[Bug tree-optimization/17506] New: incorrect warning about non-existant variable

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

In patching cp/class.c I get the following error out of a bootstrap,

../../gcc/gcc/cp/class.c: In function `finish_struct_1':
../../gcc/gcc/tree.h:80: warning: 'ix' is used uninitialized in this function

*) tree.h:80 is a static inline function, which is called from finish_struct_1
*) finish_struct_1 nor that inline function have a variable called 'ix' (that I
can see).

I've attached a preprocessed source with all the #lines removed, and the
expansion of tree.h:80 split onto several lines for easy location. It has the
same problems, reporting

nathan@garibaldi:390>./cc1 -quiet -fdump-tree-all -Wall -W  -g -O2 unused.i
unused.i: In function `finish_struct_1':
unused.i:4262: warning: 'ix' is used uninitialized in this function

line 4262 is '  if (vec_ && ix_ < vec_->num)' -- a distinct lack of 'ix'.

-- 
           Summary: incorrect warning about non-existant variable
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: nathan at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17506