[Bug sanitizer/63927] AddressSanitizer painfully slow on ppc64

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63927

--- Comment #1 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
The numbers above are seconds.

Perf shows:
  29.44%  a.out  libgcc_s.so.1       [.] uw_update_context_1
  13.08%  a.out  libasan.so.2.0.0    [.] __sanitizer::mem_is_zero(char const*,
unsigned long)
  11.40%  a.out  libgcc_s.so.1       [.] execute_cfa_program
   5.61%  a.out  libpthread-2.18.so  [.] pthread_mutex_unlock
   5.26%  a.out  libc-2.18.so        [.] memcpy
   4.90%  a.out  libgcc_s.so.1       [.] _Unwind_IteratePhdrCallback
   4.07%  a.out  libasan.so.2.0.0    [.] __asan_region_is_poisoned
   3.33%  a.out  libpthread-2.18.so  [.] pthread_mutex_lock
   2.51%  a.out  libgcc_s.so.1       [.] uw_frame_state_for
   2.36%  a.out  libc-2.18.so        [.] memset
   1.53%  a.out  libasan.so.2.0.0    [.] __interceptor_strlen
   1.51%  a.out  libgcc_s.so.1       [.] read_encoded_value_with_base
   1.38%  a.out  libasan.so.2.0.0    [.] __asan_memcpy
   0.95%  a.out  libasan.so.2.0.0    [.] __asan_memset