4.5 backport request...

[DJ Delorie]

May I backport this change to 4.5 ?  rx-elf can use this for a
performance boost (a separate 4.5 target patch would be needed for
that)

2010-10-19  DJ Delorie  <dj@redhat.com>

	* doc/tm.texi.in (TARGET_ASM_JUMP_ALIGN_MAX_SKIP): New.
	(TARGET_ASM_LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP): Change to hook.
	(TARGET_ASM_LOOP_ALIGN_MAX_SKIP): Likewise.
	(TARGET_ASM_LABEL_ALIGN_MAX_SKIP): Likewise.
	* doc/tm.texi: Regenerate.
	* targhooks.h (default_label_align_after_barrier_max_skip,
	default_loop_align_max_skip, default_label_align_max_skip,
	default_jump_align_max_skip): Declare.
	* target.def (label_align_after_barrier_max_skip): New.
	(loop_align_max_skip): New.
	(label_align_max_skip): New.
	(jump_align_max_skip): New.
	* system.h (poison): Add those macros to the list.
	* final.c (LABEL_ALIGN_MAX_SKIP): Remove.
	(LOOP_ALIGN_MAX_SKIP): Remove.
	(LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP): Remove.
	(JUMP_ALIGN_MAX_SKIP): Remove.
	(default_label_align_after_barrier_max_skip): New.
	(default_loop_align_max_skip): New.
	(default_label_align_max_skip): New.
	(default_jump_align_max_skip): New.
	(compute_alignments): Use the new hooks.
	(shorten_branches): Likewise.