[Bug middle-end/27793] num_ssa_names inconsistent or immediate use iterator wrong

["rguenth at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #6 from rguenth at gcc dot gnu dot org  2006-05-29 14:04 -------
At entry of verify_ssa of afterReading() we have

(gdb) call debug_immediate_uses ()
Immediate_uses: 

verbose.3_1 : --> single use.
if (verbose.3_1 > 0) goto <L2>; else goto <L1>;

D.1752_2 : --> single use.
foo (&"%s%s"[0], D.1752_2, D.1751_3);

D.1751_3 : --> single use.
foo (&"%s%s"[0], D.1752_2, D.1751_3);

verbose_4 : --> no uses.

(gdb) print *ssa_names
$6 = {base = {num = 5, alloc = 50, vec = {0x0}}}

but walking the fn stmts we have f.i.

701           for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
(gdb) 
703               tree stmt = bsi_stmt (bsi);
(gdb) 
706               if (check_modified_stmt && stmt_modified_p (stmt))
(gdb) call debug_generic_expr (stmt)
#   VUSE <verboseD.1734_5>;
verbose.3D.1750_1 = verboseD.1734

i.e. SSA_NAME_VERSION of 5 on the VOP, which is out of range.  Indeed, in
the verification loop

          FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter,
                                    SSA_OP_ALL_USES | SSA_OP_ALL_KILLS)
            {
              op = USE_FROM_PTR (use_p);
              if (verify_use (bb, definition_block[SSA_NAME_VERSION (op)],
                              use_p, stmt, false, !is_gimple_reg (op),
                              names_defined_in_bb))
                goto err;
            }

we end up calling verify_use with

Breakpoint 7, verify_use (bb=0xb7d38e60, def_bb=0x11, use_p=0xb7db4814, 
    stmt=0xb7d37318, check_abnormal=0 '\0', is_virtual=1 '\001', 
    names_defined_in_bb=0x8a6429c)
    at /space/rguenther/src/svn/gcc-4_1-branch/gcc/tree-ssa.c:222

where def_bb is random garbage and use_p is also bogus.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27793