http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56273
Bug #: 56273 Summary: [4.8 regression] Bogus -Warray-bounds warning Classification: Unclassified Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: other AssignedTo: unassig...@gcc.gnu.org ReportedBy: dan...@constexpr.org The following C++ code cause current gcc master to emit an incorrect array bounds warning: $ cat test.cpp struct type { bool a, b; bool get_b() { return b; } }; type stuff[9u]; void bar(); void foo() { for(unsigned i = 0u; i < 9u; i++) { if(!stuff[i].a) { continue; } bar(); for(unsigned j = i + 1u; j < 9u; j++) { if(stuff[j].a && stuff[j].get_b()) { return; } } } } $ g++-4.8.0-pre9999 -Warray-bounds -O3 -c test.cpp test.cpp: In function ‘void foo()’: test.cpp:22:17: warning: array subscript is above array bounds [-Warray-bounds] if(stuff[j].a && stuff[j].get_b()) { ^ I appreciate static analyzers as much as everyone, but having false positives in the normal warnings (especially ones enabled at -Wall) can be annoying. GCC was build from git master just now: $ g++-4.8.0-pre9999 -v Using built-in specs. COLLECT_GCC=g++-4.8.0-pre9999 COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/4.8.0-pre9999/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: /var/tmp/portage/sys-devel/gcc-4.8.0_pre9999/work/gcc-4.8.0-9999/configure --prefix=/usr --bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/4.8.0-pre9999 --includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.0-pre9999/include --datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.0-pre9999 --mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.0-pre9999/man --infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.0-pre9999/info --with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.0-pre9999/include/g++-v4 --host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --disable-altivec --disable-fixed-point --with-ppl --with-cloog --disable-ppl-version-check --with-cloog-include=/usr/include/cloog-ppl --enable-lto --enable-nls --without-included-gettext --with-system-zlib --enable-obsolete --disable-werror --enable-secureplt --enable-multilib --with-multilib-list=m32,m64 --enable-libmudflap --disable-libssp --enable-libgomp --with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/4.8.0-pre9999/python --enable-checking=release --disable-libgcj --enable-libstdcxx-time --enable-languages=c,c++,fortran --enable-shared --enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu --enable-targets=all --with-bugurl=http://bugs.gentoo.org/ --with-pkgversion='Gentoo 4.8.0_pre9999' Thread model: posix gcc version 4.8.0-pre9999 20130210 (experimental) commit bc85f3af1b43674782c9b5bb2240117f293b5530 (Gentoo 4.8.0_pre9999)