https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71736
--- Comment #4 from Bernd Edlinger <bernd.edlinger at hotmail dot de> --- gcc -c min.c min.c: In function 'signal_handler': min.c:28:36: warning: implicit declaration of function 'bb_error_msg_and_die' [-Wimplicit-function-declaration] ).__i))) & 0x7f) + 1) >> 1) > 0) ) bb_error_msg_and_die("helper killed by signal %u", (((__extension__ (((union { ^~~~~~~~~~~~~~~~~~~~ min.c:45:25: warning: implicit declaration of function 'vfork'; did you mean 'fork'? [-Wimplicit-function-declaration] pid_t bb__xvfork_pid = vfork(); ^~~~~ fork min.c:49:2: error: definition in block 6 does not dominate use in block 7 } ^ for SSA_NAME: ptr_to_globals.0_11 in statement: # .MEM_25 = VDEF <.MEM_22> ptr_to_globals.0_11->helper_pid = _24; min.c:49:2: internal compiler error: verify_ssa failed 0xd792cc verify_ssa(bool, bool) ../../gcc-trunk/gcc/tree-ssa.c:1039 0xaa24ed execute_function_todo ../../gcc-trunk/gcc/passes.c:1971 0xaa34eb execute_todo ../../gcc-trunk/gcc/passes.c:2016 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.