[Dropping coreutils from CC.] Pádraig Brady wrote: > Actually different -Wmaybe-initialized warnings can trigger at various > optimization levels.
That's an interesting observation. Indeed, compiling a testdir of all of gnulib at various optimization levels with gcc 13.1.0, through commands like this: export CPPFLAGS=-Wall mkdir build-O0; cd build-O0; CFLAGS=-O0 ../configure 2>&1 | tee log1; make 2>&1 | tee log2; cd .. mkdir build-O1; cd build-O1; CFLAGS=-O1 ../configure 2>&1 | tee log1; make 2>&1 | tee log2; cd .. mkdir build-O2; cd build-O2; CFLAGS=-O2 ../configure 2>&1 | tee log1; make 2>&1 | tee log2; cd .. mkdir build-O3; cd build-O3; CFLAGS=-O3 ../configure 2>&1 | tee log1; make 2>&1 | tee log2; cd .. mkdir build-Os; cd build-Os; CFLAGS=-Os ../configure 2>&1 | tee log1; make 2>&1 | tee log2; cd .. mkdir build-Og; cd build-Og; CFLAGS=-Og ../configure 2>&1 | tee log1; make 2>&1 | tee log2; cd .. I get warnings at various levels: * All optimizations levels: ../../gllib/astrxfrm.c:159:19: warning: pointer 'result' may be used after 'realloc' [-Wuse-after-free] ../../gllib/get-rusage-data.c:354:1: warning: 'get_rusage_data_via_iterator' defined but not used [-Wunused-function] ../../gllib/hamt.c:201:1: warning: 'init_element' defined but not used [-Wunused-function] ../../gltests/../gllib/stack.h:75:24: warning: 'stack_current_base' defined but not used [-Wunused-function] * -O0 only: ../../gllib/nstrftime.c:148:31: warning: 'memset' specified size 18446744073709551615 exceeds maximum object size 9223372036854775807 [-Wstringop-overflow=] ../../gllib/nstrftime.c:147:32: warning: 'memset' specified size 18446744073709551615 exceeds maximum object size 9223372036854775807 [-Wstringop-overflow=] * -O1, -O2, -O3 only: ../../gllib/vasnprintf.c:945:26: warning: argument 1 value '18446744073709551615' exceeds maximum object size 9223372036854775807 [-Walloc-size-larger-than=] * -O1, -O2, -O3, -Os only: ../../gllib/vasnprintf.c:1392:10: warning: 'e' may be used uninitialized [-Wmaybe-uninitialized] ../../gllib/vasnprintf.c:1410:10: warning: 'e' may be used uninitialized [-Wmaybe-uninitialized] * -O1, -O2, -O3, -Og, -Os only: ../../gllib/getndelim2.c:191:23: warning: 'c' may be used uninitialized [-Wmaybe-uninitialized] * -O2, -O3, -Os only: ../../gllib/astrxfrm.c:177:1: warning: function may return address of local variable [-Wreturn-local-addr] * -O2, -O3 only: ../../gllib/canonicalize.c:385:33: warning: 'end_idx' may be used uninitialized [-Wmaybe-uninitialized] * -Og only: ../../gllib/bitset/list.c:458:22: warning: 'tmp' may be used uninitialized [-Wmaybe-uninitialized] I've seen many of these warnings and regularly ignored them. But one of these warnings points to a real bug (in astrxfrm.c), that was sitting there since the beginning. The lesson I learn from this (once again — I already knew it before...) that it is important to have a warning-free build on glibc systems. Bruno
