Hello, [1] says "Although any non-initialized subobjects are initialized implicitly, implicit initialization of a subobject never overrides explicit initialization of the same subobject if it appeared earlier in the initializer list (choose clang to observe the correct output)". There's a sample program attached on the website at [1] around the statement, and the behaviour clearly differs between gcc and clang. ----------- This difference is affecting Mesa builds with gcc, because Mesa utilizes such subobject-init-override patterns. One such instance is within the function blorp_params_get_clear_kernel_fs listed at [2]. The relevant parts were extracted and built into a small test program, available at [3] (for gcc) and [4] (for clang) gcc prints: "" '' clang prints: "blorp" 'b' clang does spit out warnings about -Winitializer-overrides before allowing the compilation to succeed. According to the cppref website, Mesa's usage is correct, and it is gcc that's ignoring the fact that the subobject was previously *explicitly* initialized. The C spec says: "The initialization shall occur in initializer list order, each initializer provided for a particular subobject overriding any previously listed initializer for the same subobject;170) all subobjects that are not initialized explicitly are subject to default initialization." Is there a way to force gcc to behave as clang does? If not, could you please help determine who exactly is at fault here and must receive a change/bug request, if needed? Thank you, Amol ----------------------------- [1] https://en.cppreference.com/w/c/language/struct_initialization [2] https://gitlab.freedesktop.org/mesa/mesa/-/blob/main/src/intel/blorp/blorp_clear.c?ref_type=heads [3] https://godbolt.org/z/env53Wq9M [4] https://godbolt.org/z/8TMfbb5Ef
