Some more memory usage reductions in bitmaps

[Roger Sayle]

On Tue, 1 Aug 2006, Jan Hubicka wrote:
>
> 	* tree-outof-ssa.c (check_replaceable): Do not allocate def_vars
> 	bitmap when not needed.
> 	* tree-ssa-pre.c (bitmap_set_and, bitmap_set_and_compl): Free temporary
> 	bitmaps.

This is Ok for mainline.

Thanks,

Roger
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