[patch] for PR32018

[Richard Guenther]

On 5/22/07, Zdenek Dvorak <rakdver@kam.mff.cuni.cz> wrote:
> Hello,
>
> the copy field of loop structure (that contains reference to the copy of
> the loop during loop duplication) is not cleared, and may point to a
> loop that is later removed and freed.  This cases ICE during garbage
> collection.
>
> Clearing the field when it is not used would solve the problem, but
> actually a more appropriate fix seems to be using the same mechanism for
> storing loop copies as we do for basic blocks (storing the information
> in temporary hash tables).
>
> Bootstrapped & regtested on i686.

This is ok.

Thanks,
Richard.

> Zdenek
>
>         PR middle-end/32018
>         * tree-ssa-threadupdate.c (thread_through_loop_header): Use
>         set_loop_copy.
>         (thread_through_all_blocks): Call initialize_original_copy_tables
>         and free_original_copy_tables.
>         * cfgloopmanip.c (duplicate_loop, duplicate_loop_to_header_edge):
>         Use set_loop_copy.
>         * tree-cfg.c (tree_duplicate_sese_region): Ditto.
>         * cfghooks.c (duplicate_block): Use get_loop_copy.
>         * cfg.c: Include cfgloop.h.
>         (loop_copy): New hash table.
>         (initialize_original_copy_tables): Initialize loop_copy table.
>         (free_original_copy_tables): Free loop_copy table.
>         (copy_original_table_clear, copy_original_table_set,
>         set_loop_copy, get_loop_copy): New functions.
>         (set_bb_original, set_bb_copy): Use copy_original_table_set.
>         * cfgloop.h (struct loop): Remove copy field.
>         * Makefile.in (cfg.o): Add CFGLOOP_H dependency.
>         * basic-block.h (set_loop_copy, get_loop_copy): Declare.
>