From: Matheus Tavares Bernardino <quic_mathb...@quicinc.com> __builtin_ctzll() produces undefined results when the argument is 0. This can be seen through test-xbzrle, which produces the following warning:
../migration/xbzrle.c:265: runtime error: passing zero to ctz(), which is not a valid argument Replace __builtin_ctzll() with our ctz64() wrapper which properly handles 0. Signed-off-by: Matheus Tavares Bernardino <quic_mathb...@quicinc.com> Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com> Reviewed-by: Juan Quintela <quint...@redhat.com> Signed-off-by: Juan Quintela <quint...@redhat.com> --- migration/xbzrle.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/migration/xbzrle.c b/migration/xbzrle.c index 05366e86c0..21b92d4eae 100644 --- a/migration/xbzrle.c +++ b/migration/xbzrle.c @@ -12,6 +12,7 @@ */ #include "qemu/osdep.h" #include "qemu/cutils.h" +#include "qemu/host-utils.h" #include "xbzrle.h" /* @@ -233,7 +234,7 @@ int xbzrle_encode_buffer_avx512(uint8_t *old_buf, uint8_t *new_buf, int slen, break; } never_same = false; - num = __builtin_ctzll(~comp); + num = ctz64(~comp); num = (num < bytes_to_check) ? num : bytes_to_check; zrun_len += num; bytes_to_check -= num; @@ -262,7 +263,7 @@ int xbzrle_encode_buffer_avx512(uint8_t *old_buf, uint8_t *new_buf, int slen, nzrun_len += 64; break; } - num = __builtin_ctzll(comp); + num = ctz64(comp); num = (num < bytes_to_check) ? num : bytes_to_check; nzrun_len += num; bytes_to_check -= num; -- 2.39.2