[Bug bootstrap/50218] New: [4.7 regression] tree-ssa-loop-ivopts.c triggers -Werror=maybe-uninitialized breaking i686-linux bootstrap

["mikpe at it dot uu.se" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50218

             Bug #: 50218
           Summary: [4.7 regression] tree-ssa-loop-ivopts.c triggers
                    -Werror=maybe-uninitialized breaking i686-linux
                    bootstrap
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: bootstrap
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: mikpe@it.uu.se


gcc-4.7-20110827 fails to bootstrap on i686-linux due to:

/mnt/scratch/gcc-4.7-20110827/gcc/tree-ssa-loop-ivopts.c: In function
'determine_use_iv_cost':
/mnt/scratch/gcc-4.7-20110827/gcc/tree-ssa-loop-ivopts.c:4846:19: error: 'comp'
may be used uninitialized in this function [-Werror=maybe-uninitialized]
/mnt/scratch/gcc-4.7-20110827/gcc/tree-ssa-loop-ivopts.c:4760:18: note: 'comp'
was declared here
cc1: all warnings being treated as errors

make[3]: *** [tree-ssa-loop-ivopts.o] Error 1
make[3]: Leaving directory `/mnt/scratch/objdir47/gcc'
make[2]: *** [all-stage2-gcc] Error 2
make[2]: Leaving directory `/mnt/scratch/objdir47'
make[1]: *** [stage2-bubble] Error 2
make[1]: Leaving directory `/mnt/scratch/objdir47'
make: *** [bootstrap] Error 2

Configured as:
/mnt/scratch/gcc-4.7-20110827/configure --prefix=/mnt/scratch/install47
--with-gmp=/home/mikpe/pkgs/linux-x86/gmp-4.3.2
--with-mpfr=/home/mikpe/pkgs/linux-x86/mpfr-2.4.2
--with-mpc=/home/mikpe/pkgs/linux-x86/mpc-0.8.2 --enable-checking=release
--enable-languages=c --disable-build-poststage1-with-cxx

I have a patch.