[Bug tree-optimization/59644] [4.9 Regression] r206243 miscompiles Linux kernel

["trippels at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59644

--- Comment #8 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
>From the printk.i:
38333  int printk_emit(int facility, int level,
38334       const char *dict, size_t dictlen,
38335       const char *fmt, ...)
38336 {
38337  va_list args;
38338  int r;
38339
38340  __builtin_va_start(args,fmt);
38341  r = vprintk_emit(facility, level, dict, dictlen, fmt, args);
38342  __builtin_va_end(args);
38343
38344  return r;
38345 }
38346 ;
38347 # 1676 "kernel/printk/printk.c"
38348  int printk(const char *fmt, ...)
38349 {
38350  va_list args;
38351  int r;
38352 # 1689 "kernel/printk/printk.c"
38353  __builtin_va_start(args,fmt);
38354  r = vprintk_emit(0, -1, ((void *)0), 0, fmt, args);
38355  __builtin_va_end(args);
38356
38357  return r;
38358 }
38359 ;

dump_stack_set_arch_desc is also a call wrapped by __builtin_va_start
__builtin_va_end.