_LOCATION (decl) for OPT_Winit_self instead
of warn_init_self.
gcc/cp/
* decl.cc (cp_finish_decl): Check warning_enabled_at
at the DECL_SOURCE_LOCATION (decl) for OPT_Winit_self instead
of warn_init_self.
gcc/testsuite/
* c-c++-common/Winit-self3.c: New test.
* c-c++-common/Winit-self4.c: New test.
* c-c++-common/Winit-self5.c: New test.