[Bug debug/44971] New: -fcompare-debug failure with uninitialized read in walk_gimple_stmt

["zsojka at seznam dot cz" <gcc-bugzilla at gcc dot gnu dot org>]

Command line:
$ gcc -O2 -fcompare-debug testcase.c

Valgrind output:
$ valgrind -q --trace-children=yes
/mnt/svn/gcc-trunk/binary-162222-lto-fortran-checking-yes-rtl-df/bin/gcc -O2
-fcompare-debug testcase.c
testcase.c: In function '_XftCloseint':
testcase.c:21:3: warning: passing argument 1 of '_XftintInfoGet' makes pointer
from integer without a cast [enabled by default]
testcase.c:12:6: note: expected 'int *' but argument is of type 'int'
testcase.c:22:13: warning: assignment from incompatible pointer type [enabled
by default]
testcase.c:22:48: warning: assignment from incompatible pointer type [enabled
by default]
==3128== Conditional jump or move depends on uninitialised value(s)
==3128==    at 0x70BFBB: walk_gimple_stmt (gimple.c:1627)
==3128==    by 0x955003: dump_enumerated_decls (tree-ssa-live.c:1264)
==3128==    by 0x8F7B98: execute_cleanup_cfg_post_optimizing
(tree-optimize.c:212)
==3128==    by 0x7B777D: execute_one_pass (passes.c:1563)
==3128==    by 0x7B7A14: execute_pass_list (passes.c:1618)
==3128==    by 0x8F8525: tree_rest_of_compilation (tree-optimize.c:450)
==3128==    by 0xAADBF5: cgraph_expand_function (cgraphunit.c:1629)
==3128==    by 0xAB0A29: cgraph_optimize (cgraphunit.c:1708)
==3128==    by 0xAB101A: cgraph_finalize_compilation_unit (cgraphunit.c:1171)
==3128==    by 0x4DE632: c_write_global_declarations (c-decl.c:9698)
==3128==    by 0x8A41E5: toplev_main (toplev.c:990)
==3128==    by 0x6589BBC: (below main) (in /lib64/libc-2.11.2.so)
==3128== 
gcc: error: testcase.c: -fcompare-debug failure (length)

Tested revisions:
r162222 - fail
r162056 - fail
r161659 - ICEs
r161170 - OK


-- 
           Summary: -fcompare-debug failure with uninitialized read in
                    walk_gimple_stmt
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: zsojka at seznam dot cz
  GCC host triplet: x86_64-pc-linux-gnu
GCC target triplet: x86_64-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44971