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authorMatheus Tavares Bernardino <quic_mathbern@quicinc.com>2023-03-13 15:58:19 -0300
committerJuan Quintela <quintela@redhat.com>2023-03-16 16:07:07 +0100
commitd84a78d15d3af9ff28ceec6906a4b101bd545b55 (patch)
tree68b03cf41f925795e8ca59e711326959e3313664
parenta5382214d8b099bb2fe60b206097567762861800 (diff)
downloadfocaccia-qemu-d84a78d15d3af9ff28ceec6906a4b101bd545b55.tar.gz
focaccia-qemu-d84a78d15d3af9ff28ceec6906a4b101bd545b55.zip
migration/xbzrle: use ctz64 to avoid undefined result
__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_mathbern@quicinc.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
-rw-r--r--migration/xbzrle.c5
1 files 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;