https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94940
--- Comment #3 from Martin Liška <marxin at gcc dot gnu.org> --- Created attachment 48436 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48436&action=edit Original test-case $ gcc -c -O2 -Werror=array-bounds intelvf2.i -m32 intelvf2.i: In function ‘intelvf_mbox_poll’: intelvf2.i:2658:13: error: array subscript i is outside array bounds of ‘uint32_t[0]’ {aka ‘unsigned int[]’} [-Werror=array-bounds] 2658 | msg->dword[i] = ( { volatile uint32_t *_io_addr = ( ( volatile uint32_t * ) ( intptr_t ) (intel->regs + intel->mbox.mem + ( i * sizeof ( msg->dword[0] ) )) ); uint32_t _data = readl ( _io_addr ); do { if ( ( 0 & 8 ) ) { dbg_printf ( "[" "MEM" " %08lx] => %0" "8" "llx\n", io_to_bus ( _io_addr ), ( unsigned long long ) _data ); } } while ( 0 ); _data; } ) | ~~~~~~~~~~^~~ intelvf2.i:2615:11: note: while referencing ‘dword’ 2615 | uint32_t dword[0]; | ^~~~~ intelvf2.i:2666:20: note: defined here ‘msg’ 2666 | union intelvf_msg msg; | ^~~ intelvf2.i: In function ‘intelvf_mbox_wait’: intelvf2.i:2658:13: error: array subscript i is outside array bounds of ‘uint32_t[0]’ {aka ‘unsigned int[]’} [-Werror=array-bounds] 2658 | msg->dword[i] = ( { volatile uint32_t *_io_addr = ( ( volatile uint32_t * ) ( intptr_t ) (intel->regs + intel->mbox.mem + ( i * sizeof ( msg->dword[0] ) )) ); uint32_t _data = readl ( _io_addr ); do { if ( ( 0 & 8 ) ) { dbg_printf ( "[" "MEM" " %08lx] => %0" "8" "llx\n", io_to_bus ( _io_addr ), ( unsigned long long ) _data ); } } while ( 0 ); _data; } ) | ~~~~~~~~~~^~~ intelvf2.i:2615:11: note: while referencing ‘dword’ 2615 | uint32_t dword[0]; | ^~~~~ intelvf2.i:2666:20: note: defined here ‘msg’ 2666 | union intelvf_msg msg; | ^~~ cc1: some warnings being treated as errors
