[Bug middle-end/51544] New: uninitialized variable false positive prevents bootstrap at -O3

[matt at use dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51544

             Bug #: 51544
           Summary: uninitialized variable false positive prevents
                    bootstrap at -O3
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: m...@use.net


I checked by hand, and this looks like a false positive to me. It doesn't come
up without
-O[3,fast].

NOTE: I have hand-modified my build/bootstrap-lto.mk to use -Ofast. It's
possible that using the bootstrap-O3 build-config will reproduce it as well.

$ ~/src/gcc-trunk/configure --enable-bootstrap --prefix=/home/matt
--enable-clocale=gnu --with-system-zlib --with-demangler-in-ld --enable-lto
--with-fpmath=sse --enable-languages=c,c++,lto
--with-build-config=bootstrap-lto --enable-build-with-cxx --disable-libmudflap
--with-cpu=core2 --with-tune=core2 --disable-libssp

$ make -j7 profiledbootstrap

/home/matt/src/gcc-trunk/gcc/cp/parser.c: In function ‘bool
cp_parser_ctor_initializer_opt_and_function_body(cp_parser*)’:
/home/matt/src/gcc-trunk/gcc/cp/parser.c:17533:43: error: ‘list’ may be used
uninitialized in this function [-Werror=maybe-uninitialized]