This patch fixes several dozen testsuite failures due to mishandling
of gimple sequences.  In the initial design we had next and prev links
inside gimple statements.  This was causing grief for two reasons:

- It is different than the existing implementation.  So the linked
list manipulation code had corner cases when inserting and removing
statements and sequences into other sequences.

- I would like to change the implementation of sequences to make them
closer to arrays.  I've found a couple of data structures that may be
useful, but for that I needed to make the gimple_seq nodes *not* be
gimple statements.  I will experiment more with this after the branch
is bootstrapping.

Moving 'next' and 'prev' out of gimple means that gimple_seq are now
exactly like STATEMENT_LIST.  I also removed the *_link_* routines, as
they were superfluous.  We don't need to distinguish
tree_stmt_iterator from block_stmt_iterator anymore.  Everything uses
gimple_stmt_iterator now.

Tested on x86.


Diego.

2008-02-19  Diego Novillo  <dnovillo@google.com>

        * tree-complex.c (expand_complex_div_wide): Call gsi_bb.
        * tree.h (std_gimplify_va_arg_expr): Change gimple_seq
        arguments to gimple_seq *.
        Update all users.
        (gimplify_parameters): Change return type to gimple_seq.
        Update all users.
        * target.h (struct gcc_target)<gimplify_va_arg_expr>:
        Change gimple_seq arguments to gimple_seq *.
        Update all users.
        * tree-phinodes.c (free_phinodes): Convert to VEC.
        Update all users.
        * omp-low.c (lower_rec_input_clauses): Change gimple_seq
        arguments to gimple_seq *.  Update all users.
        (lower_reduction_clauses): Convert sub_list to
        gimple_seq.
        (lower_regimplify): Convert PRE to gimple_seq.
        (lower_regimplify): Call gimple_seq_insert_before instead
        of tsi_link_before.
        * tree-gimple.h (get_initialized_tmp_var,
        get_formal_tmp_var, gimplify_expr, gimplify_type_sizes,
        gimplify_one_sizepos, gimplify_stmt, gimplify_and_add,
        gimplify_va_arg_expr): Change gimple_seq arguments to
        gimple_seq *.  Update all users.
        * gimple-iterator.c: Include value-prof.h.
        (gsi_link_seq_before): Remove.  Update all users.
        (gsi_link_seq_after): Remove.  Update all users.
        (gsi_link_after): Remove.  Update all users.
        (gsi_link_before): Remove.  Update all users.
        (update_bb_for_stmts): New.
        (gsi_insert_seq_nodes_before): New.
        (gsi_insert_seq_nodes_after): New.
        (gsi_insert_seq_before): Re-write.  Call
        gsi_insert_seq_nodes_before.
        (gsi_insert_seq_after): Re-write.  Call
        gsi_insert_seq_nodes_after.
        (gsi_replace): Re-enable EH updating.
        (update_modified_stmt): Move earlier in the file.
        (gsi_insert_after): Re-write.  Call
        gsi_insert_seq_nodes_after.
        (gsi_insert_before): Re-write.  Call
        gsi_insert_seq_nodes_before.
        (gsi_remove): Move from gimple.h.  Re-write.
        * langhooks.h (struct lang_hooks): Change gimple_seq
        arguments for gimplify_expr to gimple_seq *.
        Update all users.
        * coretypes.h (struct gimple_seq_d): Rename from struct
        gimple_sequence.  Update all users.
        (struct gimple_seq_node_d): New.
        (gimple_seq_node): New.
        (const_gimple_seq_node): New.
        * tree-flow.h (force_gimple_operand): Change gimple_seq
        argument to gimple_seq *.  Update all users.
        * c-common.h (c_gimplify_expr): Change gimple_seq
        argument to gimple_seq *.  Update all users.
        * Makefile.in (build):
        * gimple.c (gimple_seq_cache): New.
        (gimple_seq_alloc): Take sequences from gimple_seq_cache,
        if possible.
        (gimple_seq_free): New.
        (gimple_seq_add_stmt): Rename from gimple_seq_add.
        Change gimple_seq argument to gimple_seq *.  Update all users.
        (gimple_seq_add_seq): Rename from gimple_seq_append.
        Update all users.
        (gimple_remove): Remove.  Update all users.
        (gimple_seq_reverse): Remove unused function.
        (gimple_set_bb): Only update block-to-labels map if
        CFUN->CFG exists.
        * gimple.h (struct gimple_seq_node_d): New.
        (struct gimple_seq_d): Change fields 'first' and 'last'
        to type gimple_seq_node.  Update all users.
        Add field 'next_free'.
        (gimple_seq_first): Change return type to
        gimple_seq_node.  Update all users.
        (gimple_seq_first_stmt): New.
        (gimple_seq_last): Change return type to gimple_seq_node.
        Update all users.
        (gimple_seq_last_stmt): New.
        (gimple_seq_set_first): Change second argument to type
        gimple_seq_node.  Update all users.
        (gimple_seq_set_last): Change second argument to type
        gimple_seq_node.  Update all users.
        (struct gimple_statement_base): Remove field 'next' and
        'prev'.  Update all users.
        (struct gimple_statement_omp): Change fields of type
        struct gimple_sequence to type gimple_seq.  Update all
        users.
        (struct gimple_statement_bind): Likewise.
        (struct gimple_statement_catch): Likewise.
        (struct gimple_statement_eh_filter): Likewise.
        (struct gimple_statement_try): Likewise.
        (struct gimple_statement_wce): Likewise.
        (struct gimple_statement_omp_for): Likewise.
        (gimple_set_prev): Remove.  Update all users.
        (gimple_set_next): Remove.  Update all users.
        (gimple_next): Remove.  Update all users.
        (gimple_prev): Remove.  Update all users.
        (gimple_seq_bb): New.
        (gimple_catch_handler_ptr): New.
        (gimple_stmt_iterator): Remove field 'stmt'.
        Add field 'ptr'.  Update all users.
        (gsi_remove): Move to gimple-iterator.c
        * tree-cfg.c (pass_build_cfg): Re-enable PROP_gimple_leh.
        * Makefile.in (builtins.o-warn, expr.o-warn, dse.o-warn,
        ebitmap.o-warn, lower-subreg.o-warn, tree-chrec.o-warn):
        Change -Wno-error to -Wno-uninitialized.