https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109041
--- Comment #6 from ishikawa,chiaki <ishikawa at yk dot rim.or.jp> --- Created attachment 54610 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54610&action=edit The script to produce the warning in the original report with gcc-11. The source file needs to be in /tmp/sqlite3-preprocessed-2.c Run this script with bash this-script and it will print something like this on my linux PC. Here I put the script into t83.sh: bash ~/Dropbox/TB-DIR/WALL-PATCH-DIR/t83.sh /tmp/sqlite3-preprocessed-2.c: In function ‘posixUnlock’: /tmp/sqlite3-preprocessed-2.c:22632:42: error: self-comparison always evaluates to true [-Werror=tautological-compare] 22632 | sqlite3PendingByte+1==(sqlite3PendingByte+1) | ^~ In function ‘memset’, inlined from ‘pager_playback’ at /tmp/sqlite3-preprocessed-2.c:32113:4: /tmp/sqlite3-preprocessed-2.c:4273:10: error: ‘__builtin_memset’ writing 4 bytes into a region of size 0 overflows the destination [-Werror=stringop-overflow=] 4273 | return __builtin___memset_chk (__dest, __ch, __len, __builtin_object_size (__dest, 0)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /tmp/sqlite3-preprocessed-2.c: In function ‘pager_playback’: /tmp/sqlite3-preprocessed-2.c:32089:30: note: destination object ‘*pPager.pTmpSpace’ of size [0, 9223372036854775807] 32089 | zSuper = (void *) &pPager->pTmpSpace[4]; | ~~~~~~^~~~~~~~~~~ /tmp/sqlite3-preprocessed-2.c:32089:30: note: destination object ‘*pPager.pTmpSpace’ of size [0, 9223372036854775807] cc1: all warnings being treated as errors ishikawa@ip030:/NREF-COMM-CENTRAL/mozilla$
