Add value range support into memcpy/memset expansion

[Jan Hubicka]

> Hi,
> this patch makes it possible to access value range info from setmem/movstr that
> I plan to use in i386 memcpy/memset expansion code.  It is all quite
> straighforward except that I need to deal with cases where max size does not
> fit in HOST_WIDE_INT where I use maximal value as a marker.  It is then
> translated as NULL pointer to the expander that is bit inconsistent with other
> places that use -1 as marker of unknown value.
> 
> I also think we lose some cases because of TER replacing out the SSA_NAME by
> something else, but it seems to work in quite many cases. This can be probably
> tracked incrementally by disabling TER here or finally getting away from
> expanding calls via the generic route.
> 
> Bootstrapped/regtested x86_64-linux, OK?
> 
> Honza
> 
> 	* doc/md.texi (setmem, movstr): Update documentation.
> 	* builtins.c (determine_block_size): New function.
> 	(expand_builtin_memcpy): Use it and pass it to
> 	emit_block_move_hints.
> 	(expand_builtin_memset_args): Use it and pass it to
> 	set_storage_via_setmem.
> 	* expr.c (emit_block_move_via_movmem): Add min_size/max_size parameters;
> 	update call to expander.
> 	(emit_block_move_hints): Add min_size/max_size parameters.
> 	(clear_storage_hints): Likewise.
> 	(set_storage_via_setmem): Likewise.
> 	(clear_storage): Update.
> 	* expr.h (emit_block_move_hints, clear_storage_hints,
> 	set_storage_via_setmem): Update prototype.

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http://gcc.gnu.org/ml/gcc-patches/2013-09/msg02011.html

Honza