https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71418
Bug ID: 71418 Summary: gcc ICE on x86_64-linux-gnu in min_align_of_type, at stor-layout.c:2402 Product: gcc Version: 7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c Assignee: unassigned at gcc dot gnu.org Reporter: helloqirun at gmail dot com Target Milestone: --- The following invalid code causes an ICE when compiled with the current gcc trunk on x86_64-linux-gnu in both 32-bit and 64-bit modes. It appears to be a 7 regression. $ gcc-trunk -v Using built-in specs. COLLECT_GCC=gcc-trunk COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/7.0.0/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: ../gcc-source-trunk/configure --enable-languages=c,c++,lto --prefix=/usr/local/gcc-trunk --disable-bootstrap Thread model: posix gcc version 7.0.0 20160604 (experimental) [trunk revision 237092] (GCC) $ gcc-trunk abc.c abc.c:1:25: error: lvalue required as increment operand _Alignas (char) ID0 [ ++ 7 ] ; ^~ abc.c:1:1: warning: data definition has no type or storage class _Alignas (char) ID0 [ ++ 7 ] ; ^~~~~~~~ abc.c:1:19: warning: type defaults to ‘int’ in declaration of ‘ID0’ [-Wimplicit-int] _Alignas (char) ID0 [ ++ 7 ] ; ^~~ abc.c:1:1: internal compiler error: tree check: expected class ‘type’, have ‘exceptional’ (error_mark) in min_align_of_type, at stor-layout.c:2402 _Alignas (char) ID0 [ ++ 7 ] ; ^~~~~~~~ 0xe60277 tree_class_check_failed(tree_node const*, tree_code_class, char const*, int, char const*) ../../gcc-source-trunk/gcc/tree.c:9802 0xbaf9dd tree_class_check ../../gcc-source-trunk/gcc/tree.h:3153 0xbaf9dd min_align_of_type(tree_node*) ../../gcc-source-trunk/gcc/stor-layout.c:2402 0x656259 grokdeclarator ../../gcc-source-trunk/gcc/c/c-decl.c:6319 0x65783a start_decl(c_declarator*, c_declspecs*, bool, tree_node*) ../../gcc-source-trunk/gcc/c/c-decl.c:4442 0x6bc0c5 c_parser_declaration_or_fndef ../../gcc-source-trunk/gcc/c/c-parser.c:1963 0x6c6065 c_parser_external_declaration ../../gcc-source-trunk/gcc/c/c-parser.c:1549 0x6c68f9 c_parser_translation_unit ../../gcc-source-trunk/gcc/c/c-parser.c:1430 0x6c68f9 c_parse_file() ../../gcc-source-trunk/gcc/c/c-parser.c:17930 0x728e82 c_common_parse_file() ../../gcc-source-trunk/gcc/c-family/c-opts.c:1064 Please submit a full bug report, with preprocessed source if appropriate. Please include the complete backtrace with any bug report. See <http://gcc.gnu.org/bugs.html> for instructions. $ cat abc.c _Alignas (char) ID0 [ ++ 7 ] ;