https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65991
Bug ID: 65991 Summary: maybe-unitialized - false positive Product: gcc Version: 4.9.2 Status: UNCONFIRMED Severity: normal Priority: P3 Component: lto Assignee: unassigned at gcc dot gnu.org Reporter: dilyan.palauzov at aegee dot org Target Milestone: --- I have compiled gcc with ../gcc-4.9.2/configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var --enable-threads=posix --enable-nls --enable-interpreter --with-system-zlib --enable-libgcj-multifile --enable-languages=all --enable-targets=all --with-system-unwind --without-x --with-linker-hash-style=gnu --enable-multilib --disable-multilib --with-arch=nocona export CFLAGS="-pipe -O3 -fno-fat-lto-objects -flto" export CXXFLAGS="-pipe -O3 -fno-fat-lto-objects -flto" Then I try to compile binutils (at commit 01a97082d0e9) with configure --enable-lto --enable-plugins --enable-threads --enable-gold=yes --with-zlib CFLAGS='-pipe -O3 -fno-fat-lto-objects -flto' LDFLAGS='-Wl,-O1 -Wl,-z,relro -Wl,-s' bintuils utilizies internally -Werror and compiling it fails with LTO error at: make[2]: Entering directory '/mnt/new/src/gcc/binutil-git/gas' /bin/sh ./libtool --tag=CC --mode=link gcc -W -Wall -Wstrict-prototypes -Wmissing-prototypes -Wshadow -Werror -I/home/git/binutils-gdb/gas/../zlib -pipe -O3 -fno-fat-lto-objects -flto -Wl,-O1 -Wl,-z,relro -Wl,-s -o as-new app.o as.o atof-generic.o compress-debug.o cond.o depend.o dwarf2dbg.o dw2gencfi.o ecoff.o ehopt.o expr.o flonum-copy.o flonum-konst.o flonum-mult.o frags.o hash.o input-file.o input-scrub.o listing.o literal.o macro.o messages.o output-file.o read.o remap.o sb.o stabs.o subsegs.o symbols.o write.o tc-i386.o obj-elf.o atof-ieee.o ../opcodes/libopcodes.la ../bfd/libbfd.la ../libiberty/libiberty.a -ldl libtool: link: gcc -W -Wall -Wstrict-prototypes -Wmissing-prototypes -Wshadow -Werror -I/home/git/binutils-gdb/gas/../zlib -pipe -O3 -fno-fat-lto-objects -flto -Wl,-O1 -Wl,-z -Wl,relro -Wl,-s -o as-new app.o as.o atof-generic.o compress-debug.o cond.o depend.o dwarf2dbg.o dw2gencfi.o ecoff.o ehopt.o expr.o flonum-copy.o flonum-konst.o flonum-mult.o frags.o hash.o input-file.o input-scrub.o listing.o literal.o macro.o messages.o output-file.o read.o remap.o sb.o stabs.o subsegs.o symbols.o write.o tc-i386.o obj-elf.o atof-ieee.o ../opcodes/.libs/libopcodes.a ../bfd/.libs/libbfd.a -L/src/gcc/binutil-git/zlib -lz ../libiberty/libiberty.a -ldl /home/git/binutils-gdb/bfd/compress.c: In function 'bfd_compress_section_contents': /home/git/binutils-gdb/bfd/compress.c:161:4: error: 'zlib_size' may be used uninitialized in this function [-Werror=maybe-uninitialized] memmove (buffer + compression_header_size, ^ /home/git/binutils-gdb/bfd/compress.c:88:7: note: 'zlib_size' was declared here int zlib_size; ^ lto1: all warnings being treated as errors lto-wrapper: gcc returned 1 exit status /usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../x86_64-unknown-linux-gnu/bin/ld: lto-wrapper failed collect2: error: ld returned 1 exit status Makefile:769: recipe for target 'as-new' failed make[2]: *** [as-new] Error 1 make[2]: Leaving directory '/mnt/new/src/gcc/binutil-git/gas' See also https://sourceware.org/bugzilla/show_bug.cgi?id=18313 .