re PR c++/25979 (incorrect codegen for conditional [SVO issue])

        PR c++/25979
        * tree.def: Elaborate on difference from MODIFY_EXPR.
        * doc/c-tree.texi (INIT_EXPR): Likewise.
        * gimplify.c (internal_get_tmp_var): Use INIT_EXPR.
        (gimplify_decl_expr, gimplify_init_ctor_eval): Likewise.
        (gimplify_target_expr): Likewise.
        (gimplify_cond_expr): Remove target handling.
        (gimplify_modify_expr): Don't clobber INIT_EXPR code here.
        (gimplify_expr): Clobber it here.
        (gimplify_modify_expr_rhs): Push assignment into COND_EXPR here.
        Do return slot optimization if we have an INIT_EXPR.

        PR tree-opt/24365
        * tree-inline.c (declare_return_variable): Also clear
        DECL_COMPLEX_GIMPLE_REG_P as needed in the modify_dest case.

        PR c++/16405
        * gimplify.c (gimplify_modify_expr_rhs): Re-enable *& handling.

        PR middle-end/22439
        * gimplify.c (gimplify_one_sizepos): Fix typo.

From-SVN: r110789